dom/smil/nsSMILTimeContainer.cpp
author Ryan VanderMeulen <ryanvm@gmail.com>
Thu, 10 Jul 2014 21:43:04 -0400
changeset 215438 70f3b01cb736ea9f21d692e537058ad3859a9c69
parent 179347 215f5bc6284dfc1778d01ae0fe52a9ea96d6bf2a
child 256528 7fa65aa297a48f9f568e58e38534f1c028624d64
permissions -rw-r--r--
Backed out 5 changesets (bug 1020760, bug 1035653, bug 1020090) for leaks on a CLOSED TREE. Backed out changeset f0b20e3db93c (bug 1020760) Backed out changeset 412b654e5cd2 (bug 1035653) Backed out changeset 01ba0892af29 (bug 1020760) Backed out changeset c7de1f4b078f (bug 1020760) Backed out changeset 96aa9d33a1f5 (bug 1020090)

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "nsSMILTimeContainer.h"
#include "nsSMILTimeValue.h"
#include "nsSMILTimedElement.h"
#include <algorithm>

nsSMILTimeContainer::nsSMILTimeContainer()
:
  mParent(nullptr),
  mCurrentTime(0L),
  mParentOffset(0L),
  mPauseStart(0L),
  mNeedsPauseSample(false),
  mNeedsRewind(false),
  mIsSeeking(false),
  mPauseState(PAUSE_BEGIN)
{
}

nsSMILTimeContainer::~nsSMILTimeContainer()
{
  if (mParent) {
    mParent->RemoveChild(*this);
  }
}

nsSMILTimeValue
nsSMILTimeContainer::ContainerToParentTime(nsSMILTime aContainerTime) const
{
  // If we're paused, then future times are indefinite
  if (IsPaused() && aContainerTime > mCurrentTime)
    return nsSMILTimeValue::Indefinite();

  return nsSMILTimeValue(aContainerTime + mParentOffset);
}

nsSMILTimeValue
nsSMILTimeContainer::ParentToContainerTime(nsSMILTime aParentTime) const
{
  // If we're paused, then any time after when we paused is indefinite
  if (IsPaused() && aParentTime > mPauseStart)
    return nsSMILTimeValue::Indefinite();

  return nsSMILTimeValue(aParentTime - mParentOffset);
}

void
nsSMILTimeContainer::Begin()
{
  Resume(PAUSE_BEGIN);
  if (mPauseState) {
    mNeedsPauseSample = true;
  }

  // This is a little bit complicated here. Ideally we'd just like to call
  // Sample() and force an initial sample but this turns out to be a bad idea
  // because this may mean that NeedsSample() no longer reports true and so when
  // we come to the first real sample our parent will skip us over altogether.
  // So we force the time to be updated and adopt the policy to never call
  // Sample() ourselves but to always leave that to our parent or client.

  UpdateCurrentTime();
}

void
nsSMILTimeContainer::Pause(uint32_t aType)
{
  bool didStartPause = false;

  if (!mPauseState && aType) {
    mPauseStart = GetParentTime();
    mNeedsPauseSample = true;
    didStartPause = true;
  }

  mPauseState |= aType;

  if (didStartPause) {
    NotifyTimeChange();
  }
}

void
nsSMILTimeContainer::Resume(uint32_t aType)
{
  if (!mPauseState)
    return;

  mPauseState &= ~aType;

  if (!mPauseState) {
    nsSMILTime extraOffset = GetParentTime() - mPauseStart;
    mParentOffset += extraOffset;
    NotifyTimeChange();
  }
}

nsSMILTime
nsSMILTimeContainer::GetCurrentTime() const
{
  // The following behaviour is consistent with:
  // http://www.w3.org/2003/01/REC-SVG11-20030114-errata
  //  #getCurrentTime_setCurrentTime_undefined_before_document_timeline_begin
  // which says that if GetCurrentTime is called before the document timeline
  // has begun we should just return 0.
  if (IsPausedByType(PAUSE_BEGIN))
    return 0L;

  return mCurrentTime;
}

void
nsSMILTimeContainer::SetCurrentTime(nsSMILTime aSeekTo)
{
  // SVG 1.1 doesn't specify what to do for negative times so we adopt SVGT1.2's
  // behaviour of clamping negative times to 0.
  aSeekTo = std::max<nsSMILTime>(0, aSeekTo);

  // The following behaviour is consistent with:
  // http://www.w3.org/2003/01/REC-SVG11-20030114-errata
  //  #getCurrentTime_setCurrentTime_undefined_before_document_timeline_begin
  // which says that if SetCurrentTime is called before the document timeline
  // has begun we should still adjust the offset.
  nsSMILTime parentTime = GetParentTime();
  mParentOffset = parentTime - aSeekTo;
  mIsSeeking = true;

  if (IsPaused()) {
    mNeedsPauseSample = true;
    mPauseStart = parentTime;
  }

  if (aSeekTo < mCurrentTime) {
    // Backwards seek
    mNeedsRewind = true;
    ClearMilestones();
  }

  // Force an update to the current time in case we get a call to GetCurrentTime
  // before another call to Sample().
  UpdateCurrentTime();

  NotifyTimeChange();
}

nsSMILTime
nsSMILTimeContainer::GetParentTime() const
{
  if (mParent)
    return mParent->GetCurrentTime();

  return 0L;
}

void
nsSMILTimeContainer::SyncPauseTime()
{
  if (IsPaused()) {
    nsSMILTime parentTime = GetParentTime();
    nsSMILTime extraOffset = parentTime - mPauseStart;
    mParentOffset += extraOffset;
    mPauseStart = parentTime;
  }
}

void
nsSMILTimeContainer::Sample()
{
  if (!NeedsSample())
    return;

  UpdateCurrentTime();
  DoSample();

  mNeedsPauseSample = false;
}

nsresult
nsSMILTimeContainer::SetParent(nsSMILTimeContainer* aParent)
{
  if (mParent) {
    mParent->RemoveChild(*this);
    // When we're not attached to a parent time container, GetParentTime() will
    // return 0. We need to adjust our pause state information to be relative to
    // this new time base.
    // Note that since "current time = parent time - parent offset" setting the
    // parent offset and pause start as follows preserves our current time even
    // while parent time = 0.
    mParentOffset = -mCurrentTime;
    mPauseStart = 0L;
  }

  mParent = aParent;

  nsresult rv = NS_OK;
  if (mParent) {
    rv = mParent->AddChild(*this);
  }

  return rv;
}

bool
nsSMILTimeContainer::AddMilestone(const nsSMILMilestone& aMilestone,
                                  mozilla::dom::SVGAnimationElement& aElement)
{
  // We record the milestone time and store it along with the element but this
  // time may change (e.g. if attributes are changed on the timed element in
  // between samples). If this happens, then we may do an unecessary sample
  // but that's pretty cheap.
  return mMilestoneEntries.Push(MilestoneEntry(aMilestone, aElement));
}

void
nsSMILTimeContainer::ClearMilestones()
{
  mMilestoneEntries.Clear();
}

bool
nsSMILTimeContainer::GetNextMilestoneInParentTime(
    nsSMILMilestone& aNextMilestone) const
{
  if (mMilestoneEntries.IsEmpty())
    return false;

  nsSMILTimeValue parentTime =
    ContainerToParentTime(mMilestoneEntries.Top().mMilestone.mTime);
  if (!parentTime.IsDefinite())
    return false;

  aNextMilestone = nsSMILMilestone(parentTime.GetMillis(),
                                   mMilestoneEntries.Top().mMilestone.mIsEnd);

  return true;
}

bool
nsSMILTimeContainer::PopMilestoneElementsAtMilestone(
      const nsSMILMilestone& aMilestone,
      AnimElemArray& aMatchedElements)
{
  if (mMilestoneEntries.IsEmpty())
    return false;

  nsSMILTimeValue containerTime = ParentToContainerTime(aMilestone.mTime);
  if (!containerTime.IsDefinite())
    return false;

  nsSMILMilestone containerMilestone(containerTime.GetMillis(),
                                     aMilestone.mIsEnd);

  NS_ABORT_IF_FALSE(mMilestoneEntries.Top().mMilestone >= containerMilestone,
      "Trying to pop off earliest times but we have earlier ones that were "
      "overlooked");

  bool gotOne = false;
  while (!mMilestoneEntries.IsEmpty() &&
      mMilestoneEntries.Top().mMilestone == containerMilestone)
  {
    aMatchedElements.AppendElement(mMilestoneEntries.Pop().mTimebase);
    gotOne = true;
  }

  return gotOne;
}

void
nsSMILTimeContainer::Traverse(nsCycleCollectionTraversalCallback* aCallback)
{
  const MilestoneEntry* p = mMilestoneEntries.Elements();
  while (p < mMilestoneEntries.Elements() + mMilestoneEntries.Length()) {
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCallback, "mTimebase");
    aCallback->NoteXPCOMChild(static_cast<nsIContent*>(p->mTimebase.get()));
    ++p;
  }
}

void
nsSMILTimeContainer::Unlink()
{
  mMilestoneEntries.Clear();
}

void
nsSMILTimeContainer::UpdateCurrentTime()
{
  nsSMILTime now = IsPaused() ? mPauseStart : GetParentTime();
  mCurrentTime = now - mParentOffset;
  NS_ABORT_IF_FALSE(mCurrentTime >= 0, "Container has negative time");
}

void
nsSMILTimeContainer::NotifyTimeChange()
{
  // Called when the container time is changed with respect to the document
  // time. When this happens time dependencies in other time containers need to
  // re-resolve their times because begin and end times are stored in container
  // time.
  //
  // To get the list of timed elements with dependencies we simply re-use the
  // milestone elements. This is because any timed element with dependents and
  // with significant transitions yet to fire should have their next milestone
  // registered. Other timed elements don't matter.
  const MilestoneEntry* p = mMilestoneEntries.Elements();
#if DEBUG
  uint32_t queueLength = mMilestoneEntries.Length();
#endif
  while (p < mMilestoneEntries.Elements() + mMilestoneEntries.Length()) {
    mozilla::dom::SVGAnimationElement* elem = p->mTimebase.get();
    elem->TimedElement().HandleContainerTimeChange();
    NS_ABORT_IF_FALSE(queueLength == mMilestoneEntries.Length(),
        "Call to HandleContainerTimeChange resulted in a change to the "
        "queue of milestones");
    ++p;
  }
}