Safer iterator closing, by always calling ::close() instead of

directly manipulating mClosed

Fixes a crash in the memory data provider (also likely fixes
issues in other providers)

src/core/providers/memory/qgsmemoryfeatureiterator.cpp

@@ -39,7 +39,7 @@ QgsMemoryFeatureIterator::QgsMemoryFeatureIterator( QgsMemoryFeatureSource *sour
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 

src/core/qgscachedfeatureiterator.cpp

@@ -32,7 +32,7 @@ QgsCachedFeatureIterator::QgsCachedFeatureIterator( QgsVectorLayerCache *vlCache
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
   if ( !mFilterRect.isNull() )
@@ -118,7 +118,7 @@ QgsCachedFeatureWriterIterator::QgsCachedFeatureWriterIterator( QgsVectorLayerCa
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
   if ( !mFilterRect.isNull() )

src/core/qgsvectorlayerfeatureiterator.cpp

@@ -124,7 +124,7 @@ QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayerFeat
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
   if ( !mFilterRect.isNull() )

src/providers/arcgisrest/qgsafsfeatureiterator.cpp

@@ -50,7 +50,7 @@ QgsAfsFeatureIterator::QgsAfsFeatureIterator( QgsAfsFeatureSource *source, bool
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 }

src/providers/db2/qgsdb2featureiterator.cpp

@@ -45,7 +45,7 @@ QgsDb2FeatureIterator::QgsDb2FeatureIterator( QgsDb2FeatureSource *source, bool
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 

src/providers/delimitedtext/qgsdelimitedtextfeatureiterator.cpp

@@ -50,7 +50,7 @@ QgsDelimitedTextFeatureIterator::QgsDelimitedTextFeatureIterator( QgsDelimitedTe
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 

src/providers/gpx/qgsgpxfeatureiterator.cpp

@@ -40,7 +40,7 @@ QgsGPXFeatureIterator::QgsGPXFeatureIterator( QgsGPXFeatureSource *source, bool
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 

src/providers/mssql/qgsmssqlfeatureiterator.cpp

@@ -45,7 +45,7 @@ QgsMssqlFeatureIterator::QgsMssqlFeatureIterator( QgsMssqlFeatureSource *source,
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 
@@ -413,13 +413,7 @@ bool QgsMssqlFeatureIterator::rewind()
   if ( !result )
   {
     QgsDebugMsg( mQuery->lastError().text() );
-    mQuery.reset();
-    if ( mDatabase.isOpen() )
-      mDatabase.close();
-
-    iteratorClosed();
-
-    mClosed = true;
+    close();
     return false;
   }
 

src/providers/ogr/qgsogrfeatureiterator.cpp

@@ -88,7 +88,7 @@ QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrFeatureSource *source, bool
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 

src/providers/virtual/qgsvirtuallayerfeatureiterator.cpp

@@ -54,7 +54,7 @@ QgsVirtualLayerFeatureIterator::QgsVirtualLayerFeatureIterator( QgsVirtualLayerF
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }
 

src/providers/wfs/qgswfsfeatureiterator.cpp

@@ -824,7 +824,7 @@ QgsWFSFeatureIterator::QgsWFSFeatureIterator( QgsWFSFeatureSource *source,
   catch ( QgsCsException & )
   {
     // can't reproject mFilterRect
-    mClosed = true;
+    close();
     return;
   }