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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 #include "ui/views/mouse_watcher.h" | |
6 | |
7 #include "base/bind.h" | |
8 #include "base/compiler_specific.h" | |
9 #include "base/event_types.h" | |
10 #include "base/memory/weak_ptr.h" | |
11 #include "base/message_loop/message_loop.h" | |
12 #include "ui/aura/env.h" | |
13 #include "ui/aura/window.h" | |
14 #include "ui/events/event.h" | |
15 #include "ui/events/event_constants.h" | |
16 #include "ui/events/event_handler.h" | |
17 #include "ui/events/event_utils.h" | |
18 #include "ui/gfx/screen.h" | |
19 | |
20 namespace views { | |
21 | |
22 // Amount of time between when the mouse moves outside the Host's zone and when | |
23 // the listener is notified. | |
24 const int kNotifyListenerTimeMs = 300; | |
25 | |
26 class MouseWatcher::Observer : public ui::EventHandler { | |
27 public: | |
28 explicit Observer(MouseWatcher* mouse_watcher) | |
29 : mouse_watcher_(mouse_watcher), | |
30 notify_listener_factory_(this) { | |
31 aura::Env::GetInstance()->AddPreTargetHandler(this); | |
32 } | |
33 | |
34 ~Observer() override { | |
35 aura::Env::GetInstance()->RemovePreTargetHandler(this); | |
36 } | |
37 | |
38 // ui::EventHandler implementation: | |
39 void OnMouseEvent(ui::MouseEvent* event) override { | |
40 switch (event->type()) { | |
41 case ui::ET_MOUSE_MOVED: | |
42 case ui::ET_MOUSE_DRAGGED: | |
43 HandleMouseEvent(MouseWatcherHost::MOUSE_MOVE); | |
44 break; | |
45 case ui::ET_MOUSE_EXITED: | |
46 HandleMouseEvent(MouseWatcherHost::MOUSE_EXIT); | |
47 break; | |
48 default: | |
49 break; | |
50 } | |
51 } | |
52 | |
53 private: | |
54 MouseWatcherHost* host() const { return mouse_watcher_->host_.get(); } | |
55 | |
56 // Called when a mouse event we're interested is seen. | |
57 void HandleMouseEvent(MouseWatcherHost::MouseEventType event_type) { | |
58 // It's safe to use last_mouse_location() here as this function is invoked | |
59 // during event dispatching. | |
60 if (!host()->Contains(aura::Env::GetInstance()->last_mouse_location(), | |
61 event_type)) { | |
62 // Mouse moved outside the host's zone, start a timer to notify the | |
63 // listener. | |
64 if (!notify_listener_factory_.HasWeakPtrs()) { | |
65 base::MessageLoop::current()->PostDelayedTask( | |
66 FROM_HERE, | |
67 base::Bind(&Observer::NotifyListener, | |
68 notify_listener_factory_.GetWeakPtr()), | |
69 event_type == MouseWatcherHost::MOUSE_MOVE | |
70 ? base::TimeDelta::FromMilliseconds(kNotifyListenerTimeMs) | |
71 : mouse_watcher_->notify_on_exit_time_); | |
72 } | |
73 } else { | |
74 // Mouse moved quickly out of the host and then into it again, so cancel | |
75 // the timer. | |
76 notify_listener_factory_.InvalidateWeakPtrs(); | |
77 } | |
78 } | |
79 | |
80 void NotifyListener() { | |
81 mouse_watcher_->NotifyListener(); | |
82 // WARNING: we've been deleted. | |
83 } | |
84 | |
85 private: | |
86 MouseWatcher* mouse_watcher_; | |
87 | |
88 // A factory that is used to construct a delayed callback to the listener. | |
89 base::WeakPtrFactory<Observer> notify_listener_factory_; | |
90 | |
91 DISALLOW_COPY_AND_ASSIGN(Observer); | |
92 }; | |
93 | |
94 MouseWatcherListener::~MouseWatcherListener() { | |
95 } | |
96 | |
97 MouseWatcherHost::~MouseWatcherHost() { | |
98 } | |
99 | |
100 MouseWatcher::MouseWatcher(MouseWatcherHost* host, | |
101 MouseWatcherListener* listener) | |
102 : host_(host), | |
103 listener_(listener), | |
104 notify_on_exit_time_(base::TimeDelta::FromMilliseconds( | |
105 kNotifyListenerTimeMs)) { | |
106 } | |
107 | |
108 MouseWatcher::~MouseWatcher() { | |
109 } | |
110 | |
111 void MouseWatcher::Start() { | |
112 if (!is_observing()) | |
113 observer_.reset(new Observer(this)); | |
114 } | |
115 | |
116 void MouseWatcher::Stop() { | |
117 observer_.reset(NULL); | |
118 } | |
119 | |
120 void MouseWatcher::NotifyListener() { | |
121 observer_.reset(NULL); | |
122 listener_->MouseMovedOutOfHost(); | |
123 } | |
124 | |
125 } // namespace views | |
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