1 files changed, 519 insertions, 0 deletions
diff --git a/image/FrameAnimator.cpp b/image/FrameAnimator.cpp
new file mode 100644
index 0000000000..f21877d81a
--- /dev/null
+++ b/image/FrameAnimator.cpp
@@ -0,0 +1,519 @@
+/* -*- 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 "FrameAnimator.h"
+
+#include <utility>
+
+#include "LookupResult.h"
+#include "RasterImage.h"
+#include "imgIContainer.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/StaticPrefs_image.h"
+
+namespace mozilla {
+
+using namespace gfx;
+
+namespace image {
+
+///////////////////////////////////////////////////////////////////////////////
+// AnimationState implementation.
+///////////////////////////////////////////////////////////////////////////////
+
+const gfx::IntRect AnimationState::UpdateState(
+    RasterImage* aImage, const gfx::IntSize& aSize,
+    bool aAllowInvalidation /* = true */) {
+  LookupResult result = SurfaceCache::Lookup(
+      ImageKey(aImage),
+      RasterSurfaceKey(aSize, DefaultSurfaceFlags(), PlaybackType::eAnimated),
+      /* aMarkUsed = */ false);
+
+  return UpdateStateInternal(result, aSize, aAllowInvalidation);
+}
+
+const gfx::IntRect AnimationState::UpdateStateInternal(
+    LookupResult& aResult, const gfx::IntSize& aSize,
+    bool aAllowInvalidation /* = true */) {
+  // Update mDiscarded and mIsCurrentlyDecoded.
+  if (aResult.Type() == MatchType::NOT_FOUND) {
+    // no frames, we've either been discarded, or never been decoded before.
+    mDiscarded = mHasBeenDecoded;
+    mIsCurrentlyDecoded = false;
+  } else if (aResult.Type() == MatchType::PENDING) {
+    // no frames yet, but a decoder is or will be working on it.
+    mDiscarded = false;
+    mIsCurrentlyDecoded = false;
+    mHasRequestedDecode = true;
+  } else {
+    MOZ_ASSERT(aResult.Type() == MatchType::EXACT);
+    mDiscarded = false;
+    mHasRequestedDecode = true;
+
+    // If we can seek to the current animation frame we consider it decoded.
+    // Animated images are never fully decoded unless very short.
+    // Note that we use GetFrame instead of Seek here. The difference is that
+    // Seek eventually calls AnimationFrameBuffer::Get with aForDisplay == true,
+    // whereas GetFrame calls AnimationFrameBuffer::Get with aForDisplay ==
+    // false. The aForDisplay can change whether those functions succeed or not
+    // (only for the first frame). Since this is not for display we want to pass
+    // aForDisplay == false, but also for consistency with
+    // RequestRefresh/AdvanceFrame, because we want our state to be in sync with
+    // those functions. The user of Seek (GetCompositedFrame) doesn't need to be
+    // in sync with our state.
+    RefPtr<imgFrame> currentFrame =
+        bool(aResult.Surface())
+            ? aResult.Surface().GetFrame(mCurrentAnimationFrameIndex)
+            : nullptr;
+    mIsCurrentlyDecoded = !!currentFrame;
+  }
+
+  gfx::IntRect ret;
+
+  if (aAllowInvalidation) {
+    // Update the value of mCompositedFrameInvalid.
+    if (mIsCurrentlyDecoded) {
+      // It is safe to clear mCompositedFrameInvalid safe to do for images that
+      // are fully decoded but aren't finished animating because before we paint
+      // the refresh driver will call into us to advance to the correct frame,
+      // and that will succeed because we have all the frames.
+      if (mCompositedFrameInvalid) {
+        // Invalidate if we are marking the composited frame valid.
+        ret.SizeTo(aSize);
+      }
+      mCompositedFrameInvalid = false;
+    } else {
+      if (mHasRequestedDecode) {
+        MOZ_ASSERT(StaticPrefs::image_mem_animated_discardable_AtStartup());
+        mCompositedFrameInvalid = true;
+      }
+    }
+    // Otherwise don't change the value of mCompositedFrameInvalid, it will be
+    // updated by RequestRefresh.
+  }
+
+  return ret;
+}
+
+void AnimationState::NotifyDecodeComplete() { mHasBeenDecoded = true; }
+
+void AnimationState::ResetAnimation() { mCurrentAnimationFrameIndex = 0; }
+
+void AnimationState::SetAnimationMode(uint16_t aAnimationMode) {
+  mAnimationMode = aAnimationMode;
+}
+
+void AnimationState::UpdateKnownFrameCount(uint32_t aFrameCount) {
+  if (aFrameCount <= mFrameCount) {
+    // Nothing to do. Since we can redecode animated images, we may see the same
+    // sequence of updates replayed again, so seeing a smaller frame count than
+    // what we already know about doesn't indicate an error.
+    return;
+  }
+
+  MOZ_ASSERT(!mHasBeenDecoded, "Adding new frames after decoding is finished?");
+  MOZ_ASSERT(aFrameCount <= mFrameCount + 1, "Skipped a frame?");
+
+  mFrameCount = aFrameCount;
+}
+
+Maybe<uint32_t> AnimationState::FrameCount() const {
+  return mHasBeenDecoded ? Some(mFrameCount) : Nothing();
+}
+
+void AnimationState::SetFirstFrameRefreshArea(const IntRect& aRefreshArea) {
+  mFirstFrameRefreshArea = aRefreshArea;
+}
+
+void AnimationState::InitAnimationFrameTimeIfNecessary() {
+  if (mCurrentAnimationFrameTime.IsNull()) {
+    mCurrentAnimationFrameTime = TimeStamp::Now();
+  }
+}
+
+void AnimationState::SetAnimationFrameTime(const TimeStamp& aTime) {
+  mCurrentAnimationFrameTime = aTime;
+}
+
+bool AnimationState::MaybeAdvanceAnimationFrameTime(const TimeStamp& aTime) {
+  if (!StaticPrefs::image_animated_resume_from_last_displayed() ||
+      mCurrentAnimationFrameTime >= aTime) {
+    return false;
+  }
+
+  // We are configured to stop an animation when it is out of view, and restart
+  // it from the same point when it comes back into view. The same applies if it
+  // was discarded while out of view.
+  mCurrentAnimationFrameTime = aTime;
+  return true;
+}
+
+uint32_t AnimationState::GetCurrentAnimationFrameIndex() const {
+  return mCurrentAnimationFrameIndex;
+}
+
+FrameTimeout AnimationState::LoopLength() const {
+  // If we don't know the loop length yet, we have to treat it as infinite.
+  if (!mLoopLength) {
+    return FrameTimeout::Forever();
+  }
+
+  MOZ_ASSERT(mHasBeenDecoded,
+             "We know the loop length but decoding isn't done?");
+
+  // If we're not looping, a single loop time has no meaning.
+  if (mAnimationMode != imgIContainer::kNormalAnimMode) {
+    return FrameTimeout::Forever();
+  }
+
+  return *mLoopLength;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// FrameAnimator implementation.
+///////////////////////////////////////////////////////////////////////////////
+
+TimeStamp FrameAnimator::GetCurrentImgFrameEndTime(
+    AnimationState& aState, FrameTimeout aCurrentTimeout) const {
+  if (aCurrentTimeout == FrameTimeout::Forever()) {
+    // We need to return a sentinel value in this case, because our logic
+    // doesn't work correctly if we have an infinitely long timeout. We use one
+    // year in the future as the sentinel because it works with the loop in
+    // RequestRefresh() below.
+    // XXX(seth): It'd be preferable to make our logic work correctly with
+    // infinitely long timeouts.
+    return TimeStamp::NowLoRes() + TimeDuration::FromMilliseconds(31536000.0);
+  }
+
+  TimeDuration durationOfTimeout =
+      TimeDuration::FromMilliseconds(double(aCurrentTimeout.AsMilliseconds()));
+  return aState.mCurrentAnimationFrameTime + durationOfTimeout;
+}
+
+RefreshResult FrameAnimator::AdvanceFrame(AnimationState& aState,
+                                          DrawableSurface& aFrames,
+                                          RefPtr<imgFrame>& aCurrentFrame,
+                                          TimeStamp aTime) {
+  AUTO_PROFILER_LABEL("FrameAnimator::AdvanceFrame", GRAPHICS);
+
+  RefreshResult ret;
+
+  // Determine what the next frame is, taking into account looping.
+  uint32_t currentFrameIndex = aState.mCurrentAnimationFrameIndex;
+  uint32_t nextFrameIndex = currentFrameIndex + 1;
+
+  // Check if we're at the end of the loop. (FrameCount() returns Nothing() if
+  // we don't know the total count yet.)
+  if (aState.FrameCount() == Some(nextFrameIndex)) {
+    // If we are not looping forever, initialize the loop counter
+    if (aState.mLoopRemainingCount < 0 && aState.LoopCount() >= 0) {
+      aState.mLoopRemainingCount = aState.LoopCount();
+    }
+
+    // If animation mode is "loop once", or we're at end of loop counter,
+    // it's time to stop animating.
+    if (aState.mAnimationMode == imgIContainer::kLoopOnceAnimMode ||
+        aState.mLoopRemainingCount == 0) {
+      ret.mAnimationFinished = true;
+    }
+
+    nextFrameIndex = 0;
+
+    if (aState.mLoopRemainingCount > 0) {
+      aState.mLoopRemainingCount--;
+    }
+
+    // If we're done, exit early.
+    if (ret.mAnimationFinished) {
+      return ret;
+    }
+  }
+
+  if (nextFrameIndex >= aState.KnownFrameCount()) {
+    // We've already advanced to the last decoded frame, nothing more we can do.
+    // We're blocked by network/decoding from displaying the animation at the
+    // rate specified, so that means the frame we are displaying (the latest
+    // available) is the frame we want to be displaying at this time. So we
+    // update the current animation time. If we didn't update the current
+    // animation time then it could lag behind, which would indicate that we are
+    // behind in the animation and should try to catch up. When we are done
+    // decoding (and thus can loop around back to the start of the animation) we
+    // would then jump to a random point in the animation to try to catch up.
+    // But we were never behind in the animation.
+    aState.mCurrentAnimationFrameTime = aTime;
+    return ret;
+  }
+
+  // There can be frames in the surface cache with index >= KnownFrameCount()
+  // which GetRawFrame() can access because an async decoder has decoded them,
+  // but which AnimationState doesn't know about yet because we haven't received
+  // the appropriate notification on the main thread. Make sure we stay in sync
+  // with AnimationState.
+  MOZ_ASSERT(nextFrameIndex < aState.KnownFrameCount());
+  RefPtr<imgFrame> nextFrame = aFrames.GetFrame(nextFrameIndex);
+
+  // We should always check to see if we have the next frame even if we have
+  // previously finished decoding. If we needed to redecode (e.g. due to a draw
+  // failure) we would have discarded all the old frames and may not yet have
+  // the new ones. DrawableSurface::RawAccessRef promises to only return
+  // finished frames.
+  if (!nextFrame) {
+    // Uh oh, the frame we want to show is currently being decoded (partial).
+    // Similar to the above case, we could be blocked by network or decoding,
+    // and so we should advance our current time rather than risk jumping
+    // through the animation. We will wait until the next refresh driver tick
+    // and try again.
+    aState.mCurrentAnimationFrameTime = aTime;
+    return ret;
+  }
+
+  if (nextFrame->GetTimeout() == FrameTimeout::Forever()) {
+    ret.mAnimationFinished = true;
+  }
+
+  if (nextFrameIndex == 0) {
+    ret.mDirtyRect = aState.FirstFrameRefreshArea();
+  } else {
+    ret.mDirtyRect = nextFrame->GetDirtyRect();
+  }
+
+  aState.mCurrentAnimationFrameTime =
+      GetCurrentImgFrameEndTime(aState, aCurrentFrame->GetTimeout());
+
+  // If we can get closer to the current time by a multiple of the image's loop
+  // time, we should. We can only do this if we're done decoding; otherwise, we
+  // don't know the full loop length, and LoopLength() will have to return
+  // FrameTimeout::Forever(). We also skip this for images with a finite loop
+  // count if we have initialized mLoopRemainingCount (it only gets initialized
+  // after one full loop).
+  FrameTimeout loopTime = aState.LoopLength();
+  if (loopTime != FrameTimeout::Forever() &&
+      (aState.LoopCount() < 0 || aState.mLoopRemainingCount >= 0)) {
+    TimeDuration delay = aTime - aState.mCurrentAnimationFrameTime;
+    if (delay.ToMilliseconds() > loopTime.AsMilliseconds()) {
+      // Explicitly use integer division to get the floor of the number of
+      // loops.
+      uint64_t loops = static_cast<uint64_t>(delay.ToMilliseconds()) /
+                       loopTime.AsMilliseconds();
+
+      // If we have a finite loop count limit the number of loops we advance.
+      if (aState.mLoopRemainingCount >= 0) {
+        MOZ_ASSERT(aState.LoopCount() >= 0);
+        loops =
+            std::min(loops, CheckedUint64(aState.mLoopRemainingCount).value());
+      }
+
+      aState.mCurrentAnimationFrameTime +=
+          TimeDuration::FromMilliseconds(loops * loopTime.AsMilliseconds());
+
+      if (aState.mLoopRemainingCount >= 0) {
+        MOZ_ASSERT(loops <= CheckedUint64(aState.mLoopRemainingCount).value());
+        aState.mLoopRemainingCount -= CheckedInt32(loops).value();
+      }
+    }
+  }
+
+  // Set currentAnimationFrameIndex at the last possible moment
+  aState.mCurrentAnimationFrameIndex = nextFrameIndex;
+  aCurrentFrame = std::move(nextFrame);
+  aFrames.Advance(nextFrameIndex);
+
+  // If we're here, we successfully advanced the frame.
+  ret.mFrameAdvanced = true;
+
+  return ret;
+}
+
+void FrameAnimator::ResetAnimation(AnimationState& aState) {
+  aState.ResetAnimation();
+
+  // Our surface provider is synchronized to our state, so we need to reset its
+  // state as well, if we still have one.
+  SurfaceCache::ResetAnimation(
+      ImageKey(mImage),
+      RasterSurfaceKey(mSize, DefaultSurfaceFlags(), PlaybackType::eAnimated));
+
+  // Calling Reset on the surface of the animation can cause discarding surface
+  // providers to throw out all their frames so refresh our state.
+  OrientedIntRect rect =
+      OrientedIntRect::FromUnknownRect(aState.UpdateState(mImage, mSize));
+
+  if (!rect.IsEmpty()) {
+    nsCOMPtr<nsIEventTarget> eventTarget = do_GetMainThread();
+    RefPtr<RasterImage> image = mImage;
+    nsCOMPtr<nsIRunnable> ev = NS_NewRunnableFunction(
+        "FrameAnimator::ResetAnimation",
+        [=]() -> void { image->NotifyProgress(NoProgress, rect); });
+    eventTarget->Dispatch(ev.forget(), NS_DISPATCH_NORMAL);
+  }
+}
+
+RefreshResult FrameAnimator::RequestRefresh(AnimationState& aState,
+                                            const TimeStamp& aTime) {
+  // By default, an empty RefreshResult.
+  RefreshResult ret;
+
+  if (aState.IsDiscarded()) {
+    aState.MaybeAdvanceAnimationFrameTime(aTime);
+    return ret;
+  }
+
+  // Get the animation frames once now, and pass them down to callees because
+  // the surface could be discarded at anytime on a different thread. This is
+  // must easier to reason about then trying to write code that is safe to
+  // having the surface disappear at anytime.
+  LookupResult result = SurfaceCache::Lookup(
+      ImageKey(mImage),
+      RasterSurfaceKey(mSize, DefaultSurfaceFlags(), PlaybackType::eAnimated),
+      /* aMarkUsed = */ true);
+
+  ret.mDirtyRect = aState.UpdateStateInternal(result, mSize);
+  if (aState.IsDiscarded() || !result) {
+    aState.MaybeAdvanceAnimationFrameTime(aTime);
+    return ret;
+  }
+
+  RefPtr<imgFrame> currentFrame =
+      result.Surface().GetFrame(aState.mCurrentAnimationFrameIndex);
+
+  // only advance the frame if the current time is greater than or
+  // equal to the current frame's end time.
+  if (!currentFrame) {
+    MOZ_ASSERT(StaticPrefs::image_mem_animated_discardable_AtStartup());
+    MOZ_ASSERT(aState.GetHasRequestedDecode() &&
+               !aState.GetIsCurrentlyDecoded());
+    MOZ_ASSERT(aState.mCompositedFrameInvalid);
+    // Nothing we can do but wait for our previous current frame to be decoded
+    // again so we can determine what to do next.
+    aState.MaybeAdvanceAnimationFrameTime(aTime);
+    return ret;
+  }
+
+  TimeStamp currentFrameEndTime =
+      GetCurrentImgFrameEndTime(aState, currentFrame->GetTimeout());
+
+  // If nothing has accessed the composited frame since the last time we
+  // advanced, then there is no point in continuing to advance the animation.
+  // This has the effect of freezing the animation while not in view.
+  if (!result.Surface().MayAdvance() &&
+      aState.MaybeAdvanceAnimationFrameTime(aTime)) {
+    return ret;
+  }
+
+  while (currentFrameEndTime <= aTime) {
+    TimeStamp oldFrameEndTime = currentFrameEndTime;
+
+    RefreshResult frameRes =
+        AdvanceFrame(aState, result.Surface(), currentFrame, aTime);
+
+    // Accumulate our result for returning to callers.
+    ret.Accumulate(frameRes);
+
+    // currentFrame was updated by AdvanceFrame so it is still current.
+    currentFrameEndTime =
+        GetCurrentImgFrameEndTime(aState, currentFrame->GetTimeout());
+
+    // If we didn't advance a frame, and our frame end time didn't change,
+    // then we need to break out of this loop & wait for the frame(s)
+    // to finish downloading.
+    if (!frameRes.mFrameAdvanced && currentFrameEndTime == oldFrameEndTime) {
+      break;
+    }
+  }
+
+  // We should only mark the composited frame as valid and reset the dirty rect
+  // if we advanced (meaning the next frame was actually produced somehow), the
+  // composited frame was previously invalid (so we may need to repaint
+  // everything) and either the frame index is valid (to know we were doing
+  // blending on the main thread, instead of on the decoder threads in advance),
+  // or the current frame is a full frame (blends off the main thread).
+  //
+  // If for some reason we forget to reset aState.mCompositedFrameInvalid, then
+  // GetCompositedFrame will fail, even if we have all the data available for
+  // display.
+  if (currentFrameEndTime > aTime && aState.mCompositedFrameInvalid) {
+    aState.mCompositedFrameInvalid = false;
+    ret.mDirtyRect = IntRect(IntPoint(0, 0), mSize);
+  }
+
+  MOZ_ASSERT(!aState.mIsCurrentlyDecoded || !aState.mCompositedFrameInvalid);
+
+  return ret;
+}
+
+LookupResult FrameAnimator::GetCompositedFrame(AnimationState& aState,
+                                               bool aMarkUsed) {
+  LookupResult result = SurfaceCache::Lookup(
+      ImageKey(mImage),
+      RasterSurfaceKey(mSize, DefaultSurfaceFlags(), PlaybackType::eAnimated),
+      aMarkUsed);
+
+  if (result) {
+    // If we are getting the frame directly (e.g. through tests or canvas), we
+    // need to ensure the animation is marked to allow advancing to the next
+    // frame.
+    result.Surface().MarkMayAdvance();
+  }
+
+  if (aState.mCompositedFrameInvalid) {
+    MOZ_ASSERT(StaticPrefs::image_mem_animated_discardable_AtStartup());
+    MOZ_ASSERT(aState.GetHasRequestedDecode());
+    MOZ_ASSERT(!aState.GetIsCurrentlyDecoded());
+
+    if (result.Type() == MatchType::EXACT) {
+      // If our composited frame is marked as invalid but our frames are in the
+      // surface cache we might just have not updated our internal state yet.
+      // This can happen if the image is not in a document so that
+      // RequestRefresh is not getting called to advance the frame.
+      // RequestRefresh would result in our composited frame getting marked as
+      // valid either at the end of RequestRefresh when we are able to advance
+      // to the current time or if advancing frames eventually causes us to
+      // decode all of the frames of the image resulting in DecodeComplete
+      // getting called which calls UpdateState. The reason we care about this
+      // is that img.decode promises won't resolve until GetCompositedFrame
+      // returns a frame.
+      OrientedIntRect rect = OrientedIntRect::FromUnknownRect(
+          aState.UpdateStateInternal(result, mSize));
+
+      if (!rect.IsEmpty()) {
+        nsCOMPtr<nsIEventTarget> eventTarget = do_GetMainThread();
+        RefPtr<RasterImage> image = mImage;
+        nsCOMPtr<nsIRunnable> ev = NS_NewRunnableFunction(
+            "FrameAnimator::GetCompositedFrame",
+            [=]() -> void { image->NotifyProgress(NoProgress, rect); });
+        eventTarget->Dispatch(ev.forget(), NS_DISPATCH_NORMAL);
+      }
+    }
+
+    // If it's still invalid we have to return.
+    if (aState.mCompositedFrameInvalid) {
+      if (result.Type() == MatchType::NOT_FOUND) {
+        return result;
+      }
+      return LookupResult(MatchType::PENDING);
+    }
+  }
+
+  // Otherwise return the raw frame. DoBlend is required to ensure that we only
+  // hit this case if the frame is not paletted and doesn't require compositing.
+  if (!result) {
+    return result;
+  }
+
+  // Seek to the appropriate frame. If seeking fails, it means that we couldn't
+  // get the frame we're looking for; treat this as if the lookup failed.
+  if (NS_FAILED(result.Surface().Seek(aState.mCurrentAnimationFrameIndex))) {
+    if (result.Type() == MatchType::NOT_FOUND) {
+      return result;
+    }
+    return LookupResult(MatchType::PENDING);
+  }
+
+  return result;
+}
+
+}  // namespace image
+}  // namespace mozilla