Merge pull request #3034 from rouault/ogr_concurrent_opening

[BUGFIX / FEATURE] [OGR] Allow concurrent edition of Shapefiles and Tabfiles in QGIS & MapInfo
qgis · May 10, 2016 · 0f6838d · 0f6838d
2 parents 7ae80b1 + 52de4fb
commit 0f6838d
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Showing 10 changed files with 631 additions and 30 deletions.
diff --git a/python/core/qgsdataprovider.sip b/python/core/qgsdataprovider.sip
@@ -223,6 +223,47 @@ class QgsDataProvider : QObject
      */
     virtual void invalidateConnections( const QString& connection );
 
+    /** Enter update mode.
+     *
+     * This is aimed at providers that can open differently the connection to
+     * the datasource, according it to be in update mode or in read-only mode.
+     * A call to this method shall be balanced with a call to leaveUpdateMode(),
+     * if this method returns true.
+     *
+     * Most providers will have an empty implementation for that method.
+     *
+     * For backward compatibility, providers that implement enterUpdateMode() should
+     * still make sure to allow editing operations to work even if enterUpdateMode()
+     * is not explicitly called.
+     *
+     * Several successive calls to enterUpdateMode() can be done. So there is
+     * a concept of stack of calls that must be handled by the provider. Only the first
+     * call to enterUpdateMode() will really turn update mode on.
+     *
+     * @return true in case of success (or no-op implementation), false in case of failure
+     *
+     * @note added in QGIS 2.16
+     */
+    virtual bool enterUpdateMode();
+
+    /** Leave update mode.
+     *
+     * This is aimed at providers that can open differently the connection to
+     * the datasource, according it to be in update mode or in read-only mode.
+     * This method shall be balanced with a succesful call to enterUpdateMode().
+     *
+     * Most providers will have an empty implementation for that method.
+     *
+     * Several successive calls to enterUpdateMode() can be done. So there is
+     * a concept of stack of calls that must be handled by the provider. Only the last
+     * call to leaveUpdateMode() will really turn update mode off.
+     *
+     * @return true in case of success (or no-op implementation), false in case of failure
+     *
+     * @note added in QGIS 2.16
+     */
+    virtual bool leaveUpdateMode();
+
   signals:
 
     /**

diff --git a/src/core/qgsdataprovider.h b/src/core/qgsdataprovider.h
@@ -311,6 +311,47 @@ class CORE_EXPORT QgsDataProvider : public QObject
      */
     virtual void invalidateConnections( const QString& connection ) { Q_UNUSED( connection ); }
 
+    /** Enter update mode.
+     *
+     * This is aimed at providers that can open differently the connection to
+     * the datasource, according it to be in update mode or in read-only mode.
+     * A call to this method shall be balanced with a call to leaveUpdateMode(),
+     * if this method returns true.
+     *
+     * Most providers will have an empty implementation for that method.
+     *
+     * For backward compatibility, providers that implement enterUpdateMode() should
+     * still make sure to allow editing operations to work even if enterUpdateMode()
+     * is not explicitly called.
+     *
+     * Several successive calls to enterUpdateMode() can be done. So there is
+     * a concept of stack of calls that must be handled by the provider. Only the first
+     * call to enterUpdateMode() will really turn update mode on.
+     *
+     * @return true in case of success (or no-op implementation), false in case of failure.
+     *
+     * @note added in QGIS 2.16
+     */
+    virtual bool enterUpdateMode() { return true; }
+
+    /** Leave update mode.
+     *
+     * This is aimed at providers that can open differently the connection to
+     * the datasource, according it to be in update mode or in read-only mode.
+     * This method shall be balanced with a succesful call to enterUpdateMode().
+     *
+     * Most providers will have an empty implementation for that method.
+     *
+     * Several successive calls to enterUpdateMode() can be done. So there is
+     * a concept of stack of calls that must be handled by the provider. Only the last
+     * call to leaveUpdateMode() will really turn update mode off.
+     *
+     * @return true in case of success (or no-op implementation), false in case of failure.
+     *
+     * @note added in QGIS 2.16
+     */
+    virtual bool leaveUpdateMode() { return true; }
+
   signals:
 
     /**

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -377,6 +377,7 @@ void QgsVectorLayer::reload()
   if ( mDataProvider )
   {
     mDataProvider->reloadData();
+    updateFields();
   }
 }
 
@@ -1454,6 +1455,8 @@ bool QgsVectorLayer::startEditing()
 
   emit beforeEditingStarted();
 
+  mDataProvider->enterUpdateMode();
+
   if ( mDataProvider->transaction() )
   {
     mEditBuffer = new QgsVectorLayerEditPassthrough( this );
@@ -2424,6 +2427,8 @@ bool QgsVectorLayer::commitChanges()
   updateFields();
   mDataProvider->updateExtents();
 
+  mDataProvider->leaveUpdateMode();
+
   emit repaintRequested();
 
   return success;
@@ -2474,6 +2479,8 @@ bool QgsVectorLayer::rollBack( bool deleteBuffer )
   if ( rollbackExtent )
     updateExtents();
 
+  mDataProvider->leaveUpdateMode();
+
   emit repaintRequested();
   return true;
 }

diff --git a/src/providers/ogr/qgsogrfeatureiterator.cpp b/src/providers/ogr/qgsogrfeatureiterator.cpp
@@ -46,6 +46,10 @@ QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrFeatureSource* source, bool
   mFeatureFetched = false;
 
   mConn = QgsOgrConnPool::instance()->acquireConnection( mSource->mProvider->dataSourceUri() );
+  if ( !mConn->ds )
+  {
+    return;
+  }
 
   if ( mSource->mLayerName.isNull() )
   {
@@ -55,10 +59,18 @@ QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrFeatureSource* source, bool
   {
     ogrLayer = OGR_DS_GetLayerByName( mConn->ds, TO8( mSource->mLayerName ) );
   }
+  if ( !ogrLayer )
+  {
+    return;
+  }
 
   if ( !mSource->mSubsetString.isEmpty() )
   {
     ogrLayer = QgsOgrProviderUtils::setSubsetString( ogrLayer, mConn->ds, mSource->mEncoding, mSource->mSubsetString );
+    if ( !ogrLayer )
+    {
+      return;
+    }
     mSubsetStringSet = true;
   }
 
@@ -212,7 +224,7 @@ bool QgsOgrFeatureIterator::fetchFeature( QgsFeature& feature )
 {
   feature.setValid( false );
 
-  if ( mClosed )
+  if ( mClosed || !ogrLayer )
     return false;
 
   if ( mRequest.filterType() == QgsFeatureRequest::FilterFid )
@@ -257,7 +269,7 @@ bool QgsOgrFeatureIterator::fetchFeature( QgsFeature& feature )
 
 bool QgsOgrFeatureIterator::rewind()
 {
-  if ( mClosed )
+  if ( mClosed || !ogrLayer )
     return false;
 
   OGR_L_ResetReading( ogrLayer );