3 files changed, 104 insertions, 1 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoadrag.h b/src/plugins/platforms/cocoa/qcocoadrag.h
index 5a5b985c6e..975741c270 100644
--- a/src/plugins/platforms/cocoa/qcocoadrag.h
+++ b/src/plugins/platforms/cocoa/qcocoadrag.h
@@ -48,6 +48,8 @@
 #include <QtGui/private/qdnd_p.h>
 #include <QtGui/private/qinternalmimedata_p.h>
 
+#include <QtCore/qeventloop.h>
+
 QT_BEGIN_NAMESPACE
 
 class QCocoaDrag : public QPlatformDrag
@@ -69,11 +71,15 @@ public:
     void setLastMouseEvent(NSEvent *event, NSView *view);
 
     void setAcceptedAction(Qt::DropAction act);
+    void exitDragLoop();
 private:
     QDrag *m_drag;
     NSEvent *m_lastEvent;
     NSView *m_lastView;
     Qt::DropAction m_executed_drop_action;
+    QEventLoop internalDragLoop;
+
+    bool maybeDragMultipleItems();
 
     QPixmap dragPixmap(QDrag *drag, QPoint &hotSpot) const;
 };
diff --git a/src/plugins/platforms/cocoa/qcocoadrag.mm b/src/plugins/platforms/cocoa/qcocoadrag.mm
index 3525fddfd1..cf48c50caf 100644
--- a/src/plugins/platforms/cocoa/qcocoadrag.mm
+++ b/src/plugins/platforms/cocoa/qcocoadrag.mm
@@ -41,6 +41,9 @@
 #include "qmacclipboard.h"
 #include "qcocoahelpers.h"
 #include <QtGui/private/qcoregraphics_p.h>
+#include <QtCore/qsysinfo.h>
+
+#include <vector>
 
 QT_BEGIN_NAMESPACE
 
@@ -125,6 +128,9 @@ Qt::DropAction QCocoaDrag::drag(QDrag *o)
     m_drag = o;
     m_executed_drop_action = Qt::IgnoreAction;
 
+    if (maybeDragMultipleItems())
+        return m_executed_drop_action;
+
     QPoint hotSpot = m_drag->hotSpot();
     QPixmap pm = dragPixmap(m_drag, hotSpot);
     NSImage *dragImage = [NSImage imageFromQImage:pm.toImage()];
@@ -155,11 +161,95 @@ Qt::DropAction QCocoaDrag::drag(QDrag *o)
     return m_executed_drop_action;
 }
 
+bool QCocoaDrag::maybeDragMultipleItems()
+{
+    Q_ASSERT(m_drag && m_drag->mimeData());
+    Q_ASSERT(m_executed_drop_action == Qt::IgnoreAction);
+
+    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::MacOSMojave) {
+        // -dragImage: stopped working in 10.14 first.
+        return false;
+    }
+
+    const QMacAutoReleasePool pool;
+
+    NSWindow *theWindow = [m_lastEvent window];
+    Q_ASSERT(theWindow);
+
+    if (![theWindow.contentView respondsToSelector:@selector(draggingSession:sourceOperationMaskForDraggingContext:)])
+        return false;
+
+    auto *sourceView = static_cast<NSView<NSDraggingSource>*>(theWindow.contentView);
+
+    const auto &qtUrls = m_drag->mimeData()->urls();
+    NSPasteboard *dragBoard = [NSPasteboard pasteboardWithName:NSPasteboardNameDrag];
+
+    if (int(dragBoard.pasteboardItems.count) == 1 && qtUrls.size() <= 1) {
+        // Good old -dragImage: works perfectly for this ...
+        return false;
+    }
+
+    std::vector<NSPasteboardItem *> nonUrls;
+    for (NSPasteboardItem *item in dragBoard.pasteboardItems) {
+        bool isUrl = false;
+        for (NSPasteboardType type in item.types) {
+            using NSStringRef = NSString *;
+            if ([type isEqualToString:NSStringRef(kUTTypeFileURL)]) {
+                isUrl = true;
+                break;
+            }
+        }
+
+        if (!isUrl)
+            nonUrls.push_back(item);
+    }
+
+    QPoint hotSpot = m_drag->hotSpot();
+    const auto pixmap = dragPixmap(m_drag, hotSpot);
+    NSImage *dragImage = [NSImage imageFromQImage:pixmap.toImage()];
+    Q_ASSERT(dragImage);
+
+    NSMutableArray<NSDraggingItem *> *dragItems = [[[NSMutableArray alloc] init] autorelease];
+    const NSPoint itemLocation = m_drag->hotSpot().toCGPoint();
+    // 0. We start from URLs, which can be actually in a list (thus technically
+    // only ONE item in the pasteboard. The fact it's only one does not help, we are
+    // still getting an exception because of the number of items/images mismatch ...
+    for (const auto &qtUrl : qtUrls) {
+        NSURL *nsUrl = qtUrl.toNSURL();
+        auto *newItem = [[[NSDraggingItem alloc] initWithPasteboardWriter:nsUrl] autorelease];
+        const NSRect itemFrame = NSMakeRect(itemLocation.x, itemLocation.y,
+                                            dragImage.size.width,
+                                            dragImage.size.height);
+        [newItem setDraggingFrame:itemFrame contents:dragImage];
+        [dragItems addObject:newItem];
+    }
+    // 1. Repeat for non-url items, if any:
+    for (auto *pbItem : nonUrls) {
+        auto *newItem = [[[NSDraggingItem alloc] initWithPasteboardWriter:pbItem] autorelease];
+        const NSRect itemFrame = NSMakeRect(itemLocation.x, itemLocation.y,
+                                            dragImage.size.width,
+                                            dragImage.size.height);
+        [newItem setDraggingFrame:itemFrame contents:dragImage];
+        [dragItems addObject:newItem];
+    }
+
+    [sourceView beginDraggingSessionWithItems:dragItems event:m_lastEvent source:sourceView];
+    internalDragLoop.exec();
+    return true;
+}
+
 void QCocoaDrag::setAcceptedAction(Qt::DropAction act)
 {
     m_executed_drop_action = act;
 }
 
+void QCocoaDrag::exitDragLoop()
+{
+    if (internalDragLoop.isRunning())
+        internalDragLoop.exit();
+}
+
+
 QPixmap QCocoaDrag::dragPixmap(QDrag *drag, QPoint &hotSpot) const
 {
     const QMimeData* data = drag->mimeData();
diff --git a/src/plugins/platforms/cocoa/qnsview_dragging.mm b/src/plugins/platforms/cocoa/qnsview_dragging.mm
index 2e88b6a08f..44ffc87f7a 100644
--- a/src/plugins/platforms/cocoa/qnsview_dragging.mm
+++ b/src/plugins/platforms/cocoa/qnsview_dragging.mm
@@ -231,6 +231,10 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
     if (!target)
         return;
 
+    auto *nativeDrag = QCocoaIntegration::instance()->drag();
+    Q_ASSERT(nativeDrag);
+    nativeDrag->exitDragLoop();
+
     QPoint windowPoint = QPointF::fromCGPoint([self convertPoint:sender.draggingLocation fromView:nil]).toPoint();
 
     qCDebug(lcQpaMouse) << QEvent::DragLeave << self << "at" << windowPoint;
@@ -289,7 +293,10 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
     if (!target)
         return;
 
-    QCocoaIntegration::instance()->drag();
+    QCocoaDrag* nativeDrag = QCocoaIntegration::instance()->drag();
+    Q_ASSERT(nativeDrag);
+    nativeDrag->exitDragLoop();
+    nativeDrag->setAcceptedAction(qt_mac_mapNSDragOperation(operation));
 
     // Qt starts drag-and-drop on a mouse button press event. Cococa in
     // this case won't send the matching release event, so we have to