Add the ability to simulate out-of-memory errors when using the default

memory allocator, mem1.c.  Fix a bug that this enhancement revealed. (CVS 4875)

FossilOrigin-Name: d55a5e1c11ef90534abd2e5f18d06dd4739ade70

3 files changed, 24 insertions, 19 deletions

diff --git a/src/mem1.c b/src/mem1.c
index 2b28a8cdb..87dd41afc 100644
--- a/src/mem1.c
+++ b/src/mem1.c
@@ -12,7 +12,7 @@
 ** This file contains the C functions that implement a memory
 ** allocation subsystem for use by SQLite.  
 **
-** $Id: mem1.c,v 1.16 2008/02/14 23:26:56 drh Exp $
+** $Id: mem1.c,v 1.17 2008/03/18 00:07:11 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -137,10 +137,14 @@ void *sqlite3_malloc(int nBytes){
     if( mem.alarmCallback!=0 && mem.nowUsed+nBytes>=mem.alarmThreshold ){
       sqlite3MemsysAlarm(nBytes);
     }
-    p = malloc(nBytes+8);
-    if( p==0 ){
-      sqlite3MemsysAlarm(nBytes);
+    if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
+      p = 0;
+    }else{
       p = malloc(nBytes+8);
+      if( p==0 ){
+        sqlite3MemsysAlarm(nBytes);
+        p = malloc(nBytes+8);
+      }
     }
     if( p ){
       p[0] = nBytes;
@@ -205,12 +209,16 @@ void *sqlite3_realloc(void *pPrior, int nBytes){
   if( mem.nowUsed+nBytes-nOld>=mem.alarmThreshold ){
     sqlite3MemsysAlarm(nBytes-nOld);
   }
-  p = realloc(p, nBytes+8);
-  if( p==0 ){
-    sqlite3MemsysAlarm(nBytes);
-    p = pPrior;
-    p--;
+  if( sqlite3FaultStep(SQLITE_FAULTINJECTOR_MALLOC) ){
+    p = 0;
+  }else{
     p = realloc(p, nBytes+8);
+    if( p==0 ){
+      sqlite3MemsysAlarm(nBytes);
+      p = pPrior;
+      p--;
+      p = realloc(p, nBytes+8);
+    }
   }
   if( p ){
     p[0] = nBytes;
diff --git a/src/test_malloc.c b/src/test_malloc.c
index 86a32059f..38708009a 100644
--- a/src/test_malloc.c
+++ b/src/test_malloc.c
@@ -13,7 +13,7 @@
 ** This file contains code used to implement test interfaces to the
 ** memory allocation subsystem.
 **
-** $Id: test_malloc.c,v 1.15 2008/02/19 15:15:16 drh Exp $
+** $Id: test_malloc.c,v 1.16 2008/03/18 00:07:11 drh Exp $
 */
 #include "sqliteInt.h"
 #include "tcl.h"
@@ -463,18 +463,14 @@ static int test_memdebug_pending(
   int objc,
   Tcl_Obj *CONST objv[]
 ){
+  int nPending;
   if( objc!=1 ){
     Tcl_WrongNumArgs(interp, 1, objv, "");
     return TCL_ERROR;
   }
-
-#if defined(SQLITE_MEMDEBUG) || defined(SQLITE_POW2_MEMORY_SIZE)
-  {
-    int nPending = sqlite3_test_control(SQLITE_TESTCTRL_FAULT_PENDING,
-                                        SQLITE_FAULTINJECTOR_MALLOC);
-    Tcl_SetObjResult(interp, Tcl_NewIntObj(nPending));
-  }
-#endif
+  nPending = sqlite3_test_control(SQLITE_TESTCTRL_FAULT_PENDING,
+                                  SQLITE_FAULTINJECTOR_MALLOC);
+  Tcl_SetObjResult(interp, Tcl_NewIntObj(nPending));
   return TCL_OK;
 }
 
diff --git a/src/vdbemem.c b/src/vdbemem.c
index 632151c19..1c72cb37a 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -81,7 +81,7 @@ int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve){
        || (f & (MEM_Dyn|MEM_Static|MEM_Ephem))==MEM_Static 
   );
 
-  if( ((f&MEM_Dyn)==0 || pMem->xDel || sqlite3MallocSize(pMem->z)<n) ){
+  if( (f&MEM_Dyn)==0 || pMem->xDel || sqlite3MallocSize(pMem->z)<n ){
 
     /* Allocate the new buffer. The minimum allocation size is 32 bytes. */
     char *z = 0;
@@ -94,6 +94,7 @@ int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve){
         z = sqlite3DbMallocRaw(pMem->db, (n>32?n:32));
       }
       if( !z ){
+        pMem->flags = MEM_Null;
         return SQLITE_NOMEM;
       }
     }