[gtk/wip/chergert/gdk-macos-gdkdrag: 4/8] macos: check for GdkMacosBaseView before using as such

[Christian Hergert <chergert src gnome org>]

commit f8cab8440619ea0b10d332571ae98d1ac169bc23
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jun 17 17:18:19 2021 -0700

    macos: check for GdkMacosBaseView before using as such
    
    We can get events for external windows such as those from native
    file chooser dialogs.

 gdk/macos/gdkmacosdisplay-translate.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)
---
diff --git a/gdk/macos/gdkmacosdisplay-translate.c b/gdk/macos/gdkmacosdisplay-translate.c
index 2a825879a5..d64dd79e5b 100644
--- a/gdk/macos/gdkmacosdisplay-translate.c
+++ b/gdk/macos/gdkmacosdisplay-translate.c
@@ -788,6 +788,9 @@ get_surface_from_ns_event (GdkMacosDisplay *self,
       NSRect view_frame;
 
       view = (GdkMacosBaseView *)[nswindow contentView];
+      if (!GDK_IS_MACOS_BASE_VIEW (view))
+        goto find_under_pointer;
+
       surface = GDK_SURFACE ([view gdkSurface]);
 
       point = [nsevent locationInWindow];
@@ -846,6 +849,8 @@ get_surface_from_ns_event (GdkMacosDisplay *self,
         }
     }
 
+find_under_pointer:
+
   if (!surface)
     {
       /* Fallback used when no NSSurface set.  This happens e.g. when
@@ -864,17 +869,24 @@ get_surface_from_ns_event (GdkMacosDisplay *self,
 static GdkMacosSurface *
 find_surface_for_keyboard_event (NSEvent *nsevent)
 {
-  GdkMacosBaseView *view = (GdkMacosBaseView *)[[nsevent window] contentView];
-  GdkSurface *surface = GDK_SURFACE ([view gdkSurface]);
-  GdkDisplay *display = gdk_surface_get_display (surface);
-  GdkSeat *seat = gdk_display_get_default_seat (display);
-  GdkDevice *device = gdk_seat_get_keyboard (seat);
-  GdkDeviceGrabInfo *grab = _gdk_display_get_last_device_grab (display, device);
+  NSView *nsview = [[nsevent window] contentView];
+
+  if (GDK_IS_MACOS_BASE_VIEW (nsview))
+    {
+      GdkMacosBaseView *view = (GdkMacosBaseView *)nsview;
+      GdkSurface *surface = GDK_SURFACE ([view gdkSurface]);
+      GdkDisplay *display = gdk_surface_get_display (surface);
+      GdkSeat *seat = gdk_display_get_default_seat (display);
+      GdkDevice *device = gdk_seat_get_keyboard (seat);
+      GdkDeviceGrabInfo *grab = _gdk_display_get_last_device_grab (display, device);
 
-  if (grab && grab->surface && !grab->owner_events)
-    return GDK_MACOS_SURFACE (grab->surface);
+      if (grab && grab->surface && !grab->owner_events)
+        return GDK_MACOS_SURFACE (grab->surface);
 
-  return GDK_MACOS_SURFACE (surface);
+      return GDK_MACOS_SURFACE (surface);
+    }
+
+  return NULL;
 }
 
 static GdkMacosSurface *
@@ -1090,7 +1102,8 @@ _gdk_macos_display_translate (GdkMacosDisplay *self,
   if (!(surface = find_surface_for_ns_event (self, nsevent, &x, &y)))
     return NULL;
 
-  if (!(window = (GdkMacosWindow *)_gdk_macos_surface_get_native (surface)))
+  if (!(window = (GdkMacosWindow *)_gdk_macos_surface_get_native (surface)) ||
+      !GDK_IS_MACOS_WINDOW (window))
     return NULL;
 
   /* Ignore events and break grabs while the window is being