LCOV - code coverage report
Current view: directory - ipc/chromium/src/base - message_pump_glib.h (source / functions) Found Hit Coverage
Test: app.info Lines: 1 0 0.0 %
Date: 2012-06-02 Functions: 1 0 0.0 %

       1                 : // Copyright (c) 2008 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_PUMP_GLIB_H_
       6                 : #define BASE_MESSAGE_PUMP_GLIB_H_
       7                 : 
       8                 : #include "base/message_pump.h"
       9                 : #include "base/observer_list.h"
      10                 : #include "base/scoped_ptr.h"
      11                 : #include "base/time.h"
      12                 : 
      13                 : typedef union _GdkEvent GdkEvent;
      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 MessagePump needed for TYPE_UI MessageLoops on
      21                 : // OS_LINUX platforms using GLib.
      22                 : class MessagePumpForUI : public MessagePump {
      23                 :  public:
      24                 :   // Observer is notified prior to a GdkEvent event being dispatched. As
      25                 :   // Observers are notified of every change, they have to be FAST!
      26                 :   class Observer {
      27                 :    public:
      28                 :     virtual ~Observer() {}
      29                 : 
      30                 :     // This method is called before processing a message.
      31                 :     virtual void WillProcessEvent(GdkEvent* event) = 0;
      32                 : 
      33                 :     // This method is called after processing a message.
      34                 :     virtual void DidProcessEvent(GdkEvent* event) = 0;
      35                 :   };
      36                 : 
      37                 :   // Dispatcher is used during a nested invocation of Run to dispatch events.
      38                 :   // If Run is invoked with a non-NULL Dispatcher, MessageLoop does not
      39                 :   // dispatch events (or invoke gtk_main_do_event), rather every event is
      40                 :   // passed to Dispatcher's Dispatch method for dispatch. It is up to the
      41                 :   // Dispatcher to dispatch, or not, the event.
      42                 :   //
      43                 :   // The nested loop is exited by either posting a quit, or returning false
      44                 :   // from Dispatch.
      45                 :   class Dispatcher {
      46                 :    public:
      47                 :     virtual ~Dispatcher() {}
      48                 :     // Dispatches the event. If true is returned processing continues as
      49                 :     // normal. If false is returned, the nested loop exits immediately.
      50                 :     virtual bool Dispatch(GdkEvent* event) = 0;
      51                 :   };
      52                 : 
      53                 :   MessagePumpForUI();
      54                 :   virtual ~MessagePumpForUI();
      55                 : 
      56                 :   // Like MessagePump::Run, but GdkEvent objects are routed through dispatcher.
      57                 :   virtual void RunWithDispatcher(Delegate* delegate, Dispatcher* dispatcher);
      58                 : 
      59               0 :   virtual void Run(Delegate* delegate) { RunWithDispatcher(delegate, NULL); }
      60                 :   virtual void Quit();
      61                 :   virtual void ScheduleWork();
      62                 :   virtual void ScheduleDelayedWork(const Time& delayed_work_time);
      63                 : 
      64                 :   // Internal methods used for processing the pump callbacks.  They are
      65                 :   // public for simplicity but should not be used directly.  HandlePrepare
      66                 :   // is called during the prepare step of glib, and returns a timeout that
      67                 :   // will be passed to the poll. HandleCheck is called after the poll
      68                 :   // has completed, and returns whether or not HandleDispatch should be called.
      69                 :   // HandleDispatch is called if HandleCheck returned true.
      70                 :   int HandlePrepare();
      71                 :   bool HandleCheck();
      72                 :   void HandleDispatch();
      73                 : 
      74                 :   // Adds an Observer, which will start receiving notifications immediately.
      75                 :   void AddObserver(Observer* observer);
      76                 : 
      77                 :   // Removes an Observer.  It is safe to call this method while an Observer is
      78                 :   // receiving a notification callback.
      79                 :   void RemoveObserver(Observer* observer);
      80                 : 
      81                 :  private:
      82                 :   // We may make recursive calls to Run, so we save state that needs to be
      83                 :   // separate between them in this structure type.
      84                 :   struct RunState {
      85                 :     Delegate* delegate;
      86                 :     Dispatcher* dispatcher;
      87                 : 
      88                 :     // Used to flag that the current Run() invocation should return ASAP.
      89                 :     bool should_quit;
      90                 : 
      91                 :     // Used to count how many Run() invocations are on the stack.
      92                 :     int run_depth;
      93                 : 
      94                 :     // This keeps the state of whether the pump got signaled that there was new
      95                 :     // work to be done. Since we eat the message on the wake up pipe as soon as
      96                 :     // we get it, we keep that state here to stay consistent.
      97                 :     bool has_work;
      98                 :   };
      99                 : 
     100                 :   // Invoked from EventDispatcher. Notifies all observers we're about to
     101                 :   // process an event.
     102                 :   void WillProcessEvent(GdkEvent* event);
     103                 : 
     104                 :   // Invoked from EventDispatcher. Notifies all observers we processed an
     105                 :   // event.
     106                 :   void DidProcessEvent(GdkEvent* event);
     107                 : 
     108                 :   // Callback prior to gdk dispatching an event.
     109                 :   static void EventDispatcher(GdkEvent* event, void* data);
     110                 : 
     111                 :   RunState* state_;
     112                 : 
     113                 :   // This is a GLib structure that we can add event sources to.  We use the
     114                 :   // default GLib context, which is the one to which all GTK events are
     115                 :   // dispatched.
     116                 :   GMainContext* context_;
     117                 : 
     118                 :   // This is the time when we need to do delayed work.
     119                 :   Time delayed_work_time_;
     120                 : 
     121                 :   // The work source.  It is shared by all calls to Run and destroyed when
     122                 :   // the message pump is destroyed.
     123                 :   GSource* work_source_;
     124                 : 
     125                 :   // We use a wakeup pipe to make sure we'll get out of the glib polling phase
     126                 :   // when another thread has scheduled us to do some work.  There is a glib
     127                 :   // mechanism g_main_context_wakeup, but this won't guarantee that our event's
     128                 :   // Dispatch() will be called.
     129                 :   int wakeup_pipe_read_;
     130                 :   int wakeup_pipe_write_;
     131                 :   // Use a scoped_ptr to avoid needing the definition of GPollFD in the header.
     132                 :   scoped_ptr<GPollFD> wakeup_gpollfd_;
     133                 : 
     134                 :   // List of observers.
     135                 :   ObserverList<Observer> observers_;
     136                 : 
     137                 :   DISALLOW_COPY_AND_ASSIGN(MessagePumpForUI);
     138                 : };
     139                 : 
     140                 : }  // namespace base
     141                 : 
     142                 : #endif  // BASE_MESSAGE_PUMP_GLIB_H_

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