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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 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 blink {
     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 ENABLE(ASSERT)
     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 == InCompositingUpdate)
    134             return true;
    135         if (state == InPaintInvalidation)
    136             return true;
    137         return false;
    138     }
    139     if (m_state == InPaintInvalidation) {
    140         if (state == PaintInvalidationClean)
    141             return true;
    142         return false;
    143     }
    144     if (m_state == PaintInvalidationClean) {
    145         if (state == InStyleRecalc)
    146             return true;
    147         if (state == InPreLayout)
    148             return true;
    149         if (state == InCompositingUpdate)
    150             return true;
    151         return false;
    152     }
    153     return false;
    154 }
    155 
    156 bool DocumentLifecycle::canRewindTo(State state) const
    157 {
    158     // This transition is bogus, but we've whitelisted it anyway.
    159     if (s_deprecatedTransitionStack && m_state == s_deprecatedTransitionStack->from() && state == s_deprecatedTransitionStack->to())
    160         return true;
    161     return m_state == StyleClean || m_state == AfterPerformLayout || m_state == LayoutClean || m_state == CompositingClean || m_state == PaintInvalidationClean;
    162 }
    163 
    164 #endif
    165 
    166 void DocumentLifecycle::advanceTo(State state)
    167 {
    168     ASSERT(canAdvanceTo(state));
    169     m_state = state;
    170 }
    171 
    172 void DocumentLifecycle::ensureStateAtMost(State state)
    173 {
    174     ASSERT(state == VisualUpdatePending || state == StyleClean || state == LayoutClean);
    175     if (m_state <= state)
    176         return;
    177     ASSERT(canRewindTo(state));
    178     m_state = state;
    179 }
    180 
    181 }
    182