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:
Observer(MouseWatcher * mouse_watcher)28 explicit Observer(MouseWatcher* mouse_watcher)
29 : mouse_watcher_(mouse_watcher),
30 notify_listener_factory_(this) {
31 aura::Env::GetInstance()->AddPreTargetHandler(this);
32 }
33
~Observer()34 virtual ~Observer() {
35 aura::Env::GetInstance()->RemovePreTargetHandler(this);
36 }
37
38 // ui::EventHandler implementation:
OnMouseEvent(ui::MouseEvent * event)39 virtual 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:
host() const54 MouseWatcherHost* host() const { return mouse_watcher_->host_.get(); }
55
56 // Called when a mouse event we're interested is seen.
HandleMouseEvent(MouseWatcherHost::MouseEventType event_type)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
NotifyListener()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
~MouseWatcherListener()94 MouseWatcherListener::~MouseWatcherListener() {
95 }
96
~MouseWatcherHost()97 MouseWatcherHost::~MouseWatcherHost() {
98 }
99
MouseWatcher(MouseWatcherHost * host,MouseWatcherListener * listener)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
~MouseWatcher()108 MouseWatcher::~MouseWatcher() {
109 }
110
Start()111 void MouseWatcher::Start() {
112 if (!is_observing())
113 observer_.reset(new Observer(this));
114 }
115
Stop()116 void MouseWatcher::Stop() {
117 observer_.reset(NULL);
118 }
119
NotifyListener()120 void MouseWatcher::NotifyListener() {
121 observer_.reset(NULL);
122 listener_->MouseMovedOutOfHost();
123 }
124
125 } // namespace views
126