SQLite

** Macros for querying and setting debugging fields of the EMemHdr object.
*/
#ifdef SQLITE_MEMDEBUG
# define isValidEMem(E)     ((E)->iEMemMagic==0xc0a43fad)
# define setValidEMem(E)    (E)->iEMemMagic = 0xc0a43fad
# define clearValidEMem(E)  (E)->iEMemMagic = 0x12345678
# define isChildEMem(E)     ((E)->isAChild!=0)
# define notChildEMem(E)    ((E)->isAChild==0)
# define setChildEMem(E)    (E)->isAChild = 1
# define clearChildEMem(E)  (E)->isAChild = 0
#else
# define isValidEMem(E)     1
# define setValidEMem(E)
# define clearValidEMem(E)
# define isChildEMem(E)     1
# define notChildEMem(E)    1
# define setChildEMem(E)
# define clearChildEMem(E)
#endif

/*
** This routine runs when the memory allocator sees that the
** total memory allocation is about to exceed the soft heap

}
void sqlite3ScratchFree(void *p){
  if( p ){
    if( sqlite3GlobalConfig.pScratch==0
           || p<sqlite3GlobalConfig.pScratch
           || p>=(void*)mem0.aScratchFree ){
      assert( sqlite3MemdebugHasType(p, MEMTYPE_SCRATCH) );
      assert( sqlite3MemdebugNoType(p, ~MEMTYPE_SCRATCH) );
      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
      if( sqlite3GlobalConfig.bMemstat ){
        int iSize = sqlite3MallocSize(p);
        sqlite3_mutex_enter(mem0.mutex);
        sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, -iSize);
        sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -iSize);
        sqlite3GlobalConfig.m.xFree(p);

** sqlite3Malloc() or sqlite3_malloc().
**
** The size returned is the usable size and does not include any
** bookkeeping overhead or sentinals at the end of the allocation.
*/
int sqlite3MallocSize(void *p){
  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
  assert( sqlite3MemdebugNoType(p, MEMTYPE_RECURSIVE) );
  return sqlite3GlobalConfig.m.xSize(p);
}
int sqlite3DbMallocSize(sqlite3 *db, void *pObj){
  EMemHdr *p = (EMemHdr*)pObj;
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  if( p ){
    p--;

}

/*
** Free memory previously obtained from sqlite3Malloc().
*/
void sqlite3_free(void *p){
  if( p==0 ) return;
  assert( sqlite3MemdebugNoType(p, MEMTYPE_RECURSIVE) );
  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
  if( sqlite3GlobalConfig.bMemstat ){
    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -sqlite3MallocSize(p));
    sqlite3GlobalConfig.m.xFree(p);
    sqlite3_mutex_leave(mem0.mutex);
  }else{

** allowed to delete a child allocation since that would leave a
** dangling child pointer in the parent.
*/
void sqlite3DbFree(sqlite3 *db, void *pObj){
  EMemHdr *p = (EMemHdr*)pObj;
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  if( p ) p--;
  assert( p==0 || notChildEMem(p) );  /* pObj is not child allocation */
  while( p ){
    EMemHdr *pNext = p->pESibling;
    assert( isValidEMem(p) );   /* pObj and all siblings are valid */
    if( p->pEChild ){
      clearChildEMem(p->pEChild);
      sqlite3DbFree(db, (void*)&p->pEChild[1]);
    }

    sqlite3_mutex_enter(mem0.mutex);
    sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, nBytes);
    if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED)+nNew-nOld >= 
          mem0.alarmThreshold ){
      sqlite3MallocAlarm(nNew-nOld);
    }
    assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
    assert( sqlite3MemdebugNoType(pOld, ~MEMTYPE_HEAP) );
    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    if( pNew==0 && mem0.alarmCallback ){
      sqlite3MallocAlarm(nBytes);
      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
    }
    if( pNew ){
      nNew = sqlite3MallocSize(pNew);

  assert( sqlite3_mutex_held(db->mutex) );
  if( db->mallocFailed==0 ){
    if( p==0 ){
      return sqlite3DbMallocRaw(db, n);
    }
    p--;
    assert( isValidEMem(p) );    /* pOld obtained from extended allocator */
    assert( notChildEMem(p) );   /* pOld must not be a child allocation */
    if( isLookaside(db, p) ){
      if( n+sizeof(EMemHdr)<=db->lookaside.sz ){
        return pOld;
      }
      pNew = sqlite3DbMallocRaw(db, n);
      if( pNew ){
        memcpy(pNew-1, p, db->lookaside.sz);

  EMemHdr *pParent = (EMemHdr*)pParentObj;
  EMemHdr *pChild = (EMemHdr*)pChildObj;
  if( pParent && pChild ){
    pParent--;
    assert( isValidEMem(pParent) );  /* pParentObj is an extended allocation */ 
    pChild--;
    assert( isValidEMem(pChild) );   /* pChildObj is an extended allocation */
    assert( notChildEMem(pChild) );  /* pChildObj not a child of another obj */
    pChild->pESibling = pParent->pEChild;
    pParent->pEChild = pChild;
    setChildEMem(pChild);
  }
}

/*

    if( (pHdr->eType&eType)==0 ){
      rc = 0;
    }
  }
  return rc;
}
 
/*
** Return TRUE if the mask of type in eType matches no bits of the type of the
** allocation p.  Also return true if p==NULL.
**
** This routine is designed for use within an assert() statement, to
** verify the type of an allocation.  For example:
**
**     assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );
*/
int sqlite3MemdebugNoType(void *p, u8 eType){
  int rc = 1;
  if( p ){
    struct MemBlockHdr *pHdr;
    pHdr = sqlite3MemsysGetHeader(p);
    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
    if( (pHdr->eType&eType)!=0 ){
      rc = 0;
    }
  }
  return rc;
}

/*
** Set the number of backtrace levels kept for each allocation.
** A value of zero turns off backtracing.  The number is always rounded
** up to a multiple of 2.
*/
void sqlite3MemdebugBacktrace(int depth){

** sqlite3MemdebugSetType() sets the "type" of an allocation to one of
** the MEMTYPE_* macros defined below.  The type must be a bitmask with
** a single bit set.
**
** sqlite3MemdebugHasType() returns true if any of the bits in its second
** argument match the type set by the previous sqlite3MemdebugSetType().
** sqlite3MemdebugHasType() is intended for use inside assert() statements.
**
** sqlite3MemdebugNoType() returns true if none of the bits in its second
** argument match the type set by the previous sqlite3MemdebugSetType().
**
** For example:
**
**     assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
**
** Perhaps the most important point is the difference between MEMTYPE_HEAP
** and MEMTYPE_DB.  If an allocation is MEMTYPE_DB, that means it might have
** been allocated by lookaside, except the allocation was too large or
** lookaside was already full.  It is important to verify that allocations
** that might have been satisfied by lookaside are not passed back to 
** non-lookaside free() routines.  Asserts such as the example above are
** placed on the non-lookaside free() routines to verify this constraint. 
**
** All of this is no-op for a production build.  It only comes into
** play when the SQLITE_MEMDEBUG compile-time option is used.
*/
#ifdef SQLITE_MEMDEBUG
  void sqlite3MemdebugSetType(void*,u8);
  int sqlite3MemdebugHasType(void*,u8);
  int sqlite3MemdebugNoType(void*,u8);
#else
# define sqlite3MemdebugSetType(X,Y)  /* no-op */
# define sqlite3MemdebugHasType(X,Y)  1
# define sqlite3MemdebugNoType(X,Y)   1
#endif
#define MEMTYPE_HEAP      0x01    /* General heap allocations */
#define MEMTYPE_DB        0x02    /* Associated with a database connection */
#define MEMTYPE_SCRATCH   0x04    /* Scratch allocations */
#define MEMTYPE_PCACHE    0x08    /* Page cache allocations */
#define MEMTYPE_RECURSIVE 0x10    /* Experimental */

#endif /* _SQLITEINT_H_ */