dom/smil/nsSMILTimedElement.cpp
author Mike Shal <mshal@mozilla.com>
Thu, 24 Aug 2017 22:52:01 -0400
changeset 434519 cb773c661e0ca0bf297e977343076bef34411523
parent 420043 0acc77eb92c6372cb73f441d2753c77068d87c2f
child 435808 67a8e12324569dd730347187e2ffccae486c758b
permissions -rw-r--r--
Bug 1402012 - Update buildconfig.py to use PartialConfigEnvironment; r=glandium By using the PartialConfigEnvironment, the clients of buildconfig will depend on config.statusd/ files instead of config.status directly. Clients can access substs and defines using buildconfig.substs['FOO'] or buildconfig.defines['BAR'], and then collect file-level dependencies for make using buildconfig.get_dependencies(). All GENERATED_FILES rules already make use of this because file_generate.py automatically includes these dependencies (along with all python modules loaded). As a result of this commit, re-running configure will no longer cause the world to be rebuilt. Although config.status is updated, no build steps use config.status directly and instead depend on values in config.statusd/, which are written with FileAvoidWrite. Since those files are not official targets according to the make backend, make won't try to continually rebuild the backend when those files are out of date. And since they are FileAvoidWrite, make will only re-run dependent steps if the actual configure value has changed. As a result of using JSON to load data from the config.statusd directory, substs can be unicode (instead of a bare string type). generate_certdata.py converts the subst manually to a string so the value can be exported to the environment without issue on Windows. Additionally, patching the buildconfig.substs dict no longer works, so the unit-symbolstore.py test was modified to patch the underlying buildconfig.substs._dict instead. The other files that needed to be modified make use of all the defines for the preprocessor. Those that are used during 'mach build' now use buildconfig.defines['ALLDEFINES'], which maps to a special FileAvoidWrite file generated for the PartialConfigEnvironment. MozReview-Commit-ID: 2pJ4s3TVeS8

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/DebugOnly.h"

#include "mozilla/ContentEvents.h"
#include "mozilla/EventDispatcher.h"
#include "mozilla/dom/SVGAnimationElement.h"
#include "mozilla/TaskCategory.h"
#include "nsAutoPtr.h"
#include "nsSMILTimedElement.h"
#include "nsAttrValueInlines.h"
#include "nsSMILAnimationFunction.h"
#include "nsSMILTimeValue.h"
#include "nsSMILTimeValueSpec.h"
#include "nsSMILInstanceTime.h"
#include "nsSMILParserUtils.h"
#include "nsSMILTimeContainer.h"
#include "nsGkAtoms.h"
#include "nsReadableUtils.h"
#include "nsMathUtils.h"
#include "nsThreadUtils.h"
#include "nsIPresShell.h"
#include "prdtoa.h"
#include "plstr.h"
#include "prtime.h"
#include "nsString.h"
#include "mozilla/AutoRestore.h"
#include "nsCharSeparatedTokenizer.h"
#include <algorithm>

using namespace mozilla;
using namespace mozilla::dom;

//----------------------------------------------------------------------
// Helper class: InstanceTimeComparator

// Upon inserting an instance time into one of our instance time lists we assign
// it a serial number. This allows us to sort the instance times in such a way
// that where we have several equal instance times, the ones added later will
// sort later. This means that when we call UpdateCurrentInterval during the
// waiting state we won't unnecessarily change the begin instance.
//
// The serial number also means that every instance time has an unambiguous
// position in the array so we can use RemoveElementSorted and the like.
bool
nsSMILTimedElement::InstanceTimeComparator::Equals(
    const nsSMILInstanceTime* aElem1,
    const nsSMILInstanceTime* aElem2) const
{
  MOZ_ASSERT(aElem1 && aElem2,
             "Trying to compare null instance time pointers");
  MOZ_ASSERT(aElem1->Serial() && aElem2->Serial(),
             "Instance times have not been assigned serial numbers");
  MOZ_ASSERT(aElem1 == aElem2 || aElem1->Serial() != aElem2->Serial(),
             "Serial numbers are not unique");

  return aElem1->Serial() == aElem2->Serial();
}

bool
nsSMILTimedElement::InstanceTimeComparator::LessThan(
    const nsSMILInstanceTime* aElem1,
    const nsSMILInstanceTime* aElem2) const
{
  MOZ_ASSERT(aElem1 && aElem2,
             "Trying to compare null instance time pointers");
  MOZ_ASSERT(aElem1->Serial() && aElem2->Serial(),
             "Instance times have not been assigned serial numbers");

  int8_t cmp = aElem1->Time().CompareTo(aElem2->Time());
  return cmp == 0 ? aElem1->Serial() < aElem2->Serial() : cmp < 0;
}

//----------------------------------------------------------------------
// Helper class: AsyncTimeEventRunner

namespace
{
  class AsyncTimeEventRunner : public Runnable
  {
  protected:
    RefPtr<nsIContent> mTarget;
    EventMessage         mMsg;
    int32_t              mDetail;

  public:
    AsyncTimeEventRunner(nsIContent* aTarget,
                         EventMessage aMsg,
                         int32_t aDetail)
      : mozilla::Runnable("AsyncTimeEventRunner")
      , mTarget(aTarget)
      , mMsg(aMsg)
      , mDetail(aDetail)
    {
    }

    NS_IMETHOD Run() override
    {
      InternalSMILTimeEvent event(true, mMsg);
      event.mDetail = mDetail;

      nsPresContext* context = nullptr;
      nsIDocument* doc = mTarget->GetUncomposedDoc();
      if (doc) {
        nsCOMPtr<nsIPresShell> shell = doc->GetShell();
        if (shell) {
          context = shell->GetPresContext();
        }
      }

      return EventDispatcher::Dispatch(mTarget, context, &event);
    }
  };
} // namespace

//----------------------------------------------------------------------
// Helper class: AutoIntervalUpdateBatcher

// Stack-based helper class to set the mDeferIntervalUpdates flag on an
// nsSMILTimedElement and perform the UpdateCurrentInterval when the object is
// destroyed.
//
// If several of these objects are allocated on the stack, the update will not
// be performed until the last object for a given nsSMILTimedElement is
// destroyed.
class MOZ_STACK_CLASS nsSMILTimedElement::AutoIntervalUpdateBatcher
{
public:
  explicit AutoIntervalUpdateBatcher(nsSMILTimedElement& aTimedElement)
    : mTimedElement(aTimedElement),
      mDidSetFlag(!aTimedElement.mDeferIntervalUpdates)
  {
    mTimedElement.mDeferIntervalUpdates = true;
  }

  ~AutoIntervalUpdateBatcher()
  {
    if (!mDidSetFlag)
      return;

    mTimedElement.mDeferIntervalUpdates = false;

    if (mTimedElement.mDoDeferredUpdate) {
      mTimedElement.mDoDeferredUpdate = false;
      mTimedElement.UpdateCurrentInterval();
    }
  }

private:
  nsSMILTimedElement& mTimedElement;
  bool mDidSetFlag;
};

//----------------------------------------------------------------------
// Helper class: AutoIntervalUpdater

// Stack-based helper class to call UpdateCurrentInterval when it is destroyed
// which helps avoid bugs where we forget to call UpdateCurrentInterval in the
// case of early returns (e.g. due to parse errors).
//
// This can be safely used in conjunction with AutoIntervalUpdateBatcher; any
// calls to UpdateCurrentInterval made by this class will simply be deferred if
// there is an AutoIntervalUpdateBatcher on the stack.
class MOZ_STACK_CLASS nsSMILTimedElement::AutoIntervalUpdater
{
public:
  explicit AutoIntervalUpdater(nsSMILTimedElement& aTimedElement)
    : mTimedElement(aTimedElement) { }

  ~AutoIntervalUpdater()
  {
    mTimedElement.UpdateCurrentInterval();
  }

private:
  nsSMILTimedElement& mTimedElement;
};

//----------------------------------------------------------------------
// Templated helper functions

// Selectively remove elements from an array of type
// nsTArray<RefPtr<nsSMILInstanceTime> > with O(n) performance.
template <class TestFunctor>
void
nsSMILTimedElement::RemoveInstanceTimes(InstanceTimeList& aArray,
                                        TestFunctor& aTest)
{
  InstanceTimeList newArray;
  for (uint32_t i = 0; i < aArray.Length(); ++i) {
    nsSMILInstanceTime* item = aArray[i].get();
    if (aTest(item, i)) {
      // As per bugs 665334 and 669225 we should be careful not to remove the
      // instance time that corresponds to the previous interval's end time.
      //
      // Most functors supplied here fulfil this condition by checking if the
      // instance time is marked as "ShouldPreserve" and if so, not deleting it.
      //
      // However, when filtering instance times, we sometimes need to drop even
      // instance times marked as "ShouldPreserve". In that case we take special
      // care not to delete the end instance time of the previous interval.
      MOZ_ASSERT(!GetPreviousInterval() || item != GetPreviousInterval()->End(),
                 "Removing end instance time of previous interval");
      item->Unlink();
    } else {
      newArray.AppendElement(item);
    }
  }
  aArray.Clear();
  aArray.SwapElements(newArray);
}

//----------------------------------------------------------------------
// Static members

const nsAttrValue::EnumTable nsSMILTimedElement::sFillModeTable[] = {
      {"remove", FILL_REMOVE},
      {"freeze", FILL_FREEZE},
      {nullptr, 0}
};

const nsAttrValue::EnumTable nsSMILTimedElement::sRestartModeTable[] = {
      {"always", RESTART_ALWAYS},
      {"whenNotActive", RESTART_WHENNOTACTIVE},
      {"never", RESTART_NEVER},
      {nullptr, 0}
};

const nsSMILMilestone nsSMILTimedElement::sMaxMilestone(INT64_MAX, false);

// The thresholds at which point we start filtering intervals and instance times
// indiscriminately.
// See FilterIntervals and FilterInstanceTimes.
const uint8_t nsSMILTimedElement::sMaxNumIntervals = 20;
const uint8_t nsSMILTimedElement::sMaxNumInstanceTimes = 100;

// Detect if we arrive in some sort of undetected recursive syncbase dependency
// relationship
const uint8_t nsSMILTimedElement::sMaxUpdateIntervalRecursionDepth = 20;

//----------------------------------------------------------------------
// Ctor, dtor

nsSMILTimedElement::nsSMILTimedElement()
:
  mAnimationElement(nullptr),
  mFillMode(FILL_REMOVE),
  mRestartMode(RESTART_ALWAYS),
  mInstanceSerialIndex(0),
  mClient(nullptr),
  mCurrentInterval(nullptr),
  mCurrentRepeatIteration(0),
  mPrevRegisteredMilestone(sMaxMilestone),
  mElementState(STATE_STARTUP),
  mSeekState(SEEK_NOT_SEEKING),
  mDeferIntervalUpdates(false),
  mDoDeferredUpdate(false),
  mIsDisabled(false),
  mDeleteCount(0),
  mUpdateIntervalRecursionDepth(0)
{
  mSimpleDur.SetIndefinite();
  mMin.SetMillis(0L);
  mMax.SetIndefinite();
}

nsSMILTimedElement::~nsSMILTimedElement()
{
  // Unlink all instance times from dependent intervals
  for (uint32_t i = 0; i < mBeginInstances.Length(); ++i) {
    mBeginInstances[i]->Unlink();
  }
  mBeginInstances.Clear();
  for (uint32_t i = 0; i < mEndInstances.Length(); ++i) {
    mEndInstances[i]->Unlink();
  }
  mEndInstances.Clear();

  // Notify anyone listening to our intervals that they're gone
  // (We shouldn't get any callbacks from this because all our instance times
  // are now disassociated with any intervals)
  ClearIntervals();

  // The following assertions are important in their own right (for checking
  // correct behavior) but also because AutoIntervalUpdateBatcher holds pointers
  // to class so if they fail there's the possibility we might have dangling
  // pointers.
  MOZ_ASSERT(!mDeferIntervalUpdates,
             "Interval updates should no longer be blocked when an "
             "nsSMILTimedElement disappears");
  MOZ_ASSERT(!mDoDeferredUpdate,
             "There should no longer be any pending updates when an "
             "nsSMILTimedElement disappears");
}

void
nsSMILTimedElement::SetAnimationElement(SVGAnimationElement* aElement)
{
  MOZ_ASSERT(aElement, "NULL owner element");
  MOZ_ASSERT(!mAnimationElement, "Re-setting owner");
  mAnimationElement = aElement;
}

nsSMILTimeContainer*
nsSMILTimedElement::GetTimeContainer()
{
  return mAnimationElement ? mAnimationElement->GetTimeContainer() : nullptr;
}

dom::Element*
nsSMILTimedElement::GetTargetElement()
{
  return mAnimationElement ?
      mAnimationElement->GetTargetElementContent() :
      nullptr;
}

//----------------------------------------------------------------------
// nsIDOMElementTimeControl methods
//
// The definition of the ElementTimeControl interface differs between SMIL
// Animation and SVG 1.1. In SMIL Animation all methods have a void return
// type and the new instance time is simply added to the list and restart
// semantics are applied as with any other instance time. In the SVG definition
// the methods return a bool depending on the restart mode.
//
// This inconsistency has now been addressed by an erratum in SVG 1.1:
//
// http://www.w3.org/2003/01/REC-SVG11-20030114-errata#elementtimecontrol-interface
//
// which favours the definition in SMIL, i.e. instance times are just added
// without first checking the restart mode.

nsresult
nsSMILTimedElement::BeginElementAt(double aOffsetSeconds)
{
  nsSMILTimeContainer* container = GetTimeContainer();
  if (!container)
    return NS_ERROR_FAILURE;

  nsSMILTime currentTime = container->GetCurrentTime();
  return AddInstanceTimeFromCurrentTime(currentTime, aOffsetSeconds, true);
}

nsresult
nsSMILTimedElement::EndElementAt(double aOffsetSeconds)
{
  nsSMILTimeContainer* container = GetTimeContainer();
  if (!container)
    return NS_ERROR_FAILURE;

  nsSMILTime currentTime = container->GetCurrentTime();
  return AddInstanceTimeFromCurrentTime(currentTime, aOffsetSeconds, false);
}

//----------------------------------------------------------------------
// nsSVGAnimationElement methods

nsSMILTimeValue
nsSMILTimedElement::GetStartTime() const
{
  return mElementState == STATE_WAITING || mElementState == STATE_ACTIVE
         ? mCurrentInterval->Begin()->Time()
         : nsSMILTimeValue();
}

//----------------------------------------------------------------------
// Hyperlinking support

nsSMILTimeValue
nsSMILTimedElement::GetHyperlinkTime() const
{
  nsSMILTimeValue hyperlinkTime; // Default ctor creates unresolved time

  if (mElementState == STATE_ACTIVE) {
    hyperlinkTime = mCurrentInterval->Begin()->Time();
  } else if (!mBeginInstances.IsEmpty()) {
    hyperlinkTime = mBeginInstances[0]->Time();
  }

  return hyperlinkTime;
}

//----------------------------------------------------------------------
// nsSMILTimedElement

void
nsSMILTimedElement::AddInstanceTime(nsSMILInstanceTime* aInstanceTime,
                                    bool aIsBegin)
{
  MOZ_ASSERT(aInstanceTime, "Attempting to add null instance time");

  // Event-sensitivity: If an element is not active (but the parent time
  // container is), then events are only handled for begin specifications.
  if (mElementState != STATE_ACTIVE && !aIsBegin &&
      aInstanceTime->IsDynamic())
  {
    // No need to call Unlink here--dynamic instance times shouldn't be linked
    // to anything that's going to miss them
    MOZ_ASSERT(!aInstanceTime->GetBaseInterval(),
               "Dynamic instance time has a base interval--we probably need "
               "to unlink it if we're not going to use it");
    return;
  }

  aInstanceTime->SetSerial(++mInstanceSerialIndex);
  InstanceTimeList& instanceList = aIsBegin ? mBeginInstances : mEndInstances;
  RefPtr<nsSMILInstanceTime>* inserted =
    instanceList.InsertElementSorted(aInstanceTime, InstanceTimeComparator());
  if (!inserted) {
    NS_WARNING("Insufficient memory to insert instance time");
    return;
  }

  UpdateCurrentInterval();
}

void
nsSMILTimedElement::UpdateInstanceTime(nsSMILInstanceTime* aInstanceTime,
                                       nsSMILTimeValue& aUpdatedTime,
                                       bool aIsBegin)
{
  MOZ_ASSERT(aInstanceTime, "Attempting to update null instance time");

  // The reason we update the time here and not in the nsSMILTimeValueSpec is
  // that it means we *could* re-sort more efficiently by doing a sorted remove
  // and insert but currently this doesn't seem to be necessary given how
  // infrequently we get these change notices.
  aInstanceTime->DependentUpdate(aUpdatedTime);
  InstanceTimeList& instanceList = aIsBegin ? mBeginInstances : mEndInstances;
  instanceList.Sort(InstanceTimeComparator());

  // Generally speaking, UpdateCurrentInterval makes changes to the current
  // interval and sends changes notices itself. However, in this case because
  // instance times are shared between the instance time list and the intervals
  // we are effectively changing the current interval outside
  // UpdateCurrentInterval so we need to explicitly signal that we've made
  // a change.
  //
  // This wouldn't be necessary if we cloned instance times on adding them to
  // the current interval but this introduces other complications (particularly
  // detecting which instance time is being used to define the begin of the
  // current interval when doing a Reset).
  bool changedCurrentInterval = mCurrentInterval &&
    (mCurrentInterval->Begin() == aInstanceTime ||
     mCurrentInterval->End() == aInstanceTime);

  UpdateCurrentInterval(changedCurrentInterval);
}

void
nsSMILTimedElement::RemoveInstanceTime(nsSMILInstanceTime* aInstanceTime,
                                       bool aIsBegin)
{
  MOZ_ASSERT(aInstanceTime, "Attempting to remove null instance time");

  // If the instance time should be kept (because it is or was the fixed end
  // point of an interval) then just disassociate it from the creator.
  if (aInstanceTime->ShouldPreserve()) {
    aInstanceTime->Unlink();
    return;
  }

  InstanceTimeList& instanceList = aIsBegin ? mBeginInstances : mEndInstances;
  mozilla::DebugOnly<bool> found =
    instanceList.RemoveElementSorted(aInstanceTime, InstanceTimeComparator());
  MOZ_ASSERT(found, "Couldn't find instance time to delete");

  UpdateCurrentInterval();
}

namespace
{
  class MOZ_STACK_CLASS RemoveByCreator
  {
  public:
    explicit RemoveByCreator(const nsSMILTimeValueSpec* aCreator) : mCreator(aCreator)
    { }

    bool operator()(nsSMILInstanceTime* aInstanceTime, uint32_t /*aIndex*/)
    {
      if (aInstanceTime->GetCreator() != mCreator)
        return false;

      // If the instance time should be kept (because it is or was the fixed end
      // point of an interval) then just disassociate it from the creator.
      if (aInstanceTime->ShouldPreserve()) {
        aInstanceTime->Unlink();
        return false;
      }

      return true;
    }

  private:
    const nsSMILTimeValueSpec* mCreator;
  };
} // namespace

void
nsSMILTimedElement::RemoveInstanceTimesForCreator(
    const nsSMILTimeValueSpec* aCreator, bool aIsBegin)
{
  MOZ_ASSERT(aCreator, "Creator not set");

  InstanceTimeList& instances = aIsBegin ? mBeginInstances : mEndInstances;
  RemoveByCreator removeByCreator(aCreator);
  RemoveInstanceTimes(instances, removeByCreator);

  UpdateCurrentInterval();
}

void
nsSMILTimedElement::SetTimeClient(nsSMILAnimationFunction* aClient)
{
  //
  // No need to check for nullptr. A nullptr parameter simply means to remove the
  // previous client which we do by setting to nullptr anyway.
  //

  mClient = aClient;
}

void
nsSMILTimedElement::SampleAt(nsSMILTime aContainerTime)
{
  if (mIsDisabled)
    return;

  // Milestones are cleared before a sample
  mPrevRegisteredMilestone = sMaxMilestone;

  DoSampleAt(aContainerTime, false);
}

void
nsSMILTimedElement::SampleEndAt(nsSMILTime aContainerTime)
{
  if (mIsDisabled)
    return;

  // Milestones are cleared before a sample
  mPrevRegisteredMilestone = sMaxMilestone;

  // If the current interval changes, we don't bother trying to remove any old
  // milestones we'd registered. So it's possible to get a call here to end an
  // interval at a time that no longer reflects the end of the current interval.
  //
  // For now we just check that we're actually in an interval but note that the
  // initial sample we use to initialise the model is an end sample. This is
  // because we want to resolve all the instance times before committing to an
  // initial interval. Therefore an end sample from the startup state is also
  // acceptable.
  if (mElementState == STATE_ACTIVE || mElementState == STATE_STARTUP) {
    DoSampleAt(aContainerTime, true); // End sample
  } else {
    // Even if this was an unnecessary milestone sample we want to be sure that
    // our next real milestone is registered.
    RegisterMilestone();
  }
}

void
nsSMILTimedElement::DoSampleAt(nsSMILTime aContainerTime, bool aEndOnly)
{
  MOZ_ASSERT(mAnimationElement,
             "Got sample before being registered with an animation element");
  MOZ_ASSERT(GetTimeContainer(),
             "Got sample without being registered with a time container");

  // This could probably happen if we later implement externalResourcesRequired
  // (bug 277955) and whilst waiting for those resources (and the animation to
  // start) we transfer a node from another document fragment that has already
  // started. In such a case we might receive milestone samples registered with
  // the already active container.
  if (GetTimeContainer()->IsPausedByType(nsSMILTimeContainer::PAUSE_BEGIN))
    return;

  // We use an end-sample to start animation since an end-sample lets us
  // tentatively create an interval without committing to it (by transitioning
  // to the ACTIVE state) and this is necessary because we might have
  // dependencies on other animations that are yet to start. After these
  // other animations start, it may be necessary to revise our initial interval.
  //
  // However, sometimes instead of an end-sample we can get a regular sample
  // during STARTUP state. This can happen, for example, if we register
  // a milestone before time t=0 and are then re-bound to the tree (which sends
  // us back to the STARTUP state). In such a case we should just ignore the
  // sample and wait for our real initial sample which will be an end-sample.
  if (mElementState == STATE_STARTUP && !aEndOnly)
    return;

  bool finishedSeek = false;
  if (GetTimeContainer()->IsSeeking() && mSeekState == SEEK_NOT_SEEKING) {
    mSeekState = mElementState == STATE_ACTIVE ?
                 SEEK_FORWARD_FROM_ACTIVE :
                 SEEK_FORWARD_FROM_INACTIVE;
  } else if (mSeekState != SEEK_NOT_SEEKING &&
             !GetTimeContainer()->IsSeeking()) {
    finishedSeek = true;
  }

  bool            stateChanged;
  nsSMILTimeValue sampleTime(aContainerTime);

  do {
#ifdef DEBUG
    // Check invariant
    if (mElementState == STATE_STARTUP || mElementState == STATE_POSTACTIVE) {
      MOZ_ASSERT(!mCurrentInterval,
                 "Shouldn't have current interval in startup or postactive "
                 "states");
    } else {
      MOZ_ASSERT(mCurrentInterval,
                 "Should have current interval in waiting and active states");
    }
#endif

    stateChanged = false;

    switch (mElementState)
    {
    case STATE_STARTUP:
      {
        nsSMILInterval firstInterval;
        mElementState = GetNextInterval(nullptr, nullptr, nullptr, firstInterval)
         ? STATE_WAITING
         : STATE_POSTACTIVE;
        stateChanged = true;
        if (mElementState == STATE_WAITING) {
          mCurrentInterval = new nsSMILInterval(firstInterval);
          NotifyNewInterval();
        }
      }
      break;

    case STATE_WAITING:
      {
        if (mCurrentInterval->Begin()->Time() <= sampleTime) {
          mElementState = STATE_ACTIVE;
          mCurrentInterval->FixBegin();
          if (mClient) {
            mClient->Activate(mCurrentInterval->Begin()->Time().GetMillis());
          }
          if (mSeekState == SEEK_NOT_SEEKING) {
            FireTimeEventAsync(eSMILBeginEvent, 0);
          }
          if (HasPlayed()) {
            Reset(); // Apply restart behaviour
            // The call to Reset() may mean that the end point of our current
            // interval should be changed and so we should update the interval
            // now. However, calling UpdateCurrentInterval could result in the
            // interval getting deleted (perhaps through some web of syncbase
            // dependencies) therefore we make updating the interval the last
            // thing we do. There is no guarantee that mCurrentInterval is set
            // after this.
            UpdateCurrentInterval();
          }
          stateChanged = true;
        }
      }
      break;

    case STATE_ACTIVE:
      {
        // Ending early will change the interval but we don't notify dependents
        // of the change until we have closed off the current interval (since we
        // don't want dependencies to un-end our early end).
        bool didApplyEarlyEnd = ApplyEarlyEnd(sampleTime);

        if (mCurrentInterval->End()->Time() <= sampleTime) {
          nsSMILInterval newInterval;
          mElementState =
            GetNextInterval(mCurrentInterval, nullptr, nullptr, newInterval)
            ? STATE_WAITING
            : STATE_POSTACTIVE;
          if (mClient) {
            mClient->Inactivate(mFillMode == FILL_FREEZE);
          }
          mCurrentInterval->FixEnd();
          if (mSeekState == SEEK_NOT_SEEKING) {
            FireTimeEventAsync(eSMILEndEvent, 0);
          }
          mCurrentRepeatIteration = 0;
          mOldIntervals.AppendElement(mCurrentInterval.forget());
          SampleFillValue();
          if (mElementState == STATE_WAITING) {
            mCurrentInterval = new nsSMILInterval(newInterval);
          }
          // We are now in a consistent state to dispatch notifications
          if (didApplyEarlyEnd) {
            NotifyChangedInterval(
                mOldIntervals[mOldIntervals.Length() - 1], false, true);
          }
          if (mElementState == STATE_WAITING) {
            NotifyNewInterval();
          }
          FilterHistory();
          stateChanged = true;
        } else {
          MOZ_ASSERT(!didApplyEarlyEnd,
                     "We got an early end, but didn't end");
          nsSMILTime beginTime = mCurrentInterval->Begin()->Time().GetMillis();
          NS_ASSERTION(aContainerTime >= beginTime,
                       "Sample time should not precede current interval");
          nsSMILTime activeTime = aContainerTime - beginTime;

          // The 'min' attribute can cause the active interval to be longer than
          // the 'repeating interval'.
          // In that extended period we apply the fill mode.
          if (GetRepeatDuration() <= nsSMILTimeValue(activeTime)) {
            if (mClient && mClient->IsActive()) {
              mClient->Inactivate(mFillMode == FILL_FREEZE);
            }
            SampleFillValue();
          } else {
            SampleSimpleTime(activeTime);

            // We register our repeat times as milestones (except when we're
            // seeking) so we should get a sample at exactly the time we repeat.
            // (And even when we are seeking we want to update
            // mCurrentRepeatIteration so we do that first before testing the
            // seek state.)
            uint32_t prevRepeatIteration = mCurrentRepeatIteration;
            if (
              ActiveTimeToSimpleTime(activeTime, mCurrentRepeatIteration)==0 &&
              mCurrentRepeatIteration != prevRepeatIteration &&
              mCurrentRepeatIteration &&
              mSeekState == SEEK_NOT_SEEKING) {
              FireTimeEventAsync(eSMILRepeatEvent,
                            static_cast<int32_t>(mCurrentRepeatIteration));
            }
          }
        }
      }
      break;

    case STATE_POSTACTIVE:
      break;
    }

  // Generally we continue driving the state machine so long as we have changed
  // state. However, for end samples we only drive the state machine as far as
  // the waiting or postactive state because we don't want to commit to any new
  // interval (by transitioning to the active state) until all the end samples
  // have finished and we then have complete information about the available
  // instance times upon which to base our next interval.
  } while (stateChanged && (!aEndOnly || (mElementState != STATE_WAITING &&
                                          mElementState != STATE_POSTACTIVE)));

  if (finishedSeek) {
    DoPostSeek();
  }
  RegisterMilestone();
}

void
nsSMILTimedElement::HandleContainerTimeChange()
{
  // In future we could possibly introduce a separate change notice for time
  // container changes and only notify those dependents who live in other time
  // containers. For now we don't bother because when we re-resolve the time in
  // the nsSMILTimeValueSpec we'll check if anything has changed and if not, we
  // won't go any further.
  if (mElementState == STATE_WAITING || mElementState == STATE_ACTIVE) {
    NotifyChangedInterval(mCurrentInterval, false, false);
  }
}

namespace
{
  bool
  RemoveNonDynamic(nsSMILInstanceTime* aInstanceTime)
  {
    // Generally dynamically-generated instance times (DOM calls, event-based
    // times) are not associated with their creator nsSMILTimeValueSpec since
    // they may outlive them.
    MOZ_ASSERT(!aInstanceTime->IsDynamic() || !aInstanceTime->GetCreator(),
               "Dynamic instance time should be unlinked from its creator");
    return !aInstanceTime->IsDynamic() && !aInstanceTime->ShouldPreserve();
  }
} // namespace

void
nsSMILTimedElement::Rewind()
{
  MOZ_ASSERT(mAnimationElement,
             "Got rewind request before being attached to an animation "
             "element");

  // It's possible to get a rewind request whilst we're already in the middle of
  // a backwards seek. This can happen when we're performing tree surgery and
  // seeking containers at the same time because we can end up requesting
  // a local rewind on an element after binding it to a new container and then
  // performing a rewind on that container as a whole without sampling in
  // between.
  //
  // However, it should currently be impossible to get a rewind in the middle of
  // a forwards seek since forwards seeks are detected and processed within the
  // same (re)sample.
  if (mSeekState == SEEK_NOT_SEEKING) {
    mSeekState = mElementState == STATE_ACTIVE ?
                 SEEK_BACKWARD_FROM_ACTIVE :
                 SEEK_BACKWARD_FROM_INACTIVE;
  }
  MOZ_ASSERT(mSeekState == SEEK_BACKWARD_FROM_INACTIVE ||
             mSeekState == SEEK_BACKWARD_FROM_ACTIVE,
             "Rewind in the middle of a forwards seek?");

  ClearTimingState(RemoveNonDynamic);
  RebuildTimingState(RemoveNonDynamic);

  MOZ_ASSERT(!mCurrentInterval,
             "Current interval is set at end of rewind");
}

namespace
{
  bool
  RemoveAll(nsSMILInstanceTime* aInstanceTime)
  {
    return true;
  }
} // namespace

bool
nsSMILTimedElement::SetIsDisabled(bool aIsDisabled)
{
  if (mIsDisabled == aIsDisabled)
    return false;

  if (aIsDisabled) {
    mIsDisabled = true;
    ClearTimingState(RemoveAll);
  } else {
    RebuildTimingState(RemoveAll);
    mIsDisabled = false;
  }
  return true;
}

namespace
{
  bool
  RemoveNonDOM(nsSMILInstanceTime* aInstanceTime)
  {
    return !aInstanceTime->FromDOM() && !aInstanceTime->ShouldPreserve();
  }
} // namespace

bool
nsSMILTimedElement::SetAttr(nsIAtom* aAttribute, const nsAString& aValue,
                            nsAttrValue& aResult,
                            Element* aContextNode,
                            nsresult* aParseResult)
{
  bool foundMatch = true;
  nsresult parseResult = NS_OK;

  if (aAttribute == nsGkAtoms::begin) {
    parseResult = SetBeginSpec(aValue, aContextNode, RemoveNonDOM);
  } else if (aAttribute == nsGkAtoms::dur) {
    parseResult = SetSimpleDuration(aValue);
  } else if (aAttribute == nsGkAtoms::end) {
    parseResult = SetEndSpec(aValue, aContextNode, RemoveNonDOM);
  } else if (aAttribute == nsGkAtoms::fill) {
    parseResult = SetFillMode(aValue);
  } else if (aAttribute == nsGkAtoms::max) {
    parseResult = SetMax(aValue);
  } else if (aAttribute == nsGkAtoms::min) {
    parseResult = SetMin(aValue);
  } else if (aAttribute == nsGkAtoms::repeatCount) {
    parseResult = SetRepeatCount(aValue);
  } else if (aAttribute == nsGkAtoms::repeatDur) {
    parseResult = SetRepeatDur(aValue);
  } else if (aAttribute == nsGkAtoms::restart) {
    parseResult = SetRestart(aValue);
  } else {
    foundMatch = false;
  }

  if (foundMatch) {
    aResult.SetTo(aValue);
    if (aParseResult) {
      *aParseResult = parseResult;
    }
  }

  return foundMatch;
}

bool
nsSMILTimedElement::UnsetAttr(nsIAtom* aAttribute)
{
  bool foundMatch = true;

  if (aAttribute == nsGkAtoms::begin) {
    UnsetBeginSpec(RemoveNonDOM);
  } else if (aAttribute == nsGkAtoms::dur) {
    UnsetSimpleDuration();
  } else if (aAttribute == nsGkAtoms::end) {
    UnsetEndSpec(RemoveNonDOM);
  } else if (aAttribute == nsGkAtoms::fill) {
    UnsetFillMode();
  } else if (aAttribute == nsGkAtoms::max) {
    UnsetMax();
  } else if (aAttribute == nsGkAtoms::min) {
    UnsetMin();
  } else if (aAttribute == nsGkAtoms::repeatCount) {
    UnsetRepeatCount();
  } else if (aAttribute == nsGkAtoms::repeatDur) {
    UnsetRepeatDur();
  } else if (aAttribute == nsGkAtoms::restart) {
    UnsetRestart();
  } else {
    foundMatch = false;
  }

  return foundMatch;
}

//----------------------------------------------------------------------
// Setters and unsetters

nsresult
nsSMILTimedElement::SetBeginSpec(const nsAString& aBeginSpec,
                                 Element* aContextNode,
                                 RemovalTestFunction aRemove)
{
  return SetBeginOrEndSpec(aBeginSpec, aContextNode, true /*isBegin*/,
                           aRemove);
}

void
nsSMILTimedElement::UnsetBeginSpec(RemovalTestFunction aRemove)
{
  ClearSpecs(mBeginSpecs, mBeginInstances, aRemove);
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetEndSpec(const nsAString& aEndSpec,
                               Element* aContextNode,
                               RemovalTestFunction aRemove)
{
  return SetBeginOrEndSpec(aEndSpec, aContextNode, false /*!isBegin*/,
                           aRemove);
}

void
nsSMILTimedElement::UnsetEndSpec(RemovalTestFunction aRemove)
{
  ClearSpecs(mEndSpecs, mEndInstances, aRemove);
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetSimpleDuration(const nsAString& aDurSpec)
{
  // Update the current interval before returning
  AutoIntervalUpdater updater(*this);

  nsSMILTimeValue duration;
  const nsAString& dur = nsSMILParserUtils::TrimWhitespace(aDurSpec);

  // SVG-specific: "For SVG's animation elements, if "media" is specified, the
  // attribute will be ignored." (SVG 1.1, section 19.2.6)
  if (dur.EqualsLiteral("media") || dur.EqualsLiteral("indefinite")) {
    duration.SetIndefinite();
  } else {
    if (!nsSMILParserUtils::ParseClockValue(dur, &duration) ||
        duration.GetMillis() == 0L) {
      mSimpleDur.SetIndefinite();
      return NS_ERROR_FAILURE;
    }
  }
  // mSimpleDur should never be unresolved. ParseClockValue will either set
  // duration to resolved or will return false.
  MOZ_ASSERT(duration.IsResolved(),
             "Setting unresolved simple duration");

  mSimpleDur = duration;

  return NS_OK;
}

void
nsSMILTimedElement::UnsetSimpleDuration()
{
  mSimpleDur.SetIndefinite();
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetMin(const nsAString& aMinSpec)
{
  // Update the current interval before returning
  AutoIntervalUpdater updater(*this);

  nsSMILTimeValue duration;
  const nsAString& min = nsSMILParserUtils::TrimWhitespace(aMinSpec);

  if (min.EqualsLiteral("media")) {
    duration.SetMillis(0L);
  } else {
    if (!nsSMILParserUtils::ParseClockValue(min, &duration)) {
      mMin.SetMillis(0L);
      return NS_ERROR_FAILURE;
    }
  }

  MOZ_ASSERT(duration.GetMillis() >= 0L, "Invalid duration");

  mMin = duration;

  return NS_OK;
}

void
nsSMILTimedElement::UnsetMin()
{
  mMin.SetMillis(0L);
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetMax(const nsAString& aMaxSpec)
{
  // Update the current interval before returning
  AutoIntervalUpdater updater(*this);

  nsSMILTimeValue duration;
  const nsAString& max = nsSMILParserUtils::TrimWhitespace(aMaxSpec);

  if (max.EqualsLiteral("media") || max.EqualsLiteral("indefinite")) {
    duration.SetIndefinite();
  } else {
    if (!nsSMILParserUtils::ParseClockValue(max, &duration) ||
        duration.GetMillis() == 0L) {
      mMax.SetIndefinite();
      return NS_ERROR_FAILURE;
    }
    MOZ_ASSERT(duration.GetMillis() > 0L, "Invalid duration");
  }

  mMax = duration;

  return NS_OK;
}

void
nsSMILTimedElement::UnsetMax()
{
  mMax.SetIndefinite();
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetRestart(const nsAString& aRestartSpec)
{
  nsAttrValue temp;
  bool parseResult
    = temp.ParseEnumValue(aRestartSpec, sRestartModeTable, true);
  mRestartMode = parseResult
               ? nsSMILRestartMode(temp.GetEnumValue())
               : RESTART_ALWAYS;
  UpdateCurrentInterval();
  return parseResult ? NS_OK : NS_ERROR_FAILURE;
}

void
nsSMILTimedElement::UnsetRestart()
{
  mRestartMode = RESTART_ALWAYS;
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetRepeatCount(const nsAString& aRepeatCountSpec)
{
  // Update the current interval before returning
  AutoIntervalUpdater updater(*this);

  nsSMILRepeatCount newRepeatCount;

  if (nsSMILParserUtils::ParseRepeatCount(aRepeatCountSpec, newRepeatCount)) {
    mRepeatCount = newRepeatCount;
    return NS_OK;
  }
  mRepeatCount.Unset();
  return NS_ERROR_FAILURE;
}

void
nsSMILTimedElement::UnsetRepeatCount()
{
  mRepeatCount.Unset();
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetRepeatDur(const nsAString& aRepeatDurSpec)
{
  // Update the current interval before returning
  AutoIntervalUpdater updater(*this);

  nsSMILTimeValue duration;

  const nsAString& repeatDur =
    nsSMILParserUtils::TrimWhitespace(aRepeatDurSpec);

  if (repeatDur.EqualsLiteral("indefinite")) {
    duration.SetIndefinite();
  } else {
    if (!nsSMILParserUtils::ParseClockValue(repeatDur, &duration)) {
      mRepeatDur.SetUnresolved();
      return NS_ERROR_FAILURE;
    }
  }

  mRepeatDur = duration;

  return NS_OK;
}

void
nsSMILTimedElement::UnsetRepeatDur()
{
  mRepeatDur.SetUnresolved();
  UpdateCurrentInterval();
}

nsresult
nsSMILTimedElement::SetFillMode(const nsAString& aFillModeSpec)
{
  uint16_t previousFillMode = mFillMode;

  nsAttrValue temp;
  bool parseResult =
    temp.ParseEnumValue(aFillModeSpec, sFillModeTable, true);
  mFillMode = parseResult
            ? nsSMILFillMode(temp.GetEnumValue())
            : FILL_REMOVE;

  // Update fill mode of client
  if (mFillMode != previousFillMode && HasClientInFillRange()) {
    mClient->Inactivate(mFillMode == FILL_FREEZE);
    SampleFillValue();
  }

  return parseResult ? NS_OK : NS_ERROR_FAILURE;
}

void
nsSMILTimedElement::UnsetFillMode()
{
  uint16_t previousFillMode = mFillMode;
  mFillMode = FILL_REMOVE;
  if (previousFillMode == FILL_FREEZE && HasClientInFillRange()) {
    mClient->Inactivate(false);
  }
}

void
nsSMILTimedElement::AddDependent(nsSMILTimeValueSpec& aDependent)
{
  // There's probably no harm in attempting to register a dependent
  // nsSMILTimeValueSpec twice, but we're not expecting it to happen.
  MOZ_ASSERT(!mTimeDependents.GetEntry(&aDependent),
             "nsSMILTimeValueSpec is already registered as a dependency");
  mTimeDependents.PutEntry(&aDependent);

  // Add current interval. We could add historical intervals too but that would
  // cause unpredictable results since some intervals may have been filtered.
  // SMIL doesn't say what to do here so for simplicity and consistency we
  // simply add the current interval if there is one.
  //
  // It's not necessary to call SyncPauseTime since we're dealing with
  // historical instance times not newly added ones.
  if (mCurrentInterval) {
    aDependent.HandleNewInterval(*mCurrentInterval, GetTimeContainer());
  }
}

void
nsSMILTimedElement::RemoveDependent(nsSMILTimeValueSpec& aDependent)
{
  mTimeDependents.RemoveEntry(&aDependent);
}

bool
nsSMILTimedElement::IsTimeDependent(const nsSMILTimedElement& aOther) const
{
  const nsSMILInstanceTime* thisBegin = GetEffectiveBeginInstance();
  const nsSMILInstanceTime* otherBegin = aOther.GetEffectiveBeginInstance();

  if (!thisBegin || !otherBegin)
    return false;

  return thisBegin->IsDependentOn(*otherBegin);
}

void
nsSMILTimedElement::BindToTree(nsIContent* aContextNode)
{
  // Reset previously registered milestone since we may be registering with
  // a different time container now.
  mPrevRegisteredMilestone = sMaxMilestone;

  // If we were already active then clear all our timing information and start
  // afresh
  if (mElementState != STATE_STARTUP) {
    mSeekState = SEEK_NOT_SEEKING;
    Rewind();
  }

  // Scope updateBatcher to last only for the ResolveReferences calls:
  {
    AutoIntervalUpdateBatcher updateBatcher(*this);

    // Resolve references to other parts of the tree
    uint32_t count = mBeginSpecs.Length();
    for (uint32_t i = 0; i < count; ++i) {
      mBeginSpecs[i]->ResolveReferences(aContextNode);
    }

    count = mEndSpecs.Length();
    for (uint32_t j = 0; j < count; ++j) {
      mEndSpecs[j]->ResolveReferences(aContextNode);
    }
  }

  RegisterMilestone();
}

void
nsSMILTimedElement::HandleTargetElementChange(Element* aNewTarget)
{
  AutoIntervalUpdateBatcher updateBatcher(*this);

  uint32_t count = mBeginSpecs.Length();
  for (uint32_t i = 0; i < count; ++i) {
    mBeginSpecs[i]->HandleTargetElementChange(aNewTarget);
  }

  count = mEndSpecs.Length();
  for (uint32_t j = 0; j < count; ++j) {
    mEndSpecs[j]->HandleTargetElementChange(aNewTarget);
  }
}

void
nsSMILTimedElement::Traverse(nsCycleCollectionTraversalCallback* aCallback)
{
  uint32_t count = mBeginSpecs.Length();
  for (uint32_t i = 0; i < count; ++i) {
    nsSMILTimeValueSpec* beginSpec = mBeginSpecs[i];
    MOZ_ASSERT(beginSpec,
               "null nsSMILTimeValueSpec in list of begin specs");
    beginSpec->Traverse(aCallback);
  }

  count = mEndSpecs.Length();
  for (uint32_t j = 0; j < count; ++j) {
    nsSMILTimeValueSpec* endSpec = mEndSpecs[j];
    MOZ_ASSERT(endSpec, "null nsSMILTimeValueSpec in list of end specs");
    endSpec->Traverse(aCallback);
  }
}

void
nsSMILTimedElement::Unlink()
{
  AutoIntervalUpdateBatcher updateBatcher(*this);

  // Remove dependencies on other elements
  uint32_t count = mBeginSpecs.Length();
  for (uint32_t i = 0; i < count; ++i) {
    nsSMILTimeValueSpec* beginSpec = mBeginSpecs[i];
    MOZ_ASSERT(beginSpec,
               "null nsSMILTimeValueSpec in list of begin specs");
    beginSpec->Unlink();
  }

  count = mEndSpecs.Length();
  for (uint32_t j = 0; j < count; ++j) {
    nsSMILTimeValueSpec* endSpec = mEndSpecs[j];
    MOZ_ASSERT(endSpec, "null nsSMILTimeValueSpec in list of end specs");
    endSpec->Unlink();
  }

  ClearIntervals();

  // Make sure we don't notify other elements of new intervals
  mTimeDependents.Clear();
}

//----------------------------------------------------------------------
// Implementation helpers

nsresult
nsSMILTimedElement::SetBeginOrEndSpec(const nsAString& aSpec,
                                      Element* aContextNode,
                                      bool aIsBegin,
                                      RemovalTestFunction aRemove)
{
  TimeValueSpecList& timeSpecsList = aIsBegin ? mBeginSpecs : mEndSpecs;
  InstanceTimeList& instances = aIsBegin ? mBeginInstances : mEndInstances;

  ClearSpecs(timeSpecsList, instances, aRemove);

  AutoIntervalUpdateBatcher updateBatcher(*this);

  nsCharSeparatedTokenizer tokenizer(aSpec, ';');
  if (!tokenizer.hasMoreTokens()) { // Empty list
    return NS_ERROR_FAILURE;
  }

  nsresult rv = NS_OK;
  while (tokenizer.hasMoreTokens() && NS_SUCCEEDED(rv)) {
    nsAutoPtr<nsSMILTimeValueSpec>
      spec(new nsSMILTimeValueSpec(*this, aIsBegin));
    rv = spec->SetSpec(tokenizer.nextToken(), aContextNode);
    if (NS_SUCCEEDED(rv)) {
      timeSpecsList.AppendElement(spec.forget());
    }
  }

  if (NS_FAILED(rv)) {
    ClearSpecs(timeSpecsList, instances, aRemove);
  }

  return rv;
}

namespace
{
  // Adaptor functor for RemoveInstanceTimes that allows us to use function
  // pointers instead.
  // Without this we'd have to either templatize ClearSpecs and all its callers
  // or pass bool flags around to specify which removal function to use here.
  class MOZ_STACK_CLASS RemoveByFunction
  {
  public:
    explicit RemoveByFunction(nsSMILTimedElement::RemovalTestFunction aFunction)
      : mFunction(aFunction) { }
    bool operator()(nsSMILInstanceTime* aInstanceTime, uint32_t /*aIndex*/)
    {
      return mFunction(aInstanceTime);
    }

  private:
    nsSMILTimedElement::RemovalTestFunction mFunction;
  };
} // namespace

void
nsSMILTimedElement::ClearSpecs(TimeValueSpecList& aSpecs,
                               InstanceTimeList& aInstances,
                               RemovalTestFunction aRemove)
{
  AutoIntervalUpdateBatcher updateBatcher(*this);

  for (uint32_t i = 0; i < aSpecs.Length(); ++i) {
    aSpecs[i]->Unlink();
  }
  aSpecs.Clear();

  RemoveByFunction removeByFunction(aRemove);
  RemoveInstanceTimes(aInstances, removeByFunction);
}

void
nsSMILTimedElement::ClearIntervals()
{
  if (mElementState != STATE_STARTUP) {
    mElementState = STATE_POSTACTIVE;
  }
  mCurrentRepeatIteration = 0;
  ResetCurrentInterval();

  // Remove old intervals
  for (int32_t i = mOldIntervals.Length() - 1; i >= 0; --i) {
    mOldIntervals[i]->Unlink();
  }
  mOldIntervals.Clear();
}

bool
nsSMILTimedElement::ApplyEarlyEnd(const nsSMILTimeValue& aSampleTime)
{
  // This should only be called within DoSampleAt as a helper function
  MOZ_ASSERT(mElementState == STATE_ACTIVE,
             "Unexpected state to try to apply an early end");

  bool updated = false;

  // Only apply an early end if we're not already ending.
  if (mCurrentInterval->End()->Time() > aSampleTime) {
    nsSMILInstanceTime* earlyEnd = CheckForEarlyEnd(aSampleTime);
    if (earlyEnd) {
      if (earlyEnd->IsDependent()) {
        // Generate a new instance time for the early end since the
        // existing instance time is part of some dependency chain that we
        // don't want to participate in.
        RefPtr<nsSMILInstanceTime> newEarlyEnd =
          new nsSMILInstanceTime(earlyEnd->Time());
        mCurrentInterval->SetEnd(*newEarlyEnd);
      } else {
        mCurrentInterval->SetEnd(*earlyEnd);
      }
      updated = true;
    }
  }
  return updated;
}

namespace
{
  class MOZ_STACK_CLASS RemoveReset
  {
  public:
    explicit RemoveReset(const nsSMILInstanceTime* aCurrentIntervalBegin)
      : mCurrentIntervalBegin(aCurrentIntervalBegin) { }
    bool operator()(nsSMILInstanceTime* aInstanceTime, uint32_t /*aIndex*/)
    {
      // SMIL 3.0 section 5.4.3, 'Resetting element state':
      //   Any instance times associated with past Event-values, Repeat-values,
      //   Accesskey-values or added via DOM method calls are removed from the
      //   dependent begin and end instance times lists. In effect, all events
      //   and DOM methods calls in the past are cleared. This does not apply to
      //   an instance time that defines the begin of the current interval.
      return aInstanceTime->IsDynamic() &&
             !aInstanceTime->ShouldPreserve() &&
             (!mCurrentIntervalBegin || aInstanceTime != mCurrentIntervalBegin);
    }

  private:
    const nsSMILInstanceTime* mCurrentIntervalBegin;
  };
} // namespace

void
nsSMILTimedElement::Reset()
{
  RemoveReset resetBegin(mCurrentInterval ? mCurrentInterval->Begin() : nullptr);
  RemoveInstanceTimes(mBeginInstances, resetBegin);

  RemoveReset resetEnd(nullptr);
  RemoveInstanceTimes(mEndInstances, resetEnd);
}

void
nsSMILTimedElement::ClearTimingState(RemovalTestFunction aRemove)
{
  mElementState = STATE_STARTUP;
  ClearIntervals();

  UnsetBeginSpec(aRemove);
  UnsetEndSpec(aRemove);

  if (mClient) {
    mClient->Inactivate(false);
  }
}

void
nsSMILTimedElement::RebuildTimingState(RemovalTestFunction aRemove)
{
  MOZ_ASSERT(mAnimationElement,
             "Attempting to enable a timed element not attached to an "
             "animation element");
  MOZ_ASSERT(mElementState == STATE_STARTUP,
             "Rebuilding timing state from non-startup state");

  if (mAnimationElement->HasAnimAttr(nsGkAtoms::begin)) {
    nsAutoString attValue;
    mAnimationElement->GetAnimAttr(nsGkAtoms::begin, attValue);
    SetBeginSpec(attValue, mAnimationElement, aRemove);
  }

  if (mAnimationElement->HasAnimAttr(nsGkAtoms::end)) {
    nsAutoString attValue;
    mAnimationElement->GetAnimAttr(nsGkAtoms::end, attValue);
    SetEndSpec(attValue, mAnimationElement, aRemove);
  }

  mPrevRegisteredMilestone = sMaxMilestone;
  RegisterMilestone();
}

void
nsSMILTimedElement::DoPostSeek()
{
  // Finish backwards seek
  if (mSeekState == SEEK_BACKWARD_FROM_INACTIVE ||
      mSeekState == SEEK_BACKWARD_FROM_ACTIVE) {
    // Previously some dynamic instance times may have been marked to be
    // preserved because they were endpoints of an historic interval (which may
    // or may not have been filtered). Now that we've finished a seek we should
    // clear that flag for those instance times whose intervals are no longer
    // historic.
    UnpreserveInstanceTimes(mBeginInstances);
    UnpreserveInstanceTimes(mEndInstances);

    // Now that the times have been unmarked perform a reset. This might seem
    // counter-intuitive when we're only doing a seek within an interval but
    // SMIL seems to require this. SMIL 3.0, 'Hyperlinks and timing':
    //   Resolved end times associated with events, Repeat-values,
    //   Accesskey-values or added via DOM method calls are cleared when seeking
    //   to time earlier than the resolved end time.
    Reset();
    UpdateCurrentInterval();
  }

  switch (mSeekState)
  {
  case SEEK_FORWARD_FROM_ACTIVE:
  case SEEK_BACKWARD_FROM_ACTIVE:
    if (mElementState != STATE_ACTIVE) {
      FireTimeEventAsync(eSMILEndEvent, 0);
    }
    break;

  case SEEK_FORWARD_FROM_INACTIVE:
  case SEEK_BACKWARD_FROM_INACTIVE:
    if (mElementState == STATE_ACTIVE) {
      FireTimeEventAsync(eSMILBeginEvent, 0);
    }
    break;

  case SEEK_NOT_SEEKING:
    /* Do nothing */
    break;
  }

  mSeekState = SEEK_NOT_SEEKING;
}

void
nsSMILTimedElement::UnpreserveInstanceTimes(InstanceTimeList& aList)
{
  const nsSMILInterval* prevInterval = GetPreviousInterval();
  const nsSMILInstanceTime* cutoff = mCurrentInterval ?
      mCurrentInterval->Begin() :
      prevInterval ? prevInterval->Begin() : nullptr;
  uint32_t count = aList.Length();
  for (uint32_t i = 0; i < count; ++i) {
    nsSMILInstanceTime* instance = aList[i].get();
    if (!cutoff || cutoff->Time().CompareTo(instance->Time()) < 0) {
      instance->UnmarkShouldPreserve();
    }
  }
}

void
nsSMILTimedElement::FilterHistory()
{
  // We should filter the intervals first, since instance times still used in an
  // interval won't be filtered.
  FilterIntervals();
  FilterInstanceTimes(mBeginInstances);
  FilterInstanceTimes(mEndInstances);
}

void
nsSMILTimedElement::FilterIntervals()
{
  // We can filter old intervals that:
  //
  // a) are not the previous interval; AND
  // b) are not in the middle of a dependency chain; AND
  // c) are not the first interval
  //
  // Condition (a) is necessary since the previous interval is used for applying
  // fill effects and updating the current interval.
  //
  // Condition (b) is necessary since even if this interval itself is not
  // active, it may be part of a dependency chain that includes active
  // intervals. Such chains are used to establish priorities within the
  // animation sandwich.
  //
  // Condition (c) is necessary to support hyperlinks that target animations
  // since in some cases the defined behavior is to seek the document back to
  // the first resolved begin time. Presumably the intention here is not
  // actually to use the first resolved begin time, the
  // _the_first_resolved_begin_time_that_produced_an_interval. That is,
  // if we have begin="-5s; -3s; 1s; 3s" with a duration on 1s, we should seek
  // to 1s. The spec doesn't say this but I'm pretty sure that is the intention.
  // It seems negative times were simply not considered.
  //
  // Although the above conditions allow us to safely filter intervals for most
  // scenarios they do not cover all cases and there will still be scenarios
  // that generate intervals indefinitely. In such a case we simply set
  // a maximum number of intervals and drop any intervals beyond that threshold.

  uint32_t threshold = mOldIntervals.Length() > sMaxNumIntervals ?
                       mOldIntervals.Length() - sMaxNumIntervals :
                       0;
  IntervalList filteredList;
  for (uint32_t i = 0; i < mOldIntervals.Length(); ++i)
  {
    nsSMILInterval* interval = mOldIntervals[i].get();
    if (i != 0 && /*skip first interval*/
        i + 1 < mOldIntervals.Length() && /*skip previous interval*/
        (i < threshold || !interval->IsDependencyChainLink())) {
      interval->Unlink(true /*filtered, not deleted*/);
    } else {
      filteredList.AppendElement(mOldIntervals[i].forget());
    }
  }
  mOldIntervals.Clear();
  mOldIntervals.SwapElements(filteredList);
}

namespace
{
  class MOZ_STACK_CLASS RemoveFiltered
  {
  public:
    explicit RemoveFiltered(nsSMILTimeValue aCutoff) : mCutoff(aCutoff) { }
    bool operator()(nsSMILInstanceTime* aInstanceTime, uint32_t /*aIndex*/)
    {
      // We can filter instance times that:
      // a) Precede the end point of the previous interval; AND
      // b) Are NOT syncbase times that might be updated to a time after the end
      //    point of the previous interval; AND
      // c) Are NOT fixed end points in any remaining interval.
      return aInstanceTime->Time() < mCutoff &&
             aInstanceTime->IsFixedTime() &&
             !aInstanceTime->ShouldPreserve();
    }

  private:
    nsSMILTimeValue mCutoff;
  };

  class MOZ_STACK_CLASS RemoveBelowThreshold
  {
  public:
    RemoveBelowThreshold(uint32_t aThreshold,
                         nsTArray<const nsSMILInstanceTime *>& aTimesToKeep)
      : mThreshold(aThreshold),
        mTimesToKeep(aTimesToKeep) { }
    bool operator()(nsSMILInstanceTime* aInstanceTime, uint32_t aIndex)
    {
      return aIndex < mThreshold && !mTimesToKeep.Contains(aInstanceTime);
    }

  private:
    uint32_t mThreshold;
    nsTArray<const nsSMILInstanceTime *>& mTimesToKeep;
  };
} // namespace

void
nsSMILTimedElement::FilterInstanceTimes(InstanceTimeList& aList)
{
  if (GetPreviousInterval()) {
    RemoveFiltered removeFiltered(GetPreviousInterval()->End()->Time());
    RemoveInstanceTimes(aList, removeFiltered);
  }

  // As with intervals it is possible to create a document that, even despite
  // our most aggressive filtering, will generate instance times indefinitely
  // (e.g. cyclic dependencies with TimeEvents---we can't filter such times as
  // they're unpredictable due to the possibility of seeking the document which
  // may prevent some events from being generated). Therefore we introduce
  // a hard cutoff at which point we just drop the oldest instance times.
  if (aList.Length() > sMaxNumInstanceTimes) {
    uint32_t threshold = aList.Length() - sMaxNumInstanceTimes;
    // There are a few instance times we should keep though, notably:
    // - the current interval begin time,
    // - the previous interval end time (see note in RemoveInstanceTimes)
    // - the first interval begin time (see note in FilterIntervals)
    nsTArray<const nsSMILInstanceTime *> timesToKeep;
    if (mCurrentInterval) {
      timesToKeep.AppendElement(mCurrentInterval->Begin());
    }
    const nsSMILInterval* prevInterval = GetPreviousInterval();
    if (prevInterval) {
      timesToKeep.AppendElement(prevInterval->End());
    }
    if (!mOldIntervals.IsEmpty()) {
      timesToKeep.AppendElement(mOldIntervals[0]->Begin());
    }
    RemoveBelowThreshold removeBelowThreshold(threshold, timesToKeep);
    RemoveInstanceTimes(aList, removeBelowThreshold);
  }
}

//
// This method is based on the pseudocode given in the SMILANIM spec.
//
// See:
// http://www.w3.org/TR/2001/REC-smil-animation-20010904/#Timing-BeginEnd-LC-Start
//
bool
nsSMILTimedElement::GetNextInterval(const nsSMILInterval* aPrevInterval,
                                    const nsSMILInterval* aReplacedInterval,
                                    const nsSMILInstanceTime* aFixedBeginTime,
                                    nsSMILInterval& aResult) const
{
  MOZ_ASSERT(!aFixedBeginTime || aFixedBeginTime->Time().IsDefinite(),
             "Unresolved or indefinite begin time given for interval start");
  static const nsSMILTimeValue zeroTime(0L);

  if (mRestartMode == RESTART_NEVER && aPrevInterval)
    return false;

  // Calc starting point
  nsSMILTimeValue beginAfter;
  bool prevIntervalWasZeroDur = false;
  if (aPrevInterval) {
    beginAfter = aPrevInterval->End()->Time();
    prevIntervalWasZeroDur
      = aPrevInterval->End()->Time() == aPrevInterval->Begin()->Time();
  } else {
    beginAfter.SetMillis(INT64_MIN);
  }

  RefPtr<nsSMILInstanceTime> tempBegin;
  RefPtr<nsSMILInstanceTime> tempEnd;

  while (true) {
    // Calculate begin time
    if (aFixedBeginTime) {
      if (aFixedBeginTime->Time() < beginAfter) {
        return false;
      }
      // our ref-counting is not const-correct
      tempBegin = const_cast<nsSMILInstanceTime*>(aFixedBeginTime);
    } else if ((!mAnimationElement ||
                !mAnimationElement->HasAnimAttr(nsGkAtoms::begin)) &&
               beginAfter <= zeroTime) {
      tempBegin = new nsSMILInstanceTime(nsSMILTimeValue(0));
    } else {
      int32_t beginPos = 0;
      do {
        tempBegin =
          GetNextGreaterOrEqual(mBeginInstances, beginAfter, beginPos);
        if (!tempBegin || !tempBegin->Time().IsDefinite()) {
          return false;
        }
      // If we're updating the current interval then skip any begin time that is
      // dependent on the current interval's begin time. e.g.
      //   <animate id="a" begin="b.begin; a.begin+2s"...
      // If b's interval disappears whilst 'a' is in the waiting state the begin
      // time at "a.begin+2s" should be skipped since 'a' never begun.
      } while (aReplacedInterval &&
               tempBegin->GetBaseTime() == aReplacedInterval->Begin());
    }
    MOZ_ASSERT(tempBegin && tempBegin->Time().IsDefinite() &&
               tempBegin->Time() >= beginAfter,
               "Got a bad begin time while fetching next interval");

    // Calculate end time
    {
      int32_t endPos = 0;
      do {
        tempEnd =
          GetNextGreaterOrEqual(mEndInstances, tempBegin->Time(), endPos);

        // SMIL doesn't allow for coincident zero-duration intervals, so if the
        // previous interval was zero-duration, and tempEnd is going to give us
        // another zero duration interval, then look for another end to use
        // instead.
        if (tempEnd && prevIntervalWasZeroDur &&
            tempEnd->Time() == beginAfter) {
          tempEnd = GetNextGreater(mEndInstances, tempBegin->Time(), endPos);
        }
      // As above with begin times, avoid creating self-referential loops
      // between instance times by checking that the newly found end instance
      // time is not already dependent on the end of the current interval.
      } while (tempEnd && aReplacedInterval &&
               tempEnd->GetBaseTime() == aReplacedInterval->End());

      if (!tempEnd) {
        // If all the ends are before the beginning we have a bad interval
        // UNLESS:
        // a) We never had any end attribute to begin with (the SMIL pseudocode
        //    places this condition earlier in the flow but that fails to allow
        //    for DOM calls when no "indefinite" condition is given), OR
        // b) We never had any end instance times to begin with, OR
        // c) We have end events which leave the interval open-ended.
        bool openEndedIntervalOk = mEndSpecs.IsEmpty() ||
                                   mEndInstances.IsEmpty() ||
                                   EndHasEventConditions();

        // The above conditions correspond with the SMIL pseudocode but SMIL
        // doesn't address self-dependent instance times which we choose to
        // ignore.
        //
        // Therefore we add a qualification of (b) above that even if
        // there are end instance times but they all depend on the end of the
        // current interval we should act as if they didn't exist and allow the
        // open-ended interval.
        //
        // In the following condition we don't use |= because it doesn't provide
        // short-circuit behavior.
        openEndedIntervalOk = openEndedIntervalOk ||
                             (aReplacedInterval &&
                              AreEndTimesDependentOn(aReplacedInterval->End()));

        if (!openEndedIntervalOk) {
          return false; // Bad interval
        }
      }

      nsSMILTimeValue intervalEnd = tempEnd
                                  ? tempEnd->Time() : nsSMILTimeValue();
      nsSMILTimeValue activeEnd = CalcActiveEnd(tempBegin->Time(), intervalEnd);

      if (!tempEnd || intervalEnd != activeEnd) {
        tempEnd = new nsSMILInstanceTime(activeEnd);
      }
    }
    MOZ_ASSERT(tempEnd, "Failed to get end point for next interval");

    // When we choose the interval endpoints, we don't allow coincident
    // zero-duration intervals, so if we arrive here and we have a zero-duration
    // interval starting at the same point as a previous zero-duration interval,
    // then it must be because we've applied constraints to the active duration.
    // In that case, we will potentially run into an infinite loop, so we break
    // it by searching for the next interval that starts AFTER our current
    // zero-duration interval.
    if (prevIntervalWasZeroDur && tempEnd->Time() == beginAfter) {
      if (prevIntervalWasZeroDur) {
        beginAfter.SetMillis(tempBegin->Time().GetMillis() + 1);
        prevIntervalWasZeroDur = false;
        continue;
      }
    }
    prevIntervalWasZeroDur = tempBegin->Time() == tempEnd->Time();

    // Check for valid interval
    if (tempEnd->Time() > zeroTime ||
       (tempBegin->Time() == zeroTime && tempEnd->Time() == zeroTime)) {
      aResult.Set(*tempBegin, *tempEnd);
      return true;
    }

    if (mRestartMode == RESTART_NEVER) {
      // tempEnd <= 0 so we're going to loop which effectively means restarting
      return false;
    }

    beginAfter = tempEnd->Time();
  }
  NS_NOTREACHED("Hmm... we really shouldn't be here");

  return false;
}

nsSMILInstanceTime*
nsSMILTimedElement::GetNextGreater(const InstanceTimeList& aList,
                                   const nsSMILTimeValue& aBase,
                                   int32_t& aPosition) const
{
  nsSMILInstanceTime* result = nullptr;
  while ((result = GetNextGreaterOrEqual(aList, aBase, aPosition)) &&
         result->Time() == aBase) { }
  return result;
}

nsSMILInstanceTime*
nsSMILTimedElement::GetNextGreaterOrEqual(const InstanceTimeList& aList,
                                          const nsSMILTimeValue& aBase,
                                          int32_t& aPosition) const
{
  nsSMILInstanceTime* result = nullptr;
  int32_t count = aList.Length();

  for (; aPosition < count && !result; ++aPosition) {
    nsSMILInstanceTime* val = aList[aPosition].get();
    MOZ_ASSERT(val, "NULL instance time in list");
    if (val->Time() >= aBase) {
      result = val;
    }
  }

  return result;
}

/**
 * @see SMILANIM 3.3.4
 */
nsSMILTimeValue
nsSMILTimedElement::CalcActiveEnd(const nsSMILTimeValue& aBegin,
                                  const nsSMILTimeValue& aEnd) const
{
  nsSMILTimeValue result;

  MOZ_ASSERT(mSimpleDur.IsResolved(),
             "Unresolved simple duration in CalcActiveEnd");
  MOZ_ASSERT(aBegin.IsDefinite(),
             "Indefinite or unresolved begin time in CalcActiveEnd");

  result = GetRepeatDuration();

  if (aEnd.IsDefinite()) {
    nsSMILTime activeDur = aEnd.GetMillis() - aBegin.GetMillis();

    if (result.IsDefinite()) {
      result.SetMillis(std::min(result.GetMillis(), activeDur));
    } else {
      result.SetMillis(activeDur);
    }
  }

  result = ApplyMinAndMax(result);

  if (result.IsDefinite()) {
    nsSMILTime activeEnd = result.GetMillis() + aBegin.GetMillis();
    result.SetMillis(activeEnd);
  }

  return result;
}

nsSMILTimeValue
nsSMILTimedElement::GetRepeatDuration() const
{
  nsSMILTimeValue multipliedDuration;
  if (mRepeatCount.IsDefinite() && mSimpleDur.IsDefinite()) {
    multipliedDuration.SetMillis(
      nsSMILTime(mRepeatCount * double(mSimpleDur.GetMillis())));
  } else {
    multipliedDuration.SetIndefinite();
  }

  nsSMILTimeValue repeatDuration;

  if (mRepeatDur.IsResolved()) {
    repeatDuration = std::min(multipliedDuration, mRepeatDur);
  } else if (mRepeatCount.IsSet()) {
    repeatDuration = multipliedDuration;
  } else {
    repeatDuration = mSimpleDur;
  }

  return repeatDuration;
}

nsSMILTimeValue
nsSMILTimedElement::ApplyMinAndMax(const nsSMILTimeValue& aDuration) const
{
  if (!aDuration.IsResolved()) {
    return aDuration;
  }

  if (mMax < mMin) {
    return aDuration;
  }

  nsSMILTimeValue result;

  if (aDuration > mMax) {
    result = mMax;
  } else if (aDuration < mMin) {
    result = mMin;
  } else {
    result = aDuration;
  }

  return result;
}

nsSMILTime
nsSMILTimedElement::ActiveTimeToSimpleTime(nsSMILTime aActiveTime,
                                           uint32_t& aRepeatIteration)
{
  nsSMILTime result;

  MOZ_ASSERT(mSimpleDur.IsResolved(),
             "Unresolved simple duration in ActiveTimeToSimpleTime");
  MOZ_ASSERT(aActiveTime >= 0, "Expecting non-negative active time");
  // Note that a negative aActiveTime will give us a negative value for
  // aRepeatIteration, which is bad because aRepeatIteration is unsigned

  if (mSimpleDur.IsIndefinite() || mSimpleDur.GetMillis() == 0L) {
    aRepeatIteration = 0;
    result = aActiveTime;
  } else {
    result = aActiveTime % mSimpleDur.GetMillis();
    aRepeatIteration = (uint32_t)(aActiveTime / mSimpleDur.GetMillis());
  }

  return result;
}

//
// Although in many cases it would be possible to check for an early end and
// adjust the current interval well in advance the SMIL Animation spec seems to
// indicate that we should only apply an early end at the latest possible
// moment. In particular, this paragraph from section 3.6.8:
//
// 'If restart  is set to "always", then the current interval will end early if
// there is an instance time in the begin list that is before (i.e. earlier
// than) the defined end for the current interval. Ending in this manner will
// also send a changed time notice to all time dependents for the current
// interval end.'
//
nsSMILInstanceTime*
nsSMILTimedElement::CheckForEarlyEnd(
    const nsSMILTimeValue& aContainerTime) const
{
  MOZ_ASSERT(mCurrentInterval,
             "Checking for an early end but the current interval is not set");
  if (mRestartMode != RESTART_ALWAYS)
    return nullptr;

  int32_t position = 0;
  nsSMILInstanceTime* nextBegin =
    GetNextGreater(mBeginInstances, mCurrentInterval->Begin()->Time(),
                   position);

  if (nextBegin &&
      nextBegin->Time() > mCurrentInterval->Begin()->Time() &&
      nextBegin->Time() < mCurrentInterval->End()->Time() &&
      nextBegin->Time() <= aContainerTime) {
    return nextBegin;
  }

  return nullptr;
}

void
nsSMILTimedElement::UpdateCurrentInterval(bool aForceChangeNotice)
{
  // Check if updates are currently blocked (batched)
  if (mDeferIntervalUpdates) {
    mDoDeferredUpdate = true;
    return;
  }

  // We adopt the convention of not resolving intervals until the first
  // sample. Otherwise, every time each attribute is set we'll re-resolve the
  // current interval and notify all our time dependents of the change.
  //
  // The disadvantage of deferring resolving the interval is that DOM calls to
  // to getStartTime will throw an INVALID_STATE_ERR exception until the
  // document timeline begins since the start time has not yet been resolved.
  if (mElementState == STATE_STARTUP)
    return;

  // Although SMIL gives rules for detecting cycles in change notifications,
  // some configurations can lead to create-delete-create-delete-etc. cycles
  // which SMIL does not consider.
  //
  // In order to provide consistent behavior in such cases, we detect two
  // deletes in a row and then refuse to create any further intervals. That is,
  // we say the configuration is invalid.
  if (mDeleteCount > 1) {
    // When we update the delete count we also set the state to post active, so
    // if we're not post active here then something other than
    // UpdateCurrentInterval has updated the element state in between and all
    // bets are off.
    MOZ_ASSERT(mElementState == STATE_POSTACTIVE,
               "Expected to be in post-active state after performing double "
               "delete");
    return;
  }

  // Check that we aren't stuck in infinite recursion updating some syncbase
  // dependencies. Generally such situations should be detected in advance and
  // the chain broken in a sensible and predictable manner, so if we're hitting
  // this assertion we need to work out how to detect the case that's causing
  // it. In release builds, just bail out before we overflow the stack.
  AutoRestore<uint8_t> depthRestorer(mUpdateIntervalRecursionDepth);
  if (++mUpdateIntervalRecursionDepth > sMaxUpdateIntervalRecursionDepth) {
    MOZ_ASSERT(false,
               "Update current interval recursion depth exceeded threshold");
    return;
  }

  // If the interval is active the begin time is fixed.
  const nsSMILInstanceTime* beginTime = mElementState == STATE_ACTIVE
                                      ? mCurrentInterval->Begin()
                                      : nullptr;
  nsSMILInterval updatedInterval;
  if (GetNextInterval(GetPreviousInterval(), mCurrentInterval,
                      beginTime, updatedInterval)) {

    if (mElementState == STATE_POSTACTIVE) {

      MOZ_ASSERT(!mCurrentInterval,
                 "In postactive state but the interval has been set");
      mCurrentInterval = new nsSMILInterval(updatedInterval);
      mElementState = STATE_WAITING;
      NotifyNewInterval();

    } else {

      bool beginChanged = false;
      bool endChanged   = false;

      if (mElementState != STATE_ACTIVE &&
          !updatedInterval.Begin()->SameTimeAndBase(
            *mCurrentInterval->Begin())) {
        mCurrentInterval->SetBegin(*updatedInterval.Begin());
        beginChanged = true;
      }

      if (!updatedInterval.End()->SameTimeAndBase(*mCurrentInterval->End())) {
        mCurrentInterval->SetEnd(*updatedInterval.End());
        endChanged = true;
      }

      if (beginChanged || endChanged || aForceChangeNotice) {
        NotifyChangedInterval(mCurrentInterval, beginChanged, endChanged);
      }
    }

    // There's a chance our next milestone has now changed, so update the time
    // container
    RegisterMilestone();
  } else { // GetNextInterval failed: Current interval is no longer valid
    if (mElementState == STATE_ACTIVE) {
      // The interval is active so we can't just delete it, instead trim it so
      // that begin==end.
      if (!mCurrentInterval->End()->SameTimeAndBase(*mCurrentInterval->Begin()))
      {
        mCurrentInterval->SetEnd(*mCurrentInterval->Begin());
        NotifyChangedInterval(mCurrentInterval, false, true);
      }
      // The transition to the postactive state will take place on the next
      // sample (along with firing end events, clearing intervals etc.)
      RegisterMilestone();
    } else if (mElementState == STATE_WAITING) {
      AutoRestore<uint8_t> deleteCountRestorer(mDeleteCount);
      ++mDeleteCount;
      mElementState = STATE_POSTACTIVE;
      ResetCurrentInterval();
    }
  }
}

void
nsSMILTimedElement::SampleSimpleTime(nsSMILTime aActiveTime)
{
  if (mClient) {
    uint32_t repeatIteration;
    nsSMILTime simpleTime =
      ActiveTimeToSimpleTime(aActiveTime, repeatIteration);
    mClient->SampleAt(simpleTime, mSimpleDur, repeatIteration);
  }
}

void
nsSMILTimedElement::SampleFillValue()
{
  if (mFillMode != FILL_FREEZE || !mClient)
    return;

  nsSMILTime activeTime;

  if (mElementState == STATE_WAITING || mElementState == STATE_POSTACTIVE) {
    const nsSMILInterval* prevInterval = GetPreviousInterval();
    MOZ_ASSERT(prevInterval,
               "Attempting to sample fill value but there is no previous "
               "interval");
    MOZ_ASSERT(prevInterval->End()->Time().IsDefinite() &&
               prevInterval->End()->IsFixedTime(),
               "Attempting to sample fill value but the endpoint of the "
               "previous interval is not resolved and fixed");

    activeTime = prevInterval->End()->Time().GetMillis() -
                 prevInterval->Begin()->Time().GetMillis();

    // If the interval's repeat duration was shorter than its active duration,
    // use the end of the repeat duration to determine the frozen animation's
    // state.
    nsSMILTimeValue repeatDuration = GetRepeatDuration();
    if (repeatDuration.IsDefinite()) {
      activeTime = std::min(repeatDuration.GetMillis(), activeTime);
    }
  } else {
    MOZ_ASSERT(mElementState == STATE_ACTIVE,
        "Attempting to sample fill value when we're in an unexpected state "
        "(probably STATE_STARTUP)");

    // If we are being asked to sample the fill value while active we *must*
    // have a repeat duration shorter than the active duration so use that.
    MOZ_ASSERT(GetRepeatDuration().IsDefinite(),
        "Attempting to sample fill value of an active animation with "
        "an indefinite repeat duration");
    activeTime = GetRepeatDuration().GetMillis();
  }

  uint32_t repeatIteration;
  nsSMILTime simpleTime =
    ActiveTimeToSimpleTime(activeTime, repeatIteration);

  if (simpleTime == 0L && repeatIteration) {
    mClient->SampleLastValue(--repeatIteration);
  } else {
    mClient->SampleAt(simpleTime, mSimpleDur, repeatIteration);
  }
}

nsresult
nsSMILTimedElement::AddInstanceTimeFromCurrentTime(nsSMILTime aCurrentTime,
    double aOffsetSeconds, bool aIsBegin)
{
  double offset = aOffsetSeconds * PR_MSEC_PER_SEC;

  // Check we won't overflow the range of nsSMILTime
  if (aCurrentTime + NS_round(offset) > INT64_MAX)
    return NS_ERROR_ILLEGAL_VALUE;

  nsSMILTimeValue timeVal(aCurrentTime + int64_t(NS_round(offset)));

  RefPtr<nsSMILInstanceTime> instanceTime =
    new nsSMILInstanceTime(timeVal, nsSMILInstanceTime::SOURCE_DOM);

  AddInstanceTime(instanceTime, aIsBegin);

  return NS_OK;
}

void
nsSMILTimedElement::RegisterMilestone()
{
  nsSMILTimeContainer* container = GetTimeContainer();
  if (!container)
    return;
  MOZ_ASSERT(mAnimationElement,
             "Got a time container without an owning animation element");

  nsSMILMilestone nextMilestone;
  if (!GetNextMilestone(nextMilestone))
    return;

  // This method is called every time we might possibly have updated our
  // current interval, but since nsSMILTimeContainer makes no attempt to filter
  // out redundant milestones we do some rudimentary filtering here. It's not
  // perfect, but unnecessary samples are fairly cheap.
  if (nextMilestone >= mPrevRegisteredMilestone)
    return;

  container->AddMilestone(nextMilestone, *mAnimationElement);
  mPrevRegisteredMilestone = nextMilestone;
}

bool
nsSMILTimedElement::GetNextMilestone(nsSMILMilestone& aNextMilestone) const
{
  // Return the next key moment in our lifetime.
  //
  // XXX It may be possible in future to optimise this so that we only register
  // for milestones if:
  // a) We have time dependents, or
  // b) We are dependent on events or syncbase relationships, or
  // c) There are registered listeners for our events
  //
  // Then for the simple case where everything uses offset values we could
  // ignore milestones altogether.
  //
  // We'd need to be careful, however, that if one of those conditions became
  // true in between samples that we registered our next milestone at that
  // point.

  switch (mElementState)
  {
  case STATE_STARTUP:
    // All elements register for an initial end sample at t=0 where we resolve
    // our initial interval.
    aNextMilestone.mIsEnd = true; // Initial sample should be an end sample
    aNextMilestone.mTime = 0;
    return true;

  case STATE_WAITING:
    MOZ_ASSERT(mCurrentInterval,
               "In waiting state but the current interval has not been set");
    aNextMilestone.mIsEnd = false;
    aNextMilestone.mTime = mCurrentInterval->Begin()->Time().GetMillis();
    return true;

  case STATE_ACTIVE:
    {
      // Work out what comes next: the interval end or the next repeat iteration
      nsSMILTimeValue nextRepeat;
      if (mSeekState == SEEK_NOT_SEEKING && mSimpleDur.IsDefinite()) {
        nsSMILTime nextRepeatActiveTime =
          (mCurrentRepeatIteration + 1) * mSimpleDur.GetMillis();
        // Check that the repeat fits within the repeat duration
        if (nsSMILTimeValue(nextRepeatActiveTime) < GetRepeatDuration()) {
          nextRepeat.SetMillis(mCurrentInterval->Begin()->Time().GetMillis() +
                               nextRepeatActiveTime);
        }
      }
      nsSMILTimeValue nextMilestone =
        std::min(mCurrentInterval->End()->Time(), nextRepeat);

      // Check for an early end before that time
      nsSMILInstanceTime* earlyEnd = CheckForEarlyEnd(nextMilestone);
      if (earlyEnd) {
        aNextMilestone.mIsEnd = true;
        aNextMilestone.mTime = earlyEnd->Time().GetMillis();
        return true;
      }

      // Apply the previously calculated milestone
      if (nextMilestone.IsDefinite()) {
        aNextMilestone.mIsEnd = nextMilestone != nextRepeat;
        aNextMilestone.mTime = nextMilestone.GetMillis();
        return true;
      }

      return false;
    }

  case STATE_POSTACTIVE:
    return false;
  }
  MOZ_CRASH("Invalid element state");
}

void
nsSMILTimedElement::NotifyNewInterval()
{
  MOZ_ASSERT(mCurrentInterval,
             "Attempting to notify dependents of a new interval but the "
             "interval is not set");

  nsSMILTimeContainer* container = GetTimeContainer();
  if (container) {
    container->SyncPauseTime();
  }

  for (auto iter = mTimeDependents.Iter(); !iter.Done(); iter.Next()) {
    nsSMILInterval* interval = mCurrentInterval;
    // It's possible that in notifying one new time dependent of a new interval
    // that a chain reaction is triggered which results in the original
    // interval disappearing. If that's the case we can skip sending further
    // notifications.
    if (!interval) {
      break;
    }
    nsSMILTimeValueSpec* spec = iter.Get()->GetKey();
    spec->HandleNewInterval(*interval, container);
  }
}

void
nsSMILTimedElement::NotifyChangedInterval(nsSMILInterval* aInterval,
                                          bool aBeginObjectChanged,
                                          bool aEndObjectChanged)
{
  MOZ_ASSERT(aInterval, "Null interval for change notification");

  nsSMILTimeContainer* container = GetTimeContainer();
  if (container) {
    container->SyncPauseTime();
  }

  // Copy the instance times list since notifying the instance times can result
  // in a chain reaction whereby our own interval gets deleted along with its
  // instance times.
  InstanceTimeList times;
  aInterval->GetDependentTimes(times);

  for (uint32_t i = 0; i < times.Length(); ++i) {
    times[i]->HandleChangedInterval(container, aBeginObjectChanged,
                                    aEndObjectChanged);
  }
}

void
nsSMILTimedElement::FireTimeEventAsync(EventMessage aMsg, int32_t aDetail)
{
  if (!mAnimationElement)
    return;

  nsCOMPtr<nsIRunnable> event =
    new AsyncTimeEventRunner(mAnimationElement, aMsg, aDetail);
  mAnimationElement->OwnerDoc()->Dispatch(TaskCategory::Other,
                                          event.forget());
}

const nsSMILInstanceTime*
nsSMILTimedElement::GetEffectiveBeginInstance() const
{
  switch (mElementState)
  {
  case STATE_STARTUP:
    return nullptr;

  case STATE_ACTIVE:
    return mCurrentInterval->Begin();

  case STATE_WAITING:
  case STATE_POSTACTIVE:
    {
      const nsSMILInterval* prevInterval = GetPreviousInterval();
      return prevInterval ? prevInterval->Begin() : nullptr;
    }
  }
  MOZ_CRASH("Invalid element state");
}

const nsSMILInterval*
nsSMILTimedElement::GetPreviousInterval() const
{
  return mOldIntervals.IsEmpty()
    ? nullptr
    : mOldIntervals[mOldIntervals.Length()-1].get();
}

bool
nsSMILTimedElement::HasClientInFillRange() const
{
  // Returns true if we have a client that is in the range where it will fill
  return mClient &&
         ((mElementState != STATE_ACTIVE && HasPlayed()) ||
          (mElementState == STATE_ACTIVE && !mClient->IsActive()));
}

bool
nsSMILTimedElement::EndHasEventConditions() const
{
  for (uint32_t i = 0; i < mEndSpecs.Length(); ++i) {
    if (mEndSpecs[i]->IsEventBased())
      return true;
  }
  return false;
}

bool
nsSMILTimedElement::AreEndTimesDependentOn(
  const nsSMILInstanceTime* aBase) const
{
  if (mEndInstances.IsEmpty())
    return false;

  for (uint32_t i = 0; i < mEndInstances.Length(); ++i) {
    if (mEndInstances[i]->GetBaseTime() != aBase) {
      return false;
    }
  }
  return true;
}