From ce4cdce4b8b333193d342a977be5edff5587ba5a Mon Sep 17 00:00:00 2001
From: Andrew Comminos <acomminos@mozilla.com>
Date: Mon, 13 Jul 2015 08:58:00 -0400
Subject: [PATCH] Bug 1178799 - Filter X11 SelectionRequest events with an
 invalid requestor on GTK3. r=karlt

--HG--
extra : rebase_source : cd7370af74195ad1c7736c8148d537e3a47bd4d1
---
 widget/gtk/compat/gdk/gdkx.h |  8 ++++++++
 widget/gtk/mozgtk/mozgtk.c   |  1 +
 widget/gtk/nsClipboard.cpp   | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+)

diff --git a/widget/gtk/compat/gdk/gdkx.h b/widget/gtk/compat/gdk/gdkx.h
index dc9d296360a8..5d59720d2f91 100644
--- a/widget/gtk/compat/gdk/gdkx.h
+++ b/widget/gtk/compat/gdk/gdkx.h
@@ -5,12 +5,20 @@
 #ifndef GDKX_WRAPPER_H
 #define GDKX_WRAPPER_H
 
+#define gdk_x11_window_foreign_new_for_display gdk_x11_window_foreign_new_for_display_
 #define gdk_x11_window_lookup_for_display gdk_x11_window_lookup_for_display_
 #define gdk_x11_window_get_xid gdk_x11_window_get_xid_
 #include_next <gdk/gdkx.h>
+#undef gdk_x11_window_foreign_new_for_display
 #undef gdk_x11_window_lookup_for_display
 #undef gdk_x11_window_get_xid
 
+static inline GdkWindow *
+gdk_x11_window_foreign_new_for_display(GdkDisplay *display, Window window)
+{
+  return gdk_window_foreign_new_for_display(display, window);
+}
+
 static inline GdkWindow *
 gdk_x11_window_lookup_for_display(GdkDisplay *display, Window window)
 {
diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
index e42458b49981..697de376cec9 100644
--- a/widget/gtk/mozgtk/mozgtk.c
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -123,6 +123,7 @@ STUB(gdk_x11_get_xatom_by_name)
 STUB(gdk_x11_lookup_xdisplay)
 STUB(gdk_x11_screen_get_xscreen)
 STUB(gdk_x11_visual_get_xvisual)
+STUB(gdk_x11_window_foreign_new_for_display)
 STUB(gdk_x11_window_lookup_for_display)
 STUB(gdk_x11_window_set_user_time)
 STUB(gdk_x11_xatom_to_atom)
diff --git a/widget/gtk/nsClipboard.cpp b/widget/gtk/nsClipboard.cpp
index a78ae435865f..dc2f402dba63 100644
--- a/widget/gtk/nsClipboard.cpp
+++ b/widget/gtk/nsClipboard.cpp
@@ -72,6 +72,11 @@ wait_for_contents          (GtkClipboard *clipboard, GdkAtom target);
 static gchar *
 wait_for_text              (GtkClipboard *clipboard);
 
+static GdkFilterReturn
+selection_request_filter   (GdkXEvent *gdk_xevent,
+                            GdkEvent *event,
+                            gpointer data);
+
 nsClipboard::nsClipboard()
 {
 }
@@ -99,6 +104,13 @@ nsClipboard::Init(void)
 
     os->AddObserver(this, "quit-application", false);
 
+    // A custom event filter to workaround attempting to dereference a null
+    // selection requestor in GTK3 versions before 3.11.3. See bug 1178799.
+#if (MOZ_WIDGET_GTK == 3) && defined(MOZ_X11)
+    if (gtk_check_version(3, 11, 3))
+        gdk_window_add_filter(nullptr, selection_request_filter, nullptr);
+#endif
+
     return NS_OK;
 }
 
@@ -108,6 +120,7 @@ nsClipboard::Observe(nsISupports *aSubject, const char *aTopic, const char16_t *
     if (strcmp(aTopic, "quit-application") == 0) {
         // application is going to quit, save clipboard content
         Store();
+        gdk_window_remove_filter(nullptr, selection_request_filter, nullptr);
     }
     return NS_OK;
 }
@@ -1013,3 +1026,26 @@ wait_for_text(GtkClipboard *clipboard)
     gtk_clipboard_request_text(clipboard, clipboard_text_received, context.get());
     return static_cast<gchar*>(context->Wait());
 }
+
+static GdkFilterReturn
+selection_request_filter(GdkXEvent *gdk_xevent, GdkEvent *event, gpointer data)
+{
+    XEvent *xevent = static_cast<XEvent*>(gdk_xevent);
+    if (xevent->xany.type == SelectionRequest) {
+        if (xevent->xselectionrequest.requestor == None)
+            return GDK_FILTER_REMOVE;
+
+        GdkDisplay *display = gdk_x11_lookup_xdisplay(
+                xevent->xselectionrequest.display);
+        if (!display)
+            return GDK_FILTER_REMOVE;
+
+        GdkWindow *window = gdk_x11_window_foreign_new_for_display(display,
+                xevent->xselectionrequest.requestor);
+        if (!window)
+            return GDK_FILTER_REMOVE;
+
+        g_object_unref(window);
+    }
+    return GDK_FILTER_CONTINUE;
+}