/*
** Malloc function used within this file to allocate space from the buffer
** configured using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no
** such buffer exists or there is no space left in it, this function falls
** back to sqlite3Malloc().
**
** Multiple threads can run this routine at the same time. Global variables
** in pcache1 need to be protected via mutex.
*/
static void *pcache1Alloc(int nByte){
void *p = 0;
assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
if( nByte<=pcache1.szSlot ){
sqlite3_mutex_enter(pcache1.mutex);
p = (PgHdr1 *)pcache1.pFree;
if( p ){
pcache1.pFree = pcache1.pFree->pNext;
pcache1.nFreeSlot--;
pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
assert( pcache1.nFreeSlot>=0 );
sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_USED, 1);
}
sqlite3_mutex_leave(pcache1.mutex);
}
if( p==0 ){
/* Memory is not available in the SQLITE_CONFIG_PAGECACHE pool. Get
** it from sqlite3Malloc instead.
*/
p = sqlite3Malloc(nByte);
#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
if( p ){
int sz = sqlite3MallocSize(p);
sqlite3_mutex_enter(pcache1.mutex);
sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_OVERFLOW, sz);
sqlite3_mutex_leave(pcache1.mutex);
}
#endif
sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
}
return p;
}
/*
** Do a memory allocation with statistics and alarms. Assume the
** lock is already held.
*/
static int mallocWithAlarm(int n, void **pp){
int nFull;
void *p;
assert( sqlite3_mutex_held(mem0.mutex) );
nFull = sqlite3GlobalConfig.m.xRoundup(n);
sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, n);
if( mem0.alarmThreshold>0 ){
sqlite3_int64 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
if( nUsed >= mem0.alarmThreshold - nFull ){
mem0.nearlyFull = 1;
sqlite3MallocAlarm(nFull);
}else{
mem0.nearlyFull = 0;
}
}
p = sqlite3GlobalConfig.m.xMalloc(nFull);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
if( p==0 && mem0.alarmThreshold>0 ){
sqlite3MallocAlarm(nFull);
p = sqlite3GlobalConfig.m.xMalloc(nFull);
}
#endif
if( p ){
nFull = sqlite3MallocSize(p);
sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);
}
*pp = p;
return nFull;
}
/*
** Do a memory allocation with statistics and alarms. Assume the
** lock is already held.
*/
static void mallocWithAlarm(int n, void **pp){
void *p;
int nFull;
assert( sqlite3_mutex_held(mem0.mutex) );
assert( n>0 );
/* In Firefox (circa 2017-02-08), xRoundup() is remapped to an internal
** implementation of malloc_good_size(), which must be called in debug
** mode and specifically when the DMD "Dark Matter Detector" is enabled
** or else a crash results. Hence, do not attempt to optimize out the
** following xRoundup() call. */
nFull = sqlite3GlobalConfig.m.xRoundup(n);
#ifdef SQLITE_MAX_MEMORY
if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED)+nFull>SQLITE_MAX_MEMORY ){
*pp = 0;
return;
}
#endif
sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, n);
if( mem0.alarmThreshold>0 ){
sqlite3_int64 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
if( nUsed >= mem0.alarmThreshold - nFull ){
mem0.nearlyFull = 1;
sqlite3MallocAlarm(nFull);
}else{
mem0.nearlyFull = 0;
}
}
p = sqlite3GlobalConfig.m.xMalloc(nFull);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
if( p==0 && mem0.alarmThreshold>0 ){
sqlite3MallocAlarm(nFull);
p = sqlite3GlobalConfig.m.xMalloc(nFull);
}
#endif
if( p ){
nFull = sqlite3MallocSize(p);
sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);
}
*pp = p;
}
/*
** Allocate memory that is to be used and released right away.
** This routine is similar to alloca() in that it is not intended
** for situations where the memory might be held long-term. This
** routine is intended to get memory to old large transient data
** structures that would not normally fit on the stack of an
** embedded processor.
*/
void *sqlite3ScratchMalloc(int n){
void *p;
assert( n>0 );
sqlite3_mutex_enter(mem0.mutex);
sqlite3StatusHighwater(SQLITE_STATUS_SCRATCH_SIZE, n);
if( mem0.nScratchFree && sqlite3GlobalConfig.szScratch>=n ){
p = mem0.pScratchFree;
mem0.pScratchFree = mem0.pScratchFree->pNext;
mem0.nScratchFree--;
sqlite3StatusUp(SQLITE_STATUS_SCRATCH_USED, 1);
sqlite3_mutex_leave(mem0.mutex);
}else{
sqlite3_mutex_leave(mem0.mutex);
p = sqlite3Malloc(n);
if( sqlite3GlobalConfig.bMemstat && p ){
sqlite3_mutex_enter(mem0.mutex);
sqlite3StatusUp(SQLITE_STATUS_SCRATCH_OVERFLOW, sqlite3MallocSize(p));
sqlite3_mutex_leave(mem0.mutex);
}
sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);
}
assert( sqlite3_mutex_notheld(mem0.mutex) );
#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)
/* EVIDENCE-OF: R-12970-05880 SQLite will not use more than one scratch
** buffers per thread.
**
** This can only be checked in single-threaded mode.
*/
assert( scratchAllocOut==0 );
if( p ) scratchAllocOut++;
#endif
return p;
}
/*
** Change the size of an existing memory allocation
*/
void *sqlite3Realloc(void *pOld, u64 nBytes){
int nOld, nNew, nDiff;
void *pNew;
assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
assert( sqlite3MemdebugNoType(pOld, (u8)~MEMTYPE_HEAP) );
if( pOld==0 ){
return sqlite3Malloc(nBytes); /* IMP: R-04300-56712 */
}
if( nBytes==0 ){
sqlite3_free(pOld); /* IMP: R-26507-47431 */
return 0;
}
if( nBytes>=0x7fffff00 ){
/* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
return 0;
}
nOld = sqlite3MallocSize(pOld);
/* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
** argument to xRealloc is always a value returned by a prior call to
** xRoundup. */
nNew = sqlite3GlobalConfig.m.xRoundup((int)nBytes);
if( nOld==nNew ){
pNew = pOld;
}else if( sqlite3GlobalConfig.bMemstat ){
sqlite3_mutex_enter(mem0.mutex);
sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
nDiff = nNew - nOld;
if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >=
mem0.alarmThreshold-nDiff ){
sqlite3MallocAlarm(nDiff);
}
pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
if( pNew==0 && mem0.alarmThreshold>0 ){
sqlite3MallocAlarm((int)nBytes);
pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
}
if( pNew ){
nNew = sqlite3MallocSize(pNew);
sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
}
sqlite3_mutex_leave(mem0.mutex);
}else{
pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
}
assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-11148-40995 */
return pNew;
}
