Change the sqlite3_backup_finish() interface so that calling it with

a NULL pointer is a harmless no-op.  One other change to backup.c to facilitate
full coverage testing. (CVS 6638)

FossilOrigin-Name: 06bc89177b3af20751d9567a68551d2d31c3fe8b

manifest

@@ -1,5 +1,5 @@
-C Documentation\supdates\sto\sbetter\sexplain\sthe\sSQLITE_OPEN_EXCLUSIVE\sflag.\s\sTicket\s#3855.\s(CVS\s6637)
-D 2009-05-14T03:21:28
+C Change\sthe\ssqlite3_backup_finish()\sinterface\sso\sthat\scalling\sit\swith\na\sNULL\spointer\sis\sa\sharmless\sno-op.\s\sOne\sother\schange\sto\sbackup.c\sto\sfacilitate\nfull\scoverage\stesting.\s(CVS\s6638)
+D 2009-05-14T19:26:51
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -103,7 +103,7 @@ F src/alter.c f0430ee68d8d80711155ddf27876abf218903b03
 F src/analyze.c e239496cfb5394ac8867f1c112905ddab8d01cd9
 F src/attach.c 3b99611f04926fc69c35b1145603fc3ddb0ca967
 F src/auth.c 98db07c2088455797678eb1031f42d4d94d18a71
-F src/backup.c 91aaf9f065b923f33d8739f44f71ab8d9226a8d1
+F src/backup.c 437efc2c3371b52bbb943b8c9dfabba774adcf86
 F src/bitvec.c ef370407e03440b0852d05024fb016b14a471d3d
 F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
 F src/btree.c 7c4b02afea7efb561361f20408414fec68df898c
@@ -729,7 +729,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 913d11149396d3dc797f1efeb4f7e60865483399
-R abb9e0125d369edd65ceec50369d192a
-U shane
-Z 0b4778e326f1addd073ef44654a5d985
+P 6bd44f36f46810eb9ce30c7780de6bcfe4aadf5f
+R 08294acfb06e382228ced064d7f97ab0
+U drh
+Z f08fef6da3e6dfcb1865b029ed85932c

manifest.uuid

@@ -1 +1 @@
-6bd44f36f46810eb9ce30c7780de6bcfe4aadf5f
+06bc89177b3af20751d9567a68551d2d31c3fe8b

src/backup.c

@@ -12,7 +12,7 @@
 ** This file contains the implementation of the sqlite3_backup_XXX() 
 ** API functions and the related features.
 **
-** $Id: backup.c,v 1.14 2009/05/13 07:52:06 danielk1977 Exp $
+** $Id: backup.c,v 1.15 2009/05/14 19:26:51 drh Exp $
 */
 #include "sqliteInt.h"
 #include "btreeInt.h"
@@ -184,7 +184,7 @@ sqlite3_backup *sqlite3_backup_init(
 ** are considered fatal except for SQLITE_BUSY and SQLITE_LOCKED.
 */
 static int isFatalError(int rc){
-  return (rc!=SQLITE_OK && rc!=SQLITE_BUSY && rc!=SQLITE_LOCKED);
+  return (rc!=SQLITE_OK && rc!=SQLITE_BUSY && ALWAYS(rc!=SQLITE_LOCKED));
 }
 
 /*
@@ -469,6 +469,7 @@ int sqlite3_backup_finish(sqlite3_backup *p){
   int rc;                              /* Value to return */
 
   /* Enter the mutexes */
+  if( p==0 ) return SQLITE_OK;
   sqlite3_mutex_enter(p->pSrcDb->mutex);
   sqlite3BtreeEnter(p->pSrc);
   mutex = p->pSrcDb->mutex;