Updates to the 'vtshim' extension.

FossilOrigin-Name: 163c6cdf93451cb4ae7655266654d4aec2b94c4ceb0a6fc68859ecc73bf393a9
Add experimental 'xShadowName2' method for virtual table modules.
2022-07-22 20:48:04 +00:00 · 2022-07-22 20:24:38 +00:00 · 2022-07-22 19:28:04 +00:00 · 2022-07-22 18:25:04 +00:00 · 2022-07-22 14:52:29 +00:00 · 2022-07-21 18:37:50 +00:00
401 changed files with 76166 additions and 7991 deletions
@@ -180,7 +180,7 @@ LIBOBJS0 = alter.lo analyze.lo attach.lo auth.lo \
         fts3_unicode.lo fts3_unicode2.lo fts3_write.lo \
 	 fts5.lo \
         func.lo global.lo hash.lo \
-         icu.lo insert.lo json1.lo legacy.lo loadext.lo \
+         icu.lo insert.lo json.lo legacy.lo loadext.lo \
         main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
         memdb.lo memjournal.lo \
         mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
@@ -234,6 +234,7 @@ SRC = \
  $(TOP)/src/hash.h \
  $(TOP)/src/hwtime.h \
  $(TOP)/src/insert.c \
+  $(TOP)/src/json.c \
  $(TOP)/src/legacy.c \
  $(TOP)/src/loadext.c \
  $(TOP)/src/main.c \
@@ -366,7 +367,6 @@ SRC += \
  $(TOP)/ext/rbu/sqlite3rbu.h \
  $(TOP)/ext/rbu/sqlite3rbu.c
 SRC += \
-  $(TOP)/ext/misc/json1.c \
  $(TOP)/ext/misc/stmt.c

 # Generated source code files
@@ -460,6 +460,7 @@ TESTSRC += \
  $(TOP)/ext/misc/normalize.c \
  $(TOP)/ext/misc/percentile.c \
  $(TOP)/ext/misc/prefixes.c \
+  $(TOP)/ext/misc/qpvtab.c \
  $(TOP)/ext/misc/regexp.c \
  $(TOP)/ext/misc/remember.c \
  $(TOP)/ext/misc/series.c \
@@ -502,6 +503,7 @@ TESTSRC2 = \
  $(TOP)/src/pcache1.c \
  $(TOP)/src/select.c \
  $(TOP)/src/tokenize.c \
+  $(TOP)/src/treeview.c \
  $(TOP)/src/utf.c \
  $(TOP)/src/util.c \
  $(TOP)/src/vdbeapi.c \
@@ -608,7 +610,7 @@ TESTOPTS = --verbose=file --output=test-out.txt

 # Extra compiler options for various shell tools
 #
-SHELL_OPT = -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_FTS4
+SHELL_OPT = -DSQLITE_ENABLE_FTS4
 #SHELL_OPT += -DSQLITE_ENABLE_FTS5
 SHELL_OPT += -DSQLITE_ENABLE_RTREE
 SHELL_OPT += -DSQLITE_ENABLE_EXPLAIN_COMMENTS
@@ -618,18 +620,18 @@ SHELL_OPT += -DSQLITE_ENABLE_DBPAGE_VTAB
 SHELL_OPT += -DSQLITE_ENABLE_DBSTAT_VTAB
 SHELL_OPT += -DSQLITE_ENABLE_BYTECODE_VTAB
 SHELL_OPT += -DSQLITE_ENABLE_OFFSET_SQL_FUNC
-FUZZERSHELL_OPT = -DSQLITE_ENABLE_JSON1
-FUZZCHECK_OPT = -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_MEMSYS5 -DSQLITE_OSS_FUZZ
+FUZZERSHELL_OPT = 
+FUZZCHECK_OPT = -DSQLITE_ENABLE_MEMSYS5 -DSQLITE_OSS_FUZZ
 FUZZCHECK_OPT += -DSQLITE_MAX_MEMORY=50000000
 FUZZCHECK_OPT += -DSQLITE_PRINTF_PRECISION_LIMIT=1000
 FUZZCHECK_OPT += -DSQLITE_ENABLE_FTS4
 FUZZCHECK_OPT += -DSQLITE_ENABLE_FTS3_PARENTHESIS
-#FUZZCHECK_OPT += -DSQLITE_ENABLE_FTS5
+FUZZCHECK_OPT += -DSQLITE_ENABLE_FTS5
 FUZZCHECK_OPT += -DSQLITE_ENABLE_RTREE
 FUZZCHECK_OPT += -DSQLITE_ENABLE_GEOPOLY
 FUZZCHECK_OPT += -DSQLITE_ENABLE_DBSTAT_VTAB
 FUZZCHECK_OPT += -DSQLITE_ENABLE_BYTECODE_VTAB
-FUZZCHECK_SRC = $(TOP)/test/fuzzcheck.c $(TOP)/test/ossfuzz.c
+FUZZCHECK_SRC = $(TOP)/test/fuzzcheck.c $(TOP)/test/ossfuzz.c $(TOP)/test/fuzzinvariants.c
 DBFUZZ_OPT =

 # This is the default Makefile target.  The objects listed here
@@ -873,6 +875,9 @@ hash.lo:	$(TOP)/src/hash.c $(HDR)
 insert.lo:	$(TOP)/src/insert.c $(HDR)
 	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/insert.c

+json.lo:	$(TOP)/src/json.c $(HDR)
+	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/json.c
+
 legacy.lo:	$(TOP)/src/legacy.c $(HDR)
 	$(LTCOMPILE) $(TEMP_STORE) -c $(TOP)/src/legacy.c

@@ -1176,9 +1181,6 @@ userauth.lo:	$(TOP)/ext/userauth/userauth.c $(HDR) $(EXTHDR)
 sqlite3session.lo:	$(TOP)/ext/session/sqlite3session.c $(HDR) $(EXTHDR)
 	$(LTCOMPILE) -DSQLITE_CORE -c $(TOP)/ext/session/sqlite3session.c

-json1.lo:	$(TOP)/ext/misc/json1.c
-	$(LTCOMPILE) -DSQLITE_CORE -c $(TOP)/ext/misc/json1.c
-
 stmt.lo:	$(TOP)/ext/misc/stmt.c
 	$(LTCOMPILE) -DSQLITE_CORE -c $(TOP)/ext/misc/stmt.c

@@ -1251,7 +1253,10 @@ coretestprogs:	$(TESTPROGS)
 testprogs:	coretestprogs srcck1$(BEXE) fuzzcheck$(TEXE) sessionfuzz$(TEXE)

 # A very detailed test running most or all test cases
-fulltest:	$(TESTPROGS) fuzztest
+fulltest:	alltest fuzztest
+
+# Run most or all tcl test cases
+alltest:	$(TESTPROGS)
 	./testfixture$(TEXE) $(TOP)/test/all.test $(TESTOPTS)

 # Really really long testing
@@ -1276,6 +1281,12 @@ valgrindfuzz:	fuzzcheck$(TEXT) $(FUZZDATA) sessionfuzz$(TEXE) $(TOP)/test/sessio
 tcltest:	./testfixture$(TEXE)
 	./testfixture$(TEXE) $(TOP)/test/veryquick.test $(TESTOPTS)

+# Runs all the same tests cases as the "tcltest" target but uses
+# the testrunner.tcl script to run them in multiple cores
+# concurrently.
+testrunner:	testfixture$(TEXE)
+	./testfixture$(TEXE) $(TOP)/test/testrunner.tcl
+
 # Minimal testing that runs in less than 3 minutes
 #
 quicktest:	./testfixture$(TEXE)
@@ -1508,3 +1519,135 @@ sqlite3.def: $(REAL_LIBOBJ)
 sqlite3.dll: $(REAL_LIBOBJ) sqlite3.def
 	$(TCC) -shared -o $@ sqlite3.def \
 		-Wl,"--strip-all" $(REAL_LIBOBJ)
+
+
+#
+# fiddle/wasm section
+#
+fiddle_dir = ext/fiddle
+fiddle_dir_abs = $(TOP)/$(fiddle_dir)
+# ^^^ some emcc opts require absolute paths
+fiddle_html = $(fiddle_dir)/fiddle.html
+fiddle_module_js = $(fiddle_dir)/fiddle-module.js
+sqlite3_wasm_js = $(fiddle_dir)/sqlite3.js
+sqlite3_wasm = $(fiddle_dir)/sqlite3.wasm
+#emcc_opt = -O0
+#emcc_opt = -O1
+#emcc_opt = -O2
+#emcc_opt = -O3
+emcc_opt = -Oz
+emcc_flags = $(emcc_opt) -sALLOW_TABLE_GROWTH -sSTRICT_JS \
+        -sENVIRONMENT=web -sMODULARIZE \
+        -sEXPORTED_RUNTIME_METHODS=@$(fiddle_dir_abs)/EXPORTED_RUNTIME_METHODS \
+        -sDYNAMIC_EXECUTION=0 \
+        -I. $(SHELL_OPT)
+$(fiddle_module_js): Makefile sqlite3.c shell.c \
+    $(fiddle_dir)/EXPORTED_RUNTIME_METHODS \
+    $(fiddle_dir)/EXPORTED_FUNCTIONS.fiddle
+	emcc -o $@ $(emcc_flags) \
+        -sEXPORT_NAME=initFiddleModule \
+        -sEXPORTED_FUNCTIONS=@$(fiddle_dir_abs)/EXPORTED_FUNCTIONS.fiddle \
+        -DSQLITE_SHELL_FIDDLE \
+        sqlite3.c shell.c
+	gzip < $@ > $@.gz
+	gzip < $(fiddle_dir)/fiddle-module.wasm > $(fiddle_dir)/fiddle-module.wasm.gz
+$(sqlite3_wasm_js): Makefile sqlite3.c \
+    $(fiddle_dir)/sqlite3-api.js \
+    $(fiddle_dir)/EXPORTED_RUNTIME_METHODS \
+    $(fiddle_dir)/EXPORTED_FUNCTIONS.sqlite3-api
+	emcc -o $@ $(emcc_flags) \
+        -sEXPORT_NAME=initSqlite3Module \
+        -sEXPORTED_FUNCTIONS=@$(fiddle_dir_abs)/EXPORTED_FUNCTIONS.sqlite3-api \
+        --post-js=$(fiddle_dir)/sqlite3-api.js \
+        --no-entry \
+        sqlite3.c
+	gzip < $@ > $@.gz
+	gzip < $(sqlite3_wasm) > $(sqlite3_wasm).gz
+	gzip < $(fiddle_dir)/sqlite3-api.js > $(fiddle_dir)/sqlite3-api.js.gz
+$(fiddle_dir)/fiddle.js.gz: $(fiddle_dir)/fiddle.js
+	gzip < $< > $@
+$(fiddle_dir)/sqlite3-api.js.gz: $(fiddle_dir)/sqlite3-api.js
+	gzip < $< > $@
+
+fiddle_generated = $(fiddle_module_js) $(fiddle_module_js).gz \
+                   $(fiddle_dir)/fiddle-module.wasm \
+                   $(fiddle_dir)/fiddle-module.wasm.gz \
+                   $(fiddle_dir)/fiddle.js.gz
+sqlite3_wasm_generated = \
+                   $(sqlite3_wasm) $(sqlite3_wasm).gz \
+                   $(sqlite3_wasm_js) $(sqlite3_wasm_js).gz \
+                   $(fiddle_dir)/sqlite3.js.gz \
+                   $(fiddle_dir)/sqlite3-api.js.gz
+
+clean-wasm:
+	rm -f $(fiddle_generated) $(sqlite3_wasm_generated)
+clean: clean-wasm
+fiddle: $(fiddle_module_js) $(fiddle_dir)/fiddle.js.gz
+sqlite3-wasm: $(sqlite3_wasm_js)
+wasm: fiddle sqlite3-wasm
+########################################################################
+# Explanation of the emcc build flags follows. Full docs for these can
+# be found at:
+#
+#  https://github.com/emscripten-core/emscripten/blob/main/src/settings.js
+#
+# -sENVIRONMENT=web: elides bootstrap code related to non-web JS
+#  environments like node.js. Removing this makes the output a tiny
+#  tick larger but hypothetically makes it more portable to
+#  non-browser JS environments.
+#
+# -sMODULARIZE: changes how the generated code is structured to avoid
+#  declaring a global Module object and instead installing a function
+#  which loads and initialized the module. The function is named...
+#
+# -sEXPORT_NAME=jsFunctionName (see -sMODULARIZE)
+#
+# -sEXPORTED_RUNTIME_METHODS=@/absolute/path/to/file: a file
+#  containing a list of emscripten-supplied APIs, one per line, which
+#  must be exported into the generated JS. Must be an absolute path!
+#
+# -sEXPORTED_FUNCTIONS=@/absolute/path/to/file: a file containing a
+#  list of C functions, one per line, which must be exported via wasm
+#  so they're visible to JS. C symbols names in that file must all
+#  start with an underscore for reasons known only to the emcc
+#  developers. e.g., _sqlite3_open_v2 and _sqlite3_finalize. Must be
+#  an absolute path!
+#
+# -sSTRICT_JS ensures that the emitted JS code includes the 'use
+#  strict' option. Note that -sSTRICT is more broadly-scoped and
+#  results in build errors.
+#
+# -sALLOW_TABLE_GROWTH is required for (at a minimum) the UDF-binding
+#  feature.
+#
+# -sDYNAMIC_EXECUTION=0 disables eval() and the Function constructor.
+#  If the build runs without these, it's preferable to use this flag
+#  because certain execution environments disallow those constructs.
+#  This flag is not strictly necessary, however.
+#
+# -sWASM_BIGINT is UNTESTED but "should" allow the int64-using C APIs
+#  to work with JS/wasm, insofar as the JS environment supports the
+#  BigInt type. That support requires an extremely recent browser:
+#  Safari didn't get that support until late 2020.
+#
+# --no-entry: for compiling library code with no main(). If this is
+#  not supplied and the code has a main(), it is called as part of the
+#  module init process. Note that main() is #if'd out of shell.c
+#  (renamed) when building in wasm mode.
+#
+# --pre-js/--post-js=FILE relative or absolute paths to JS files to
+#  prepend/append to the emcc-generated bootstrapping JS. It's
+#  easier/faster to develop with separate JS files (reduces rebuilding
+#  requirements) but certain configurations, namely -sMODULARIZE, may
+#  require using at least a --pre-js file. They can be used
+#  individually and need not be paired.
+#
+# -O0..-O3 and -Oz: optimization levels affect not only C-style
+#  optimization but whether or not the resulting generated JS code
+#  gets minified. -O0 compiles _much_ more quickly than -O3 or -Oz,
+#  and doesn't minimize any JS code, so is recommended for
+#  development. -O3 or -Oz are recommended for deployment, but
+#  primarily because -Oz will shrink the wasm file notably. JS-side
+#  minification makes little difference in terms of overall
+#  distributable size.
+########################################################################
@@ -363,7 +363,6 @@ SQLITE_TCL_DEP =
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_FTS3=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_RTREE=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_GEOPOLY=1
-OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_JSON1=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_STMTVTAB=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_DBPAGE_VTAB=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_DBSTAT_VTAB=1
@@ -580,17 +579,17 @@ RCC = $(RC) -DSQLITE_OS_WIN=1 -I. -I$(TOP) -I$(TOP)\src $(RCOPTS) $(RCCOPTS)
 #
 !IF $(USE_STDCALL)!=0 || $(FOR_WIN10)!=0
 !IF "$(PLATFORM)"=="x86"
-CORE_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
-SHELL_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+CORE_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+SHELL_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
 # <<mark>>
-TEST_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall -DINCLUDE_SQLITE_TCL_H=1 -DSQLITE_TCLAPI=__cdecl
+TEST_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall -DINCLUDE_SQLITE_TCL_H=1 -DSQLITE_TCLAPI=__cdecl
 # <</mark>>
 !ELSE
 !IFNDEF PLATFORM
-CORE_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
-SHELL_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+CORE_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+SHELL_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
 # <<mark>>
-TEST_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall -DINCLUDE_SQLITE_TCL_H=1 -DSQLITE_TCLAPI=__cdecl
+TEST_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall -DINCLUDE_SQLITE_TCL_H=1 -DSQLITE_TCLAPI=__cdecl
 # <</mark>>
 !ELSE
 CORE_CCONV_OPTS =
@@ -1248,7 +1247,7 @@ LIBOBJS0 = vdbe.lo parse.lo alter.lo analyze.lo attach.lo auth.lo \
         fts3_tokenize_vtab.lo fts3_unicode.lo fts3_unicode2.lo fts3_write.lo \
         fts5.lo \
         func.lo global.lo hash.lo \
-         icu.lo insert.lo json1.lo legacy.lo loadext.lo \
+         icu.lo insert.lo json.lo legacy.lo loadext.lo \
         main.lo malloc.lo mem0.lo mem1.lo mem2.lo mem3.lo mem5.lo \
         memdb.lo memjournal.lo \
         mutex.lo mutex_noop.lo mutex_unix.lo mutex_w32.lo \
@@ -1315,6 +1314,7 @@ SRC00 = \
  $(TOP)\src\global.c \
  $(TOP)\src\hash.c \
  $(TOP)\src\insert.c \
+  $(TOP)\src\json.c \
  $(TOP)\src\legacy.c \
  $(TOP)\src\loadext.c \
  $(TOP)\src\main.c \
@@ -1445,7 +1445,6 @@ SRC07 = \
  $(TOP)\ext\rtree\rtree.c \
  $(TOP)\ext\session\sqlite3session.c \
  $(TOP)\ext\rbu\sqlite3rbu.c \
-  $(TOP)\ext\misc\json1.c \
  $(TOP)\ext\misc\stmt.c

 # Extension header files, part 1.
@@ -1579,6 +1578,7 @@ TESTEXT = \
  $(TOP)\ext\misc\normalize.c \
  $(TOP)\ext\misc\percentile.c \
  $(TOP)\ext\misc\prefixes.c \
+  $(TOP)\ext\misc\qpvtab.c \
  $(TOP)\ext\misc\regexp.c \
  $(TOP)\ext\misc\remember.c \
  $(TOP)\ext\misc\series.c \
@@ -1695,16 +1695,17 @@ SHELL_COMPILE_OPTS = $(SHELL_COMPILE_OPTS) -DSQLITE_ENABLE_OFFSET_SQL_FUNC=1
 # <<mark>>
 # Extra compiler options for various test tools.
 #
-MPTESTER_COMPILE_OPTS = -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_FTS5
-FUZZERSHELL_COMPILE_OPTS = -DSQLITE_ENABLE_JSON1
-FUZZCHECK_OPTS = -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_MEMSYS5 -DSQLITE_OSS_FUZZ -DSQLITE_MAX_MEMORY=50000000 -DSQLITE_PRINTF_PRECISION_LIMIT=1000
+MPTESTER_COMPILE_OPTS = -DSQLITE_ENABLE_FTS5
+FUZZERSHELL_COMPILE_OPTS =
+FUZZCHECK_OPTS = -DSQLITE_ENABLE_MEMSYS5 -DSQLITE_OSS_FUZZ -DSQLITE_MAX_MEMORY=50000000 -DSQLITE_PRINTF_PRECISION_LIMIT=1000
 FUZZCHECK_OPTS = $(FUZZCHECK_OPTS) -DSQLITE_ENABLE_FTS4
+FUZZCHECK_OPTS = $(FUZZCHECK_OPTS) -DSQLITE_ENABLE_FTS5
 FUZZCHECK_OPTS = $(FUZZCHECK_OPTS) -DSQLITE_ENABLE_RTREE
 FUZZCHECK_OPTS = $(FUZZCHECK_OPTS) -DSQLITE_ENABLE_GEOPOLY
 FUZZCHECK_OPTS = $(FUZZCHECK_OPTS) -DSQLITE_ENABLE_DBSTAT_VTAB
 FUZZCHECK_OPTS = $(FUZZCHECK_OPTS) -DSQLITE_ENABLE_BYTECODE_VTAB

-FUZZCHECK_SRC = $(TOP)\test\fuzzcheck.c $(TOP)\test\ossfuzz.c
+FUZZCHECK_SRC = $(TOP)\test\fuzzcheck.c $(TOP)\test\ossfuzz.c $(TOP)\test\fuzzinvariants.c
 OSSSHELL_SRC = $(TOP)\test\ossshell.c $(TOP)\test\ossfuzz.c
 DBFUZZ_COMPILE_OPTS = -DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION
 KV_COMPILE_OPTS = -DSQLITE_THREADSAFE=0 -DSQLITE_DIRECT_OVERFLOW_READ
@@ -1989,6 +1990,9 @@ hash.lo:	$(TOP)\src\hash.c $(HDR)
 insert.lo:	$(TOP)\src\insert.c $(HDR)
 	$(LTCOMPILE) $(CORE_COMPILE_OPTS) -c $(TOP)\src\insert.c

+json.lo:	$(TOP)\src\json.c $(HDR)
+	$(LTCOMPILE) $(CORE_COMPILE_OPTS) -c $(TOP)\src\json.c
+
 legacy.lo:	$(TOP)\src\legacy.c $(HDR)
 	$(LTCOMPILE) $(CORE_COMPILE_OPTS) -c $(TOP)\src\legacy.c

@@ -2297,9 +2301,6 @@ fts3_unicode2.lo:	$(TOP)\ext\fts3\fts3_unicode2.c $(HDR) $(EXTHDR)
 fts3_write.lo:	$(TOP)\ext\fts3\fts3_write.c $(HDR) $(EXTHDR)
 	$(LTCOMPILE) $(CORE_COMPILE_OPTS) $(NO_WARN) -DSQLITE_CORE -c $(TOP)\ext\fts3\fts3_write.c

-json1.lo:	$(TOP)\ext\misc\json1.c $(HDR) $(EXTHDR)
-	$(LTCOMPILE) $(CORE_COMPILE_OPTS) $(NO_WARN) -DSQLITE_CORE -c $(TOP)\ext\misc\json1.c
-
 stmt.lo:	$(TOP)\ext\misc\stmt.c $(HDR) $(EXTHDR)
 	$(LTCOMPILE) $(CORE_COMPILE_OPTS) $(NO_WARN) -DSQLITE_CORE -c $(TOP)\ext\misc\stmt.c

@@ -2391,7 +2392,6 @@ TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) -DSQLITE_DEFAULT_PAGE_SIZE=1024
 TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) -DSQLITE_ENABLE_STMTVTAB=1
 TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) -DSQLITE_ENABLE_DBPAGE_VTAB=1
 TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) -DSQLITE_ENABLE_BYTECODE_VTAB=1
-TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) -DSQLITE_ENABLE_JSON1=1
 TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) -DSQLITE_CKSUMVFS_STATIC=1
 TESTFIXTURE_FLAGS = $(TESTFIXTURE_FLAGS) $(TEST_CCONV_OPTS)

@@ -2437,7 +2437,9 @@ coretestprogs:	$(TESTPROGS)

 testprogs:	coretestprogs srcck1.exe fuzzcheck.exe sessionfuzz.exe

-fulltest:	$(TESTPROGS) fuzztest
+fulltest:	alltest fuzztest
+
+alltest:	$(TESTPROGS)
 	@set PATH=$(LIBTCLPATH);$(PATH)
 	.\testfixture.exe $(TOP)\test\all.test $(TESTOPTS)

@@ -2465,10 +2467,20 @@ quicktest:	testfixture.exe sourcetest
 # This is the common case.  Run many tests that do not take too long,
 # including fuzzcheck, sqlite3_analyzer, and sqldiff tests.
 #
-test:	$(TESTPROGS) sourcetest fuzztest
+test:	$(TESTPROGS) sourcetest fuzztest tcltest
+
+# The veryquick.test TCL tests.
+#
+tcltest: testfixture.exe
 	@set PATH=$(LIBTCLPATH);$(PATH)
 	.\testfixture.exe $(TOP)\test\veryquick.test $(TESTOPTS)

+# Runs all the same tests cases as the "tcltest" target but uses
+# the testrunner.tcl script to run them in multiple cores
+# concurrently.
+testrunner:	testfixture.exe
+	.\testfixture.exe $(TOP)\test\testrunner.tcl
+
 smoketest:	$(TESTPROGS)
 	@set PATH=$(LIBTCLPATH);$(PATH)
 	.\testfixture.exe $(TOP)\test\main.test $(TESTOPTS)
@@ -1,7 +1,7 @@
 <h1 align="center">SQLite Source Repository</h1>

-This repository contains the complete source code for the 
-[SQLite database engine](https://sqlite.org/).  Some test scripts 
+This repository contains the complete source code for the
+[SQLite database engine](https://sqlite.org/).  Some test scripts
 are also included.  However, many other test scripts
 and most of the documentation are managed separately.

@@ -15,7 +15,7 @@ The [Fossil repository](https://sqlite.org/src/timeline) contains the urtext.
 If you are reading this on GitHub or some other Git repository or service,
 then you are looking at a mirror.  The names of check-ins and
 other artifacts in a Git mirror are different from the official
-names for those objects.  The offical names for check-ins are
+names for those objects.  The official names for check-ins are
 found in a footer on the check-in comment for authorized mirrors.
 The official check-in name can also be seen in the `manifest.uuid` file
 in the root of the tree.  Always use the official name, not  the
@@ -30,7 +30,7 @@ verify its integrity, there are hints on how to do that in the
 If you do not want to use Fossil, you can download tarballs or ZIP
 archives or [SQLite archives](https://sqlite.org/cli.html#sqlar) as follows:

-  *  Lastest trunk check-in as
+  *  Latest trunk check-in as
     [Tarball](https://www.sqlite.org/src/tarball/sqlite.tar.gz),
     [ZIP-archive](https://www.sqlite.org/src/zip/sqlite.zip), or
     [SQLite-archive](https://www.sqlite.org/src/sqlar/sqlite.sqlar).
@@ -47,11 +47,11 @@ archives or [SQLite archives](https://sqlite.org/cli.html#sqlar) as follows:
     then click on the "Tarball" or "ZIP Archive" links on the information
     page.

-If you do want to use Fossil to check out the source tree, 
+If you do want to use Fossil to check out the source tree,
 first install Fossil version 2.0 or later.
 (Source tarballs and precompiled binaries available
 [here](https://www.fossil-scm.org/fossil/uv/download.html).  Fossil is
-a stand-alone program.  To install, simply download or build the single 
+a stand-alone program.  To install, simply download or build the single
 executable file and put that file someplace on your $PATH.)
 Then run commands like this:

@@ -61,7 +61,7 @@ Then run commands like this:
        fossil open ~/Fossils/sqlite.fossil

 After setting up a repository using the steps above, you can always
-update to the lastest version using:
+update to the latest version using:

        fossil update trunk   ;# latest trunk check-in
        fossil update release ;# latest official release
@@ -136,7 +136,7 @@ the "tclsqlite.c" file which implements the
 extension and only later escaped to the wild as an independent library.)

 Test scripts and programs are found in the **test/** subdirectory.
-Addtional test code is found in other source repositories.
+Additional test code is found in other source repositories.
 See [How SQLite Is Tested](http://www.sqlite.org/testing.html) for
 additional information.

@@ -170,7 +170,7 @@ at just the right spots. Note that comment text in the sqlite3.h file is
 used to generate much of the SQLite API documentation.  The Tcl scripts
 used to generate that documentation are in a separate source repository.

-The SQL language parser is **parse.c** which is generate from a grammar in
+The SQL language parser is **parse.c** which is generated from a grammar in
 the src/parse.y file.  The conversion of "parse.y" into "parse.c" is done
 by the [lemon](./doc/lemon.html) LALR(1) parser generator.  The source code
 for lemon is at tool/lemon.c.  Lemon uses the tool/lempar.c file as a
@@ -180,7 +180,7 @@ generates parse.c.

 The **opcodes.h** header file contains macros that define the numbers
 corresponding to opcodes in the "VDBE" virtual machine.  The opcodes.h
-file is generated by the scanning the src/vdbe.c source file.  The
+file is generated by scanning the src/vdbe.c source file.  The
 Tcl script at ./mkopcodeh.tcl does this scan and generates opcodes.h.
 A second Tcl script, ./mkopcodec.tcl, then scans opcodes.h to generate
 the **opcodes.c** source file, which contains a reverse mapping from
@@ -237,7 +237,7 @@ prepared statements, the description of
 [how transactions work](http://www.sqlite.org/atomiccommit.html), and
 the [overview of the query planner](http://www.sqlite.org/optoverview.html).

-Years of effort have gone into optimizating SQLite, both
+Years of effort have gone into optimizing SQLite, both
 for small size and high performance.  And optimizations tend to result in
 complex code.  So there is a lot of complexity in the current SQLite
 implementation.  It will not be the easiest library in the world to hack.
@@ -294,11 +294,11 @@ Key files:
     building the "testfixture.exe" program.  The testfixture.exe program is
     an enhanced Tcl shell.  The testfixture.exe program runs scripts in the
     test/ folder to validate the core SQLite code.  The testfixture program
-     (and some other test programs too) is build and run when you type
+     (and some other test programs too) is built and run when you type
     "make test".

  *  **ext/misc/json1.c** - This file implements the various JSON functions
-     that are build into SQLite.
+     that are built into SQLite.

 There are many other source files.  Each has a succinct header comment that
 describes its purpose and role within the larger system.
@@ -307,11 +307,13 @@ describes its purpose and role within the larger system.
 ## Verifying Code Authenticity

 The `manifest` file at the root directory of the source tree
-contains either a SHA3-256 hash (for newer files) or a SHA1 hash (for 
+contains either a SHA3-256 hash (for newer files) or a SHA1 hash (for
 older files) for every source file in the repository.
-The SHA3-256 hash of the `manifest`
-file itself is the official name of the version of the source tree that you
-have. The `manifest.uuid` file should contain the SHA3-256 hash of the
+The name of the version of the entire source tree is just the
+SHA3-256 hash of the `manifest` file itself, possibly with the
+last line of that file omitted if the last line begins with
+"`# Remove this line`".
+The `manifest.uuid` file should contain the SHA3-256 hash of the
 `manifest` file. If all of the above hash comparisons are correct, then
 you can be confident that your source tree is authentic and unadulterated.

@@ -1 +1 @@
-3.37.0
+3.40.0
@@ -285,7 +285,6 @@ SQLITE3EXEPDB = /pdb:sqlite3sh.pdb
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_FTS3=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_RTREE=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_GEOPOLY=1
-OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_JSON1=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_STMTVTAB=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_DBPAGE_VTAB=1
 OPT_FEATURE_FLAGS = $(OPT_FEATURE_FLAGS) -DSQLITE_ENABLE_DBSTAT_VTAB=1
@@ -502,12 +501,12 @@ RCC = $(RC) -DSQLITE_OS_WIN=1 -I. -I$(TOP) $(RCOPTS) $(RCCOPTS)
 #
 !IF $(USE_STDCALL)!=0 || $(FOR_WIN10)!=0
 !IF "$(PLATFORM)"=="x86"
-CORE_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
-SHELL_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+CORE_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+SHELL_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
 !ELSE
 !IFNDEF PLATFORM
-CORE_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
-SHELL_CCONV_OPTS = -Gz -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+CORE_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
+SHELL_CCONV_OPTS = -Gz -guard:cf -DSQLITE_CDECL=__cdecl -DSQLITE_APICALL=__stdcall -DSQLITE_CALLBACK=__stdcall -DSQLITE_SYSAPI=__stdcall
 !ELSE
 CORE_CCONV_OPTS =
 SHELL_CCONV_OPTS =
@@ -105,7 +105,7 @@ may be specified in this manner as some require the amalgamation to be built
 with them enabled (see http://www.sqlite.org/compile.html). For example, the
 following will work:

-  "OPTS=-DSQLITE_ENABLE_STAT4=1 -DSQLITE_ENABLE_JSON1=1"
+  "OPTS=-DSQLITE_ENABLE_STAT4=1 -DSQLITE_OMIT_JSON=1"

 However, the following will not compile unless the amalgamation was built
 with it enabled:
@@ -173,21 +173,6 @@ else
 fi
 #-----------------------------------------------------------------------

-#-----------------------------------------------------------------------
-#   --enable-json1
-#
-AC_ARG_ENABLE(json1, [AS_HELP_STRING(
-  [--enable-json1], [include json1 support [default=yes]])], 
-  [],[enable_json1=yes])
-AC_MSG_CHECKING([JSON functions])
-if test x"$enable_json1" = "xyes"; then
-  BUILD_CFLAGS="$BUILD_CFLAGS -DSQLITE_ENABLE_JSON1"
-  AC_MSG_RESULT([enabled])
-else
-  AC_MSG_RESULT([disabled])
-fi
-#-----------------------------------------------------------------------
-
 #-----------------------------------------------------------------------
 #   --enable-rtree
 #
@@ -11,8 +11,6 @@
 #
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-#
-# RCS: @(#) $Id: Makefile.in,v 1.59 2005/07/26 19:17:02 mdejong Exp $

 #========================================================================
 # Add additional lines to handle any additional AC_SUBST cases that
@@ -60,6 +58,8 @@ PKG_HEADERS	= @PKG_HEADERS@
 #========================================================================

 PKG_LIB_FILE	= @PKG_LIB_FILE@
+PKG_LIB_FILE8	= @PKG_LIB_FILE8@
+PKG_LIB_FILE9	= @PKG_LIB_FILE9@
 PKG_STUB_LIB_FILE = @PKG_STUB_LIB_FILE@

 lib_BINARIES	= $(PKG_LIB_FILE)
@@ -73,10 +73,11 @@ exec_prefix	= @exec_prefix@

 bindir		= @bindir@
 libdir		= @libdir@
+includedir	= @includedir@
 datarootdir	= @datarootdir@
+runstatedir	= @runstatedir@
 datadir		= @datadir@
 mandir		= @mandir@
-includedir	= @includedir@

 DESTDIR		=

@@ -85,24 +86,25 @@ pkgdatadir	= $(datadir)/$(PKG_DIR)
 pkglibdir	= $(libdir)/$(PKG_DIR)
 pkgincludedir	= $(includedir)/$(PKG_DIR)

-top_builddir	= .
+top_builddir	= @abs_top_builddir@

-INSTALL		= @INSTALL@
-INSTALL_PROGRAM	= @INSTALL_PROGRAM@
+INSTALL_OPTIONS	=
+INSTALL		= @INSTALL@ $(INSTALL_OPTIONS)
+INSTALL_DATA_DIR = @INSTALL_DATA_DIR@
 INSTALL_DATA	= @INSTALL_DATA@
+INSTALL_PROGRAM	= @INSTALL_PROGRAM@
 INSTALL_SCRIPT	= @INSTALL_SCRIPT@
+INSTALL_LIBRARY	= @INSTALL_LIBRARY@

 PACKAGE_NAME	= @PACKAGE_NAME@
 PACKAGE_VERSION	= @PACKAGE_VERSION@
 CC		= @CC@
+CCLD		= @CCLD@
 CFLAGS_DEFAULT	= @CFLAGS_DEFAULT@
 CFLAGS_WARNING	= @CFLAGS_WARNING@
-CLEANFILES	= @CLEANFILES@
 EXEEXT		= @EXEEXT@
 LDFLAGS_DEFAULT	= @LDFLAGS_DEFAULT@
 MAKE_LIB	= @MAKE_LIB@
-MAKE_SHARED_LIB	= @MAKE_SHARED_LIB@
-MAKE_STATIC_LIB	= @MAKE_STATIC_LIB@
 MAKE_STUB_LIB	= @MAKE_STUB_LIB@
 OBJEXT		= @OBJEXT@
 RANLIB		= @RANLIB@
@@ -117,8 +119,6 @@ TCL_SRC_DIR	= @TCL_SRC_DIR@
 #TK_BIN_DIR	= @TK_BIN_DIR@
 #TK_SRC_DIR	= @TK_SRC_DIR@

-# This is no longer necessary even for packages that use private Tcl headers
-#TCL_TOP_DIR_NATIVE	= @TCL_TOP_DIR_NATIVE@
 # Not used, but retained for reference of what libs Tcl required
 #TCL_LIBS	= @TCL_LIBS@

@@ -132,41 +132,52 @@ TCL_SRC_DIR	= @TCL_SRC_DIR@
 EXTRA_PATH	= $(top_builddir):$(TCL_BIN_DIR)
 #EXTRA_PATH	= $(top_builddir):$(TCL_BIN_DIR):$(TK_BIN_DIR)
 TCLLIBPATH	= $(top_builddir)
-TCLSH_ENV	= TCL_LIBRARY=`@CYGPATH@ $(TCL_SRC_DIR)/library` \
-		  @LD_LIBRARY_PATH_VAR@="$(EXTRA_PATH):$(@LD_LIBRARY_PATH_VAR@)" \
+TCLSH_ENV	= TCL_LIBRARY=`@CYGPATH@ $(TCL_SRC_DIR)/library`
+PKG_ENV		= @LD_LIBRARY_PATH_VAR@="$(EXTRA_PATH):$(@LD_LIBRARY_PATH_VAR@)" \
 		  PATH="$(EXTRA_PATH):$(PATH)" \
 		  TCLLIBPATH="$(TCLLIBPATH)"
-#		  TK_LIBRARY=`@CYGPATH@ $(TK_SRC_DIR)/library`

 TCLSH_PROG	= @TCLSH_PROG@
-TCLSH	= $(TCLSH_ENV) $(TCLSH_PROG)
+TCLSH		= $(TCLSH_ENV) $(PKG_ENV) $(TCLSH_PROG)

+#WISH_ENV	= TK_LIBRARY=`@CYGPATH@ $(TK_SRC_DIR)/library`
 #WISH_PROG	= @WISH_PROG@
-#WISH	= $(TCLSH_ENV) $(WISH_PROG)
-
+#WISH		= $(TCLSH_ENV) $(WISH_ENV) $(PKG_ENV) $(WISH_PROG)

 SHARED_BUILD	= @SHARED_BUILD@

-INCLUDES	= @PKG_INCLUDES@ @TCL_INCLUDES@ -I$(srcdir)/..
+INCLUDES	= @PKG_INCLUDES@ @TCL_INCLUDES@ -I. -I$(srcdir)/..
 #INCLUDES	= @PKG_INCLUDES@ @TCL_INCLUDES@ @TK_INCLUDES@ @TK_XINCLUDES@

 PKG_CFLAGS	= @PKG_CFLAGS@

 # TCL_DEFS is not strictly need here, but if you remove it, then you
-# must make sure that configure.in checks for the necessary components
+# must make sure that configure.ac checks for the necessary components
 # that your library may use.  TCL_DEFS can actually be a problem if
 # you do not compile with a similar machine setup as the Tcl core was
 # compiled with.
 #DEFS		= $(TCL_DEFS) @DEFS@ $(PKG_CFLAGS)
 DEFS		= @DEFS@ $(PKG_CFLAGS)

+# Move pkgIndex.tcl to 'BINARIES' var if it is generated in the Makefile
 CONFIG_CLEAN_FILES = Makefile pkgIndex.tcl
+CLEANFILES	= @CLEANFILES@

 CPPFLAGS	= @CPPFLAGS@
 LIBS		= @PKG_LIBS@ @LIBS@
 AR		= @AR@
 CFLAGS		= @CFLAGS@
-COMPILE		= $(CC) $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
+LDFLAGS		= @LDFLAGS@
+LDFLAGS_DEFAULT			= @LDFLAGS_DEFAULT@
+COMPILE		= $(CC) $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) \
+			  $(CFLAGS_DEFAULT) $(CFLAGS_WARNING) $(SHLIB_CFLAGS) $(CFLAGS)
+
+GDB		= gdb
+VALGRIND	= valgrind
+VALGRINDARGS	= --tool=memcheck --num-callers=8 --leak-resolution=high \
+		  --leak-check=yes --show-reachable=yes -v
+
+.SUFFIXES: .c .$(OBJEXT)

 #========================================================================
 # Start of user-definable TARGETS section
@@ -174,7 +185,7 @@ COMPILE		= $(CC) $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(C

 #========================================================================
 # TEA TARGETS.  Please note that the "libraries:" target refers to platform
-# independent files, and the "binaries:" target inclues executable programs and
+# independent files, and the "binaries:" target includes executable programs and
 # platform-dependent libraries.  Modify these targets so that they install
 # the various pieces of your package.  The make and install rules
 # for the BINARIES that you specified above have already been done.
@@ -193,7 +204,6 @@ binaries: $(BINARIES)

 libraries:

-
 #========================================================================
 # Your doc target should differentiate from doc builds (by the developer)
 # and doc installs (see install-doc), which just install the docs on the
@@ -216,11 +226,11 @@ install-binaries: binaries install-lib-binaries install-bin-binaries
 #========================================================================

 install-libraries: libraries
-	@mkdir -p $(DESTDIR)$(includedir)
+	@$(INSTALL_DATA_DIR) "$(DESTDIR)$(includedir)"
 	@echo "Installing header files in $(DESTDIR)$(includedir)"
 	@list='$(PKG_HEADERS)'; for i in $$list; do \
 	    echo "Installing $(srcdir)/$$i" ; \
-	    $(INSTALL_DATA) $(srcdir)/$$i $(DESTDIR)$(includedir) ; \
+	    $(INSTALL_DATA) $(srcdir)/$$i "$(DESTDIR)$(includedir)" ; \
 	done;

 #========================================================================
@@ -229,12 +239,11 @@ install-libraries: libraries
 #========================================================================

 install-doc: doc
-	@mkdir -p $(DESTDIR)$(mandir)/mann
+	@$(INSTALL_DATA_DIR) "$(DESTDIR)$(mandir)/mann"
 	@echo "Installing documentation in $(DESTDIR)$(mandir)"
 	@list='$(srcdir)/doc/*.n'; for i in $$list; do \
 	    echo "Installing $$i"; \
-	    rm -f $(DESTDIR)$(mandir)/mann/`basename $$i`; \
-	    $(INSTALL_DATA) $$i $(DESTDIR)$(mandir)/mann ; \
+	    $(INSTALL_DATA) $$i "$(DESTDIR)$(mandir)/mann" ; \
 	done

 test: binaries libraries
@@ -244,7 +253,21 @@ shell: binaries libraries
 	@$(TCLSH) $(SCRIPT)

 gdb:
-	$(TCLSH_ENV) gdb $(TCLSH_PROG) $(SCRIPT)
+	$(TCLSH_ENV) $(PKG_ENV) $(GDB) $(TCLSH_PROG) $(SCRIPT)
+
+gdb-test: binaries libraries
+	$(TCLSH_ENV) $(PKG_ENV) $(GDB) \
+	    --args $(TCLSH_PROG) `@CYGPATH@ $(srcdir)/tests/all.tcl` \
+	    $(TESTFLAGS) -singleproc 1 \
+	    -load "package ifneeded $(PACKAGE_NAME) $(PACKAGE_VERSION) \
+		[list load `@CYGPATH@ $(PKG_LIB_FILE)` [string totitle $(PACKAGE_NAME)]]"
+
+valgrind: binaries libraries
+	$(TCLSH_ENV) $(PKG_ENV) $(VALGRIND) $(VALGRINDARGS) $(TCLSH_PROG) \
+	    `@CYGPATH@ $(srcdir)/tests/all.tcl` $(TESTFLAGS)
+
+valgrindshell: binaries libraries
+	$(TCLSH_ENV) $(PKG_ENV) $(VALGRIND) $(VALGRINDARGS) $(TCLSH_PROG) $(SCRIPT)

 depend:

@@ -283,49 +306,70 @@ $(PKG_STUB_LIB_FILE): $(PKG_STUB_OBJECTS)
 # As necessary, add $(srcdir):$(srcdir)/compat:....
 #========================================================================

-VPATH = $(srcdir):$(srcdir)/generic:$(srcdir)/unix:$(srcdir)/win
+VPATH = $(srcdir):$(srcdir)/generic:$(srcdir)/unix:$(srcdir)/win:$(srcdir)/macosx

 .c.@OBJEXT@:
 	$(COMPILE) -c `@CYGPATH@ $<` -o $@

+tclsample.@OBJEXT@:	sampleUuid.h
+
+$(srcdir)/manifest.uuid:
+	printf "git-" >$(srcdir)/manifest.uuid
+	(cd $(srcdir); git rev-parse HEAD >>$(srcdir)/manifest.uuid || \
+	    (printf "svn-r" >$(srcdir)/manifest.uuid ; \
+	    svn info --show-item last-changed-revision >>$(srcdir)/manifest.uuid) || \
+	    printf "unknown" >$(srcdir)/manifest.uuid)
+
+sampleUuid.h:	$(srcdir)/manifest.uuid
+	echo "#define SAMPLE_VERSION_UUID \\" >$@
+	cat $(srcdir)/manifest.uuid >>$@
+	echo "" >>$@
+
 #========================================================================
 # Distribution creation
 # You may need to tweak this target to make it work correctly.
 #========================================================================

 #COMPRESS	= tar cvf $(PKG_DIR).tar $(PKG_DIR); compress $(PKG_DIR).tar
-COMPRESS	= gtar zcvf $(PKG_DIR).tar.gz $(PKG_DIR)
+COMPRESS	= tar zcvf $(PKG_DIR).tar.gz $(PKG_DIR)
 DIST_ROOT	= /tmp/dist
 DIST_DIR	= $(DIST_ROOT)/$(PKG_DIR)

+DIST_INSTALL_DATA	= CPPROG='cp -p' $(INSTALL) -m 644
+DIST_INSTALL_SCRIPT	= CPPROG='cp -p' $(INSTALL) -m 755
+
 dist-clean:
 	rm -rf $(DIST_DIR) $(DIST_ROOT)/$(PKG_DIR).tar.*

-dist: dist-clean
-	mkdir -p $(DIST_DIR)
-	cp -p $(srcdir)/README* $(srcdir)/license* \
-		$(srcdir)/aclocal.m4 $(srcdir)/configure $(srcdir)/*.in \
-		$(DIST_DIR)/
-	chmod 664 $(DIST_DIR)/Makefile.in $(DIST_DIR)/aclocal.m4
-	chmod 775 $(DIST_DIR)/configure $(DIST_DIR)/configure.in
+dist: dist-clean $(srcdir)/manifest.uuid
+	$(INSTALL_DATA_DIR) $(DIST_DIR)

-	for i in $(srcdir)/*.[ch]; do \
-	    if [ -f $$i ]; then \
-		cp -p $$i $(DIST_DIR)/ ; \
-	    fi; \
-	done;
+	# TEA files
+	$(DIST_INSTALL_DATA) $(srcdir)/Makefile.in \
+	    $(srcdir)/aclocal.m4 $(srcdir)/configure.ac \
+	    $(DIST_DIR)/
+	$(DIST_INSTALL_SCRIPT) $(srcdir)/configure $(DIST_DIR)/

-	mkdir $(DIST_DIR)/tclconfig
-	cp $(srcdir)/tclconfig/install-sh $(srcdir)/tclconfig/tcl.m4 \
-		$(DIST_DIR)/tclconfig/
-	chmod 664 $(DIST_DIR)/tclconfig/tcl.m4
-	chmod +x $(DIST_DIR)/tclconfig/install-sh
+	$(INSTALL_DATA_DIR) $(DIST_DIR)/tclconfig
+	$(DIST_INSTALL_DATA) $(srcdir)/tclconfig/README.txt \
+	    $(srcdir)/manifest.uuid \
+	    $(srcdir)/tclconfig/tcl.m4 $(srcdir)/tclconfig/install-sh \
+	    $(DIST_DIR)/tclconfig/

-	list='demos doc generic library mac tests unix win'; \
+	# Extension files
+	$(DIST_INSTALL_DATA) \
+	    $(srcdir)/ChangeLog \
+	    $(srcdir)/README.sha \
+	    $(srcdir)/license.terms \
+	    $(srcdir)/README \
+	    $(srcdir)/pkgIndex.tcl.in \
+	    $(DIST_DIR)/
+
+	list='demos doc generic library macosx tests unix win'; \
 	for p in $$list; do \
 	    if test -d $(srcdir)/$$p ; then \
-		mkdir $(DIST_DIR)/$$p; \
-		cp -p $(srcdir)/$$p/*.* $(DIST_DIR)/$$p/; \
+		$(INSTALL_DATA_DIR) $(DIST_DIR)/$$p; \
+		$(DIST_INSTALL_DATA) $(srcdir)/$$p/* $(DIST_DIR)/$$p/; \
 	    fi; \
 	done

@@ -337,10 +381,10 @@ dist: dist-clean

 #========================================================================
 # Don't modify the file to clean here.  Instead, set the "CLEANFILES"
-# variable in configure.in
+# variable in configure.ac
 #========================================================================

-clean:  
+clean:
 	-test -z "$(BINARIES)" || rm -f $(BINARIES)
 	-rm -f *.$(OBJEXT) core *.core
 	-test -z "$(CLEANFILES)" || rm -f $(CLEANFILES)
@@ -348,7 +392,7 @@ clean:
 distclean: clean
 	-rm -f *.tab.c
 	-rm -f $(CONFIG_CLEAN_FILES)
-	-rm -f config.h config.cache config.log config.status
+	-rm -f config.cache config.log config.status

 #========================================================================
 # Install binary object libraries.  On Windows this includes both .dll and
@@ -362,25 +406,17 @@ distclean: clean
 #========================================================================

 install-lib-binaries: binaries
-	@mkdir -p $(DESTDIR)$(pkglibdir)
+	@$(INSTALL_DATA_DIR) "$(DESTDIR)$(pkglibdir)"
 	@list='$(lib_BINARIES)'; for p in $$list; do \
 	  if test -f $$p; then \
-	    echo " $(INSTALL_PROGRAM) $$p $(DESTDIR)$(pkglibdir)/$$p"; \
-	    $(INSTALL_PROGRAM) $$p $(DESTDIR)$(pkglibdir)/$$p; \
-	    stub=`echo $$p|sed -e "s/.*\(stub\).*/\1/"`; \
-	    if test "x$$stub" = "xstub"; then \
-		echo " $(RANLIB_STUB) $(DESTDIR)$(pkglibdir)/$$p"; \
-		$(RANLIB_STUB) $(DESTDIR)$(pkglibdir)/$$p; \
-	    else \
-		echo " $(RANLIB) $(DESTDIR)$(pkglibdir)/$$p"; \
-		$(RANLIB) $(DESTDIR)$(pkglibdir)/$$p; \
-	    fi; \
+	    echo " $(INSTALL_LIBRARY) $$p $(DESTDIR)$(pkglibdir)/$$p"; \
+	    $(INSTALL_LIBRARY) $$p "$(DESTDIR)$(pkglibdir)/$$p"; \
 	    ext=`echo $$p|sed -e "s/.*\.//"`; \
 	    if test "x$$ext" = "xdll"; then \
 		lib=`basename $$p|sed -e 's/.[^.]*$$//'`.lib; \
 		if test -f $$lib; then \
 		    echo " $(INSTALL_DATA) $$lib $(DESTDIR)$(pkglibdir)/$$lib"; \
-	            $(INSTALL_DATA) $$lib $(DESTDIR)$(pkglibdir)/$$lib; \
+	            $(INSTALL_DATA) $$lib "$(DESTDIR)$(pkglibdir)/$$lib"; \
 		fi; \
 	    fi; \
 	  fi; \
@@ -389,12 +425,12 @@ install-lib-binaries: binaries
 	  if test -f $(srcdir)/$$p; then \
 	    destp=`basename $$p`; \
 	    echo " Install $$destp $(DESTDIR)$(pkglibdir)/$$destp"; \
-	    $(INSTALL_DATA) $(srcdir)/$$p $(DESTDIR)$(pkglibdir)/$$destp; \
+	    $(INSTALL_DATA) $(srcdir)/$$p "$(DESTDIR)$(pkglibdir)/$$destp"; \
 	  fi; \
 	done
 	@if test "x$(SHARED_BUILD)" = "x1"; then \
 	    echo " Install pkgIndex.tcl $(DESTDIR)$(pkglibdir)"; \
-	    $(INSTALL_DATA) pkgIndex.tcl $(DESTDIR)$(pkglibdir); \
+	    $(INSTALL_DATA) pkgIndex.tcl "$(DESTDIR)$(pkglibdir)"; \
 	fi

 #========================================================================
@@ -407,33 +443,32 @@ install-lib-binaries: binaries
 #========================================================================

 install-bin-binaries: binaries
-	@mkdir -p $(DESTDIR)$(bindir)
+	@$(INSTALL_DATA_DIR) "$(DESTDIR)$(bindir)"
 	@list='$(bin_BINARIES)'; for p in $$list; do \
 	  if test -f $$p; then \
 	    echo " $(INSTALL_PROGRAM) $$p $(DESTDIR)$(bindir)/$$p"; \
-	    $(INSTALL_PROGRAM) $$p $(DESTDIR)$(bindir)/$$p; \
+	    $(INSTALL_PROGRAM) $$p "$(DESTDIR)$(bindir)/$$p"; \
 	  fi; \
 	done

-.SUFFIXES: .c .$(OBJEXT)
-
 Makefile: $(srcdir)/Makefile.in  $(top_builddir)/config.status
 	cd $(top_builddir) \
 	  && CONFIG_FILES=$@ CONFIG_HEADERS= $(SHELL) ./config.status

 uninstall-binaries:
 	list='$(lib_BINARIES)'; for p in $$list; do \
-	  rm -f $(DESTDIR)$(pkglibdir)/$$p; \
+	  rm -f "$(DESTDIR)$(pkglibdir)/$$p"; \
 	done
 	list='$(PKG_TCL_SOURCES)'; for p in $$list; do \
 	  p=`basename $$p`; \
-	  rm -f $(DESTDIR)$(pkglibdir)/$$p; \
+	  rm -f "$(DESTDIR)$(pkglibdir)/$$p"; \
 	done
 	list='$(bin_BINARIES)'; for p in $$list; do \
-	  rm -f $(DESTDIR)$(bindir)/$$p; \
+	  rm -f "$(DESTDIR)$(bindir)/$$p"; \
 	done

 .PHONY: all binaries clean depend distclean doc install libraries test
+.PHONY: gdb gdb-test valgrind valgrindshell

 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.
@@ -2,11 +2,9 @@
 dnl	This file is an input file used by the GNU "autoconf" program to
 dnl	generate the file "configure", which is run during Tcl installation
 dnl	to configure the system for the local environment.
-#
-# RCS: @(#) $Id: configure.in,v 1.43 2005/07/26 19:17:05 mdejong Exp $

 #-----------------------------------------------------------------------
-# Sample configure.in for Tcl Extensions.  The only places you should
+# Sample configure.ac for Tcl Extensions.  The only places you should
 # need to modify this file are marked by the string __CHANGE__
 #-----------------------------------------------------------------------

@@ -17,9 +15,11 @@ dnl	to configure the system for the local environment.
 # This initializes the environment with PACKAGE_NAME and PACKAGE_VERSION
 # set as provided.  These will also be added as -D defs in your Makefile
 # so you can encode the package version directly into the source files.
+# This will also define a special symbol for Windows (BUILD_<PACKAGE_NAME>
+# so that we create the export library with the dll.
 #-----------------------------------------------------------------------

-AC_INIT([sqlite], [3.32.0])
+AC_INIT([sqlite],[3.40.0])

 #--------------------------------------------------------------------
 # Call TEA_INIT as the first TEA_ macro to set up initial vars.
@@ -27,7 +27,7 @@ AC_INIT([sqlite], [3.32.0])
 # as well as PKG_LIB_FILE and PKG_STUB_LIB_FILE.
 #--------------------------------------------------------------------

-TEA_INIT([3.9])
+TEA_INIT()

 AC_CONFIG_AUX_DIR(tclconfig)

@@ -55,8 +55,8 @@ TEA_PREFIX
 #-----------------------------------------------------------------------
 # Standard compiler checks.
 # This sets up CC by using the CC env var, or looks for gcc otherwise.
-# This also calls AC_PROG_CC, AC_PROG_INSTALL and a few others to create
-# the basic setup necessary to compile executables.
+# This also calls AC_PROG_CC and a few others to create the basic setup
+# necessary to compile executables.
 #-----------------------------------------------------------------------

 TEA_SETUP_COMPILER
@@ -73,11 +73,19 @@ TEA_SETUP_COMPILER

 TEA_ADD_SOURCES([tclsqlite3.c])
 TEA_ADD_HEADERS([])
-TEA_ADD_INCLUDES([-I\"`\${CYGPATH} \${srcdir}/generic`\"])
+TEA_ADD_INCLUDES([])
 TEA_ADD_LIBS([])
 TEA_ADD_CFLAGS([-DSQLITE_ENABLE_FTS3=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_FTS4=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_FTS5=1])
 TEA_ADD_CFLAGS([-DSQLITE_3_SUFFIX_ONLY=1])
 TEA_ADD_CFLAGS([-DSQLITE_ENABLE_RTREE=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_GEOPOLY=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_MATH_FUNCTIONS=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_DESERIALIZE=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_DBPAGE_VTAB=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_BYTECODE_VTAB=1])
+TEA_ADD_CFLAGS([-DSQLITE_ENABLE_DBSTAT_VTAB=1])
 TEA_ADD_STUB_SOURCES([])
 TEA_ADD_TCL_SOURCES([])

@@ -99,6 +107,31 @@ if test x$with_system_sqlite != xno; then
      LIBS="$LIBS -lsqlite3"])])
 fi

+#--------------------------------------------------------------------
+# __CHANGE__
+#
+# You can add more files to clean if your extension creates any extra
+# files by extending CLEANFILES.
+# Add pkgIndex.tcl if it is generated in the Makefile instead of ./configure
+# and change Makefile.in to move it from CONFIG_CLEAN_FILES to BINARIES var.
+#
+# A few miscellaneous platform-specific items:
+# TEA_ADD_* any platform specific compiler/build info here.
+#--------------------------------------------------------------------
+
+#CLEANFILES="$CLEANFILES pkgIndex.tcl"
+if test "${TEA_PLATFORM}" = "windows" ; then
+    # Ensure no empty if clauses
+    :
+    #TEA_ADD_SOURCES([win/winFile.c])
+    #TEA_ADD_INCLUDES([-I\"$(${CYGPATH} ${srcdir}/win)\"])
+else
+    # Ensure no empty else clauses
+    :
+    #TEA_ADD_SOURCES([unix/unixFile.c])
+    #TEA_ADD_LIBS([-lsuperfly])
+fi
+
 #--------------------------------------------------------------------
 # __CHANGE__
 # Choose which headers you need.  Extension authors should try very
@@ -151,28 +184,6 @@ TEA_CONFIG_CFLAGS

 TEA_ENABLE_SYMBOLS

-#--------------------------------------------------------------------
-# Everyone should be linking against the Tcl stub library.  If you
-# can't for some reason, remove this definition.  If you aren't using
-# stubs, you also need to modify the SHLIB_LD_LIBS setting below to
-# link against the non-stubbed Tcl library.  Add Tk too if necessary.
-#--------------------------------------------------------------------
-
-AC_DEFINE(USE_TCL_STUBS, 1, [Use Tcl stubs])
-#AC_DEFINE(USE_TK_STUBS, 1, [Use Tk stubs])
-
-
-#--------------------------------------------------------------------
-# Redefine fdatasync as fsync on systems that lack fdatasync
-#--------------------------------------------------------------------
-#
-#AC_CHECK_FUNC(fdatasync, , AC_DEFINE(fdatasync, fsync))
-# Check for library functions that SQLite can optionally use.
-AC_CHECK_FUNCS([fdatasync usleep fullfsync localtime_r gmtime_r])
-
-AC_FUNC_STRERROR_R
-
-
 #--------------------------------------------------------------------
 # This macro generates a line to use when building a library.  It
 # depends on values set by the TEA_ENABLE_SHARED, TEA_ENABLE_SYMBOLS,
@@ -193,9 +204,24 @@ TEA_PROG_TCLSH
 #TEA_PROG_WISH

 #--------------------------------------------------------------------
-# Finally, substitute all of the various values into the Makefile.
-# You may alternatively have a special pkgIndex.tcl.in or other files
-# which require substituting th AC variables in.  Include these here.
+# Setup a *Config.sh.in configuration file.
 #--------------------------------------------------------------------

-AC_OUTPUT([Makefile pkgIndex.tcl])
+#TEA_EXPORT_CONFIG([sample])
+#AC_SUBST(SAMPLE_VAR)
+
+#--------------------------------------------------------------------
+# Specify files to substitute AC variables in. You may alternatively
+# have a special pkgIndex.tcl.in or other files which require
+# substituting the AC variables in. Include these here.
+#--------------------------------------------------------------------
+
+AC_CONFIG_FILES([Makefile pkgIndex.tcl])
+#AC_CONFIG_FILES([sampleConfig.sh])
+
+#--------------------------------------------------------------------
+# Finally, substitute all of the various values into the files
+# specified with AC_CONFIG_FILES.
+#--------------------------------------------------------------------
+
+AC_OUTPUT
@@ -1,7 +1,10 @@
+# -*- tcl -*-
+# Tcl package index file, version 1.1
 #
-# Tcl package index file
-#
-# Note sqlite*3* init specifically
-#
-package ifneeded sqlite3 @PACKAGE_VERSION@ \
-    [list load [file join $dir @PKG_LIB_FILE@] Sqlite3]
+if {[package vsatisfies [package provide Tcl] 9.0-]} {
+    package ifneeded sqlite3 @PACKAGE_VERSION@ \
+	    [list load [file join $dir @PKG_LIB_FILE9@] sqlite3]
+} else {
+    package ifneeded sqlite3 @PACKAGE_VERSION@ \
+	    [list load [file join $dir @PKG_LIB_FILE8@] sqlite3]
+}
@@ -251,7 +251,18 @@ INCLUDES	= $(SQL_INCLUDES) $(TCL_INCLUDES) -I"$(WINDIR)" \
                  -I"$(GENERICDIR)" -I"$(ROOT)\.."
 BASE_CLFAGS	= $(cflags) $(cdebug) $(crt) $(INCLUDES) \
                  -DSQLITE_3_SUFFIX_ONLY=1 -DSQLITE_ENABLE_RTREE=1 \
-                  -DSQLITE_ENABLE_FTS3=1 -DSQLITE_OMIT_DEPRECATED=1
+                  -DSQLITE_ENABLE_FTS3=1 -DSQLITE_OMIT_DEPRECATED=1 \
+                  -DSQLITE_ENABLE_FTS4=1 \
+                  -DSQLITE_ENABLE_FTS5=1 \
+                  -DSQLITE_3_SUFFIX_ONLY=1 \
+                  -DSQLITE_ENABLE_RTREE=1 \
+                  -DSQLITE_ENABLE_GEOPOLY=1 \
+                  -DSQLITE_ENABLE_MATH_FUNCTIONS=1 \
+                  -DSQLITE_ENABLE_DESERIALIZE=1 \
+                  -DSQLITE_ENABLE_DBPAGE_VTAB=1 \
+                  -DSQLITE_ENABLE_BYTECODE_VTAB=1 \
+                  -DSQLITE_ENABLE_DBSTAT_VTAB=1 
+
 CON_CFLAGS	= $(cflags) $(cdebug) $(crt) -DCONSOLE -DSQLITE_ENABLE_FTS3=1
 TCL_CFLAGS	= -DBUILD_sqlite -DUSE_TCL_STUBS \
                  -DPACKAGE_VERSION="\"$(DOTVERSION)\"" $(BASE_CLFAGS) \
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for sqlite 3.37.0.
+# Generated by GNU Autoconf 2.69 for sqlite 3.40.0.
 #
 #
 # Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
@@ -726,8 +726,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='sqlite'
 PACKAGE_TARNAME='sqlite'
-PACKAGE_VERSION='3.37.0'
-PACKAGE_STRING='sqlite 3.37.0'
+PACKAGE_VERSION='3.40.0'
+PACKAGE_STRING='sqlite 3.40.0'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''

@@ -770,11 +770,11 @@ ac_includes_default="\
 ac_subst_vars='LTLIBOBJS
 LIBOBJS
 BUILD_CFLAGS
+AMALGAMATION_LINE_MACROS
 USE_GCOV
 OPT_FEATURE_FLAGS
 HAVE_ZLIB
 USE_AMALGAMATION
-AMALGAMATION_LINE_MACROS
 TARGET_DEBUG
 TARGET_HAVE_EDITLINE
 TARGET_HAVE_READLINE
@@ -903,16 +903,15 @@ with_readline_lib
 with_readline_inc
 enable_debug
 enable_amalgamation
-amalgamation_line_macros
 enable_load_extension
 enable_math
+enable_json
 enable_all
 enable_memsys5
 enable_memsys3
 enable_fts3
 enable_fts4
 enable_fts5
-enable_json1
 enable_update_limit
 enable_geopoly
 enable_rtree
@@ -1469,7 +1468,7 @@ if test "$ac_init_help" = "long"; then
  # Omit some internal or obsolete options to make the list less imposing.
  # This message is too long to be a string in the A/UX 3.1 sh.
  cat <<_ACEOF
-\`configure' configures sqlite 3.37.0 to adapt to many kinds of systems.
+\`configure' configures sqlite 3.40.0 to adapt to many kinds of systems.

 Usage: $0 [OPTION]... [VAR=VALUE]...

@@ -1534,7 +1533,7 @@ fi

 if test -n "$ac_init_help"; then
  case $ac_init_help in
-     short | recursive ) echo "Configuration of sqlite 3.37.0:";;
+     short | recursive ) echo "Configuration of sqlite 3.40.0:";;
   esac
  cat <<\_ACEOF

@@ -1561,13 +1560,13 @@ Optional Features:
  --disable-load-extension
                          Disable loading of external extensions
  --disable-math          Disable math functions
-  --enable-all            Enable FTS4, FTS5, Geopoly, JSON, RTree, Sessions
+  --disable-json          Disable JSON functions
+  --enable-all            Enable FTS4, FTS5, Geopoly, RTree, Sessions
  --enable-memsys5        Enable MEMSYS5
  --enable-memsys3        Enable MEMSYS3
  --enable-fts3           Enable the FTS3 extension
  --enable-fts4           Enable the FTS4 extension
  --enable-fts5           Enable the FTS5 extension
-  --enable-json1          Enable the JSON1 extension
  --enable-update-limit   Enable the UPDATE/DELETE LIMIT clause
  --enable-geopoly        Enable the GEOPOLY extension
  --enable-rtree          Enable the RTREE extension
@@ -1662,7 +1661,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
  cat <<\_ACEOF
-sqlite configure 3.37.0
+sqlite configure 3.40.0
 generated by GNU Autoconf 2.69

 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2081,7 +2080,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.

-It was created by sqlite $as_me 3.37.0, which was
+It was created by sqlite $as_me 3.40.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was

  $ $0 $@
@@ -3939,13 +3938,13 @@ if ${lt_cv_nm_interface+:} false; then :
 else
  lt_cv_nm_interface="BSD nm"
  echo "int some_variable = 0;" > conftest.$ac_ext
-  (eval echo "\"\$as_me:3940: $ac_compile\"" >&5)
+  (eval echo "\"\$as_me:3941: $ac_compile\"" >&5)
  (eval "$ac_compile" 2>conftest.err)
  cat conftest.err >&5
-  (eval echo "\"\$as_me:3943: $NM \\\"conftest.$ac_objext\\\"\"" >&5)
+  (eval echo "\"\$as_me:3944: $NM \\\"conftest.$ac_objext\\\"\"" >&5)
  (eval "$NM \"conftest.$ac_objext\"" 2>conftest.err > conftest.out)
  cat conftest.err >&5
-  (eval echo "\"\$as_me:3946: output\"" >&5)
+  (eval echo "\"\$as_me:3947: output\"" >&5)
  cat conftest.out >&5
  if $GREP 'External.*some_variable' conftest.out > /dev/null; then
    lt_cv_nm_interface="MS dumpbin"
@@ -5151,7 +5150,7 @@ ia64-*-hpux*)
  ;;
 *-*-irix6*)
  # Find out which ABI we are using.
-  echo '#line 5152 "configure"' > conftest.$ac_ext
+  echo '#line 5153 "configure"' > conftest.$ac_ext
  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
  (eval $ac_compile) 2>&5
  ac_status=$?
@@ -6676,11 +6675,11 @@ else
   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
   -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:6677: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:6678: $lt_compile\"" >&5)
   (eval "$lt_compile" 2>conftest.err)
   ac_status=$?
   cat conftest.err >&5
-   echo "$as_me:6681: \$? = $ac_status" >&5
+   echo "$as_me:6682: \$? = $ac_status" >&5
   if (exit $ac_status) && test -s "$ac_outfile"; then
     # The compiler can only warn and ignore the option if not recognized
     # So say no if there are warnings other than the usual output.
@@ -7015,11 +7014,11 @@ else
   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
   -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:7016: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:7017: $lt_compile\"" >&5)
   (eval "$lt_compile" 2>conftest.err)
   ac_status=$?
   cat conftest.err >&5
-   echo "$as_me:7020: \$? = $ac_status" >&5
+   echo "$as_me:7021: \$? = $ac_status" >&5
   if (exit $ac_status) && test -s "$ac_outfile"; then
     # The compiler can only warn and ignore the option if not recognized
     # So say no if there are warnings other than the usual output.
@@ -7120,11 +7119,11 @@ else
   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
   -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:7121: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:7122: $lt_compile\"" >&5)
   (eval "$lt_compile" 2>out/conftest.err)
   ac_status=$?
   cat out/conftest.err >&5
-   echo "$as_me:7125: \$? = $ac_status" >&5
+   echo "$as_me:7126: \$? = $ac_status" >&5
   if (exit $ac_status) && test -s out/conftest2.$ac_objext
   then
     # The compiler can only warn and ignore the option if not recognized
@@ -7175,11 +7174,11 @@ else
   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
   -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:7176: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:7177: $lt_compile\"" >&5)
   (eval "$lt_compile" 2>out/conftest.err)
   ac_status=$?
   cat out/conftest.err >&5
-   echo "$as_me:7180: \$? = $ac_status" >&5
+   echo "$as_me:7181: \$? = $ac_status" >&5
   if (exit $ac_status) && test -s out/conftest2.$ac_objext
   then
     # The compiler can only warn and ignore the option if not recognized
@@ -9555,7 +9554,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 9556 "configure"
+#line 9557 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@@ -9651,7 +9650,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 9652 "configure"
+#line 9653 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@@ -10307,13 +10306,6 @@ done
 #
 USE_AMALGAMATION=1

-#########
-# By default, amalgamation sqlite3.c will have #line directives.
-# This is a build option not shown by ./configure --help
-# To control it, use configure option: amalgamation_line_macros=?
-# where ? is no to suppress #line directives or yes to create them.
-AMALGAMATION_LINE_MACROS=--linemacros=0
-
 #########
 # See whether we can run specific tclsh versions known to work well;
 # if not, then we fall back to plain tclsh.
@@ -11284,19 +11276,6 @@ if test "${enable_amalgamation}" = "no" ; then
  USE_AMALGAMATION=0
 fi

-########
-# See whether --disable
-if test "${amalgamation_line_macros+set}" = set; then :
-  enableval=$amalgamation_line_macros;
-fi
-
-if test "${amalgamation_line_macros}" = "yes" ; then
-  AMALGAMATION_LINE_MACROS=--linemacros=1
-fi
-if test "${amalgamation_line_macros}" = "no" ; then
-  AMALGAMATION_LINE_MACROS=--linemacros=0
-fi
-

 #########
 # Look for zlib.  Only needed by extensions and by the sqlite3.exe shell
@@ -11518,6 +11497,24 @@ fi

 fi

+##########
+# Do we want to support JSON functions
+#
+# Check whether --enable-json was given.
+if test "${enable_json+set}" = set; then :
+  enableval=$enable_json;
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to support JSON functions" >&5
+$as_echo_n "checking whether to support JSON functions... " >&6; }
+if test "$enable_json" = "no"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+  OPT_FEATURE_FLAGS="${OPT_FEATURE_FLAGS} -DSQLITE_OMIT_JSON"
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+fi

 ########
 # The --enable-all argument is short-hand to enable
@@ -11722,24 +11719,6 @@ else
 $as_echo "no" >&6; }
 fi

-#########
-# See whether we should enable JSON1
-# Check whether --enable-json1 was given.
-if test "${enable_json1+set}" = set; then :
-  enableval=$enable_json1;
-fi
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to support JSON" >&5
-$as_echo_n "checking whether to support JSON... " >&6; }
-if test "${enable_json1}" = "yes" -o "${enable_all}" = "yes" ; then
-  OPT_FEATURE_FLAGS="${OPT_FEATURE_FLAGS} -DSQLITE_ENABLE_JSON1"
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
-
 #########
 # See whether we should enable the LIMIT clause on UPDATE and DELETE
 # statements.
@@ -11882,6 +11861,17 @@ else
 fi


+#########
+# Enable/disabled amalagamation line macros
+########
+AMALGAMATION_LINE_MACROS=--linemacros=0
+if test "${amalgamation_line_macros}" = "yes" ; then
+  AMALGAMATION_LINE_MACROS=--linemacros=1
+fi
+if test "${amalgamation_line_macros}" = "no" ; then
+  AMALGAMATION_LINE_MACROS=--linemacros=0
+fi
+

 #########
 # Output the config header
@@ -12400,7 +12390,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by sqlite $as_me 3.37.0, which was
+This file was extended by sqlite $as_me 3.40.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was

  CONFIG_FILES    = $CONFIG_FILES
@@ -12466,7 +12456,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-sqlite config.status 3.37.0
+sqlite config.status 3.40.0
 configured by $0, generated by GNU Autoconf 2.69,
  with options \\"\$ac_cs_config\\"

@@ -605,12 +605,24 @@ else
  AC_SEARCH_LIBS(ceil, m)
 fi

+##########
+# Do we want to support JSON functions
+#
+AC_ARG_ENABLE(json, 
+AC_HELP_STRING([--disable-json],[Disable JSON functions]))
+AC_MSG_CHECKING([whether to support JSON functions])
+if test "$enable_json" = "no"; then
+  AC_MSG_RESULT([no])
+  OPT_FEATURE_FLAGS="${OPT_FEATURE_FLAGS} -DSQLITE_OMIT_JSON"
+else
+  AC_MSG_RESULT([yes])
+fi

 ########
 # The --enable-all argument is short-hand to enable
 # multiple extensions.
 AC_ARG_ENABLE(all, AC_HELP_STRING([--enable-all],
-      [Enable FTS4, FTS5, Geopoly, JSON, RTree, Sessions]))
+      [Enable FTS4, FTS5, Geopoly, RTree, Sessions]))

 ##########
 # Do we want to support memsys3 and/or memsys5
@@ -666,17 +678,6 @@ else
  AC_MSG_RESULT([no])
 fi

-#########
-# See whether we should enable JSON1
-AC_ARG_ENABLE(json1, AC_HELP_STRING([--enable-json1],[Enable the JSON1 extension]))
-AC_MSG_CHECKING([whether to support JSON])
-if test "${enable_json1}" = "yes" -o "${enable_all}" = "yes" ; then
-  OPT_FEATURE_FLAGS="${OPT_FEATURE_FLAGS} -DSQLITE_ENABLE_JSON1"
-  AC_MSG_RESULT([yes])
-else
-  AC_MSG_RESULT([no])
-fi
-
 #########
 # See whether we should enable the LIMIT clause on UPDATE and DELETE
 # statements.
@@ -791,6 +792,17 @@ else
 fi
 AC_SUBST(USE_GCOV)

+#########
+# Enable/disabled amalagamation line macros
+########
+AMALGAMATION_LINE_MACROS=--linemacros=0
+if test "${amalgamation_line_macros}" = "yes" ; then
+  AMALGAMATION_LINE_MACROS=--linemacros=1
+fi
+if test "${amalgamation_line_macros}" = "no" ; then
+  AMALGAMATION_LINE_MACROS=--linemacros=0
+fi
+AC_SUBST(AMALGAMATION_LINE_MACROS)

 #########
 # Output the config header
@@ -0,0 +1,144 @@
+# JSON Functions Enhancements (2022)
+
+This document summaries enhancements to the SQLite JSON support added in
+early 2022.
+
+## 1.0 Change summary:
+
+  1.  New **->** and **->>** operators that work like MySQL and PostgreSQL (PG).
+  2.  JSON functions are built-in rather than being an extension.  They
+      are included by default, but can be omitted using the
+      -DSQLITE_OMIT_JSON compile-time option.
+
+
+## 2.0 New operators **->** and **->>**
+
+The SQLite language adds two new binary operators **->** and **->>**.
+Both operators are similar to json_extract().  The left operand is
+JSON and the right operand is a JSON path expression (possibly abbreviated
+for compatibility with PG - see below).  So they are similar to a
+two-argument call to json_extract().
+
+The difference between -> and ->> (and json_extract()) is as follows:
+
+  *  The -> operator always returns JSON.
+
+  *  The ->> operator converts the answer into a primitive SQL datatype
+     such as TEXT, INTEGER, REAL, or NULL.  If a JSON object or array
+     is selected, that object or array is rendered as text.  If a JSON
+     value is selected, that value is converted into its corresponding
+     SQL type
+
+  *  The json_extract() interface returns JSON when a JSON object or
+     array is selected, or a primitive SQL datatype when a JSON value
+     is selected.  This is different from MySQL, in which json_extract()
+     always returns JSON, but the difference is retained because it has
+     worked that way for 6 years and changing it now would likely break
+     a lot of legacy code.
+
+In MySQL and PG, the ->> operator always returns TEXT (or NULL) and never
+INTEGER or REAL.  This is due to limitations in the type handling capabilities
+of those systems.  In MySQL and PG, the result type a function or operator
+may only depend on the type of its arguments, never the value of its arguments.
+But the underlying JSON type depends on the value of the JSON path
+expression, not the type of the JSON path expression (which is always TEXT).
+Hence, the result type of ->> in MySQL and PG is unable to vary according
+to the type of the JSON value being extracted.
+
+The type system in SQLite is more general.  Functions in SQLite are able
+to return different datatypes depending on the value of their arguments.
+So the ->> operator in SQLite is able to return TEXT, INTEGER, REAL, or NULL
+depending on the JSON type of the value being extracted.  This means that
+the behavior of the ->> is slightly different in SQLite versus MySQL and PG
+in that it will sometimes return INTEGER and REAL values, depending on its
+inputs.  It is possible to implement the ->> operator in SQLite so that it
+always operates exactly like MySQL and PG and always returns TEXT or NULL,
+but I have been unable to think of any situations where returning the
+actual JSON value this would cause problems, so I'm including the enhanced
+functionality in SQLite.
+
+The table below attempts to summarize the differences between the
+-> and ->> operators and the json_extract() function, for SQLite, MySQL,
+and PG.  JSON values are shown using their SQL text representation but
+in a bold font.
+
+
+<table border=1 cellpadding=5 cellspacing=0>
+<tr><th>JSON<th>PATH<th>-&gt; operator<br>(all)<th>-&gt;&gt; operator<br>(MySQL/PG)
+    <th>-&gt;&gt; operator<br>(SQLite)<th>json_extract()<br>(SQLite)
+<tr><td> **'{"a":123}'**     <td>'$.a'<td> **'123'**     <td> '123'          <td> 123           <td> 123
+<tr><td> **'{"a":4.5}'**     <td>'$.a'<td> **'4.5'**     <td> '4.5'          <td> 4.5           <td> 4.5
+<tr><td> **'{"a":"xyz"}'**   <td>'$.a'<td> **'"xyz"'**   <td> 'xyz'          <td> 'xyz'         <td> 'xyz'
+<tr><td> **'{"a":null}'**    <td>'$.a'<td> **'null'**    <td> NULL           <td> NULL          <td> NULL
+<tr><td> **'{"a":[6,7,8]}'** <td>'$.a'<td> **'[6,7,8]'** <td> '[6,7,8]'      <td> '[6,7,8]'     <td> **'[6,7,8]'**
+<tr><td> **'{"a":{"x":9}}'** <td>'$.a'<td> **'{"x":9}'** <td> '{"x":9}'      <td> '{"x":9}'     <td> **'{"x":9}'**
+<tr><td> **'{"b":999}'**     <td>'$.a'<td> NULL          <td> NULL           <td> NULL          <td> NULL
+</table>
+
+Important points about the table above:
+
+  *  The -> operator always returns either JSON or NULL.
+
+  *  The ->> operator never returns JSON.  It always returns TEXT or NULL, or in the
+     case of SQLite, INTEGER or REAL.
+
+  *  The MySQL json_extract() function works exactly the same
+     as the MySQL -> operator.
+
+  *  The SQLite json_extract() operator works like -> for JSON objects and
+     arrays, and like ->> for JSON values.
+
+  *  The -> operator works the same for all systems.
+
+  *  The only difference in ->> between SQLite and other systems is that
+     when the JSON value is numeric, SQLite returns a numeric SQL value,
+     whereas the other systems return a text representation of the numeric
+     value.
+
+### 2.1 Abbreviated JSON path expressions for PG compatibility
+
+The table above always shows the full JSON path expression: '$.a'.  But
+PG does not accept this syntax.  PG only allows a single JSON object label
+name or a single integer array index.  In order to provide compatibility
+with PG, The -> and ->> operators in SQLite are extended to also support
+a JSON object label or an integer array index for the right-hand side
+operand, in addition to a full JSON path expression.
+
+Thus, a -> or ->> operator that works on MySQL will work in
+SQLite.  And a -> or ->> operator that works in PG will work in SQLite.
+But because SQLite supports the union of the disjoint capabilities of
+MySQL and PG, there will always be -> and ->> operators that work in
+SQLite that do not work in one of MySQL and PG.  This is an unavoidable
+consequence of the different syntax for -> and ->> in MySQL and PG.
+
+In the following table, assume that "value1" is a JSON object and
+"value2" is a JSON array.
+
+<table border=1 cellpadding=5 cellspacing=0>
+<tr><th>SQL expression     <th>Works in MySQL?<th>Works in PG?<th>Works in SQLite
+<tr><td>value1-&gt;'$.a'   <td> yes           <td>  no        <td> yes
+<tr><td>value1-&gt;'a'     <td> no            <td>  yes       <td> yes
+<tr><td>value2-&gt;'$[2]'  <td> yes           <td>  no        <td> yes
+<tr><td>value2-&gt;2       <td> no            <td>  yes       <td> yes
+</table>
+
+The abbreviated JSON path expressions only work for the -> and ->> operators
+in SQLite.  The json_extract() function, and all other built-in SQLite
+JSON functions, continue to require complete JSON path expressions for their
+PATH arguments.
+
+## 3.0 JSON moved into the core
+
+The JSON interface is now moved into the SQLite core.
+
+When originally written in 2015, the JSON functions were an extension
+that could be optionally included at compile-time, or loaded at run-time.
+The implementation was in a source file named ext/misc/json1.c in the
+source tree.  JSON functions were only compiled in if the
+-DSQLITE_ENABLE_JSON1 compile-time option was used.
+
+After these enhancements, the JSON functions are now built-ins.
+The source file that implements the JSON functions is moved to src/json.c.
+No special compile-time options are needed to load JSON into the build.
+Instead, there is a new -DSQLITE_OMIT_JSON compile-time option to leave
+them out.
@@ -662,6 +662,7 @@ static int idxRegisterVtab(sqlite3expert *p){
    0,                            /* xRelease */
    0,                            /* xRollbackTo */
    0,                            /* xShadowName */
+    0                             /* xShadowName2 */
  };

  return sqlite3_create_module(p->dbv, "expert", &expertModule, (void*)p);
@@ -697,17 +698,25 @@ static int idxGetTableInfo(
 ){
  sqlite3_stmt *p1 = 0;
  int nCol = 0;
-  int nTab = STRLEN(zTab);
-  int nByte = sizeof(IdxTable) + nTab + 1;
+  int nTab;
+  int nByte;
  IdxTable *pNew = 0;
  int rc, rc2;
  char *pCsr = 0;
  int nPk = 0;

+  *ppOut = 0;
+  if( zTab==0 ) return SQLITE_ERROR;
+  nTab = STRLEN(zTab);
+  nByte = sizeof(IdxTable) + nTab + 1;
  rc = idxPrintfPrepareStmt(db, &p1, pzErrmsg, "PRAGMA table_xinfo=%Q", zTab);
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
    const char *zCol = (const char*)sqlite3_column_text(p1, 1);
    const char *zColSeq = 0;
+    if( zCol==0 ){
+      rc = SQLITE_ERROR;
+      break;
+    }
    nByte += 1 + STRLEN(zCol);
    rc = sqlite3_table_column_metadata(
        db, "main", zTab, zCol, 0, &zColSeq, 0, 0, 0
@@ -734,7 +743,9 @@ static int idxGetTableInfo(
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
    const char *zCol = (const char*)sqlite3_column_text(p1, 1);
    const char *zColSeq = 0;
-    int nCopy = STRLEN(zCol) + 1;
+    int nCopy;
+    if( zCol==0 ) continue;
+    nCopy = STRLEN(zCol) + 1;
    pNew->aCol[nCol].zName = pCsr;
    pNew->aCol[nCol].iPk = (sqlite3_column_int(p1, 5)==1 && nPk==1);
    memcpy(pCsr, zCol, nCopy);
@@ -886,6 +897,7 @@ static int idxFindCompatible(
    IdxConstraint *pT = pTail;
    sqlite3_stmt *pInfo = 0;
    const char *zIdx = (const char*)sqlite3_column_text(pIdxList, 1);
+    if( zIdx==0 ) continue;

    /* Zero the IdxConstraint.bFlag values in the pEq list */
    for(pIter=pEq; pIter; pIter=pIter->pLink) pIter->bFlag = 0;
@@ -1168,7 +1180,7 @@ static void idxWriteFree(IdxWrite *pTab){
 ** runs all the queries to see which indexes they prefer, and populates
 ** IdxStatement.zIdx and IdxStatement.zEQP with the results.
 */
-int idxFindIndexes(
+static int idxFindIndexes(
  sqlite3expert *p,
  char **pzErr                         /* OUT: Error message (sqlite3_malloc) */
 ){
@@ -1297,6 +1309,7 @@ static int idxProcessOneTrigger(
  rc = idxPrintfPrepareStmt(p->db, &pSelect, pzErr, zSql, zTab, zTab);
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSelect) ){
    const char *zCreate = (const char*)sqlite3_column_text(pSelect, 0);
+    if( zCreate==0 ) continue;
    rc = sqlite3_exec(p->dbv, zCreate, 0, 0, pzErr);
  }
  idxFinalize(&rc, pSelect);
@@ -1399,8 +1412,9 @@ static int idxCreateVtabSchema(sqlite3expert *p, char **pzErrmsg){
    const char *zName = (const char*)sqlite3_column_text(pSchema, 1);
    const char *zSql = (const char*)sqlite3_column_text(pSchema, 2);

+    if( zType==0 || zName==0 ) continue;
    if( zType[0]=='v' || zType[1]=='r' ){
-      rc = sqlite3_exec(p->dbv, zSql, 0, 0, pzErrmsg);
+      if( zSql ) rc = sqlite3_exec(p->dbv, zSql, 0, 0, pzErrmsg);
    }else{
      IdxTable *pTab;
      rc = idxGetTableInfo(p->db, zName, &pTab, pzErrmsg);
@@ -1537,6 +1551,7 @@ static void idxRemFunc(
    case SQLITE_BLOB:
    case SQLITE_TEXT: {
      int nByte = sqlite3_value_bytes(argv[1]);
+      const void *pData = 0;
      if( nByte>pSlot->nByte ){
        char *zNew = (char*)sqlite3_realloc(pSlot->z, nByte*2);
        if( zNew==0 ){
@@ -1548,9 +1563,11 @@ static void idxRemFunc(
      }
      pSlot->n = nByte;
      if( pSlot->eType==SQLITE_BLOB ){
-        memcpy(pSlot->z, sqlite3_value_blob(argv[1]), nByte);
+        pData = sqlite3_value_blob(argv[1]);
+        if( pData ) memcpy(pSlot->z, pData, nByte);
      }else{
-        memcpy(pSlot->z, sqlite3_value_text(argv[1]), nByte);
+        pData = sqlite3_value_text(argv[1]);
+        memcpy(pSlot->z, pData, nByte);
      }
      break;
    }
@@ -1761,6 +1778,7 @@ static int idxPopulateStat1(sqlite3expert *p, char **pzErr){
    i64 iRowid = sqlite3_column_int64(pAllIndex, 0);
    const char *zTab = (const char*)sqlite3_column_text(pAllIndex, 1);
    const char *zIdx = (const char*)sqlite3_column_text(pAllIndex, 2);
+    if( zTab==0 || zIdx==0 ) continue;
    if( p->iSample<100 && iPrev!=iRowid ){
      samplectx.target = (double)p->iSample / 100.0;
      samplectx.iTarget = p->iSample;
@@ -1827,14 +1845,14 @@ sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErrmsg){

  /* Copy the entire schema of database [db] into [dbm]. */
  if( rc==SQLITE_OK ){
-    sqlite3_stmt *pSql;
+    sqlite3_stmt *pSql = 0;
    rc = idxPrintfPrepareStmt(pNew->db, &pSql, pzErrmsg, 
        "SELECT sql FROM sqlite_schema WHERE name NOT LIKE 'sqlite_%%'"
        " AND sql NOT LIKE 'CREATE VIRTUAL %%'"
    );
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSql) ){
      const char *zSql = (const char*)sqlite3_column_text(pSql, 0);
-      rc = sqlite3_exec(pNew->dbm, zSql, 0, 0, pzErrmsg);
+      if( zSql ) rc = sqlite3_exec(pNew->dbm, zSql, 0, 0, pzErrmsg);
    }
    idxFinalize(&rc, pSql);
  }
@@ -0,0 +1,7 @@
+_fiddle_exec
+_fiddle_interrupt
+_fiddle_experiment
+_fiddle_the_db
+_fiddle_db_arg
+_fiddle_db_filename
+_fiddle_reset_db
@@ -0,0 +1,51 @@
+_sqlite3_bind_blob
+_sqlite3_bind_double
+_sqlite3_bind_int
+_sqlite3_bind_int64
+_sqlite3_bind_null
+_sqlite3_bind_parameter_count
+_sqlite3_bind_parameter_index
+_sqlite3_bind_text
+_sqlite3_changes
+_sqlite3_clear_bindings
+_sqlite3_close_v2
+_sqlite3_column_blob
+_sqlite3_column_bytes
+_sqlite3_column_count
+_sqlite3_column_count
+_sqlite3_column_double
+_sqlite3_column_int
+_sqlite3_column_int64
+_sqlite3_column_name
+_sqlite3_column_text
+_sqlite3_column_type
+_sqlite3_compileoption_get
+_sqlite3_compileoption_used
+_sqlite3_create_function_v2
+_sqlite3_data_count
+_sqlite3_db_filename
+_sqlite3_errmsg
+_sqlite3_exec
+_sqlite3_finalize
+_sqlite3_interrupt
+_sqlite3_libversion
+_sqlite3_open
+_sqlite3_open_v2
+_sqlite3_prepare_v2
+_sqlite3_prepare_v2
+_sqlite3_reset
+_sqlite3_result_blob
+_sqlite3_result_double
+_sqlite3_result_error
+_sqlite3_result_int
+_sqlite3_result_null
+_sqlite3_result_text
+_sqlite3_sourceid
+_sqlite3_sql
+_sqlite3_step
+_sqlite3_value_blob
+_sqlite3_value_bytes
+_sqlite3_value_double
+_sqlite3_value_text
+_sqlite3_value_type
+_free
@@ -0,0 +1,14 @@
+ALLOC_NORMAL
+FS
+UTF8ToString
+addFunction
+allocate
+allocateUTF8OnStack
+ccall
+cwrap
+getValue
+removeFunction
+setValue
+stackAlloc
+stackRestore
+stackSave
@@ -0,0 +1,34 @@
+# This GNU makefile exists primarily to simplify/speed up development
+# from emacs. It is not part of the canonical build process.
+default:
+	$(MAKE) -C ../.. wasm -e emcc_opt=-O0
+
+clean:
+	$(MAKE) -C ../../ clean-wasm
+
+fiddle_files = emscripten.css fiddle.html \
+             fiddle.js fiddle-module.js \
+             fiddle-module.wasm fiddle-worker.js \
+             $(wildcard *.wasm.gz) $(wildcard *.js.gz)
+
+# fiddle_remote is the remote destination for the fiddle app. It
+# must be a [user@]HOST:/path for rsync.
+# Note that the target "should probably" contain a symlink of
+# index.html -> fiddle.html.
+fiddle_remote ?=
+ifeq (,$(fiddle_remote))
+ifneq (,$(wildcard /home/stephan))
+  fiddle_remote = wh2:www/wh/sqlite3/.
+else ifneq (,$(wildcard /home/drh))
+  #fiddle_remote = if appropriate, add that user@host:/path here
+endif
+endif
+
+$(fiddle_files): default
+
+push-fiddle: $(fiddle_files)
+	@if [ x = "x$(fiddle_remote)" ]; then \
+		echo "fiddle_remote must be a [user@]HOST:/path for rsync"; \
+		exit 1; \
+	fi
+	rsync -va $(fiddle_files) $(fiddle_remote)
@@ -0,0 +1,144 @@
+/*
+  2022-05-22
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  This file contains bootstrapping code used by various test scripts
+  which live in this file's directory.
+*/
+(function(){
+    /* querySelectorAll() proxy */
+    const EAll = function(/*[element=document,] cssSelector*/){
+        return (arguments.length>1 ? arguments[0] : document)
+            .querySelectorAll(arguments[arguments.length-1]);
+    };
+    /* querySelector() proxy */
+    const E = function(/*[element=document,] cssSelector*/){
+        return (arguments.length>1 ? arguments[0] : document)
+            .querySelector(arguments[arguments.length-1]);
+    };
+
+    /**
+       Helpers for writing sqlite3-specific tests.
+    */
+    self/*window or worker*/.SqliteTestUtil = {
+        /** Running total of the number of tests run via
+            this API. */
+        counter: 0,
+        /**
+           If expr is a function, it is called and its result
+           is returned, coerced to a bool, else expr, coerced to
+           a bool, is returned.
+        */
+        toBool: function(expr){
+            return (expr instanceof Function) ? !!expr() : !!expr;
+        },
+        /** abort() if expr is false. If expr is a function, it
+            is called and its result is evaluated.
+        */
+        assert: function f(expr, msg){
+            if(!f._){
+                f._ = ('undefined'===typeof abort
+                       ? (msg)=>{throw new Error(msg)}
+                       : abort);
+            }
+            ++this.counter;
+            if(!this.toBool(expr)){
+                f._(msg || "Assertion failed.");
+            }
+            return this;
+        },
+        /** Identical to assert() but throws instead of calling
+            abort(). */
+        affirm: function(expr, msg){
+            ++this.counter;
+            if(!this.toBool(expr)) throw new Error(msg || "Affirmation failed.");
+            return this;
+        },
+        /** Calls f() and squelches any exception it throws. If it
+            does not throw, this function throws. */
+        mustThrow: function(f, msg){
+            ++this.counter;
+            let err;
+            try{ f(); } catch(e){err=e;}
+            if(!err) throw new Error(msg || "Expected exception.");
+            return this;
+        },
+        /** Throws if expr is truthy or expr is a function and expr()
+            returns truthy. */
+        throwIf: function(expr, msg){
+            ++this.counter;
+            if(this.toBool(expr)) throw new Error(msg || "throwIf() failed");
+            return this;
+        },
+        /** Throws if expr is falsy or expr is a function and expr()
+            returns falsy. */
+        throwUnless: function(expr, msg){
+            ++this.counter;
+            if(!this.toBool(expr)) throw new Error(msg || "throwUnless() failed");
+            return this;
+        }
+    };
+
+    
+    /**
+       This is a module object for use with the emscripten-installed
+       initSqlite3Module() factory function.
+    */
+    self.sqlite3TestModule = {
+        postRun: [
+            /* function(theModule){...} */
+        ],
+        //onRuntimeInitialized: function(){},
+        /* Proxy for C-side stdout output. */
+        print: function(){
+            console.log.apply(console, Array.prototype.slice.call(arguments));
+        },
+        /* Proxy for C-side stderr output. */
+        printErr: function(){
+            console.error.apply(console, Array.prototype.slice.call(arguments));
+        },
+        /**
+           Called by the module init bits to report loading
+           progress. It gets passed an empty argument when loading is
+           done (after onRuntimeInitialized() and any this.postRun
+           callbacks have been run).
+        */
+        setStatus: function f(text){
+            if(!f.last){
+                f.last = { text: '', step: 0 };
+                f.ui = {
+                    status: E('#module-status'),
+                    progress: E('#module-progress'),
+                    spinner: E('#module-spinner')
+                };
+            }
+            if(text === f.last.text) return;
+            f.last.text = text;
+            if(f.ui.progress){
+                f.ui.progress.value = f.last.step;
+                f.ui.progress.max = f.last.step + 1;
+            }
+            ++f.last.step;
+            if(text) {
+                f.ui.status.classList.remove('hidden');
+                f.ui.status.innerText = text;
+            }else{
+                if(f.ui.progress){
+                    f.ui.progress.remove();
+                    f.ui.spinner.remove();
+                    delete f.ui.progress;
+                    delete f.ui.spinner;
+                }
+                f.ui.status.classList.add('hidden');
+            }
+        }
+    };
+})(self/*window or worker*/);
@@ -0,0 +1,24 @@
+/* emcscript-related styling, used during the module load/intialization processes... */
+.emscripten { padding-right: 0; margin-left: auto; margin-right: auto; display: block; }
+div.emscripten { text-align: center; }
+div.emscripten_border { border: 1px solid black; }
+#module-spinner { overflow: visible; }
+#module-spinner > * {
+    margin-top: 1em;
+}
+.spinner {
+    height: 50px;
+    width: 50px;
+    margin: 0px auto;
+    animation: rotation 0.8s linear infinite;
+    border-left: 10px solid rgb(0,150,240);
+    border-right: 10px solid rgb(0,150,240);
+    border-bottom: 10px solid rgb(0,150,240);
+    border-top: 10px solid rgb(100,0,200);
+    border-radius: 100%;
+    background-color: rgb(200,100,250);
+}
+@keyframes rotation {
+    from {transform: rotate(0deg);}
+    to {transform: rotate(360deg);}
+}
@@ -0,0 +1,301 @@
+/*
+  2022-05-20
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  This is the JS Worker file for the sqlite3 fiddle app. It loads the
+  sqlite3 wasm module and offers access to the db via the Worker
+  message-passing interface.
+
+  Forewarning: this API is still very much Under Construction and
+  subject to any number of changes as experience reveals what those
+  need to be.
+
+  Because we can have only a single message handler, as opposed to an
+  arbitrary number of discrete event listeners like with DOM elements,
+  we have to define a lower-level message API. Messages abstractly
+  look like:
+
+  { type: string, data: type-specific value }
+
+  Where 'type' is used for dispatching and 'data' is a
+  'type'-dependent value.
+
+  The 'type' values expected by each side of the main/worker
+  connection vary. The types are described below but subject to
+  change at any time as this experiment evolves.
+
+  Workers-to-Main types
+
+  - stdout, stderr: indicate stdout/stderr output from the wasm
+    layer. The data property is the string of the output, noting
+    that the emscripten binding emits these one line at a time. Thus,
+    if a C-side puts() emits multiple lines in a single call, the JS
+    side will see that as multiple calls. Example:
+
+    {type:'stdout', data: 'Hi, world.'}
+
+  - module: Status text. This is intended to alert the main thread
+    about module loading status so that, e.g., the main thread can
+    update a progress widget and DTRT when the module is finished
+    loading and available for work. Status messages come in the form
+    
+    {type:'module', data:{
+        type:'status',
+        data: {text:string|null, step:1-based-integer}
+    }
+
+    with an incrementing step value for each subsequent message. When
+    the module loading is complete, a message with a text value of
+    null is posted.
+
+  - working: data='start'|'end'. Indicates that work is about to be
+    sent to the module or has just completed. This can be used, e.g.,
+    to disable UI elements which should not be activated while work
+    is pending. Example:
+
+    {type:'working', data:'start'}
+
+  Main-to-Worker types:
+
+  - shellExec: data=text to execute as if it had been entered in the
+    sqlite3 CLI shell app (as opposed to sqlite3_exec()). This event
+    causes the worker to emit a 'working' event (data='start') before
+    it starts and a 'working' event (data='end') when it finished. If
+    called while work is currently being executed it emits stderr
+    message instead of doing actual work, as the underlying db cannot
+    handle concurrent tasks. Example:
+
+    {type:'shellExec', data: 'select * from sqlite_master'}
+
+  - More TBD as the higher-level db layer develops.
+*/
+
+/*
+  Apparent browser(s) bug: console messages emitted may be duplicated
+  in the console, even though they're provably only run once. See:
+
+  https://stackoverflow.com/questions/49659464
+
+  Noting that it happens in Firefox as well as Chrome. Harmless but
+  annoying.
+*/
+"use strict";
+(function(){
+    /**
+       Posts a message in the form {type,data} unless passed more than 2
+       args, in which case it posts {type, data:[arg1...argN]}.
+    */
+    const wMsg = function(type,data){
+        postMessage({
+            type,
+            data: arguments.length<3
+                ? data
+                : Array.prototype.slice.call(arguments,1)
+        });
+    };
+
+    const stdout = function(){wMsg('stdout', Array.prototype.slice.call(arguments));};
+    const stderr = function(){wMsg('stderr', Array.prototype.slice.call(arguments));};
+
+    self.onerror = function(/*message, source, lineno, colno, error*/) {
+        const err = arguments[4];
+        if(err && 'ExitStatus'==err.name){
+            /* This is relevant for the sqlite3 shell binding but not the
+               lower-level binding. */
+            fiddleModule.isDead = true;
+            stderr("FATAL ERROR:", err.message);
+            stderr("Restarting the app requires reloading the page.");
+            wMsg('error', err);
+        }
+        console.error(err);
+        fiddleModule.setStatus('Exception thrown, see JavaScript console: '+err);
+    };
+
+    const Sqlite3Shell = {
+        /** Returns the name of the currently-opened db. */
+        dbFilename: function f(){
+            if(!f._) f._ = fiddleModule.cwrap('fiddle_db_filename', "string", ['string']);
+            return f._();
+        },
+        /**
+           Runs the given text through the shell as if it had been typed
+           in by a user. Fires a working/start event before it starts and
+           working/end event when it finishes.
+        */
+        exec: function f(sql){
+            if(!f._) f._ = fiddleModule.cwrap('fiddle_exec', null, ['string']);
+            if(fiddleModule.isDead){
+                stderr("shell module has exit()ed. Cannot run SQL.");
+                return;
+            }
+            wMsg('working','start');
+            try {
+                if(f._running){
+                    stderr('Cannot run multiple commands concurrently.');
+                }else{
+                    f._running = true;
+                    f._(sql);
+                }
+            } finally {
+                delete f._running;
+                wMsg('working','end');
+            }
+        },
+        resetDb: function f(){
+            if(!f._) f._ = fiddleModule.cwrap('fiddle_reset_db', null);
+            stdout("Resetting database.");
+            f._();
+            stdout("Reset",this.dbFilename());
+        },
+        /* Interrupt can't work: this Worker is tied up working, so won't get the
+           interrupt event which would be needed to perform the interrupt. */
+        interrupt: function f(){
+            if(!f._) f._ = fiddleModule.cwrap('fiddle_interrupt', null);
+            stdout("Requesting interrupt.");
+            f._();
+        }
+    };
+
+    self.onmessage = function f(ev){
+        ev = ev.data;
+        if(!f.cache){
+            f.cache = {
+                prevFilename: null
+            };
+        }
+        //console.debug("worker: onmessage.data",ev);
+        switch(ev.type){
+            case 'shellExec': Sqlite3Shell.exec(ev.data); return;
+            case 'db-reset': Sqlite3Shell.resetDb(); return;
+            case 'interrupt': Sqlite3Shell.interrupt(); return;
+                /** Triggers the export of the current db. Fires an
+                    event in the form:
+
+                    {type:'db-export',
+                    data:{
+                    filename: name of db,
+                    buffer: contents of the db file (Uint8Array),
+                    error: on error, a message string and no buffer property.
+                    }
+                    }
+                */
+            case 'db-export': {
+                const fn = Sqlite3Shell.dbFilename();
+                stdout("Exporting",fn+".");
+                const fn2 = fn ? fn.split(/[/\\]/).pop() : null;
+                try{
+                    if(!fn2) throw new Error("DB appears to be closed.");
+                    wMsg('db-export',{
+                        filename: fn2,
+                        buffer: fiddleModule.FS.readFile(fn, {encoding:"binary"})
+                    });
+                }catch(e){
+                    /* Post a failure message so that UI elements disabled
+                       during the export can be re-enabled. */
+                    wMsg('db-export',{
+                        filename: fn,
+                        error: e.message
+                    });
+                }
+                return;
+            }
+            case 'open': {
+                /* Expects: {
+                   buffer: ArrayBuffer | Uint8Array,
+                   filename: for logging/informational purposes only
+                   } */
+                const opt = ev.data;
+                let buffer = opt.buffer;
+                if(buffer instanceof Uint8Array){
+                }else if(buffer instanceof ArrayBuffer){
+                    buffer = new Uint8Array(buffer);
+                }else{
+                    stderr("'open' expects {buffer:Uint8Array} containing an uploaded db.");
+                    return;
+                }
+                const fn = (
+                    opt.filename
+                        ? opt.filename.split(/[/\\]/).pop().replace('"','_')
+                        : ("db-"+((Math.random() * 10000000) | 0)+
+                           "-"+((Math.random() * 10000000) | 0)+".sqlite3")
+                );
+                /* We cannot delete the existing db file until the new one
+                   is installed, which means that we risk overflowing our
+                   quota (if any) by having both the previous and current
+                   db briefly installed in the virtual filesystem. */
+                fiddleModule.FS.createDataFile("/", fn, buffer, true, true);
+                const oldName = Sqlite3Shell.dbFilename();
+                Sqlite3Shell.exec('.open "/'+fn+'"');
+                if(oldName && oldName !== fn){
+                    try{fiddleModule.FS.unlink(oldName);}
+                    catch(e){/*ignored*/}
+                }
+                stdout("Replaced DB with",fn+".");
+                return;
+            }
+        };
+        console.warn("Unknown fiddle-worker message type:",ev);
+    };
+   
+    /**
+       emscripten module for use with build mode -sMODULARIZE.
+    */
+    const fiddleModule = {
+        print: stdout,
+        printErr: stderr,
+        /**
+           Intercepts status updates from the emscripting module init
+           and fires worker events with a type of 'status' and a
+           payload of:
+
+           {
+           text: string | null, // null at end of load process
+           step: integer // starts at 1, increments 1 per call
+           }
+
+           We have no way of knowing in advance how many steps will
+           be processed/posted, so creating a "percentage done" view is
+           not really practical. One can be approximated by giving it a
+           current value of message.step and max value of message.step+1,
+           though.
+
+           When work is finished, a message with a text value of null is
+           submitted.
+
+           After a message with text==null is posted, the module may later
+           post messages about fatal problems, e.g. an exit() being
+           triggered, so it is recommended that UI elements for posting
+           status messages not be outright removed from the DOM when
+           text==null, and that they instead be hidden until/unless
+           text!=null.
+        */
+        setStatus: function f(text){
+            if(!f.last) f.last = { step: 0, text: '' };
+            else if(text === f.last.text) return;
+            f.last.text = text;
+            wMsg('module',{
+                type:'status',
+                data:{step: ++f.last.step, text: text||null}
+            });
+        }
+    };
+
+    importScripts('fiddle-module.js');
+    /**
+       initFiddleModule() is installed via fiddle-module.js due to
+       building with:
+
+       emcc ... -sMODULARIZE=1 -sEXPORT_NAME=initFiddleModule
+    */
+    initFiddleModule(fiddleModule).then(function(thisModule){
+        wMsg('fiddle-ready');
+    });
+})();
@@ -0,0 +1,283 @@
+<!doctype html>
+<html lang="en-us">
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+    <title>SQLite3 Fiddle</title>
+    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
+    <!-- to add a togglable terminal-style view, uncomment the following
+         two lines and ensure that these files are on the web server. -->
+    <!--script src="jqterm/jqterm-bundle.min.js"></script>
+    <link rel="stylesheet" href="jqterm/jquery.terminal.min.css"/-->
+    <link rel="stylesheet" href="emscripten.css"/>
+    <style>
+      /* The following styles are for app-level use. */
+      :root {
+          --sqlite-blue: #044a64;
+          --textarea-color1: #044a64;
+          --textarea-color2: white;
+      }
+      textarea {
+          font-family: monospace;
+          flex: 1 1 auto;
+          background-color: var(--textarea-color1);
+          color: var(--textarea-color2);
+      }
+      textarea#input {
+          color: var(--textarea-color1);
+          background-color: var(--textarea-color2);
+      }
+      header {
+          display: flex;
+          justify-content: space-between;
+          align-items: center;
+          background-color: var(--sqlite-blue);
+          color: white;
+          font-size: 120%;
+          font-weight: bold;
+          border-radius: 0.25em;
+          padding: 0.2em 0.5em;
+      }
+      header > .powered-by {
+          font-size: 80%;
+      }
+      header a, header a:visited, header a:hover {
+          color: inherit;
+      }
+      #main-wrapper {
+          display: flex;
+          flex-direction: column-reverse;
+          flex: 1 1 auto;
+          margin: 0.5em 0;
+          overflow: hidden;
+      }
+      #main-wrapper.side-by-side {
+          flex-direction: row;
+      }
+      #main-wrapper.side-by-side > fieldset {
+          margin-left: 0.25em;
+          margin-right: 0.25em;
+      }
+      #main-wrapper:not(.side-by-side) > fieldset {
+          margin-bottom: 0.25em;
+      }
+      #main-wrapper.swapio {
+          flex-direction: column;
+      }
+      #main-wrapper.side-by-side.swapio {
+          flex-direction: row-reverse;
+      }
+      .zone-wrapper{
+          display: flex;
+          margin: 0;
+          flex: 1 1 0%;
+          border-radius: 0.5em;
+          min-width: inherit/*important: resolves inability to scroll fieldset child element!*/;
+          padding: 0.35em 0 0 0;
+      }
+      .zone-wrapper textarea {
+          border-radius: 0.5em;
+          flex: 1 1 auto;
+          /*min/max width resolve an inexplicable margin on the RHS.  The -1em
+            is for the padding, else we overlap the parent boundaries.*/
+          /*min-width: calc(100% - 1em);
+          max-width: calc(100% - 1em);
+          padding: 0 0.5em;*/
+      }
+
+      .zone-wrapper.input { flex: 10 1 auto; }
+      .zone-wrapper.output { flex: 20 1 auto; }
+      .zone-wrapper > div {
+          display:flex;
+          flex: 1 1 0%;
+      }
+      .zone-wrapper.output {}
+      .button-bar {
+          display: flex;
+          flex-wrap: wrap;
+          align-items: center;
+          align-content: space-between;
+          justify-content: flex-start;
+      }
+      .button-bar > * {
+          margin: 0.05em 0.5em 0.05em 0;
+          flex: 0 1 auto;
+          align-self: auto;
+      }
+      label[for] {
+          cursor: pointer;
+      }
+      .error {
+          color: red;
+          background-color: yellow;
+      }
+      .hidden, .initially-hidden {
+          position: absolute !important;
+          opacity: 0 !important;
+          pointer-events: none !important;
+          display: none !important;
+      }
+      fieldset {
+          border-radius: 0.5em;
+          border: 1px inset;
+          padding: 0.25em;
+      }
+      fieldset.options {
+          font-size: 80%;
+          margin-top: 0.5em;
+      }
+      fieldset:not(.options) > legend {
+          font-size: 80%;
+      }
+      fieldset.options > div {
+          display: flex;
+          flex-wrap: wrap;
+      }
+      fieldset button {
+          font-size: inherit;
+      }
+      fieldset.collapsible > legend > .fieldset-toggle::after {
+          content: " [hide]";
+          position: relative;
+      }
+      fieldset.collapsible.collapsed > legend > .fieldset-toggle::after {
+          content: " [show]";
+          position: relative;
+      }
+      span.labeled-input {
+          padding: 0.25em;
+          margin: 0.05em 0.25em;
+          border-radius: 0.25em;
+          white-space: nowrap;
+          background: #0002;
+          display: flex;
+          align-items: center;
+      }
+      span.labeled-input > *:nth-child(2) {
+          margin-left: 0.3em;
+      }
+      .center { text-align: center; }
+      body.terminal-mode {
+          max-height: calc(100% - 2em);
+          display: flex;
+          flex-direction: column;
+          align-items: stretch;
+      }
+      #view-terminal {}
+      .app-view {
+          flex: 20 1 auto;
+      }
+      #view-split {
+          display: flex;
+          flex-direction: column-reverse;
+      }
+    </style>
+  </head>
+  <body>
+    <header id='titlebar'>
+      <span>SQLite3 Fiddle</span>
+      <span class='powered-by'>Powered by
+        <a href='https://sqlite.org'>SQLite3</a></span>
+    </header>
+    <!-- emscripten bits -->
+    <figure id="module-spinner">
+      <div class="spinner"></div>
+      <div class='center'><strong>Initializing app...</strong></div>
+      <div class='center'>
+        On a slow internet connection this may take a moment.  If this
+        message displays for "a long time", intialization may have
+        failed and the JavaScript console may contain clues as to why.
+      </div>
+    </figure>
+    <div class="emscripten" id="module-status">Downloading...</div>
+    <div class="emscripten">
+      <progress value="0" max="100" id="module-progress" hidden='1'></progress>  
+    </div><!-- /emscripten bits -->
+
+    <div id='view-terminal' class='app-view hidden initially-hidden'>
+      This is a placeholder for a terminal-like view which is not in
+      the default build.
+    </div>
+
+    <div id='view-split' class='app-view initially-hidden'>
+      <fieldset class='options collapsible'>
+        <legend><button class='fieldset-toggle'>Options</button></legend>
+        <div class=''>
+          <span class='labeled-input'>
+            <input type='checkbox' id='opt-cb-sbs'
+                   data-csstgt='#main-wrapper'
+                   data-cssclass='side-by-side'
+                   data-config='sideBySide'>
+            <label for='opt-cb-sbs'>Side-by-side</label>
+          </span>
+          <span class='labeled-input'>
+            <input type='checkbox' id='opt-cb-swapio'
+                   data-csstgt='#main-wrapper'
+                   data-cssclass='swapio'
+                   data-config='swapInOut'>
+            <label for='opt-cb-swapio'>Swap in/out</label>
+          </span>
+          <span class='labeled-input'>
+            <input type='checkbox' id='opt-cb-autoscroll'
+                   data-config='autoScrollOutput'>
+            <label for='opt-cb-autoscroll'>Auto-scroll output</label>
+          </span>
+          <span class='labeled-input'>
+            <input type='checkbox' id='opt-cb-autoclear'
+                   data-config='autoClearOutput'>
+            <label for='opt-cb-autoclear'>Auto-clear output</label>
+          </span>
+          <span class='labeled-input'>
+            <input type='file' id='load-db' class='hidden'/>
+            <button id='btn-load-db'>Load DB...</button>
+          </span>
+          <span class='labeled-input'>
+            <button id='btn-export'>Download DB</button>
+          </span>
+          <span class='labeled-input'>
+            <button id='btn-reset'>Reset DB</button>
+          </span>
+        </div>
+      </fieldset><!-- .options -->
+      <div id='main-wrapper' class=''>
+        <fieldset class='zone-wrapper input'>
+          <legend><div class='button-bar'>
+            <button id='btn-shell-exec'>Run</button>
+            <button id='btn-clear'>Clear Input</button>
+            <!--button data-cmd='.help'>Help</button-->
+            <select id='select-examples'></select>
+          </div></legend>
+          <div><textarea id="input"
+                         placeholder="Shell input. Ctrl-enter/shift-enter runs it.">
+-- ==================================================
+-- Use ctrl-enter or shift-enter to execute sqlite3
+-- shell commands and SQL.
+-- If a subset of the text is currently selected,
+-- only that part is executed.
+-- ==================================================
+.nullvalue NULL
+.headers on
+</textarea></div>
+        </fieldset>
+        <fieldset class='zone-wrapper output'>
+          <legend><div class='button-bar'>
+            <button id='btn-clear-output'>Clear Output</button>
+            <button id='btn-interrupt' class='hidden' disabled>Interrupt</button>
+            <!-- interruption cannot work in the current configuration
+                 because we cannot send an interrupt message when work
+                 is currently underway. At that point the Worker is
+                 tied up and will not receive the message. -->
+          </div></legend>
+          <div><textarea id="output" readonly
+                         placeholder="Shell output."></textarea></div>
+        </fieldset>
+      </div>
+    </div> <!-- #view-split -->
+    <!-- Maintenance notes:
+
+        ... TODO... currently being refactored...
+
+    -->
+    <script src="fiddle.js"></script>
+  </body>
+</html>
@@ -0,0 +1,809 @@
+/*
+  2022-05-20
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  This is the main entry point for the sqlite3 fiddle app. It sets up the
+  various UI bits, loads a Worker for the db connection, and manages the
+  communication between the UI and worker.
+*/
+(function(){
+    'use strict';
+    /* Recall that the 'self' symbol, except where locally
+       overwritten, refers to the global window or worker object. */
+
+    const storage = (function(NS/*namespace object in which to store this module*/){
+        /* Pedantic licensing note: this code originated in the Fossil SCM
+           source tree, where it has a different license, but the person who
+           ported it into sqlite is the same one who wrote it for fossil. */
+        'use strict';
+        NS = NS||{};
+
+        /**
+           This module provides a basic wrapper around localStorage
+           or sessionStorage or a dummy proxy object if neither
+           of those are available.
+        */
+        const tryStorage = function f(obj){
+            if(!f.key) f.key = 'storage.access.check';
+            try{
+                obj.setItem(f.key, 'f');
+                const x = obj.getItem(f.key);
+                obj.removeItem(f.key);
+                if(x!=='f') throw new Error(f.key+" failed")
+                return obj;
+            }catch(e){
+                return undefined;
+            }
+        };
+
+        /** Internal storage impl for this module. */
+        const $storage =
+              tryStorage(window.localStorage)
+              || tryStorage(window.sessionStorage)
+              || tryStorage({
+                  // A basic dummy xyzStorage stand-in
+                  $$$:{},
+                  setItem: function(k,v){this.$$$[k]=v},
+                  getItem: function(k){
+                      return this.$$$.hasOwnProperty(k) ? this.$$$[k] : undefined;
+                  },
+                  removeItem: function(k){delete this.$$$[k]},
+                  clear: function(){this.$$$={}}
+              });
+
+        /**
+           For the dummy storage we need to differentiate between
+           $storage and its real property storage for hasOwnProperty()
+           to work properly...
+        */
+        const $storageHolder = $storage.hasOwnProperty('$$$') ? $storage.$$$ : $storage;
+
+        /**
+           A prefix which gets internally applied to all storage module
+           property keys so that localStorage and sessionStorage across the
+           same browser profile instance do not "leak" across multiple apps
+           being hosted by the same origin server. Such cross-polination is
+           still there but, with this key prefix applied, it won't be
+           immediately visible via the storage API.
+
+           With this in place we can justify using localStorage instead of
+           sessionStorage.
+
+           One implication of using localStorage and sessionStorage is that
+           their scope (the same "origin" and client application/profile)
+           allows multiple apps on the same origin to use the same
+           storage. Thus /appA/foo could then see changes made via
+           /appB/foo. The data do not cross user- or browser boundaries,
+           though, so it "might" arguably be called a
+           feature. storageKeyPrefix was added so that we can sandbox that
+           state for each separate app which shares an origin.
+
+           See: https://fossil-scm.org/forum/forumpost/4afc4d34de
+
+           Sidebar: it might seem odd to provide a key prefix and stick all
+           properties in the topmost level of the storage object. We do that
+           because adding a layer of object to sandbox each app would mean
+           (de)serializing that whole tree on every storage property change.
+           e.g. instead of storageObject.projectName.foo we have
+           storageObject[storageKeyPrefix+'foo']. That's soley for
+           efficiency's sake (in terms of battery life and
+           environment-internal storage-level effort).
+        */
+        const storageKeyPrefix = (
+            $storageHolder===$storage/*localStorage or sessionStorage*/
+                ? (
+                    (NS.config ?
+                     (NS.config.projectCode || NS.config.projectName
+                      || NS.config.shortProjectName)
+                     : false)
+                        || window.location.pathname
+                )+'::' : (
+                    '' /* transient storage */
+                )
+        );
+
+        /**
+           A proxy for localStorage or sessionStorage or a
+           page-instance-local proxy, if neither one is availble.
+
+           Which exact storage implementation is uses is unspecified, and
+           apps must not rely on it.
+        */
+        NS.storage = {
+            storageKeyPrefix: storageKeyPrefix,
+            /** Sets the storage key k to value v, implicitly converting
+                it to a string. */
+            set: (k,v)=>$storage.setItem(storageKeyPrefix+k,v),
+            /** Sets storage key k to JSON.stringify(v). */
+            setJSON: (k,v)=>$storage.setItem(storageKeyPrefix+k,JSON.stringify(v)),
+            /** Returns the value for the given storage key, or
+                dflt if the key is not found in the storage. */
+            get: (k,dflt)=>$storageHolder.hasOwnProperty(
+                storageKeyPrefix+k
+            ) ? $storage.getItem(storageKeyPrefix+k) : dflt,
+            /** Returns true if the given key has a value of "true".  If the
+                key is not found, it returns true if the boolean value of dflt
+                is "true". (Remember that JS persistent storage values are all
+                strings.) */
+            getBool: function(k,dflt){
+                return 'true'===this.get(k,''+(!!dflt));
+            },
+            /** Returns the JSON.parse()'d value of the given
+                storage key's value, or dflt is the key is not
+                found or JSON.parse() fails. */
+            getJSON: function f(k,dflt){
+                try {
+                    const x = this.get(k,f);
+                    return x===f ? dflt : JSON.parse(x);
+                }
+                catch(e){return dflt}
+            },
+            /** Returns true if the storage contains the given key,
+                else false. */
+            contains: (k)=>$storageHolder.hasOwnProperty(storageKeyPrefix+k),
+            /** Removes the given key from the storage. Returns this. */
+            remove: function(k){
+                $storage.removeItem(storageKeyPrefix+k);
+                return this;
+            },
+            /** Clears ALL keys from the storage. Returns this. */
+            clear: function(){
+                this.keys().forEach((k)=>$storage.removeItem(/*w/o prefix*/k));
+                return this;
+            },
+            /** Returns an array of all keys currently in the storage. */
+            keys: ()=>Object.keys($storageHolder).filter((v)=>(v||'').startsWith(storageKeyPrefix)),
+            /** Returns true if this storage is transient (only available
+                until the page is reloaded), indicating that fileStorage
+                and sessionStorage are unavailable. */
+            isTransient: ()=>$storageHolder!==$storage,
+            /** Returns a symbolic name for the current storage mechanism. */
+            storageImplName: function(){
+                if($storage===window.localStorage) return 'localStorage';
+                else if($storage===window.sessionStorage) return 'sessionStorage';
+                else return 'transient';
+            },
+
+            /**
+               Returns a brief help text string for the currently-selected
+               storage type.
+            */
+            storageHelpDescription: function(){
+                return {
+                    localStorage: "Browser-local persistent storage with an "+
+                        "unspecified long-term lifetime (survives closing the browser, "+
+                        "but maybe not a browser upgrade).",
+                    sessionStorage: "Storage local to this browser tab, "+
+                        "lost if this tab is closed.",
+                    "transient": "Transient storage local to this invocation of this page."
+                }[this.storageImplName()];
+            }
+        };
+        return NS.storage;
+    })({})/*storage API setup*/;
+
+
+    /** Name of the stored copy of SqliteFiddle.config. */
+    const configStorageKey = 'sqlite3-fiddle-config';
+
+    /**
+       The SqliteFiddle object is intended to be the primary
+       app-level object for the main-thread side of the sqlite
+       fiddle application. It uses a worker thread to load the
+       sqlite WASM module and communicate with it.
+    */
+    const SF/*local convenience alias*/
+    = window.SqliteFiddle/*canonical name*/ = {
+        /* Config options. */
+        config: {
+            /* If true, SqliteFiddle.echo() will auto-scroll the
+               output widget to the bottom when it receives output,
+               else it won't. */
+            autoScrollOutput: true,
+            /* If true, the output area will be cleared before each
+               command is run, else it will not. */
+            autoClearOutput: false,
+            /* If true, SqliteFiddle.echo() will echo its output to
+               the console, in addition to its normal output widget.
+               That slows it down but is useful for testing. */
+            echoToConsole: false,
+            /* If true, display input/output areas side-by-side. */
+            sideBySide: true,
+            /* If true, swap positions of the input/output areas. */
+            swapInOut: false
+        },
+        /**
+           Emits the given text, followed by a line break, to the
+           output widget.  If given more than one argument, they are
+           join()'d together with a space between each. As a special
+           case, if passed a single array, that array is used in place
+           of the arguments array (this is to facilitate receiving
+           lists of arguments via worker events).
+        */
+        echo: function f(text) {
+            /* Maintenance reminder: we currently require/expect a textarea
+               output element. It might be nice to extend this to behave
+               differently if the output element is a non-textarea element,
+               in which case it would need to append the given text as a TEXT
+               node and add a line break. */
+            if(!f._){
+                f._ = document.getElementById('output');
+                f._.value = ''; // clear browser cache
+            }
+            if(arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
+            else if(1===arguments.length && Array.isArray(text)) text = text.join(' ');
+            // These replacements are necessary if you render to raw HTML
+            //text = text.replace(/&/g, "&amp;");
+            //text = text.replace(/</g, "&lt;");
+            //text = text.replace(/>/g, "&gt;");
+            //text = text.replace('\n', '<br>', 'g');
+            if(null===text){/*special case: clear output*/
+                f._.value = '';
+                return;
+            }else if(this.echo._clearPending){
+                delete this.echo._clearPending;
+                f._.value = '';
+            }
+            if(this.config.echoToConsole) console.log(text);
+            if(this.jqTerm) this.jqTerm.echo(text);
+            f._.value += text + "\n";
+            if(this.config.autoScrollOutput){
+                f._.scrollTop = f._.scrollHeight;
+            }
+        },
+        _msgMap: {},
+        /** Adds a worker message handler for messages of the given
+            type. */
+        addMsgHandler: function f(type,callback){
+            if(Array.isArray(type)){
+                type.forEach((t)=>this.addMsgHandler(t, callback));
+                return this;
+            }
+            (this._msgMap.hasOwnProperty(type)
+             ? this._msgMap[type]
+             : (this._msgMap[type] = [])).push(callback);
+            return this;
+        },
+        /** Given a worker message, runs all handlers for msg.type. */
+        runMsgHandlers: function(msg){
+            const list = (this._msgMap.hasOwnProperty(msg.type)
+                          ? this._msgMap[msg.type] : false);
+            if(!list){
+                console.warn("No handlers found for message type:",msg);
+                return false;
+            }
+            //console.debug("runMsgHandlers",msg);
+            list.forEach((f)=>f(msg));
+            return true;
+        },
+        /** Removes all message handlers for the given message type. */
+        clearMsgHandlers: function(type){
+            delete this._msgMap[type];
+            return this;
+        },
+        /* Posts a message in the form {type, data} to the db worker. Returns this. */
+        wMsg: function(type,data){
+            this.worker.postMessage({type, data});
+            return this;
+        },
+        /**
+           Prompts for confirmation and, if accepted, deletes
+           all content and tables in the (transient) database.
+        */
+        resetDb: function(){
+            if(window.confirm("Really destroy all content and tables "
+                              +"in the (transient) db?")){
+                this.wMsg('db-reset');
+            }
+            return this;
+        },
+        /** Stores this object's config in the browser's storage. */
+        storeConfig: function(){
+            storage.setJSON(configStorageKey,this.config);
+        }
+    };
+
+    if(1){ /* Restore SF.config */
+        const storedConfig = storage.getJSON(configStorageKey);
+        if(storedConfig){
+            /* Copy all properties to SF.config which are currently in
+               storedConfig. We don't bother copying any other
+               properties: those have been removed from the app in the
+               meantime. */
+            Object.keys(SF.config).forEach(function(k){
+                if(storedConfig.hasOwnProperty(k)){
+                    SF.config[k] = storedConfig[k];
+                }
+            });
+        }
+    }
+
+    SF.worker = new Worker('fiddle-worker.js');
+    SF.worker.onmessage = (ev)=>SF.runMsgHandlers(ev.data);
+    SF.addMsgHandler(['stdout', 'stderr'], (ev)=>SF.echo(ev.data));
+
+    /* querySelectorAll() proxy */
+    const EAll = function(/*[element=document,] cssSelector*/){
+        return (arguments.length>1 ? arguments[0] : document)
+            .querySelectorAll(arguments[arguments.length-1]);
+    };
+    /* querySelector() proxy */
+    const E = function(/*[element=document,] cssSelector*/){
+        return (arguments.length>1 ? arguments[0] : document)
+            .querySelector(arguments[arguments.length-1]);
+    };
+
+    /** Handles status updates from the Module object. */
+    SF.addMsgHandler('module', function f(ev){
+        ev = ev.data;
+        if('status'!==ev.type){
+            console.warn("Unexpected module-type message:",ev);
+            return;
+        }
+        if(!f.ui){
+            f.ui = {
+                status: E('#module-status'),
+                progress: E('#module-progress'),
+                spinner: E('#module-spinner')
+            };
+        }
+        const msg = ev.data;
+        if(f.ui.progres){
+            progress.value = msg.step;
+            progress.max = msg.step + 1/*we don't know how many steps to expect*/;
+        }
+        if(1==msg.step){
+            f.ui.progress.classList.remove('hidden');
+            f.ui.spinner.classList.remove('hidden');
+        }
+        if(msg.text){
+            f.ui.status.classList.remove('hidden');
+            f.ui.status.innerText = msg.text;
+        }else{
+            if(f.ui.progress){
+                f.ui.progress.remove();
+                f.ui.spinner.remove();
+                delete f.ui.progress;
+                delete f.ui.spinner;
+            }
+            f.ui.status.classList.add('hidden');
+            /* The module can post messages about fatal problems,
+               e.g. an exit() being triggered or assertion failure,
+               after the last "load" message has arrived, so
+               leave f.ui.status and message listener intact. */
+        }
+    });
+
+    /**
+       The 'fiddle-ready' event is fired (with no payload) when the
+       wasm module has finished loading. Interestingly, that happens
+       _before_ the final module:status event */
+    SF.addMsgHandler('fiddle-ready', function(){
+        SF.clearMsgHandlers('fiddle-ready');
+        self.onSFLoaded();
+    });
+
+    /**
+       Performs all app initialization which must wait until after the
+       worker module is loaded. This function removes itself when it's
+       called.
+    */
+    self.onSFLoaded = function(){
+        delete this.onSFLoaded;
+        // Unhide all elements which start out hidden
+        EAll('.initially-hidden').forEach((e)=>e.classList.remove('initially-hidden'));
+        E('#btn-reset').addEventListener('click',()=>SF.resetDb());
+        const taInput = E('#input');
+        const btnClearIn = E('#btn-clear');
+        btnClearIn.addEventListener('click',function(){
+            taInput.value = '';
+        },false);
+        // Ctrl-enter and shift-enter both run the current SQL.
+        taInput.addEventListener('keydown',function(ev){
+            if((ev.ctrlKey || ev.shiftKey) && 13 === ev.keyCode){
+                ev.preventDefault();
+                ev.stopPropagation();
+                btnShellExec.click();
+            }
+        }, false);
+        const taOutput = E('#output');
+        const btnClearOut = E('#btn-clear-output');
+        btnClearOut.addEventListener('click',function(){
+            taOutput.value = '';
+            if(SF.jqTerm) SF.jqTerm.clear();
+        },false);
+        const btnShellExec = E('#btn-shell-exec');
+        btnShellExec.addEventListener('click',function(ev){
+            let sql;
+            ev.preventDefault();
+            if(taInput.selectionStart<taInput.selectionEnd){
+                sql = taInput.value.substring(taInput.selectionStart,taInput.selectionEnd).trim();
+            }else{
+                sql = taInput.value.trim();
+            }
+            if(sql) SF.dbExec(sql);
+        },false);
+
+        const btnInterrupt = E("#btn-interrupt");
+        //btnInterrupt.classList.add('hidden');
+        /** To be called immediately before work is sent to the
+            worker. Updates some UI elements. The 'working'/'end'
+            event will apply the inverse, undoing the bits this
+            function does. This impl is not in the 'working'/'start'
+            event handler because that event is given to us
+            asynchronously _after_ we need to have performed this
+            work.
+        */
+        const preStartWork = function f(){
+            if(!f._){
+                const title = E('title');
+                f._ = {
+                    btnLabel: btnShellExec.innerText,
+                    pageTitle: title,
+                    pageTitleOrig: title.innerText
+                };
+            }
+            f._.pageTitle.innerText = "[working...] "+f._.pageTitleOrig;
+            btnShellExec.setAttribute('disabled','disabled');
+            btnInterrupt.removeAttribute('disabled','disabled');
+        };
+
+        /* Sends the given text to the db module to evaluate as if it
+           had been entered in the sqlite3 CLI shell. If it's null or
+           empty, this is a no-op except that the very first call will
+           initialize the db and output an informational header. */
+        SF.dbExec = function f(sql){
+            if(this.config.autoClearOutput){
+                this.echo._clearPending = true;
+            }
+            preStartWork();
+            this.wMsg('shellExec',sql);
+        };
+
+        SF.addMsgHandler('working',function f(ev){
+            switch(ev.data){
+                case 'start': /* See notes in preStartWork(). */; return;
+                case 'end':
+                    preStartWork._.pageTitle.innerText = preStartWork._.pageTitleOrig;
+                    btnShellExec.innerText = preStartWork._.btnLabel;
+                    btnShellExec.removeAttribute('disabled');
+                    btnInterrupt.setAttribute('disabled','disabled');
+                    return;
+            }
+            console.warn("Unhandled 'working' event:",ev.data);
+        });
+
+        /* For each checkbox with data-csstgt, set up a handler which
+           toggles the given CSS class on the element matching
+           E(data-csstgt). */
+        EAll('input[type=checkbox][data-csstgt]')
+            .forEach(function(e){
+                const tgt = E(e.dataset.csstgt);
+                const cssClass = e.dataset.cssclass || 'error';
+                e.checked = tgt.classList.contains(cssClass);
+                e.addEventListener('change', function(){
+                    tgt.classList[
+                        this.checked ? 'add' : 'remove'
+                    ](cssClass)
+                }, false);
+            });
+        /* For each checkbox with data-config=X, set up a binding to
+           SF.config[X]. These must be set up AFTER data-csstgt
+           checkboxes so that those two states can be synced properly. */
+        EAll('input[type=checkbox][data-config]')
+            .forEach(function(e){
+                const confVal = !!SF.config[e.dataset.config];
+                if(e.checked !== confVal){
+                    /* Ensure that data-csstgt mappings (if any) get
+                       synced properly. */
+                    e.checked = confVal;
+                    e.dispatchEvent(new Event('change'));
+                }
+                e.addEventListener('change', function(){
+                    SF.config[this.dataset.config] = this.checked;
+                    SF.storeConfig();
+                }, false);
+            });
+        /* For each button with data-cmd=X, map a click handler which
+           calls SF.dbExec(X). */
+        const cmdClick = function(){SF.dbExec(this.dataset.cmd);};
+        EAll('button[data-cmd]').forEach(
+            e => e.addEventListener('click', cmdClick, false)
+        );
+
+        btnInterrupt.addEventListener('click',function(){
+            SF.wMsg('interrupt');
+        });
+
+        /** Initiate a download of the db. */
+        const btnExport = E('#btn-export');
+        const eLoadDb = E('#load-db');
+        const btnLoadDb = E('#btn-load-db');
+        btnLoadDb.addEventListener('click', ()=>eLoadDb.click());
+        /**
+           Enables (if passed true) or disables all UI elements which
+           "might," if timed "just right," interfere with an
+           in-progress db import/export/exec operation.
+        */
+        const enableMutatingElements = function f(enable){
+            if(!f._elems){
+                f._elems = [
+                    /* UI elements to disable while import/export are
+                       running. Normally the export is fast enough
+                       that this won't matter, but we really don't
+                       want to be reading (from outside of sqlite) the
+                       db when the user taps btnShellExec. */
+                    btnShellExec, btnExport, eLoadDb
+                ];
+            }
+            f._elems.forEach( enable
+                              ? (e)=>e.removeAttribute('disabled')
+                              : (e)=>e.setAttribute('disabled','disabled') );
+        };
+        btnExport.addEventListener('click',function(){
+            enableMutatingElements(false);
+            SF.wMsg('db-export');
+        });
+        SF.addMsgHandler('db-export', function(ev){
+            enableMutatingElements(true);
+            ev = ev.data;
+            if(ev.error){
+                SF.echo("Export failed:",ev.error);
+                return;
+            }
+            const blob = new Blob([ev.buffer], {type:"application/x-sqlite3"});
+            const a = document.createElement('a');
+            document.body.appendChild(a);
+            a.href = window.URL.createObjectURL(blob);
+            a.download = ev.filename;
+            a.addEventListener('click',function(){
+                setTimeout(function(){
+                    SF.echo("Exported (possibly auto-downloaded):",ev.filename);
+                    window.URL.revokeObjectURL(a.href);
+                    a.remove();
+                },500);
+            });
+            a.click();
+        });
+        /**
+           Handle load/import of an external db file.
+        */
+        eLoadDb.addEventListener('change',function(){
+            const f = this.files[0];
+            const r = new FileReader();
+            const status = {loaded: 0, total: 0};
+            enableMutatingElements(false);
+            r.addEventListener('loadstart', function(){
+                SF.echo("Loading",f.name,"...");
+            });
+            r.addEventListener('progress', function(ev){
+                SF.echo("Loading progress:",ev.loaded,"of",ev.total,"bytes.");
+            });
+            const that = this;
+            r.addEventListener('load', function(){
+                enableMutatingElements(true);
+                SF.echo("Loaded",f.name+". Opening db...");
+                SF.wMsg('open',{
+                    filename: f.name,
+                    buffer: this.result
+                });
+            });
+            r.addEventListener('error',function(){
+                enableMutatingElements(true);
+                SF.echo("Loading",f.name,"failed for unknown reasons.");
+            });
+            r.addEventListener('abort',function(){
+                enableMutatingElements(true);
+                SF.echo("Cancelled loading of",f.name+".");
+            });
+            r.readAsArrayBuffer(f);
+        });
+
+        EAll('fieldset.collapsible').forEach(function(fs){
+            const btnToggle = E(fs,'legend > .fieldset-toggle'),
+                  content = EAll(fs,':scope > div');
+            btnToggle.addEventListener('click', function(){
+                fs.classList.toggle('collapsed');
+                content.forEach((d)=>d.classList.toggle('hidden'));
+            }, false);
+        });
+
+        /**
+           Given a DOM element, this routine measures its "effective
+           height", which is the bounding top/bottom range of this element
+           and all of its children, recursively. For some DOM structure
+           cases, a parent may have a reported height of 0 even though
+           children have non-0 sizes.
+
+           Returns 0 if !e or if the element really has no height.
+        */
+        const effectiveHeight = function f(e){
+            if(!e) return 0;
+            if(!f.measure){
+                f.measure = function callee(e, depth){
+                    if(!e) return;
+                    const m = e.getBoundingClientRect();
+                    if(0===depth){
+                        callee.top = m.top;
+                        callee.bottom = m.bottom;
+                    }else{
+                        callee.top = m.top ? Math.min(callee.top, m.top) : callee.top;
+                        callee.bottom = Math.max(callee.bottom, m.bottom);
+                    }
+                    Array.prototype.forEach.call(e.children,(e)=>callee(e,depth+1));
+                    if(0===depth){
+                        //console.debug("measure() height:",e.className, callee.top, callee.bottom, (callee.bottom - callee.top));
+                        f.extra += callee.bottom - callee.top;
+                    }
+                    return f.extra;
+                };
+            }
+            f.extra = 0;
+            f.measure(e,0);
+            return f.extra;
+        };
+
+        /**
+           Returns a function, that, as long as it continues to be invoked,
+           will not be triggered. The function will be called after it stops
+           being called for N milliseconds. If `immediate` is passed, call
+           the callback immediately and hinder future invocations until at
+           least the given time has passed.
+
+           If passed only 1 argument, or passed a falsy 2nd argument,
+           the default wait time set in this function's $defaultDelay
+           property is used.
+
+           Source: underscore.js, by way of https://davidwalsh.name/javascript-debounce-function
+        */
+        const debounce = function f(func, wait, immediate) {
+            var timeout;
+            if(!wait) wait = f.$defaultDelay;
+            return function() {
+                const context = this, args = Array.prototype.slice.call(arguments);
+                const later = function() {
+                    timeout = undefined;
+                    if(!immediate) func.apply(context, args);
+                };
+                const callNow = immediate && !timeout;
+                clearTimeout(timeout);
+                timeout = setTimeout(later, wait);
+                if(callNow) func.apply(context, args);
+            };
+        };
+        debounce.$defaultDelay = 500 /*arbitrary*/;
+
+        const ForceResizeKludge = (function(){
+            /* Workaround for Safari mayhem regarding use of vh CSS
+               units....  We cannot use vh units to set the main view
+               size because Safari chokes on that, so we calculate
+               that height here. Larger than ~95% is too big for
+               Firefox on Android, causing the input area to move
+               off-screen. */
+            const appViews = EAll('.app-view');
+            const elemsToCount = [
+                /* Elements which we need to always count in the
+                   visible body size. */
+                E('body > header'),
+                E('body > footer')
+            ];
+            const resized = function f(){
+                if(f.$disabled) return;
+                const wh = window.innerHeight;
+                var ht;
+                var extra = 0;
+                elemsToCount.forEach((e)=>e ? extra += effectiveHeight(e) : false);
+                ht = wh - extra;
+                appViews.forEach(function(e){
+                    e.style.height =
+                        e.style.maxHeight = [
+                            "calc(", (ht>=100 ? ht : 100), "px",
+                            " - 2em"/*fudge value*/,")"
+                            /* ^^^^ hypothetically not needed, but both
+                               Chrome/FF on Linux will force scrollbars on the
+                               body if this value is too small. */
+                        ].join('');
+                });
+            };
+            resized.$disabled = true/*gets deleted when setup is finished*/;
+            window.addEventListener('resize', debounce(resized, 250), false);
+            return resized;
+        })();
+
+        /** Set up a selection list of examples */
+        (function(){
+            const xElem = E('#select-examples');
+            const examples = [
+                {name: "Help", sql:
+`-- ================================================
+-- Use ctrl-enter or shift-enter to execute sqlite3
+-- shell commands and SQL.
+-- If a subset of the text is currently selected,
+-- only that part is executed.
+-- ================================================
+.help`},
+                {name: "Timer on", sql: ".timer on"},
+                {name: "Setup table T", sql:`.nullvalue NULL
+CREATE TABLE t(a,b);
+INSERT INTO t(a,b) VALUES('abc',123),('def',456),(NULL,789),('ghi',012);
+SELECT * FROM t;`},
+                {name: "Table list", sql: ".tables"},
+                {name: "Box Mode", sql: ".mode box"},
+                {name: "JSON Mode", sql: ".mode json"},
+                {name: "Mandlebrot", sql: `WITH RECURSIVE
+  xaxis(x) AS (VALUES(-2.0) UNION ALL SELECT x+0.05 FROM xaxis WHERE x<1.2),
+  yaxis(y) AS (VALUES(-1.0) UNION ALL SELECT y+0.1 FROM yaxis WHERE y<1.0),
+  m(iter, cx, cy, x, y) AS (
+    SELECT 0, x, y, 0.0, 0.0 FROM xaxis, yaxis
+    UNION ALL
+    SELECT iter+1, cx, cy, x*x-y*y + cx, 2.0*x*y + cy FROM m 
+     WHERE (x*x + y*y) < 4.0 AND iter<28
+  ),
+  m2(iter, cx, cy) AS (
+    SELECT max(iter), cx, cy FROM m GROUP BY cx, cy
+  ),
+  a(t) AS (
+    SELECT group_concat( substr(' .+*#', 1+min(iter/7,4), 1), '') 
+    FROM m2 GROUP BY cy
+  )
+SELECT group_concat(rtrim(t),x'0a') as Mandelbrot FROM a;`}
+            ];
+            const newOpt = function(lbl,val){
+                const o = document.createElement('option');
+                o.value = val;
+                if(!val) o.setAttribute('disabled',true);
+                o.appendChild(document.createTextNode(lbl));
+                xElem.appendChild(o);
+            };
+            newOpt("Examples (replaces input!)");
+            examples.forEach((o)=>newOpt(o.name, o.sql));
+            //xElem.setAttribute('disabled',true);
+            xElem.selectedIndex = 0;
+            xElem.addEventListener('change', function(){
+                taInput.value = '-- ' +
+                    this.selectedOptions[0].innerText +
+                    '\n' + this.value;
+                SF.dbExec(this.value);
+            });
+        })()/* example queries */;
+
+        SF.echo(null/*clear any output generated by the init process*/);
+        if(window.jQuery && window.jQuery.terminal){
+            /* Set up the terminal-style view... */
+            const eTerm = window.jQuery('#view-terminal').empty();
+            SF.jqTerm = eTerm.terminal(SF.dbExec.bind(SF),{
+                prompt: 'sqlite> ',
+                greetings: false /* note that the docs incorrectly call this 'greeting' */
+            });
+            /* Set up a button to toggle the views... */
+            const head = E('header#titlebar');
+            const btnToggleView = document.createElement('button');
+            btnToggleView.appendChild(document.createTextNode("Toggle View"));
+            head.appendChild(btnToggleView);
+            btnToggleView.addEventListener('click',function f(){
+                EAll('.app-view').forEach(e=>e.classList.toggle('hidden'));
+                if(document.body.classList.toggle('terminal-mode')){
+                    ForceResizeKludge();
+                }
+            }, false);
+            btnToggleView.click()/*default to terminal view*/;
+        }
+        SF.dbExec(null/*init the db and output the header*/);
+        SF.echo('This experimental app is provided in the hope that it',
+                'may prove interesting or useful but is not an officially',
+                'supported deliverable of the sqlite project. It is subject to',
+                'any number of changes or outright removal at any time.\n');
+        delete ForceResizeKludge.$disabled;
+        ForceResizeKludge();
+
+        btnShellExec.click();
+    }/*onSFLoaded()*/;
+})();
@@ -0,0 +1,94 @@
+This directory houses a "fiddle"-style application which embeds a
+[Web Assembly (WASM)](https://en.wikipedia.org/wiki/WebAssembly)
+build of the sqlite3 shell app into an HTML page, effectively running
+the shell in a client-side browser.
+
+It requires [emscripten][] and that the build environment be set up for
+emscripten. A mini-HOWTO for setting that up follows...
+
+First, install the Emscripten SDK, as documented
+[here](https://emscripten.org/docs/getting_started/downloads.html) and summarized
+below for Linux environments:
+
+```
+# Clone the emscripten repository:
+$ git clone https://github.com/emscripten-core/emsdk.git
+$ cd emsdk
+
+# Download and install the latest SDK tools:
+$ ./emsdk install latest
+
+# Make the "latest" SDK "active" for the current user:
+$ ./emsdk activate latest
+```
+
+Those parts only need to be run once. The following needs to be run for each
+shell instance which needs the `emcc` compiler:
+
+```
+# Activate PATH and other environment variables in the current terminal:
+$ source ./emsdk_env.sh
+
+$ which emcc
+/path/to/emsdk/upstream/emscripten/emcc
+```
+
+That `env` script needs to be sourced for building this application from the
+top of the sqlite3 build tree:
+
+```
+$ make fiddle
+```
+
+Or:
+
+```
+$ cd ext/fiddle
+$ make
+```
+
+That will generate the fiddle application under
+[ext/fiddle](/dir/ext/fiddle), as `fiddle.html`. That application
+cannot, due to XMLHttpRequest security limitations, run if the HTML
+file is opened directly in the browser (i.e. if it is opened using a
+`file://` URL), so it needs to be served via an HTTP server.  For
+example, using [althttpd][]:
+
+```
+$ cd ext/fiddle
+$ althttpd -debug 1 -jail 0 -port 9090 -root .
+```
+
+Then browse to `http://localhost:9090/fiddle.html`.
+
+Note that when serving this app via [althttpd][], it must be a version
+from 2022-05-17 or newer so that it recognizes the `.wasm` file
+extension and responds with the mimetype `application/wasm`, as the
+WASM loader is pedantic about that detail.
+
+# Known Quirks and Limitations
+
+Some "impedence mismatch" between C and WASM/JavaScript is to be
+expected.
+
+## No I/O
+
+sqlite3 shell commands which require file I/O or pipes are disabled in
+the WASM build.
+
+## `exit()` Triggered from C
+
+When C code calls `exit()`, as happens (for example) when running an
+"unsafe" command when safe mode is active, WASM's connection to the
+sqlite3 shell environment has no sensible choice but to shut down
+because `exit()` leaves it in a state we can no longer recover
+from. The JavaScript-side application attempts to recognize this and
+warn the user that restarting the application is necessary. Currently
+the only way to restart it is to reload the page. Restructuring the
+shell code such that it could be "rebooted" without restarting the
+JS app would require some invasive changes which are not currently
+on any TODO list but have not been entirely ruled out long-term.
+
+
+[emscripten]: https://emscripten.org
+[althttpd]: https://sqlite.org/althttpd
@@ -0,0 +1,44 @@
+/*
+  2022-05-23
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  This is a JS Worker file for the main sqlite3 api. It loads
+  sqlite3.js, initializes the module, and postMessage()'s a message
+  after the module is initialized:
+
+  {type: 'sqlite3-api', data: 'ready'}
+
+  This seemingly superfluous level of indirection is necessary when
+  loading sqlite3.js via a Worker. Loading sqlite3.js from the main
+  window thread elides the Worker-specific API. Instantiating a worker
+  with new Worker("sqlite.js") will not (cannot) call
+  initSqlite3Module() to initialize the module due to a
+  timing/order-of-operations conflict (and that symbol is not exported
+  in a way that a Worker loading it that way can see it).  Thus JS
+  code wanting to load the sqlite3 Worker-specific API needs to pass
+  _this_ file (or equivalent) to the Worker constructor and then
+  listen for an event in the form shown above in order to know when
+  the module has completed initialization. sqlite3.js will fire a
+  similar event, with data:'loaded' as the final step in its loading
+  process. Whether or not we _really_ need both 'loaded' and 'ready'
+  events is unclear, but they are currently separate events primarily
+  for the sake of clarity in the timing of when it's okay to use the
+  loaded module. At the time the 'loaded' event is fired, it's
+  possible (but unknown and unknowable) that the emscripten-generated
+  module-setup infrastructure still has work to do. Thus it is
+  hypothesized that client code is better off waiting for the 'ready'
+  even before using the API.
+*/
+"use strict";
+importScripts('sqlite3.js');
+initSqlite3Module().then(function(){
+    setTimeout(()=>self.postMessage({type:'sqlite3-api',data:'ready'}), 0);
+});
@@ -0,0 +1,31 @@
+textarea {
+    font-family: monospace;
+}
+header {
+    font-size: 130%;
+    font-weight: bold;
+}
+.hidden, .initially-hidden {
+    position: absolute !important;
+    opacity: 0 !important;
+    pointer-events: none !important;
+    display: none !important;
+}
+fieldset.options {
+    font-size: 75%;
+}
+fieldset > legend {
+    padding: 0 0.5em;
+}
+span.labeled-input {
+    padding: 0.25em;
+    margin: 0.25em 0.5em;
+    border-radius: 0.25em;
+    white-space: nowrap;
+    background: #0002;
+}
+.center { text-align: center; }
+.error {
+    color: red;
+    background-color: yellow;
+}
@@ -0,0 +1,33 @@
+<!doctype html>
+<html lang="en-us">
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
+    <link rel="stylesheet" href="emscripten.css"/>
+    <link rel="stylesheet" href="testing.css"/>
+    <title>sqlite3-api.js tests</title>
+    <style></style>
+  </head>
+  <body>
+    <header id='titlebar'><span>sqlite3-api.js tests</span></header>
+    <!-- emscripten bits -->
+    <figure id="module-spinner">
+      <div class="spinner"></div>
+      <div class='center'><strong>Initializing app...</strong></div>
+      <div class='center'>
+        On a slow internet connection this may take a moment.  If this
+        message displays for "a long time", intialization may have
+        failed and the JavaScript console may contain clues as to why.
+      </div>
+    </figure>
+    <div class="emscripten" id="module-status">Downloading...</div>
+    <div class="emscripten">
+      <progress value="0" max="100" id="module-progress" hidden='1'></progress>  
+    </div><!-- /emscripten bits -->
+    <div>Everything on this page happens in the dev console.</div>
+    <script src="sqlite3.js"></script>
+    <script src="SqliteTestUtil.js"></script>
+    <script src="testing1.js"></script>
+  </body>
+</html>
@@ -0,0 +1,185 @@
+/*
+  2022-05-22
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  A basic test script for sqlite3-api.js. This file must be run in
+  main JS thread and sqlite3.js must have been loaded before it.
+*/
+(function(){
+    const T = self.SqliteTestUtil;
+    const log = console.log.bind(console);
+
+    const assert = function(condition, text) {
+        if (!condition) {
+            throw new Error('Assertion failed' + (text ? ': ' + text : ''));
+        }
+    };
+
+    const test1 = function(db,sqlite3){
+        const api = sqlite3.api;
+        log("Basic sanity tests...");
+        T.assert(db._pDb);
+        let st = db.prepare("select 3 as a");
+        //log("statement =",st);
+        T.assert(st._pStmt)
+            .assert(!st._mayGet)
+            .assert('a' === st.getColumnName(0))
+            .assert(st === db._statements[st._pStmt])
+            .assert(1===st.columnCount)
+            .assert(0===st.parameterCount)
+            .mustThrow(()=>st.bind(1,null))
+            .assert(true===st.step())
+            .assert(3 === st.get(0))
+            .mustThrow(()=>st.get(1))
+            .mustThrow(()=>st.get(0,~api.SQLITE_INTEGER))
+            .assert(3 === st.get(0,api.SQLITE_INTEGER))
+            .assert(3 === st.getInt(0))
+            .assert('3' === st.get(0,api.SQLITE_TEXT))
+            .assert('3' === st.getString(0))
+            .assert(3.0 === st.get(0,api.SQLITE_FLOAT))
+            .assert(3.0 === st.getFloat(0))
+            .assert(st.get(0,api.SQLITE_BLOB) instanceof Uint8Array)
+            .assert(st.getBlob(0) instanceof Uint8Array)
+            .assert(3 === st.get([])[0])
+            .assert(3 === st.get({}).a)
+            .assert(3 === st.getJSON(0))
+            .assert(st._mayGet)
+            .assert(false===st.step())
+            .assert(!st._mayGet)
+        ;
+        let pId = st._pStmt;
+        st.finalize();
+        T.assert(!st._pStmt)
+            .assert(!db._statements[pId]);
+
+        let list = [];
+        db.exec({
+            sql:`CREATE TABLE t(a,b);
+INSERT INTO t(a,b) VALUES(1,2),(3,4),(?,?);`,
+            multi: true,
+            saveSql: list,
+            bind: [5,6]
+        });
+        T.assert(2 === list.length);
+        //log("Exec'd SQL:", list);
+        let counter = 0, colNames = [];
+        list.length = 0;
+        db.exec("SELECT a a, b b FROM t",{
+            rowMode: 'object',
+            resultRows: list,
+            columnNames: colNames,
+            callback: function(row,stmt){
+                ++counter;
+                T.assert(row.a%2 && row.a<6);
+            }
+        });
+        T.assert(2 === colNames.length)
+            .assert('a' === colNames[0])
+            .assert(3 === counter)
+            .assert(3 === list.length);
+        list.length = 0;
+        db.exec("SELECT a a, b b FROM t",{
+            rowMode: 'array',
+            callback: function(row,stmt){
+                ++counter;
+                T.assert(Array.isArray(row))
+                    .assert(0===row[1]%2 && row[1]<7);
+            }
+        });
+        T.assert(6 === counter);
+    };
+
+    const testUDF = function(db){
+        log("Testing UDF...");
+        db.createFunction("foo",function(a,b){return a+b});
+        T.assert(7===db.selectValue("select foo(3,4)")).
+            assert(5===db.selectValue("select foo(3,?)",2)).
+            assert(5===db.selectValue("select foo(?,?)",[1,4])).
+            assert(5===db.selectValue("select foo($a,$b)",{$a:0,$b:5}));
+        db.createFunction("bar", {
+            arity: -1,
+            callback: function(){
+                var rc = 0;
+                for(let i = 0; i < arguments.length; ++i) rc += arguments[i];
+                return rc;
+            }
+        });
+
+        log("Testing DB::selectValue() w/ UDF...");
+        T.assert(0===db.selectValue("select bar()")).
+            assert(1===db.selectValue("select bar(1)")).
+            assert(3===db.selectValue("select bar(1,2)")).
+            assert(-1===db.selectValue("select bar(1,2,-4)"));
+
+        const eqApprox = function(v1,v2,factor=0.05){
+            return v1>=(v2-factor) && v1<=(v2+factor);
+        };
+        
+        T.assert('hi' === db.selectValue("select ?",'hi')).
+            assert(null===db.selectValue("select null")).
+            assert(null === db.selectValue("select ?",null)).
+            assert(null === db.selectValue("select ?",[null])).
+            assert(null === db.selectValue("select $a",{$a:null})).
+            assert(eqApprox(3.1,db.selectValue("select 3.0 + 0.1")))
+        ;
+    };
+
+    const testAttach = function(db){
+        log("Testing ATTACH...");
+        db.exec({
+            sql:[
+                "attach 'foo.db' as foo",
+                "create table foo.bar(a)",
+                "insert into foo.bar(a) values(1),(2),(3)"
+            ].join(';'),
+            multi: true
+        });
+        T.assert(2===db.selectValue('select a from foo.bar where a>1 order by a'));
+        db.exec("detach foo");
+        T.mustThrow(()=>db.exec("select * from foo.bar"));
+    };
+
+    const runTests = function(Module){
+        T.assert(Module._free instanceof Function).
+            assert(Module.allocate instanceof Function).
+            assert(Module.addFunction instanceof Function).
+            assert(Module.removeFunction instanceof Function);
+        const sqlite3 = Module.sqlite3;
+        const api = sqlite3.api;
+        const oo = sqlite3.SQLite3;
+        console.log("Loaded module:",api.sqlite3_libversion(),
+                    api.sqlite3_sourceid());
+        log("Build options:",oo.compileOptionUsed());
+        const db = new oo.DB();
+        try {
+            log("DB:",db.filename);
+            [
+                test1, testUDF, testAttach
+            ].forEach((f)=>{
+                const t = T.counter;
+                f(db, sqlite3);
+                log("Test count:",T.counter - t);
+            });
+        }finally{
+            db.close();
+        }
+        log("Total Test count:",T.counter);
+    };
+
+    initSqlite3Module(self.sqlite3TestModule).then(function(theModule){
+        /** Use a timeout so that we are (hopefully) out from
+            under the module init stack when our setup gets
+            run. Just on principle, not because we _need_ to
+            be. */
+        //console.debug("theModule =",theModule);
+        setTimeout(()=>runTests(theModule), 0);
+    });
+})();
@@ -0,0 +1,32 @@
+<!doctype html>
+<html lang="en-us">
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
+    <link rel="stylesheet" href="emscripten.css"/>
+    <link rel="stylesheet" href="testing.css"/>
+    <title>sqlite3-worker.js tests</title>
+    <style></style>
+  </head>
+  <body>
+    <header id='titlebar'><span>sqlite3-worker.js tests</span></header>
+    <!-- emscripten bits -->
+    <figure id="module-spinner">
+      <div class="spinner"></div>
+      <div class='center'><strong>Initializing app...</strong></div>
+      <div class='center'>
+        On a slow internet connection this may take a moment.  If this
+        message displays for "a long time", intialization may have
+        failed and the JavaScript console may contain clues as to why.
+      </div>
+    </figure>
+    <div class="emscripten" id="module-status">Downloading...</div>
+    <div class="emscripten">
+      <progress value="0" max="100" id="module-progress" hidden='1'></progress>  
+    </div><!-- /emscripten bits -->
+    <div>Everything on this page happens in the dev console.</div>
+    <script src="testing-common.js"></script>
+    <script src="testing2.js"></script>
+  </body>
+</html>
@@ -0,0 +1,235 @@
+/*
+  2022-05-22
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  A basic test script for sqlite3-worker.js.
+*/
+(function(){
+    const T = self.SqliteTestUtil;
+    const SW = new Worker("sqlite3-worker.js");
+    /** Posts a worker message as {type:type, data:data}. */
+    const wMsg = function(type,data){
+        SW.postMessage({type, data});
+        return SW;
+    };
+    const log = console.log.bind(console);
+    const warn = console.warn.bind(console);
+    const error = console.error.bind(console);
+
+    SW.onerror = function(event){
+        error("onerror",event);
+    };
+
+    /**
+       A queue for callbacks which are to be run in response to async
+       DB commands. See the notes in runTests() for why we need
+       this. The event-handling plumbing of this file requires that
+       any DB command which includes a `messageId` property also have
+       a queued callback entry, as the existence of that property in
+       response payloads is how it knows whether or not to shift an
+       entry off of the queue.
+    */
+    const MsgHandlerQueue = {
+        queue: [],
+        id: 0,
+        push: function(type,callback){
+            this.queue.push(callback);
+            return type + '-' + (++this.id);
+        },
+        shift: function(){
+            return this.queue.shift();
+        }
+    };
+
+    const testCount = ()=>log("Total test count:",T.counter);
+
+    const runOneTest = function(eventType, eventData, callback){
+        T.assert(eventData && 'object'===typeof eventData);
+        /* ^^^ that is for the testing and messageId-related code, not
+           a hard requirement of all of the Worker-exposed APIs. */
+        eventData.messageId = MsgHandlerQueue.push(eventType,function(ev){
+            log("runOneTest",eventType,"result",ev.data);
+            if(callback instanceof Function){
+                callback(ev);
+                testCount();
+            }
+        });
+        wMsg(eventType, eventData);
+    };
+
+    /** Methods which map directly to onmessage() event.type keys.
+        They get passed the inbound event.data. */
+    const dbMsgHandler = {
+        open: function(ev){
+            log("open result",ev.data);
+        },
+        exec: function(ev){
+            log("exec result",ev.data);
+        },
+        export: function(ev){
+            log("exec result",ev.data);
+        },
+        error: function(ev){
+            error("ERROR from the worker:",ev.data);
+        },
+        resultRowTest1: function f(ev){
+            if(undefined === f.counter) f.counter = 0;
+            if(ev.data) ++f.counter;
+            //log("exec() result row:",ev.data);
+            T.assert(null===ev.data || 'number' === typeof ev.data.b);
+        }
+    };
+
+    const runTests = function(){
+        const mustNotReach = ()=>{
+            throw new Error("This is not supposed to be reached.");
+        };
+        /**
+           "The problem" now is that the test results are async. We
+           know, however, that the messages posted to the worker will
+           be processed in the order they are passed to it, so we can
+           create a queue of callbacks to handle them. The problem
+           with that approach is that it's not error-handling
+           friendly, in that an error can cause us to bypass a result
+           handler queue entry. We have to perform some extra
+           acrobatics to account for that.
+        */
+        runOneTest('open', {filename:'testing2.sqlite3'}, function(ev){
+            //log("open result",ev);
+            T.assert('testing2.sqlite3'===ev.data.filename)
+                .assert(ev.data.messageId);
+        });
+        runOneTest('exec',{
+            sql: ["create table t(a,b)",
+                  "insert into t(a,b) values(1,2),(3,4),(5,6)"
+                 ].join(';'),
+            multi: true,
+            resultRows: [], columnNames: []
+        }, function(ev){
+            ev = ev.data;
+            T.assert(0===ev.resultRows.length)
+                .assert(0===ev.columnNames.length);
+        });
+        runOneTest('exec',{
+            sql: 'select a a, b b from t order by a',
+            resultRows: [], columnNames: [],
+        }, function(ev){
+            ev = ev.data;
+            T.assert(3===ev.resultRows.length)
+                .assert(1===ev.resultRows[0][0])
+                .assert(6===ev.resultRows[2][1])
+                .assert(2===ev.columnNames.length)
+                .assert('b'===ev.columnNames[1]);
+        });
+        runOneTest('exec',{
+            sql: 'select a a, b b from t order by a',
+            resultRows: [], columnNames: [],
+            rowMode: 'object'
+        }, function(ev){
+            ev = ev.data;
+            T.assert(3===ev.resultRows.length)
+                .assert(1===ev.resultRows[0].a)
+                .assert(6===ev.resultRows[2].b)
+        });
+        runOneTest('exec',{sql:'intentional_error'}, mustNotReach);
+        // Ensure that the message-handler queue survives ^^^ that error...
+        runOneTest('exec',{
+            sql:'select 1',
+            resultRows: [],
+            //rowMode: 'array', // array is the default in the Worker interface
+        }, function(ev){
+            ev = ev.data;
+            T.assert(1 === ev.resultRows.length)
+                .assert(1 === ev.resultRows[0][0]);
+        });
+        runOneTest('exec',{
+            sql: 'select a a, b b from t order by a',
+            callback: 'resultRowTest1',
+            rowMode: 'object'
+        }, function(ev){
+            T.assert(3===dbMsgHandler.resultRowTest1.counter);
+            dbMsgHandler.resultRowTest1.counter = 0;
+        });
+        runOneTest('exec',{sql: 'delete from t where a>3'});
+        runOneTest('exec',{
+            sql: 'select count(a) from t',
+            resultRows: []
+        },function(ev){
+            ev = ev.data;
+            T.assert(1===ev.resultRows.length)
+                .assert(2===ev.resultRows[0][0]);
+        });
+        runOneTest('export',{}, function(ev){
+            ev = ev.data;
+            T.assert('string' === typeof ev.filename)
+                .assert(ev.buffer instanceof Uint8Array)
+                .assert(ev.buffer.length > 1024)
+                .assert('application/x-sqlite3' === ev.mimetype);
+        });
+
+        /***** close() tests must come last. *****/
+        runOneTest('close',{unlink:true},function(ev){
+            ev = ev.data;
+            T.assert('string' === typeof ev.filename);
+        });
+        runOneTest('close',{unlink:true},function(ev){
+            ev = ev.data;
+            T.assert(undefined === ev.filename);
+        });
+    };
+
+    SW.onmessage = function(ev){
+        if(!ev.data || 'object'!==typeof ev.data){
+            warn("Unknown sqlite3-worker message type:",ev);
+            return;
+        }
+        ev = ev.data/*expecting a nested object*/;
+        //log("main window onmessage:",ev);
+        if(ev.data && ev.data.messageId){
+            /* We're expecting a queued-up callback handler. */
+            const f = MsgHandlerQueue.shift();
+            if('error'===ev.type){
+                dbMsgHandler.error(ev);
+                return;
+            }
+            T.assert(f instanceof Function);
+            f(ev);
+            return;
+        }
+        switch(ev.type){
+            case 'sqlite3-api':
+                switch(ev.data){
+                    case 'loaded':
+                        log("Message:",ev); return;
+                    case 'ready':
+                        log("Message:",ev);
+                        self.sqlite3TestModule.setStatus(null);
+                        setTimeout(runTests, 0);
+                        return;
+                    default:
+                        warn("Unknown sqlite3-api message type:",ev);
+                        return;
+                }
+            default:
+                if(dbMsgHandler.hasOwnProperty(ev.type)){
+                    try{dbMsgHandler[ev.type](ev);}
+                    catch(err){
+                        error("Exception while handling db result message",
+                              ev,":",err);
+                    }
+                    return;
+                }
+                warn("Unknown sqlite3-api message type:",ev);
+        }
+    };
+
+    log("Init complete, but async init bits may still be running.");
+})();
@@ -308,6 +308,12 @@
  SQLITE_EXTENSION_INIT1
 #endif

+typedef struct Fts3HashWrapper Fts3HashWrapper;
+struct Fts3HashWrapper {
+  Fts3Hash hash;                  /* Hash table */
+  int nRef;                       /* Number of pointers to this object */
+};
+
 static int fts3EvalNext(Fts3Cursor *pCsr);
 static int fts3EvalStart(Fts3Cursor *pCsr);
 static int fts3TermSegReaderCursor(
@@ -1172,7 +1178,7 @@ static int fts3InitVtab(
  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
  char **pzErr                    /* Write any error message here */
 ){
-  Fts3Hash *pHash = (Fts3Hash *)pAux;
+  Fts3Hash *pHash = &((Fts3HashWrapper*)pAux)->hash;
  Fts3Table *p = 0;               /* Pointer to allocated vtab */
  int rc = SQLITE_OK;             /* Return code */
  int i;                          /* Iterator variable */
@@ -3974,8 +3980,13 @@ static int fts3ShadowName(const char *zName){
  return 0;
 }

+static int fts3ShadowName2(sqlite3_vtab *pVtab, const char *zName){
+  UNUSED_PARAMETER(pVtab);
+  return fts3ShadowName(zName);
+}
+
 static const sqlite3_module fts3Module = {
-  /* iVersion      */ 3,
+  /* iVersion      */ 4,
  /* xCreate       */ fts3CreateMethod,
  /* xConnect      */ fts3ConnectMethod,
  /* xBestIndex    */ fts3BestIndexMethod,
@@ -3994,11 +4005,12 @@ static const sqlite3_module fts3Module = {
  /* xCommit       */ fts3CommitMethod,
  /* xRollback     */ fts3RollbackMethod,
  /* xFindFunction */ fts3FindFunctionMethod,
-  /* xRename */       fts3RenameMethod,
+  /* xRename       */ fts3RenameMethod,
  /* xSavepoint    */ fts3SavepointMethod,
  /* xRelease      */ fts3ReleaseMethod,
  /* xRollbackTo   */ fts3RollbackToMethod,
  /* xShadowName   */ fts3ShadowName,
+  /* xShadowName2  */ fts3ShadowName2
 };

 /*
@@ -4007,9 +4019,12 @@ static const sqlite3_module fts3Module = {
 ** allocated for the tokenizer hash table.
 */
 static void hashDestroy(void *p){
-  Fts3Hash *pHash = (Fts3Hash *)p;
-  sqlite3Fts3HashClear(pHash);
-  sqlite3_free(pHash);
+  Fts3HashWrapper *pHash = (Fts3HashWrapper *)p;
+  pHash->nRef--;
+  if( pHash->nRef<=0 ){
+    sqlite3Fts3HashClear(&pHash->hash);
+    sqlite3_free(pHash);
+  }
 }

 /*
@@ -4039,7 +4054,7 @@ void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
 */
 int sqlite3Fts3Init(sqlite3 *db){
  int rc = SQLITE_OK;
-  Fts3Hash *pHash = 0;
+  Fts3HashWrapper *pHash = 0;
  const sqlite3_tokenizer_module *pSimple = 0;
  const sqlite3_tokenizer_module *pPorter = 0;
 #ifndef SQLITE_DISABLE_FTS3_UNICODE
@@ -4067,23 +4082,24 @@ int sqlite3Fts3Init(sqlite3 *db){
  sqlite3Fts3PorterTokenizerModule(&pPorter);

  /* Allocate and initialize the hash-table used to store tokenizers. */
-  pHash = sqlite3_malloc(sizeof(Fts3Hash));
+  pHash = sqlite3_malloc(sizeof(Fts3HashWrapper));
  if( !pHash ){
    rc = SQLITE_NOMEM;
  }else{
-    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
+    sqlite3Fts3HashInit(&pHash->hash, FTS3_HASH_STRING, 1);
+    pHash->nRef = 0;
  }

  /* Load the built-in tokenizers into the hash table */
  if( rc==SQLITE_OK ){
-    if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
-     || sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter) 
+    if( sqlite3Fts3HashInsert(&pHash->hash, "simple", 7, (void *)pSimple)
+     || sqlite3Fts3HashInsert(&pHash->hash, "porter", 7, (void *)pPorter) 

 #ifndef SQLITE_DISABLE_FTS3_UNICODE
-     || sqlite3Fts3HashInsert(pHash, "unicode61", 10, (void *)pUnicode) 
+     || sqlite3Fts3HashInsert(&pHash->hash, "unicode61", 10, (void *)pUnicode) 
 #endif
 #ifdef SQLITE_ENABLE_ICU
-     || (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
+     || (pIcu && sqlite3Fts3HashInsert(&pHash->hash, "icu", 4, (void *)pIcu))
 #endif
    ){
      rc = SQLITE_NOMEM;
@@ -4092,7 +4108,7 @@ int sqlite3Fts3Init(sqlite3 *db){

 #ifdef SQLITE_TEST
  if( rc==SQLITE_OK ){
-    rc = sqlite3Fts3ExprInitTestInterface(db, pHash);
+    rc = sqlite3Fts3ExprInitTestInterface(db, &pHash->hash);
  }
 #endif

@@ -4101,23 +4117,26 @@ int sqlite3Fts3Init(sqlite3 *db){
  ** module with sqlite.
  */
  if( SQLITE_OK==rc 
-   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
+   && SQLITE_OK==(rc=sqlite3Fts3InitHashTable(db,&pHash->hash,"fts3_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
  ){
+    pHash->nRef++;
    rc = sqlite3_create_module_v2(
        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
    );
    if( rc==SQLITE_OK ){
+      pHash->nRef++;
      rc = sqlite3_create_module_v2(
-          db, "fts4", &fts3Module, (void *)pHash, 0
+          db, "fts4", &fts3Module, (void *)pHash, hashDestroy
      );
    }
    if( rc==SQLITE_OK ){
-      rc = sqlite3Fts3InitTok(db, (void *)pHash);
+      pHash->nRef++;
+      rc = sqlite3Fts3InitTok(db, (void *)pHash, hashDestroy);
    }
    return rc;
  }
@@ -4126,7 +4145,7 @@ int sqlite3Fts3Init(sqlite3 *db){
  /* An error has occurred. Delete the hash table and return the error code. */
  assert( rc!=SQLITE_OK );
  if( pHash ){
-    sqlite3Fts3HashClear(pHash);
+    sqlite3Fts3HashClear(&pHash->hash);
    sqlite3_free(pHash);
  }
  return rc;
@@ -4295,8 +4314,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
  char *aPoslist = 0;             /* Position list for deferred tokens */
  int nPoslist = 0;               /* Number of bytes in aPoslist */
  int iPrev = -1;                 /* Token number of previous deferred token */
-
-  assert( pPhrase->doclist.bFreeList==0 );
+  char *aFree = (pPhrase->doclist.bFreeList ? pPhrase->doclist.pList : 0);

  for(iToken=0; iToken<pPhrase->nToken; iToken++){
    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
@@ -4310,6 +4328,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){

      if( pList==0 ){
        sqlite3_free(aPoslist);
+        sqlite3_free(aFree);
        pPhrase->doclist.pList = 0;
        pPhrase->doclist.nList = 0;
        return SQLITE_OK;
@@ -4330,6 +4349,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
        nPoslist = (int)(aOut - aPoslist);
        if( nPoslist==0 ){
          sqlite3_free(aPoslist);
+          sqlite3_free(aFree);
          pPhrase->doclist.pList = 0;
          pPhrase->doclist.nList = 0;
          return SQLITE_OK;
@@ -4369,6 +4389,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
      }
      
      pPhrase->doclist.pList = aOut;
+      assert( p1 && p2 );
      if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){
        pPhrase->doclist.bFreeList = 1;
        pPhrase->doclist.nList = (int)(aOut - pPhrase->doclist.pList);
@@ -4381,6 +4402,7 @@ static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
    }
  }

+  if( pPhrase->doclist.pList!=aFree ) sqlite3_free(aFree);
  return SQLITE_OK;
 }
 #endif /* SQLITE_DISABLE_FTS4_DEFERRED */
@@ -4473,7 +4495,7 @@ void sqlite3Fts3DoclistPrev(

  assert( nDoclist>0 );
  assert( *pbEof==0 );
-  assert( p || *piDocid==0 );
+  assert_fts3_nc( p || *piDocid==0 );
  assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) );

  if( p==0 ){
@@ -5337,8 +5359,8 @@ static void fts3EvalNextRow(
        Fts3Expr *pRight = pExpr->pRight;
        sqlite3_int64 iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);

-        assert( pLeft->bStart || pLeft->iDocid==pRight->iDocid );
-        assert( pRight->bStart || pLeft->iDocid==pRight->iDocid );
+        assert_fts3_nc( pLeft->bStart || pLeft->iDocid==pRight->iDocid );
+        assert_fts3_nc( pRight->bStart || pLeft->iDocid==pRight->iDocid );

        if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){
          fts3EvalNextRow(pCsr, pLeft, pRc);
@@ -5555,11 +5577,10 @@ static int fts3EvalTestExpr(

      default: {
 #ifndef SQLITE_DISABLE_FTS4_DEFERRED
-        if( pCsr->pDeferred 
-         && (pExpr->iDocid==pCsr->iPrevId || pExpr->bDeferred)
-        ){
+        if( pCsr->pDeferred && (pExpr->bDeferred || (
+            pExpr->iDocid==pCsr->iPrevId && pExpr->pPhrase->doclist.pList
+        ))){
          Fts3Phrase *pPhrase = pExpr->pPhrase;
-          assert( pExpr->bDeferred || pPhrase->doclist.bFreeList==0 );
          if( pExpr->bDeferred ){
            fts3EvalInvalidatePoslist(pPhrase);
          }
@@ -5976,6 +5997,9 @@ int sqlite3Fts3EvalPhrasePoslist(
        if( bEofSave==0 && pNear->iDocid==iDocid ) break;
      }
      assert( rc!=SQLITE_OK || pPhrase->bIncr==0 );
+      if( rc==SQLITE_OK && pNear->bEof!=bEofSave ){
+        rc = FTS_CORRUPT_VTAB;
+      }
    }
    if( bTreeEof ){
      while( rc==SQLITE_OK && !pNear->bEof ){
@@ -621,6 +621,7 @@ void sqlite3Fts3ExprFree(Fts3Expr *);
 int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash*);
 int sqlite3Fts3InitTerm(sqlite3 *db);
 #endif
+void *sqlite3Fts3MallocZero(i64 nByte);

 int sqlite3Fts3OpenTokenizer(sqlite3_tokenizer *, int, const char *, int,
  sqlite3_tokenizer_cursor **
@@ -640,7 +641,7 @@ int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);
 int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr);

 /* fts3_tokenize_vtab.c */
-int sqlite3Fts3InitTok(sqlite3*, Fts3Hash *);
+int sqlite3Fts3InitTok(sqlite3*, Fts3Hash *, void(*xDestroy)(void*));

 /* fts3_unicode2.c (functions generated by parsing unicode text files) */
 #ifndef SQLITE_DISABLE_FTS3_UNICODE
@@ -297,6 +297,7 @@ static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
    if( fts3auxGrowStatArray(pCsr, 2) ) return SQLITE_NOMEM;
    memset(pCsr->aStat, 0, sizeof(struct Fts3auxColstats) * pCsr->nStat);
    iCol = 0;
+    rc = SQLITE_OK;

    while( i<nDoclist ){
      sqlite3_int64 v = 0;
@@ -340,6 +341,10 @@ static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
        /* State 3. The integer just read is a column number. */
        default: assert( eState==3 );
          iCol = (int)v;
+          if( iCol<1 ){
+            rc = SQLITE_CORRUPT_VTAB;
+            break;
+          }
          if( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
          pCsr->aStat[iCol+1].nDoc++;
          eState = 2;
@@ -348,7 +353,6 @@ static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
    }

    pCsr->iCol = 0;
-    rc = SQLITE_OK;
  }else{
    pCsr->isEof = 1;
  }
@@ -541,7 +545,8 @@ int sqlite3Fts3InitAux(sqlite3 *db){
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0,                           /* xRollbackTo   */
-     0                            /* xShadowName   */
+     0,                           /* xShadowName   */
+     0                            /* xShadowName2  */
  };
  int rc;                         /* Return code */

@@ -122,7 +122,7 @@ static int fts3isspace(char c){
 ** zero the memory before returning a pointer to it. If unsuccessful, 
 ** return NULL.
 */
-static void *fts3MallocZero(sqlite3_int64 nByte){
+void *sqlite3Fts3MallocZero(sqlite3_int64 nByte){
  void *pRet = sqlite3_malloc64(nByte);
  if( pRet ) memset(pRet, 0, nByte);
  return pRet;
@@ -203,7 +203,7 @@ static int getNextToken(
    rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
    if( rc==SQLITE_OK ){
      nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
-      pRet = (Fts3Expr *)fts3MallocZero(nByte);
+      pRet = (Fts3Expr *)sqlite3Fts3MallocZero(nByte);
      if( !pRet ){
        rc = SQLITE_NOMEM;
      }else{
@@ -458,7 +458,7 @@ static int getNextNode(
      if( fts3isspace(cNext) 
       || cNext=='"' || cNext=='(' || cNext==')' || cNext==0
      ){
-        pRet = (Fts3Expr *)fts3MallocZero(sizeof(Fts3Expr));
+        pRet = (Fts3Expr *)sqlite3Fts3MallocZero(sizeof(Fts3Expr));
        if( !pRet ){
          return SQLITE_NOMEM;
        }
@@ -637,7 +637,7 @@ static int fts3ExprParse(
            && p->eType==FTSQUERY_PHRASE && pParse->isNot 
        ){
          /* Create an implicit NOT operator. */
-          Fts3Expr *pNot = fts3MallocZero(sizeof(Fts3Expr));
+          Fts3Expr *pNot = sqlite3Fts3MallocZero(sizeof(Fts3Expr));
          if( !pNot ){
            sqlite3Fts3ExprFree(p);
            rc = SQLITE_NOMEM;
@@ -671,7 +671,7 @@ static int fts3ExprParse(
            /* Insert an implicit AND operator. */
            Fts3Expr *pAnd;
            assert( pRet && pPrev );
-            pAnd = fts3MallocZero(sizeof(Fts3Expr));
+            pAnd = sqlite3Fts3MallocZero(sizeof(Fts3Expr));
            if( !pAnd ){
              sqlite3Fts3ExprFree(p);
              rc = SQLITE_NOMEM;
@@ -138,9 +138,8 @@ static MatchinfoBuffer *fts3MIBufferNew(size_t nElem, const char *zMatchinfo){
                           + sizeof(MatchinfoBuffer);
  sqlite3_int64 nStr = strlen(zMatchinfo);

-  pRet = sqlite3_malloc64(nByte + nStr+1);
+  pRet = sqlite3Fts3MallocZero(nByte + nStr+1);
  if( pRet ){
-    memset(pRet, 0, nByte);
    pRet->aMatchinfo[0] = (u8*)(&pRet->aMatchinfo[1]) - (u8*)pRet;
    pRet->aMatchinfo[1+nElem] = pRet->aMatchinfo[0]
                                      + sizeof(u32)*((int)nElem+1);
@@ -544,11 +543,10 @@ static int fts3BestSnippet(
  ** the required space using malloc().
  */
  nByte = sizeof(SnippetPhrase) * nList;
-  sIter.aPhrase = (SnippetPhrase *)sqlite3_malloc64(nByte);
+  sIter.aPhrase = (SnippetPhrase *)sqlite3Fts3MallocZero(nByte);
  if( !sIter.aPhrase ){
    return SQLITE_NOMEM;
  }
-  memset(sIter.aPhrase, 0, nByte);

  /* Initialize the contents of the SnippetIter object. Then iterate through
  ** the set of phrases in the expression to populate the aPhrase[] array.
@@ -1151,9 +1149,8 @@ static int fts3MatchinfoLcs(Fts3Cursor *pCsr, MatchInfo *pInfo){
  /* Allocate and populate the array of LcsIterator objects. The array
  ** contains one element for each matchable phrase in the query.
  **/
-  aIter = sqlite3_malloc64(sizeof(LcsIterator) * pCsr->nPhrase);
+  aIter = sqlite3Fts3MallocZero(sizeof(LcsIterator) * pCsr->nPhrase);
  if( !aIter ) return SQLITE_NOMEM;
-  memset(aIter, 0, sizeof(LcsIterator) * pCsr->nPhrase);
  (void)fts3ExprIterate(pCsr->pExpr, fts3MatchinfoLcsCb, (void*)aIter);

  for(i=0; i<pInfo->nPhrase; i++){
@@ -1614,7 +1611,7 @@ void sqlite3Fts3Offsets(
  if( rc!=SQLITE_OK ) goto offsets_out;

  /* Allocate the array of TermOffset iterators. */
-  sCtx.aTerm = (TermOffset *)sqlite3_malloc64(sizeof(TermOffset)*nToken);
+  sCtx.aTerm = (TermOffset *)sqlite3Fts3MallocZero(sizeof(TermOffset)*nToken);
  if( 0==sCtx.aTerm ){
    rc = SQLITE_NOMEM;
    goto offsets_out;
@@ -1635,13 +1632,13 @@ void sqlite3Fts3Offsets(
    const char *zDoc;
    int nDoc;

-    /* Initialize the contents of sCtx.aTerm[] for column iCol. There is 
-    ** no way that this operation can fail, so the return code from
-    ** fts3ExprIterate() can be discarded.
+    /* Initialize the contents of sCtx.aTerm[] for column iCol. This 
+    ** operation may fail if the database contains corrupt records.
    */
    sCtx.iCol = iCol;
    sCtx.iTerm = 0;
-    (void)fts3ExprIterate(pCsr->pExpr, fts3ExprTermOffsetInit, (void*)&sCtx);
+    rc = fts3ExprIterate(pCsr->pExpr, fts3ExprTermOffsetInit, (void*)&sCtx);
+    if( rc!=SQLITE_OK ) goto offsets_out;

    /* Retreive the text stored in column iCol. If an SQL NULL is stored 
    ** in column iCol, jump immediately to the next iteration of the loop.
@@ -362,7 +362,8 @@ int sqlite3Fts3InitTerm(sqlite3 *db){
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0,                           /* xRollbackTo   */
-     0                            /* xShadowName   */
+     0,                           /* xShadowName   */
+     0                            /* xShadowName2  */
  };
  int rc;                         /* Return code */

@@ -420,7 +420,7 @@ static int fts3tokRowidMethod(
 ** Register the fts3tok module with database connection db. Return SQLITE_OK
 ** if successful or an error code if sqlite3_create_module() fails.
 */
-int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash){
+int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash, void(*xDestroy)(void*)){
  static const sqlite3_module fts3tok_module = {
     0,                           /* iVersion      */
     fts3tokConnectMethod,        /* xCreate       */
@@ -445,11 +445,14 @@ int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash){
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0,                           /* xRollbackTo   */
-     0                            /* xShadowName   */
+     0,                           /* xShadowName   */
+     0                            /* xShadowName2  */
  };
  int rc;                         /* Return code */

-  rc = sqlite3_create_module(db, "fts3tokenize", &fts3tok_module, (void*)pHash);
+  rc = sqlite3_create_module_v2(
+      db, "fts3tokenize", &fts3tok_module, (void*)pHash, xDestroy
+  );
  return rc;
 }

@@ -1335,8 +1335,18 @@ static int fts3SegReaderNext(
        char *aCopy;
        PendingList *pList = (PendingList *)fts3HashData(pElem);
        int nCopy = pList->nData+1;
-        pReader->zTerm = (char *)fts3HashKey(pElem);
-        pReader->nTerm = fts3HashKeysize(pElem);
+
+        int nTerm = fts3HashKeysize(pElem);
+        if( (nTerm+1)>pReader->nTermAlloc ){
+          sqlite3_free(pReader->zTerm);
+          pReader->zTerm = (char*)sqlite3_malloc((nTerm+1)*2);
+          if( !pReader->zTerm ) return SQLITE_NOMEM;
+          pReader->nTermAlloc = (nTerm+1)*2;
+        }
+        memcpy(pReader->zTerm, fts3HashKey(pElem), nTerm);
+        pReader->zTerm[nTerm] = '\0';
+        pReader->nTerm = nTerm;
+
        aCopy = (char*)sqlite3_malloc(nCopy);
        if( !aCopy ) return SQLITE_NOMEM;
        memcpy(aCopy, pList->aData, nCopy);
@@ -1589,9 +1599,7 @@ int sqlite3Fts3MsrOvfl(
 */
 void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
  if( pReader ){
-    if( !fts3SegReaderIsPending(pReader) ){
-      sqlite3_free(pReader->zTerm);
-    }
+    sqlite3_free(pReader->zTerm);
    if( !fts3SegReaderIsRootOnly(pReader) ){
      sqlite3_free(pReader->aNode);
    }
@@ -3783,7 +3791,7 @@ static int nodeReaderNext(NodeReader *p){
      return FTS_CORRUPT_VTAB;
    }
    blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
-    if( rc==SQLITE_OK ){
+    if( rc==SQLITE_OK && ALWAYS(p->term.a!=0) ){
      memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
      p->term.n = nPrefix+nSuffix;
      p->iOff += nSuffix;
@@ -3891,6 +3899,8 @@ static int fts3IncrmergePush(
          pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nPrefix);
        }
        pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nSuffix);
+        assert( nPrefix+nSuffix<=nTerm );
+        assert( nPrefix>=0 );
        memcpy(&pBlk->a[pBlk->n], &zTerm[nPrefix], nSuffix);
        pBlk->n += nSuffix;

@@ -4013,6 +4023,7 @@ static int fts3IncrmergeAppend(
  pLeaf = &pWriter->aNodeWriter[0];
  nPrefix = fts3PrefixCompress(pLeaf->key.a, pLeaf->key.n, zTerm, nTerm);
  nSuffix = nTerm - nPrefix;
+  if(nSuffix<=0 ) return FTS_CORRUPT_VTAB;

  nSpace  = sqlite3Fts3VarintLen(nPrefix);
  nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
@@ -4177,7 +4188,11 @@ static int fts3TermCmp(
  int nCmp = MIN(nLhs, nRhs);
  int res;

-  res = (nCmp ? memcmp(zLhs, zRhs, nCmp) : 0);
+  if( nCmp && ALWAYS(zLhs) && ALWAYS(zRhs) ){
+    res = memcmp(zLhs, zRhs, nCmp);
+  }else{
+    res = 0;
+  }
  if( res==0 ) res = nLhs - nRhs;

  return res;
@@ -4821,7 +4836,7 @@ static int fts3IncrmergeHintLoad(Fts3Table *p, Blob *pHint){
      if( aHint ){
        blobGrowBuffer(pHint, nHint, &rc);
        if( rc==SQLITE_OK ){
-          memcpy(pHint->a, aHint, nHint);
+          if( ALWAYS(pHint->a!=0) ) memcpy(pHint->a, aHint, nHint);
          pHint->n = nHint;
        }
      }
@@ -1,115 +0,0 @@
-#!/usr/bin/tclsh
-#
-# This script builds a single C code file holding all of FTS3 code.
-# The name of the output file is fts3amal.c.  To build this file,
-# first do:
-#
-#      make target_source
-#
-# The make target above moves all of the source code files into
-# a subdirectory named "tsrc".  (This script expects to find the files
-# there and will not work if they are not found.)
-#
-# After the "tsrc" directory has been created and populated, run
-# this script:
-#
-#      tclsh mkfts3amal.tcl
-#
-# The amalgamated FTS3 code will be written into fts3amal.c
-#
-
-# Open the output file and write a header comment at the beginning
-# of the file.
-#
-set out [open fts3amal.c w]
-set today [clock format [clock seconds] -format "%Y-%m-%d %H:%M:%S UTC" -gmt 1]
-puts $out [subst \
-{/******************************************************************************
-** This file is an amalgamation of separate C source files from the SQLite
-** Full Text Search extension 2 (fts3).  By combining all the individual C 
-** code  files into this single large file, the entire code can be compiled 
-** as a one translation unit.  This allows many compilers to do optimizations
-** that would not be possible if the files were compiled separately.  It also
-** makes the code easier to import into other projects.
-**
-** This amalgamation was generated on $today.
-*/}]
-
-# These are the header files used by FTS3.  The first time any of these 
-# files are seen in a #include statement in the C code, include the complete
-# text of the file in-line.  The file only needs to be included once.
-#
-foreach hdr {
-   fts3.h
-   fts3_hash.h
-   fts3_tokenizer.h
-   sqlite3.h
-   sqlite3ext.h
-} {
-  set available_hdr($hdr) 1
-}
-
-# 78 stars used for comment formatting.
-set s78 \
-{*****************************************************************************}
-
-# Insert a comment into the code
-#
-proc section_comment {text} {
-  global out s78
-  set n [string length $text]
-  set nstar [expr {60 - $n}]
-  set stars [string range $s78 0 $nstar]
-  puts $out "/************** $text $stars/"
-}
-
-# Read the source file named $filename and write it into the
-# sqlite3.c output file.  If any #include statements are seen,
-# process them approprately.
-#
-proc copy_file {filename} {
-  global seen_hdr available_hdr out
-  set tail [file tail $filename]
-  section_comment "Begin file $tail"
-  set in [open $filename r]
-  while {![eof $in]} {
-    set line [gets $in]
-    if {[regexp {^#\s*include\s+["<]([^">]+)[">]} $line all hdr]} {
-      if {[info exists available_hdr($hdr)]} {
-        if {$available_hdr($hdr)} {
-          section_comment "Include $hdr in the middle of $tail"
-          copy_file tsrc/$hdr
-          section_comment "Continuing where we left off in $tail"
-        }
-      } elseif {![info exists seen_hdr($hdr)]} {
-        set seen_hdr($hdr) 1
-        puts $out $line
-      }
-    } elseif {[regexp {^#ifdef __cplusplus} $line]} {
-      puts $out "#if 0"
-    } elseif {[regexp {^#line} $line]} {
-      # Skip #line directives.
-    } else {
-      puts $out $line
-    }
-  }
-  close $in
-  section_comment "End of $tail"
-}
-
-
-# Process the source files.  Process files containing commonly
-# used subroutines first in order to help the compiler find
-# inlining opportunities.
-#
-foreach file {
-   fts3.c
-   fts3_hash.c
-   fts3_porter.c
-   fts3_tokenizer.c
-   fts3_tokenizer1.c
-} {
-  copy_file tsrc/$file
-}
-
-close $out
@@ -108,7 +108,7 @@ extern int sqlite3_fts5_may_be_corrupt;
 ** A version of memcmp() that does not cause asan errors if one of the pointer
 ** parameters is NULL and the number of bytes to compare is zero.
 */
-#define fts5Memcmp(s1, s2, n) ((n)==0 ? 0 : memcmp((s1), (s2), (n)))
+#define fts5Memcmp(s1, s2, n) ((n)<=0 ? 0 : memcmp((s1), (s2), (n)))

 /* Mark a function parameter as unused, to suppress nuisance compiler
 ** warnings. */
@@ -66,7 +66,6 @@ void sqlite3Fts5BufferAppendBlob(
  u32 nData, 
  const u8 *pData
 ){
-  assert_nc( *pRc || nData>=0 );
  if( nData ){
    if( fts5BufferGrow(pRc, pBuf, nData) ) return;
    memcpy(&pBuf->p[pBuf->n], pData, nData);
@@ -178,7 +177,6 @@ int sqlite3Fts5PoslistNext64(
    i64 iOff = *piOff;
    u32 iVal;
    fts5FastGetVarint32(a, i, iVal);
-    assert( iVal>=0 );
    if( iVal<=1 ){
      if( iVal==0 ){
        *pi = i;
@@ -562,6 +562,7 @@ int sqlite3Fts5ConfigParse(
    z = fts5ConfigSkipWhitespace(z);
    if( z && *z=='=' ){
      bOption = 1;
+      assert( zOne!=0 );
      z++;
      if( bMustBeCol ) z = 0;
    }
@@ -578,7 +579,11 @@ int sqlite3Fts5ConfigParse(
        rc = SQLITE_ERROR;
      }else{
        if( bOption ){
-          rc = fts5ConfigParseSpecial(pGlobal, pRet, zOne, zTwo?zTwo:"", pzErr);
+          rc = fts5ConfigParseSpecial(pGlobal, pRet, 
+            ALWAYS(zOne)?zOne:"",
+            zTwo?zTwo:"",
+            pzErr
+          );
        }else{
          rc = fts5ConfigParseColumn(pRet, zOne, zTwo, pzErr);
          zOne = 0;
@@ -1627,6 +1627,9 @@ Fts5ExprNearset *sqlite3Fts5ParseNearset(
  }else{
    if( pRet->nPhrase>0 ){
      Fts5ExprPhrase *pLast = pRet->apPhrase[pRet->nPhrase-1];
+      assert( pParse!=0 );
+      assert( pParse->apPhrase!=0 );
+      assert( pParse->nPhrase>=2 );
      assert( pLast==pParse->apPhrase[pParse->nPhrase-2] );
      if( pPhrase->nTerm==0 ){
        fts5ExprPhraseFree(pPhrase);
@@ -1875,7 +1878,7 @@ int sqlite3Fts5ExprClonePhrase(
    sCtx.pPhrase = sqlite3Fts5MallocZero(&rc, sizeof(Fts5ExprPhrase));
  }

-  if( rc==SQLITE_OK ){
+  if( rc==SQLITE_OK && ALWAYS(sCtx.pPhrase) ){
    /* All the allocations succeeded. Put the expression object together. */
    pNew->pIndex = pExpr->pIndex;
    pNew->pConfig = pExpr->pConfig;
@@ -2856,6 +2859,15 @@ struct Fts5PoslistPopulator {
  int bMiss;
 };

+/*
+** Clear the position lists associated with all phrases in the expression
+** passed as the first argument. Argument bLive is true if the expression
+** might be pointing to a real entry, otherwise it has just been reset.
+**
+** At present this function is only used for detail=col and detail=none
+** fts5 tables. This implies that all phrases must be at most 1 token
+** in size, as phrase matches are not supported without detail=full.
+*/
 Fts5PoslistPopulator *sqlite3Fts5ExprClearPoslists(Fts5Expr *pExpr, int bLive){
  Fts5PoslistPopulator *pRet;
  pRet = sqlite3_malloc64(sizeof(Fts5PoslistPopulator)*pExpr->nPhrase);
@@ -2865,7 +2877,7 @@ Fts5PoslistPopulator *sqlite3Fts5ExprClearPoslists(Fts5Expr *pExpr, int bLive){
    for(i=0; i<pExpr->nPhrase; i++){
      Fts5Buffer *pBuf = &pExpr->apExprPhrase[i]->poslist;
      Fts5ExprNode *pNode = pExpr->apExprPhrase[i]->pNode;
-      assert( pExpr->apExprPhrase[i]->nTerm==1 );
+      assert( pExpr->apExprPhrase[i]->nTerm<=1 );
      if( bLive && 
          (pBuf->n==0 || pNode->iRowid!=pExpr->pRoot->iRowid || pNode->bEof)
      ){
@@ -356,7 +356,7 @@ int sqlite3Fts5HashWrite(
      p->bContent = 1;
    }else{
      /* Append a new column value, if necessary */
-      assert( iCol>=p->iCol );
+      assert_nc( iCol>=p->iCol );
      if( iCol!=p->iCol ){
        if( pHash->eDetail==FTS5_DETAIL_FULL ){
          pPtr[p->nData++] = 0x01;
@@ -296,7 +296,7 @@ struct Fts5Index {
  sqlite3_stmt *pWriter;          /* "INSERT ... %_data VALUES(?,?)" */
  sqlite3_stmt *pDeleter;         /* "DELETE FROM %_data ... id>=? AND id<=?" */
  sqlite3_stmt *pIdxWriter;       /* "INSERT ... %_idx VALUES(?,?,?,?)" */
-  sqlite3_stmt *pIdxDeleter;      /* "DELETE FROM %_idx WHERE segid=? */
+  sqlite3_stmt *pIdxDeleter;      /* "DELETE FROM %_idx WHERE segid=?" */
  sqlite3_stmt *pIdxSelect;
  int nRead;                      /* Total number of blocks read */

@@ -600,8 +600,11 @@ static int fts5BufferCompareBlob(
 **     res = *pLeft - *pRight
 */
 static int fts5BufferCompare(Fts5Buffer *pLeft, Fts5Buffer *pRight){
-  int nCmp = MIN(pLeft->n, pRight->n);
-  int res = fts5Memcmp(pLeft->p, pRight->p, nCmp);
+  int nCmp, res;
+  nCmp = MIN(pLeft->n, pRight->n);
+  assert( nCmp<=0 || pLeft->p!=0 );
+  assert( nCmp<=0 || pRight->p!=0 );
+  res = fts5Memcmp(pLeft->p, pRight->p, nCmp);
  return (res==0 ? (pLeft->n - pRight->n) : res);
 }

@@ -847,7 +850,7 @@ int sqlite3Fts5StructureTest(Fts5Index *p, void *pStruct){
 static void fts5StructureMakeWritable(int *pRc, Fts5Structure **pp){
  Fts5Structure *p = *pp;
  if( *pRc==SQLITE_OK && p->nRef>1 ){
-    int nByte = sizeof(Fts5Structure)+(p->nLevel-1)*sizeof(Fts5StructureLevel);
+    i64 nByte = sizeof(Fts5Structure)+(p->nLevel-1)*sizeof(Fts5StructureLevel);
    Fts5Structure *pNew;
    pNew = (Fts5Structure*)sqlite3Fts5MallocZero(pRc, nByte);
    if( pNew ){
@@ -1876,8 +1879,12 @@ static void fts5SegIterReverseNewPage(Fts5Index *p, Fts5SegIter *pIter){
        int iRowidOff;
        iRowidOff = fts5LeafFirstRowidOff(pNew);
        if( iRowidOff ){
-          pIter->pLeaf = pNew;
-          pIter->iLeafOffset = iRowidOff;
+          if( iRowidOff>=pNew->szLeaf ){
+            p->rc = FTS5_CORRUPT;
+          }else{
+            pIter->pLeaf = pNew;
+            pIter->iLeafOffset = iRowidOff;
+          }
        }
      }

@@ -2278,21 +2285,20 @@ static void fts5LeafSeek(
  Fts5SegIter *pIter,             /* Iterator to seek */
  const u8 *pTerm, int nTerm      /* Term to search for */
 ){
-  int iOff;
+  u32 iOff;
  const u8 *a = pIter->pLeaf->p;
-  int szLeaf = pIter->pLeaf->szLeaf;
-  int n = pIter->pLeaf->nn;
+  u32 n = (u32)pIter->pLeaf->nn;

  u32 nMatch = 0;
  u32 nKeep = 0;
  u32 nNew = 0;
  u32 iTermOff;
-  int iPgidx;                     /* Current offset in pgidx */
+  u32 iPgidx;                     /* Current offset in pgidx */
  int bEndOfPage = 0;

  assert( p->rc==SQLITE_OK );

-  iPgidx = szLeaf;
+  iPgidx = (u32)pIter->pLeaf->szLeaf;
  iPgidx += fts5GetVarint32(&a[iPgidx], iTermOff);
  iOff = iTermOff;
  if( iOff>n ){
@@ -2358,15 +2364,15 @@ static void fts5LeafSeek(
      if( pIter->pLeaf==0 ) return;
      a = pIter->pLeaf->p;
      if( fts5LeafIsTermless(pIter->pLeaf)==0 ){
-        iPgidx = pIter->pLeaf->szLeaf;
+        iPgidx = (u32)pIter->pLeaf->szLeaf;
        iPgidx += fts5GetVarint32(&pIter->pLeaf->p[iPgidx], iOff);
-        if( iOff<4 || iOff>=pIter->pLeaf->szLeaf ){
+        if( iOff<4 || (i64)iOff>=pIter->pLeaf->szLeaf ){
          p->rc = FTS5_CORRUPT;
          return;
        }else{
          nKeep = 0;
          iTermOff = iOff;
-          n = pIter->pLeaf->nn;
+          n = (u32)pIter->pLeaf->nn;
          iOff += fts5GetVarint32(&a[iOff], nNew);
          break;
        }
@@ -3166,7 +3172,11 @@ static void fts5SegiterPoslist(
  Fts5Colset *pColset,
  Fts5Buffer *pBuf
 ){
+  assert( pBuf!=0 );
+  assert( pSeg!=0 );
  if( 0==fts5BufferGrow(&p->rc, pBuf, pSeg->nPos+FTS5_DATA_ZERO_PADDING) ){
+    assert( pBuf->p!=0 );
+    assert( pBuf->nSpace >= pBuf->n+pSeg->nPos+FTS5_DATA_ZERO_PADDING );
    memset(&pBuf->p[pBuf->n+pSeg->nPos], 0, FTS5_DATA_ZERO_PADDING);
    if( pColset==0 ){
      fts5ChunkIterate(p, pSeg, (void*)pBuf, fts5PoslistCallback);
@@ -3390,6 +3400,7 @@ static void fts5IterSetOutputs_Full(Fts5Iter *pIter, Fts5SegIter *pSeg){
 }

 static void fts5IterSetOutputCb(int *pRc, Fts5Iter *pIter){
+  assert( pIter!=0 || (*pRc)!=SQLITE_OK );
  if( *pRc==SQLITE_OK ){
    Fts5Config *pConfig = pIter->pIndex->pConfig;
    if( pConfig->eDetail==FTS5_DETAIL_NONE ){
@@ -3461,7 +3472,10 @@ static void fts5MultiIterNew(
    }
  }
  *ppOut = pNew = fts5MultiIterAlloc(p, nSeg);
-  if( pNew==0 ) return;
+  if( pNew==0 ){
+    assert( p->rc!=SQLITE_OK );
+    goto fts5MultiIterNew_post_check;
+  }
  pNew->bRev = (0!=(flags & FTS5INDEX_QUERY_DESC));
  pNew->bSkipEmpty = (0!=(flags & FTS5INDEX_QUERY_SKIPEMPTY));
  pNew->pColset = pColset;
@@ -3525,6 +3539,10 @@ static void fts5MultiIterNew(
    fts5MultiIterFree(pNew);
    *ppOut = 0;
  }
+
+fts5MultiIterNew_post_check:
+  assert( (*ppOut)!=0 || p->rc!=SQLITE_OK );
+  return;
 }

 /*
@@ -3572,7 +3590,8 @@ static void fts5MultiIterNew2(
 ** False otherwise.
 */
 static int fts5MultiIterEof(Fts5Index *p, Fts5Iter *pIter){
-  assert( p->rc 
+  assert( pIter!=0 || p->rc!=SQLITE_OK );
+  assert( p->rc!=SQLITE_OK
      || (pIter->aSeg[ pIter->aFirst[1].iFirst ].pLeaf==0)==pIter->base.bEof 
  );
  return (p->rc || pIter->base.bEof);
@@ -4376,6 +4395,7 @@ static void fts5IndexMergeLevel(
  ** and last leaf page number at the same time.  */
  fts5WriteFinish(p, &writer, &pSeg->pgnoLast);

+  assert( pIter!=0 || p->rc!=SQLITE_OK );
  if( fts5MultiIterEof(p, pIter) ){
    int i;

@@ -5545,7 +5565,7 @@ int sqlite3Fts5IndexQuery(
  if( sqlite3Fts5BufferSize(&p->rc, &buf, nToken+1)==0 ){
    int iIdx = 0;                 /* Index to search */
    int iPrefixIdx = 0;           /* +1 prefix index */
-    if( nToken ) memcpy(&buf.p[1], pToken, nToken);
+    if( nToken>0 ) memcpy(&buf.p[1], pToken, nToken);

    /* Figure out which index to search and set iIdx accordingly. If this
    ** is a prefix query for which there is no prefix index, set iIdx to
@@ -5586,11 +5606,15 @@ int sqlite3Fts5IndexQuery(
      /* Scan multiple terms in the main index */
      int bDesc = (flags & FTS5INDEX_QUERY_DESC)!=0;
      fts5SetupPrefixIter(p, bDesc, iPrefixIdx, buf.p, nToken+1, pColset,&pRet);
-      assert( p->rc!=SQLITE_OK || pRet->pColset==0 );
-      fts5IterSetOutputCb(&p->rc, pRet);
-      if( p->rc==SQLITE_OK ){
-        Fts5SegIter *pSeg = &pRet->aSeg[pRet->aFirst[1].iFirst];
-        if( pSeg->pLeaf ) pRet->xSetOutputs(pRet, pSeg);
+      if( pRet==0 ){
+        assert( p->rc!=SQLITE_OK );
+      }else{
+        assert( pRet->pColset==0 );
+        fts5IterSetOutputCb(&p->rc, pRet);
+        if( p->rc==SQLITE_OK ){
+          Fts5SegIter *pSeg = &pRet->aSeg[pRet->aFirst[1].iFirst];
+          if( pSeg->pLeaf ) pRet->xSetOutputs(pRet, pSeg);
+        }
      }
    }

@@ -6203,6 +6227,7 @@ int sqlite3Fts5IndexIntegrityCheck(Fts5Index *p, u64 cksum, int bUseCksum){
  Fts5Buffer poslist = {0,0,0};   /* Buffer used to hold a poslist */
  Fts5Iter *pIter;                /* Used to iterate through entire index */
  Fts5Structure *pStruct;         /* Index structure */
+  int iLvl, iSeg;

 #ifdef SQLITE_DEBUG
  /* Used by extra internal tests only run if NDEBUG is not defined */
@@ -6213,15 +6238,16 @@ int sqlite3Fts5IndexIntegrityCheck(Fts5Index *p, u64 cksum, int bUseCksum){
  
  /* Load the FTS index structure */
  pStruct = fts5StructureRead(p);
+  if( pStruct==0 ){
+    assert( p->rc!=SQLITE_OK );
+    return fts5IndexReturn(p);
+  }

  /* Check that the internal nodes of each segment match the leaves */
-  if( pStruct ){
-    int iLvl, iSeg;
-    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
-      for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
-        Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
-        fts5IndexIntegrityCheckSegment(p, pSeg);
-      }
+  for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+    for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+      Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+      fts5IndexIntegrityCheckSegment(p, pSeg);
    }
  }

@@ -804,7 +804,7 @@ static int fts5SorterNext(Fts5Cursor *pCsr){
  rc = sqlite3_step(pSorter->pStmt);
  if( rc==SQLITE_DONE ){
    rc = SQLITE_OK;
-    CsrFlagSet(pCsr, FTS5CSR_EOF);
+    CsrFlagSet(pCsr, FTS5CSR_EOF|FTS5CSR_REQUIRE_CONTENT);
  }else if( rc==SQLITE_ROW ){
    const u8 *a;
    const u8 *aBlob;
@@ -1374,7 +1374,8 @@ static int fts5FilterMethod(
        pTab->pStorage, fts5StmtType(pCsr), &pCsr->pStmt, &pTab->p.base.zErrMsg
    );
    if( rc==SQLITE_OK ){
-      if( pCsr->ePlan==FTS5_PLAN_ROWID ){
+      if( pRowidEq!=0 ){
+        assert( pCsr->ePlan==FTS5_PLAN_ROWID );
        sqlite3_bind_value(pCsr->pStmt, 1, pRowidEq);
      }else{
        sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iFirstRowid);
@@ -2810,9 +2811,14 @@ static int fts5ShadowName(const char *zName){
  return 0;
 }

+static int fts5ShadowName2(sqlite3_vtab *pVtab, const char *zName){
+  UNUSED_PARAMETER(pVtab);
+  return fts5ShadowName(zName);
+}
+
 static int fts5Init(sqlite3 *db){
  static const sqlite3_module fts5Mod = {
-    /* iVersion      */ 3,
+    /* iVersion      */ 4,
    /* xCreate       */ fts5CreateMethod,
    /* xConnect      */ fts5ConnectMethod,
    /* xBestIndex    */ fts5BestIndexMethod,
@@ -2835,7 +2841,8 @@ static int fts5Init(sqlite3 *db){
    /* xSavepoint    */ fts5SavepointMethod,
    /* xRelease      */ fts5ReleaseMethod,
    /* xRollbackTo   */ fts5RollbackToMethod,
-    /* xShadowName   */ fts5ShadowName
+    /* xShadowName   */ fts5ShadowName,
+    /* xShadowName2  */ fts5ShadowName2
  };

  int rc;
@@ -417,12 +417,16 @@ static int fts5StorageDeleteFromIndex(
    if( pConfig->abUnindexed[iCol-1]==0 ){
      const char *zText;
      int nText;
+      assert( pSeek==0 || apVal==0 );
+      assert( pSeek!=0 || apVal!=0 );
      if( pSeek ){
        zText = (const char*)sqlite3_column_text(pSeek, iCol);
        nText = sqlite3_column_bytes(pSeek, iCol);
-      }else{
+      }else if( ALWAYS(apVal) ){
        zText = (const char*)sqlite3_value_text(apVal[iCol-1]);
        nText = sqlite3_value_bytes(apVal[iCol-1]);
+      }else{
+        continue;
      }
      ctx.szCol = 0;
      rc = sqlite3Fts5Tokenize(pConfig, FTS5_TOKENIZE_DOCUMENT, 
@@ -1058,8 +1062,9 @@ int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol){

  assert( p->pConfig->bColumnsize );
  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP_DOCSIZE, &pLookup, 0);
-  if( rc==SQLITE_OK ){
+  if( pLookup ){
    int bCorrupt = 1;
+    assert( rc==SQLITE_OK );
    sqlite3_bind_int64(pLookup, 1, iRowid);
    if( SQLITE_ROW==sqlite3_step(pLookup) ){
      const u8 *aBlob = sqlite3_column_blob(pLookup, 0);
@@ -1072,6 +1077,8 @@ int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol){
    if( bCorrupt && rc==SQLITE_OK ){
      rc = FTS5_CORRUPT;
    }
+  }else{
+    assert( rc!=SQLITE_OK );
  }

  return rc;
@@ -472,7 +472,8 @@ int sqlite3Fts5TestRegisterTok(sqlite3 *db, fts5_api *pApi){
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0,                           /* xRollbackTo   */
-     0                            /* xShadowName   */
+     0,                           /* xShadowName   */
+     0                            /* xShadowName2  */
  };
  int rc;                         /* Return code */

@@ -374,7 +374,7 @@ static int fts5VocabOpenMethod(
  }

  if( rc==SQLITE_OK ){
-    int nByte = pFts5->pConfig->nCol * sizeof(i64)*2 + sizeof(Fts5VocabCursor);
+    i64 nByte = pFts5->pConfig->nCol * sizeof(i64)*2 + sizeof(Fts5VocabCursor);
    pCsr = (Fts5VocabCursor*)sqlite3Fts5MallocZero(&rc, nByte);
  }

@@ -783,7 +783,8 @@ int sqlite3Fts5VocabInit(Fts5Global *pGlobal, sqlite3 *db){
    /* xSavepoint    */ 0,
    /* xRelease      */ 0,
    /* xRollbackTo   */ 0,
-    /* xShadowName   */ 0
+    /* xShadowName   */ 0,
+    /* xShadowName2  */ 0
  };
  void *p = (void*)pGlobal;

@@ -165,7 +165,7 @@ do_execsql_test 4.0 {
 }

 do_execsql_test 5.0 {
-  CREATE VIRTUAL TABLE p1 USING fts5(a, b);
+  CREATE VIRTUAL TABLE p1 USING fts5(a, b, detail=%DETAIL%);
  INSERT INTO p1 VALUES(
    'x a a a a a a a a a a',
    'a a a a a a a a a a a a a a a a a a a x'
@@ -184,6 +184,12 @@ do_execsql_test 5.3 {
 do_execsql_test 5.4 {
  SELECT snippet(p1, 0, '[', NULL, '...', 6) FROM p1('x');
 } {{[x a a a a a...}}
+do_execsql_test 5.5 {
+  SELECT snippet(p1, 0, '[', NULL, '...', 6) FROM p1('x OR ""');
+} {{[x a a a a a...}}
+do_execsql_test 5.6 {
+  SELECT snippet(p1, 0, '[', NULL, '...', 6) FROM p1('x OR ' || x'DB');
+} {{[x a a a a a...}}

 } ;# foreach_detail_mode 

@@ -11,6 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this script is testing the FTS5 module.
 #
+# TESTRUNNER: slow

 source [file join [file dirname [info script]] fts5_common.tcl]
 set testprefix fts5ah
@@ -15366,6 +15366,160 @@ do_catchsql_test 79.2 {
  INSERT INTO t1(t1) SELECT 'merge' FROM t2;
 } {1 {query aborted}}

+#-------------------------------------------------------------------------
+reset_db
+do_test 80.0 {
+  sqlite3 db {}
+  db deserialize [decode_hexdb {
+.open --hexdb
+| size 40960 pagesize 4096 filename crash-f928a9c1ec68dd.db
+| page 1 offset 0
+|      0: 53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00   SQLite format 3.
+|     16: 10 00 01 01 00 40 20 20 00 00 00 00 00 00 00 0a   .....@  ........
+|     32: 00 00 00 00 00 00 00 00 00 00 00 0d 00 00 00 04   ................
+|     96: 00 00 00 00 0d 00 00 00 0d 0b 6e 00 0f a3 0f 4c   ..........n....L
+|    112: 0e e1 0e 81 0e 24 0d cc 0d 72 0d 1b 0c b0 0c 50   .....$...r.....P
+|    128: 0b f8 0b b3 0b 6e 00 00 00 00 00 00 00 00 00 00   .....n..........
+|   2912: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 43 0d   ..............C.
+|   2928: 06 17 11 11 08 75 74 61 62 6c 65 74 34 74 34 43   .....utablet4t4C
+|   2944: 52 45 41 54 45 20 56 49 52 54 55 41 4c 20 54 41   REATE VIRTUAL TA
+|   2960: 42 4c 45 20 74 34 20 55 53 49 4e 47 20 66 74 73   BLE t4 USING fts
+|   2976: 35 76 6f 63 61 62 28 27 74 32 27 2c 20 27 72 6f   5vocab('t2', 'ro
+|   2992: 77 27 29 43 0c 06 17 11 11 08 75 74 61 62 6c 65   w')C......utable
+|   3008: 74 33 74 33 43 52 45 41 54 45 20 56 49 52 54 55   t3t3CREATE VIRTU
+|   3024: 41 4c 20 54 41 42 4c 45 20 74 33 20 55 53 49 4e   AL TABLE t3 USIN
+|   3040: 47 20 66 74 73 35 76 6f 63 61 62 28 27 74 31 27   G fts5vocab('t1'
+|   3056: 2c 20 27 72 6f 77 27 29 56 0b 06 17 1f 1f 01 7d   , 'row')V.......
+|   3072: 74 61 62 6c 65 74 32 5f 63 6f 6e 66 69 67 74 32   tablet2_configt2
+|   3088: 5f 63 6f 6e 66 69 67 0a 43 52 45 41 54 45 20 54   _config.CREATE T
+|   3104: 41 42 4c 45 20 27 74 32 5f 63 6f 6e 66 69 67 27   ABLE 't2_config'
+|   3120: 28 6b 20 50 52 49 4d 41 52 59 20 4b 45 59 2c 20   (k PRIMARY KEY, 
+|   3136: 76 29 20 57 49 54 48 4f 55 54 20 52 4f 57 49 44   v) WITHOUT ROWID
+|   3152: 5e 0a 07 17 21 21 01 81 07 74 61 62 6c 65 74 32   ^...!!...tablet2
+|   3168: 5f 63 6f 6e 74 65 6e 74 74 32 5f 63 6f 6e 74 65   _contentt2_conte
+|   3184: 6e 74 09 43 52 45 41 54 45 20 54 41 42 4c 45 20   nt.CREATE TABLE 
+|   3200: 27 74 32 5f 63 6f 6e 74 65 6e 74 27 28 69 64 20   't2_content'(id 
+|   3216: 49 4e 54 45 47 45 52 20 50 52 49 4d 41 52 59 20   INTEGER PRIMARY 
+|   3232: 4b 45 59 2c 20 63 30 2c 20 63 31 2c 20 63 32 29   KEY, c0, c1, c2)
+|   3248: 69 09 07 17 19 19 01 81 2d 74 61 62 6c 65 74 32   i.......-tablet2
+|   3264: 5f 69 64 78 74 32 5f 69 64 78 08 43 52 45 41 54   _idxt2_idx.CREAT
+|   3280: 45 20 54 41 42 4c 45 20 27 74 32 5f 69 64 78 27   E TABLE 't2_idx'
+|   3296: 28 73 65 67 69 64 2c 20 74 65 72 6d 2c 20 70 67   (segid, term, pg
+|   3312: 6e 6f 2c 20 50 52 49 4d 41 52 59 20 4b 45 59 28   no, PRIMARY KEY(
+|   3328: 73 65 67 69 64 2c 20 74 65 72 6d 29 29 20 57 49   segid, term)) WI
+|   3344: 54 48 4f 55 54 20 52 4f 57 49 44 55 08 07 17 1b   THOUT ROWIDU....
+|   3360: 1b 01 81 01 74 61 62 6c 65 74 32 5f 64 61 74 61   ....tablet2_data
+|   3376: 74 32 5f 64 61 74 61 07 43 52 45 41 54 45 20 54   t2_data.CREATE T
+|   3392: 41 42 4c 45 20 27 74 32 5f 64 61 74 61 27 28 69   ABLE 't2_data'(i
+|   3408: 64 20 49 4e 54 45 47 45 52 20 50 52 49 4d 41 52   d INTEGER PRIMAR
+|   3424: 59 20 4b 45 59 2c 20 62 6c 6f 63 6b 20 42 4c 4f   Y KEY, block BLO
+|   3440: 42 29 58 07 07 17 11 11 08 81 1d 74 61 62 6c 65   B)X........table
+|   3456: 74 32 74 32 43 52 45 41 54 45 20 56 49 52 54 55   t2t2CREATE VIRTU
+|   3472: 41 4c 20 54 41 42 4c 45 20 74 32 20 55 53 49 4e   AL TABLE t2 USIN
+|   3488: 47 20 66 74 73 35 28 27 61 27 2c 5b 62 5d 2c 22   G fts5('a',[b],.
+|   3504: 63 22 2c 64 65 74 61 69 6c 3d 6e 6f 6e 65 2c 63   c.,detail=none,c
+|   3520: 6f 6c 75 6d 6e 73 69 7a 65 3d 30 29 56 06 06 17   olumnsize=0)V...
+|   3536: 1f 1f 01 7d 74 61 62 6c 65 74 31 5f 63 6f 6e 66   ....tablet1_conf
+|   3552: 69 67 74 31 5f 63 6f 6e 66 69 67 06 43 52 45 41   igt1_config.CREA
+|   3568: 54 45 20 54 41 42 4c 45 20 27 74 31 5f 63 6f 6e   TE TABLE 't1_con
+|   3584: 66 69 67 27 28 6b 20 50 52 49 4d 41 52 59 20 4b   fig'(k PRIMARY K
+|   3600: 45 59 2c 20 76 29 20 57 49 54 48 4f 55 54 20 52   EY, v) WITHOUT R
+|   3616: 4f 57 49 44 5b 05 07 17 21 21 01 81 01 74 61 62   OWID[...!!...tab
+|   3632: 6c 65 74 31 5f 64 6f 63 73 69 7a 65 74 31 5f 64   let1_docsizet1_d
+|   3648: 6f 63 73 69 7a 65 05 43 52 45 41 54 45 20 54 41   ocsize.CREATE TA
+|   3664: 42 4c 45 20 27 74 31 5f 64 6f 63 73 69 7a 65 27   BLE 't1_docsize'
+|   3680: 28 69 64 20 49 4e 54 45 47 45 52 20 50 52 49 4d   (id INTEGER PRIM
+|   3696: 41 52 59 20 4b 45 59 2c 20 73 7a 20 42 4c 4f 42   ARY KEY, sz BLOB
+|   3712: 29 5e 04 07 17 21 21 01 81 07 74 61 62 6c 65 74   )^...!!...tablet
+|   3728: 31 5f 63 6f 6e 74 65 6e 74 74 31 5f 63 6f 6e 74   1_contentt1_cont
+|   3744: 65 6e 74 04 43 52 45 41 54 45 20 54 41 42 4c 45   ent.CREATE TABLE
+|   3760: 20 27 74 31 5f 63 6f 6e 74 65 6e 74 27 28 69 64    't1_content'(id
+|   3776: 20 49 4e 54 45 47 45 52 20 50 52 49 4d 41 52 59    INTEGER PRIMARY
+|   3792: 20 4b 45 59 2c 20 63 30 2c 20 63 31 2c 20 63 32    KEY, c0, c1, c2
+|   3808: 29 69 03 07 17 19 19 01 81 2d 74 61 62 6c 65 74   )i.......-tablet
+|   3824: 31 5f 69 64 78 74 31 5f 69 64 78 03 43 52 45 41   1_idxt1_idx.CREA
+|   3840: 54 45 20 54 41 42 4c 45 20 27 74 31 5f 69 64 78   TE TABLE 't1_idx
+|   3856: 27 28 73 65 67 69 64 2c 20 74 65 72 6d 2c 20 70   '(segid, term, p
+|   3872: 67 6e 6f 2c 20 50 52 49 4d 41 52 59 20 4b 45 59   gno, PRIMARY KEY
+|   3888: 28 73 65 67 69 64 2c 20 74 65 72 6d 29 29 20 57   (segid, term)) W
+|   3904: 49 54 48 4f 55 54 20 52 4f 57 49 44 55 02 07 17   ITHOUT ROWIDU...
+|   3920: 1b 1b 01 81 01 74 61 62 6c 65 74 31 5f 64 61 74   .....tablet1_dat
+|   3936: 61 74 31 5f 64 61 74 61 02 43 52 45 41 54 45 20   at1_data.CREATE 
+|   3952: 54 41 42 4c 45 20 27 74 31 5f 64 61 74 61 27 28   TABLE 't1_data'(
+|   3968: 69 64 20 49 4e 54 45 47 45 52 20 50 52 49 4d 41   id INTEGER PRIMA
+|   3984: 52 59 20 4b 45 59 2c 20 62 6c 6f 63 6b 20 42 4c   RY KEY, block BL
+|   4000: 4f 42 29 5b 01 07 17 11 11 08 81 23 74 61 62 6c   OB)[.......#tabl
+|   4016: 65 74 31 74 31 43 52 45 41 54 45 20 56 49 52 54   et1t1CREATE VIRT
+|   4032: 55 41 4c 20 54 41 42 4c 45 20 74 31 20 55 53 49   UAL TABLE t1 USI
+|   4048: 4e 47 20 66 74 73 35 28 61 2c 62 20 75 6e 69 6e   NG fts5(a,b unin
+|   4064: 64 65 78 65 64 2c 63 2c 74 6f 6b 65 6e 69 7a 65   dexed,c,tokenize
+|   4080: 3d 22 70 6f 72 74 65 72 20 61 73 63 69 69 22 29   =.porter ascii.)
+| page 2 offset 4096
+|      0: 0d 0f 68 00 05 0f 13 00 0f e6 0f 13 0f a8 0f 7c   ..h............|
+|     16: 0f 2a 00 00 00 00 00 00 00 00 00 00 00 00 00 00   .*..............
+|   3856: 00 00 00 15 0a 03 00 30 00 00 00 00 01 03 03 00   .......0........
+|   3872: 03 01 01 01 02 01 01 03 01 01 37 8c 80 80 80 80   ..........7.....
+|   3888: 01 03 00 74 00 00 00 2e 02 30 61 03 02 02 01 01   ...t.....0a.....
+|   3904: 62 03 02 03 01 01 63 03 02 04 01 01 67 03 06 01   b.....c.....g...
+|   3920: 02 02 01 01 68 03 06 01 02 03 01 01 69 03 06 01   ....h.......i...
+|   3936: 02 04 04 06 06 06 08 08 0f ef 00 14 2a 00 00 00   ............*...
+|   3952: 00 01 02 02 00 02 01 01 01 02 01 01 25 88 80 80   ............%...
+|   3968: 80 80 01 03 00 50 00 00 00 1f 02 30 67 02 08 02   .....P.....0g...
+|   3984: 01 02 02 01 01 68 02 08 03 01 02 03 01 01 69 02   .....h........i.
+|   4000: 08 04 01 02 04 04 09 09 37 84 80 80 80 80 01 03   ........7.......
+|   4016: 00 74 00 00 00 2e 02 30 61 01 02 02 01 01 62 01   .t.....0a.....b.
+|   4032: 02 03 01 01 63 01 02 04 01 01 67 01 06 01 02 02   ....c.....g.....
+|   4048: 01 01 68 01 06 01 02 03 01 01 69 01 06 01 02 04   ..h.......i.....
+|   4064: 04 06 06 06 08 08 07 01 03 00 14 03 09 00 09 00   ................
+|   4080: 00 00 11 24 00 00 00 00 01 01 01 00 01 01 01 01   ...$............
+| page 3 offset 8192
+|      0: 0a 00 00 00 03 00 00 00 00 00 00 00 00 00 00 00   ................
+|   4064: 00 00 00 00 00 00 00 00 00 00 00 00 06 04 01 0c   ................
+|   4080: 01 03 02 06 04 01 0c 01 02 02 05 04 09 0c 01 02   ................
+| page 4 offset 12288
+|      0: 0d 00 00 00 03 0f be 00 0f ea 0f d4 0f be 00 00   ................
+|   4016: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 14 03   ................
+|   4032: 05 00 17 17 17 61 20 62 20 63 67 20 68 20 69 67   .....a b cg h ig
+|   4048: 20 68 20 69 14 02 05 00 17 17 17 67 20 68 20 69    h i.......g h i
+|   4064: 61 20 62 20 63 67 20 68 20 69 14 01 05 00 17 17   a b cg h i......
+|   4080: 17 61 20 62 20 63 64 20 65 20 66 67 20 68 20 69   .a b cd e fg h i
+| page 5 offset 16384
+|      0: 0d 00 00 00 03 0f e8 00 0f f8 0f f0 0f e8 00 00   ................
+|   4064: 00 00 00 00 00 00 00 00 06 03 03 00 12 03 00 03   ................
+|   4080: 06 02 03 00 12 03 00 03 06 01 03 00 12 03 00 03   ................
+| page 6 offset 20480
+|      0: 0a 00 00 00 01 0f f4 00 0f f4 00 00 01 00 00 00   ................
+|   4080: 00 00 00 00 0b 03 1b 01 76 65 72 73 69 6f 6e 04   ........version.
+| page 7 offset 24576
+|      0: 0d 00 00 00 03 0f 9e 00 0f e6 0f ef 00 00 00 00   ................
+|   3984: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 41 84   ..............A.
+|   4000: 80 80 80 80 01 04 00 81 06 00 00 00 34 02 30 61   ............4.0a
+|   4016: 01 01 01 01 01 62 01 01 01 01 01 63 01 01 01 01   .....b.....c....
+|   4032: 01 64 01 01 01 65 01 01 01 66 01 01 01 67 01 01   .d...e...f...g..
+|   4048: 01 01 01 68 01 01 01 01 01 69 01 01 01 04 06 06   ...h.....i......
+|   4064: 06 04 04 04 06 06 07 01 03 00 14 03 09 09 09 0f   ................
+|   4080: 0a 03 00 24 00 00 00 00 01 01 01 00 01 01 01 01   ...$............
+| page 8 offset 28672
+|      0: 0a 00 00 00 01 0f fa 00 00 00 00 00 00 00 00 00   ................
+|   4080: 00 00 00 00 00 00 00 00 00 00 05 04 09 0c 01 12   ................
+| page 9 offset 32768
+|      0: 0d 00 00 00 03 0f be 00 0f ea 0f d4 0f be 00 00   ................
+|   4016: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 14 03   ................
+|   4032: 05 00 17 17 17 61 20 62 20 63 67 20 68 20 69 67   .....a b cg h ig
+|   4048: 20 68 20 69 14 02 05 00 17 17 17 67 20 68 20 69    h i.......g h i
+|   4064: 61 20 62 20 63 67 20 68 20 69 14 01 05 00 17 17   a b cg h i......
+|   4080: 17 61 20 62 20 63 64 20 65 20 66 67 20 68 20 69   .a b cd e fg h i
+| page 10 offset 36864
+|      0: 0a 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00   ................
+|   4080: 00 00 00 00 0b 03 1b 01 76 65 72 73 00 00 00 00   ........vers....
+| end crash-f928a9c1ec68dd.db
+}]} {}
+
+do_catchsql_test 80.1 {
+SELECT snippet(rowid, -1, '.', '..', '[', '(]'),snippet(rowid, -1, '.', '.', '', '(]'), highlight(t1, 29, 1 , '') FROM t1('g+ h') WHERE rank MATCH 'bm25(1.0, 10)' ORDER BY NOT (SELECT 1 FROM t1('g+ æ') WHERE rank MATCH 'bm25(1.0, 10)' ORDER BY rank);
+} {1 {database disk image is malformed}}
+
+
 sqlite3_fts5_may_be_corrupt 0
 finish_test

@@ -452,6 +452,346 @@ do_catchsql_test 2.1 {
 SELECT * FROM t1('R*R*R*R*') WHERE (a,b)<=(current_date,0) ORDER BY rowid DESC;
 } {1 {database disk image is malformed}}

+#-------------------------------------------------------------------------
+reset_db
+do_test 3.0 {
+  sqlite3 db {}
+  db deserialize [decode_hexdb {
+.open --hexdb
+| size 32768 pagesize 4096 filename crash-c69fcaceff1e50.db
+| page 1 offset 0
+|      0: 53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00   SQLite format 3.
+|     16: 10 00 01 01 00 40 20 20 00 00 00 00 00 00 00 08   .....@  ........
+|     32: 00 00 00 02 00 00 00 01 00 00 00 09 00 00 00 04   ................
+|     96: 00 00 00 00 0d 0f c7 00 07 0d 92 00 0f 8d 0f 36   ...............6
+|    112: 0e cb 0e 6b 0e 0e 0d b6 0d 92 0d 92 00 00 00 00   ...k............
+|   3472: 00 00 22 08 06 17 11 11 01 31 74 61 62 6c 65 74   .........1tablet
+|   3488: 32 74 32 08 43 52 45 41 54 45 20 54 41 42 4c 45   2t2.CREATE TABLE
+|   3504: 20 74 32 28 78 29 56 07 06 17 1f 1f 01 7d 74 61    t2(x)V.......ta
+|   3520: 62 6c 65 74 31 5f 63 6f 6e 66 69 67 74 31 5f 63   blet1_configt1_c
+|   3536: 6f 6e 66 69 67 07 43 52 45 41 54 45 20 54 41 42   onfig.CREATE TAB
+|   3552: 4c 45 20 27 74 31 5f 63 6f 6e 66 69 67 27 28 6b   LE 't1_config'(k
+|   3568: 20 50 52 49 4d 41 52 59 20 4b 45 59 2c 20 76 29    PRIMARY KEY, v)
+|   3584: 20 57 49 54 48 4f 55 54 20 52 4f 57 49 44 5b 06    WITHOUT ROWID[.
+|   3600: 07 17 21 21 01 81 01 74 61 62 6c 65 74 31 5f 64   ..!!...tablet1_d
+|   3616: 6f 63 73 69 7a 65 74 31 5f 64 6f 63 73 69 7a 65   ocsizet1_docsize
+|   3632: 06 43 52 45 41 54 45 20 54 41 42 4c 45 20 27 74   .CREATE TABLE 't
+|   3648: 31 5f 64 6f 63 73 69 7a 65 27 28 69 64 20 49 4e   1_docsize'(id IN
+|   3664: 54 45 47 45 52 20 50 52 49 4d 41 52 59 20 4b 45   TEGER PRIMARY KE
+|   3680: 59 2c 20 73 7a 20 42 4c 4f 42 29 5e 05 07 17 21   Y, sz BLOB)^...!
+|   3696: 21 01 81 07 74 61 62 6c 65 74 31 5f 63 6f 6e 74   !...tablet1_cont
+|   3712: 65 6e 74 74 31 5f 63 6f 6e 74 65 6e 74 05 43 52   entt1_content.CR
+|   3728: 45 41 54 45 20 54 41 42 4c 45 20 27 74 31 5f 63   EATE TABLE 't1_c
+|   3744: 6f 6e 74 65 6e 74 27 28 69 64 20 49 4e 54 45 47   ontent'(id INTEG
+|   3760: 45 52 20 50 52 49 4d 41 52 59 20 4b 45 59 2c 20   ER PRIMARY KEY, 
+|   3776: 63 30 2c 20 63 31 2c 20 63 32 29 69 04 07 17 19   c0, c1, c2)i....
+|   3792: 19 01 81 2d 74 61 62 6c 65 74 31 5f 69 64 78 74   ...-tablet1_idxt
+|   3808: 31 5f 69 64 78 04 43 52 45 41 54 45 20 54 41 42   1_idx.CREATE TAB
+|   3824: 4c 45 20 27 74 31 5f 69 64 78 27 28 73 65 67 69   LE 't1_idx'(segi
+|   3840: 64 2c 20 74 65 72 6d 2c 20 70 67 6e 6f 2c 20 50   d, term, pgno, P
+|   3856: 52 49 4d 41 52 59 20 4b 45 59 28 73 65 67 69 64   RIMARY KEY(segid
+|   3872: 2c 20 74 65 72 6d 29 29 20 57 49 54 48 4f 55 54   , term)) WITHOUT
+|   3888: 20 52 4f 57 49 44 55 03 07 17 1b 1b 01 81 01 74    ROWIDU........t
+|   3904: 61 62 6c 65 74 31 5f 64 61 74 61 74 31 5f 64 61   ablet1_datat1_da
+|   3920: 74 61 03 43 52 45 41 54 45 20 54 41 42 4c 45 20   ta.CREATE TABLE 
+|   3936: 27 74 31 5f 64 61 74 61 27 28 69 64 20 49 4e 54   't1_data'(id INT
+|   3952: 45 47 45 52 20 50 52 49 4d 41 52 59 20 4b 45 59   EGER PRIMARY KEY
+|   3968: 2c 20 62 6c 6f 63 6b 20 42 4c 4f 42 29 38 02 06   , block BLOB)8..
+|   3984: 17 11 11 08 5f 74 61 62 6c 65 74 31 74 31 43 52   ...._tablet1t1CR
+|   4000: 45 41 54 45 20 56 49 52 54 55 41 4c 20 54 41 42   EATE VIRTUAL TAB
+|   4016: 4c 45 20 74 31 20 55 53 49 4e 47 20 66 74 73 35   LE t1 USING fts5
+|   4032: 28 61 2c 62 2c 63 29 00 00 00 00 00 00 00 00 00   (a,b,c).........
+| page 3 offset 8192
+|      0: 0d 00 00 00 03 0c 94 00 0f e6 0f ef 0c 94 00 00   ................
+|   3216: 00 00 00 00 86 4a 84 80 80 80 80 01 04 00 8d 18   .....J..........
+|   3232: 00 00 01 bb 02 30 30 01 02 06 01 02 06 01 02 06   .....00.........
+|   3248: 1f 02 03 01 02 03 01 02 03 01 08 32 30 31 36 30   ...........20160
+|   3264: 36 30 39 01 02 07 01 02 07 01 02 07 01 01 34 01   609...........4.
+|   3280: 02 05 01 02 05 01 02 05 01 01 35 01 02 04 01 02   ..........5.....
+|   3296: 04 01 02 04 02 07 30 30 30 30 30 30 30 1c 02 04   ......0000000...
+|   3312: 01 02 04 01 02 04 01 06 62 69 6e 61 72 79 03 06   ........binary..
+|   3328: 01 02 02 03 06 01 02 02 03 06 01 02 02 03 06 01   ................
+|   3344: 02 02 03 06 01 02 02 03 06 01 02 02 03 06 01 02   ................
+|   3360: 02 03 06 01 02 02 03 06 01 02 02 03 06 01 02 02   ................
+|   3376: 03 06 01 02 02 03 06 01 02 02 01 08 63 6f 6d 70   ............comp
+|   3392: 69 6c 65 72 01 02 02 01 02 02 01 02 02 01 06 64   iler...........d
+|   3408: 62 73 74 61 74 07 02 03 01 02 03 01 02 03 02 04   bstat...........
+|   3424: 65 62 75 67 04 02 02 01 02 02 01 02 02 01 06 65   ebug...........e
+|   3440: 6b b1 62 6c 65 07 02 02 01 02 02 01 02 02 01 02   k.ble...........
+|   3456: 02 01 02 02 01 02 02 01 02 02 01 02 02 01 02 02   ................
+|   3472: 01 02 02 01 02 02 05 02 02 01 02 02 01 02 02 01   ................
+|   3488: 02 02 01 02 02 01 02 02 01 02 02 01 02 02 01 02   ................
+|   3504: 02 01 02 02 02 08 78 74 65 6e 73 69 6f 6e 1f 02   ......xtension..
+|   3520: 04 01 02 04 01 02 04 01 04 66 74 73 34 1a 02 03   .........fts4...
+|   3536: 01 02 03 01 02 03 04 01 35 0d 02 03 01 02 03 01   ........5.......
+|   3552: 02 03 01 03 67 63 63 01 02 03 01 02 03 01 02 03   ....gcc.........
+|   3568: 02 06 65 6f 70 6f 6c 79 10 02 03 01 02 03 01 02   ..eopoly........
+|   3584: 03 01 05 6a 73 6f 6e 31 13 02 03 01 02 03 01 02   ...json1........
+|   3600: 03 01 04 6c 6f 61 64 1f 02 03 01 02 03 01 02 03   ...load.........
+|   3616: 01 03 6d 61 78 1c 02 02 01 02 02 01 02 02 02 05   ..max...........
+|   3632: 65 6d 6f 72 79 1c 02 03 01 02 03 01 02 03 04 04   emory...........
+|   3648: 73 79 73 35 16 02 03 01 02 03 01 02 03 01 06 6e   sys5...........n
+|   3664: 6f 63 61 73 65 02 06 01 02 02 03 06 01 02 02 03   ocase...........
+|   3680: 06 01 02 02 03 06 01 02 02 03 06 01 02 02 03 06   ................
+|   3696: 01 02 02 03 06 01 02 02 03 06 01 02 02 03 06 01   ................
+|   3712: 02 02 03 06 01 02 02 03 06 01 02 02 03 06 01 02   ................
+|   3728: 02 01 04 6f 6d 69 74 1f 02 02 01 02 02 01 02 01   ...omit.........
+|   3744: ff ff ff ff ff ff ff ff ff ff ff ff ff ff f1 02   ................
+|   3760: 58 81 96 4d 01 06 01 02 02 03 06 01 02 02 03 06   X..M............
+|   3776: 01 02 02 03 06 01 02 02 03 06 01 02 02 03 06 01   ................
+|   3792: 02 02 03 06 01 02 02 03 06 01 02 02 03 06 01 02   ................
+|   3808: 02 03 06 01 02 02 03 06 01 02 02 03 06 01 02 02   ................
+|   3824: 01 0a 74 68 72 65 61 64 73 61 66 65 22 02 02 01   ..threadsafe....
+|   3840: 02 02 01 02 02 01 04 76 74 61 62 07 02 04 01 02   .......vtab.....
+|   3856: 04 01 02 04 01 01 78 01 06 01 01 02 01 06 01 01   ......x.........
+|   3872: 02 01 06 01 c6 02 01 06 01 01 02 01 06 01 01 02   ................
+|   3888: 01 06 01 01 02 01 06 01 01 02 01 06 01 01 02 01   ................
+|   3904: 06 01 01 02 00 f6 01 01 02 01 06 01 01 02 01 06   ................
+|   3920: 01 01 02 01 06 01 01 02 01 06 01 01 02 01 06 01   ................
+|   3936: 01 02 01 06 01 01 02 01 06 01 01 02 01 06 01 01   ................
+|   3952: 02 01 06 01 01 02 01 06 01 01 02 01 06 01 01 02   ................
+|   3968: 01 06 01 01 02 01 06 01 01 02 01 06 01 01 02 01   ................
+|   3984: 06 01 01 02 01 06 01 01 02 01 06 01 01 02 01 06   ................
+|   4000: 01 01 02 01 06 01 01 02 01 06 01 01 02 01 06 01   ................
+|   4016: 01 02 01 06 01 01 02 01 06 01 01 02 01 06 01 01   ................
+|   4032: 02 01 06 01 01 02 01 06 01 01 02 04 15 13 0c 0c   ................
+|   4048: 12 44 13 11 0f 47 13 0f 0c 0e 11 10 0f 0e 10 0f   .D...G..........
+|   4064: 44 0f 10 40 15 0f 07 01 03 00 14 24 5a 24 24 0f   D..@.......$Z$$.
+|   4080: 0a 03 00 24 00 00 00 00 01 01 01 00 01 01 01 01   ...$............
+| page 4 offset 12288
+|      0: 0a 00 00 00 01 0f fa 00 0f fa 00 00 00 00 00 00   ................
+|   4080: 00 00 00 00 00 00 00 00 00 00 05 04 09 0c 01 02   ................
+| page 7 offset 24576
+|      0: 0a 00 00 00 01 0f f4 00 0f f4 00 00 00 00 00 00   ................
+|   4080: 00 00 00 00 0b 03 1b 01 76 65 72 73 69 6f 6e 04   ........version.
+| end crash-c69fcaceff1e50.db
+}]} {}
+
+do_catchsql_test 3.1 {
+  UPDATE t1 SET b=quote(zeroblob(200)) WHERE a MATCH 'thra*T';
+} {1 {database disk image is malformed}}
+
+#-------------------------------------------------------------------------
+reset_db
+do_test 4.0 {
+  sqlite3 db {}
+  db deserialize [decode_hexdb {
+.open --hexdb
+| size 24576 pagesize 4096 filename crash-ef6738247b1344.db
+| page 1 offset 0
+|      0: 53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00   SQLite format 3.
+|     16: 10 00 01 01 00 40 20 20 00 10 00 06 40 00 00 06   .....@  ....@...
+|     32: 00 00 00 00 00 00 00 00 00 00 00 06 00 00 00 00   ................
+|     96: 00 00 00 00 0d 00 00 00 06 0e 0f 00 0f aa 0f 53   ...............S
+|    112: 0e e8 0e 8b 0e 33 0e 0f 00 00 00 00 00 00 00 00   .....3..........
+|   3584: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 22   ................
+|   3600: 06 06 17 11 11 01 31 74 61 62 6c 65 62 62 62 62   ......1tablebbbb
+|   3616: 06 43 52 45 41 54 45 20 54 41 42 4c 45 20 62 62   .CREATE TABLE bb
+|   3632: 28 61 29 56 05 06 17 1f 1f 01 7d 74 61 62 6c 65   (a)V.......table
+|   3648: 74 31 5f 63 6f 6e 66 69 67 74 31 5f 63 6f 6e 66   t1_configt1_conf
+|   3664: 69 67 05 43 52 45 41 54 45 20 54 41 42 4c 45 20   ig.CREATE TABLE 
+|   3680: 27 74 31 5f 63 6f 6e 66 69 67 27 28 6b 20 50 52   't1_config'(k PR
+|   3696: 49 4d 41 52 59 20 4b 45 59 2c 20 76 29 20 57 49   IMARY KEY, v) WI
+|   3712: 54 48 4f 55 54 20 52 4f 57 49 44 5b 04 07 17 21   THOUT ROWID[...!
+|   3728: 21 01 81 01 74 61 62 6c 65 74 31 5f 64 6f 63 73   !...tablet1_docs
+|   3744: 69 7a 65 74 31 5f 64 6f 63 73 69 7a 65 04 43 52   izet1_docsize.CR
+|   3760: 45 41 54 45 20 54 41 42 4c 45 20 27 74 31 5f 64   EATE TABLE 't1_d
+|   3776: 6f 63 73 69 7a 65 27 28 69 64 20 49 4e 54 45 47   ocsize'(id INTEG
+|   3792: 45 52 20 50 52 49 4d 41 52 59 20 4b 45 59 2c 20   ER PRIMARY KEY, 
+|   3808: 73 7a 20 42 4c 4f 42 29 69 03 07 17 19 19 01 81   sz BLOB)i.......
+|   3824: 2d 74 61 62 6c 65 74 31 5f 69 64 78 74 31 5f 69   -tablet1_idxt1_i
+|   3840: 64 78 03 43 52 45 41 54 45 20 54 41 42 4c 45 20   dx.CREATE TABLE 
+|   3856: 27 74 31 5f 69 64 78 27 28 73 65 67 69 64 2c 20   't1_idx'(segid, 
+|   3872: 74 65 72 6d 2c 20 6f 67 6e 6f 2c 20 50 52 49 4d   term, ogno, PRIM
+|   3888: 41 52 59 20 4b 45 59 28 73 65 67 69 64 2c 20 74   ARY KEY(segid, t
+|   3904: 65 72 6d 29 29 20 57 49 54 48 4f 55 54 20 52 4f   erm)) WITHOUT RO
+|   3920: 57 49 44 55 35 07 17 1b 1b 01 81 01 74 61 62 6c   WIDU5.......tabl
+|   3936: 65 74 31 5f 64 61 74 61 74 31 5f 64 61 74 61 02   et1_datat1_data.
+|   3952: 43 52 45 41 54 45 20 54 41 42 4c 45 20 27 74 31   CREATE TABLE 't1
+|   3968: 5f 64 61 74 61 27 28 69 64 20 49 4e 54 45 47 45   _data'(id INTEGE
+|   3984: 52 20 50 52 49 4d 41 52 59 20 4b 45 59 2c 20 62   R PRIMARY KEY, b
+|   4000: 6c 6f 63 6b 20 42 4c 4f 42 29 54 01 07 17 11 11   lock BLOB)T.....
+|   4016: 08 81 15 74 61 62 6c 65 74 31 74 31 43 52 45 41   ...tablet1t1CREA
+|   4032: 54 45 20 56 49 52 54 55 41 4c 20 54 41 42 4c 45   TE VIRTUAL TABLE
+|   4048: 20 74 31 20 55 53 49 4e 47 20 66 74 73 35 28 61    t1 USING fts5(a
+|   4064: 2c 62 2c 70 72 65 66 69 78 3d 22 31 2c 32 2c 33   ,b,prefix=.1,2,3
+|   4080: 2c 34 22 2c 20 63 6f 6e 74 65 6e 74 3d 22 22 29   ,4., content=..)
+| page 2 offset 4096
+|      0: 0d 0b 6a 00 37 09 4c 02 0f e7 09 4c 0f c6 0f a4   ..j.7.L....L....
+|     16: 0f 88 0f 6d 0f 4b 0f 2c 0f 0e 0e ec 0e cd 0e ad   ...m.K.,........
+|     32: 0e 8e 0e 6c 0e 4b 0e 29 0e 08 0d e6 0d c4 0d b5   ...l.K.)........
+|     48: 0d 97 0d 76 0d 54 0d 31 0d 15 0c f3 0c d3 0c b5   ...v.T.1........
+|     64: 0c 95 0c 73 0c 54 0c 32 0c 10 0b ee 0b cc 0b b0   ...s.T.2........
+|     80: 0b 8d 0b 7e 0b 48 0b 2e 0b 0b 0a ef 0a cc 0a 00   ...~.H..........
+|   2368: 00 00 00 00 00 00 00 00 00 00 00 00 15 0a 03 00   ................
+|   2384: 30 00 00 00 01 01 03 35 00 03 01 01 12 02 01 12   0......5........
+|   2400: 03 01 11 1c 8c 80 80 80 80 10 02 9c 3e 00 00 00   ............>...
+|   2416: 17 01 05 05 34 74 61 62 6c 03 02 03 01 04 77 68   ....4tabl.....wh
+|   2432: 65 72 03 02 06 09 1b 8c 80 80 80 80 0f 03 00 3c   er.............<
+|   2448: 00 00 00 16 05 34 66 74 73 34 03 02 02 01 04 6e   .....4fts4.....n
+|   2464: 75 6d 62 03 06 01 04 09 1b 8c 80 80 80 80 0e 03   umb.............
+|   2480: 00 3c 00 00 00 16 04 33 74 68 65 03 06 01 01 04   .<.....3the.....
+|   2496: 01 03 77 68 65 03 02 04 04 0a 1b 8c 80 80 80 80   ..whe...........
+|   2512: 0d 03 00 3c 00 00 00 16 04 33 6e 75 6d 03 06 01   ...<.....3num...
+|   2528: 01 05 01 03 74 61 62 03 02 03 04 0a 19 8c 80 80   ....tab.........
+|   2544: 80 80 0c 03 00 38 00 00 00 14 03 32 77 68 03 02   .....8.....2wh..
+|   2560: 04 00 04 33 66 74 73 03 12 02 04 07 18 8c 80 80   ...3fts.........
+|   2576: 80 80 0b 03 00 36 00 00 00 13 03 32 74 61 03 02   .....6.....2ta..
+|   2592: 03 02 01 68 03 06 01 01 04 04 07 1b 8c 80 80 80   ...h............
+|   2608: 80 0a 03 00 3c 00 00 00 16 03 32 6e 75 03 06 01   ....<.....2nu...
+|   2624: 01 05 01 02 6f 66 03 06 01 01 06 04 09 19 8c 80   ....of..........
+|   2640: 82 d0 80 09 03 00 38 00 00 00 14 03 32 66 74 03   ......8.....2ft.
+|   2656: 02 02 01 02 69 73 03 06 01 01 03 04 07 18 8c 80   ....is..........
+|   2672: 80 80 80 08 03 00 36 00 00 00 13 02 31 74 03 08   ......6.....1t..
+|   2688: 03 01 01 04 01 01 77 03 02 04 04 09 1a 8c 80 80   ......w.........
+|   2704: 80 80 07 03 00 3a 00 00 00 15 02 31 6e 03 08 01   .....:.....1n...
+|   2720: 01 02 05 01 01 6f 03 06 01 01 06 04 09 18 8c 80   .....o..........
+|   2736: 81 80 80 06 03 00 36 00 00 00 13 04 12 31 66 03   ......6......1f.
+|   2752: 02 02 01 01 69 03 06 01 01 03 05 06 1c 8c 80 80   ....i...........
+|   2768: 80 80 05 03 00 3e 00 00 00 17 04 30 74 68 65 03   .....>.....0the.
+|   2784: 06 01 01 04 01 05 77 68 65 72 65 03 02 04 0a 15   ......where.....
+|   2800: 8c 80 65 80 80 04 03 00 30 00 00 00 11 01 01 06   ..e.....0.......
+|   2816: 06 30 74 61 62 6c 65 03 02 03 07 1c 8c 80 80 80   .0table.........
+|   2832: 80 03 03 00 3e 00 00 00 17 07 30 6e 75 6d 62 65   ....>.....0numbe
+|   2848: 72 03 06 01 01 05 01 02 6f 66 03 06 04 0d 13 8c   r.......of......
+|   2864: 80 80 80 80 02 03 00 2c 00 00 00 0f fc 01 03 02   .......,........
+|   2880: 30 6e 03 06 01 00 f2 07 1b 8c 80 80 80 80 01 03   0n..............
+|   2896: 00 3c 00 00 00 16 08 30 66 74 73 34 61 75 78 03   .<.....0fts4aux.
+|   2912: 03 02 01 02 69 73 03 06 04 0c 00 00 00 18 ea 00   ....is..........
+|   2928: 00 00 01 01 02 24 00 02 01 01 12 02 01 12 08 88   .....$..........
+|   2944: 80 80 80 80 12 03 00 12 10 00 00 05 02 1c 88 80   ................
+|   2960: 80 80 80 11 03 00 3e 00 00 00 17 05 34 72 6f 77   ......>.....4row
+|   2976: 73 02 06 01 01 05 01 04 74 68 65 72 02 02 04 0b   s.......ther....
+|   2992: 15 88 80 80 80 80 10 03 00 2f ff ff f0 11 02 01   ........./......
+|   3008: 01 07 05 34 62 65 74 77 02 02 04 08 1b 88 80 80   ...4betw........
+|   3024: 80 80 0f cf 00 3c 00 00 00 16 04 04 33 72 6f 77   .....<......3row
+|   3040: 02 06 01 01 05 01 03 74 68 65 02 08 05 0a 1b 88   .......the......
+|   3056: 80 80 80 80 0d 03 00 3c 00 00 00 16 00 01 02 04   .......<........
+|   3072: 33 61 72 65 02 02 03 01 03 62 65 74 02 02 07 08   3are.....bet....
+|   3088: 1b 88 80 80 80 80 0d 03 00 3c 00 00 00 16 03 32   .........<.....2
+|   3104: 74 68 02 08 02 01 01 07 00 04 33 61 6e 64 02 06   th........3and..
+|   3120: 04 0a 1b 88 80 80 80 80 0c 03 00 3c 00 00 00 16   ...........<....
+|   3136: 03 32 69 6e 02 06 01 01 06 01 02 72 6f 02 06 01   .2in.......ro...
+|   3152: 01 05 04 09 18 88 80 80 80 80 0b 03 00 36 00 00   .............6..
+|   3168: 00 13 02 03 32 61 72 02 02 03 01 02 62 65 02 02   ....2ar.....be..
+|   3184: 04 05 07 1b 88 80 80 80 80 0a 03 00 3c 00 00 00   ............<...
+|   3200: 16 12 31 74 02 08 02 01 01 07 00 03 32 61 6e 02   ..1t........2an.
+|   3216: 06 01 01 04 09 19 88 80 80 80 80 09 03 00 38 00   ..............8.
+|   3232: 00 00 14 02 31 6e 02 06 01 01 03 01 01 72 02 06   ....1n.......r..
+|   3248: 01 01 05 04 08 17 78 80 80 80 80 08 03 00 34 10   ......x.......4.
+|   3264: 01 00 12 02 31 62 02 02 04 01 01 69 02 06 01 01   ....1b.....i....
+|   3280: 06 04 06 19 88 80 80 80 80 07 03 00 38 00 00 00   ............8...
+|   3296: 14 04 02 31 32 02 02 05 01 01 61 02 08 03 01 01   ...12.....a.....
+|   3312: 02 05 06 1b 88 80 80 80 80 06 03 00 3c 00 00 00   ............<...
+|   3328: 16 06 30 74 68 65 72 65 e7 02 02 00 02 31 31 02   ..0there.....11.
+|   3344: 06 01 01 04 0a 15 88 80 80 80 80 05 03 00 30 00   ..............0.
+|   3360: 00 00 11 01 01 05 e5 30 74 68 65 02 06 01 01 07   .......0the.....
+|   3376: 07 1c 88 80 80 80 80 04 03 00 3e 00 00 00 17 01   ..........>.....
+|   3392: 01 06 02 30 6e 02 06 01 01 03 01 04 72 6f 77 73   ...0n.......rows
+|   3408: 02 06 07 08 1b 88 80 80 80 80 03 03 00 3c 00 00   .............<..
+|   3424: 00 16 08 30 62 65 74 77 65 65 6e 02 02 04 01 02   ...0between.....
+|   3440: 69 6e 02 06 04 0c 1a 88 80 80 80 80 02 03 00 3a   in.............:
+|   3456: 00 00 00 15 04 30 61 6e 64 02 06 01 01 02 02 02   .....0and.......
+|   3472: 72 65 02 02 03 04 0a 17 88 80 80 80 80 01 03 00   re..............
+|   3488: 34 01 00 00 12 02 30 31 02 06 01 01 04 01 01 32   4.....01.......2
+|   3504: 02 02 05 04 08 08 84 80 80 80 80 12 03 00 16 00   ................
+|   3520: 00 00 05 04 1b 84 80 80 80 80 11 03 00 3c 00 00   .............<..
+|   3536: 00 16 05 34 74 61 62 6c 01 06 01 01 05 02 03 65   ...4tabl.......e
+|   3552: 72 6d 01 02 04 0b 1b 84 80 80 80 80 10 03 00 3c   rm.............<
+|   3568: 00 00 00 16 05 34 65 61 63 68 01 02 02 01 04 70   .....4each.....p
+|   3584: 72 65 73 01 02 05 04 09 1a 84 80 80 80 80 0f 03   res.............
+|   3600: 00 3a 00 00 00 15 04 33 74 65 72 01 02 04 02 02   .:.....3ter.....
+|   3616: 68 65 01 06 01 01 03 04 08 1b 84 80 80 80 80 0e   he..............
+|   3632: 03 00 3c 00 00 00 16 04 33 70 72 65 01 02 05 01   ..<.....3pre....
+|   3648: 03 74 61 62 01 06 01 01 05 04 08 1a 84 80 80 80   .tab............
+|   3664: 80 0d 03 0d 1a 00 00 00 15 04 33 66 6e 72 01 02   ..........3fnr..
+|   3680: 02 02 02 74 73 01 06 01 01 04 04 08 1b 84 80 80   ...ts...........
+|   3696: 80 80 0c 03 00 3c 00 00 00 16 03 32 74 68 01 06   .....<.....2th..
+|   3712: 01 01 03 00 04 33 65 61 63 01 02 03 04 09 18 84   .....3eac.......
+|   3728: 80 80 80 80 0b 03 00 36 00 00 00 13 03 32 74 61   .......6.....2ta
+|   3744: 01 06 01 01 05 02 01 65 01 02 04 04 09 19 84 80   .......e........
+|   3760: 80 80 80 0a 03 00 38 00 00 00 14 03 30 c9 6e 01   ......8.....0.n.
+|   3776: 06 01 01 02 01 02 70 72 01 02 05 04 09 18 84 80   ......pr........
+|   3792: 80 80 80 09 03 00 36 00 00 00 13 03 32 66 6f 01   ......6.....2fo.
+|   3808: 02 0b e2 01 74 01 06 01 01 04 04 07 1b 84 80 80   ....t...........
+|   3824: 86 f0 08 03 00 3c 00 00 00 16 02 31 74 01 0a 04   .....<.....1t...
+|   3840: 01 01 03 04 00 03 32 65 61 01 02 03 04 0a 17 84   ......2ea.......
+|   3856: 80 80 80 80 07 03 00 34 00 00 00 12 02 31 69 01   .......4.....1i.
+|   3872: 06 01 01 02 01 01 70 01 02 05 04 08 18 84 80 80   ......p.........
+|   3888: 80 80 06 03 00 36 00 00 00 13 02 31 65 01 02 03   .....6.....1e...
+|   3904: 01 01 66 01 08 02 01 01 04 04 06 1b 84 80 80 80   ..f.............
+|   3920: 80 05 03 00 3c 00 00 00 16 05 30 74 65 72 6d 01   ....<.....0term.
+|   3936: 02 04 02 02 68 65 01 06 01 01 03 04 09 14 84 80   ....he..........
+|   3952: 80 80 80 04 03 00 2e 00 00 00 10 06 30 74 61 62   ............0tab
+|   3968: 6c 65 01 06 01 01 05 04 15 84 7f 80 80 80 03 03   le..............
+|   3984: 00 30 00 00 00 11 02 08 30 70 72 65 73 65 6e 74   .0......0present
+|   4000: 01 02 05 05 1b 84 80 22 80 80 02 03 00 3c 00 00   .............<..
+|   4016: 00 16 04 30 66 74 73 01 06 01 01 04 01 02 69 6e   ...0fts.......in
+|   4032: 01 06 01 01 04 0a 1a 84 80 80 80 80 01 03 00 3a   ...............:
+|   4048: 00 00 00 15 05 30 65 61 63 68 01 02 03 01 03 66   .....0each.....f
+|   4064: 6f 72 01 02 02 04 09 06 01 03 00 12 03 0b 0f 00   or..............
+|   4080: 00 08 8c 80 80 80 80 11 03 00 16 00 00 00 05 04   ................
+| page 3 offset 8192
+|      0: 0a 00 00 00 32 0e 4f 00 0f fa 0f f1 0f e9 0f e1   ....2.O.........
+|     16: 0f d8 0f d1 0f c9 0f c1 0f b9 0f b1 0f a9 0f a0   ................
+|     32: 0f 98 0f 90 0f 87 0f 80 0f 78 0f 71 0f 68 0f 5f   .........x.q.h._
+|     48: 0f 56 0f 00 00 00 00 00 00 00 00 00 00 00 00 00   .V..............
+|   3392: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08   ................
+|   3408: 04 01 10 01 03 34 74 20 07 04 01 0e 01 03 34 1e   .....4t ......4.
+|   3424: 09 04 01 12 01 03 33 74 68 1c 08 04 01 10 01 03   ......3th.......
+|   3440: 34 6e 1a 08 04 01 10 01 03 32 67 18 08 04 01 10   4n.......2g.....
+|   3456: 01 03 32 74 16 08 04 01 10 01 03 32 6e 14 07 04   ..2t.......2n...
+|   3472: 01 0e 01 03 32 12 08 04 01 10 01 03 31 74 10 08   ....2.......1t..
+|   3488: 04 01 10 01 03 31 6e 0e 07 04 01 0e 01 03 31 0c   .....1n.......1.
+|   3504: 09 04 01 12 01 03 30 74 68 0a 08 04 01 10 01 03   ......0th.......
+|   3520: 30 74 08 09 04 01 12 01 03 30 6e 75 06 08 04 01   0t.......0nu....
+|   3536: 10 01 03 30 6e 04 06 04 01 0c 01 03 02 08 04 01   ...0n...........
+|   3552: 10 01 02 34 72 22 07 04 01 0e 01 02 34 20 08 04   ...4r.......4 ..
+|   3568: 01 10 01 02 33 72 1e 09 04 01 12 01 02 33 61 72   ....3r.......3ar
+|   3584: 1c 18 04 01 10 01 02 32 74 1a 08 04 01 10 01 02   .......2t.......
+|   3600: 32 69 18 09 04 01 12 01 02 32 61 72 16 08 04 01   2i.......2ar....
+|   3616: 10 01 02 31 74 2a 08 04 01 0f 01 02 31 6e 12 0a   ...1t*......1n..
+|   3632: d4 01 10 01 02 31 62 10 08 04 01 10 01 02 31 32   .....1b.......12
+|   3648: 0e 0b 04 01 16 01 02 30 74 68 65 72 0c 08 04 01   .......0ther....
+|   3664: 10 01 02 30 74 0a 08 04 01 10 01 02 30 6e 08 08   ...0t.......0n..
+|   3680: 04 01 10 01 02 30 62 06 08 04 01 10 01 02 30 61   .....0b.......0a
+|   3696: 04 06 03 f1 0c 01 02 02 07 04 09 10 01 34 74 22   .............4t.
+|   3712: 06 04 09 0e 01 34 20 08 04 09 12 01 33 74 65 1e   .....4 .....3te.
+|   3728: 07 04 09 10 01 33 70 1c 07 04 09 10 01 33 66 1a   .....3p......3f.
+|   3744: 08 04 09 12 01 32 74 68 18 07 04 09 10 01 32 74   .....2th......2t
+|   3760: 16 07 04 09 10 01 32 69 14 07 04 09 10 01 32 66   ......2i......2f
+|   3776: 12 07 04 09 10 01 31 74 10 07 04 09 10 01 31 69   ......1t......1i
+|   3792: 0e 06 04 09 0e 01 31 0c 08 04 09 12 01 30 74 65   ......1......0te
+|   3808: 0a 07 04 09 10 01 30 74 08 07 04 09 10 01 30 70   ......0t......0p
+|   3824: 06 08 04 09 1e 61 30 66 74 04 05 00 00 00 00 00   .....a0ft.......
+| page 4 offset 12288
+|   4064: 00 00 00 00 00 00 00 00 00 00 00 05 03 03 00 10   ................
+|   4080: 03 05 05 02 03 00 10 04 06 05 01 03 00 10 04 04   ................
+| page 5 offset 16384
+|      0: 0a 00 00 00 02 0f eb 00 0f eb 0f f4 00 00 00 00   ................
+|   4064: 00 00 00 00 00 00 00 00 00 00 00 08 03 15 01 70   ...............p
+|   4080: 67 73 7a 18 0b 03 1b 01 76 65 72 73 69 6f 6e 04   gsz.....version.
+| end crash-ef6738247b1344.db
+}]} {}
+
+
+do_catchsql_test 4.1 {
+  BEGIN;
+  REPLACE INTO t1(rowid,b,a,rowid) VALUES(200,1,2,3);
+} {1 {database disk image is malformed}}
+
+do_catchsql_test 4.2 {
+  INSERT INTO t1(t1) VALUES('delete-all');
+} {1 {database disk image is malformed}}
+do_catchsql_test 4.3 {
+  REPLACE INTO t1(rowid,b,rowid,a) VALUES(200,1,2,3);
+} {1 {database disk image is malformed}}
+do_catchsql_test 4.4 {
+  REPLACE INTO t1(rowid,b,a,rowid) VALUES(0,1,2,3);
+} {1 {database disk image is malformed}}
+do_catchsql_test 4.5 {
+  REPLACE INTO t1(rowid,a,b,rowid) VALUES(200,1,2,3);
+} {1 {database disk image is malformed}}

 sqlite3_fts5_may_be_corrupt 0
 finish_test
@@ -0,0 +1,54 @@
+# 2015 Apr 24
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+# This file tests that FTS5 handles corrupt databases (i.e. internal
+# inconsistencies in the backing tables) correctly. In this case 
+# "correctly" means without crashing.
+#
+
+source [file join [file dirname [info script]] fts5_common.tcl]
+set testprefix fts5corrupt6
+
+# If SQLITE_ENABLE_FTS5 is defined, omit this file.
+ifcapable !fts5 {
+  finish_test
+  return
+}
+sqlite3_fts5_may_be_corrupt 1
+database_may_be_corrupt
+
+proc editblock {block} {
+  binary format Sa* 20000 [string range $block 2 end]
+}
+db func editblock editblock
+
+do_execsql_test 1.0 {
+  CREATE VIRTUAL TABLE ft USING fts5(abc, def);
+  WITH a(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM a WHERE i<1000
+  )
+  INSERT INTO ft SELECT 
+      'abc abc abc abc abc abc abc abc abc abc',
+      'def def def def def def def def def def'
+  FROM a;
+  UPDATE ft_data SET block = editblock(block) WHERE id=(
+    SELECT id FROM ft_data ORDER BY id LIMIT 1 OFFSET 5
+  );
+}
+
+do_catchsql_test 1.1 {
+  SELECT rowid FROM ft('def') ORDER BY rowid DESC LIMIT 1 OFFSET 9999;
+} {1 {database disk image is malformed}}
+
+
+sqlite3_fts5_may_be_corrupt 0
+finish_test
+
@@ -83,7 +83,7 @@ for {set i 0} {$i < 255} {incr i} {

 do_execsql_test 3.0 {
  CREATE VIRTUAL TABLE e1 USING fts5(text, tokenize = 'porter unicode61');
-  INSERT INTO e1 VALUES ("just a few words with a / inside");
+  INSERT INTO e1 VALUES ('just a few words with a / inside');
 }
 do_execsql_test 3.1 {
  SELECT rowid, bm25(e1) FROM e1 WHERE e1 MATCH '"just"' ORDER BY rank;
@@ -16,12 +16,16 @@ source [file join [file dirname [info script]] fts5_common.tcl]
 source $testdir/malloc_common.tcl
 set testprefix fts5fault4

-# If SQLITE_ENABLE_FTS3 is defined, omit this file.
+# If SQLITE_ENABLE_FTS5 is not defined, omit this file.
 ifcapable !fts5 {
  finish_test
  return
 }

+set ::TMPDBERROR [list 1 \
+  {unable to open a temporary database file for storing temporary tables}
+]
+
 #-------------------------------------------------------------------------
 # An OOM while dropping an fts5 table.
 #
@@ -391,7 +395,7 @@ do_faultsim_test 14.1 -faults oom-t* -prep {
 } -body {
  db eval { ALTER TABLE "tbl one" RENAME TO "tbl two" }
 } -test {
-  faultsim_test_result {0 {}}
+  faultsim_test_result {0 {}} $::TMPDBERROR
 }

 finish_test
@@ -188,11 +188,11 @@ foreach {tn pgsz} {
    INSERT INTO hh(hh, rank) VALUES('pgsz', $pgsz);

    WITH s(i) AS (SELECT 0 UNION ALL SELECT i+1 FROM s WHERE i<999)
-     INSERT INTO hh SELECT printf("%.3d%.3d%.3d %.3d%.3d%.3d",i,i,i,i+1,i+1,i+1)
+     INSERT INTO hh SELECT printf('%.3d%.3d%.3d %.3d%.3d%.3d',i,i,i,i+1,i+1,i+1)
     FROM s;

    WITH s(i) AS (SELECT 0 UNION ALL SELECT i+1 FROM s WHERE i<999)
-     INSERT INTO hh SELECT printf("%.3d%.3d%.3d %.3d%.3d%.3d",i,i,i,i+1,i+1,i+1)
+     INSERT INTO hh SELECT printf('%.3d%.3d%.3d %.3d%.3d%.3d',i,i,i,i+1,i+1,i+1)
     FROM s;

    INSERT INTO hh(hh) VALUES('optimize');
@@ -153,18 +153,12 @@ SQLite. Documentation follows.
    the ICU extension LIKE operator is 50000, defined in source 
    file "icu.c".

-  3.3 Collation Sequence Security Issue
+  3.3 Collation Sequence Security

    Internally, SQLite assumes that indices stored in database files
    are sorted according to the collation sequence indicated by the
    SQL schema. Changing the definition of a collation sequence after
    an index has been built is therefore equivalent to database
-    corruption. The SQLite library is not very well tested under
-    these conditions, and may contain potential buffer overruns
-    or other programming errors that could be exploited by a malicious
-    programmer.
-
-    If the ICU extension is used in an environment where potentially
-    malicious users may execute arbitrary SQL (i.e. gears), they
-    should be prevented from invoking the icu_load_collation() function,
-    possibly using the authorisation callback.
+    corruption. The SQLite library is well tested for robustness in
+    the fact of database corruption.  Database corruption may well
+    lead to incorrect answers, but should not cause memory errors.
@@ -26,7 +26,7 @@
 **
 ** The virtual table contains read-only hidden columns:
 **
-**     lsm1_key	      A BLOB which is the raw LSM key.  If the "keytype"
+**     lsm1_key       A BLOB which is the raw LSM key.  If the "keytype"
 **                    is BLOB or TEXT then this column is exactly the
 **                    same as the key.  For the UINT keytype, this column
 **                    will be a variable-length integer encoding of the key.
@@ -1475,7 +1475,8 @@ static sqlite3_module amatchModule = {
  0,                      /* xSavepoint */
  0,                      /* xRelease */
  0,                      /* xRollbackTo */
-  0                       /* xShadowName */
+  0,                      /* xShadowName */
+  0                       /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -411,7 +411,8 @@ int sqlite3BinfoRegister(sqlite3 *db){
    0,                           /* xSavepoint */
    0,                           /* xRelease */
    0,                           /* xRollbackTo */
-    0                            /* xShadowName */
+    0,                           /* xShadowName */
+    0                            /* xShadowName2 */
  };
  return sqlite3_create_module(db, "sqlite_btreeinfo", &binfo_module, 0);
 }
@@ -464,7 +464,7 @@ SQLITE_API int sqlite3_carray_bind(
        z += n+1;
      }
    }else{
-      memcpy(pNew->aData, aData, sz*nData);
+      memcpy(pNew->aData, aData, sz);
    }
    pNew->xDel = sqlite3_free;
  }else{
@@ -939,7 +939,8 @@ static sqlite3_module closureModule = {
  0,                      /* xSavepoint */
  0,                      /* xRelease */
  0,                      /* xRollbackTo */
-  0                       /* xShadowName */
+  0,                      /* xShadowName */
+  0                       /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -470,7 +470,8 @@ static sqlite3_module completionModule = {
  0,                         /* xSavepoint */
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
-  0                          /* xShadowName */
+  0,                         /* xShadowName */
+  0                          /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -280,6 +280,7 @@ static char *csv_read_one_field(CsvReader *p){
    }
    p->cTerm = (char)c;
  }
+  assert( p->z==0 || p->n<p->nAlloc );
  if( p->z ) p->z[p->n] = 0;
  p->bNotFirst = 1;
  return p->z;
@@ -750,7 +751,7 @@ static int csvtabNext(sqlite3_vtab_cursor *cur){
      i++;
    }
  }while( pCur->rdr.cTerm==',' );
-  if( z==0 || (pCur->rdr.cTerm==EOF && i<pTab->nCol) ){
+  if( z==0 && i==0 ){
    pCur->iRowid = -1;
  }else{
    pCur->iRowid++;
@@ -811,6 +812,12 @@ static int csvtabFilter(
  CsvCursor *pCur = (CsvCursor*)pVtabCursor;
  CsvTable *pTab = (CsvTable*)pVtabCursor->pVtab;
  pCur->iRowid = 0;
+
+  /* Ensure the field buffer is always allocated. Otherwise, if the
+  ** first field is zero bytes in size, this may be mistaken for an OOM
+  ** error in csvtabNext(). */
+  if( csv_append(&pCur->rdr, 0) ) return SQLITE_NOMEM;
+
  if( pCur->rdr.in==0 ){
    assert( pCur->rdr.zIn==pTab->zData );
    assert( pTab->iStart>=0 );
@@ -941,7 +948,7 @@ int sqlite3_csv_init(
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
 ){
-#ifndef SQLITE_OMIT_VIRTUALTABLE	
+#ifndef SQLITE_OMIT_VIRTUALTABLE
  int rc;
  SQLITE_EXTENSION_INIT2(pApi);
  rc = sqlite3_create_module(db, "csv", &CsvModule, 0);
@@ -828,7 +828,8 @@ static int sqlite3DbdataRegister(sqlite3 *db){
    0,                            /* xSavepoint */
    0,                            /* xRelease */
    0,                            /* xRollbackTo */
-    0                             /* xShadowName */
+    0,                            /* xShadowName */
+    0                             /* xShadowName2 */
  };

  int rc = sqlite3_create_module(db, "sqlite_dbdata", &dbdata_module, 0);
@@ -293,6 +293,7 @@ static sqlite3_module explainModule = {
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadowName */
+  0                          /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -368,10 +368,11 @@ static int writeFile(
  mode_t mode,                    /* MODE parameter passed to writefile() */
  sqlite3_int64 mtime             /* MTIME parameter (or -1 to not set time) */
 ){
+  if( zFile==0 ) return 1;
 #if !defined(_WIN32) && !defined(WIN32)
  if( S_ISLNK(mode) ){
    const char *zTo = (const char*)sqlite3_value_text(pData);
-    if( symlink(zTo, zFile)<0 ) return 1;
+    if( zTo==0 || symlink(zTo, zFile)<0 ) return 1;
  }else
 #endif
  {
@@ -982,6 +983,7 @@ static int fsdirRegister(sqlite3 *db){
    0,                         /* xRelease */
    0,                         /* xRollbackTo */
    0,                         /* xShadowName */
+    0                          /* xShadowName2 */
  };

  int rc = sqlite3_create_module(db, "fsdir", &fsdirModule, 0);
@@ -1035,30 +1035,31 @@ static int deltaparsevtabBestIndex(
 ** virtual table.
 */
 static sqlite3_module deltaparsevtabModule = {
-  /* iVersion    */ 0,
-  /* xCreate     */ 0,
-  /* xConnect    */ deltaparsevtabConnect,
-  /* xBestIndex  */ deltaparsevtabBestIndex,
-  /* xDisconnect */ deltaparsevtabDisconnect,
-  /* xDestroy    */ 0,
-  /* xOpen       */ deltaparsevtabOpen,
-  /* xClose      */ deltaparsevtabClose,
-  /* xFilter     */ deltaparsevtabFilter,
-  /* xNext       */ deltaparsevtabNext,
-  /* xEof        */ deltaparsevtabEof,
-  /* xColumn     */ deltaparsevtabColumn,
-  /* xRowid      */ deltaparsevtabRowid,
-  /* xUpdate     */ 0,
-  /* xBegin      */ 0,
-  /* xSync       */ 0,
-  /* xCommit     */ 0,
-  /* xRollback   */ 0,
-  /* xFindMethod */ 0,
-  /* xRename     */ 0,
-  /* xSavepoint  */ 0,
-  /* xRelease    */ 0,
-  /* xRollbackTo */ 0,
-  /* xShadowName */ 0
+  /* iVersion     */ 0,
+  /* xCreate      */ 0,
+  /* xConnect     */ deltaparsevtabConnect,
+  /* xBestIndex   */ deltaparsevtabBestIndex,
+  /* xDisconnect  */ deltaparsevtabDisconnect,
+  /* xDestroy     */ 0,
+  /* xOpen        */ deltaparsevtabOpen,
+  /* xClose       */ deltaparsevtabClose,
+  /* xFilter      */ deltaparsevtabFilter,
+  /* xNext        */ deltaparsevtabNext,
+  /* xEof         */ deltaparsevtabEof,
+  /* xColumn      */ deltaparsevtabColumn,
+  /* xRowid       */ deltaparsevtabRowid,
+  /* xUpdate      */ 0,
+  /* xBegin       */ 0,
+  /* xSync        */ 0,
+  /* xCommit      */ 0,
+  /* xRollback    */ 0,
+  /* xFindMethod  */ 0,
+  /* xRename      */ 0,
+  /* xSavepoint   */ 0,
+  /* xRelease     */ 0,
+  /* xRollbackTo  */ 0,
+  /* xShadowName  */ 0,
+  /* xShadowName2 */ 0
 };


@@ -284,7 +284,7 @@ int sqlite3_ieee_init(
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){
-    rc = sqlite3_create_function(db, aFunc[i].zFName, aFunc[i].nArg,	
+    rc = sqlite3_create_function(db, aFunc[i].zFName, aFunc[i].nArg,
                               SQLITE_UTF8|SQLITE_INNOCUOUS,
                               (void*)&aFunc[i].iAux,
                               aFunc[i].xFunc, 0, 0);
@@ -396,6 +396,7 @@ static sqlite3_module memstatModule = {
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadowName */
+  0                          /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -225,30 +225,31 @@ static int prefixesBestIndex(
 ** virtual table.
 */
 static sqlite3_module prefixesModule = {
-  /* iVersion    */ 0,
-  /* xCreate     */ 0,
-  /* xConnect    */ prefixesConnect,
-  /* xBestIndex  */ prefixesBestIndex,
-  /* xDisconnect */ prefixesDisconnect,
-  /* xDestroy    */ 0,
-  /* xOpen       */ prefixesOpen,
-  /* xClose      */ prefixesClose,
-  /* xFilter     */ prefixesFilter,
-  /* xNext       */ prefixesNext,
-  /* xEof        */ prefixesEof,
-  /* xColumn     */ prefixesColumn,
-  /* xRowid      */ prefixesRowid,
-  /* xUpdate     */ 0,
-  /* xBegin      */ 0,
-  /* xSync       */ 0,
-  /* xCommit     */ 0,
-  /* xRollback   */ 0,
-  /* xFindMethod */ 0,
-  /* xRename     */ 0,
-  /* xSavepoint  */ 0,
-  /* xRelease    */ 0,
-  /* xRollbackTo */ 0,
-  /* xShadowName */ 0
+  /* iVersion     */ 0,
+  /* xCreate      */ 0,
+  /* xConnect     */ prefixesConnect,
+  /* xBestIndex   */ prefixesBestIndex,
+  /* xDisconnect  */ prefixesDisconnect,
+  /* xDestroy     */ 0,
+  /* xOpen        */ prefixesOpen,
+  /* xClose       */ prefixesClose,
+  /* xFilter      */ prefixesFilter,
+  /* xNext        */ prefixesNext,
+  /* xEof         */ prefixesEof,
+  /* xColumn      */ prefixesColumn,
+  /* xRowid       */ prefixesRowid,
+  /* xUpdate      */ 0,
+  /* xBegin       */ 0,
+  /* xSync        */ 0,
+  /* xCommit      */ 0,
+  /* xRollback    */ 0,
+  /* xFindMethod  */ 0,
+  /* xRename      */ 0,
+  /* xSavepoint   */ 0,
+  /* xRelease     */ 0,
+  /* xRollbackTo  */ 0,
+  /* xShadowName  */ 0,
+  /* xShadowName2 */ 0
 };

 /*
@@ -0,0 +1,462 @@
+/*
+** 2022-01-19
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements a virtual-table that returns information about
+** how the query planner called the xBestIndex method.  This virtual table
+** is intended for testing and debugging only.
+**
+** The schema of the virtual table is this:
+**
+**    CREATE TABLE qpvtab(
+**      vn     TEXT,           -- Name of an sqlite3_index_info field
+**      ix     INTEGER,        -- Array index or value
+**      cn     TEXT,           -- Column name
+**      op     INTEGER,        -- operator
+**      ux     BOOLEAN,        -- "usable" field
+**      rhs    TEXT,           -- sqlite3_vtab_rhs_value()
+**
+**      a, b, c, d, e,         -- Extra columns to attach constraints to
+**
+**      flags    INTEGER HIDDEN  -- control flags
+**    );
+**
+** The virtual table returns a description of the sqlite3_index_info object
+** that was provided to the (successful) xBestIndex method.  There is one
+** row in the result table for each field in the sqlite3_index_info object.
+**
+** The values of the "a" through "e" columns are one of:
+**
+**    1.   TEXT - the same as the column name
+**    2.   INTEGER - 1 for "a", 2 for "b", and so forth
+**
+** Option 1 is the default behavior.  2 is use if there is a usable
+** constraint on "flags" with an integer right-hand side that where the
+** value of the right-hand side has its 0x001 bit set.
+**
+** All constraints on columns "a" through "e" are marked as "omit".
+**
+** If there is a usable constraint on "flags" that has a RHS value that
+** is an integer and that integer has its 0x02 bit set, then the
+** orderByConsumed flag is set.
+**
+** FLAGS SUMMARY:
+**
+**   0x001               Columns 'a' through 'e' have INT values
+**   0x002               orderByConsumed is set
+**   0x004               OFFSET and LIMIT have omit set
+**
+** COMPILE:
+**
+**   gcc -Wall -g -shared -fPIC -I. qpvtab.c -o qqvtab.so
+**
+** EXAMPLE USAGE:
+**
+**   .load ./qpvtab
+**   SELECT rowid, *, flags FROM qpvtab(102)
+**    WHERE a=19
+**      AND b BETWEEN 4.5 and 'hello'
+**      AND c<>x'aabbcc'
+**    ORDER BY d, e DESC;
+*/
+#if !defined(SQLITEINT_H)
+#include "sqlite3ext.h"
+#endif
+SQLITE_EXTENSION_INIT1
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+
+#if !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+/* qpvtab_vtab is a subclass of sqlite3_vtab which is
+** underlying representation of the virtual table
+*/
+typedef struct qpvtab_vtab qpvtab_vtab;
+struct qpvtab_vtab {
+  sqlite3_vtab base;  /* Base class - must be first */
+};
+
+/* qpvtab_cursor is a subclass of sqlite3_vtab_cursor which will
+** serve as the underlying representation of a cursor that scans
+** over rows of the result
+*/
+typedef struct qpvtab_cursor qpvtab_cursor;
+struct qpvtab_cursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  sqlite3_int64 iRowid;      /* The rowid */
+  const char *zData;         /* Data to return */
+  int nData;                 /* Number of bytes of data */
+  int flags;                 /* Flags value */
+};
+
+/*
+** Names of columns
+*/
+static const char *azColname[] = {
+  "vn",
+  "ix",
+  "cn",
+  "op",
+  "ux",
+  "rhs",
+  "a", "b", "c", "d", "e",
+  "flags",
+  ""
+};
+
+/*
+** The qpvtabConnect() method is invoked to create a new
+** qpvtab virtual table.
+*/
+static int qpvtabConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  qpvtab_vtab *pNew;
+  int rc;
+
+  rc = sqlite3_declare_vtab(db,
+         "CREATE TABLE x("
+         " vn TEXT,"
+         " ix INT,"
+         " cn TEXT,"
+         " op INT,"
+         " ux BOOLEAN,"
+         " rhs TEXT,"
+         " a, b, c, d, e,"
+         " flags INT HIDDEN)"
+       );
+#define QPVTAB_VN      0
+#define QPVTAB_IX      1
+#define QPVTAB_CN      2
+#define QPVTAB_OP      3
+#define QPVTAB_UX      4
+#define QPVTAB_RHS     5
+#define QPVTAB_A       6
+#define QPVTAB_B       7
+#define QPVTAB_C       8
+#define QPVTAB_D       9
+#define QPVTAB_E      10
+#define QPVTAB_FLAGS  11
+#define QPVTAB_NONE   12
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3_malloc( sizeof(*pNew) );
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(*pNew));
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for qpvtab_vtab objects.
+*/
+static int qpvtabDisconnect(sqlite3_vtab *pVtab){
+  qpvtab_vtab *p = (qpvtab_vtab*)pVtab;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new qpvtab_cursor object.
+*/
+static int qpvtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  qpvtab_cursor *pCur;
+  pCur = sqlite3_malloc( sizeof(*pCur) );
+  if( pCur==0 ) return SQLITE_NOMEM;
+  memset(pCur, 0, sizeof(*pCur));
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destructor for a qpvtab_cursor.
+*/
+static int qpvtabClose(sqlite3_vtab_cursor *cur){
+  qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+  sqlite3_free(pCur);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a qpvtab_cursor to its next row of output.
+*/
+static int qpvtabNext(sqlite3_vtab_cursor *cur){
+  qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+  if( pCur->iRowid<pCur->nData ){
+    const char *z = &pCur->zData[pCur->iRowid];
+    const char *zEnd = strchr(z, '\n');
+    if( zEnd ) zEnd++;
+    pCur->iRowid = (int)(zEnd - pCur->zData);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return values of columns for the row at which the qpvtab_cursor
+** is currently pointing.
+*/
+static int qpvtabColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+  if( i>=QPVTAB_VN && i<=QPVTAB_RHS && pCur->iRowid<pCur->nData ){
+    const char *z = &pCur->zData[pCur->iRowid];
+    const char *zEnd;
+    int j;
+    j = QPVTAB_VN;
+    while(1){
+      zEnd = strchr(z, j==QPVTAB_RHS ? '\n' : ',');
+      if( j==i || zEnd==0 ) break;
+      z = zEnd+1;
+      j++;
+    }
+    if( zEnd==z ){
+      sqlite3_result_null(ctx);
+    }else if( i==QPVTAB_IX || i==QPVTAB_OP || i==QPVTAB_UX ){
+      sqlite3_result_int(ctx, atoi(z));
+    }else{
+      sqlite3_result_text64(ctx, z, zEnd-z, SQLITE_TRANSIENT, SQLITE_UTF8);
+    }
+  }else if( i>=QPVTAB_A && i<=QPVTAB_E ){
+    if( pCur->flags & 0x001 ){
+      sqlite3_result_int(ctx, i-QPVTAB_A+1);
+    }else{
+      char x = 'a'+i-QPVTAB_A;
+      sqlite3_result_text64(ctx, &x, 1, SQLITE_TRANSIENT, SQLITE_UTF8);
+    }
+  }else if( i==QPVTAB_FLAGS ){
+    sqlite3_result_int(ctx, pCur->flags);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the rowid for the current row.  In this implementation, the
+** rowid is the same as the output value.
+*/
+static int qpvtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+  *pRowid = pCur->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int qpvtabEof(sqlite3_vtab_cursor *cur){
+  qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+  return pCur->iRowid>=pCur->nData;
+}
+
+/*
+** This method is called to "rewind" the qpvtab_cursor object back
+** to the first row of output.  This method is always called at least
+** once prior to any call to qpvtabColumn() or qpvtabRowid() or 
+** qpvtabEof().
+*/
+static int qpvtabFilter(
+  sqlite3_vtab_cursor *pVtabCursor, 
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  qpvtab_cursor *pCur = (qpvtab_cursor *)pVtabCursor;
+  pCur->iRowid = 0;
+  pCur->zData = idxStr;
+  pCur->nData = (int)strlen(idxStr);
+  pCur->flags = idxNum;
+  return SQLITE_OK;
+}
+
+/*
+** Append the text of a value to pStr
+*/
+static void qpvtabStrAppendValue(
+  sqlite3_str *pStr,
+  sqlite3_value *pVal
+){
+  switch( sqlite3_value_type(pVal) ){
+    case SQLITE_NULL:
+      sqlite3_str_appendf(pStr, "NULL");
+      break;
+    case SQLITE_INTEGER:
+      sqlite3_str_appendf(pStr, "%lld", sqlite3_value_int64(pVal));
+      break;
+    case SQLITE_FLOAT:
+      sqlite3_str_appendf(pStr, "%!f", sqlite3_value_double(pVal));
+      break;
+    case SQLITE_TEXT: {
+      int i;
+      const char *a = (const char*)sqlite3_value_text(pVal);
+      int n = sqlite3_value_bytes(pVal);
+      sqlite3_str_append(pStr, "'", 1);
+      for(i=0; i<n; i++){
+        char c = a[i];
+        if( c=='\n' ) c = ' ';
+        sqlite3_str_append(pStr, &c, 1);
+        if( c=='\'' ) sqlite3_str_append(pStr, &c, 1);
+      }
+      sqlite3_str_append(pStr, "'", 1);
+      break;
+    }
+    case SQLITE_BLOB: {
+      int i;
+      const unsigned char *a = sqlite3_value_blob(pVal);
+      int n = sqlite3_value_bytes(pVal);
+      sqlite3_str_append(pStr, "x'", 2);
+      for(i=0; i<n; i++){
+        sqlite3_str_appendf(pStr, "%02x", a[i]);
+      }
+      sqlite3_str_append(pStr, "'", 1);
+      break;
+    }
+  }
+}
+
+/*
+** SQLite will invoke this method one or more times while planning a query
+** that uses the virtual table.  This routine needs to create
+** a query plan for each invocation and compute an estimated cost for that
+** plan.
+*/
+static int qpvtabBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  sqlite3_str *pStr = sqlite3_str_new(0);
+  int i, k = 0;
+  int rc;
+  sqlite3_str_appendf(pStr, "nConstraint,%d,,,,\n", pIdxInfo->nConstraint);
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    sqlite3_value *pVal;
+    int iCol = pIdxInfo->aConstraint[i].iColumn;
+    int op = pIdxInfo->aConstraint[i].op;
+    if( iCol==QPVTAB_FLAGS &&  pIdxInfo->aConstraint[i].usable ){
+      pVal = 0;
+      rc = sqlite3_vtab_rhs_value(pIdxInfo, i, &pVal);
+      assert( rc==SQLITE_OK || pVal==0 );
+      if( pVal ){
+        pIdxInfo->idxNum = sqlite3_value_int(pVal);
+        if( pIdxInfo->idxNum & 0x002 ) pIdxInfo->orderByConsumed = 1;
+      }
+    }
+    if( op==SQLITE_INDEX_CONSTRAINT_LIMIT
+     || op==SQLITE_INDEX_CONSTRAINT_OFFSET
+    ){
+      iCol = QPVTAB_NONE;
+    }
+    sqlite3_str_appendf(pStr,"aConstraint,%d,%s,%d,%d,",
+       i,
+       azColname[iCol],
+       op,
+       pIdxInfo->aConstraint[i].usable);
+    pVal = 0;
+    rc = sqlite3_vtab_rhs_value(pIdxInfo, i, &pVal);
+    assert( rc==SQLITE_OK || pVal==0 );
+    if( pVal ){
+      qpvtabStrAppendValue(pStr, pVal);
+    }
+    sqlite3_str_append(pStr, "\n", 1);
+  }
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    int iCol = pIdxInfo->aConstraint[i].iColumn;
+    int op = pIdxInfo->aConstraint[i].op;
+    if( op==SQLITE_INDEX_CONSTRAINT_LIMIT
+     || op==SQLITE_INDEX_CONSTRAINT_OFFSET
+    ){
+      iCol = QPVTAB_NONE;
+    }
+    if( iCol>=QPVTAB_A && pIdxInfo->aConstraint[i].usable ){
+      pIdxInfo->aConstraintUsage[i].argvIndex = ++k;
+      if( iCol<=QPVTAB_FLAGS || (pIdxInfo->idxNum & 0x004)!=0 ){
+        pIdxInfo->aConstraintUsage[i].omit = 1;
+      }
+    }
+  }
+  sqlite3_str_appendf(pStr, "nOrderBy,%d,,,,\n", pIdxInfo->nOrderBy);
+  for(i=0; i<pIdxInfo->nOrderBy; i++){
+    int iCol = pIdxInfo->aOrderBy[i].iColumn;
+    sqlite3_str_appendf(pStr, "aOrderBy,%d,%s,%d,,\n",i,
+      iCol>=0 ? azColname[iCol] : "rowid",
+      pIdxInfo->aOrderBy[i].desc
+    );
+  }
+  sqlite3_str_appendf(pStr, "sqlite3_vtab_distinct,%d,,,,\n", 
+                      sqlite3_vtab_distinct(pIdxInfo));
+  sqlite3_str_appendf(pStr, "idxFlags,%d,,,,\n", pIdxInfo->idxFlags);
+  sqlite3_str_appendf(pStr, "colUsed,%d,,,,\n", (int)pIdxInfo->colUsed);
+  pIdxInfo->estimatedCost = (double)10;
+  pIdxInfo->estimatedRows = 10;
+  sqlite3_str_appendf(pStr, "idxNum,%d,,,,\n", pIdxInfo->idxNum);
+  sqlite3_str_appendf(pStr, "orderByConsumed,%d,,,,\n",
+                      pIdxInfo->orderByConsumed);
+  pIdxInfo->idxStr = sqlite3_str_finish(pStr);
+  pIdxInfo->needToFreeIdxStr = 1;
+  return SQLITE_OK;
+}
+
+/*
+** This following structure defines all the methods for the 
+** virtual table.
+*/
+static sqlite3_module qpvtabModule = {
+  /* iVersion     */ 0,
+  /* xCreate      */ 0,
+  /* xConnect     */ qpvtabConnect,
+  /* xBestIndex   */ qpvtabBestIndex,
+  /* xDisconnect  */ qpvtabDisconnect,
+  /* xDestroy     */ 0,
+  /* xOpen        */ qpvtabOpen,
+  /* xClose       */ qpvtabClose,
+  /* xFilter      */ qpvtabFilter,
+  /* xNext        */ qpvtabNext,
+  /* xEof         */ qpvtabEof,
+  /* xColumn      */ qpvtabColumn,
+  /* xRowid       */ qpvtabRowid,
+  /* xUpdate      */ 0,
+  /* xBegin       */ 0,
+  /* xSync        */ 0,
+  /* xCommit      */ 0,
+  /* xRollback    */ 0,
+  /* xFindMethod  */ 0,
+  /* xRename      */ 0,
+  /* xSavepoint   */ 0,
+  /* xRelease     */ 0,
+  /* xRollbackTo  */ 0,
+  /* xShadowName  */ 0,
+  /* xShadowName2 */ 0
+};
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_qpvtab_init(
+  sqlite3 *db, 
+  char **pzErrMsg, 
+  const sqlite3_api_routines *pApi
+){
+  int rc = SQLITE_OK;
+  SQLITE_EXTENSION_INIT2(pApi);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  rc = sqlite3_create_module(db, "qpvtab", &qpvtabModule, 0);
+#endif
+  return rc;
+}
@@ -72,6 +72,7 @@ SQLITE_EXTENSION_INIT1

 /* The end-of-input character */
 #define RE_EOF            0    /* End of input */
+#define RE_START  0xfffffff    /* Start of input - larger than an UTF-8 */

 /* The NFA is implemented as sequence of opcodes taken from the following
 ** set.  Each opcode has a single integer argument.
@@ -93,6 +94,33 @@ SQLITE_EXTENSION_INIT1
 #define RE_OP_SPACE      15    /* space:  [ \t\n\r\v\f] */
 #define RE_OP_NOTSPACE   16    /* Not a digit */
 #define RE_OP_BOUNDARY   17    /* Boundary between word and non-word */
+#define RE_OP_ATSTART    18    /* Currently at the start of the string */
+
+#if defined(SQLITE_DEBUG)
+/* Opcode names used for symbolic debugging */
+static const char *ReOpName[] = {
+  "EOF",
+  "MATCH",
+  "ANY",
+  "ANYSTAR",
+  "FORK",
+  "GOTO",
+  "ACCEPT",
+  "CC_INC",
+  "CC_EXC",
+  "CC_VALUE",
+  "CC_RANGE",
+  "WORD",
+  "NOTWORD",
+  "DIGIT",
+  "NOTDIGIT",
+  "SPACE",
+  "NOTSPACE",
+  "BOUNDARY",
+  "ATSTART",
+};
+#endif /* SQLITE_DEBUG */
+

 /* Each opcode is a "state" in the NFA */
 typedef unsigned short ReStateNumber;
@@ -127,7 +155,7 @@ struct ReCompiled {
  int *aArg;                  /* Arguments to each operator */
  unsigned (*xNextChar)(ReInput*);  /* Next character function */
  unsigned char zInit[12];    /* Initial text to match */
-  int nInit;                  /* Number of characters in zInit */
+  int nInit;                  /* Number of bytes in zInit */
  unsigned nState;            /* Number of entries in aOp[] and aArg[] */
  unsigned nAlloc;            /* Slots allocated for aOp[] and aArg[] */
 };
@@ -200,7 +228,7 @@ static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
  ReStateNumber *pToFree;
  unsigned int i = 0;
  unsigned int iSwap = 0;
-  int c = RE_EOF+1;
+  int c = RE_START;
  int cPrev = 0;
  int rc = 0;
  ReInput in;
@@ -219,6 +247,7 @@ static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
      in.i++;
    }
    if( in.i+pRe->nInit>in.mx ) return 0;
+    c = RE_START-1;
  }

  if( pRe->nState<=(sizeof(aSpace)/(sizeof(aSpace[0])*2)) ){
@@ -247,6 +276,10 @@ static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
          if( pRe->aArg[x]==c ) re_add_state(pNext, x+1);
          break;
        }
+        case RE_OP_ATSTART: {
+          if( cPrev==RE_START ) re_add_state(pThis, x+1);
+          break;
+        }
        case RE_OP_ANY: {
          if( c!=0 ) re_add_state(pNext, x+1);
          break;
@@ -299,9 +332,9 @@ static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
        }
        case RE_OP_CC_EXC: {
          if( c==0 ) break;
-          /* fall-through */
+          /* fall-through */ goto re_op_cc_inc;
        }
-        case RE_OP_CC_INC: {
+        case RE_OP_CC_INC: re_op_cc_inc: {
          int j = 1;
          int n = pRe->aArg[x];
          int hit = 0;
@@ -328,7 +361,9 @@ static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
    }
  }
  for(i=0; i<pNext->nState; i++){
-    if( pRe->aOp[pNext->aState[i]]==RE_OP_ACCEPT ){ rc = 1; break; }
+    int x = pNext->aState[i];
+    while( pRe->aOp[x]==RE_OP_GOTO ) x += pRe->aArg[x];
+    if( pRe->aOp[x]==RE_OP_ACCEPT ){ rc = 1; break; }
  }
 re_match_end:
  sqlite3_free(pToFree);
@@ -483,7 +518,6 @@ static const char *re_subcompile_string(ReCompiled *p){
    iStart = p->nState;
    switch( c ){
      case '|':
-      case '$':
      case ')': {
        p->sIn.i--;
        return 0;
@@ -520,6 +554,14 @@ static const char *re_subcompile_string(ReCompiled *p){
        re_insert(p, iPrev, RE_OP_FORK, p->nState - iPrev+1);
        break;
      }
+      case '$': {
+        re_append(p, RE_OP_MATCH, RE_EOF);
+        break;
+      }
+      case '^': {
+        re_append(p, RE_OP_ATSTART, 0);
+        break;
+      }
      case '{': {
        int m = 0, n = 0;
        int sz, j;
@@ -538,6 +580,7 @@ static const char *re_subcompile_string(ReCompiled *p){
        if( m==0 ){
          if( n==0 ) return "both m and n are zero in '{m,n}'";
          re_insert(p, iPrev, RE_OP_FORK, sz+1);
+          iPrev++;
          n--;
        }else{
          for(j=1; j<m; j++) re_copy(p, iPrev, sz);
@@ -656,11 +699,7 @@ static const char *re_compile(ReCompiled **ppRe, const char *zIn, int noCase){
    re_free(pRe);
    return zErr;
  }
-  if( rePeek(pRe)=='$' && pRe->sIn.i+1>=pRe->sIn.mx ){
-    re_append(pRe, RE_OP_MATCH, RE_EOF);
-    re_append(pRe, RE_OP_ACCEPT, 0);
-    *ppRe = pRe;
-  }else if( pRe->sIn.i>=pRe->sIn.mx ){
+  if( pRe->sIn.i>=pRe->sIn.mx ){
    re_append(pRe, RE_OP_ACCEPT, 0);
    *ppRe = pRe;
  }else{
@@ -685,7 +724,7 @@ static const char *re_compile(ReCompiled **ppRe, const char *zIn, int noCase){
        pRe->zInit[j++] = (unsigned char)(0xc0 | (x>>6));
        pRe->zInit[j++] = 0x80 | (x&0x3f);
      }else if( x<=0xffff ){
-        pRe->zInit[j++] = (unsigned char)(0xd0 | (x>>12));
+        pRe->zInit[j++] = (unsigned char)(0xe0 | (x>>12));
        pRe->zInit[j++] = 0x80 | ((x>>6)&0x3f);
        pRe->zInit[j++] = 0x80 | (x&0x3f);
      }else{
@@ -744,6 +783,67 @@ static void re_sql_func(
  }
 }

+#if defined(SQLITE_DEBUG)
+/*
+** This function is used for testing and debugging only.  It is only available
+** if the SQLITE_DEBUG compile-time option is used.
+**
+** Compile a regular expression and then convert the compiled expression into
+** text and return that text.
+*/
+static void re_bytecode_func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zPattern;
+  const char *zErr;
+  ReCompiled *pRe;
+  sqlite3_str *pStr;
+  int i;
+  int n;
+  char *z;
+
+  zPattern = (const char*)sqlite3_value_text(argv[0]);
+  if( zPattern==0 ) return;
+  zErr = re_compile(&pRe, zPattern, sqlite3_user_data(context)!=0);
+  if( zErr ){
+    re_free(pRe);
+    sqlite3_result_error(context, zErr, -1);
+    return;
+  }
+  if( pRe==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  pStr = sqlite3_str_new(0);
+  if( pStr==0 ) goto re_bytecode_func_err;
+  if( pRe->nInit>0 ){
+    sqlite3_str_appendf(pStr, "INIT     ");
+    for(i=0; i<pRe->nInit; i++){
+      sqlite3_str_appendf(pStr, "%02x", pRe->zInit[i]);
+    }
+    sqlite3_str_appendf(pStr, "\n");
+  }
+  for(i=0; (unsigned)i<pRe->nState; i++){
+    sqlite3_str_appendf(pStr, "%-8s %4d\n",
+         ReOpName[(unsigned char)pRe->aOp[i]], pRe->aArg[i]);
+  }
+  n = sqlite3_str_length(pStr);
+  z = sqlite3_str_finish(pStr);
+  if( n==0 ){
+    sqlite3_free(z);
+  }else{
+    sqlite3_result_text(context, z, n-1, sqlite3_free);
+  }
+
+re_bytecode_func_err:
+  re_free(pRe);
+}
+
+#endif /* SQLITE_DEBUG */
+
+
 /*
 ** Invoke this routine to register the regexp() function with the
 ** SQLite database connection.
@@ -759,13 +859,22 @@ int sqlite3_regexp_init(
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused */
-  rc = sqlite3_create_function(db, "regexp", 2, SQLITE_UTF8|SQLITE_INNOCUOUS,
-                               0, re_sql_func, 0, 0);
+  rc = sqlite3_create_function(db, "regexp", 2, 
+                            SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
+                            0, re_sql_func, 0, 0);
  if( rc==SQLITE_OK ){
    /* The regexpi(PATTERN,STRING) function is a case-insensitive version
    ** of regexp(PATTERN,STRING). */
-    rc = sqlite3_create_function(db, "regexpi", 2, SQLITE_UTF8|SQLITE_INNOCUOUS,
-                                 (void*)db, re_sql_func, 0, 0);
+    rc = sqlite3_create_function(db, "regexpi", 2,
+                            SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
+                            (void*)db, re_sql_func, 0, 0);
+#if defined(SQLITE_DEBUG)
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(db, "regexp_bytecode", 1,
+                            SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
+                            0, re_bytecode_func, 0, 0);
+    }
+#endif /* SQLITE_DEBUG */
  }
  return rc;
 }
@@ -386,7 +386,7 @@ static int seriesBestIndex(
    ** the preferred case */
    pIdxInfo->estimatedCost = (double)(2 - ((idxNum&4)!=0));
    pIdxInfo->estimatedRows = 1000;
-    if( pIdxInfo->nOrderBy==1 ){
+    if( pIdxInfo->nOrderBy>=1 && pIdxInfo->aOrderBy[0].iColumn==0 ){
      if( pIdxInfo->aOrderBy[0].desc ){
        idxNum |= 8;
      }else{
@@ -432,7 +432,8 @@ static sqlite3_module seriesModule = {
  0,                         /* xSavepoint */
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
-  0                          /* xShadowName */
+  0,                         /* xShadowName */
+  0                          /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -71,7 +71,7 @@ struct SHA1Context {
 /*
 * Hash a single 512-bit block. This is the core of the algorithm.
 */
-void SHA1Transform(unsigned int state[5], const unsigned char buffer[64]){
+static void SHA1Transform(unsigned int state[5], const unsigned char buffer[64]){
  unsigned int qq[5]; /* a, b, c, d, e; */
  static int one = 1;
  unsigned int block[16];
@@ -19,7 +19,7 @@
 ** The sha3(X) function computes the SHA3 hash of the input X, or NULL if
 ** X is NULL.
 **
-** The sha3_query(Y) function evalutes all queries in the SQL statements of Y
+** The sha3_query(Y) function evaluates all queries in the SQL statements of Y
 ** and returns a hash of their results.
 **
 ** The SIZE argument is optional.  If omitted, the SHA3-256 hash algorithm
@@ -436,6 +436,7 @@ static void SHA3Update(
  unsigned int nData
 ){
  unsigned int i = 0;
+  if( aData==0 ) return;
 #if SHA3_BYTEORDER==1234
  if( (p->nLoaded % 8)==0 && ((aData - (const unsigned char*)0)&7)==0 ){
    for(; i+7<nData; i+=8){
@@ -30,6 +30,16 @@ SQLITE_EXTENSION_INIT1

 #ifndef SQLITE_OMIT_VIRTUALTABLE

+
+#define STMT_NUM_INTEGER_COLUMN 10
+typedef struct StmtRow StmtRow;
+struct StmtRow {
+  sqlite3_int64 iRowid;                /* Rowid value */
+  char *zSql;                          /* column "sql" */
+  int aCol[STMT_NUM_INTEGER_COLUMN+1]; /* all other column values */
+  StmtRow *pNext;                      /* Next row to return */
+};
+
 /* stmt_vtab is a subclass of sqlite3_vtab which will
 ** serve as the underlying representation of a stmt virtual table
 */
@@ -47,8 +57,7 @@ typedef struct stmt_cursor stmt_cursor;
 struct stmt_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  sqlite3 *db;               /* Database connection for this cursor */
-  sqlite3_stmt *pStmt;       /* Statement cursor is currently pointing at */
-  sqlite3_int64 iRowid;      /* The rowid */
+  StmtRow *pRow;             /* Current row */
 };

 /*
@@ -92,7 +101,7 @@ static int stmtConnect(
     "CREATE TABLE x(sql,ncol,ro,busy,nscan,nsort,naidx,nstep,"
                    "reprep,run,mem)");
  if( rc==SQLITE_OK ){
-    pNew = sqlite3_malloc( sizeof(*pNew) );
+    pNew = sqlite3_malloc64( sizeof(*pNew) );
    *ppVtab = (sqlite3_vtab*)pNew;
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
@@ -114,7 +123,7 @@ static int stmtDisconnect(sqlite3_vtab *pVtab){
 */
 static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  stmt_cursor *pCur;
-  pCur = sqlite3_malloc( sizeof(*pCur) );
+  pCur = sqlite3_malloc64( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  pCur->db = ((stmt_vtab*)p)->db;
@@ -122,10 +131,21 @@ static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  return SQLITE_OK;
 }

+static void stmtCsrReset(stmt_cursor *pCur){
+  StmtRow *pRow = 0;
+  StmtRow *pNext = 0;
+  for(pRow=pCur->pRow; pRow; pRow=pNext){
+    pNext = pRow->pNext;
+    sqlite3_free(pRow);
+  }
+  pCur->pRow = 0;
+}
+
 /*
 ** Destructor for a stmt_cursor.
 */
 static int stmtClose(sqlite3_vtab_cursor *cur){
+  stmtCsrReset((stmt_cursor*)cur);
  sqlite3_free(cur);
  return SQLITE_OK;
 }
@@ -136,8 +156,9 @@ static int stmtClose(sqlite3_vtab_cursor *cur){
 */
 static int stmtNext(sqlite3_vtab_cursor *cur){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  pCur->iRowid++;
-  pCur->pStmt = sqlite3_next_stmt(pCur->db, pCur->pStmt);
+  StmtRow *pNext = pCur->pRow->pNext;
+  sqlite3_free(pCur->pRow);
+  pCur->pRow = pNext;
  return SQLITE_OK;
 }

@@ -151,39 +172,11 @@ static int stmtColumn(
  int i                       /* Which column to return */
 ){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  switch( i ){
-    case STMT_COLUMN_SQL: {
-      sqlite3_result_text(ctx, sqlite3_sql(pCur->pStmt), -1, SQLITE_TRANSIENT);
-      break;
-    }
-    case STMT_COLUMN_NCOL: {
-      sqlite3_result_int(ctx, sqlite3_column_count(pCur->pStmt));
-      break;
-    }
-    case STMT_COLUMN_RO: {
-      sqlite3_result_int(ctx, sqlite3_stmt_readonly(pCur->pStmt));
-      break;
-    }
-    case STMT_COLUMN_BUSY: {
-      sqlite3_result_int(ctx, sqlite3_stmt_busy(pCur->pStmt));
-      break;
-    }
-    default: {
-      assert( i==STMT_COLUMN_MEM );
-      i = SQLITE_STMTSTATUS_MEMUSED + 
-            STMT_COLUMN_NSCAN - SQLITE_STMTSTATUS_FULLSCAN_STEP;
-      /* Fall thru */
-    }
-    case STMT_COLUMN_NSCAN:
-    case STMT_COLUMN_NSORT:
-    case STMT_COLUMN_NAIDX:
-    case STMT_COLUMN_NSTEP:
-    case STMT_COLUMN_REPREP:
-    case STMT_COLUMN_RUN: {
-      sqlite3_result_int(ctx, sqlite3_stmt_status(pCur->pStmt,
-                      i-STMT_COLUMN_NSCAN+SQLITE_STMTSTATUS_FULLSCAN_STEP, 0));
-      break;
-    }
+  StmtRow *pRow = pCur->pRow;
+  if( i==STMT_COLUMN_SQL ){
+    sqlite3_result_text(ctx, pRow->zSql, -1, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_int(ctx, pRow->aCol[i]);
  }
  return SQLITE_OK;
 }
@@ -194,7 +187,7 @@ static int stmtColumn(
 */
 static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  *pRowid = pCur->iRowid;
+  *pRowid = pCur->pRow->iRowid;
  return SQLITE_OK;
 }

@@ -204,7 +197,7 @@ static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
 */
 static int stmtEof(sqlite3_vtab_cursor *cur){
  stmt_cursor *pCur = (stmt_cursor*)cur;
-  return pCur->pStmt==0;
+  return pCur->pRow==0;
 }

 /*
@@ -219,9 +212,53 @@ static int stmtFilter(
  int argc, sqlite3_value **argv
 ){
  stmt_cursor *pCur = (stmt_cursor *)pVtabCursor;
-  pCur->pStmt = 0;
-  pCur->iRowid = 0;
-  return stmtNext(pVtabCursor);
+  sqlite3_stmt *p = 0;
+  sqlite3_int64 iRowid = 1;
+  StmtRow **ppRow = 0;
+
+  stmtCsrReset(pCur);
+  ppRow = &pCur->pRow;
+  for(p=sqlite3_next_stmt(pCur->db, 0); p; p=sqlite3_next_stmt(pCur->db, p)){
+    const char *zSql = sqlite3_sql(p);
+    sqlite3_int64 nSql = zSql ? strlen(zSql)+1 : 0;
+    StmtRow *pNew = (StmtRow*)sqlite3_malloc64(sizeof(StmtRow) + nSql);
+
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(StmtRow));
+    if( zSql ){
+      pNew->zSql = (char*)&pNew[1];
+      memcpy(pNew->zSql, zSql, nSql);
+    }
+    pNew->aCol[STMT_COLUMN_NCOL] = sqlite3_column_count(p);
+    pNew->aCol[STMT_COLUMN_RO] = sqlite3_stmt_readonly(p);
+    pNew->aCol[STMT_COLUMN_BUSY] = sqlite3_stmt_busy(p);
+    pNew->aCol[STMT_COLUMN_NSCAN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_FULLSCAN_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSORT] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_SORT, 0
+    );
+    pNew->aCol[STMT_COLUMN_NAIDX] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_AUTOINDEX, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSTEP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_VM_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_REPREP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_REPREPARE, 0
+    );
+    pNew->aCol[STMT_COLUMN_RUN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_RUN, 0
+    );
+    pNew->aCol[STMT_COLUMN_MEM] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_MEMUSED, 0
+    );
+    pNew->iRowid = iRowid++;
+    *ppRow = pNew;
+    ppRow = &pNew->pNext;
+  }
+
+  return SQLITE_OK;
 }

 /*
@@ -268,6 +305,7 @@ static sqlite3_module stmtModule = {
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadowName */
+  0                          /* xShadowName2 */
 };

 #endif /* SQLITE_OMIT_VIRTUALTABLE */
@@ -226,30 +226,31 @@ static int templatevtabBestIndex(
 ** virtual table.
 */
 static sqlite3_module templatevtabModule = {
-  /* iVersion    */ 0,
-  /* xCreate     */ 0,
-  /* xConnect    */ templatevtabConnect,
-  /* xBestIndex  */ templatevtabBestIndex,
-  /* xDisconnect */ templatevtabDisconnect,
-  /* xDestroy    */ 0,
-  /* xOpen       */ templatevtabOpen,
-  /* xClose      */ templatevtabClose,
-  /* xFilter     */ templatevtabFilter,
-  /* xNext       */ templatevtabNext,
-  /* xEof        */ templatevtabEof,
-  /* xColumn     */ templatevtabColumn,
-  /* xRowid      */ templatevtabRowid,
-  /* xUpdate     */ 0,
-  /* xBegin      */ 0,
-  /* xSync       */ 0,
-  /* xCommit     */ 0,
-  /* xRollback   */ 0,
-  /* xFindMethod */ 0,
-  /* xRename     */ 0,
-  /* xSavepoint  */ 0,
-  /* xRelease    */ 0,
-  /* xRollbackTo */ 0,
-  /* xShadowName */ 0
+  /* iVersion     */ 0,
+  /* xCreate      */ 0,
+  /* xConnect     */ templatevtabConnect,
+  /* xBestIndex   */ templatevtabBestIndex,
+  /* xDisconnect  */ templatevtabDisconnect,
+  /* xDestroy     */ 0,
+  /* xOpen        */ templatevtabOpen,
+  /* xClose       */ templatevtabClose,
+  /* xFilter      */ templatevtabFilter,
+  /* xNext        */ templatevtabNext,
+  /* xEof         */ templatevtabEof,
+  /* xColumn      */ templatevtabColumn,
+  /* xRowid       */ templatevtabRowid,
+  /* xUpdate      */ 0,
+  /* xBegin       */ 0,
+  /* xSync        */ 0,
+  /* xCommit      */ 0,
+  /* xRollback    */ 0,
+  /* xFindMethod  */ 0,
+  /* xRename      */ 0,
+  /* xSavepoint   */ 0,
+  /* xRelease     */ 0,
+  /* xRollbackTo  */ 0,
+  /* xShadowName  */ 0,
+  /* xShadowName2 */ 0
 };


@@ -1351,7 +1351,8 @@ static int createUnionVtab(sqlite3 *db){
    0,                            /* xSavepoint */
    0,                            /* xRelease */
    0,                            /* xRollbackTo */
-    0                             /* xShadowName */
+    0,                            /* xShadowName */
+    0                             /* xShadowName2 */
  };
  int rc;

@@ -493,6 +493,7 @@ static sqlite3_module vtablogModule = {
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadowName */
+  0                          /* xShadowName2 */
 };

 #ifdef _WIN32
@@ -425,6 +425,16 @@ static int vtshimRollbackTo(sqlite3_vtab *pBase, int n){
  return rc;
 }

+static int vtshimShadowName2(sqlite3_vtab *pBase, const char *zName){
+  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
+  vtshim_aux *pAux = pVtab->pAux;
+  int rc;
+  if( pAux->bDisposed ) return 0;
+  rc = pAux->pMod->xShadowName2(pVtab->pChild, zName);
+  VTSHIM_COPY_ERRMSG();
+  return rc;
+}
+
 /* The destructor function for a disposible module */
 static void vtshimAuxDestructor(void *pXAux){
  vtshim_aux *pAux = (vtshim_aux*)pXAux;
@@ -481,7 +491,7 @@ void *sqlite3_create_disposable_module(
  pAux->zName = sqlite3_mprintf("%s", zName);
  pAux->bDisposed = 0;
  pAux->pAllVtab = 0;
-  pAux->sSelf.iVersion = p->iVersion<=2 ? p->iVersion : 2;
+  pAux->sSelf.iVersion = p->iVersion<=4 ? p->iVersion : 4;
  pAux->sSelf.xCreate = p->xCreate ? vtshimCreate : 0;
  pAux->sSelf.xConnect = p->xConnect ? vtshimConnect : 0;
  pAux->sSelf.xBestIndex = p->xBestIndex ? vtshimBestIndex : 0;
@@ -510,6 +520,12 @@ void *sqlite3_create_disposable_module(
    pAux->sSelf.xRelease = 0;
    pAux->sSelf.xRollbackTo = 0;
  }
+  pAux->sSelf.xShadowName = 0; /* v3 */
+  if( p->iVersion>=4 ){
+    pAux->sSelf.xShadowName2 = p->xShadowName2 ? vtshimShadowName2 : 0;
+  }else{
+    pAux->sSelf.xShadowName2 = 0;
+  }
  rc = sqlite3_create_module_v2(db, zName, &pAux->sSelf,
                                pAux, vtshimAuxDestructor);
  return rc==SQLITE_OK ? (void*)pAux : 0;
@@ -1262,9 +1262,14 @@ static int zipfileFilter(
    zipfileCursorErr(pCsr, "zipfile() function requires an argument");
    return SQLITE_ERROR;
  }else if( sqlite3_value_type(argv[0])==SQLITE_BLOB ){
+    static const u8 aEmptyBlob = 0;
    const u8 *aBlob = (const u8*)sqlite3_value_blob(argv[0]);
    int nBlob = sqlite3_value_bytes(argv[0]);
    assert( pTab->pFirstEntry==0 );
+    if( aBlob==0 ){
+      aBlob = &aEmptyBlob;
+      nBlob = 0;
+    }
    rc = zipfileLoadDirectory(pTab, aBlob, nBlob);
    pCsr->pFreeEntry = pTab->pFirstEntry;
    pTab->pFirstEntry = pTab->pLastEntry = 0;
@@ -1938,7 +1943,7 @@ static int zipfileBufferGrow(ZipfileBuffer *pBuf, int nByte){
 **   SELECT zipfile(name,mode,mtime,data) ...
 **   SELECT zipfile(name,mode,mtime,data,method) ...
 */
-void zipfileStep(sqlite3_context *pCtx, int nVal, sqlite3_value **apVal){
+static void zipfileStep(sqlite3_context *pCtx, int nVal, sqlite3_value **apVal){
  ZipfileCtx *p;                  /* Aggregate function context */
  ZipfileEntry e;                 /* New entry to add to zip archive */

@@ -2113,7 +2118,7 @@ void zipfileStep(sqlite3_context *pCtx, int nVal, sqlite3_value **apVal){
 /*
 ** xFinalize() callback for zipfile aggregate function.
 */
-void zipfileFinal(sqlite3_context *pCtx){
+static void zipfileFinal(sqlite3_context *pCtx){
  ZipfileCtx *p;
  ZipfileEOCD eocd;
  sqlite3_int64 nZip;
@@ -2170,6 +2175,11 @@ static int zipfileRegister(sqlite3 *db){
    zipfileRollback,           /* xRollback */
    zipfileFindFunction,       /* xFindMethod */
    0,                         /* xRename */
+    0,                         /* xSavepoint */
+    0,                         /* xRelease */
+    0,                         /* xRollback */
+    0,                         /* xShadowName */
+    0                          /* xShadowName2 */
  };

  int rc = sqlite3_create_module(db, "zipfile"  , &zipfileModule, 0);
@@ -0,0 +1,87 @@
+# 2014 August 30
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+source [file join [file dirname [info script]] rbu_common.tcl]
+set ::testprefix rbubusy
+
+db close
+sqlite3_shutdown
+test_sqlite3_log xLog
+reset_db
+
+set db_sql {
+  CREATE TABLE t1(a PRIMARY KEY, b, c);
+  INSERT INTO t1 VALUES(1000, 2000, 3000);
+}
+
+set rbu_sql {
+  CREATE TABLE data_t1(a, b, c, rbu_control);
+  INSERT INTO data_t1 VALUES(1, 2, 3, 0);
+  INSERT INTO data_t1 VALUES(4, 5, 6, 0);
+  INSERT INTO data_t1 VALUES(7, 8, 9, 0);
+}
+
+do_test 1.1 {
+  forcedelete rbu.db
+  sqlite3 rbu rbu.db
+  rbu eval $rbu_sql
+  rbu close
+
+  db eval $db_sql
+} {}
+
+do_execsql_test 1.2 {
+  BEGIN;
+    SELECT * FROM t1
+} {1000 2000 3000}
+
+do_test 1.3 {
+  sqlite3rbu rbu test.db rbu.db
+  rbu step
+} {SQLITE_OK}
+
+do_test 1.4 {
+  while 1 {
+    set rc [rbu step]
+    if {$rc!="SQLITE_OK"} break
+  }
+  set rc
+} {SQLITE_BUSY}
+
+do_test 1.5 {
+  rbu step
+} {SQLITE_BUSY}
+
+do_test 1.6 {
+  db eval COMMIT
+  rbu step
+} {SQLITE_BUSY}
+catch { rbu close }
+
+do_test 1.7 {
+  sqlite3rbu rbu test.db rbu.db
+  while 1 {
+    set rc [rbu step]
+    if {$rc!="SQLITE_OK"} break
+  }
+  set rc
+} {SQLITE_DONE}
+
+rbu close
+
+db close
+sqlite3_shutdown
+test_sqlite3_log 
+sqlite3_initialize
+finish_test
+
@@ -0,0 +1,207 @@
+# 2021 November 06
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+
+source [file join [file dirname [info script]] rbu_common.tcl]
+set ::testprefix rbuexlock
+
+db close
+sqlite3_shutdown
+sqlite3_config_uri 1
+
+# Create a simple RBU database. That expects to write to a table:
+#
+#   CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
+#
+proc create_rbu {filename} {
+  forcedelete $filename
+  sqlite3 rbu1 $filename  
+  rbu1 eval {
+    CREATE TABLE data_t1(a, b, c, rbu_control);
+    INSERT INTO data_t1 VALUES(10, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(20, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(30, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(40, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(50, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(60, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(70, random(), random(), 0);
+    INSERT INTO data_t1 VALUES(80, random(), random(), 0);
+  }
+  rbu1 close
+  return $filename
+}
+
+reset_db
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a PRIMARY KEY, b INT, c INT);
+  CREATE INDEX t1b ON t1(b);
+  CREATE INDEX t1c ON t1(c);
+  INSERT INTO t1 VALUES(1, 2, 3);
+}
+create_rbu rbu1.db
+
+do_test 1.1.0 {
+  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=1 rbu1.db
+  rbu step
+} SQLITE_OK
+do_catchsql_test 1.1.1 { SELECT * FROM t1 } {0 {1 2 3}}
+
+do_test 1.2.0 {
+  for {set ii 0} {$ii < 10} {incr ii} {
+    rbu step
+  }
+  rbu step
+} SQLITE_OK
+do_catchsql_test 1.2.1 { SELECT * FROM t1 } {0 {1 2 3}}
+do_test 1.2.2 {
+  db eval {PRAGMA journal_mode}
+} {delete}
+
+do_test 1.3.0 {
+  while {[file exists test.db-wal]==0} {
+    rbu step
+  }
+} {}
+do_catchsql_test 1.3.1 { SELECT * FROM t1 } {1 {database is locked}}
+do_test 1.3.2 {
+  db eval {PRAGMA journal_mode}
+} {delete}
+
+
+do_test 1.4.0 {
+  rbu step
+} SQLITE_OK
+do_catchsql_test 1.4.1 { SELECT * FROM t1 } {1 {database is locked}}
+do_test 1.4.2 {
+  db eval {PRAGMA journal_mode}
+} {delete}
+
+
+rbu close
+
+do_test 1.5.0 {
+  file exists test.db-wal
+} {1}
+do_test 1.5.1 {
+  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=1 rbu1.db
+  file exists test.db-wal
+} 1
+do_catchsql_test 1.5.2 { SELECT * FROM t1 } {1 {database is locked}}
+do_test 1.5.2 {
+  db eval {PRAGMA journal_mode}
+} {delete}
+
+
+do_test 1.6.0 {
+  rbu step
+} SQLITE_OK
+do_catchsql_test 1.6.1 { SELECT * FROM t1 } {1 {database is locked}}
+do_test 1.6.2 {
+  db eval {PRAGMA journal_mode}
+} {delete}
+
+do_test 1.7.0 {
+  while {[rbu step]=="SQLITE_OK"} {}
+  rbu close
+} SQLITE_DONE
+do_catchsql_test 1.7.2 { SELECT count(*) FROM t1 } {0 9}
+do_test 1.7.2 {
+  db eval {PRAGMA journal_mode}
+} {delete}
+
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE t1(a PRIMARY KEY, b INT, c INT);
+  CREATE INDEX t1b ON t1(b);
+  CREATE INDEX t1c ON t1(c);
+  INSERT INTO t1 VALUES(1, 2, 3);
+}
+create_rbu rbu1.db
+
+do_test 2.1.0 {
+  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
+  rbu step
+} SQLITE_OK
+do_catchsql_test 2.1.1 { SELECT * FROM t1 } {0 {1 2 3}}
+
+do_test 2.2.0 {
+  for {set ii 0} {$ii < 10} {incr ii} {
+    rbu step
+  }
+  rbu step
+} SQLITE_OK
+do_catchsql_test 2.2.1 { SELECT * FROM t1 } {0 {1 2 3}}
+
+do_test 2.3.0 {
+  while {[file exists test.db-wal]==0} {
+    rbu step
+  }
+} {}
+do_test 2.3.1 {
+  llength [db eval {SELECT * FROM t1}]
+} {27}
+do_test 2.3.2 {
+  db eval {PRAGMA journal_mode}
+} {wal}
+
+do_test 2.4.0 {
+  rbu step
+} SQLITE_OK
+do_test 2.4.1 {
+  llength [db eval  {SELECT * FROM t1}]
+} {27}
+do_test 2.4.2 {
+  db eval {PRAGMA journal_mode}
+} {wal}
+
+rbu close
+
+do_test 2.5.0 {
+  db eval {PRAGMA journal_mode}
+} {wal}
+do_execsql_test 2.5.1 {
+  DELETE FROM t1;
+} {}
+
+create_rbu rbu1.db
+do_test 3.1.0 {
+  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
+  rbu step
+} SQLITE_ERROR
+
+do_test 3.1.1 {
+  set rc [catch {rbu close} msg]
+  lappend rc $msg
+} {1 {SQLITE_ERROR - cannot update wal mode database}}
+db eval {PRAGMA journal_mode=DELETE}
+
+create_rbu rbu1.db
+do_test 3.2.0 {
+  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
+  rbu step
+} SQLITE_OK
+
+do_test 3.3.1 {
+  set rc [catch {rbu close} msg]
+  lappend rc $msg
+} {0 SQLITE_OK}
+
+db close
+create_rbu rbu1.db
+do_test 3.4.0 {
+  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
+  rbu step
+} SQLITE_OK
+rbu close
+
+
+finish_test
@@ -198,7 +198,11 @@ if {$::tcl_platform(platform)=="unix"} {
    } {SQLITE_OK}

    do_test 5.$tn.2 { file exists test.db-vacuum } 1
-    do_test 5.$tn.3 { file attributes test.db-vacuum -permissions} $perm
+    # The result pattern might be 00xxx or 0oxxx depending on which
+    # version of TCL is being used.  So make perm2 into a regexp that
+    # will match either
+    regsub {^00} $perm {0.} perm2
+    do_test 5.$tn.3 { file attributes test.db-vacuum -permissions} /$perm2/
    rbu close
  }
 }
@@ -110,6 +110,13 @@
 # define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
 #endif

+/*
+** Name of the URI option that causes RBU to take an exclusive lock as
+** part of the incremental checkpoint operation.
+*/
+#define RBU_EXCLUSIVE_CHECKPOINT "rbu_exclusive_checkpoint"
+
+
 /*
 ** The rbu_state table is used to save the state of a partially applied
 ** update so that it can be resumed later. The table consists of integer
@@ -1556,7 +1563,7 @@ static char *rbuVacuumTableStart(
 ** the caller has to use an OFFSET clause to extract only the required 
 ** rows from the sourct table, just as it does for an RBU update operation.
 */
-char *rbuVacuumIndexStart(
+static char *rbuVacuumIndexStart(
  sqlite3rbu *p,                  /* RBU handle */
  RbuObjIter *pIter               /* RBU iterator object */
 ){
@@ -2756,13 +2763,19 @@ static RbuState *rbuLoadState(sqlite3rbu *p){
 /*
 ** Open the database handle and attach the RBU database as "rbu". If an
 ** error occurs, leave an error code and message in the RBU handle.
+**
+** If argument dbMain is not NULL, then it is a database handle already
+** open on the target database. Use this handle instead of opening a new
+** one.
 */
-static void rbuOpenDatabase(sqlite3rbu *p, int *pbRetry){
+static void rbuOpenDatabase(sqlite3rbu *p, sqlite3 *dbMain, int *pbRetry){
  assert( p->rc || (p->dbMain==0 && p->dbRbu==0) );
  assert( p->rc || rbuIsVacuum(p) || p->zTarget!=0 );
+  assert( dbMain==0 || rbuIsVacuum(p)==0 );

  /* Open the RBU database */
  p->dbRbu = rbuOpenDbhandle(p, p->zRbu, 1);
+  p->dbMain = dbMain;

  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
    sqlite3_file_control(p->dbRbu, "main", SQLITE_FCNTL_RBUCNT, (void*)p);
@@ -3128,15 +3141,31 @@ static void rbuCheckpointFrame(sqlite3rbu *p, RbuFrame *pFrame){


 /*
-** Take an EXCLUSIVE lock on the database file.
+** Take an EXCLUSIVE lock on the database file. Return SQLITE_OK if
+** successful, or an SQLite error code otherwise.
 */
-static void rbuLockDatabase(sqlite3rbu *p){
-  sqlite3_file *pReal = p->pTargetFd->pReal;
-  assert( p->rc==SQLITE_OK );
-  p->rc = pReal->pMethods->xLock(pReal, SQLITE_LOCK_SHARED);
-  if( p->rc==SQLITE_OK ){
-    p->rc = pReal->pMethods->xLock(pReal, SQLITE_LOCK_EXCLUSIVE);
+static int rbuLockDatabase(sqlite3 *db){
+  int rc = SQLITE_OK;
+  sqlite3_file *fd = 0;
+  sqlite3_file_control(db, "main", SQLITE_FCNTL_FILE_POINTER, &fd);
+
+  if( fd->pMethods ){
+    rc = fd->pMethods->xLock(fd, SQLITE_LOCK_SHARED);
+    if( rc==SQLITE_OK ){
+      rc = fd->pMethods->xLock(fd, SQLITE_LOCK_EXCLUSIVE);
+    }
  }
+  return rc;
+}
+
+/*
+** Return true if the database handle passed as the only argument
+** was opened with the rbu_exclusive_checkpoint=1 URI parameter
+** specified. Or false otherwise.
+*/
+static int rbuExclusiveCheckpoint(sqlite3 *db){
+  const char *zUri = sqlite3_db_filename(db, 0);
+  return sqlite3_uri_boolean(zUri, RBU_EXCLUSIVE_CHECKPOINT, 0);
 }

 #if defined(_WIN32_WCE)
@@ -3194,18 +3223,24 @@ static void rbuMoveOalFile(sqlite3rbu *p){
    ** In order to ensure that there are no database readers, an EXCLUSIVE
    ** lock is obtained here before the *-oal is moved to *-wal.
    */
-    rbuLockDatabase(p);
+    sqlite3 *dbMain = 0;
+    rbuFileSuffix3(zBase, zWal);
+    rbuFileSuffix3(zBase, zOal);
+
+    /* Re-open the databases. */
+    rbuObjIterFinalize(&p->objiter);
+    sqlite3_close(p->dbRbu);
+    sqlite3_close(p->dbMain);
+    p->dbMain = 0;
+    p->dbRbu = 0;
+
+    dbMain = rbuOpenDbhandle(p, p->zTarget, 1);
+    if( dbMain ){
+      assert( p->rc==SQLITE_OK );
+      p->rc = rbuLockDatabase(dbMain);
+    }
+
    if( p->rc==SQLITE_OK ){
-      rbuFileSuffix3(zBase, zWal);
-      rbuFileSuffix3(zBase, zOal);
-
-      /* Re-open the databases. */
-      rbuObjIterFinalize(&p->objiter);
-      sqlite3_close(p->dbRbu);
-      sqlite3_close(p->dbMain);
-      p->dbMain = 0;
-      p->dbRbu = 0;
-
 #if defined(_WIN32_WCE)
      {
        LPWSTR zWideOal;
@@ -3232,11 +3267,19 @@ static void rbuMoveOalFile(sqlite3rbu *p){
 #else
      p->rc = rename(zOal, zWal) ? SQLITE_IOERR : SQLITE_OK;
 #endif
+    }

-      if( p->rc==SQLITE_OK ){
-        rbuOpenDatabase(p, 0);
-        rbuSetupCheckpoint(p, 0);
-      }
+    if( p->rc!=SQLITE_OK 
+     || rbuIsVacuum(p) 
+     || rbuExclusiveCheckpoint(dbMain)==0 
+    ){
+      sqlite3_close(dbMain);
+      dbMain = 0;
+    }
+
+    if( p->rc==SQLITE_OK ){
+      rbuOpenDatabase(p, dbMain, 0);
+      rbuSetupCheckpoint(p, 0);
    }
  }

@@ -3987,9 +4030,9 @@ static sqlite3rbu *openRbuHandle(
      ** If this is the case, it will have been checkpointed and deleted
      ** when the handle was closed and a second attempt to open the 
      ** database may succeed.  */
-      rbuOpenDatabase(p, &bRetry);
+      rbuOpenDatabase(p, 0, &bRetry);
      if( bRetry ){
-        rbuOpenDatabase(p, 0);
+        rbuOpenDatabase(p, 0, 0);
      }
    }

@@ -4084,6 +4127,14 @@ static sqlite3rbu *openRbuHandle(
      }else if( p->eStage==RBU_STAGE_MOVE ){
        /* no-op */
      }else if( p->eStage==RBU_STAGE_CKPT ){
+        if( !rbuIsVacuum(p) && rbuExclusiveCheckpoint(p->dbMain) ){
+          /* If the rbu_exclusive_checkpoint=1 URI parameter was specified
+          ** and an incremental checkpoint is being resumed, attempt an
+          ** exclusive lock on the db file. If this fails, so be it.  */
+          p->eStage = RBU_STAGE_DONE;
+          rbuLockDatabase(p->dbMain);
+          p->eStage = RBU_STAGE_CKPT;
+        }
        rbuSetupCheckpoint(p, pState);
      }else if( p->eStage==RBU_STAGE_DONE ){
        p->rc = SQLITE_DONE;
@@ -4121,7 +4172,6 @@ sqlite3rbu *sqlite3rbu_open(
  const char *zState
 ){
  if( zTarget==0 || zRbu==0 ){ return rbuMisuseError(); }
-  /* TODO: Check that zTarget and zRbu are non-NULL */
  return openRbuHandle(zTarget, zRbu, zState);
 }

@@ -4,7 +4,6 @@
 */
 #define TCLSH_INIT_PROC sqlite3_checker_init_proc
 #define SQLITE_ENABLE_DBPAGE_VTAB 1
-#define SQLITE_ENABLE_JSON1 1
 #undef SQLITE_THREADSAFE
 #define SQLITE_THREADSAFE 0
 #undef SQLITE_ENABLE_COLUMN_METADATA
@@ -26,11 +26,7 @@
 # define GEODEBUG(X)
 #endif

-#ifndef JSON_NULL   /* The following stuff repeats things found in json1 */
-/*
-** Versions of isspace(), isalnum() and isdigit() to which it is safe
-** to pass signed char values.
-*/
+/* Character class routines */
 #ifdef sqlite3Isdigit
   /* Use the SQLite core versions if this routine is part of the
   ** SQLite amalgamation */
@@ -45,6 +41,7 @@
 #  define safe_isxdigit(x) isxdigit((unsigned char)(x))
 #endif

+#ifndef JSON_NULL   /* The following stuff repeats things found in json1 */
 /*
 ** Growing our own isspace() routine this way is twice as fast as
 ** the library isspace() function.
@@ -67,7 +64,7 @@ static const char geopolyIsSpace[] = {
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
 };
-#define safe_isspace(x) (geopolyIsSpace[(unsigned char)x])
+#define fast_isspace(x) (geopolyIsSpace[(unsigned char)x])
 #endif /* JSON NULL - back to original code */

 /* Compiler and version */
@@ -156,7 +153,7 @@ static void geopolySwab32(unsigned char *a){

 /* Skip whitespace.  Return the next non-whitespace character. */
 static char geopolySkipSpace(GeoParse *p){
-  while( safe_isspace(p->z[0]) ) p->z++;
+  while( fast_isspace(p->z[0]) ) p->z++;
  return p->z[0];
 }

@@ -305,13 +302,14 @@ static GeoPoly *geopolyFuncParam(
 ){
  GeoPoly *p = 0;
  int nByte;
+  testcase( pCtx==0 );
  if( sqlite3_value_type(pVal)==SQLITE_BLOB
   && (nByte = sqlite3_value_bytes(pVal))>=(4+6*sizeof(GeoCoord))
  ){
    const unsigned char *a = sqlite3_value_blob(pVal);
    int nVertex;
    if( a==0 ){
-      sqlite3_result_error_nomem(pCtx);
+      if( pCtx ) sqlite3_result_error_nomem(pCtx);
      return 0;
    }
    nVertex = (a[1]<<16) + (a[2]<<8) + a[3];
@@ -1386,6 +1384,7 @@ static int geopolyFilter(
      RtreeCoord bbox[4];
      RtreeConstraint *p;
      assert( argc==1 );
+      assert( argv[0]!=0 );
      geopolyBBox(0, argv[0], bbox, &rc);
      if( rc ){
        goto geopoly_filter_end;
@@ -1613,6 +1612,7 @@ static int geopolyUpdate(
        || !sqlite3_value_nochange(aData[2])  /* UPDATE _shape */
        || oldRowid!=newRowid)                /* Rowid change */
  ){
+    assert( aData[2]!=0 );
    geopolyBBox(0, aData[2], cell.aCoord, &rc);
    if( rc ){
      if( rc==SQLITE_ERROR ){
@@ -1736,7 +1736,7 @@ static int geopolyFindFunction(


 static sqlite3_module geopolyModule = {
-  3,                          /* iVersion */
+  4,                          /* iVersion */
  geopolyCreate,              /* xCreate - create a table */
  geopolyConnect,             /* xConnect - connect to an existing table */
  geopolyBestIndex,           /* xBestIndex - Determine search strategy */
@@ -1759,7 +1759,8 @@ static sqlite3_module geopolyModule = {
  rtreeSavepoint,             /* xSavepoint */
  0,                          /* xRelease */
  0,                          /* xRollbackTo */
-  rtreeShadowName             /* xShadowName */
+  rtreeShadowName,            /* xShadowName */
+  rtreeShadowName2            /* xShadowName2 */
 };

 static int sqlite3_geopoly_init(sqlite3 *db){
@@ -436,7 +436,12 @@ struct RtreeMatchArg {
 ** it is not, make it a no-op.
 */
 #ifndef SQLITE_AMALGAMATION
-# define testcase(X)
+# if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+    unsigned int sqlite3RtreeTestcase = 0;
+#   define testcase(X)  if( X ){ sqlite3RtreeTestcase += __LINE__; }
+# else
+#   define testcase(X)
+# endif
 #endif

 /*
@@ -1282,20 +1287,29 @@ static void rtreeNonleafConstraint(
  switch( p->op ){
    case RTREE_TRUE:  return;   /* Always satisfied */
    case RTREE_FALSE: break;    /* Never satisfied */
-    case RTREE_LE:
-    case RTREE_LT:
    case RTREE_EQ:
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the lower bound of the coordinate pair */
+      if( p->u.rValue>=val ){
+        pCellData += 4;
+        RTREE_DECODE_COORD(eInt, pCellData, val);
+        /* val now holds the upper bound of the coordinate pair */
+        if( p->u.rValue<=val ) return;
+      }
+      break;
+    case RTREE_LE:
+    case RTREE_LT:
      RTREE_DECODE_COORD(eInt, pCellData, val);
      /* val now holds the lower bound of the coordinate pair */
      if( p->u.rValue>=val ) return;
-      if( p->op!=RTREE_EQ ) break;  /* RTREE_LE and RTREE_LT end here */
-      /* Fall through for the RTREE_EQ case */
+      break;

-    default: /* RTREE_GT or RTREE_GE,  or fallthrough of RTREE_EQ */
+    default:
      pCellData += 4;
      RTREE_DECODE_COORD(eInt, pCellData, val);
      /* val now holds the upper bound of the coordinate pair */
      if( p->u.rValue<=val ) return;
+      break;
  }
  *peWithin = NOT_WITHIN;
 }
@@ -2200,7 +2214,7 @@ static int ChooseLeaf(

    int nCell = NCELL(pNode);
    RtreeCell cell;
-    RtreeNode *pChild;
+    RtreeNode *pChild = 0;

    RtreeCell *aCell = 0;

@@ -2558,6 +2572,7 @@ static int updateMapping(
      pChild->pParent = pNode;
    }
  }
+  if( NEVER(pNode==0) ) return SQLITE_ERROR;
  return xSetMapping(pRtree, iRowid, pNode->iNode);
 }

@@ -3462,8 +3477,13 @@ static int rtreeShadowName(const char *zName){
  return 0;
 }

+static int rtreeShadowName2(sqlite3_vtab *pVtab, const char *zName){
+  UNUSED_PARAMETER(pVtab);
+  return rtreeShadowName(zName);
+}
+
 static sqlite3_module rtreeModule = {
-  3,                          /* iVersion */
+  4,                          /* iVersion */
  rtreeCreate,                /* xCreate - create a table */
  rtreeConnect,               /* xConnect - connect to an existing table */
  rtreeBestIndex,             /* xBestIndex - Determine search strategy */
@@ -3486,7 +3506,8 @@ static sqlite3_module rtreeModule = {
  rtreeSavepoint,             /* xSavepoint */
  0,                          /* xRelease */
  0,                          /* xRollbackTo */
-  rtreeShadowName             /* xShadowName */
+  rtreeShadowName,            /* xShadowName */
+  rtreeShadowName2            /* xShadowName2 */
 };

 static int rtreeSqlInit(
@@ -733,4 +733,27 @@ do_execsql_test 19.1 {
  SELECT v0.x FROM v0, rt0 WHERE v0.x = rt0.b;
 } {0.0}

+# 2022-06-20 https://sqlite.org/forum/forumpost/57bdf2217d
+#
+reset_db
+do_execsql_test 20.0 {
+  CREATE VIRTUAL TABLE rt0 USING rtree(id, x0, x1);
+  CREATE TABLE t0(a INT);
+  CREATE TABLE t1(b INT);
+  INSERT INTO rt0 VALUES(0, 0, 0);
+}
+do_catchsql_test 20.1 {
+  SELECT * FROM t1 JOIN t0 ON x0>a RIGHT JOIN rt0 ON true WHERE +x0 = 0;
+} {1 {ON clause references tables to its right}}
+do_catchsql_test 20.2 {
+  SELECT * FROM t1 JOIN t0 ON x0>a RIGHT JOIN rt0 ON true WHERE x0 = 0;
+} {1 {ON clause references tables to its right}}
+db null -
+do_execsql_test 20.3 {
+  SELECT * FROM t1 JOIN t0 ON true RIGHT JOIN rt0 ON x0>a WHERE +x0 = 0;
+} {- - 0 0.0 0.0}
+do_execsql_test 20.4 {
+  SELECT * FROM t1 JOIN t0 ON true RIGHT JOIN rt0 ON x0>a WHERE x0 = 0;
+} {- - 0 0.0 0.0}
+
 finish_test
@@ -23,6 +23,10 @@ ifcapable !rtree {
  return
 }

+set ::TMPDBERROR [list 1 \
+  {unable to open a temporary database file for storing temporary tables}
+]
+
 # Test summary:
 #
 #   rtree3-1: Test OOM in simple CREATE TABLE, INSERT, DELETE and SELECT 
@@ -196,9 +200,9 @@ do_test rtree3-7.prep {
 do_faultsim_test rtree3-7 -faults oom-* -prep {
  faultsim_restore_and_reopen
 } -body {
-  execsql { ALTER TABLE rt RENAME TO rt2 }
+  execsql { ALTER TABLE rt RENAME TO rt2 } 
 } -test {
-  faultsim_test_result {0 {}}
+  faultsim_test_result {0 {}} $::TMPDBERROR
 }

 do_faultsim_test rtree3-8 -faults oom-* -prep {
@@ -36,7 +36,7 @@ do_execsql_test rtree9-1.4 {
  DELETE FROM rt;
 } {}

-
+unset -nocomplain x
 for {set i 0} {$i < 1000} {incr i} {
  set x [expr $i%10]
  set y [expr ($i/10)%10]
@@ -165,7 +165,7 @@ do_corruption_tests rtreeA-3.1 {
 }

 do_execsql_test rtreeA-3.1.0.3 {
-  SELECT rtreecheck('main', 't1')!="ok"
+  SELECT rtreecheck('main', 't1')!='ok'
 } {1}

 do_test rtreeA-3.2.0 { set_tree_depth t1 1000 } {1000}
@@ -221,7 +221,7 @@ do_corruption_tests rtreeA-5.1 {
 }

 do_execsql_test rtreeA-5.2 {
-  SELECT rtreecheck('main', 't1')!="ok"
+  SELECT rtreecheck('main', 't1')!='ok'
 } {1}

 #-------------------------------------------------------------------------
@@ -238,7 +238,7 @@ do_corruption_tests rtreeA-6.1 {
 }

 do_execsql_test rtreeA-6.2 {
-  SELECT rtreecheck('main', 't1')!="ok"
+  SELECT rtreecheck('main', 't1')!='ok'
 } {1}

 #-------------------------------------------------------------------------
@@ -342,7 +342,7 @@ do_eqp_execsql_test 7.2 {
  QUERY PLAN
  |--SCAN xdir
  |--SCAN rt VIRTUAL TABLE INDEX 2:B0D1
-  `--SCAN ydir
+  `--SCAN ydir LEFT-JOIN
 } {
  5 1 2 7 12 14 {}
  5 2 2 7  8 12 10
@@ -117,13 +117,13 @@ sqlite3_db_config db DEFENSIVE 0
 do_execsql_test 3.2 {
  BEGIN;
    UPDATE r2_node SET data = X'123456';
-    SELECT rtreecheck('r2')!="ok";
+    SELECT rtreecheck('r2')!='ok';
 } {1}

 do_execsql_test 3.3 {
  ROLLBACK;
  UPDATE r2_node SET data = X'00001234';
-  SELECT rtreecheck('r2')!="ok";
+  SELECT rtreecheck('r2')!='ok';
 } {1}

 do_execsql_test 4.0 {
@@ -39,6 +39,7 @@ proc column_name_list {db tbl} {
  }
  return $lCol
 }
+unset -nocomplain res

 #-------------------------------------------------------------------------
 #-------------------------------------------------------------------------
@@ -792,6 +793,7 @@ do_execsql_test 3.0 {
  INSERT INTO x1 VALUES(4, 4, 4);
 }
 do_test 3.1 {
+  unset -nocomplain res
  set res [list]
  db eval { SELECT * FROM x1 } {
    lappend res $a $b $c
@@ -1579,4 +1581,3 @@ execsql ROLLBACK


 finish_test
-
--- a/Show More
+++ b/Show More
@@ -1 +1 @@
 .37.0
 .40.0