base/message_loop/message_pump_gtk.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_GTK_H_
   6 #define BASE_MESSAGE_LOOP_MESSAGE_PUMP_GTK_H_
   7
   8 #include "base/message_loop/message_pump_glib.h"
   9
  10 typedef union _GdkEvent GdkEvent;
  11 typedef struct _XDisplay Display;
  12
  13 namespace base {
  14
  15 // The documentation for this class is in message_pump_glib.h
  16 class MessagePumpObserver {
  17  public:
  18   // This method is called before processing a message.
  19   virtual void WillProcessEvent(GdkEvent* event) = 0;
  20
  21   // This method is called after processing a message.
  22   virtual void DidProcessEvent(GdkEvent* event) = 0;
  23
  24  protected:
  25   virtual ~MessagePumpObserver() {}
  26 };
  27
  28 // The documentation for this class is in message_pump_glib.h
  29 //
  30 // The nested loop is exited by either posting a quit, or returning false
  31 // from Dispatch.
  32 class MessagePumpDispatcher {
  33  public:
  34   // Dispatches the event. If true is returned processing continues as
  35   // normal. If false is returned, the nested loop exits immediately.
  36   virtual bool Dispatch(GdkEvent* event) = 0;
  37
  38  protected:
  39   virtual ~MessagePumpDispatcher() {}
  40 };
  41
  42 // This class implements a message-pump for dispatching GTK events.
  43 class BASE_EXPORT MessagePumpGtk : public MessagePumpGlib {
  44  public:
  45   MessagePumpGtk();
  46   virtual ~MessagePumpGtk();
  47
  48   // Dispatch an available GdkEvent. Essentially this allows a subclass to do
  49   // some task before/after calling the default handler (EventDispatcher).
  50   void DispatchEvents(GdkEvent* event);
  51
  52   // Returns default X Display.
  53   static Display* GetDefaultXDisplay();
  54
  55  private:
  56   // Invoked from EventDispatcher. Notifies all observers we're about to
  57   // process an event.
  58   void WillProcessEvent(GdkEvent* event);
  59
  60   // Invoked from EventDispatcher. Notifies all observers we processed an
  61   // event.
  62   void DidProcessEvent(GdkEvent* event);
  63
  64   // Callback prior to gdk dispatching an event.
  65   static void EventDispatcher(GdkEvent* event, void* data);
  66
  67   DISALLOW_COPY_AND_ASSIGN(MessagePumpGtk);
  68 };
  69
  70 typedef MessagePumpGtk MessagePumpForUI;
  71
  72 }  // namespace base
  73
  74 #endif  // BASE_MESSAGE_LOOP_MESSAGE_PUMP_GTK_H_