window_event_dispatcher.h revision 010d83a9304c5a91596085d917d248abff47903a 
1// Copyright 2014 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 UI_AURA_WINDOW_EVENT_DISPATCHER_H_
6#define UI_AURA_WINDOW_EVENT_DISPATCHER_H_
7
8#include <vector>
9
10#include "base/basictypes.h"
11#include "base/gtest_prod_util.h"
12#include "base/memory/ref_counted.h"
13#include "base/memory/scoped_ptr.h"
14#include "base/memory/weak_ptr.h"
15#include "base/message_loop/message_loop.h"
16#include "base/scoped_observer.h"
17#include "ui/aura/aura_export.h"
18#include "ui/aura/client/capture_delegate.h"
19#include "ui/aura/env_observer.h"
20#include "ui/aura/window_observer.h"
21#include "ui/base/cursor/cursor.h"
22#include "ui/events/event_constants.h"
23#include "ui/events/event_processor.h"
24#include "ui/events/event_targeter.h"
25#include "ui/events/gestures/gesture_recognizer.h"
26#include "ui/events/gestures/gesture_types.h"
27#include "ui/gfx/native_widget_types.h"
28#include "ui/gfx/point.h"
29
30namespace gfx {
31class Size;
32class Transform;
33}
34
35namespace ui {
36class GestureEvent;
37class GestureRecognizer;
38class KeyEvent;
39class MouseEvent;
40class ScrollEvent;
41class TouchEvent;
42}
43
44namespace aura {
45class TestScreen;
46class WindowTargeter;
47class WindowTreeHost;
48
49// WindowEventDispatcher orchestrates event dispatch within a window tree
50// owned by WindowTreeHost. WTH also owns the WED.
51// TODO(beng): In progress, remove functionality not directly related to
52//             event dispatch.
53class AURA_EXPORT WindowEventDispatcher : public ui::EventProcessor,
54                                          public ui::GestureEventHelper,
55                                          public client::CaptureDelegate,
56                                          public WindowObserver,
57                                          public EnvObserver {
58 public:
59  explicit WindowEventDispatcher(WindowTreeHost* host);
60  virtual ~WindowEventDispatcher();
61
62  Window* mouse_pressed_handler() { return mouse_pressed_handler_; }
63  Window* mouse_moved_handler() { return mouse_moved_handler_; }
64
65  // Repost event for re-processing. Used when exiting context menus.
66  // We only support the ET_MOUSE_PRESSED and ET_GESTURE_TAP_DOWN event
67  // types (although the latter is currently a no-op).
68  void RepostEvent(const ui::LocatedEvent& event);
69
70  // Invoked when the mouse events get enabled or disabled.
71  void OnMouseEventsEnableStateChanged(bool enabled);
72
73  void DispatchCancelModeEvent();
74
75  // Dispatches a ui::ET_MOUSE_EXITED event at |point|.
76  // TODO(beng): needed only for WTH::OnCursorVisibilityChanged().
77  void DispatchMouseExitAtPoint(const gfx::Point& point);
78
79  // Gesture Recognition -------------------------------------------------------
80
81  // When a touch event is dispatched to a Window, it may want to process the
82  // touch event asynchronously. In such cases, the window should consume the
83  // event during the event dispatch. Once the event is properly processed, the
84  // window should let the WindowEventDispatcher know about the result of the
85  // event processing, so that gesture events can be properly created and
86  // dispatched.
87  void ProcessedTouchEvent(ui::TouchEvent* event,
88                           Window* window,
89                           ui::EventResult result);
90
91  // These methods are used to defer the processing of mouse/touch events
92  // related to resize. A client (typically a RenderWidgetHostViewAura) can call
93  // HoldPointerMoves when an resize is initiated and then ReleasePointerMoves
94  // once the resize is completed.
95  //
96  // More than one hold can be invoked and each hold must be cancelled by a
97  // release before we resume normal operation.
98  void HoldPointerMoves();
99  void ReleasePointerMoves();
100
101  // Gets the last location seen in a mouse event in this root window's
102  // coordinates. This may return a point outside the root window's bounds.
103  gfx::Point GetLastMouseLocationInRoot() const;
104
105  void OnHostLostMouseGrab();
106  void OnCursorMovedToRootLocation(const gfx::Point& root_location);
107
108  // TODO(beng): This is only needed because this cleanup needs to happen after
109  //             all other observers are notified of OnWindowDestroying() but
110  //             before OnWindowDestroyed() is sent (i.e. while the window
111  //             hierarchy is still intact). This didn't seem worth adding a
112  //             generic notification for as only this class needs to implement
113  //             it. I would however like to find a way to do this via an
114  //             observer.
115  void OnPostNotifiedWindowDestroying(Window* window);
116
117 private:
118  FRIEND_TEST_ALL_PREFIXES(WindowEventDispatcherTest,
119                           KeepTranslatedEventInRoot);
120
121  friend class Window;
122  friend class TestScreen;
123
124  // The parameter for OnWindowHidden() to specify why window is hidden.
125  enum WindowHiddenReason {
126    WINDOW_DESTROYED,  // Window is destroyed.
127    WINDOW_HIDDEN,     // Window is hidden.
128    WINDOW_MOVING,     // Window is temporarily marked as hidden due to move
129                       // across root windows.
130  };
131
132  Window* window();
133  const Window* window() const;
134
135  // Updates the event with the appropriate transform for the device scale
136  // factor. The WindowEventDispatcher dispatches events in the physical pixel
137  // coordinate. But the event processing from WindowEventDispatcher onwards
138  // happen in device-independent pixel coordinate. So it is necessary to update
139  // the event received from the host.
140  void TransformEventForDeviceScaleFactor(ui::LocatedEvent* event);
141
142  // Dispatches OnMouseExited to the |window| which is hiding if necessary.
143  void DispatchMouseExitToHidingWindow(Window* window);
144
145  // Dispatches the specified event type (intended for enter/exit) to the
146  // |mouse_moved_handler_|.
147  ui::EventDispatchDetails DispatchMouseEnterOrExit(
148      const ui::MouseEvent& event,
149      ui::EventType type) WARN_UNUSED_RESULT;
150  ui::EventDispatchDetails ProcessGestures(
151      ui::GestureRecognizer::Gestures* gestures) WARN_UNUSED_RESULT;
152
153  // Called when a window becomes invisible, either by being removed
154  // from root window hierarchy, via SetVisible(false) or being destroyed.
155  // |reason| specifies what triggered the hiding. Note that becoming invisible
156  // will cause a window to lose capture and some windows may destroy themselves
157  // on capture (like DragDropTracker).
158  void OnWindowHidden(Window* invisible, WindowHiddenReason reason);
159
160  // Returns a target window for the given gesture event.
161  Window* GetGestureTarget(ui::GestureEvent* event);
162
163  // Overridden from aura::client::CaptureDelegate:
164  virtual void UpdateCapture(Window* old_capture, Window* new_capture) OVERRIDE;
165  virtual void OnOtherRootGotCapture() OVERRIDE;
166  virtual void SetNativeCapture() OVERRIDE;
167  virtual void ReleaseNativeCapture() OVERRIDE;
168
169  // Overridden from ui::EventProcessor:
170  virtual ui::EventTarget* GetRootTarget() OVERRIDE;
171  virtual void PrepareEventForDispatch(ui::Event* event) OVERRIDE;
172
173  // Overridden from ui::EventDispatcherDelegate.
174  virtual bool CanDispatchToTarget(ui::EventTarget* target) OVERRIDE;
175  virtual ui::EventDispatchDetails PreDispatchEvent(ui::EventTarget* target,
176                                                    ui::Event* event) OVERRIDE;
177  virtual ui::EventDispatchDetails PostDispatchEvent(
178      ui::EventTarget* target, const ui::Event& event) OVERRIDE;
179
180  // Overridden from ui::GestureEventHelper.
181  virtual bool CanDispatchToConsumer(ui::GestureConsumer* consumer) OVERRIDE;
182  virtual void DispatchGestureEvent(ui::GestureEvent* event) OVERRIDE;
183  virtual void DispatchCancelTouchEvent(ui::TouchEvent* event) OVERRIDE;
184
185  // Overridden from WindowObserver:
186  virtual void OnWindowDestroying(Window* window) OVERRIDE;
187  virtual void OnWindowDestroyed(Window* window) OVERRIDE;
188  virtual void OnWindowAddedToRootWindow(Window* window) OVERRIDE;
189  virtual void OnWindowRemovingFromRootWindow(Window* window,
190                                              Window* new_root) OVERRIDE;
191  virtual void OnWindowVisibilityChanging(Window* window,
192                                          bool visible) OVERRIDE;
193  virtual void OnWindowVisibilityChanged(Window* window, bool visible) OVERRIDE;
194  virtual void OnWindowBoundsChanged(Window* window,
195                                     const gfx::Rect& old_bounds,
196                                     const gfx::Rect& new_bounds) OVERRIDE;
197  virtual void OnWindowTransforming(Window* window) OVERRIDE;
198  virtual void OnWindowTransformed(Window* window) OVERRIDE;
199
200  // Overridden from EnvObserver:
201  virtual void OnWindowInitialized(Window* window) OVERRIDE;
202
203  // We hold and aggregate mouse drags and touch moves as a way of throttling
204  // resizes when HoldMouseMoves() is called. The following methods are used to
205  // dispatch held and newly incoming mouse and touch events, typically when an
206  // event other than one of these needs dispatching or a matching
207  // ReleaseMouseMoves()/ReleaseTouchMoves() is called.  NOTE: because these
208  // methods dispatch events from WindowTreeHost the coordinates are in terms of
209  // the root.
210  ui::EventDispatchDetails DispatchHeldEvents() WARN_UNUSED_RESULT;
211
212  // Posts a task to send synthesized mouse move event if there is no a pending
213  // task.
214  void PostSynthesizeMouseMove();
215
216  // Creates and dispatches synthesized mouse move event using the current mouse
217  // location.
218  ui::EventDispatchDetails SynthesizeMouseMoveEvent() WARN_UNUSED_RESULT;
219
220  // Calls SynthesizeMouseMove() if |window| is currently visible and contains
221  // the mouse cursor.
222  void SynthesizeMouseMoveAfterChangeToWindow(Window* window);
223
224  void PreDispatchLocatedEvent(Window* target, ui::LocatedEvent* event);
225  void PreDispatchMouseEvent(Window* target, ui::MouseEvent* event);
226  void PreDispatchTouchEvent(Window* target, ui::TouchEvent* event);
227
228  WindowTreeHost* host_;
229
230  // Touch ids that are currently down.
231  uint32 touch_ids_down_;
232
233  Window* mouse_pressed_handler_;
234  Window* mouse_moved_handler_;
235  Window* event_dispatch_target_;
236  Window* old_dispatch_target_;
237
238  bool synthesize_mouse_move_;
239
240  // How many move holds are outstanding. We try to defer dispatching
241  // touch/mouse moves while the count is > 0.
242  int move_hold_count_;
243  // The location of |held_move_event_| is in |window_|'s coordinate.
244  scoped_ptr<ui::LocatedEvent> held_move_event_;
245
246  // Allowing for reposting of events. Used when exiting context menus.
247  scoped_ptr<ui::LocatedEvent> held_repostable_event_;
248
249  // Set when dispatching a held event.
250  bool dispatching_held_event_;
251
252  ScopedObserver<aura::Window, aura::WindowObserver> observer_manager_;
253
254  // Used to schedule reposting an event.
255  base::WeakPtrFactory<WindowEventDispatcher> repost_event_factory_;
256
257  // Used to schedule DispatchHeldEvents() when |move_hold_count_| goes to 0.
258  base::WeakPtrFactory<WindowEventDispatcher> held_event_factory_;
259
260  DISALLOW_COPY_AND_ASSIGN(WindowEventDispatcher);
261};
262
263}  // namespace aura
264
265#endif  // UI_AURA_WINDOW_EVENT_DISPATCHER_H_
266