diff -r 5f8e5adbbed9 -r 29cda98b007e engine/sqlite/src/mem2.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/sqlite/src/mem2.cpp	Thu Feb 25 14:29:19 2010 +0000
@@ -0,0 +1,573 @@
+/*
+** 2007 August 15
+**
+** 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 the C functions that implement a memory
+** allocation subsystem for use by SQLite.  
+**
+** $Id: mem2.cpp 1282 2008-11-13 09:31:33Z LarsPson $
+*/
+
+/*
+** This version of the memory allocator is used only if the
+** SQLITE_MEMDEBUG macro is defined and SQLITE_OMIT_MEMORY_ALLOCATION
+** is not defined.
+*/
+#if defined(SQLITE_MEMDEBUG)
+
+/*
+** We will eventually construct multiple memory allocation subsystems
+** suitable for use in various contexts:
+**
+**    *  Normal multi-threaded builds
+**    *  Normal single-threaded builds
+**    *  Debugging builds
+**
+** This version is suitable for use in debugging builds.
+**
+** Features:
+**
+**    * Every allocate has guards at both ends.
+**    * New allocations are initialized with randomness
+**    * Allocations are overwritten with randomness when freed
+**    * Optional logs of malloc activity generated
+**    * Summary of outstanding allocations with backtraces to the
+**      point of allocation.
+**    * The ability to simulate memory allocation failure
+*/
+#include "sqliteInt.h"
+#include <stdio.h>
+
+/*
+** The backtrace functionality is only available with GLIBC
+*/
+#ifdef __GLIBC__
+  extern int backtrace(void**,int);
+  extern void backtrace_symbols_fd(void*const*,int,int);
+#else
+# define backtrace(A,B) 0
+# define backtrace_symbols_fd(A,B,C)
+#endif
+
+/*
+** Each memory allocation looks like this:
+**
+**  ------------------------------------------------------------------------
+**  | Title |  backtrace pointers |  MemBlockHdr |  allocation |  EndGuard |
+**  ------------------------------------------------------------------------
+**
+** The application code sees only a pointer to the allocation.  We have
+** to back up from the allocation pointer to find the MemBlockHdr.  The
+** MemBlockHdr tells us the size of the allocation and the number of
+** backtrace pointers.  There is also a guard word at the end of the
+** MemBlockHdr.
+*/
+struct MemBlockHdr {
+  struct MemBlockHdr *pNext, *pPrev;  /* Linked list of all unfreed memory */
+  int iSize;                          /* Size of this allocation */
+  char nBacktrace;                    /* Number of backtraces on this alloc */
+  char nBacktraceSlots;               /* Available backtrace slots */
+  short nTitle;                       /* Bytes of title; includes '\0' */
+  int iForeGuard;                     /* Guard word for sanity */
+};
+
+/*
+** Guard words
+*/
+#define FOREGUARD 0x80F5E153
+#define REARGUARD 0xE4676B53
+
+/*
+** Number of malloc size increments to track.
+*/
+#define NCSIZE  1000
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+  /*
+  ** The alarm callback and its arguments.  The mem.mutex lock will
+  ** be held while the callback is running.  Recursive calls into
+  ** the memory subsystem are allowed, but no new callbacks will be
+  ** issued.  The alarmBusy variable is set to prevent recursive
+  ** callbacks.
+  */
+  sqlite3_int64 alarmThreshold;
+  void (*alarmCallback)(void*, sqlite3_int64, int);
+  void *alarmArg;
+  int alarmBusy;
+  
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+  
+  /*
+  ** Current allocation and high-water mark.
+  */
+  sqlite3_int64 nowUsed;
+  sqlite3_int64 mxUsed;
+  
+  /*
+  ** Head and tail of a linked list of all outstanding allocations
+  */
+  struct MemBlockHdr *pFirst;
+  struct MemBlockHdr *pLast;
+  
+  /*
+  ** The number of levels of backtrace to save in new allocations.
+  */
+  int nBacktrace;
+
+  /*
+  ** Title text to insert in front of each block
+  */
+  int nTitle;        /* Bytes of zTitle to save.  Includes '\0' and padding */
+  char zTitle[100];  /* The title text */
+
+  /*
+  ** These values are used to simulate malloc failures.  When
+  ** iFail is 1, simulate a malloc failures and reset the value
+  ** to iReset.
+  */
+  int iFail;    /* Decrement and fail malloc when this is 1 */
+  int iReset;   /* When malloc fails set iiFail to this value */
+  int iFailCnt;         /* Number of failures */
+  int iBenignFailCnt;   /* Number of benign failures */
+  int iNextIsBenign;    /* True if the next call to malloc may fail benignly */
+  int iIsBenign;        /* All malloc calls may fail benignly */
+
+  /* 
+  ** sqlite3MallocDisallow() increments the following counter.
+  ** sqlite3MallocAllow() decrements it.
+  */
+  int disallow; /* Do not allow memory allocation */
+
+  /*
+  ** Gather statistics on the sizes of memory allocations.
+  ** sizeCnt[i] is the number of allocation attempts of i*8
+  ** bytes.  i==NCSIZE is the number of allocation attempts for
+  ** sizes more than NCSIZE*8 bytes.
+  */
+  int sizeCnt[NCSIZE];
+
+} mem;
+
+
+/*
+** Enter the mutex mem.mutex. Allocate it if it is not already allocated.
+*/
+static void enterMem(void){
+  if( mem.mutex==0 ){
+    mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  sqlite3_mutex_enter(mem.mutex);
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.nowUsed;
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 n;
+  enterMem();
+  n = mem.mxUsed;
+  if( resetFlag ){
+    mem.mxUsed = mem.nowUsed;
+  }
+  sqlite3_mutex_leave(mem.mutex);  
+  return n;
+}
+
+/*
+** Change the alarm callback
+*/
+int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used, int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  enterMem();
+  mem.alarmCallback = xCallback;
+  mem.alarmArg = pArg;
+  mem.alarmThreshold = iThreshold;
+  sqlite3_mutex_leave(mem.mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Trigger the alarm 
+*/
+static void sqlite3MemsysAlarm(int nByte){
+  void (*xCallback)(void*,sqlite3_int64,int);
+  sqlite3_int64 nowUsed;
+  void *pArg;
+  if( mem.alarmCallback==0 || mem.alarmBusy  ) return;
+  mem.alarmBusy = 1;
+  xCallback = mem.alarmCallback;
+  nowUsed = mem.nowUsed;
+  pArg = mem.alarmArg;
+  sqlite3_mutex_leave(mem.mutex);
+  xCallback(pArg, nowUsed, nByte);
+  sqlite3_mutex_enter(mem.mutex);
+  mem.alarmBusy = 0;
+}
+
+/*
+** Given an allocation, find the MemBlockHdr for that allocation.
+**
+** This routine checks the guards at either end of the allocation and
+** if they are incorrect it asserts.
+*/
+static struct MemBlockHdr *sqlite3MemsysGetHeader(void *pAllocation){
+  struct MemBlockHdr *p;
+  int *pInt;
+
+  p = (struct MemBlockHdr*)pAllocation;
+  p--;
+  assert( p->iForeGuard==FOREGUARD );
+  assert( (p->iSize & 3)==0 );
+  pInt = (int*)pAllocation;
+  assert( pInt[p->iSize/sizeof(int)]==REARGUARD );
+  return p;
+}
+
+/*
+** This routine is called once the first time a simulated memory
+** failure occurs.  The sole purpose of this routine is to provide
+** a convenient place to set a debugger breakpoint when debugging
+** errors related to malloc() failures.
+*/
+static void sqlite3MemsysFailed(void){
+  mem.iFailCnt = 0;
+  mem.iBenignFailCnt = 0;
+}
+
+/*
+** Allocate nByte bytes of memory.
+*/
+void *sqlite3_malloc(int nByte){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  int *pInt;
+  void *p = 0;
+  int totalSize;
+
+  if( nByte>0 ){
+    enterMem();
+    assert( mem.disallow==0 );
+    if( mem.alarmCallback!=0 && mem.nowUsed+nByte>=mem.alarmThreshold ){
+      sqlite3MemsysAlarm(nByte);
+    }
+    nByte = (nByte+3)&~3;
+    if( nByte/8>NCSIZE-1 ){
+      mem.sizeCnt[NCSIZE-1]++;
+    }else{
+      mem.sizeCnt[nByte/8]++;
+    }
+    totalSize = nByte + sizeof(*pHdr) + sizeof(int) +
+                 mem.nBacktrace*sizeof(void*) + mem.nTitle;
+    if( mem.iFail>0 ){
+      if( mem.iFail==1 ){
+        p = 0;
+        mem.iFail = mem.iReset;
+        if( mem.iFailCnt==0 ){
+          sqlite3MemsysFailed();  /* A place to set a breakpoint */
+        }
+        mem.iFailCnt++;
+        if( mem.iNextIsBenign || mem.iIsBenign ){
+          mem.iBenignFailCnt++;
+        }
+      }else{
+        p = malloc(totalSize);
+        mem.iFail--;
+      }
+    }else{
+      p = malloc(totalSize);
+      if( p==0 ){
+        sqlite3MemsysAlarm(nByte);
+        p = malloc(totalSize);
+      }
+    }
+    if( p ){
+      z = p;
+      pBt = (void**)&z[mem.nTitle];
+      pHdr = (struct MemBlockHdr*)&pBt[mem.nBacktrace];
+      pHdr->pNext = 0;
+      pHdr->pPrev = mem.pLast;
+      if( mem.pLast ){
+        mem.pLast->pNext = pHdr;
+      }else{
+        mem.pFirst = pHdr;
+      }
+      mem.pLast = pHdr;
+      pHdr->iForeGuard = FOREGUARD;
+      pHdr->nBacktraceSlots = mem.nBacktrace;
+      pHdr->nTitle = mem.nTitle;
+      if( mem.nBacktrace ){
+        void *aAddr[40];
+        pHdr->nBacktrace = backtrace(aAddr, mem.nBacktrace+1)-1;
+        memcpy(pBt, &aAddr[1], pHdr->nBacktrace*sizeof(void*));
+      }else{
+        pHdr->nBacktrace = 0;
+      }
+      if( mem.nTitle ){
+        memcpy(z, mem.zTitle, mem.nTitle);
+      }
+      pHdr->iSize = nByte;
+      pInt = (int*)&pHdr[1];
+      pInt[nByte/sizeof(int)] = REARGUARD;
+      memset(pInt, 0x65, nByte);
+      mem.nowUsed += nByte;
+      if( mem.nowUsed>mem.mxUsed ){
+        mem.mxUsed = mem.nowUsed;
+      }
+      p = (void*)pInt;
+    }
+    sqlite3_mutex_leave(mem.mutex);
+  }
+  mem.iNextIsBenign = 0;
+  return p; 
+}
+
+/*
+** Free memory.
+*/
+void sqlite3_free(void *pPrior){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  if( pPrior==0 ){
+    return;
+  }
+  assert( mem.mutex!=0 );
+  pHdr = sqlite3MemsysGetHeader(pPrior);
+  pBt = (void**)pHdr;
+  pBt -= pHdr->nBacktraceSlots;
+  sqlite3_mutex_enter(mem.mutex);
+  mem.nowUsed -= pHdr->iSize;
+  if( pHdr->pPrev ){
+    assert( pHdr->pPrev->pNext==pHdr );
+    pHdr->pPrev->pNext = pHdr->pNext;
+  }else{
+    assert( mem.pFirst==pHdr );
+    mem.pFirst = pHdr->pNext;
+  }
+  if( pHdr->pNext ){
+    assert( pHdr->pNext->pPrev==pHdr );
+    pHdr->pNext->pPrev = pHdr->pPrev;
+  }else{
+    assert( mem.pLast==pHdr );
+    mem.pLast = pHdr->pPrev;
+  }
+  z = (char*)pBt;
+  z -= pHdr->nTitle;
+  memset(z, 0x2b, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
+                  pHdr->iSize + sizeof(int) + pHdr->nTitle);
+  free(z);
+  sqlite3_mutex_leave(mem.mutex);  
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** For this debugging implementation, we *always* make a copy of the
+** allocation into a new place in memory.  In this way, if the 
+** higher level code is using pointer to the old allocation, it is 
+** much more likely to break and we are much more liking to find
+** the error.
+*/
+void *sqlite3_realloc(void *pPrior, int nByte){
+  struct MemBlockHdr *pOldHdr;
+  void *pNew;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nByte);
+  }
+  if( nByte<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  assert( mem.disallow==0 );
+  pOldHdr = sqlite3MemsysGetHeader(pPrior);
+  pNew = sqlite3_malloc(nByte);
+  if( pNew ){
+    memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
+    if( nByte>pOldHdr->iSize ){
+      memset(&((char*)pNew)[pOldHdr->iSize], 0x2b, nByte - pOldHdr->iSize);
+    }
+    sqlite3_free(pPrior);
+  }
+  return pNew;
+}
+
+/*
+** Set the number of backtrace levels kept for each allocation.
+** A value of zero turns of backtracing.  The number is always rounded
+** up to a multiple of 2.
+*/
+void sqlite3_memdebug_backtrace(int depth){
+  if( depth<0 ){ depth = 0; }
+  if( depth>20 ){ depth = 20; }
+  depth = (depth+1)&0xfe;
+  mem.nBacktrace = depth;
+}
+
+/*
+** Set the title string for subsequent allocations.
+*/
+void sqlite3_memdebug_settitle(const char *zTitle){
+  int n = strlen(zTitle) + 1;
+  enterMem();
+  if( n>=sizeof(mem.zTitle) ) n = sizeof(mem.zTitle)-1;
+  memcpy(mem.zTitle, zTitle, n);
+  mem.zTitle[n] = 0;
+  mem.nTitle = (n+3)&~3;
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory 
+** allocations into that log.
+*/
+void sqlite3_memdebug_dump(const char *zFilename){
+  FILE *out;
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  int i;
+  out = fopen(zFilename, "w");
+  if( out==0 ){
+    fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                    zFilename);
+    return;
+  }
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    char *z = (char*)pHdr;
+    z -= pHdr->nBacktraceSlots*sizeof(void*) + pHdr->nTitle;
+    fprintf(out, "**** %d bytes at %p from %s ****\n", 
+            pHdr->iSize, &pHdr[1], pHdr->nTitle ? z : "???");
+    if( pHdr->nBacktrace ){
+      fflush(out);
+      pBt = (void**)pHdr;
+      pBt -= pHdr->nBacktraceSlots;
+      backtrace_symbols_fd(pBt, pHdr->nBacktrace, fileno(out));
+      fprintf(out, "\n");
+    }
+  }
+  fprintf(out, "COUNTS:\n");
+  for(i=0; i<NCSIZE-1; i++){
+    if( mem.sizeCnt[i] ){
+      fprintf(out, "   %3d: %d\n", i*8+8, mem.sizeCnt[i]);
+    }
+  }
+  if( mem.sizeCnt[NCSIZE-1] ){
+    fprintf(out, "  >%3d: %d\n", NCSIZE*8, mem.sizeCnt[NCSIZE-1]);
+  }
+  fclose(out);
+}
+
+/*
+** This routine is used to simulate malloc failures.
+**
+** After calling this routine, there will be iFail successful
+** memory allocations and then a failure.  If iRepeat is 1
+** all subsequent memory allocations will fail.  If iRepeat is
+** 0, only a single allocation will fail.  If iRepeat is negative
+** then the previous setting for iRepeat is unchanged.
+**
+** Each call to this routine overrides the previous.  To disable
+** the simulated allocation failure mechanism, set iFail to -1.
+**
+** This routine returns the number of simulated failures that have
+** occurred since the previous call.
+*/
+int sqlite3_memdebug_fail(int iFail, int iRepeat, int *piBenign){
+  int n = mem.iFailCnt;
+  if( piBenign ){
+    *piBenign = mem.iBenignFailCnt;
+  }
+  mem.iFail = iFail+1;
+  if( iRepeat>=0 ){
+    mem.iReset = iRepeat;
+  }
+  mem.iFailCnt = 0;
+  mem.iBenignFailCnt = 0;
+  return n;
+}
+
+int sqlite3_memdebug_pending(){
+  return (mem.iFail-1);
+}
+
+/*
+** The following three functions are used to indicate to the test 
+** infrastructure which malloc() calls may fail benignly without
+** affecting functionality. This can happen when resizing hash tables 
+** (failing to resize a hash-table is a performance hit, but not an 
+** error) or sometimes during a rollback operation.
+**
+** If the argument is true, sqlite3MallocBenignFailure() indicates that the
+** next call to allocate memory may fail benignly.
+**
+** If sqlite3MallocEnterBenignBlock() is called with a non-zero argument,
+** then all memory allocations requested before the next call to
+** sqlite3MallocLeaveBenignBlock() may fail benignly.
+*/
+void sqlite3MallocBenignFailure(int isBenign){
+  if( isBenign ){
+    mem.iNextIsBenign = 1;
+  }
+}
+void sqlite3MallocEnterBenignBlock(int isBenign){
+  if( isBenign ){
+    mem.iIsBenign = 1;
+  }
+}
+void sqlite3MallocLeaveBenignBlock(){
+  mem.iIsBenign = 0;
+}
+
+/*
+** The following two routines are used to assert that no memory
+** allocations occur between one call and the next.  The use of
+** these routines does not change the computed results in any way.
+** These routines are like asserts.
+*/
+void sqlite3MallocDisallow(void){
+  assert( mem.mutex!=0 );
+  sqlite3_mutex_enter(mem.mutex);
+  mem.disallow++;
+  sqlite3_mutex_leave(mem.mutex);
+}
+void sqlite3MallocAllow(void){
+  assert( mem.mutex );
+  sqlite3_mutex_enter(mem.mutex);
+  assert( mem.disallow>0 );
+  mem.disallow--;
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+#endif /* SQLITE_MEMDEBUG && !SQLITE_OMIT_MEMORY_ALLOCATION */