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
37namespace blink {
38
39class DocumentLifecycle {
40    WTF_MAKE_NONCOPYABLE(DocumentLifecycle);
41public:
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        InPaintInvalidation,
62        PaintInvalidationClean,
63
64        // Once the document starts shuting down, we cannot return
65        // to the style/layout/rendering states.
66        Stopping,
67        Stopped,
68        Disposed,
69    };
70
71    class Scope {
72        WTF_MAKE_NONCOPYABLE(Scope);
73    public:
74        Scope(DocumentLifecycle&, State finalState);
75        ~Scope();
76
77        void setFinalState(State finalState) { m_finalState = finalState; }
78
79    private:
80        DocumentLifecycle& m_lifecycle;
81        State m_finalState;
82    };
83
84    class DeprecatedTransition {
85        WTF_MAKE_NONCOPYABLE(DeprecatedTransition);
86    public:
87        DeprecatedTransition(State from, State to);
88        ~DeprecatedTransition();
89
90        State from() const { return m_from; }
91        State to() const { return m_to; }
92
93    private:
94        DeprecatedTransition* m_previous;
95        State m_from;
96        State m_to;
97    };
98
99    class DetachScope {
100        WTF_MAKE_NONCOPYABLE(DetachScope);
101    public:
102        explicit DetachScope(DocumentLifecycle& documentLifecycle)
103            : m_documentLifecycle(documentLifecycle)
104        {
105            m_documentLifecycle.incrementDetachCount();
106        }
107
108        ~DetachScope()
109        {
110            m_documentLifecycle.decrementDetachCount();
111        }
112
113    private:
114        DocumentLifecycle& m_documentLifecycle;
115    };
116
117    DocumentLifecycle();
118    ~DocumentLifecycle();
119
120    bool isActive() const { return m_state > Inactive && m_state < Stopping; }
121    State state() const { return m_state; }
122
123    bool stateAllowsTreeMutations() const;
124    bool stateAllowsRenderTreeMutations() const;
125    bool stateAllowsDetach() const;
126
127    void advanceTo(State);
128    void ensureStateAtMost(State);
129
130    void incrementDetachCount() { m_detachCount++; }
131    void decrementDetachCount()
132    {
133        ASSERT(m_detachCount > 0);
134        m_detachCount--;
135    }
136
137private:
138#if ENABLE(ASSERT)
139    bool canAdvanceTo(State) const;
140    bool canRewindTo(State) const;
141#endif
142
143    State m_state;
144    int m_detachCount;
145};
146
147inline bool DocumentLifecycle::stateAllowsTreeMutations() const
148{
149    // FIXME: We should not allow mutations in InPreLayout or AfterPerformLayout either,
150    // but we need to fix MediaList listeners and plugins first.
151    return m_state != InStyleRecalc
152        && m_state != InPerformLayout
153        && m_state != InCompositingUpdate;
154}
155
156inline bool DocumentLifecycle::stateAllowsRenderTreeMutations() const
157{
158    return m_detachCount || m_state == InStyleRecalc;
159}
160
161inline bool DocumentLifecycle::stateAllowsDetach() const
162{
163    return m_state == VisualUpdatePending
164        || m_state == InStyleRecalc
165        || m_state == StyleClean
166        || m_state == InPreLayout
167        || m_state == LayoutClean
168        || m_state == CompositingClean
169        || m_state == PaintInvalidationClean
170        || m_state == Stopping;
171}
172
173}
174
175#endif
176