Add fast truncate implementation for memory provider

qgis · Dec 27, 2018 · fd0fba7 · fd0fba7
1 parent b0aae0b
commit fd0fba7
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/src/core/providers/memory/qgsmemoryprovider.cpp b/src/core/providers/memory/qgsmemoryprovider.cpp
@@ -616,9 +616,16 @@ QgsVectorDataProvider::Capabilities QgsMemoryProvider::capabilities() const
 {
   return AddFeatures | DeleteFeatures | ChangeGeometries |
          ChangeAttributeValues | AddAttributes | DeleteAttributes | RenameAttributes | CreateSpatialIndex |
-         SelectAtId | CircularGeometries;
+         SelectAtId | CircularGeometries | FastTruncate;
 }
 
+bool QgsMemoryProvider::truncate()
+{
+  mFeatures.clear();
+  clearMinMaxCache();
+  mExtent.setMinimal();
+  return true;
+}
 
 void QgsMemoryProvider::updateExtents()
 {

diff --git a/src/core/providers/memory/qgsmemoryprovider.h b/src/core/providers/memory/qgsmemoryprovider.h
@@ -68,6 +68,7 @@ class QgsMemoryProvider : public QgsVectorDataProvider
     bool supportsSubsetString() const override { return true; }
     bool createSpatialIndex() override;
     QgsVectorDataProvider::Capabilities capabilities() const override;
+    bool truncate() override;
 
     /* Implementation of functions from QgsDataProvider */