Convert the hint expression of the CursorHint opcode into a string for

display by EXPLAIN.

FossilOrigin-Name: 12640cb22240ee436cad99360ceb9a208edd14f5

manifest

@@ -1,5 +1,5 @@
-C Add\ssimple\stests\sfor\snew\ssqlite3BtreeCursorHint()\sfunctionality.
-D 2014-07-15T11:59:44.612
+C Convert\sthe\shint\sexpression\sof\sthe\sCursorHint\sopcode\sinto\sa\sstring\sfor\ndisplay\sby\sEXPLAIN.
+D 2015-08-13T21:43:19.244
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in e1a9b4258bbde53f5636f4e238c65b7e11459e2b
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -283,9 +283,9 @@ F src/util.c 76ed0519296e3f62e97e57dab1999e34184c8e49
 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
 F src/vdbe.c 54e269c6268a6f37697e27d6bc572674f14b1581
 F src/vdbe.h 57b87844270b2e92647b8b82a8948f7a29efae8d
-F src/vdbeInt.h 05fbda0e061dbc4aaa2709a8cccf3515c245b263
+F src/vdbeInt.h 9ad955ca89d4dc4b6056cece1896b4b85a8521fe
 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed
-F src/vdbeaux.c c7c9219cb31cef9917db3b3b41604ac74c5bc41b
+F src/vdbeaux.c f4ed66c45336e42e7f1bdaccf7586c84eba06bac
 F src/vdbeblob.c 8cd05a5630e6d5563ad017bf82edaf812b28acde
 F src/vdbemem.c 20e349d2ca928802fc8f2d42a2cc488fd6981d3f
 F src/vdbesort.c 9d83601f9d6243fe70dd0169a2820c5ddfd48147
@@ -1148,7 +1148,11 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P f9dddd008c6ef7940a1d66363fbb456cff7207c1
-R 9fb1051a18f0e187efee634c86c45e62
-U dan
-Z 04e07c13931dc702da8721e6980ca969
+P 1efa6ed584172291edce78faf9021e577583d03b
+Q +206884718782331a7aaacc2c811e4e9d2effae91
+R fcae2238c266b3818e83c96b2fcbbede
+T *branch * cursor-hints-displayP4
+T *sym-cursor-hints-displayP4 *
+T -sym-cursor-hints *
+U drh
+Z 41561b125b2ba8dcbfb094780611e534

manifest.uuid

@@ -1 +1 @@
-1efa6ed584172291edce78faf9021e577583d03b
+12640cb22240ee436cad99360ceb9a208edd14f5

src/vdbeInt.h

@@ -26,6 +26,17 @@
 # define SQLITE_MAX_SCHEMA_RETRY 50
 #endif
 
+/*
+** VDBE_DISPLAY_P4 is true or false depending on whether or not the
+** "explain" P4 display logic is enabled.
+*/
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+# define VDBE_DISPLAY_P4 1
+#else
+# define VDBE_DISPLAY_P4 0
+#endif
+
 /*
 ** SQL is translated into a sequence of instructions to be
 ** executed by a virtual machine.  Each instruction is an instance

src/vdbeaux.c

@@ -947,9 +947,78 @@ static int displayComment(
 }
 #endif /* SQLITE_DEBUG */
 
+#if VDBE_DISPLAY_P4 && defined(SQLITE_ENABLE_CURSOR_HINTS)
+/*
+** Translate the P4.pExpr value for an OP_CursorHint opcode into text
+** that can be displayed in the P4 column of EXPLAIN output.
+*/
+static int displayP4Expr(int nTemp, char *zTemp, Expr *pExpr){
+  const char *zBinOp = 0;
+  switch( pExpr->op ){
+    case TK_STRING:
+      sqlite3_snprintf(nTemp, zTemp, "%Q", pExpr->u.zToken);
+      break;
 
-#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
-     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+    case TK_INTEGER:
+      sqlite3_snprintf(nTemp, zTemp, "%d", pExpr->u.iValue);
+      break;
+
+    case TK_NULL:
+      sqlite3_snprintf(nTemp, zTemp, "NULL");
+      break;
+
+    case TK_REGISTER: {
+      sqlite3_snprintf(nTemp, zTemp, "r[%d]", pExpr->iTable);
+      break;
+    }
+
+    case TK_COLUMN: {
+      sqlite3_snprintf(nTemp, zTemp, "c%d", (int)pExpr->iColumn);
+      break;
+    }
+
+    case TK_LT:      zBinOp = "<";        break;
+    case TK_LE:      zBinOp = "<=";       break;
+    case TK_GT:      zBinOp = ">";        break;
+    case TK_GE:      zBinOp = ">=";       break;
+    case TK_NE:      zBinOp = "!=";       break;
+    case TK_EQ:      zBinOp = "==";       break;
+    case TK_IS:      zBinOp = " IS ";     break;
+    case TK_ISNOT:   zBinOp = " IS NOT "; break;
+    case TK_AND:     zBinOp = " AND ";    break;
+    case TK_OR:      zBinOp = " OR ";     break;
+    case TK_PLUS:    zBinOp = "+";        break;
+    case TK_STAR:    zBinOp = "*";        break;
+    case TK_MINUS:   zBinOp = "-";        break;
+    case TK_REM:     zBinOp = "%";        break;
+    case TK_BITAND:  zBinOp = "&";        break;
+    case TK_BITOR:   zBinOp = "|";        break;
+    case TK_SLASH:   zBinOp = "/";        break;
+    case TK_LSHIFT:  zBinOp = "<<";       break;
+    case TK_RSHIFT:  zBinOp = ">>";       break;
+    case TK_CONCAT:  zBinOp = "||";       break;
+
+    default:
+      sqlite3_snprintf(nTemp, zTemp, "%s", "expr");
+      break;
+  }
+
+  if( zBinOp && nTemp>5 ){
+    int n = 1;
+    zTemp[0] = '(';
+    n += displayP4Expr(nTemp-n, zTemp+n, pExpr->pLeft);
+    sqlite3_snprintf(nTemp-n, zTemp+n, "%s", zBinOp);
+    n += sqlite3Strlen30(zTemp+n);
+    n += displayP4Expr(nTemp-n, zTemp+n, pExpr->pRight);
+    sqlite3_snprintf(nTemp-n, zTemp+n, ")");
+  }
+
+  return sqlite3Strlen30(zTemp);
+}
+#endif /* VDBE_DISPLAY_P4 && defined(SQLITE_ENABLE_CURSOR_HINTS) */
+
+
+#if VDBE_DISPLAY_P4
 /*
 ** Compute a string that describes the P4 parameter for an opcode.
 ** Use zTemp for any required temporary buffer space.
@@ -990,7 +1059,7 @@ static char *displayP4(Op *pOp, char *zTemp, int nTemp){
     }
 #ifdef SQLITE_ENABLE_CURSOR_HINTS
     case P4_EXPR: {
-      sqlite3_snprintf(nTemp, zTemp, "(expr)");
+      displayP4Expr(nTemp, zTemp, pOp->p4.pExpr);
       break;
     }
 #endif
@@ -1062,7 +1131,7 @@ static char *displayP4(Op *pOp, char *zTemp, int nTemp){
   assert( zP4!=0 );
   return zP4;
 }
-#endif
+#endif /* VDBE_DISPLAY_P4 */
 
 /*
 ** Declare to the Vdbe that the BTree object at db->aDb[i] is used.