Fetch more in the model

qgis · Jul 6, 2021 · eea1eb4 · eea1eb4
1 parent 2c9662b
commit eea1eb4
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Showing 7 changed files with 184 additions and 144 deletions.
diff --git a/python/core/auto_generated/qgsqueryresultmodel.sip.in b/python/core/auto_generated/qgsqueryresultmodel.sip.in
@@ -44,6 +44,9 @@ Constructs a QgsQueryResultModel from a ``queryResult`` with optional ``parent``
     virtual QVariant headerData( int section, Qt::Orientation orientation, int role ) const;
 
 
+    void fetchMore( const QModelIndex &parent );
+    bool canFetchMore( const QModelIndex &parent ) const;
+
     QStringList columns() const;
 %Docstring
 Returns the column names
@@ -76,6 +79,10 @@ Cancels the row fetching.
 Emitted when all rows have been fetched or when the fetching has been stopped
 %End
 
+    void fetchMoreRows( qlonglong maxRows );
+
+    void fetchingStarted();
+
 };
 
 /************************************************************************

diff --git a/src/core/qgsqueryresultmodel.cpp b/src/core/qgsqueryresultmodel.cpp
@@ -23,10 +23,11 @@ QgsQueryResultModel::QgsQueryResultModel( const QgsAbstractDatabaseProviderConne
   qRegisterMetaType< QList<QList<QVariant>>>( "QList<QList<QVariant>>" );
   mWorker = std::make_unique<QgsQueryResultFetcher>( &mQueryResult );
   mWorker->moveToThread( &mWorkerThread );
-  connect( &mWorkerThread, &QThread::started, mWorker.get(), &QgsQueryResultFetcher::fetchRows );
+  //connect( &mWorkerThread, &QThread::started, mWorker.get(), [ = ] () { mWorker->fetchRows( 1000 ); }, Qt::ConnectionType::QueuedConnection );
   // Forward signals to the model
   connect( mWorker.get(), &QgsQueryResultFetcher::rowsReady, this, &QgsQueryResultModel::rowsReady );
   connect( mWorker.get(), &QgsQueryResultFetcher::fetchingComplete, this, &QgsQueryResultModel::fetchingComplete );
+  connect( this, &QgsQueryResultModel::fetchMoreRows, mWorker.get(), &QgsQueryResultFetcher::fetchRows );
   mWorkerThread.start();
   if ( mQueryResult.rowCount() > 0 )
   {
@@ -41,6 +42,24 @@ void QgsQueryResultModel::rowsReady( const QList<QList<QVariant>> &rows )
   endInsertRows();
 }
 
+
+bool QgsQueryResultModel::canFetchMore( const QModelIndex &parent ) const
+{
+  if ( parent.isValid() )
+    return false;
+  return mQueryResult.rowCount() < 0 || mRows.length() < mQueryResult.rowCount();
+}
+
+
+void QgsQueryResultModel::fetchMore( const QModelIndex &parent )
+{
+  if ( ! parent.isValid() )
+  {
+    emit fetchingStarted();
+    emit fetchMoreRows( 1000 );
+  }
+}
+
 void QgsQueryResultModel::cancel()
 {
   if ( mWorker )
@@ -121,11 +140,12 @@ QVariant QgsQueryResultModel::headerData( int section, Qt::Orientation orientati
 
 const int QgsQueryResultFetcher::ROWS_TO_FETCH = 200;
 
-void QgsQueryResultFetcher::fetchRows()
+void QgsQueryResultFetcher::fetchRows( qlonglong maxRows )
 {
   qlonglong rowCount { 0 };
   QList<QList<QVariant>> newRows;
-  while ( mStopFetching == 0 && mQueryResult->hasNextRow() )
+  newRows.reserve( ROWS_TO_FETCH );
+  while ( mStopFetching == 0 && mQueryResult->hasNextRow() && ( maxRows < 0 || rowCount < maxRows ) )
   {
     newRows.append( mQueryResult->nextRow() );
     ++rowCount;

diff --git a/src/core/qgsqueryresultmodel.h b/src/core/qgsqueryresultmodel.h
@@ -43,8 +43,8 @@ class QgsQueryResultFetcher: public QObject
       : mQueryResult( queryResult )
     {}
 
-    //! Start fetching
-    void fetchRows();
+    //! Start fetching at most \a maxRows, default value of -1 fetches all rows.
+    void fetchRows( qlonglong maxRows = -1 );
 
     //! Stop fetching
     void stopFetching();
@@ -97,6 +97,9 @@ class CORE_EXPORT QgsQueryResultModel : public QAbstractTableModel
     QVariant data( const QModelIndex &index, int role ) const override;
     QVariant headerData( int section, Qt::Orientation orientation, int role ) const override;
 
+    void fetchMore( const QModelIndex &parent );
+    bool canFetchMore( const QModelIndex &parent ) const;
+
     //! Returns the column names
     QStringList columns() const;
 
@@ -124,6 +127,10 @@ class CORE_EXPORT QgsQueryResultModel : public QAbstractTableModel
     //! Emitted when all rows have been fetched or when the fetching has been stopped
     void fetchingComplete();
 
+    void fetchMoreRows( qlonglong maxRows );
+
+    void fetchingStarted();
+
   private:
 
     QgsAbstractDatabaseProviderConnection::QueryResult mQueryResult;

diff --git a/src/gui/qgsqueryresultwidget.cpp b/src/gui/qgsqueryresultwidget.cpp
@@ -241,13 +241,27 @@ void QgsQueryResultWidget::startFetching()
     }
     else
     {
+      if ( mQueryResultWatcher.result().rowCount() > 0 )
+      {
+        mStatusLabel->setText( QStringLiteral( "Query executed successfully (%1 rows)" ).arg( QLocale().toString( mQueryResultWatcher.result().rowCount() ) ) );
+      }
+      else
+      {
+        mStatusLabel->setText( QStringLiteral( "Query executed successfully" ) );
+      }
       mModel = std::make_unique<QgsQueryResultModel>( mQueryResultWatcher.result() );
       connect( mFeedback.get(), &QgsFeedback::canceled, mModel.get(), [ = ]
       {
         mModel->cancel();
         mWasCanceled = true;
       } );
 
+
+      connect( mModel.get(), &QgsQueryResultModel::fetchingStarted, this, [ = ]
+      {
+        mProgressBar->show();
+      } );
+
       connect( mModel.get(), &QgsQueryResultModel::rowsInserted, this, [ = ]( const QModelIndex &, int, int )
       {
         if ( ! mFirstRowFetched )
@@ -263,8 +277,9 @@ void QgsQueryResultWidget::startFetching()
             mProgressBar->setRange( 0, mActualRowCount );
           }
         }
-        mStatusLabel->setText( tr( "Fetched rows: %1 %2" )
-                               .arg( mModel->rowCount( mModel->index( -1, -1 ) ) )
+        mStatusLabel->setText( tr( "Fetched rows: %1/%2 %3" )
+                               .arg( QLocale().toString( mModel->rowCount( mModel->index( -1, -1 ) ) ) )
+                               .arg( mActualRowCount != -1 ? QLocale().toString( mActualRowCount ) : tr( "unknown" ) )
                                .arg( mWasCanceled ? tr( "(stopped)" ) : QString() ) );
         if ( mActualRowCount != -1 )
         {
@@ -278,25 +293,20 @@ void QgsQueryResultWidget::startFetching()
       connect( mModel.get(), &QgsQueryResultModel::fetchingComplete, mStopButton, [ = ]
       {
         mStopButton->setEnabled( false );
-        if ( ! mWasCanceled )
-        {
-          mStatusLabel->setText( "Query executed successfully." );
-          mProgressBar->hide();
-        }
       } );
     }
   }
   else
   {
-    mStatusLabel->setText( tr( "SQL command aborted." ) );
+    mStatusLabel->setText( tr( "SQL command aborted" ) );
     mProgressBar->hide();
   }
 }
 
 void QgsQueryResultWidget::showError( const QString &title, const QString &message, bool isSqlError )
 {
   mStatusLabel->show();
-  mStatusLabel->setText( tr( "There was an error executing the query." ) );
+  mStatusLabel->setText( tr( "An error occurred while executing the query" ) );
   mProgressBar->hide();
   mQueryResultsTableView->hide();
   if ( isSqlError )

diff --git a/src/providers/postgres/qgspostgresconn.h b/src/providers/postgres/qgspostgresconn.h
@@ -212,6 +212,10 @@ class QgsPostgresConn : public QObject
      */
     static QgsPostgresConn *connectDb( const QString &connInfo, bool readOnly, bool shared = true, bool transaction = false );
 
+
+    QgsPostgresConn( const QString &conninfo, bool readOnly, bool shared, bool transaction );
+    ~QgsPostgresConn() override;
+
     void ref();
     void unref();
 
@@ -403,8 +407,6 @@ class QgsPostgresConn : public QObject
     void unlock() { mLock.unlock(); }
 
   private:
-    QgsPostgresConn( const QString &conninfo, bool readOnly, bool shared, bool transaction );
-    ~QgsPostgresConn() override;
 
     int mRef;
     int mOpenCursors;