1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/message_pump_glib.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,142 @@
1.4 +// Copyright (c) 2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#ifndef BASE_MESSAGE_PUMP_GLIB_H_
1.9 +#define BASE_MESSAGE_PUMP_GLIB_H_
1.10 +
1.11 +#include "base/message_pump.h"
1.12 +#include "base/observer_list.h"
1.13 +#include "base/scoped_ptr.h"
1.14 +#include "base/time.h"
1.15 +
1.16 +typedef union _GdkEvent GdkEvent;
1.17 +typedef struct _GMainContext GMainContext;
1.18 +typedef struct _GPollFD GPollFD;
1.19 +typedef struct _GSource GSource;
1.20 +
1.21 +namespace base {
1.22 +
1.23 +// This class implements a MessagePump needed for TYPE_UI MessageLoops on
1.24 +// OS_LINUX platforms using GLib.
1.25 +class MessagePumpForUI : public MessagePump {
1.26 + public:
1.27 + // Observer is notified prior to a GdkEvent event being dispatched. As
1.28 + // Observers are notified of every change, they have to be FAST!
1.29 + class Observer {
1.30 + public:
1.31 + virtual ~Observer() {}
1.32 +
1.33 + // This method is called before processing a message.
1.34 + virtual void WillProcessEvent(GdkEvent* event) = 0;
1.35 +
1.36 + // This method is called after processing a message.
1.37 + virtual void DidProcessEvent(GdkEvent* event) = 0;
1.38 + };
1.39 +
1.40 + // Dispatcher is used during a nested invocation of Run to dispatch events.
1.41 + // If Run is invoked with a non-NULL Dispatcher, MessageLoop does not
1.42 + // dispatch events (or invoke gtk_main_do_event), rather every event is
1.43 + // passed to Dispatcher's Dispatch method for dispatch. It is up to the
1.44 + // Dispatcher to dispatch, or not, the event.
1.45 + //
1.46 + // The nested loop is exited by either posting a quit, or returning false
1.47 + // from Dispatch.
1.48 + class Dispatcher {
1.49 + public:
1.50 + virtual ~Dispatcher() {}
1.51 + // Dispatches the event. If true is returned processing continues as
1.52 + // normal. If false is returned, the nested loop exits immediately.
1.53 + virtual bool Dispatch(GdkEvent* event) = 0;
1.54 + };
1.55 +
1.56 + MessagePumpForUI();
1.57 + virtual ~MessagePumpForUI();
1.58 +
1.59 + // Like MessagePump::Run, but GdkEvent objects are routed through dispatcher.
1.60 + virtual void RunWithDispatcher(Delegate* delegate, Dispatcher* dispatcher);
1.61 +
1.62 + virtual void Run(Delegate* delegate) { RunWithDispatcher(delegate, NULL); }
1.63 + virtual void Quit();
1.64 + virtual void ScheduleWork();
1.65 + virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time);
1.66 +
1.67 + // Internal methods used for processing the pump callbacks. They are
1.68 + // public for simplicity but should not be used directly. HandlePrepare
1.69 + // is called during the prepare step of glib, and returns a timeout that
1.70 + // will be passed to the poll. HandleCheck is called after the poll
1.71 + // has completed, and returns whether or not HandleDispatch should be called.
1.72 + // HandleDispatch is called if HandleCheck returned true.
1.73 + int HandlePrepare();
1.74 + bool HandleCheck();
1.75 + void HandleDispatch();
1.76 +
1.77 + // Adds an Observer, which will start receiving notifications immediately.
1.78 + void AddObserver(Observer* observer);
1.79 +
1.80 + // Removes an Observer. It is safe to call this method while an Observer is
1.81 + // receiving a notification callback.
1.82 + void RemoveObserver(Observer* observer);
1.83 +
1.84 + private:
1.85 + // We may make recursive calls to Run, so we save state that needs to be
1.86 + // separate between them in this structure type.
1.87 + struct RunState {
1.88 + Delegate* delegate;
1.89 + Dispatcher* dispatcher;
1.90 +
1.91 + // Used to flag that the current Run() invocation should return ASAP.
1.92 + bool should_quit;
1.93 +
1.94 + // Used to count how many Run() invocations are on the stack.
1.95 + int run_depth;
1.96 +
1.97 + // This keeps the state of whether the pump got signaled that there was new
1.98 + // work to be done. Since we eat the message on the wake up pipe as soon as
1.99 + // we get it, we keep that state here to stay consistent.
1.100 + bool has_work;
1.101 + };
1.102 +
1.103 + // Invoked from EventDispatcher. Notifies all observers we're about to
1.104 + // process an event.
1.105 + void WillProcessEvent(GdkEvent* event);
1.106 +
1.107 + // Invoked from EventDispatcher. Notifies all observers we processed an
1.108 + // event.
1.109 + void DidProcessEvent(GdkEvent* event);
1.110 +
1.111 + // Callback prior to gdk dispatching an event.
1.112 + static void EventDispatcher(GdkEvent* event, void* data);
1.113 +
1.114 + RunState* state_;
1.115 +
1.116 + // This is a GLib structure that we can add event sources to. We use the
1.117 + // default GLib context, which is the one to which all GTK events are
1.118 + // dispatched.
1.119 + GMainContext* context_;
1.120 +
1.121 + // This is the time when we need to do delayed work.
1.122 + TimeTicks delayed_work_time_;
1.123 +
1.124 + // The work source. It is shared by all calls to Run and destroyed when
1.125 + // the message pump is destroyed.
1.126 + GSource* work_source_;
1.127 +
1.128 + // We use a wakeup pipe to make sure we'll get out of the glib polling phase
1.129 + // when another thread has scheduled us to do some work. There is a glib
1.130 + // mechanism g_main_context_wakeup, but this won't guarantee that our event's
1.131 + // Dispatch() will be called.
1.132 + int wakeup_pipe_read_;
1.133 + int wakeup_pipe_write_;
1.134 + // Use a scoped_ptr to avoid needing the definition of GPollFD in the header.
1.135 + scoped_ptr<GPollFD> wakeup_gpollfd_;
1.136 +
1.137 + // List of observers.
1.138 + ObserverList<Observer> observers_;
1.139 +
1.140 + DISALLOW_COPY_AND_ASSIGN(MessagePumpForUI);
1.141 +};
1.142 +
1.143 +} // namespace base
1.144 +
1.145 +#endif // BASE_MESSAGE_PUMP_GLIB_H_
