summaryrefslogtreecommitdiffstats
path: root/layout/base/AccessibleCaretEventHub.h
blob: e2fb4c04a26d974df7bef79f60416c1fb1ee6eaf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef AccessibleCaretEventHub_h
#define AccessibleCaretEventHub_h

#include "mozilla/EventForwards.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/WeakPtr.h"
#include "nsCOMPtr.h"
#include "nsIFrame.h"
#include "nsIReflowObserver.h"
#include "nsIScrollObserver.h"
#include "nsISelectionListener.h"
#include "nsPoint.h"
#include "mozilla/RefPtr.h"
#include "nsWeakReference.h"

class nsDocShell;
class nsIPresShell;
class nsITimer;

namespace mozilla {
class AccessibleCaretManager;
class WidgetKeyboardEvent;
class WidgetMouseEvent;
class WidgetTouchEvent;

// -----------------------------------------------------------------------------
// Each PresShell holds a shared pointer to an AccessibleCaretEventHub; each
// AccessibleCaretEventHub holds a unique pointer to an AccessibleCaretManager.
// Thus, there's one AccessibleCaretManager per PresShell.
//
// AccessibleCaretEventHub implements a state pattern. It receives events from
// PresShell and callbacks by observers and listeners, and then relays them to
// the current concrete state which calls necessary event-handling methods in
// AccessibleCaretManager.
//
// We separate AccessibleCaretEventHub from AccessibleCaretManager to make the
// state transitions in AccessibleCaretEventHub testable. We put (nearly) all
// the operations involving PresShell, Selection, and AccessibleCaret
// manipulation in AccessibleCaretManager so that we can mock methods in
// AccessibleCaretManager in gtest. We test the correctness of the state
// transitions by giving events, callbacks, and the return values by mocked
// methods of AccessibleCaretEventHub. See TestAccessibleCaretEventHub.cpp.
//
// Besides dealing with real events, AccessibleCaretEventHub could also
// synthesize fake long-tap events and inject those events to itself on the
// platform lacks eMouseLongTap. Turn on this preference
// "layout.accessiblecaret.use_long_tap_injector" for the fake long-tap events.
//
// State transition diagram:
// http://hg.mozilla.org/mozilla-central/raw-file/default/layout/base/doc/AccessibleCaretEventHubStates.png
// Source code of the diagram:
// http://hg.mozilla.org/mozilla-central/file/default/layout/base/doc/AccessibleCaretEventHubStates.dot
//
// Please see the wiki page for more information.
// https://wiki.mozilla.org/AccessibleCaret
//
class AccessibleCaretEventHub : public nsIReflowObserver,
                                public nsIScrollObserver,
                                public nsISelectionListener,
                                public nsSupportsWeakReference
{
public:
  explicit AccessibleCaretEventHub(nsIPresShell* aPresShell);
  void Init();
  void Terminate();

  nsEventStatus HandleEvent(WidgetEvent* aEvent);

  // Call this function to notify the blur event happened.
  void NotifyBlur(bool aIsLeavingDocument);

  NS_DECL_ISUPPORTS
  NS_DECL_NSIREFLOWOBSERVER
  NS_DECL_NSISELECTIONLISTENER

  // Override nsIScrollObserver methods.
  virtual void ScrollPositionChanged() override;
  virtual void AsyncPanZoomStarted() override;
  virtual void AsyncPanZoomStopped() override;

  // Base state
  class State;
  State* GetState() const;

protected:
  virtual ~AccessibleCaretEventHub();

#define MOZ_DECL_STATE_CLASS_GETTER(aClassName)                                \
  class aClassName;                                                            \
  static State* aClassName();

#define MOZ_IMPL_STATE_CLASS_GETTER(aClassName)                                \
  AccessibleCaretEventHub::State* AccessibleCaretEventHub::aClassName()        \
  {                                                                            \
    static class aClassName singleton;                                         \
    return &singleton;                                                         \
  }

  // Concrete state getters
  MOZ_DECL_STATE_CLASS_GETTER(NoActionState)
  MOZ_DECL_STATE_CLASS_GETTER(PressCaretState)
  MOZ_DECL_STATE_CLASS_GETTER(DragCaretState)
  MOZ_DECL_STATE_CLASS_GETTER(PressNoCaretState)
  MOZ_DECL_STATE_CLASS_GETTER(ScrollState)
  MOZ_DECL_STATE_CLASS_GETTER(PostScrollState)
  MOZ_DECL_STATE_CLASS_GETTER(LongTapState)

  void SetState(State* aState);

  nsEventStatus HandleMouseEvent(WidgetMouseEvent* aEvent);
  nsEventStatus HandleTouchEvent(WidgetTouchEvent* aEvent);
  nsEventStatus HandleKeyboardEvent(WidgetKeyboardEvent* aEvent);

  virtual nsPoint GetTouchEventPosition(WidgetTouchEvent* aEvent,
                                        int32_t aIdentifier) const;
  virtual nsPoint GetMouseEventPosition(WidgetMouseEvent* aEvent) const;

  bool MoveDistanceIsLarge(const nsPoint& aPoint) const;

  void LaunchLongTapInjector();
  void CancelLongTapInjector();
  static void FireLongTap(nsITimer* aTimer, void* aAccessibleCaretEventHub);

  void LaunchScrollEndInjector();
  void CancelScrollEndInjector();
  static void FireScrollEnd(nsITimer* aTimer, void* aAccessibleCaretEventHub);

  // Member variables
  State* mState = NoActionState();

  // Will be set to nullptr in Terminate().
  nsIPresShell* MOZ_NON_OWNING_REF mPresShell = nullptr;

  UniquePtr<AccessibleCaretManager> mManager;

  WeakPtr<nsDocShell> mDocShell;

  // Use this timer for injecting a long tap event when APZ is disabled. If APZ
  // is enabled, it will send long tap event to us.
  nsCOMPtr<nsITimer> mLongTapInjectorTimer;

  // Use this timer for injecting a simulated scroll end.
  nsCOMPtr<nsITimer> mScrollEndInjectorTimer;

  // Last mouse button down event or touch start event point.
  nsPoint mPressPoint{ NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE };

  // For filter multitouch event
  int32_t mActiveTouchId = kInvalidTouchId;

  // Flag to indicate the class has been initialized.
  bool mInitialized = false;

  // Flag to avoid calling Reflow() callback recursively.
  bool mIsInReflowCallback = false;

  // Simulate long tap if the platform does not support eMouseLongTap events.
  static bool sUseLongTapInjector;

  static const int32_t kScrollEndTimerDelay = 300;
  static const int32_t kMoveStartToleranceInPixel = 5;
  static const int32_t kInvalidTouchId = -1;
  static const int32_t kDefaultTouchId = 0; // For mouse event
};

// -----------------------------------------------------------------------------
// The base class for concrete states. A concrete state should inherit from this
// class, and override the methods to handle the events or callbacks. A concrete
// state is also responsible for transforming itself to the next concrete state.
//
class AccessibleCaretEventHub::State
{
public:
  virtual const char* Name() const { return ""; }

  virtual nsEventStatus OnPress(AccessibleCaretEventHub* aContext,
                                const nsPoint& aPoint, int32_t aTouchId,
                                EventClassID aEventClass)
  {
    return nsEventStatus_eIgnore;
  }

  virtual nsEventStatus OnMove(AccessibleCaretEventHub* aContext,
                               const nsPoint& aPoint)
  {
    return nsEventStatus_eIgnore;
  }

  virtual nsEventStatus OnRelease(AccessibleCaretEventHub* aContext)
  {
    return nsEventStatus_eIgnore;
  }

  virtual nsEventStatus OnLongTap(AccessibleCaretEventHub* aContext,
                                  const nsPoint& aPoint)
  {
    return nsEventStatus_eIgnore;
  }

  virtual void OnScrollStart(AccessibleCaretEventHub* aContext) {}
  virtual void OnScrollEnd(AccessibleCaretEventHub* aContext) {}
  virtual void OnScrollPositionChanged(AccessibleCaretEventHub* aContext) {}
  virtual void OnBlur(AccessibleCaretEventHub* aContext,
                      bool aIsLeavingDocument) {}
  virtual void OnSelectionChanged(AccessibleCaretEventHub* aContext,
                                  nsIDOMDocument* aDoc, nsISelection* aSel,
                                  int16_t aReason) {}
  virtual void OnReflow(AccessibleCaretEventHub* aContext) {}
  virtual void Enter(AccessibleCaretEventHub* aContext) {}
  virtual void Leave(AccessibleCaretEventHub* aContext) {}

  explicit State() = default;
  virtual ~State() = default;
  State(const State&) = delete;
  State& operator=(const State&) = delete;
};

} // namespace mozilla

#endif // AccessibleCaretEventHub_h