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// Copyright (c) 2008 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 <glib.h>
#include "base/message_pump.h"
#include "base/time.h"
namespace base {
// This class implements a MessagePump needed for TYPE_UI MessageLoops on
// OS_LINUX platforms using GLib.
class MessagePumpForUI : public MessagePump {
public:
MessagePumpForUI();
~MessagePumpForUI();
virtual void Run(Delegate* delegate);
virtual void Quit();
virtual void ScheduleWork();
virtual void ScheduleDelayedWork(const Time& delayed_work_time);
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 {
// This is the delegate argument passed to Run.
Delegate* delegate;
// This tells us when to exit the event pump.
bool keep_running;
// This tells our work source when to dispatch DoWork and DoDelayedWork.
bool should_do_work;
// This tells our idle source when to dispatch DoIdleWork.
bool should_do_idle_work;
// Unlike the work source, which is shared by all calls to Run, each Run
// call gets its own idle source because we need to destroy it when we have
// no idle work, and we don't want to destroy someone else's source.
GSource* idle_source;
};
struct WorkSource : GSource {
MessagePumpForUI* self;
};
// The source with these callbacks remain in the main loop forever. They
// will dispatch DoWork and DoDelayedWork, and calculate when and how long
// to block when GLib calls poll internally.
static GSourceFuncs WorkSourceFuncs;
static gboolean WorkSourcePrepare(GSource* source, gint* timeout_ms);
static gboolean WorkSourceCheck(GSource* source);
static gboolean WorkSourceDispatch(GSource* source, GSourceFunc unused_func,
gpointer unused_data);
// The source that uses these callbacks is added as an idle source, which
// means GLib will call it when there is no other work to do. We continue
// doing work as long as DoIdleWork or the other work functions return true.
// Once no work remains, we remove the idle source so GLib will block instead
// of firing it. Then we re-add it when we wake up.
static GSourceFuncs IdleSourceFuncs;
static gboolean IdleSourcePrepare(GSource* source, gint* timeout_ms);
static gboolean IdleSourceCheck(GSource* source);
static gboolean IdleSourceDispatch(GSource* source, GSourceFunc unused_func,
gpointer unused_data);
// This adds a GLib source to the main loop.
GSource* AddSource(GSourceFuncs* funcs, gint priority,
GPollFD* optional_poll_fd);
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.
Time delayed_work_time_;
// We use a pipe to schedule work in a thread-safe way that doesn't interfere
// with our state. When ScheduleWork is called, we write into the pipe which
// ensures poll will not sleep, since we use the read end as an event source.
// When we find data pending on the pipe, we clear it out and know we have
// been given new work.
int write_fd_work_scheduled_;
int read_fd_work_scheduled_;
// The work source. It is shared by all calls to Run and destroyed when
// the message pump is destroyed.
GSource* work_source_;
DISALLOW_COPY_AND_ASSIGN(MessagePumpForUI);
};
} // namespace base
#endif // BASE_MESSAGE_PUMP_GLIB_H_
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