content/smil/nsSMILTimeContainer.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "nsSMILTimeContainer.h"
   7 #include "nsSMILTimeValue.h"
   8 #include "nsSMILTimedElement.h"
   9 #include <algorithm>
  10
  11 nsSMILTimeContainer::nsSMILTimeContainer()
  12 :
  13   mParent(nullptr),
  14   mCurrentTime(0L),
  15   mParentOffset(0L),
  16   mPauseStart(0L),
  17   mNeedsPauseSample(false),
  18   mNeedsRewind(false),
  19   mIsSeeking(false),
  20   mPauseState(PAUSE_BEGIN)
  21 {
  22 }
  23
  24 nsSMILTimeContainer::~nsSMILTimeContainer()
  25 {
  26   if (mParent) {
  27     mParent->RemoveChild(*this);
  28   }
  29 }
  30
  31 nsSMILTimeValue
  32 nsSMILTimeContainer::ContainerToParentTime(nsSMILTime aContainerTime) const
  33 {
  34   // If we're paused, then future times are indefinite
  35   if (IsPaused() && aContainerTime > mCurrentTime)
  36     return nsSMILTimeValue::Indefinite();
  37
  38   return nsSMILTimeValue(aContainerTime + mParentOffset);
  39 }
  40
  41 nsSMILTimeValue
  42 nsSMILTimeContainer::ParentToContainerTime(nsSMILTime aParentTime) const
  43 {
  44   // If we're paused, then any time after when we paused is indefinite
  45   if (IsPaused() && aParentTime > mPauseStart)
  46     return nsSMILTimeValue::Indefinite();
  47
  48   return nsSMILTimeValue(aParentTime - mParentOffset);
  49 }
  50
  51 void
  52 nsSMILTimeContainer::Begin()
  53 {
  54   Resume(PAUSE_BEGIN);
  55   if (mPauseState) {
  56     mNeedsPauseSample = true;
  57   }
  58
  59   // This is a little bit complicated here. Ideally we'd just like to call
  60   // Sample() and force an initial sample but this turns out to be a bad idea
  61   // because this may mean that NeedsSample() no longer reports true and so when
  62   // we come to the first real sample our parent will skip us over altogether.
  63   // So we force the time to be updated and adopt the policy to never call
  64   // Sample() ourselves but to always leave that to our parent or client.
  65
  66   UpdateCurrentTime();
  67 }
  68
  69 void
  70 nsSMILTimeContainer::Pause(uint32_t aType)
  71 {
  72   bool didStartPause = false;
  73
  74   if (!mPauseState && aType) {
  75     mPauseStart = GetParentTime();
  76     mNeedsPauseSample = true;
  77     didStartPause = true;
  78   }
  79
  80   mPauseState |= aType;
  81
  82   if (didStartPause) {
  83     NotifyTimeChange();
  84   }
  85 }
  86
  87 void
  88 nsSMILTimeContainer::Resume(uint32_t aType)
  89 {
  90   if (!mPauseState)
  91     return;
  92
  93   mPauseState &= ~aType;
  94
  95   if (!mPauseState) {
  96     nsSMILTime extraOffset = GetParentTime() - mPauseStart;
  97     mParentOffset += extraOffset;
  98     NotifyTimeChange();
  99   }
 100 }
 101
 102 nsSMILTime
 103 nsSMILTimeContainer::GetCurrentTime() const
 104 {
 105   // The following behaviour is consistent with:
 106   // http://www.w3.org/2003/01/REC-SVG11-20030114-errata
 107   //  #getCurrentTime_setCurrentTime_undefined_before_document_timeline_begin
 108   // which says that if GetCurrentTime is called before the document timeline
 109   // has begun we should just return 0.
 110   if (IsPausedByType(PAUSE_BEGIN))
 111     return 0L;
 112
 113   return mCurrentTime;
 114 }
 115
 116 void
 117 nsSMILTimeContainer::SetCurrentTime(nsSMILTime aSeekTo)
 118 {
 119   // SVG 1.1 doesn't specify what to do for negative times so we adopt SVGT1.2's
 120   // behaviour of clamping negative times to 0.
 121   aSeekTo = std::max<nsSMILTime>(0, aSeekTo);
 122
 123   // The following behaviour is consistent with:
 124   // http://www.w3.org/2003/01/REC-SVG11-20030114-errata
 125   //  #getCurrentTime_setCurrentTime_undefined_before_document_timeline_begin
 126   // which says that if SetCurrentTime is called before the document timeline
 127   // has begun we should still adjust the offset.
 128   nsSMILTime parentTime = GetParentTime();
 129   mParentOffset = parentTime - aSeekTo;
 130   mIsSeeking = true;
 131
 132   if (IsPaused()) {
 133     mNeedsPauseSample = true;
 134     mPauseStart = parentTime;
 135   }
 136
 137   if (aSeekTo < mCurrentTime) {
 138     // Backwards seek
 139     mNeedsRewind = true;
 140     ClearMilestones();
 141   }
 142
 143   // Force an update to the current time in case we get a call to GetCurrentTime
 144   // before another call to Sample().
 145   UpdateCurrentTime();
 146
 147   NotifyTimeChange();
 148 }
 149
 150 nsSMILTime
 151 nsSMILTimeContainer::GetParentTime() const
 152 {
 153   if (mParent)
 154     return mParent->GetCurrentTime();
 155
 156   return 0L;
 157 }
 158
 159 void
 160 nsSMILTimeContainer::SyncPauseTime()
 161 {
 162   if (IsPaused()) {
 163     nsSMILTime parentTime = GetParentTime();
 164     nsSMILTime extraOffset = parentTime - mPauseStart;
 165     mParentOffset += extraOffset;
 166     mPauseStart = parentTime;
 167   }
 168 }
 169
 170 void
 171 nsSMILTimeContainer::Sample()
 172 {
 173   if (!NeedsSample())
 174     return;
 175
 176   UpdateCurrentTime();
 177   DoSample();
 178
 179   mNeedsPauseSample = false;
 180 }
 181
 182 nsresult
 183 nsSMILTimeContainer::SetParent(nsSMILTimeContainer* aParent)
 184 {
 185   if (mParent) {
 186     mParent->RemoveChild(*this);
 187     // When we're not attached to a parent time container, GetParentTime() will
 188     // return 0. We need to adjust our pause state information to be relative to
 189     // this new time base.
 190     // Note that since "current time = parent time - parent offset" setting the
 191     // parent offset and pause start as follows preserves our current time even
 192     // while parent time = 0.
 193     mParentOffset = -mCurrentTime;
 194     mPauseStart = 0L;
 195   }
 196
 197   mParent = aParent;
 198
 199   nsresult rv = NS_OK;
 200   if (mParent) {
 201     rv = mParent->AddChild(*this);
 202   }
 203
 204   return rv;
 205 }
 206
 207 bool
 208 nsSMILTimeContainer::AddMilestone(const nsSMILMilestone& aMilestone,
 209                                   mozilla::dom::SVGAnimationElement& aElement)
 210 {
 211   // We record the milestone time and store it along with the element but this
 212   // time may change (e.g. if attributes are changed on the timed element in
 213   // between samples). If this happens, then we may do an unecessary sample
 214   // but that's pretty cheap.
 215   return mMilestoneEntries.Push(MilestoneEntry(aMilestone, aElement));
 216 }
 217
 218 void
 219 nsSMILTimeContainer::ClearMilestones()
 220 {
 221   mMilestoneEntries.Clear();
 222 }
 223
 224 bool
 225 nsSMILTimeContainer::GetNextMilestoneInParentTime(
 226     nsSMILMilestone& aNextMilestone) const
 227 {
 228   if (mMilestoneEntries.IsEmpty())
 229     return false;
 230
 231   nsSMILTimeValue parentTime =
 232     ContainerToParentTime(mMilestoneEntries.Top().mMilestone.mTime);
 233   if (!parentTime.IsDefinite())
 234     return false;
 235
 236   aNextMilestone = nsSMILMilestone(parentTime.GetMillis(),
 237                                    mMilestoneEntries.Top().mMilestone.mIsEnd);
 238
 239   return true;
 240 }
 241
 242 bool
 243 nsSMILTimeContainer::PopMilestoneElementsAtMilestone(
 244       const nsSMILMilestone& aMilestone,
 245       AnimElemArray& aMatchedElements)
 246 {
 247   if (mMilestoneEntries.IsEmpty())
 248     return false;
 249
 250   nsSMILTimeValue containerTime = ParentToContainerTime(aMilestone.mTime);
 251   if (!containerTime.IsDefinite())
 252     return false;
 253
 254   nsSMILMilestone containerMilestone(containerTime.GetMillis(),
 255                                      aMilestone.mIsEnd);
 256
 257   NS_ABORT_IF_FALSE(mMilestoneEntries.Top().mMilestone >= containerMilestone,
 258       "Trying to pop off earliest times but we have earlier ones that were "
 259       "overlooked");
 260
 261   bool gotOne = false;
 262   while (!mMilestoneEntries.IsEmpty() &&
 263       mMilestoneEntries.Top().mMilestone == containerMilestone)
 264   {
 265     aMatchedElements.AppendElement(mMilestoneEntries.Pop().mTimebase);
 266     gotOne = true;
 267   }
 268
 269   return gotOne;
 270 }
 271
 272 void
 273 nsSMILTimeContainer::Traverse(nsCycleCollectionTraversalCallback* aCallback)
 274 {
 275   const MilestoneEntry* p = mMilestoneEntries.Elements();
 276   while (p < mMilestoneEntries.Elements() + mMilestoneEntries.Length()) {
 277     NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCallback, "mTimebase");
 278     aCallback->NoteXPCOMChild(static_cast<nsIContent*>(p->mTimebase.get()));
 279     ++p;
 280   }
 281 }
 282
 283 void
 284 nsSMILTimeContainer::Unlink()
 285 {
 286   mMilestoneEntries.Clear();
 287 }
 288
 289 void
 290 nsSMILTimeContainer::UpdateCurrentTime()
 291 {
 292   nsSMILTime now = IsPaused() ? mPauseStart : GetParentTime();
 293   mCurrentTime = now - mParentOffset;
 294   NS_ABORT_IF_FALSE(mCurrentTime >= 0, "Container has negative time");
 295 }
 296
 297 void
 298 nsSMILTimeContainer::NotifyTimeChange()
 299 {
 300   // Called when the container time is changed with respect to the document
 301   // time. When this happens time dependencies in other time containers need to
 302   // re-resolve their times because begin and end times are stored in container
 303   // time.
 304   //
 305   // To get the list of timed elements with dependencies we simply re-use the
 306   // milestone elements. This is because any timed element with dependents and
 307   // with significant transitions yet to fire should have their next milestone
 308   // registered. Other timed elements don't matter.
 309   const MilestoneEntry* p = mMilestoneEntries.Elements();
 310 #if DEBUG
 311   uint32_t queueLength = mMilestoneEntries.Length();
 312 #endif
 313   while (p < mMilestoneEntries.Elements() + mMilestoneEntries.Length()) {
 314     mozilla::dom::SVGAnimationElement* elem = p->mTimebase.get();
 315     elem->TimedElement().HandleContainerTimeChange();
 316     NS_ABORT_IF_FALSE(queueLength == mMilestoneEntries.Length(),
 317         "Call to HandleContainerTimeChange resulted in a change to the "
 318         "queue of milestones");
 319     ++p;
 320   }
 321 }