Don't crash when using raster calculator with huge raster (refs #13336)

nyalldawson · nyalldawson · commit a665b7d72e70 · 2016-01-27T10:48:12.000+11:00
Now we abort and advise the user if insufficient memory is available
to perform the calculation.

At some future stage it would be nice to perform the calculations
in blocks to allow this scenario, but for now it's better not to
crash.
diff --git a/python/analysis/raster/qgsrastercalculator.sip b/python/analysis/raster/qgsrastercalculator.sip
@@ -18,6 +18,17 @@ class QgsRasterCalculator
 
   public:
 
+    //! Result of the calculation
+    enum Result
+    {
+      Success, /*!< Calculation sucessful */
+      CreateOutputError, /*!< Error creating output data file */
+      InputLayerError, /*!< Error reading input layer */
+      Cancelled, /*!< User cancelled calculation */
+      ParserError, /*!< Error parsing formula */
+      MemoryError, /*!< Error allocating memory for result */
+    };
+
     /** QgsRasterCalculator constructor.
      * @param formulaString formula for raster calculation
      * @param outputFile output file path
diff --git a/src/analysis/raster/qgsrastercalculator.cpp b/src/analysis/raster/qgsrastercalculator.cpp
@@ -69,7 +69,7 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )
   if ( !calcNode )
   {
     //error
-    return 4;
+    return static_cast<int>( ParserError );
   }
 
   QMap< QString, QgsRasterBlock* > inputBlocks;
@@ -78,7 +78,9 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )
   {
     if ( !it->raster ) // no raster layer in entry
     {
-      return 2;
+      delete calcNode;
+      qDeleteAll( inputBlocks );
+      return static_cast< int >( InputLayerError );
     }
 
     QgsRasterBlock* block = nullptr;
@@ -96,14 +98,20 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )
     {
       block = it->raster->dataProvider()->block( it->bandNumber, mOutputRectangle, mNumOutputColumns, mNumOutputRows );
     }
+    if ( block->isEmpty() )
+    {
+      delete calcNode;
+      qDeleteAll( inputBlocks );
+      return static_cast<int>( MemoryError );
+    }
     inputBlocks.insert( it->ref, block );
   }
 
   //open output dataset for writing
   GDALDriverH outputDriver = openOutputDriver();
   if ( !outputDriver )
   {
-    return 1;
+    return static_cast< int >( CreateOutputError );
   }
 
   GDALDatasetH outputDataset = openOutputFile( outputDriver );
@@ -169,11 +177,11 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )
   {
     //delete the dataset without closing (because it is faster)
     GDALDeleteDataset( outputDriver, TO8F( mOutputFile ) );
-    return 3;
+    return static_cast< int >( Cancelled );
   }
   GDALClose( outputDataset );
 
-  return 0;
+  return static_cast< int >( Success );
 }
 
 QgsRasterCalculator::QgsRasterCalculator()
diff --git a/src/analysis/raster/qgsrastercalculator.h b/src/analysis/raster/qgsrastercalculator.h
@@ -41,6 +41,17 @@ class ANALYSIS_EXPORT QgsRasterCalculator
 {
   public:
 
+    //! Result of the calculation
+    enum Result
+    {
+      Success = 0, /*!< Calculation sucessful */
+      CreateOutputError = 1, /*!< Error creating output data file */
+      InputLayerError = 2, /*!< Error reading input layer */
+      Cancelled = 3, /*!< User cancelled calculation */
+      ParserError = 4, /*!< Error parsing formula */
+      MemoryError = 5, /*!< Error allocating memory for result */
+    };
+
     /** QgsRasterCalculator constructor.
      * @param formulaString formula for raster calculation
      * @param outputFile output file path
@@ -70,6 +81,7 @@ class ANALYSIS_EXPORT QgsRasterCalculator
     /** Starts the calculation and writes new raster
       @param p progress bar (or 0 if called from non-gui code)
       @return 0 in case of success*/
+    //TODO QGIS 3.0 - return QgsRasterCalculator::Result
     int processCalculation( QProgressDialog* p = nullptr );
 
   private:
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -4305,12 +4305,46 @@ void QgisApp::showRasterCalculator()
 
     QProgressDialog p( tr( "Calculating..." ), tr( "Abort..." ), 0, 0 );
     p.setWindowModality( Qt::WindowModal );
-    if ( rc.processCalculation( &p ) == 0 )
+    QgsRasterCalculator::Result res = static_cast< QgsRasterCalculator::Result >( rc.processCalculation( &p ) );
+    switch ( res )
     {
-      if ( d.addLayerToProject() )
-      {
-        addRasterLayer( d.outputFile(), QFileInfo( d.outputFile() ).baseName() );
-      }
+      case QgsRasterCalculator::Success:
+        if ( d.addLayerToProject() )
+        {
+          addRasterLayer( d.outputFile(), QFileInfo( d.outputFile() ).baseName() );
+        }
+        messageBar()->pushMessage( tr( "Raster calculator" ),
+                                   tr( "Calculation complete." ),
+                                   QgsMessageBar::INFO, messageTimeout() );
+        break;
+
+      case QgsRasterCalculator::CreateOutputError:
+        messageBar()->pushMessage( tr( "Raster calculator" ),
+                                   tr( "Could not create destination file." ),
+                                   QgsMessageBar::CRITICAL );
+        break;
+
+      case QgsRasterCalculator::InputLayerError:
+        messageBar()->pushMessage( tr( "Raster calculator" ),
+                                   tr( "Could not read input layer." ),
+                                   QgsMessageBar::CRITICAL );
+        break;
+
+      case QgsRasterCalculator::Cancelled:
+        break;
+
+      case QgsRasterCalculator::ParserError:
+        messageBar()->pushMessage( tr( "Raster calculator" ),
+                                   tr( "Could not parse raster formula." ),
+                                   QgsMessageBar::CRITICAL );
+        break;
+
+      case QgsRasterCalculator::MemoryError:
+        messageBar()->pushMessage( tr( "Raster calculator" ),
+                                   tr( "Insufficient memory available for operation." ),
+                                   QgsMessageBar::CRITICAL );
+        break;
+
     }
   }
 }

Original file line number	Diff line number	Diff line change
`@@ -69,7 +69,7 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )`
`69`	`69`	`if ( !calcNode )`
`70`	`70`	`{`
`71`	`71`	`//error`
`72`		`- return 4;`
	`72`	`+ return static_cast<int>( ParserError );`
`73`	`73`	`}`
`74`	`74`
`75`	`75`	`QMap< QString, QgsRasterBlock* > inputBlocks;`
`@@ -78,7 +78,9 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )`
`78`	`78`	`{`
`79`	`79`	`if ( !it->raster ) // no raster layer in entry`
`80`	`80`	`{`
`81`		`- return 2;`
	`81`	`+ delete calcNode;`
	`82`	`+ qDeleteAll( inputBlocks );`
	`83`	`+ return static_cast< int >( InputLayerError );`
`82`	`84`	`}`
`83`	`85`
`84`	`86`	`QgsRasterBlock* block = nullptr;`
`@@ -96,14 +98,20 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )`
`96`	`98`	`{`
`97`	`99`	`block = it->raster->dataProvider()->block( it->bandNumber, mOutputRectangle, mNumOutputColumns, mNumOutputRows );`
`98`	`100`	`}`
	`101`	`+ if ( block->isEmpty() )`
	`102`	`+ {`
	`103`	`+ delete calcNode;`
	`104`	`+ qDeleteAll( inputBlocks );`
	`105`	`+ return static_cast<int>( MemoryError );`
	`106`	`+ }`
`99`	`107`	`inputBlocks.insert( it->ref, block );`
`100`	`108`	`}`
`101`	`109`
`102`	`110`	`//open output dataset for writing`
`103`	`111`	`GDALDriverH outputDriver = openOutputDriver();`
`104`	`112`	`if ( !outputDriver )`
`105`	`113`	`{`
`106`		`- return 1;`
	`114`	`+ return static_cast< int >( CreateOutputError );`
`107`	`115`	`}`
`108`	`116`
`109`	`117`	`GDALDatasetH outputDataset = openOutputFile( outputDriver );`
`@@ -169,11 +177,11 @@ int QgsRasterCalculator::processCalculation( QProgressDialog* p )`
`169`	`177`	`{`
`170`	`178`	`//delete the dataset without closing (because it is faster)`
`171`	`179`	`GDALDeleteDataset( outputDriver, TO8F( mOutputFile ) );`
`172`		`- return 3;`
	`180`	`+ return static_cast< int >( Cancelled );`
`173`	`181`	`}`
`174`	`182`	`GDALClose( outputDataset );`
`175`	`183`
`176`		`- return 0;`
	`184`	`+ return static_cast< int >( Success );`
`177`	`185`	`}`
`178`	`186`
`179`	`187`	`QgsRasterCalculator::QgsRasterCalculator()`