1 /*
2 * Copyright (C) 2013 Google 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 are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include "config.h"
32 #include "modules/device_orientation/DeviceSensorEventDispatcher.h"
33
34 namespace WebCore {
35
DeviceSensorEventDispatcher()36 DeviceSensorEventDispatcher::DeviceSensorEventDispatcher()
37 : m_needsPurge(false)
38 , m_isDispatching(false)
39 {
40 }
41
~DeviceSensorEventDispatcher()42 DeviceSensorEventDispatcher::~DeviceSensorEventDispatcher()
43 {
44 }
45
addController(DeviceSensorEventController * controller)46 void DeviceSensorEventDispatcher::addController(DeviceSensorEventController* controller)
47 {
48 bool wasEmpty = m_controllers.isEmpty();
49 if (!m_controllers.contains(controller))
50 m_controllers.append(controller);
51 if (wasEmpty)
52 startListening();
53 }
54
removeController(DeviceSensorEventController * controller)55 void DeviceSensorEventDispatcher::removeController(DeviceSensorEventController* controller)
56 {
57 // Do not actually remove the controller from the vector, instead zero them out.
58 // The zeros are removed in these two cases:
59 // 1. either immediately if we are not dispatching any events,
60 // 2. or after didChangeDeviceMotion/Orientation has dispatched all events.
61 // This is to correctly handle the re-entrancy case when a controller is destroyed
62 // while in the didChangeDeviceMotion/Orientation method.
63 size_t index = m_controllers.find(controller);
64 if (index == kNotFound)
65 return;
66
67 m_controllers[index] = 0;
68 m_needsPurge = true;
69
70 if (!m_isDispatching)
71 purgeControllers();
72 }
73
purgeControllers()74 void DeviceSensorEventDispatcher::purgeControllers()
75 {
76 ASSERT(m_needsPurge);
77
78 size_t i = 0;
79 while (i < m_controllers.size()) {
80 if (!m_controllers[i]) {
81 m_controllers[i] = m_controllers.last();
82 m_controllers.removeLast();
83 } else {
84 ++i;
85 }
86 }
87
88 m_needsPurge = false;
89
90 if (m_controllers.isEmpty())
91 stopListening();
92 }
93
94 } // namespace WebCore
95