Merge pull request #7245 from rouault/gpkg_transactions

[OGR provider] [FEATURE] Add support for transactions on GPKG databases

python/core/auto_generated/qgstransaction.sip.in

@@ -146,6 +146,7 @@ returns the last created savepoint
 .. versionadded:: 3.0
 %End
 
+
   signals:
 
     void afterRollback();

src/core/qgstransaction.cpp

@@ -51,7 +51,7 @@ QgsTransaction *QgsTransaction::create( const QSet<QgsVectorLayer *> &layers )
 
   QgsVectorLayer *firstLayer = *layers.constBegin();
 
-  QString connStr = QgsDataSourceUri( firstLayer->source() ).connectionInfo( false );
+  QString connStr = connectionString( firstLayer->source() );
   QString providerKey = firstLayer->dataProvider()->name();
   std::unique_ptr<QgsTransaction> transaction( QgsTransaction::create( connStr, providerKey ) );
   if ( transaction )
@@ -81,6 +81,46 @@ QgsTransaction::~QgsTransaction()
   setLayerTransactionIds( nullptr );
 }
 
+// For the needs of the OGR provider with GeoPackage datasources, remove
+// any reference to layers in the connection string
+QString QgsTransaction::removeLayerIdOrName( const QString &str )
+{
+  QString res( str );
+
+  for ( int i = 0; i < 2; i++ )
+  {
+    int pos = res.indexOf( i == 0 ? QLatin1String( "|layername=" ) :  QLatin1String( "|layerid=" ) );
+    if ( pos >= 0 )
+    {
+      int end = res.indexOf( '|', pos + 1 );
+      if ( end >= 0 )
+      {
+        res = res.mid( 0, pos ) + res.mid( end );
+      }
+      else
+      {
+        res = res.mid( 0, pos );
+      }
+    }
+  }
+  return res;
+}
+
+///@cond PRIVATE
+QString QgsTransaction::connectionString( const QString &layerName )
+{
+  QString connString = QgsDataSourceUri( layerName ).connectionInfo( false );
+  // In the case of a OGR datasource, connectionInfo() will return an empty
+  // string. In that case, use the layer->source() itself, and strip any
+  // reference to layers from it.
+  if ( connString.isEmpty() )
+  {
+    connString = removeLayerIdOrName( layerName );
+  }
+  return connString;
+}
+///@endcond
+
 bool QgsTransaction::addLayer( QgsVectorLayer *layer )
 {
   if ( !layer )
@@ -90,17 +130,18 @@ bool QgsTransaction::addLayer( QgsVectorLayer *layer )
     return false;
 
   //test if provider supports transactions
-  if ( !layer->dataProvider() || ( layer->dataProvider()->capabilities() & QgsVectorDataProvider::TransactionSupport ) == 0 )
+  if ( !supportsTransaction( layer ) )
     return false;
 
   if ( layer->dataProvider()->transaction() )
     return false;
 
   //connection string not compatible
-  if ( QgsDataSourceUri( layer->source() ).connectionInfo( false ) != mConnString )
+
+  if ( connectionString( layer->source() ) != mConnString )
   {
     QgsDebugMsg( QString( "Couldn't start transaction because connection string for layer %1 : '%2' does not match '%3'" ).arg(
-                   layer->id(), QgsDataSourceUri( layer->source() ).connectionInfo( false ), mConnString ) );
+                   layer->id(), connectionString( layer->source() ), mConnString ) );
     return false;
   }
 
@@ -162,11 +203,11 @@ bool QgsTransaction::rollback( QString &errorMsg )
 
 bool QgsTransaction::supportsTransaction( const QgsVectorLayer *layer )
 {
-  std::unique_ptr< QLibrary > lib( QgsProviderRegistry::instance()->createProviderLibrary( layer->providerType() ) );
-  if ( !lib )
+  //test if provider supports transactions
+  if ( !layer->dataProvider() || ( layer->dataProvider()->capabilities() & QgsVectorDataProvider::TransactionSupport ) == 0 )
     return false;
 
-  return lib->resolve( "createTransaction" );
+  return true;
 }
 
 void QgsTransaction::onLayerDeleted()

src/core/qgstransaction.h

@@ -158,6 +158,11 @@ class CORE_EXPORT QgsTransaction : public QObject SIP_ABSTRACT
      */
     bool lastSavePointIsDirty() const { return mLastSavePointIsDirty; }
 
+///@cond PRIVATE
+    // For internal use only, or by QgsTransactionGroup
+    static QString connectionString( const QString &layerName ) SIP_SKIP;
+///@endcond
+
   signals:
 
     /**
@@ -188,6 +193,8 @@ class CORE_EXPORT QgsTransaction : public QObject SIP_ABSTRACT
 
     void setLayerTransactionIds( QgsTransaction *transaction );
 
+    static QString removeLayerIdOrName( const QString &str );
+
     virtual bool beginTransaction( QString &error, int statementTimeout ) = 0;
     virtual bool commitTransaction( QString &error ) = 0;
     virtual bool rollbackTransaction( QString &error ) = 0;

src/core/qgstransactiongroup.cpp

@@ -33,8 +33,7 @@ bool QgsTransactionGroup::addLayer( QgsVectorLayer *layer )
   if ( !QgsTransaction::supportsTransaction( layer ) )
     return false;
 
-  QString connString = QgsDataSourceUri( layer->source() ).connectionInfo();
-
+  QString connString = QgsTransaction::connectionString( layer->source() );
   if ( mConnString.isEmpty() )
   {
     mConnString = connString;
@@ -74,6 +73,8 @@ void QgsTransactionGroup::onEditingStarted()
     return;
 
   mTransaction.reset( QgsTransaction::create( mConnString, mProviderKey ) );
+  if ( !mTransaction )
+    return;
 
   QString errorMsg;
   mTransaction->begin( errorMsg );

src/providers/ogr/CMakeLists.txt

@@ -9,6 +9,7 @@ SET (OGR_SRCS
     qgsgeopackagerasterwritertask.cpp
     qgsogrdbconnection.cpp
     qgsogrdbtablemodel.cpp
+    qgsogrtransaction.cpp
 )
 
 SET(OGR_MOC_HDRS
@@ -19,6 +20,7 @@ SET(OGR_MOC_HDRS
     qgsgeopackagerasterwritertask.h
     qgsogrdbconnection.h
     qgsogrdbtablemodel.h
+    qgsogrtransaction.h
 )
 
 IF (WITH_GUI)

src/providers/ogr/qgsogrfeatureiterator.cpp

@@ -26,6 +26,7 @@
 #include "qgssettings.h"
 #include "qgsexception.h"
 #include "qgswkbtypes.h"
+#include "qgsogrtransaction.h"
 
 #include <QTextCodec>
 #include <QFile>
@@ -42,38 +43,51 @@ QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrFeatureSource *source, bool
   : QgsAbstractFeatureIteratorFromSource<QgsOgrFeatureSource>( source, ownSource, request )
   , mFilterFids( mRequest.filterFids() )
   , mFilterFidsIt( mFilterFids.constBegin() )
+  , mSharedDS( source->mSharedDS )
 {
-  //QgsDebugMsg( "Feature iterator of " + mSource->mLayerName + ": acquiring connection");
-  mConn = QgsOgrConnPool::instance()->acquireConnection( QgsOgrProviderUtils::connectionPoolId( mSource->mDataSource ) );
-  if ( !mConn->ds )
+  if ( mSharedDS )
   {
-    return;
-  }
-
-  if ( mSource->mLayerName.isNull() )
-  {
-    mOgrLayer = GDALDatasetGetLayer( mConn->ds, mSource->mLayerIndex );
+    mOgrLayer = mSharedDS->createSQLResultLayer( mSource->mEncoding, mSource->mLayerName, mSource->mLayerIndex );
+    if ( !mOgrLayer )
+    {
+      return;
+    }
   }
   else
   {
-    mOgrLayer = GDALDatasetGetLayerByName( mConn->ds, mSource->mLayerName.toUtf8().constData() );
-  }
-  if ( !mOgrLayer )
-  {
-    return;
-  }
+    //QgsDebugMsg( "Feature iterator of " + mSource->mLayerName + ": acquiring connection");
+    mConn = QgsOgrConnPool::instance()->acquireConnection( QgsOgrProviderUtils::connectionPoolId( mSource->mDataSource ) );
+    if ( !mConn->ds )
+    {
+      return;
+    }
 
-  if ( !mSource->mSubsetString.isEmpty() )
-  {
-    mOgrOrigLayer = mOgrLayer;
-    mOgrLayerWithFid = QgsOgrProviderUtils::setSubsetString( mOgrLayer, mConn->ds, mSource->mEncoding, QString(), true, &mOrigFidAdded );
-    mOgrLayer = QgsOgrProviderUtils::setSubsetString( mOgrLayer, mConn->ds, mSource->mEncoding, mSource->mSubsetString, true, &mOrigFidAdded );
+    if ( mSource->mLayerName.isNull() )
+    {
+      mOgrLayer = GDALDatasetGetLayer( mConn->ds, mSource->mLayerIndex );
+    }
+    else
+    {
+      mOgrLayer = GDALDatasetGetLayerByName( mConn->ds, mSource->mLayerName.toUtf8().constData() );
+    }
     if ( !mOgrLayer )
     {
-      close();
       return;
     }
+
+    if ( !mSource->mSubsetString.isEmpty() )
+    {
+      mOgrOrigLayer = mOgrLayer;
+      mOgrLayerWithFid = QgsOgrProviderUtils::setSubsetString( mOgrLayer, mConn->ds, mSource->mEncoding, QString(), true, &mOrigFidAdded );
+      mOgrLayer = QgsOgrProviderUtils::setSubsetString( mOgrLayer, mConn->ds, mSource->mEncoding, mSource->mSubsetString, true, &mOrigFidAdded );
+      if ( !mOgrLayer )
+      {
+        close();
+        return;
+      }
+    }
   }
+  QMutexLocker locker( mSharedDS ? &mSharedDS->mutex() : nullptr );
 
   if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
   {
@@ -237,6 +251,8 @@ bool QgsOgrFeatureIterator::fetchFeatureWithId( QgsFeatureId id, QgsFeature &fea
 
 bool QgsOgrFeatureIterator::fetchFeature( QgsFeature &feature )
 {
+  QMutexLocker locker( mSharedDS ? &mSharedDS->mutex() : nullptr );
+
   feature.setValid( false );
 
   if ( mClosed || !mOgrLayer )
@@ -286,6 +302,8 @@ bool QgsOgrFeatureIterator::fetchFeature( QgsFeature &feature )
 
 bool QgsOgrFeatureIterator::rewind()
 {
+  QMutexLocker locker( mSharedDS ? &mSharedDS->mutex() : nullptr );
+
   if ( mClosed || !mOgrLayer )
     return false;
 
@@ -299,6 +317,20 @@ bool QgsOgrFeatureIterator::rewind()
 
 bool QgsOgrFeatureIterator::close()
 {
+  if ( mSharedDS )
+  {
+    iteratorClosed();
+
+    if ( mOgrLayer )
+    {
+      mSharedDS->releaseResultSet( mOgrLayer );
+      mOgrLayer = nullptr;
+    }
+    mSharedDS.reset();
+    mClosed = true;
+    return true;
+  }
+
   if ( !mConn )
     return false;
 
@@ -444,7 +476,12 @@ QgsOgrFeatureSource::QgsOgrFeatureSource( const QgsOgrProvider *p )
   , mDriverName( p->mGDALDriverName )
   , mCrs( p->crs() )
   , mWkbType( p->wkbType() )
+  , mSharedDS( nullptr )
 {
+  if ( p->mTransaction )
+  {
+    mSharedDS = p->mTransaction->sharedDS();
+  }
   for ( int i = ( p->mFirstFieldIsFid ) ? 1 : 0; i < mFields.size(); i++ )
     mFieldsWithoutFid.append( mFields.at( i ) );
   QgsOgrConnPool::instance()->ref( QgsOgrProviderUtils::connectionPoolId( mDataSource ) );

src/providers/ogr/qgsogrfeatureiterator.h

@@ -21,8 +21,12 @@
 
 #include <ogr_api.h>
 
+#include <memory>
+
 class QgsOgrFeatureIterator;
 class QgsOgrProvider;
+class QgsOgrDataset;
+using QgsOgrDatasetSharedPtr = std::shared_ptr< QgsOgrDataset>;
 
 class QgsOgrFeatureSource : public QgsAbstractFeatureSource
 {
@@ -45,6 +49,7 @@ class QgsOgrFeatureSource : public QgsAbstractFeatureSource
     QString mDriverName;
     QgsCoordinateReferenceSystem mCrs;
     QgsWkbTypes::Type mWkbType = QgsWkbTypes::Unknown;
+    QgsOgrDatasetSharedPtr mSharedDS = nullptr;
 
     friend class QgsOgrFeatureIterator;
     friend class QgsOgrExpressionCompiler;
@@ -87,6 +92,7 @@ class QgsOgrFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsOgr
 
     QgsRectangle mFilterRect;
     QgsCoordinateTransform mTransform;
+    QgsOgrDatasetSharedPtr mSharedDS = nullptr;
 
     bool fetchFeatureWithId( QgsFeatureId id, QgsFeature &feature ) const;
 };