Re-implement dropping of files on folders in the Places Panel.

This resolves a regression caused by the Places Panel rewrite. There is
a small glitch left when reordering items (dragging below the last or
above the first item only shows the drop indicator when first dragging
out of the item and then back), but I prefer not to fix this glitch
right now because this would require a more intrusive change, and I do
not want to risk regressions because is not much time left to fix them
before 4.9.0 is released.

Thanks to Peter Penz for providing some advice about this issue.

BUG: 302557
FIXED-IN: 4.9.0
(cherry picked from commit f4c960025167b7c7e04e1290ac9d9fee03a9b62d)

5 files changed, 31 insertions, 3 deletions

diff --git a/src/panels/places/placesitemlistwidget.cpp b/src/panels/places/placesitemlistwidget.cpp
index 3f4c92dfa..24c2b3f11 100644
--- a/src/panels/places/placesitemlistwidget.cpp
+++ b/src/panels/places/placesitemlistwidget.cpp
@@ -19,6 +19,8 @@
 
 #include "placesitemlistwidget.h"
 
+#include "kdebug.h"
+
 PlacesItemListWidget::PlacesItemListWidget(KItemListWidgetInformant* informant, QGraphicsItem* parent) :
     KStandardItemListWidget(informant, parent)
 {
diff --git a/src/panels/places/placesitemmodel.cpp b/src/panels/places/placesitemmodel.cpp
index 00ab9670b..497901345 100644
--- a/src/panels/places/placesitemmodel.cpp
+++ b/src/panels/places/placesitemmodel.cpp
@@ -396,7 +396,12 @@ QMimeData* PlacesItemModel::createMimeData(const QSet<int>& indexes) const
     return mimeData;
 }
 
-void PlacesItemModel::dropMimeData(int index, const QMimeData* mimeData)
+bool PlacesItemModel::supportsDropping(int index) const
+{
+    return index >= 0 && index < count();
+}
+
+void PlacesItemModel::dropMimeDataBefore(int index, const QMimeData* mimeData)
 {
     if (mimeData->hasFormat(internalMimeType())) {
         // The item has been moved inside the view
diff --git a/src/panels/places/placesitemmodel.h b/src/panels/places/placesitemmodel.h
index a060f4549..463e564e3 100644
--- a/src/panels/places/placesitemmodel.h
+++ b/src/panels/places/placesitemmodel.h
@@ -120,7 +120,10 @@ public:
     /** @reimp */
     virtual QMimeData* createMimeData(const QSet<int>& indexes) const;
 
-    void dropMimeData(int index, const QMimeData* mimeData);
+    /** @reimp */
+    virtual bool supportsDropping(int index) const;
+
+    void dropMimeDataBefore(int index, const QMimeData* mimeData);
 
     /**
      * @return Converts the URL, which contains "virtual" URLs for system-items like
diff --git a/src/panels/places/placespanel.cpp b/src/panels/places/placespanel.cpp
index 64de516fa..429c5399a 100644
--- a/src/panels/places/placespanel.cpp
+++ b/src/panels/places/placespanel.cpp
@@ -93,6 +93,7 @@ void PlacesPanel::showEvent(QShowEvent* event)
         connect(m_controller, SIGNAL(itemContextMenuRequested(int,QPointF)), this, SLOT(slotItemContextMenuRequested(int,QPointF)));
         connect(m_controller, SIGNAL(viewContextMenuRequested(QPointF)), this, SLOT(slotViewContextMenuRequested(QPointF)));
         connect(m_controller, SIGNAL(itemDropEvent(int,QGraphicsSceneDragDropEvent*)), this, SLOT(slotItemDropEvent(int,QGraphicsSceneDragDropEvent*)));
+        connect(m_controller, SIGNAL(aboveItemDropEvent(int,QGraphicsSceneDragDropEvent*)), this, SLOT(slotAboveItemDropEvent(int,QGraphicsSceneDragDropEvent*)));
 
         KItemListContainer* container = new KItemListContainer(m_controller, this);
         container->setEnabledFrame(false);
@@ -253,7 +254,23 @@ void PlacesPanel::slotViewContextMenuRequested(const QPointF& pos)
 
 void PlacesPanel::slotItemDropEvent(int index, QGraphicsSceneDragDropEvent* event)
 {
-    m_model->dropMimeData(index, event->mimeData());
+    if (index < 0) {
+        return;
+    }
+
+    KUrl destUrl = m_model->placesItem(index)->url();
+    QDropEvent dropEvent(event->pos().toPoint(),
+                         event->possibleActions(),
+                         event->mimeData(),
+                         event->buttons(),
+                         event->modifiers());
+
+    DragAndDropHelper::dropUrls(KFileItem(), destUrl, &dropEvent);
+}
+
+void PlacesPanel::slotAboveItemDropEvent(int index, QGraphicsSceneDragDropEvent* event)
+{
+    m_model->dropMimeDataBefore(index, event->mimeData());
 }
 
 void PlacesPanel::slotUrlsDropped(const KUrl& dest, QDropEvent* event, QWidget* parent)
diff --git a/src/panels/places/placespanel.h b/src/panels/places/placespanel.h
index 427b01248..8a84e00a0 100644
--- a/src/panels/places/placespanel.h
+++ b/src/panels/places/placespanel.h
@@ -56,6 +56,7 @@ private slots:
     void slotItemContextMenuRequested(int index, const QPointF& pos);
     void slotViewContextMenuRequested(const QPointF& pos);
     void slotItemDropEvent(int index, QGraphicsSceneDragDropEvent* event);
+    void slotAboveItemDropEvent(int index, QGraphicsSceneDragDropEvent* event);
     void slotUrlsDropped(const KUrl& dest, QDropEvent* event, QWidget* parent);
     void slotTrashUpdated(KJob* job);
     void slotStorageSetupDone(int index, bool success);