[FEATURE] Oracle: local cache of the list of tables

Caching is done using SQLite database (could be shared also with other providers)

src/providers/oracle/CMakeLists.txt

@@ -9,6 +9,7 @@ SET(ORACLE_SRCS
   qgsoracledataitems.cpp
   qgsoraclesourceselect.cpp
   qgsoraclenewconnection.cpp
+  qgsoracletablecache.cpp
   qgsoracletablemodel.cpp
   qgsoraclecolumntypethread.cpp
   qgsoraclefeatureiterator.cpp
@@ -20,6 +21,7 @@ SET(ORACLE_MOC_HDRS
   qgsoracledataitems.h
   qgsoraclesourceselect.h
   qgsoraclenewconnection.h
+  qgsoracletablecache.h
   qgsoracletablemodel.h
   qgsoraclecolumntypethread.h
 )

src/providers/oracle/qgsoraclecolumntypethread.cpp

@@ -37,16 +37,17 @@ void QgsOracleColumnTypeThread::stop()
 
 void QgsOracleColumnTypeThread::run()
 {
+  mStopped = false;
+
   QgsDataSourceURI uri = QgsOracleConn::connUri( mName );
   QgsOracleConn *conn = QgsOracleConn::connectDb( uri.connectionInfo() );
   if ( !conn )
   {
     QgsDebugMsg( "Connection failed - " + uri.connectionInfo() );
+    mStopped = true;
     return;
   }
 
-  mStopped = false;
-
   emit progressMessage( tr( "Retrieving tables of %1..." ).arg( mName ) );
   QVector<QgsOracleLayerProperty> layerProperties;
   if ( !conn->supportedLayers( layerProperties,
@@ -84,6 +85,10 @@ void QgsOracleColumnTypeThread::run()
     emit setLayerType( layerProperty );
   }
 
+  // store the list for later use (cache)
+  if ( !mStopped )
+    mLayerProperties = layerProperties;
+
   emit progress( 0, 0 );
   emit progressMessage( tr( "Table retrieval finished." ) );
 

src/providers/oracle/qgsoraclecolumntypethread.h

@@ -36,6 +36,12 @@ class QgsOracleColumnTypeThread : public QThread
     // by emitting the setLayerType() signal.
     virtual void run();
 
+    bool isStopped() const { return mStopped; }
+    QVector<QgsOracleLayerProperty> layerProperties() const { return mLayerProperties; }
+    QString connectionName() const { return mName; }
+    bool useEstimatedMetadata() const { return mUseEstimatedMetadata; }
+    bool allowGeometrylessTables() const { return mAllowGeometrylessTables; }
+
   signals:
     void setLayerType( QgsOracleLayerProperty layerProperty );
     void progress( int, int );
@@ -51,7 +57,7 @@ class QgsOracleColumnTypeThread : public QThread
     bool mUseEstimatedMetadata;
     bool mAllowGeometrylessTables;
     bool mStopped;
-    QList<QgsOracleLayerProperty> layerProperties;
+    QVector<QgsOracleLayerProperty> mLayerProperties;
 };
 
 #endif // QGSORACLECOLUMNTYPETHREAD_H

src/providers/oracle/qgsoracleconn.h

@@ -47,6 +47,13 @@ struct QgsOracleLayerProperty
 
   int size() const { Q_ASSERT( types.size() == srids.size() ); return types.size(); }
 
+  bool operator==( const QgsOracleLayerProperty& other )
+  {
+    return types == other.types && srids == other.srids && ownerName == other.ownerName &&
+           tableName == other.tableName && geometryColName == other.geometryColName &&
+           isView == other.isView && pkCols == other.pkCols && sql == other.sql;
+  }
+
   QgsOracleLayerProperty at( int i ) const
   {
     QgsOracleLayerProperty property;

src/providers/oracle/qgsoraclenewconnection.h

@@ -32,6 +32,10 @@ class QgsOracleNewConnection : public QDialog, private Ui::QgsOracleNewConnectio
     QgsOracleNewConnection( QWidget *parent = 0, const QString& connName = QString::null, Qt::WindowFlags fl = QgisGui::ModalDialogFlags );
     //! Destructor
     ~QgsOracleNewConnection();
+
+    QString originalConnName() const { return mOriginalConnName; }
+    QString connName() const { return txtName->text(); }
+
   public slots:
     void accept();
     void on_btnConnect_clicked();

src/providers/oracle/qgsoraclesourceselect.cpp

@@ -23,6 +23,7 @@ email                : jef at norbit dot de
 #include "qgscontexthelp.h"
 #include "qgsoracleprovider.h"
 #include "qgsoraclenewconnection.h"
+#include "qgsoracletablecache.h"
 #include "qgsmanageconnectionsdialog.h"
 #include "qgsquerybuilder.h"
 #include "qgsdatasourceuri.h"
@@ -79,7 +80,8 @@ QWidget *QgsOracleSourceSelectDelegate::createEditor( QWidget *parent, const QSt
     if ( values.size() == 0 )
     {
       QString ownerName = index.sibling( index.row(), QgsOracleTableModel::dbtmOwner ).data( Qt::DisplayRole ).toString();
-      values = mConn->pkCandidates( ownerName, tableName );
+      if ( conn() )
+        values = conn()->pkCandidates( ownerName, tableName );
     }
 
     if ( values.size() == 0 )
@@ -198,8 +200,6 @@ QgsOracleSourceSelect::QgsOracleSourceSelect( QWidget *parent, Qt::WindowFlags f
     connect( mBuildQueryButton, SIGNAL( clicked() ), this, SLOT( buildQuery() ) );
   }
 
-  populateConnectionList();
-
   mSearchModeComboBox->addItem( tr( "Wildcard" ) );
   mSearchModeComboBox->addItem( tr( "RegExp" ) );
 
@@ -251,6 +251,8 @@ QgsOracleSourceSelect::QgsOracleSourceSelect( QWidget *parent, Qt::WindowFlags f
   mSearchModeComboBox->setVisible( false );
   mSearchModeLabel->setVisible( false );
   mSearchTableEdit->setVisible( false );
+
+  populateConnectionList();
 }
 /** Autoconnected SLOTS **/
 // Slot for adding a new connection
@@ -274,6 +276,8 @@ void QgsOracleSourceSelect::on_btnDelete_clicked()
 
   QgsOracleConn::deleteConnection( cmbConnections->currentText() );
 
+  QgsOracleTableCache::removeFromCache( cmbConnections->currentText() );
+
   populateConnectionList();
   emit connectionsChanged();
 }
@@ -304,6 +308,9 @@ void QgsOracleSourceSelect::on_btnEdit_clicked()
   QgsOracleNewConnection *nc = new QgsOracleNewConnection( this, cmbConnections->currentText() );
   if ( nc->exec() )
   {
+    if ( nc->connName() != nc->originalConnName() )
+      QgsOracleTableCache::renameConnectionInCache( nc->originalConnName(), nc->connName() );
+
     populateConnectionList();
     emit connectionsChanged();
   }
@@ -321,6 +328,15 @@ void QgsOracleSourceSelect::on_cmbConnections_currentIndexChanged( const QString
   cbxAllowGeometrylessTables->blockSignals( true );
   cbxAllowGeometrylessTables->setChecked( QgsOracleConn::allowGeometrylessTables( text ) );
   cbxAllowGeometrylessTables->blockSignals( false );
+
+  // populate the table list
+  QgsDataSourceURI uri = QgsOracleConn::connUri( cmbConnections->currentText() );
+  mConnInfo = uri.connectionInfo();
+  mUseEstimatedMetadata = uri.useEstimatedMetadata();
+
+  QgsDebugMsg( "Connection info: " + uri.connectionInfo() );
+
+  loadTableFromCache();
 }
 
 void QgsOracleSourceSelect::on_cbxAllowGeometrylessTables_stateChanged( int )
@@ -452,6 +468,8 @@ void QgsOracleSourceSelect::populateConnectionList()
   btnDelete->setDisabled( cmbConnections->count() == 0 );
   btnConnect->setDisabled( cmbConnections->count() == 0 );
   cmbConnections->setDisabled( cmbConnections->count() == 0 );
+
+  on_cmbConnections_currentIndexChanged( cmbConnections->currentText() );
 }
 
 // Slot for performing action when the Add button is clicked
@@ -498,18 +516,12 @@ void QgsOracleSourceSelect::on_btnConnect_clicked()
   QModelIndex rootItemIndex = mTableModel.indexFromItem( mTableModel.invisibleRootItem() );
   mTableModel.removeRows( 0, mTableModel.rowCount( rootItemIndex ), rootItemIndex );
 
-  // populate the table list
-  QgsDataSourceURI uri = QgsOracleConn::connUri( cmbConnections->currentText() );
-
-  QgsDebugMsg( "Connection info: " + uri.connectionInfo() );
-
-  mConnInfo = uri.connectionInfo();
-  mUseEstimatedMetadata = uri.useEstimatedMetadata();
-
   QApplication::setOverrideCursor( Qt::BusyCursor );
 
+  QgsDataSourceURI uri = QgsOracleConn::connUri( cmbConnections->currentText() );
+
   mIsConnected = true;
-  mTablesTreeDelegate->setConn( QgsOracleConn::connectDb( uri.connectionInfo() ) );
+  mTablesTreeDelegate->setConnectionInfo( uri.connectionInfo() );
 
   mColumnTypeThread = new QgsOracleColumnTypeThread( cmbConnections->currentText(),
       mUseEstimatedMetadata,
@@ -544,8 +556,31 @@ void QgsOracleSourceSelect::finishList()
   mTablesTreeView->sortByColumn( QgsOracleTableModel::dbtmOwner, Qt::AscendingOrder );
 }
 
+static QgsOracleTableCache::CacheFlags _currentFlags( QString connName, bool useEstimatedMetadata, bool allowGeometrylessTables )
+{
+  QgsOracleTableCache::CacheFlags flags;
+  if ( QgsOracleConn::geometryColumnsOnly( connName ) )
+    flags |= QgsOracleTableCache::OnlyLookIntoMetadataTable;
+  if ( QgsOracleConn::userTablesOnly( connName ) )
+    flags |= QgsOracleTableCache::OnlyLookForUserTables;
+  if ( QgsOracleConn::onlyExistingTypes( connName ) )
+    flags |= QgsOracleTableCache::OnlyExistingGeometryTypes;
+  if ( useEstimatedMetadata )
+    flags |= QgsOracleTableCache::UseEstimatedTableMetadata;
+  if ( allowGeometrylessTables )
+    flags |= QgsOracleTableCache::AllowGeometrylessTables;
+  return flags;
+}
+
 void QgsOracleSourceSelect::columnThreadFinished()
 {
+  if ( !mColumnTypeThread->isStopped() )
+  {
+    QString connName = mColumnTypeThread->connectionName();
+    QgsOracleTableCache::CacheFlags flags = _currentFlags( connName, mColumnTypeThread->useEstimatedMetadata(), mColumnTypeThread->allowGeometrylessTables() );
+    QgsOracleTableCache::saveToCache( connName, flags, mColumnTypeThread->layerProperties() );
+  }
+
   delete mColumnTypeThread;
   mColumnTypeThread = 0;
   btnConnect->setText( tr( "Connect" ) );
@@ -628,3 +663,26 @@ void QgsOracleSourceSelect::setSearchExpression( const QString& regexp )
 {
   Q_UNUSED( regexp );
 }
+
+void QgsOracleSourceSelect::loadTableFromCache()
+{
+  QModelIndex rootItemIndex = mTableModel.indexFromItem( mTableModel.invisibleRootItem() );
+  mTableModel.removeRows( 0, mTableModel.rowCount( rootItemIndex ), rootItemIndex );
+
+  QString connName = cmbConnections->currentText();
+  QVector<QgsOracleLayerProperty> layers;
+  if ( !QgsOracleTableCache::loadFromCache( connName, _currentFlags( connName, mUseEstimatedMetadata, cbxAllowGeometrylessTables->isChecked() ), layers ) )
+    return;
+
+  foreach ( const QgsOracleLayerProperty& layerProperty, layers )
+    mTableModel.addTableEntry( layerProperty );
+
+  QApplication::setOverrideCursor( Qt::BusyCursor );
+
+  QgsDataSourceURI uri = QgsOracleConn::connUri( connName );
+
+  mIsConnected = true;
+  mTablesTreeDelegate->setConnectionInfo( uri.connectionInfo() );
+
+  finishList();
+}

src/providers/oracle/qgsoraclesourceselect.h

@@ -53,10 +53,22 @@ class QgsOracleSourceSelectDelegate : public QItemDelegate
     void setModelData( QWidget *editor, QAbstractItemModel *model, const QModelIndex &index ) const;
     void setEditorData( QWidget *editor, const QModelIndex &index ) const;
 
-    void setConn( QgsOracleConn *conn ) { if ( mConn ) mConn->disconnect();  mConn = conn; }
+    void setConnectionInfo( const QString& connInfo ) { mConnInfo = connInfo; }
+
+  protected:
+    void setConn( QgsOracleConn *conn ) const { if ( mConn ) mConn->disconnect();  mConn = conn; }
+
+    QgsOracleConn* conn() const
+    {
+      if ( !mConn )
+        setConn( QgsOracleConn::connectDb( mConnInfo ) );
+      return mConn;
+    }
 
   private:
-    QgsOracleConn *mConn;
+    QString mConnInfo;
+    //! lazily initialized connection (to detect possible primary keys)
+    mutable QgsOracleConn *mConn;
 };
 
 
@@ -136,6 +148,9 @@ class QgsOracleSourceSelect : public QDialog, private Ui::QgsDbSourceSelectBase
     //! Embedded mode, without 'Close'
     bool mEmbeddedMode;
 
+    //! try to load list of tables from local cache
+    void loadTableFromCache();
+
     // queue another query for the thread
     void addSearchGeometryColumn( QgsOracleLayerProperty layerProperty );