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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_
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