prevent concurrent access while creating iterators and updating cache info (#3224)

3nids · m-kuhn · commit 7eacd444d052 · 2016-06-21T18:02:06.000+02:00
#mutexmania kudos to @m-kuhn
diff --git a/src/core/qgsvectorlayer.h b/src/core/qgsvectorlayer.h
@@ -2211,6 +2211,8 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
 
     QgsAttributeTableConfig mAttributeTableConfig;
 
+    QMutex mFeatureSourceConstructorMutex;
+
     friend class QgsVectorLayerFeatureSource;
 };
 
diff --git a/src/core/qgsvectorlayerfeatureiterator.cpp b/src/core/qgsvectorlayerfeatureiterator.cpp
@@ -29,6 +29,7 @@
 QgsVectorLayerFeatureSource::QgsVectorLayerFeatureSource( QgsVectorLayer *layer )
     : mCrsId( 0 )
 {
+  QMutexLocker locker( &layer->mFeatureSourceConstructorMutex );
   mProviderFeatureSource = layer->dataProvider()->featureSource();
   mFields = layer->fields();
 
diff --git a/src/core/qgsvectorlayerjoinbuffer.cpp b/src/core/qgsvectorlayerjoinbuffer.cpp
@@ -62,6 +62,7 @@ static bool _hasCycleDFS( QgsVectorLayer* n, QHash<QgsVectorLayer*, int>& mark )
 
 bool QgsVectorLayerJoinBuffer::addJoin( const QgsVectorJoinInfo& joinInfo )
 {
+  QMutexLocker locker( &mMutex );
   mVectorJoins.push_back( joinInfo );
 
   // run depth-first search to detect cycles in the graph of joins between layers.
@@ -97,6 +98,7 @@ bool QgsVectorLayerJoinBuffer::addJoin( const QgsVectorJoinInfo& joinInfo )
 
 bool QgsVectorLayerJoinBuffer::removeJoin( const QString& joinLayerId )
 {
+  QMutexLocker locker( &mMutex );
   bool res = false;
   for ( int i = 0; i < mVectorJoins.size(); ++i )
   {
@@ -259,6 +261,7 @@ void QgsVectorLayerJoinBuffer::updateFields( QgsFields& fields )
 
 void QgsVectorLayerJoinBuffer::createJoinCaches()
 {
+  QMutexLocker locker( &mMutex );
   QList< QgsVectorJoinInfo >::iterator joinIt = mVectorJoins.begin();
   for ( ; joinIt != mVectorJoins.end(); ++joinIt )
   {
diff --git a/src/core/qgsvectorlayerjoinbuffer.h b/src/core/qgsvectorlayerjoinbuffer.h
@@ -101,6 +101,9 @@ class CORE_EXPORT QgsVectorLayerJoinBuffer : public QObject
 
     /** Caches attributes of join layer in memory if QgsVectorJoinInfo.memoryCache is true (and the cache is not already there)*/
     void cacheJoinLayer( QgsVectorJoinInfo& joinInfo );
+
+    /** Main mutex to protect most data members that can be modified concurrently */
+    QMutex mMutex;
 };
 
 #endif // QGSVECTORLAYERJOINBUFFER_H

Original file line number	Diff line number	Diff line change
`@@ -29,6 +29,7 @@`
`29`	`29`	`QgsVectorLayerFeatureSource::QgsVectorLayerFeatureSource( QgsVectorLayer *layer )`
`30`	`30`	`: mCrsId( 0 )`
`31`	`31`	`{`
	`32`	`+ QMutexLocker locker( &layer->mFeatureSourceConstructorMutex );`
`32`	`33`	`mProviderFeatureSource = layer->dataProvider()->featureSource();`
`33`	`34`	`mFields = layer->fields();`
`34`	`35`
Original file line number	Diff line number	Diff line change
`@@ -62,6 +62,7 @@ static bool _hasCycleDFS( QgsVectorLayer* n, QHash<QgsVectorLayer*, int>& mark )`
`62`	`62`
`63`	`63`	`bool QgsVectorLayerJoinBuffer::addJoin( const QgsVectorJoinInfo& joinInfo )`
`64`	`64`	`{`
	`65`	`+ QMutexLocker locker( &mMutex );`
`65`	`66`	`mVectorJoins.push_back( joinInfo );`
`66`	`67`
`67`	`68`	`// run depth-first search to detect cycles in the graph of joins between layers.`
`@@ -97,6 +98,7 @@ bool QgsVectorLayerJoinBuffer::addJoin( const QgsVectorJoinInfo& joinInfo )`
`97`	`98`
`98`	`99`	`bool QgsVectorLayerJoinBuffer::removeJoin( const QString& joinLayerId )`
`99`	`100`	`{`
	`101`	`+ QMutexLocker locker( &mMutex );`
`100`	`102`	`bool res = false;`
`101`	`103`	`for ( int i = 0; i < mVectorJoins.size(); ++i )`
`102`	`104`	`{`
`@@ -259,6 +261,7 @@ void QgsVectorLayerJoinBuffer::updateFields( QgsFields& fields )`
`259`	`261`
`260`	`262`	`void QgsVectorLayerJoinBuffer::createJoinCaches()`
`261`	`263`	`{`
	`264`	`+ QMutexLocker locker( &mMutex );`
`262`	`265`	`QList< QgsVectorJoinInfo >::iterator joinIt = mVectorJoins.begin();`
`263`	`266`	`for ( ; joinIt != mVectorJoins.end(); ++joinIt )`
`264`	`267`	`{`