Don't allow undo/redo while dragging a clip in timeline.

Related to #264

src/mainwindow.cpp

@@ -1408,10 +1408,22 @@ void MainWindow::setupActions()
     QAction *undo = KStandardAction::undo(m_commandStack, SLOT(undo()), actionCollection());
     undo->setEnabled(false);
     connect(m_commandStack, &QUndoGroup::canUndoChanged, undo, &QAction::setEnabled);
+    connect(this, &MainWindow::enableUndo, [this, undo] (bool enable) {
+        if (enable) {
+            enable = m_commandStack->activeStack()->canUndo();
+        }
+        undo->setEnabled(enable);
+    });
 
     QAction *redo = KStandardAction::redo(m_commandStack, SLOT(redo()), actionCollection());
     redo->setEnabled(false);
     connect(m_commandStack, &QUndoGroup::canRedoChanged, redo, &QAction::setEnabled);
+    connect(this, &MainWindow::enableUndo, [this, redo] (bool enable) {
+        if (enable) {
+            enable = m_commandStack->activeStack()->canRedo();
+        }
+        redo->setEnabled(enable);
+    });
 
     auto *addClips = new QMenu(this);
 

src/mainwindow.h

@@ -484,6 +484,8 @@ signals:
     /** @brief Clear asset view if itemId is displayed. */
     void clearAssetPanel(int itemId = -1);
     void adjustAssetPanelRange(int itemId, int in, int out);
+    /** @brief Enable or disable the undo stack. For example undo/redo should not be enabled when dragging a clip in timeline or we risk corruption. */
+    void enableUndo(bool enable);
 };
 
 #endif

src/timeline2/view/qml/timeline.qml

@@ -16,11 +16,13 @@ Rectangle {
     color: activePalette.window
     property bool validMenu: false
     property color textColor: activePalette.text
+    property bool dragInProgress: dragProxyArea.pressed || dragProxyArea.drag.active
 
     signal clipClicked()
     signal mousePosChanged(int position)
     signal zoomIn(bool onMouse)
     signal zoomOut(bool onMouse)
+    signal processingDrag(bool dragging)
 
     FontMetrics {
         id: fontMetrics
@@ -33,6 +35,10 @@ Rectangle {
         id: compositionMenu
     }
 
+    onDragInProgressChanged: {
+        processingDrag(!root.dragInProgress)
+    }
+
     function fitZoom() {
         return scrollView.width / (timeline.duration * 1.1)
     }
@@ -164,7 +170,7 @@ Rectangle {
     }
 
     function isDragging() {
-        return dragProxy.draggedItem > -1 && dragProxyArea.pressed
+        return dragInProgress
     }
 
     function initDrag(itemObject, itemCoord, itemId, itemPos, itemTrack, isComposition) {

src/timeline2/view/timelinewidget.cpp

@@ -136,6 +136,7 @@ void TimelineWidget::setModel(const std::shared_ptr<TimelineItemModel> &model)
     connect(rootObject(), SIGNAL(mousePosChanged(int)), pCore->window(), SLOT(slotUpdateMousePosition(int)));
     connect(rootObject(), SIGNAL(zoomIn(bool)), pCore->window(), SLOT(slotZoomIn(bool)));
     connect(rootObject(), SIGNAL(zoomOut(bool)), pCore->window(), SLOT(slotZoomOut(bool)));
+    connect(rootObject(), SIGNAL(processingDrag(bool)), pCore->window(), SIGNAL(enableUndo(bool)));
     m_proxy->setRoot(rootObject());
     setVisible(true);
     loading = false;