macOS: Transition to new QPA dag-and-drop API

The new API allows us to pass the mouse buttons and
keyboard modifiers along with the QWSI event.

Task-number: QTBUG-57168
Change-Id: Ic54c012d1593d922e7dcd31facab2f2c630c7996
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

4 files changed, 105 insertions, 25 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoahelpers.h b/src/plugins/platforms/cocoa/qcocoahelpers.h
index 516eac0503..cf8a241db5 100644
--- a/src/plugins/platforms/cocoa/qcocoahelpers.h
+++ b/src/plugins/platforms/cocoa/qcocoahelpers.h
@@ -98,6 +98,12 @@ QPointF qt_mac_flip(const QPointF &pos, const QRectF &reference);
 QRectF qt_mac_flip(const QRectF &rect, const QRectF &reference);
 
 Qt::MouseButton cocoaButton2QtButton(NSInteger buttonNum);
+Qt::MouseButton cocoaButton2QtButton(NSEvent *event);
+
+QEvent::Type cocoaEvent2QtMouseEvent(NSEvent *event);
+
+Qt::MouseButtons cocoaMouseButtons2QtMouseButtons(NSInteger pressedMouseButtons);
+Qt::MouseButtons currentlyPressedMouseButtons();
 
 // strip out '&' characters, and convert "&&" to a single '&', in menu
 // text - since menu text is sometimes decorated with these for Windows
diff --git a/src/plugins/platforms/cocoa/qcocoahelpers.mm b/src/plugins/platforms/cocoa/qcocoahelpers.mm
index a1cf1bc632..12be222ab3 100644
--- a/src/plugins/platforms/cocoa/qcocoahelpers.mm
+++ b/src/plugins/platforms/cocoa/qcocoahelpers.mm
@@ -278,6 +278,77 @@ Qt::MouseButton cocoaButton2QtButton(NSInteger buttonNum)
     return Qt::NoButton;
 }
 
+/*!
+  \fn Qt::MouseButton cocoaButton2QtButton(NSEvent *event)
+
+  Returns the Qt::Button that corresponds to an NSEvent.buttonNumber.
+
+  \note AppKit will use buttonNumber 0 to indicate both "left button"
+  and "no button". Only NSEvents that describes mouse press/release/dragging
+  events (e.g NSEventTypeOtherMouseDown) will contain a valid
+  button number.
+*/
+Qt::MouseButton cocoaButton2QtButton(NSEvent *event)
+{
+    if (event.type == NSMouseMoved)
+        return Qt::NoButton;
+
+    return cocoaButton2QtButton(event.buttonNumber);
+}
+
+/*!
+  \fn QEvent::Type cocoaEvent2QtMouseEvent(NSEvent *event)
+
+  Returns the QEvent::Type that corresponds to an NSEvent.type.
+*/
+QEvent::Type cocoaEvent2QtMouseEvent(NSEvent *event)
+{
+    switch (event.type) {
+    case NSLeftMouseDown:
+    case NSRightMouseDown:
+    case NSOtherMouseDown:
+        return QEvent::MouseButtonPress;
+
+    case NSLeftMouseUp:
+    case NSRightMouseUp:
+    case NSOtherMouseUp:
+        return QEvent::MouseButtonRelease;
+
+    case NSLeftMouseDragged:
+    case NSRightMouseDragged:
+    case NSOtherMouseDragged:
+        return QEvent::MouseMove;
+
+    case NSMouseMoved:
+        return QEvent::MouseMove;
+
+    default:
+        break;
+    }
+
+    return QEvent::None;
+}
+
+/*!
+  \fn Qt::MouseButtons cocoaMouseButtons2QtMouseButtons(NSInteger pressedMouseButtons)
+
+  Returns the Qt::MouseButtons that corresponds to an NSEvent.pressedMouseButtons.
+*/
+Qt::MouseButtons cocoaMouseButtons2QtMouseButtons(NSInteger pressedMouseButtons)
+{
+  return static_cast<Qt::MouseButton>(pressedMouseButtons & Qt::MouseButtonMask);
+}
+
+/*!
+  \fn Qt::MouseButtons currentlyPressedMouseButtons()
+
+  Returns the Qt::MouseButtons that corresponds to an NSEvent.pressedMouseButtons.
+*/
+Qt::MouseButtons currentlyPressedMouseButtons()
+{
+  return cocoaMouseButtons2QtMouseButtons(NSEvent.pressedMouseButtons);
+}
+
 QString qt_mac_removeAmpersandEscapes(QString s)
 {
     return QPlatformTheme::removeMnemonics(s).trimmed();
diff --git a/src/plugins/platforms/cocoa/qnsview_dragging.mm b/src/plugins/platforms/cocoa/qnsview_dragging.mm
index e77a26eed0..01df0e9337 100644
--- a/src/plugins/platforms/cocoa/qnsview_dragging.mm
+++ b/src/plugins/platforms/cocoa/qnsview_dragging.mm
@@ -207,18 +207,21 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
     if (!target)
         return NSDragOperationNone;
 
-    // update these so selecting move/copy/link works
-    QGuiApplicationPrivate::modifier_buttons = [QNSView convertKeyModifiers: [[NSApp currentEvent] modifierFlags]];
+    const auto modifiers = [QNSView convertKeyModifiers:NSApp.currentEvent.modifierFlags];
+    const auto buttons = currentlyPressedMouseButtons();
+    const auto point = mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint);
 
     QPlatformDragQtResponse response(false, Qt::IgnoreAction, QRect());
     QCocoaDrag* nativeDrag = QCocoaIntegration::instance()->drag();
     if (nativeDrag->currentDrag()) {
         // The drag was started from within the application
-        response = QWindowSystemInterface::handleDrag(target, nativeDrag->dragMimeData(), mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint), qtAllowed);
+        response = QWindowSystemInterface::handleDrag(target, nativeDrag->dragMimeData(),
+                                                      point, qtAllowed, buttons, modifiers);
         [self updateCursorFromDragResponse:response drag:nativeDrag];
     } else {
         QCocoaDropData mimeData([sender draggingPasteboard]);
-        response = QWindowSystemInterface::handleDrag(target, &mimeData, mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint), qtAllowed);
+        response = QWindowSystemInterface::handleDrag(target, &mimeData,
+                                                      point, qtAllowed, buttons, modifiers);
     }
 
     return qt_mac_mapDropAction(response.acceptedAction());
@@ -237,7 +240,9 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
     QPoint qt_windowPoint(windowPoint.x, windowPoint.y);
 
     // Send 0 mime data to indicate drag exit
-    QWindowSystemInterface::handleDrag(target, 0, mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint), Qt::IgnoreAction);
+    QWindowSystemInterface::handleDrag(target, nullptr,
+                                       mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint),
+                                       Qt::IgnoreAction, Qt::NoButton, Qt::NoModifier);
 }
 
 // called on drop, send the drop to Qt and return if it was accepted.
@@ -256,12 +261,18 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
 
     QPlatformDropQtResponse response(false, Qt::IgnoreAction);
     QCocoaDrag* nativeDrag = QCocoaIntegration::instance()->drag();
+    const auto modifiers = [QNSView convertKeyModifiers:NSApp.currentEvent.modifierFlags];
+    const auto buttons = currentlyPressedMouseButtons();
+    const auto point = mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint);
+
     if (nativeDrag->currentDrag()) {
         // The drag was started from within the application
-        response = QWindowSystemInterface::handleDrop(target, nativeDrag->dragMimeData(), mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint), qtAllowed);
+        response = QWindowSystemInterface::handleDrop(target, nativeDrag->dragMimeData(),
+                                                      point, qtAllowed, buttons, modifiers);
     } else {
         QCocoaDropData mimeData([sender draggingPasteboard]);
-        response = QWindowSystemInterface::handleDrop(target, &mimeData, mapWindowCoordinates(m_platformWindow->window(), target, qt_windowPoint), qtAllowed);
+        response = QWindowSystemInterface::handleDrop(target, &mimeData,
+                                                      point, qtAllowed, buttons, modifiers);
     }
     return response.isAccepted();
 }
@@ -271,7 +282,7 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
               operation:(NSDragOperation)operation
 {
     Q_UNUSED(session);
-    Q_UNUSED(operation);
+    Q_UNUSED(screenPoint);
 
     if (!m_platformWindow)
         return;
@@ -283,20 +294,7 @@ static QPoint mapWindowCoordinates(QWindow *source, QWindow *target, QPoint poin
     QCocoaDrag* nativeDrag = QCocoaIntegration::instance()->drag();
     nativeDrag->setAcceptedAction(qt_mac_mapNSDragOperation(operation));
 
-    // keep our state, and QGuiApplication state (buttons member) in-sync,
-    // or future mouse events will be processed incorrectly
-    NSUInteger pmb = [NSEvent pressedMouseButtons];
-    for (int buttonNumber = 0; buttonNumber < 32; buttonNumber++) { // see cocoaButton2QtButton() for the 32 value
-        if (!(pmb & (1 << buttonNumber)))
-            m_buttons &= ~cocoaButton2QtButton(buttonNumber);
-    }
-
-    NSPoint windowPoint = [self.window convertRectFromScreen:NSMakeRect(screenPoint.x, screenPoint.y, 1, 1)].origin;
-    NSPoint nsViewPoint = [self convertPoint: windowPoint fromView: nil]; // NSView/QWindow coordinates
-    QPoint qtWindowPoint(nsViewPoint.x, nsViewPoint.y);
-    QPoint qtScreenPoint = QCocoaScreen::mapFromNative(screenPoint).toPoint();
-
-    QWindowSystemInterface::handleMouseEvent(target, mapWindowCoordinates(m_platformWindow->window(), target, qtWindowPoint), qtScreenPoint, m_buttons);
+    m_buttons = currentlyPressedMouseButtons();
 }
 
 @end
diff --git a/src/plugins/platforms/cocoa/qnsview_mouse.mm b/src/plugins/platforms/cocoa/qnsview_mouse.mm
index a101b5ab6f..34ac1126ad 100644
--- a/src/plugins/platforms/cocoa/qnsview_mouse.mm
+++ b/src/plugins/platforms/cocoa/qnsview_mouse.mm
@@ -201,9 +201,14 @@
     QCocoaDrag* nativeDrag = QCocoaIntegration::instance()->drag();
     nativeDrag->setLastMouseEvent(theEvent, self);
 
-    Qt::KeyboardModifiers keyboardModifiers = [QNSView convertKeyModifiers:[theEvent modifierFlags]];
-    QWindowSystemInterface::handleMouseEvent(targetView->m_platformWindow->window(), timestamp, qtWindowPoint, qtScreenPoint,
-                                             m_buttons, keyboardModifiers, Qt::MouseEventNotSynthesized);
+    const auto modifiers = [QNSView convertKeyModifiers:theEvent.modifierFlags];
+    const auto buttons = currentlyPressedMouseButtons();
+    const auto button = cocoaButton2QtButton(theEvent);
+    const auto eventType = cocoaEvent2QtMouseEvent(theEvent);
+
+    QWindowSystemInterface::handleMouseEvent(targetView->m_platformWindow->window(),
+                                             timestamp, qtWindowPoint, qtScreenPoint,
+                                             buttons, button, eventType, modifiers);
 }
 
 - (bool)handleMouseDownEvent:(NSEvent *)theEvent withButton:(int)buttonNumber