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      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_
     75