base/message_loop/message_pump_glib.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_MESSAGE_LOOP_MESSAGE_PUMP_GLIB_H_
   6 #define BASE_MESSAGE_LOOP_MESSAGE_PUMP_GLIB_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/message_loop/message_pump.h"
  11 #include "base/observer_list.h"
  12 #include "base/time/time.h"
  13
  14 typedef struct _GMainContext GMainContext;
  15 typedef struct _GPollFD GPollFD;
  16 typedef struct _GSource GSource;
  17
  18 namespace base {
  19
  20 // This class implements a base MessagePump needed for TYPE_UI MessageLoops on
  21 // platforms using GLib.
  22 class BASE_EXPORT MessagePumpGlib : public MessagePump {
  23  public:
  24   MessagePumpGlib();
  25   virtual ~MessagePumpGlib();
  26
  27   // Internal methods used for processing the pump callbacks.  They are
  28   // public for simplicity but should not be used directly.  HandlePrepare
  29   // is called during the prepare step of glib, and returns a timeout that
  30   // will be passed to the poll. HandleCheck is called after the poll
  31   // has completed, and returns whether or not HandleDispatch should be called.
  32   // HandleDispatch is called if HandleCheck returned true.
  33   int HandlePrepare();
  34   bool HandleCheck();
  35   void HandleDispatch();
  36
  37   // Overridden from MessagePump:
  38   virtual void Run(Delegate* delegate) OVERRIDE;
  39   virtual void Quit() OVERRIDE;
  40   virtual void ScheduleWork() OVERRIDE;
  41   virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
  42
  43  private:
  44   bool ShouldQuit() const;
  45
  46   // We may make recursive calls to Run, so we save state that needs to be
  47   // separate between them in this structure type.
  48   struct RunState;
  49
  50   RunState* state_;
  51
  52   // This is a GLib structure that we can add event sources to.  We use the
  53   // default GLib context, which is the one to which all GTK events are
  54   // dispatched.
  55   GMainContext* context_;
  56
  57   // This is the time when we need to do delayed work.
  58   TimeTicks delayed_work_time_;
  59
  60   // The work source.  It is shared by all calls to Run and destroyed when
  61   // the message pump is destroyed.
  62   GSource* work_source_;
  63
  64   // We use a wakeup pipe to make sure we'll get out of the glib polling phase
  65   // when another thread has scheduled us to do some work.  There is a glib
  66   // mechanism g_main_context_wakeup, but this won't guarantee that our event's
  67   // Dispatch() will be called.
  68   int wakeup_pipe_read_;
  69   int wakeup_pipe_write_;
  70   // Use a scoped_ptr to avoid needing the definition of GPollFD in the header.
  71   scoped_ptr<GPollFD> wakeup_gpollfd_;
  72
  73   DISALLOW_COPY_AND_ASSIGN(MessagePumpGlib);
  74 };
  75
  76 }  // namespace base
  77
  78 #endif  // BASE_MESSAGE_LOOP_MESSAGE_PUMP_GLIB_H_