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 #ifndef DocumentLifecycle_h
32 #define DocumentLifecycle_h
33
34 #include "wtf/Assertions.h"
35 #include "wtf/Noncopyable.h"
36
37 namespace WebCore {
38
39 class DocumentLifecycle {
40 WTF_MAKE_NONCOPYABLE(DocumentLifecycle);
41 public:
42 enum State {
43 Uninitialized,
44 Inactive,
45
46 // When the document is active, it traverses these states.
47
48 VisualUpdatePending,
49
50 InStyleRecalc,
51 StyleClean,
52
53 InPreLayout,
54 InPerformLayout,
55 AfterPerformLayout,
56 LayoutClean,
57
58 InCompositingUpdate,
59 CompositingClean,
60
61 // Once the document starts shuting down, we cannot return
62 // to the style/layout/rendering states.
63 Stopping,
64 Stopped,
65 Disposed,
66 };
67
68 class Scope {
69 WTF_MAKE_NONCOPYABLE(Scope);
70 public:
71 Scope(DocumentLifecycle&, State finalState);
72 ~Scope();
73
setFinalState(State finalState)74 void setFinalState(State finalState) { m_finalState = finalState; }
75
76 private:
77 DocumentLifecycle& m_lifecycle;
78 State m_finalState;
79 };
80
81 class DeprecatedTransition {
82 WTF_MAKE_NONCOPYABLE(DeprecatedTransition);
83 public:
84 DeprecatedTransition(State from, State to);
85 ~DeprecatedTransition();
86
from()87 State from() const { return m_from; }
to()88 State to() const { return m_to; }
89
90 private:
91 DeprecatedTransition* m_previous;
92 State m_from;
93 State m_to;
94 };
95
96 class DetachScope {
97 WTF_MAKE_NONCOPYABLE(DetachScope);
98 public:
DetachScope(DocumentLifecycle & documentLifecycle)99 explicit DetachScope(DocumentLifecycle& documentLifecycle)
100 : m_documentLifecycle(documentLifecycle)
101 {
102 m_documentLifecycle.incrementDetachCount();
103 }
104
~DetachScope()105 ~DetachScope()
106 {
107 m_documentLifecycle.decrementDetachCount();
108 }
109
110 private:
111 DocumentLifecycle& m_documentLifecycle;
112 };
113
114 DocumentLifecycle();
115 ~DocumentLifecycle();
116
isActive()117 bool isActive() const { return m_state > Inactive && m_state < Stopping; }
state()118 State state() const { return m_state; }
119
120 bool stateAllowsTreeMutations() const;
121 bool stateAllowsRenderTreeMutations() const;
122 bool stateAllowsDetach() const;
123
124 void advanceTo(State);
125 void ensureStateAtMost(State);
126
incrementDetachCount()127 void incrementDetachCount() { m_detachCount++; }
decrementDetachCount()128 void decrementDetachCount()
129 {
130 ASSERT(m_detachCount > 0);
131 m_detachCount--;
132 }
133
134 private:
135 #if ASSERT_ENABLED
136 bool canAdvanceTo(State) const;
137 bool canRewindTo(State) const;
138 #endif
139
140 State m_state;
141 int m_detachCount;
142 };
143
stateAllowsTreeMutations()144 inline bool DocumentLifecycle::stateAllowsTreeMutations() const
145 {
146 // FIXME: We should not allow mutations in InPreLayout or AfterPerformLayout either,
147 // but we need to fix MediaList listeners and plugins first.
148 return m_state != InStyleRecalc
149 && m_state != InPerformLayout
150 && m_state != InCompositingUpdate;
151 }
152
stateAllowsRenderTreeMutations()153 inline bool DocumentLifecycle::stateAllowsRenderTreeMutations() const
154 {
155 return m_detachCount || m_state == InStyleRecalc;
156 }
157
stateAllowsDetach()158 inline bool DocumentLifecycle::stateAllowsDetach() const
159 {
160 return m_state == VisualUpdatePending
161 || m_state == InStyleRecalc
162 || m_state == StyleClean
163 || m_state == InPreLayout
164 || m_state == LayoutClean
165 || m_state == CompositingClean
166 || m_state == Stopping;
167 }
168
169 }
170
171 #endif
172