Change sqlite_blob_open() so that it zeros the output pBlob pointer when

it fails.  The other sqlite3_blob interfaces accept a NULL pointer as
input. (CVS 6622)

FossilOrigin-Name: 999d507b4432b518cfc7e02e5b0a2473cf1980f6

manifest

@@ -1,5 +1,5 @@
-C Changes\sto\sthe\strigger.c\smodule\sthat\sfacilitate\sfull\scoverage\stesting.\s(CVS\s6621)
+C Change\ssqlite_blob_open()\sso\sthat\sit\szeros\sthe\soutput\spBlob\spointer\swhen\nit\sfails.\s\sThe\sother\ssqlite3_blob\sinterfaces\saccept\sa\sNULL\spointer\sas\ninput.\s(CVS\s6622)
-D 2009-05-09T00:18:38
+D 2009-05-09T15:17:47
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -208,7 +208,7 @@ F src/vdbe.h 35a648bc3279a120da24f34d9a25213ec15daf8a
 F src/vdbeInt.h 43183a2a18654fa570219ab65e53a608057c48ae
 F src/vdbeapi.c 86aa27a5f3493aaffb8ac051782aa3b22670d7ed
 F src/vdbeaux.c 1a07329bdf51cc3687f88d9f5b2bd3f1d47cc5a8
-F src/vdbeblob.c e67757450ae8581a8b354d9d7e467e41502dfe38
+F src/vdbeblob.c 5c5abe9af28316772e7829359f6f9cda2c737ebd
 F src/vdbemem.c d8b985eeb88214941380372466a30ca410043a93
 F src/vtab.c 53355aa2381ec3ef2eaad25672cfd5877a02fe45
 F src/walker.c 7cdf63223c953d4343c6833e940f110281a378ee
@@ -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 254ca3273cfbd833de82296b4859e1ec5535e8be
+P 567ccc68cc8c73b952a91c71a0e00b08bb25c689
-R 29c312f4710fcc89e520e552563a8498
+R 886144e41731ebf2955c0b2ed8aed044
 U drh
-Z 4d4c05b89d8d2f3c2da064b74794e76b
+Z fabb4ba3bc1d6719d08d21dcbbdf7cee

manifest.uuid

@@ -1 +1 @@
-567ccc68cc8c73b952a91c71a0e00b08bb25c689
+999d507b4432b518cfc7e02e5b0a2473cf1980f6

src/vdbeblob.c

@@ -12,7 +12,7 @@
 **
 ** This file contains code used to implement incremental BLOB I/O.
 **
-** $Id: vdbeblob.c,v 1.31 2009/03/24 15:08:10 drh Exp $
+** $Id: vdbeblob.c,v 1.32 2009/05/09 15:17:47 drh Exp $
 */
 
 #include "sqliteInt.h"
@@ -85,6 +85,7 @@ int sqlite3_blob_open(
   int rc = SQLITE_OK;
   char zErr[128];
 
+  *ppBlob = 0;
   zErr[0] = 0;
   sqlite3_mutex_enter(db->mutex);
   do {
@@ -176,9 +177,10 @@ int sqlite3_blob_open(
       /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
       ** parameter of the other to pTab->tnum. 
       */
-      sqlite3VdbeChangeToNoop(v, (flags ? 2 : 3), 1);
+      flags = !!flags;
-      sqlite3VdbeChangeP2(v, (flags ? 3 : 2), pTab->tnum);
+      sqlite3VdbeChangeToNoop(v, 3 - flags, 1);
-      sqlite3VdbeChangeP3(v, (flags ? 3 : 2), iDb);
+      sqlite3VdbeChangeP2(v, 2 + flags, pTab->tnum);
+      sqlite3VdbeChangeP3(v, 2 + flags, iDb);
 
       /* Configure the number of columns. Configure the cursor to
       ** think that the table has one more column than it really
@@ -187,7 +189,7 @@ int sqlite3_blob_open(
       ** we can invoke OP_Column to fill in the vdbe cursors type 
       ** and offset cache without causing any IO.
       */
-      sqlite3VdbeChangeP4(v, flags ? 3 : 2, SQLITE_INT_TO_PTR(pTab->nCol+1), P4_INT32);
+      sqlite3VdbeChangeP4(v, 2+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
       sqlite3VdbeChangeP2(v, 6, pTab->nCol);
       if( !db->mallocFailed ){
         sqlite3VdbeMakeReady(v, 1, 1, 1, 0);
@@ -196,7 +198,7 @@ int sqlite3_blob_open(
    
     sqlite3BtreeLeaveAll(db);
     rc = sqlite3SafetyOff(db);
-    if( rc!=SQLITE_OK || db->mallocFailed ){
+    if( NEVER(rc!=SQLITE_OK) || db->mallocFailed ){
       goto blob_open_out;
     }
 
@@ -266,11 +268,15 @@ int sqlite3_blob_close(sqlite3_blob *pBlob){
   int rc;
   sqlite3 *db;
 
-  db = p->db;
+  if( p ){
-  sqlite3_mutex_enter(db->mutex);
+    db = p->db;
-  rc = sqlite3_finalize(p->pStmt);
+    sqlite3_mutex_enter(db->mutex);
-  sqlite3DbFree(db, p);
+    rc = sqlite3_finalize(p->pStmt);
-  sqlite3_mutex_leave(db->mutex);
+    sqlite3DbFree(db, p);
+    sqlite3_mutex_leave(db->mutex);
+  }else{
+    rc = SQLITE_OK;
+  }
   return rc;
 }
 
@@ -287,8 +293,10 @@ static int blobReadWrite(
   int rc;
   Incrblob *p = (Incrblob *)pBlob;
   Vdbe *v;
-  sqlite3 *db = p->db;  
+  sqlite3 *db;
 
+  if( p==0 ) return SQLITE_MISUSE;
+  db = p->db;
   sqlite3_mutex_enter(db->mutex);
   v = (Vdbe*)p->pStmt;
 
@@ -344,7 +352,7 @@ int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int iOffset){
 */
 int sqlite3_blob_bytes(sqlite3_blob *pBlob){
   Incrblob *p = (Incrblob *)pBlob;
-  return p->nByte;
+  return p ? p->nByte : 0;
 }
 
 #endif /* #ifndef SQLITE_OMIT_INCRBLOB */