When an animated image has been discarded, we avoided marking the
composited frame invalid unless it had been previously decoded. Most of
the time this was fine, but if the animated image was still decoding for
the first time, then we still had a composited frame lingering that we
did not mark as invalid. As a result, when we called
RasterImage::LookupFrame (and indirectly
FrameAnimator::GetCompositedFrame), it would always return the
composited frame. This meant that RasterImage::Decode would never be
called to trigger a redecode. At the same time,
FrameAnimator::RequestRefresh would not cause us to advance the frame
because the state was still discarded.
With this patch we separate out the concepts of "has ever requested to
be decoded" and "has ever completed decoding." The former is now used to
control whether or not a composited frame is marked as invalid after we
discover we currently have no surface for the animation -- this solves
the animation remaining frozen as we now request the redecode as
expected. The latter remains used to determine if we actually know the
total number of frames.
This patch makes the following changes to the macros.
- Removes PROFILER_LABEL_FUNC. It's only suitable for use in functions outside
classes, due to PROFILER_FUNCTION_NAME not getting class names, and it was
mostly misused.
- Removes PROFILER_FUNCTION_NAME. It's no longer used, and __func__ is
universally available now anyway.
- Combines the first two string literal arguments of PROFILER_LABEL and
PROFILER_LABEL_DYNAMIC into a single argument. There was no good reason for
them to be separate, and it forced a '::' in the label, which isn't always
appropriate. Also, the meaning of the "name_space" argument was interpreted
in an interesting variety of ways.
- Adds an "AUTO_" prefix to PROFILER_LABEL and PROFILER_LABEL_DYNAMIC, to make
it clearer they construct RAII objects rather than just being function calls.
(I myself have screwed up the scoping because of this in the past.)
- Fills in the 'js::ProfileEntry::Category::' qualifier within the macro, so
the caller doesn't need to. This makes a *lot* more of the uses fit onto a
single line.
The patch also makes the following changes to the macro uses (beyond those
required by the changes described above).
- Fixes a bunch of labels that had gotten out of sync with the name of the
class and/or function that encloses them.
- Removes a useless PROFILER_LABEL use within a trivial scope in
EventStateManager::DispatchMouseOrPointerEvent(). It clearly wasn't serving
any useful purpose. It also serves as extra evidence that the AUTO_ prefix is
a good idea.
- Tweaks DecodePool::SyncRunIf{Preferred,Possible} so that the labelling is
done within them, instead of at their callsites, because that's a more
standard way of doing things.
--HG--
extra : rebase_source : 318d1bc6fc1425a94aacbf489dd46e4f83211de4
We invalidate if FrameAnimator::UpdateState marks the composited frame as valid, but we fail to do so if FrameAnimator::RequestRefresh does so.
The other place that sets the composited frame as valid is RasterImage::Decode. This call is actually redundant because the UpdateState call will do the same.
Even though we will invalidate when the decode produces results we could still draw incorrectly if something else invalidates. In which case we would only draw the part of the image that was invalidated. But that should actually be impossible as explained in the comment.
We invalidate if FrameAnimator::UpdateState marks the composited frame as valid, but we fail to do so if FrameAnimator::RequestRefresh does so.
The other place that sets the composited frame as valid is RasterImage::Decode. This call is actually redundant because the UpdateState call will do the same.
Even though we will invalidate when the decode produces results we could still draw incorrectly if something else invalidates. In which case we would only draw the part of the image that was invalidated. But that should actually be impossible as explained in the comment.
We draw nothing when the composited frame is invalid, so when we mark it valid we should invalidate. Usually the action that causes the composited frame to be valid will invalidate (ie RequestRefresh).
If the SurfaceCache discards our frames on another thread, the runnable that notifies us of that discard could race with a decode complete notification. So we can't rely on any ordering of SetDiscarded and NotifyDecodeComplete. Thus we must derive our state purely from the SurfaceCache (and mAnimationFinished from RasterImage).
We also update the image state in RequestRefresh (the main place where we use the state that is updated).
The other main place we use the state is GetCompositedFrame, but we don't update the state there. It should be fine because the only time this might lag behind reality is if the frames are discarded, and it should be fine to continue drawing the composited frame until the discard notification arrives.
The way that we tell that an animated image has all of its frames complete in the surface cache is less than ideal.
The SurfaceCache can discard on any thread at any time. So we could be in the middle of advancing frames of a fully decoded animated image and then the frames could disappear out from under us.
Making the code deal with that kind of a situation would make the logic very complicated. So instead just look up the frames once and pass them around, that way they never change during while we are advancing the frame.
Do this to allow GetTimeoutForFrame to be called for frames that haven't been decoded yet. Propagate a Maybe result where it makes sense. The remaining callers just bail if they get no return value. Many of them can just assert that they get a return value because they already got the same frame, so the timeout has to be available.
The logic is a little tricky because we have "Forever" timeouts that were sort of treated as error cases.
For animated images with finite animations we can finish running their animation. At which point we won't call RequestRefresh, and so we will never mark the composited frame as valid (since that is the only place we do that).
To fix this we mark the composited frame as valid when we finish decoding.
But we can do better than that, we can mark the composited frame as valid immediately when we create a new decoded since we are just drawing the final frame from now on.
When we allow animated images to be discarded we still want to track if the image has been fully decoded before, but it would be confusing to say that it is "done decoding" because that sounds like the image is currently decoded, even though it could be discarded at the time.
FrameAnimator::GetCompositedFrame is only ever called with the current animation frame index. This is good because it can return invalid results if it is called for some other frame number.
This means that in RasterImage::LookupFrame when we are asked to do a sync decode (if needed) we use WaitUntilComplete to wait until the frame is finished decoding. But we would actually return after the next progressive pass notified the monitor to wake up. Thus, we would draw a not-fully-decoded image even though the sync decode flag was passed.
The change in FrameAnimator means that we won't draw the next frame in an animated image until all progressive passes of that image are complete. This seems like what we want anyways.
There is one real use of IsImageComplete left, in imgFrame::Draw, where we need to know if the decoded image data covers the whole image frame. (There are a couple of uses of IsImageComplete in asserts.)
When storing ms, 32 bit ints can hold 2^32/1000/60/60/24 ~= 49 days. It's quite conceivable that someone would leave a tab in the background for 50 days.
GetSingleLoopTime returns -1 on exceptional cases but we used an unsigned int to hold the return value in AdvanceFrame. So the |loopTime > 0| check would succeed. Fortunately the |delay.ToMilliseconds() > loopTime| check would fail because loopTime was MAX_UNIT32, so we didn't do anything incorrect.
http://hg.mozilla.org/mozilla-central/rev/263980931d1b (bug 890743) changed GetSingleLoopTime from returning 0 (and uint32_t) to -1 (and int32_t) on exceptional cases. But the caller of GetSingleLoopTime wasn't updated.
Andrew Osmond
Milan Sreckovic
Nicholas Nethercote
Timothy Nikkel
Iris Hsiao
Seth Fowler