Linux: Add multi-threaded message loop support (issue #2512)

tests/cefclient/browser/util_gtk.h

@@ -0,0 +1,41 @@
+// Copyright (c) 2018 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+
+#ifndef CEF_TESTS_CEFCLIENT_BROWSER_UTIL_GTK_H_
+#define CEF_TESTS_CEFCLIENT_BROWSER_UTIL_GTK_H_
+#pragma once
+
+#include "include/base/cef_macros.h"
+#include "include/base/cef_platform_thread.h"
+
+namespace client {
+
+// Scoped helper that manages the global GDK lock by calling gdk_threads_enter()
+// and gdk_threads_leave(). The lock is not reentrant so this helper implements
+// additional checking to avoid deadlocks.
+//
+// When using GTK in multi-threaded mode you must do the following:
+// 1. Call gdk_threads_init() before making any other GTK/GDK/GLib calls.
+// 2. Acquire the global lock before making any GTK/GDK calls, and release the
+//    lock afterwards. This should only be done with callbacks that do not
+//    originate from GTK signals (because those callbacks already hold the
+//    lock).
+//
+// See https://www.geany.org/manual/gtk/gtk-faq/x482.html for more information.
+class ScopedGdkThreadsEnter {
+ public:
+  ScopedGdkThreadsEnter();
+  ~ScopedGdkThreadsEnter();
+
+ private:
+  bool take_lock_;
+
+  static base::PlatformThreadId locked_thread_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedGdkThreadsEnter);
+};
+
+}  // namespace client
+
+#endif  // CEF_TESTS_CEFCLIENT_BROWSER_UTIL_GTK_H_