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 "core/dom/DocumentLifecycle.h" 33 34 #include "wtf/Assertions.h" 35 36 namespace WebCore { 37 38 static DocumentLifecycle::DeprecatedTransition* s_deprecatedTransitionStack = 0; 39 40 DocumentLifecycle::Scope::Scope(DocumentLifecycle& lifecycle, State finalState) 41 : m_lifecycle(lifecycle) 42 , m_finalState(finalState) 43 { 44 } 45 46 DocumentLifecycle::Scope::~Scope() 47 { 48 m_lifecycle.advanceTo(m_finalState); 49 } 50 51 DocumentLifecycle::DeprecatedTransition::DeprecatedTransition(State from, State to) 52 : m_previous(s_deprecatedTransitionStack) 53 , m_from(from) 54 , m_to(to) 55 { 56 s_deprecatedTransitionStack = this; 57 } 58 59 DocumentLifecycle::DeprecatedTransition::~DeprecatedTransition() 60 { 61 s_deprecatedTransitionStack = m_previous; 62 } 63 64 DocumentLifecycle::DocumentLifecycle() 65 : m_state(Uninitialized) 66 , m_detachCount(0) 67 { 68 } 69 70 DocumentLifecycle::~DocumentLifecycle() 71 { 72 } 73 74 #if ASSERT_ENABLED 75 76 bool DocumentLifecycle::canAdvanceTo(State state) const 77 { 78 if (state > m_state) 79 return true; 80 if (m_state == Disposed) { 81 // FIXME: We can dispose a document multiple times. This seems wrong. 82 // See https://code.google.com/p/chromium/issues/detail?id=301668. 83 return state == Disposed; 84 } 85 if (m_state == StyleClean) { 86 // We can synchronously recalc style. 87 if (state == InStyleRecalc) 88 return true; 89 // We can synchronously perform layout. 90 if (state == InPreLayout) 91 return true; 92 if (state == InPerformLayout) 93 return true; 94 // We can redundant arrive in the style clean state. 95 if (state == StyleClean) 96 return true; 97 return false; 98 } 99 if (m_state == InPreLayout) { 100 if (state == InStyleRecalc) 101 return true; 102 if (state == StyleClean) 103 return true; 104 if (state == InPreLayout) 105 return true; 106 return false; 107 } 108 if (m_state == AfterPerformLayout) { 109 // We can synchronously recompute layout in AfterPerformLayout. 110 // FIXME: Ideally, we would unnest this recursion into a loop. 111 return state == InPreLayout; 112 } 113 if (m_state == LayoutClean) { 114 // We can synchronously recalc style. 115 if (state == InStyleRecalc) 116 return true; 117 // We can synchronously perform layout. 118 if (state == InPreLayout) 119 return true; 120 if (state == InPerformLayout) 121 return true; 122 // We can redundant arrive in the layout clean state. This situation 123 // can happen when we call layout recursively and we unwind the stack. 124 if (state == LayoutClean) 125 return true; 126 if (state == StyleClean) 127 return true; 128 return false; 129 } 130 if (m_state == CompositingClean) { 131 if (state == InStyleRecalc) 132 return true; 133 if (state == InPreLayout) 134 return true; 135 if (state == InCompositingUpdate) 136 return true; 137 return false; 138 } 139 return false; 140 } 141 142 bool DocumentLifecycle::canRewindTo(State state) const 143 { 144 // This transition is bogus, but we've whitelisted it anyway. 145 if (s_deprecatedTransitionStack && m_state == s_deprecatedTransitionStack->from() && state == s_deprecatedTransitionStack->to()) 146 return true; 147 return m_state == StyleClean || m_state == AfterPerformLayout || m_state == LayoutClean || m_state == CompositingClean; 148 } 149 150 #endif 151 152 void DocumentLifecycle::advanceTo(State state) 153 { 154 ASSERT(canAdvanceTo(state)); 155 m_state = state; 156 } 157 158 void DocumentLifecycle::ensureStateAtMost(State state) 159 { 160 ASSERT(state == VisualUpdatePending || state == StyleClean || state == LayoutClean); 161 if (m_state <= state) 162 return; 163 ASSERT(canRewindTo(state)); 164 m_state = state; 165 } 166 167 } 168