Disable VSI cache before GDALRasterIO, workaround for GDAL ticket 5170, fixes #8356

Author: blazek

src/providers/gdal/qgsgdalprovider.cpp

@@ -405,7 +405,7 @@ void QgsGdalProvider::readBlock( int theBandNo, int xBlock, int yBlock, void *bl
   // We have to read with correct data type consistent with other readBlock functions
   int xOff = xBlock * mXBlockSize;
   int yOff = yBlock * mYBlockSize;
-  GDALRasterIO( myGdalBand, GF_Read, xOff, yOff, mXBlockSize, mYBlockSize, block, mXBlockSize, mYBlockSize, ( GDALDataType ) mGdalDataType[theBandNo-1], 0, 0 );
+  gdalRasterIO( myGdalBand, GF_Read, xOff, yOff, mXBlockSize, mYBlockSize, block, mXBlockSize, mYBlockSize, ( GDALDataType ) mGdalDataType[theBandNo-1], 0, 0 );
 }
 
 void QgsGdalProvider::readBlock( int theBandNo, QgsRectangle  const & theExtent, int thePixelWidth, int thePixelHeight, void *theBlock )
@@ -580,7 +580,7 @@ void QgsGdalProvider::readBlock( int theBandNo, QgsRectangle  const & theExtent,
   GDALRasterBandH gdalBand = GDALGetRasterBand( mGdalDataset, theBandNo );
   GDALDataType type = ( GDALDataType )mGdalDataType[theBandNo-1];
   CPLErrorReset();
-  CPLErr err = GDALRasterIO( gdalBand, GF_Read,
+  CPLErr err = gdalRasterIO( gdalBand, GF_Read,
                              srcLeft, srcTop, srcWidth, srcHeight,
                              ( void * )tmpBlock,
                              tmpWidth, tmpHeight, type,
@@ -2533,7 +2533,7 @@ bool QgsGdalProvider::write( void* data, int band, int width, int height, int xO
   {
     return false;
   }
-  return GDALRasterIO( rasterBand, GF_Write, xOffset, yOffset, width, height, data, width, height, GDALGetRasterDataType( rasterBand ), 0, 0 ) == CE_None;
+  return gdalRasterIO( rasterBand, GF_Write, xOffset, yOffset, width, height, data, width, height, GDALGetRasterDataType( rasterBand ), 0, 0 ) == CE_None;
 }
 
 bool QgsGdalProvider::setNoDataValue( int bandNo, double noDataValue )

src/providers/gdal/qgsgdalproviderbase.cpp

@@ -294,3 +294,21 @@ GDALDatasetH QgsGdalProviderBase::gdalOpen( const char *pszFilename, GDALAccess
 
   return hDS;
 }
+
+CPLErr QgsGdalProviderBase::gdalRasterIO( GDALRasterBandH hBand, GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void * pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nPixelSpace, int nLineSpace )
+{
+  // See http://hub.qgis.org/issues/8356 and http://trac.osgeo.org/gdal/ticket/5170
+#if GDAL_VERSION_MAJOR == 1 && ( (GDAL_VERSION_MINOR == 9 && GDAL_VERSION_REV <= 2) || (GDAL_VERSION_MINOR == 10 && GDAL_VERSION_REV <= 0) )
+  char* pszOldVal = CPLStrdup( CPLGetConfigOption( "VSI_CACHE", "FALSE" ) );
+  CPLSetThreadLocalConfigOption( "VSI_CACHE", "FALSE" );
+#endif
+
+  CPLErr err = GDALRasterIO( hBand, eRWFlag, nXOff, nYOff, nXSize, nYSize, pData, nBufXSize, nBufYSize, eBufType, nPixelSpace, nLineSpace );
+
+#if GDAL_VERSION_MAJOR == 1 && ( (GDAL_VERSION_MINOR == 9 && GDAL_VERSION_REV <= 2) || (GDAL_VERSION_MINOR == 10 && GDAL_VERSION_REV <= 0) )
+  CPLSetThreadLocalConfigOption( "VSI_CACHE", pszOldVal );
+  CPLFree( pszOldVal );
+#endif
+
+  return err;
+}

src/providers/gdal/qgsgdalproviderbase.h

@@ -49,6 +49,10 @@ class QgsGdalProviderBase
 
     /** Wrapper function for GDALOpen to get around possible bugs in GDAL */
     static GDALDatasetH  gdalOpen( const char *pszFilename, GDALAccess eAccess );
+
+    /** Wrapper function for GDALRasterIO to get around possible bugs in GDAL */
+    static CPLErr gdalRasterIO( GDALRasterBandH hBand, GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void * pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nPixelSpace, int nLineSpace );
+
   protected:
 
     QGis::DataType dataTypeFromGdal( int theGdalDataType ) const;