int GDALRasterBlock::TakeLock()
{
const int nLockVal = AddLock();
CPLAssert(nLockVal >= 0);
if( bSleepsForBockCacheDebug )
CPLSleep(CPLAtof(
CPLGetConfigOption("GDAL_RB_TRYGET_SLEEP_AFTER_TAKE_LOCK", "0")));
if( nLockVal == 0 )
{
#ifdef DEBUG
CPLDebug(
"GDAL",
"TakeLock(%p): Block(%d,%d,%p) is being evicted while trying to "
"reacquire it.",
reinterpret_cast<void *>(CPLGetPID()), nXOff, nYOff, poBand );
#endif
// The block is being evicted by GDALRasterBlock::Internalize()
// or FlushCacheBlock(), so wait for this to be done before trying
// again.
DropLock();
// wait for the block having been unreferenced
TAKE_LOCK;
return FALSE;
}
Touch();
return TRUE;
}
CPLErr GDALRasterBlock::Internalize()
{
CPLMutexHolderD(&hRBMutex);
void *pNewData;
int nSizeInBytes;
GIntBig nCurCacheMax = GDALGetCacheMax64();
/* No risk of overflow as it is checked in GDALRasterBand::InitBlockInfo() */
nSizeInBytes = nXSize * nYSize * (GDALGetDataTypeSize(eType) / 8);
pNewData = VSIMalloc(nSizeInBytes);
if (pNewData == NULL)
{
CPLError(CE_Failure, CPLE_OutOfMemory,
"GDALRasterBlock::Internalize : Out of memory allocating %d bytes.",
nSizeInBytes);
return(CE_Failure);
}
if (pData != NULL)
memcpy(pNewData, pData, nSizeInBytes);
pData = pNewData;
/* -------------------------------------------------------------------- */
/* Flush old blocks if we are nearing our memory limit. */
/* -------------------------------------------------------------------- */
AddLock(); /* don't flush this block! */
nCacheUsed += nSizeInBytes;
while (nCacheUsed > nCurCacheMax)
{
GIntBig nOldCacheUsed = nCacheUsed;
GDALFlushCacheBlock();
if (nCacheUsed == nOldCacheUsed)
break;
}
/* -------------------------------------------------------------------- */
/* Add this block to the list. */
/* -------------------------------------------------------------------- */
Touch();
DropLock();
return(CE_None);
}
