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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 | |
6 * are met: | |
7 * | |
8 * 1. Redistributions of source code must retain the above copyright | |
9 * notice, this list of conditions and the following disclaimer. | |
10 * 2. Redistributions in binary form must reproduce the above copyright | |
11 * notice, this list of conditions and the following disclaimer | |
12 * in the documentation and/or other materials provided with the | |
13 * distribution. | |
14 * 3. Neither the name of Google Inc. nor the names of its contributors | |
15 * may be used to endorse or promote products derived from this | |
16 * 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 #ifndef CustomElementCallbackDispatcher_h | |
32 #define CustomElementCallbackDispatcher_h | |
33 | |
34 #include "core/dom/custom/CustomElementCallbackQueue.h" | |
35 #include "wtf/Vector.h" | |
36 | |
37 namespace blink { | |
38 | |
39 class CustomElementScheduler; | |
40 | |
41 // FIXME: Rename this CustomElementProcessingStack. It only handles | |
42 // the processing stack. | |
43 class CustomElementCallbackDispatcher { | |
44 WTF_MAKE_NONCOPYABLE(CustomElementCallbackDispatcher); | |
45 public: | |
46 // This is stack allocated in many DOM callbacks. Make it cheap. | |
47 class CallbackDeliveryScope { | |
48 public: | |
49 CallbackDeliveryScope() | |
50 : m_savedElementQueueStart(s_elementQueueStart) | |
51 { | |
52 s_elementQueueStart = s_elementQueueEnd; | |
53 } | |
54 | |
55 ~CallbackDeliveryScope() | |
56 { | |
57 if (s_elementQueueStart != s_elementQueueEnd) | |
58 processElementQueueAndPop(); | |
59 s_elementQueueStart = m_savedElementQueueStart; | |
60 } | |
61 | |
62 private: | |
63 size_t m_savedElementQueueStart; | |
64 }; | |
65 | |
66 static bool inCallbackDeliveryScope() { return s_elementQueueStart; } | |
67 | |
68 protected: | |
69 friend class CustomElementScheduler; | |
70 static CustomElementCallbackDispatcher& instance(); | |
71 void enqueue(CustomElementCallbackQueue*); | |
72 | |
73 private: | |
74 CustomElementCallbackDispatcher() | |
75 { | |
76 // Add a null element as a sentinel. This makes it possible to | |
77 // identify elements queued when there is no | |
78 // CallbackDeliveryScope active. Also, if the processing stack | |
79 // is popped when empty, this sentinel will cause a null deref | |
80 // crash. | |
81 CustomElementCallbackQueue* sentinel = 0; | |
82 for (size_t i = 0; i < kNumSentinels; i++) | |
83 m_flattenedProcessingStack.append(sentinel); | |
84 ASSERT(s_elementQueueEnd == m_flattenedProcessingStack.size()); | |
85 } | |
86 | |
87 // The start of the element queue on the top of the processing | |
88 // stack. An offset into instance().m_flattenedProcessingStack. | |
89 static size_t s_elementQueueStart; | |
90 | |
91 // The end of the element queue on the top of the processing | |
92 // stack. A cache of instance().m_flattenedProcessingStack.size(). | |
93 static size_t s_elementQueueEnd; | |
94 | |
95 static CustomElementCallbackQueue::ElementQueueId currentElementQueue() { re
turn CustomElementCallbackQueue::ElementQueueId(s_elementQueueStart); } | |
96 | |
97 static void processElementQueueAndPop(); | |
98 void processElementQueueAndPop(size_t start, size_t end); | |
99 | |
100 // The processing stack, flattened. Element queues lower in the | |
101 // stack appear toward the head of the vector. The first element | |
102 // is a null sentinel value. | |
103 static const size_t kNumSentinels = 1; | |
104 Vector<CustomElementCallbackQueue*> m_flattenedProcessingStack; | |
105 }; | |
106 | |
107 } | |
108 | |
109 #endif // CustomElementCallbackDispatcher_h | |
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