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The Tor Browser
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SMILInstanceTime.cpp (5591B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "SMILInstanceTime.h"
      8 
      9 #include "mozilla/AutoRestore.h"
     10 #include "mozilla/SMILInterval.h"
     11 #include "mozilla/SMILTimeValueSpec.h"
     12 
     13 namespace mozilla {
     14 
     15 //----------------------------------------------------------------------
     16 // Implementation
     17 
     18 SMILInstanceTime::SMILInstanceTime(const SMILTimeValue& aTime,
     19                                   SMILInstanceTimeSource aSource,
     20                                   SMILTimeValueSpec* aCreator,
     21                                   SMILInterval* aBaseInterval)
     22    : mTime(aTime),
     23      mFlags(0),
     24      mVisited(false),
     25      mFixedEndpointRefCnt(0),
     26      mSerial(0),
     27      mCreator(aCreator),
     28      mBaseInterval(nullptr)  // This will get set to aBaseInterval in a call to
     29                              // SetBaseInterval() at end of constructor
     30 {
     31  switch (aSource) {
     32    case SOURCE_NONE:
     33      // No special flags
     34      break;
     35 
     36    case SOURCE_DOM:
     37      mFlags = kDynamic | kFromDOM;
     38      break;
     39 
     40    case SOURCE_SYNCBASE:
     41      mFlags = kMayUpdate;
     42      break;
     43 
     44    case SOURCE_EVENT:
     45      mFlags = kDynamic;
     46      break;
     47  }
     48 
     49  SetBaseInterval(aBaseInterval);
     50 }
     51 
     52 SMILInstanceTime::~SMILInstanceTime() {
     53  MOZ_ASSERT(!mBaseInterval,
     54             "Destroying instance time without first calling Unlink()");
     55  MOZ_ASSERT(mFixedEndpointRefCnt == 0,
     56             "Destroying instance time that is still used as the fixed "
     57             "endpoint of an interval");
     58 }
     59 
     60 void SMILInstanceTime::Unlink() {
     61  RefPtr<SMILInstanceTime> deathGrip(this);
     62  if (mBaseInterval) {
     63    mBaseInterval->RemoveDependentTime(*this);
     64    mBaseInterval = nullptr;
     65  }
     66  mCreator = nullptr;
     67 }
     68 
     69 void SMILInstanceTime::HandleChangedInterval(
     70    const SMILTimeContainer* aSrcContainer, bool aBeginObjectChanged,
     71    bool aEndObjectChanged) {
     72  // It's possible a sequence of notifications might cause our base interval to
     73  // be updated and then deleted. Furthermore, the delete might happen whilst
     74  // we're still in the queue to be notified of the change. In any case, if we
     75  // don't have a base interval, just ignore the change.
     76  if (!mBaseInterval) return;
     77 
     78  MOZ_ASSERT(mCreator, "Base interval is set but creator is not.");
     79 
     80  if (mVisited) {
     81    // Break the cycle here
     82    Unlink();
     83    return;
     84  }
     85 
     86  bool objectChanged =
     87      mCreator->DependsOnBegin() ? aBeginObjectChanged : aEndObjectChanged;
     88 
     89  RefPtr<SMILInstanceTime> deathGrip(this);
     90  mozilla::AutoRestore<bool> setVisited(mVisited);
     91  mVisited = true;
     92 
     93  mCreator->HandleChangedInstanceTime(*GetBaseTime(), aSrcContainer, *this,
     94                                      objectChanged);
     95 }
     96 
     97 void SMILInstanceTime::HandleDeletedInterval() {
     98  MOZ_ASSERT(mBaseInterval,
     99             "Got call to HandleDeletedInterval on an independent instance "
    100             "time");
    101  MOZ_ASSERT(mCreator, "Base interval is set but creator is not");
    102 
    103  mBaseInterval = nullptr;
    104  mFlags &= ~kMayUpdate;  // Can't update without a base interval
    105 
    106  RefPtr<SMILInstanceTime> deathGrip(this);
    107  mCreator->HandleDeletedInstanceTime(*this);
    108  mCreator = nullptr;
    109 }
    110 
    111 void SMILInstanceTime::HandleFilteredInterval() {
    112  MOZ_ASSERT(mBaseInterval,
    113             "Got call to HandleFilteredInterval on an independent instance "
    114             "time");
    115 
    116  mBaseInterval = nullptr;
    117  mFlags &= ~kMayUpdate;  // Can't update without a base interval
    118  mCreator = nullptr;
    119 }
    120 
    121 bool SMILInstanceTime::ShouldPreserve() const {
    122  return mFixedEndpointRefCnt > 0 || (mFlags & kWasDynamicEndpoint);
    123 }
    124 
    125 void SMILInstanceTime::UnmarkShouldPreserve() {
    126  mFlags &= ~kWasDynamicEndpoint;
    127 }
    128 
    129 void SMILInstanceTime::AddRefFixedEndpoint() {
    130  MOZ_ASSERT(mFixedEndpointRefCnt < UINT16_MAX,
    131             "Fixed endpoint reference count upper limit reached");
    132  ++mFixedEndpointRefCnt;
    133  mFlags &= ~kMayUpdate;  // Once fixed, always fixed
    134 }
    135 
    136 void SMILInstanceTime::ReleaseFixedEndpoint() {
    137  MOZ_ASSERT(mFixedEndpointRefCnt > 0, "Duplicate release");
    138  --mFixedEndpointRefCnt;
    139  if (mFixedEndpointRefCnt == 0 && IsDynamic()) {
    140    mFlags |= kWasDynamicEndpoint;
    141  }
    142 }
    143 
    144 bool SMILInstanceTime::IsDependentOn(const SMILInstanceTime& aOther) const {
    145  if (mVisited) return false;
    146 
    147  const SMILInstanceTime* myBaseTime = GetBaseTime();
    148  if (!myBaseTime) return false;
    149 
    150  if (myBaseTime == &aOther) return true;
    151 
    152  mozilla::AutoRestore<bool> setVisited(mVisited);
    153  mVisited = true;
    154  return myBaseTime->IsDependentOn(aOther);
    155 }
    156 
    157 const SMILInstanceTime* SMILInstanceTime::GetBaseTime() const {
    158  if (!mBaseInterval) {
    159    return nullptr;
    160  }
    161 
    162  MOZ_ASSERT(mCreator, "Base interval is set but there is no creator.");
    163  if (!mCreator) {
    164    return nullptr;
    165  }
    166 
    167  return mCreator->DependsOnBegin() ? mBaseInterval->Begin()
    168                                    : mBaseInterval->End();
    169 }
    170 
    171 void SMILInstanceTime::SetBaseInterval(SMILInterval* aBaseInterval) {
    172  MOZ_ASSERT(!mBaseInterval,
    173             "Attempting to reassociate an instance time with a different "
    174             "interval.");
    175 
    176  if (aBaseInterval) {
    177    MOZ_ASSERT(mCreator,
    178               "Attempting to create a dependent instance time without "
    179               "reference to the creating SMILTimeValueSpec object.");
    180    if (!mCreator) return;
    181 
    182    aBaseInterval->AddDependentTime(*this);
    183  }
    184 
    185  mBaseInterval = aBaseInterval;
    186 }
    187 
    188 }  // namespace mozilla