1/*
2 * Copyright (C) 2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/Vector.h>
29
30namespace WebCore {
31
32class OrientationNotifier {
33public:
34 explicit OrientationNotifier(int orientation) { m_orientation = orientation; }
35 ~OrientationNotifier();
36
37 void orientationChanged(int orientation);
38
39 class Observer {
40 public:
41 virtual ~Observer();
42 virtual void orientationChanged(int orientation) = 0;
43 void setNotifier(OrientationNotifier*);
44
45 private:
46 OrientationNotifier* m_notifier { nullptr };
47 };
48
49 void addObserver(Observer&);
50 void removeObserver(Observer&);
51 int orientation() const { return m_orientation; }
52
53private:
54 Vector<std::reference_wrapper<Observer>> m_observers;
55 int m_orientation;
56};
57
58inline OrientationNotifier::~OrientationNotifier()
59{
60 for (Observer& observer : m_observers)
61 observer.setNotifier(nullptr);
62}
63
64inline OrientationNotifier::Observer::~Observer()
65{
66 if (m_notifier)
67 m_notifier->removeObserver(*this);
68}
69
70inline void OrientationNotifier::Observer::setNotifier(OrientationNotifier* notifier)
71{
72 if (m_notifier == notifier)
73 return;
74
75 if (m_notifier && notifier)
76 m_notifier->removeObserver(*this);
77
78 ASSERT(!m_notifier || !notifier);
79 m_notifier = notifier;
80}
81
82inline void OrientationNotifier::orientationChanged(int orientation)
83{
84 m_orientation = orientation;
85 for (Observer& observer : m_observers)
86 observer.orientationChanged(orientation);
87}
88
89inline void OrientationNotifier::addObserver(Observer& observer)
90{
91 m_observers.append(observer);
92 observer.setNotifier(this);
93}
94
95inline void OrientationNotifier::removeObserver(Observer& observer)
96{
97 m_observers.removeFirstMatching([&observer](auto item) {
98 if (&observer != &item.get())
99 return false;
100 observer.setNotifier(nullptr);
101 return true;
102 });
103}
104
105}
106