chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h

   1 // Copyright (c) 2011 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 CHROME_BROWSER_CHROMEOS_XINPUT_HIERARCHY_CHANGED_EVENT_LISTENER_H_
   6 #define CHROME_BROWSER_CHROMEOS_XINPUT_HIERARCHY_CHANGED_EVENT_LISTENER_H_
   7 #pragma once
   8
   9 #if defined(TOOLKIT_USES_GTK)
  10 #include <gdk/gdk.h>
  11 #endif
  12
  13 #include "base/memory/singleton.h"
  14 #include "base/message_loop.h"
  15 #include "base/observer_list.h"
  16 #include "chrome/browser/chromeos/device_hierarchy_observer.h"
  17
  18 typedef union _XEvent XEvent;
  19
  20 namespace chromeos {
  21
  22 // XInputHierarchyChangedEventListener listens for an XI_HierarchyChanged event,
  23 // which is sent to Chrome when X detects a system or USB keyboard (or mouse),
  24 // then tells X to change the current XKB keyboard layout. Start by just calling
  25 // instance() to get it going.
  26 class XInputHierarchyChangedEventListener : public MessageLoopForUI::Observer {
  27  public:
  28   static XInputHierarchyChangedEventListener* GetInstance();
  29
  30   void Stop();
  31
  32   void AddObserver(DeviceHierarchyObserver* observer);
  33   void RemoveObserver(DeviceHierarchyObserver* observer);
  34
  35  private:
  36   // Defines the delete on exit Singleton traits we like.  Best to have this
  37   // and const/dest private as recommended for Singletons.
  38   friend struct DefaultSingletonTraits<XInputHierarchyChangedEventListener>;
  39
  40   XInputHierarchyChangedEventListener();
  41   virtual ~XInputHierarchyChangedEventListener();
  42
  43   void Init();
  44   void StopImpl();
  45
  46 #if defined(TOOLKIT_USES_GTK)
  47   // When GTK events are processed, WillProcessXEvent() is not called
  48   // automatically. It is necessary to call the function manually by adding the
  49   // Gdk event filter.
  50   static GdkFilterReturn GdkEventFilter(GdkXEvent* gxevent,
  51                                         GdkEvent* gevent,
  52                                         gpointer data);
  53
  54   // MessageLoopForUI::Observer overrides.
  55   virtual void WillProcessEvent(GdkEvent* event) OVERRIDE {}
  56   virtual void DidProcessEvent(GdkEvent* event) OVERRIDE {}
  57 #else
  58   // MessageLoopForUI::Observer overrides.
  59   virtual base::EventStatus WillProcessEvent(
  60       const base::NativeEvent& event) OVERRIDE;
  61   virtual void DidProcessEvent(const base::NativeEvent& event) OVERRIDE;
  62 #endif
  63
  64   // Returns true if the event was processed, false otherwise.
  65   virtual bool ProcessedXEvent(XEvent* xevent);
  66
  67   // Notify observers that a device has been added/removed.
  68   void NotifyDeviceHierarchyChanged();
  69
  70   bool stopped_;
  71   int xiopcode_;
  72
  73   ObserverList<DeviceHierarchyObserver> observer_list_;
  74
  75   DISALLOW_COPY_AND_ASSIGN(XInputHierarchyChangedEventListener);
  76 };
  77
  78 }  // namespace chromeos
  79
  80 #endif  // CHROME_BROWSER_CHROMEOS_XINPUT_HIERARCHY_CHANGED_EVENT_LISTENER_H_