dom/smil/SMILInstanceTime.cpp

   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