Clear cached map renders if dependent layer is removed

nyalldawson · nyalldawson · commit c1b5da4726f2 · 2017-02-06T11:35:46.000+10:00
diff --git a/src/core/qgsmaprenderercache.cpp b/src/core/qgsmaprenderercache.cpp
@@ -40,6 +40,7 @@ void QgsMapRendererCache::clearInternal()
     if ( layer.data() )
     {
       disconnect( layer.data(), &QgsMapLayer::repaintRequested, this, &QgsMapRendererCache::layerRequestedRepaint );
+      disconnect( layer.data(), &QgsMapLayer::willBeDeleted, this, &QgsMapRendererCache::layerRequestedRepaint );
     }
   }
   mCachedImages.clear();
@@ -55,6 +56,7 @@ void QgsMapRendererCache::dropUnusedConnections()
     if ( layer.data() )
     {
       disconnect( layer.data(), &QgsMapLayer::repaintRequested, this, &QgsMapRendererCache::layerRequestedRepaint );
+      disconnect( layer.data(), &QgsMapLayer::willBeDeleted, this, &QgsMapRendererCache::layerRequestedRepaint );
     }
   }
 
@@ -110,6 +112,7 @@ void QgsMapRendererCache::setCacheImage( const QString& cacheKey, const QImage&
       if ( !mConnectedLayers.contains( QgsWeakMapLayerPointer( layer ) ) )
       {
         connect( layer, &QgsMapLayer::repaintRequested, this, &QgsMapRendererCache::layerRequestedRepaint );
+        connect( layer, &QgsMapLayer::willBeDeleted, this, &QgsMapRendererCache::layerRequestedRepaint );
         mConnectedLayers << layer;
       }
     }
diff --git a/tests/src/python/test_qgsmaprenderercache.py b/tests/src/python/test_qgsmaprenderercache.py
@@ -208,9 +208,35 @@ def testDependentLayers(self):
         cache.setCacheImage('depends', im, [layer1, layer2])
         self.assertEqual(set(cache.dependentLayers('depends')), set([layer1, layer2]))
 
-        # try deleting a layer in the meantime..
+    def testLayerRemoval(self):
+        """test that cached image is cleared when a dependent layer is removed"""
+        cache = QgsMapRendererCache()
+        layer1 = QgsVectorLayer("Point?field=fldtxt:string",
+                                "layer1", "memory")
+        layer2 = QgsVectorLayer("Point?field=fldtxt:string",
+                                "layer2", "memory")
+        im = QImage(200, 200, QImage.Format_RGB32)
+        cache.setCacheImage('depends', im, [layer1, layer2])
+        cache.setCacheImage('depends2', im, [layer1])
+        cache.setCacheImage('depends3', im, [layer2])
+        cache.setCacheImage('no depends', im, [])
+        self.assertTrue(cache.hasCacheImage('depends'))
+        self.assertTrue(cache.hasCacheImage('depends2'))
+        self.assertTrue(cache.hasCacheImage('depends3'))
+        self.assertTrue(cache.hasCacheImage('no depends'))
+
+        # try deleting a layer
         layer2 = None
-        self.assertEqual(set(cache.dependentLayers('depends')), set([layer1]))
+        self.assertFalse(cache.hasCacheImage('depends'))
+        self.assertTrue(cache.hasCacheImage('depends2'))
+        self.assertFalse(cache.hasCacheImage('depends3'))
+        self.assertTrue(cache.hasCacheImage('no depends'))
+
+        layer1 = None
+        self.assertFalse(cache.hasCacheImage('depends'))
+        self.assertFalse(cache.hasCacheImage('depends2'))
+        self.assertFalse(cache.hasCacheImage('depends3'))
+        self.assertTrue(cache.hasCacheImage('no depends'))
 
 
 if __name__ == '__main__':

Original file line number	Diff line number	Diff line change
`@@ -40,6 +40,7 @@ void QgsMapRendererCache::clearInternal()`
`40`	`40`	`if ( layer.data() )`
`41`	`41`	`{`
`42`	`42`	`disconnect( layer.data(), &QgsMapLayer::repaintRequested, this, &QgsMapRendererCache::layerRequestedRepaint );`
	`43`	`+ disconnect( layer.data(), &QgsMapLayer::willBeDeleted, this, &QgsMapRendererCache::layerRequestedRepaint );`
`43`	`44`	`}`
`44`	`45`	`}`
`45`	`46`	`mCachedImages.clear();`
`@@ -55,6 +56,7 @@ void QgsMapRendererCache::dropUnusedConnections()`
`55`	`56`	`if ( layer.data() )`
`56`	`57`	`{`
`57`	`58`	`disconnect( layer.data(), &QgsMapLayer::repaintRequested, this, &QgsMapRendererCache::layerRequestedRepaint );`
	`59`	`+ disconnect( layer.data(), &QgsMapLayer::willBeDeleted, this, &QgsMapRendererCache::layerRequestedRepaint );`
`58`	`60`	`}`
`59`	`61`	`}`
`60`	`62`
`@@ -110,6 +112,7 @@ void QgsMapRendererCache::setCacheImage( const QString& cacheKey, const QImage&`
`110`	`112`	`if ( !mConnectedLayers.contains( QgsWeakMapLayerPointer( layer ) ) )`
`111`	`113`	`{`
`112`	`114`	`connect( layer, &QgsMapLayer::repaintRequested, this, &QgsMapRendererCache::layerRequestedRepaint );`
	`115`	`+ connect( layer, &QgsMapLayer::willBeDeleted, this, &QgsMapRendererCache::layerRequestedRepaint );`
`113`	`116`	`mConnectedLayers << layer;`
`114`	`117`	`}`
`115`	`118`	`}`