[gtk/gtk-3-24: 1/2] Ensure gdk_quartz_drag_source freed on all paths.

[Matthias Clasen <matthiasc src gnome org>]

commit a6c3887736a34b669e7d8176e3e47a8f1f9f1e4a
Author: John Ralls <jralls ceridwen us>
Date:   Sun Apr 25 16:53:15 2021 -0700

    Ensure gdk_quartz_drag_source freed on all paths.
    
    New release function _gdk_quartz_drag_source_context_destroy_gtk_only
    gets called when drag fails to start or is cancelled as well as
    when it successfully completes.

 gdk/quartz/GdkQuartzNSWindow.c | 3 +--
 gdk/quartz/gdkdnd-quartz.c     | 8 ++++++++
 gdk/quartz/gdkquartzdnd.h      | 3 +++
 gtk/gtkdnd-quartz.c            | 9 ++++++---
 4 files changed, 18 insertions(+), 5 deletions(-)
---
diff --git a/gdk/quartz/GdkQuartzNSWindow.c b/gdk/quartz/GdkQuartzNSWindow.c
index 005e747d94..f0e57434f4 100644
--- a/gdk/quartz/GdkQuartzNSWindow.c
+++ b/gdk/quartz/GdkQuartzNSWindow.c
@@ -803,8 +803,7 @@ update_context_from_dragging_info (id <NSDraggingInfo> sender)
 
   gdk_event_free (event);
 
-  g_object_unref (_gdk_quartz_drag_source_context);
-  _gdk_quartz_drag_source_context = NULL;
+  _gdk_quartz_drag_source_context_destroy_gtk_only ();
 }
 
 #ifdef AVAILABLE_MAC_OS_X_VERSION_10_7_AND_LATER
diff --git a/gdk/quartz/gdkdnd-quartz.c b/gdk/quartz/gdkdnd-quartz.c
index a68ee3055e..a16e67187a 100644
--- a/gdk/quartz/gdkdnd-quartz.c
+++ b/gdk/quartz/gdkdnd-quartz.c
@@ -59,6 +59,14 @@ _gdk_quartz_window_drag_begin (GdkWindow *window,
   return _gdk_quartz_drag_source_context;
 }
 
+void
+_gdk_quartz_drag_source_context_destroy_gtk_only ()
+{
+     if (_gdk_quartz_drag_source_context)
+          g_object_unref (_gdk_quartz_drag_source_context);
+     _gdk_quartz_drag_source_context = NULL;
+}
+
 static gboolean
 gdk_quartz_drag_context_drag_motion (GdkDragContext  *context,
                                      GdkWindow       *dest_window,
diff --git a/gdk/quartz/gdkquartzdnd.h b/gdk/quartz/gdkquartzdnd.h
index bdcc93a12d..c14d99630d 100644
--- a/gdk/quartz/gdkquartzdnd.h
+++ b/gdk/quartz/gdkquartzdnd.h
@@ -51,6 +51,9 @@ id        gdk_quartz_drag_context_get_dragging_info_libgtk_only (GdkDragContext
 GDK_AVAILABLE_IN_ALL
 GdkDragContext *gdk_quartz_drag_source_context_libgtk_only (void);
 
+GDK_AVAILABLE_IN_3_24
+void _gdk_quartz_drag_source_context_destroy_gtk_only ();
+
 G_END_DECLS
 
 #endif /* __GDK_QUARTZ_DRAG_CONTEXT_H__ */
diff --git a/gtk/gtkdnd-quartz.c b/gtk/gtkdnd-quartz.c
index 959e90d930..3460de6edd 100644
--- a/gtk/gtkdnd-quartz.c
+++ b/gtk/gtkdnd-quartz.c
@@ -1088,8 +1088,10 @@ gtk_drag_begin_idle (gpointer arg)
   [types release];
 
   if ((nswindow = get_toplevel_nswindow (info->source_widget)) == NULL)
-     return G_SOURCE_REMOVE;
-  
+    {
+      _gdk_quartz_drag_source_context_destroy_gtk_only ();
+      return G_SOURCE_REMOVE;
+    }
   /* Ref the context. It's unreffed when the drag has been aborted */
   g_object_ref (info->context);
 
@@ -1101,6 +1103,7 @@ gtk_drag_begin_idle (gpointer arg)
   if (drag_image == NULL)
     {
       g_object_unref (info->context);
+      _gdk_quartz_drag_source_context_destroy_gtk_only ();
       return G_SOURCE_REMOVE;
     }
 
@@ -1669,7 +1672,7 @@ _gtk_drag_source_handle_event (GtkWidget *widget,
       break;
     default:
       g_assert_not_reached ();
-    }  
+    }
 }
 
 /**