[processing] More responsive cancelation for dissolve algorithm

nyalldawson · nyalldawson · commit 916805cf0479 · 2019-02-12T12:58:55.000+10:00
diff --git a/src/analysis/processing/qgsalgorithmdissolve.cpp b/src/analysis/processing/qgsalgorithmdissolve.cpp
@@ -219,11 +219,16 @@ QVariantMap QgsDissolveAlgorithm::processAlgorithm( const QVariantMap &parameter
     // See: https://issues.qgis.org/issues/20591 - Dissolve tool failing to produce outputs
     if ( ! result.lastError().isEmpty() && parts.count() >  2 )
     {
+      if ( feedback->isCanceled() )
+        return result;
+
       feedback->pushDebugInfo( QObject::tr( "GEOS exception: taking the slower route ..." ) );
       result = QgsGeometry();
       for ( const auto &p : parts )
       {
         result = QgsGeometry::unaryUnion( QVector< QgsGeometry >() << result << p );
+        if ( feedback->isCanceled() )
+          return result;
       }
     }
     if ( ! result.lastError().isEmpty() )

Original file line number	Diff line number	Diff line change
`@@ -219,11 +219,16 @@ QVariantMap QgsDissolveAlgorithm::processAlgorithm( const QVariantMap &parameter`
`219`	`219`	`// See: https://issues.qgis.org/issues/20591 - Dissolve tool failing to produce outputs`
`220`	`220`	`if ( ! result.lastError().isEmpty() && parts.count() > 2 )`
`221`	`221`	`{`
	`222`	`+ if ( feedback->isCanceled() )`
	`223`	`+ return result;`
	`224`	`+`
`222`	`225`	`feedback->pushDebugInfo( QObject::tr( "GEOS exception: taking the slower route ..." ) );`
`223`	`226`	`result = QgsGeometry();`
`224`	`227`	`for ( const auto &p : parts )`
`225`	`228`	`{`
`226`	`229`	`result = QgsGeometry::unaryUnion( QVector< QgsGeometry >() << result << p );`
	`230`	`+ if ( feedback->isCanceled() )`
	`231`	`+ return result;`
`227`	`232`	`}`
`228`	`233`	`}`
`229`	`234`	`if ( ! result.lastError().isEmpty() )`