Bug 1767460 [Linux] Implement RAII class for nsDragService::mEventLoopDepth r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D154584

widget/gtk/nsDragService.cpp

@@ -2246,10 +2246,7 @@ gboolean nsDragService::Schedule(DragTask aTask, nsWindow* aWindow,
 
 gboolean nsDragService::TaskDispatchCallback(gpointer data) {
   RefPtr<nsDragService> dragService = static_cast<nsDragService*>(data);
-
-  dragService->EventLoopEnter();
-  auto autoLeave = MakeScopeExit([&] { dragService->EventLoopLeave(); });
-
+  AutoEventLoop loop(dragService);
   return dragService->RunScheduledTask();
 }
 

widget/gtk/nsDragService.h

@@ -99,9 +99,17 @@ class nsDragService final : public nsBaseDragService, public nsIObserver {
   // set the drag icon during drag-begin
   void SetDragIcon(GdkDragContext* aContext);
 
-  void EventLoopEnter() { mEventLoopDepth++; };
-  void EventLoopLeave() { mEventLoopDepth--; };
-  int GetLoopDepth() { return mEventLoopDepth; };
+  class AutoEventLoop {
+    RefPtr<nsDragService> mService;
+
+   public:
+    explicit AutoEventLoop(RefPtr<nsDragService> aService)
+        : mService(std::move(aService)) {
+      mService->mEventLoopDepth++;
+    }
+    ~AutoEventLoop() { mService->mEventLoopDepth--; }
+  };
+  int GetLoopDepth() const { return mEventLoopDepth; };
 
  protected:
   virtual ~nsDragService();

widget/gtk/nsWindow.cpp

@@ -5119,8 +5119,7 @@ void nsWindow::OnDragDataReceivedEvent(GtkWidget* aWidget,
   LOGDRAG("nsWindow::OnDragDataReceived(%p)\n", (void*)this);
 
   RefPtr<nsDragService> dragService = nsDragService::GetInstance();
-  dragService->EventLoopEnter();
-  auto autoLeave = MakeScopeExit([&] { dragService->EventLoopLeave(); });
+  nsDragService::AutoEventLoop loop(dragService);
   dragService->TargetDataReceived(aWidget, aDragContext, aX, aY, aSelectionData,
                                   aInfo, aTime);
 }
@@ -8186,8 +8185,7 @@ gboolean WindowDragMotionHandler(GtkWidget* aWidget,
           innerMostWindow.get(), retx, rety);
 
   RefPtr<nsDragService> dragService = nsDragService::GetInstance();
-  dragService->EventLoopEnter();
-  auto autoLeave = MakeScopeExit([&] { dragService->EventLoopLeave(); });
+  nsDragService::AutoEventLoop loop(dragService);
   if (!dragService->ScheduleMotionEvent(innerMostWindow, aDragContext, point,
                                         aTime)) {
     return FALSE;
@@ -8211,8 +8209,7 @@ void WindowDragLeaveHandler(GtkWidget* aWidget) {
   }
 
   RefPtr<nsDragService> dragService = nsDragService::GetInstance();
-  dragService->EventLoopEnter();
-  auto autoLeave = MakeScopeExit([&] { dragService->EventLoopLeave(); });
+  nsDragService::AutoEventLoop loop(dragService);
 
   nsWindow* mostRecentDragWindow = dragService->GetMostRecentDestWindow();
   if (!mostRecentDragWindow) {
@@ -8273,8 +8270,7 @@ gboolean WindowDragDropHandler(GtkWidget* aWidget, GdkDragContext* aDragContext,
           innerMostWindow.get(), retx, rety);
 
   RefPtr<nsDragService> dragService = nsDragService::GetInstance();
-  dragService->EventLoopEnter();
-  auto autoLeave = MakeScopeExit([&] { dragService->EventLoopLeave(); });
+  nsDragService::AutoEventLoop loop(dragService);
   return dragService->ScheduleDropEvent(innerMostWindow, aDragContext, point,
                                         aTime);
 }