1 files changed, 306 insertions, 0 deletions
diff --git a/dom/smil/SMILTimeContainer.cpp b/dom/smil/SMILTimeContainer.cpp
new file mode 100644
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+++ b/dom/smil/SMILTimeContainer.cpp
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+/* -*- 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 "SMILTimeContainer.h"
+
+#include "mozilla/AutoRestore.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/SMILTimedElement.h"
+#include "mozilla/SMILTimeValue.h"
+#include <algorithm>
+
+namespace mozilla {
+
+SMILTimeContainer::SMILTimeContainer()
+    : mParent(nullptr),
+      mCurrentTime(0L),
+      mParentOffset(0L),
+      mPauseStart(0L),
+      mNeedsPauseSample(false),
+      mNeedsRewind(false),
+      mIsSeeking(false),
+#ifdef DEBUG
+      mHoldingEntries(false),
+#endif
+      mPauseState(PAUSE_BEGIN) {
+}
+
+SMILTimeContainer::~SMILTimeContainer() {
+  if (mParent) {
+    mParent->RemoveChild(*this);
+  }
+}
+
+SMILTimeValue SMILTimeContainer::ContainerToParentTime(
+    SMILTime aContainerTime) const {
+  // If we're paused, then future times are indefinite
+  if (IsPaused() && aContainerTime > mCurrentTime)
+    return SMILTimeValue::Indefinite();
+
+  return SMILTimeValue(aContainerTime + mParentOffset);
+}
+
+SMILTimeValue SMILTimeContainer::ParentToContainerTime(
+    SMILTime aParentTime) const {
+  // If we're paused, then any time after when we paused is indefinite
+  if (IsPaused() && aParentTime > mPauseStart)
+    return SMILTimeValue::Indefinite();
+
+  return SMILTimeValue(aParentTime - mParentOffset);
+}
+
+void SMILTimeContainer::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 SMILTimeContainer::Pause(uint32_t aType) {
+  bool didStartPause = false;
+
+  if (!mPauseState && aType) {
+    mPauseStart = GetParentTime();
+    mNeedsPauseSample = true;
+    didStartPause = true;
+  }
+
+  mPauseState |= aType;
+
+  if (didStartPause) {
+    NotifyTimeChange();
+  }
+}
+
+void SMILTimeContainer::Resume(uint32_t aType) {
+  if (!mPauseState) return;
+
+  mPauseState &= ~aType;
+
+  if (!mPauseState) {
+    SMILTime extraOffset = GetParentTime() - mPauseStart;
+    mParentOffset += extraOffset;
+    NotifyTimeChange();
+  }
+}
+
+SMILTime SMILTimeContainer::GetCurrentTimeAsSMILTime() 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 SMILTimeContainer::SetCurrentTime(SMILTime 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<SMILTime>(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.
+  SMILTime 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();
+}
+
+SMILTime SMILTimeContainer::GetParentTime() const {
+  if (mParent) return mParent->GetCurrentTimeAsSMILTime();
+
+  return 0L;
+}
+
+void SMILTimeContainer::SyncPauseTime() {
+  if (IsPaused()) {
+    SMILTime parentTime = GetParentTime();
+    SMILTime extraOffset = parentTime - mPauseStart;
+    mParentOffset += extraOffset;
+    mPauseStart = parentTime;
+  }
+}
+
+void SMILTimeContainer::Sample() {
+  if (!NeedsSample()) return;
+
+  UpdateCurrentTime();
+  DoSample();
+
+  mNeedsPauseSample = false;
+}
+
+nsresult SMILTimeContainer::SetParent(SMILTimeContainer* 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;
+}
+
+void SMILTimeContainer::AddMilestone(
+    const SMILMilestone& 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.
+  MOZ_ASSERT(!mHoldingEntries);
+  mMilestoneEntries.Push(MilestoneEntry(aMilestone, aElement));
+}
+
+void SMILTimeContainer::ClearMilestones() {
+  MOZ_ASSERT(!mHoldingEntries);
+  mMilestoneEntries.Clear();
+}
+
+bool SMILTimeContainer::GetNextMilestoneInParentTime(
+    SMILMilestone& aNextMilestone) const {
+  if (mMilestoneEntries.IsEmpty()) return false;
+
+  SMILTimeValue parentTime =
+      ContainerToParentTime(mMilestoneEntries.Top().mMilestone.mTime);
+  if (!parentTime.IsDefinite()) return false;
+
+  aNextMilestone = SMILMilestone(parentTime.GetMillis(),
+                                 mMilestoneEntries.Top().mMilestone.mIsEnd);
+
+  return true;
+}
+
+bool SMILTimeContainer::PopMilestoneElementsAtMilestone(
+    const SMILMilestone& aMilestone, AnimElemArray& aMatchedElements) {
+  if (mMilestoneEntries.IsEmpty()) return false;
+
+  SMILTimeValue containerTime = ParentToContainerTime(aMilestone.mTime);
+  if (!containerTime.IsDefinite()) return false;
+
+  SMILMilestone containerMilestone(containerTime.GetMillis(),
+                                   aMilestone.mIsEnd);
+
+  MOZ_ASSERT(mMilestoneEntries.Top().mMilestone >= containerMilestone,
+             "Trying to pop off earliest times but we have earlier ones that "
+             "were overlooked");
+
+  MOZ_ASSERT(!mHoldingEntries);
+
+  bool gotOne = false;
+  while (!mMilestoneEntries.IsEmpty() &&
+         mMilestoneEntries.Top().mMilestone == containerMilestone) {
+    aMatchedElements.AppendElement(mMilestoneEntries.Pop().mTimebase);
+    gotOne = true;
+  }
+
+  return gotOne;
+}
+
+void SMILTimeContainer::Traverse(
+    nsCycleCollectionTraversalCallback* aCallback) {
+#ifdef DEBUG
+  AutoRestore<bool> saveHolding(mHoldingEntries);
+  mHoldingEntries = true;
+#endif
+  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 SMILTimeContainer::Unlink() {
+  MOZ_ASSERT(!mHoldingEntries);
+  mMilestoneEntries.Clear();
+}
+
+void SMILTimeContainer::UpdateCurrentTime() {
+  SMILTime now = IsPaused() ? mPauseStart : GetParentTime();
+  MOZ_ASSERT(now >= mParentOffset,
+             "Container has negative time with respect to parent");
+  const auto updatedCurrentTime = CheckedInt<SMILTime>(now) - mParentOffset;
+  mCurrentTime = updatedCurrentTime.isValid()
+                     ? updatedCurrentTime.value()
+                     : std::numeric_limits<SMILTime>::max();
+}
+
+void SMILTimeContainer::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.
+
+  // Copy the timed elements to a separate array before calling
+  // HandleContainerTimeChange on each of them in case doing so mutates
+  // mMilestoneEntries.
+  nsTArray<RefPtr<mozilla::dom::SVGAnimationElement>> elems;
+
+  {
+#ifdef DEBUG
+    AutoRestore<bool> saveHolding(mHoldingEntries);
+    mHoldingEntries = true;
+#endif
+    for (const MilestoneEntry* p = mMilestoneEntries.Elements();
+         p < mMilestoneEntries.Elements() + mMilestoneEntries.Length(); ++p) {
+      elems.AppendElement(p->mTimebase.get());
+    }
+  }
+
+  for (auto& elem : elems) {
+    elem->TimedElement().HandleContainerTimeChange();
+  }
+}
+
+}  // namespace mozilla