--- /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 */