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 blink { 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 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 } 136 137 private: 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 }; 146 147 inline 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 } 155 156 inline bool DocumentLifecycle::stateAllowsRenderTreeMutations() const 157 { 158 return m_detachCount || m_state == InStyleRecalc; 159 } 160 161 inline 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