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+// Copyright (c) 2012 The Chromium 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 BASE_MESSAGE_PUMP_GLIB_H_
+#define BASE_MESSAGE_PUMP_GLIB_H_
+
+#include "base/base_export.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_pump.h"
+#include "base/observer_list.h"
+#include "base/time.h"
+
+typedef struct _GMainContext GMainContext;
+typedef struct _GPollFD GPollFD;
+typedef struct _GSource GSource;
+
+namespace base {
+
+// MessagePumpObserver is notified prior to an event being dispatched. As
+// Observers are notified of every change, they have to be FAST! The platform
+// specific implementation of the class is in message_pump_gtk/message_pump_x.
+class MessagePumpObserver;
+
+// MessagePumpDispatcher is used during a nested invocation of Run to dispatch
+// events. If Run is invoked with a non-NULL MessagePumpDispatcher, MessageLoop
+// does not dispatch events (or invoke gtk_main_do_event), rather every event is
+// passed to Dispatcher's Dispatch method for dispatch. It is up to the
+// Dispatcher to dispatch, or not, the event. The platform specific
+// implementation of the class is in message_pump_gtk/message_pump_x.
+class MessagePumpDispatcher;
+
+// This class implements a base MessagePump needed for TYPE_UI MessageLoops on
+// platforms using GLib.
+class BASE_EXPORT MessagePumpGlib : public MessagePump {
+ public:
+ MessagePumpGlib();
+
+ // Like MessagePump::Run, but events are routed through dispatcher.
+ virtual void RunWithDispatcher(Delegate* delegate,
+ MessagePumpDispatcher* dispatcher);
+
+ // Internal methods used for processing the pump callbacks. They are
+ // public for simplicity but should not be used directly. HandlePrepare
+ // is called during the prepare step of glib, and returns a timeout that
+ // will be passed to the poll. HandleCheck is called after the poll
+ // has completed, and returns whether or not HandleDispatch should be called.
+ // HandleDispatch is called if HandleCheck returned true.
+ int HandlePrepare();
+ bool HandleCheck();
+ void HandleDispatch();
+
+ // Adds an Observer, which will start receiving notifications immediately.
+ void AddObserver(MessagePumpObserver* observer);
+
+ // Removes an Observer. It is safe to call this method while an Observer is
+ // receiving a notification callback.
+ void RemoveObserver(MessagePumpObserver* observer);
+
+ // Overridden from MessagePump:
+ virtual void Run(Delegate* delegate) OVERRIDE;
+ virtual void Quit() OVERRIDE;
+ virtual void ScheduleWork() OVERRIDE;
+ virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
+
+ protected:
+ virtual ~MessagePumpGlib();
+
+ // Returns the dispatcher for the current run state (|state_->dispatcher|).
+ MessagePumpDispatcher* GetDispatcher();
+
+ ObserverList<MessagePumpObserver>& observers() { return observers_; }
+
+ private:
+ // We may make recursive calls to Run, so we save state that needs to be
+ // separate between them in this structure type.
+ struct RunState;
+
+ RunState* state_;
+
+ // This is a GLib structure that we can add event sources to. We use the
+ // default GLib context, which is the one to which all GTK events are
+ // dispatched.
+ GMainContext* context_;
+
+ // This is the time when we need to do delayed work.
+ TimeTicks delayed_work_time_;
+
+ // The work source. It is shared by all calls to Run and destroyed when
+ // the message pump is destroyed.
+ GSource* work_source_;
+
+ // We use a wakeup pipe to make sure we'll get out of the glib polling phase
+ // when another thread has scheduled us to do some work. There is a glib
+ // mechanism g_main_context_wakeup, but this won't guarantee that our event's
+ // Dispatch() will be called.
+ int wakeup_pipe_read_;
+ int wakeup_pipe_write_;
+ // Use a scoped_ptr to avoid needing the definition of GPollFD in the header.
+ scoped_ptr<GPollFD> wakeup_gpollfd_;
+
+ // List of observers.
+ ObserverList<MessagePumpObserver> observers_;
+
+ DISALLOW_COPY_AND_ASSIGN(MessagePumpGlib);
+};
+
+} // namespace base
+
+#endif // BASE_MESSAGE_PUMP_GLIB_H_