diff options
Diffstat (limited to 'base/message_pump_glib.h')
-rw-r--r-- | base/message_pump_glib.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/base/message_pump_glib.h b/base/message_pump_glib.h new file mode 100644 index 0000000..48afb55 --- /dev/null +++ b/base/message_pump_glib.h @@ -0,0 +1,110 @@ +// 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_ |