DrawableFrameRef
DecodedSurfaceProvider::DrawableRef(size_t aFrame)
{
MOZ_ASSERT(aFrame == 0,
"Requesting an animation frame from a DecodedSurfaceProvider?");
// We depend on SurfaceCache::SurfaceAvailable() to provide synchronization
// for methods that touch |mSurface|; after SurfaceAvailable() is called,
// |mSurface| should be non-null and shouldn't be mutated further until we get
// destroyed. That means that the assertions below are very important; we'll
// end up with data races if these assumptions are violated.
if (Availability().IsPlaceholder()) {
MOZ_ASSERT_UNREACHABLE("Calling DrawableRef() on a placeholder");
return DrawableFrameRef();
}
if (!mSurface) {
MOZ_ASSERT_UNREACHABLE("Calling DrawableRef() when we have no surface");
return DrawableFrameRef();
}
return mSurface->DrawableRef();
}
DrawableFrameRef
AnimationSurfaceProvider::DrawableRef(size_t aFrame)
{
MutexAutoLock lock(mFramesMutex);
if (Availability().IsPlaceholder()) {
MOZ_ASSERT_UNREACHABLE("Calling DrawableRef() on a placeholder");
return DrawableFrameRef();
}
if (mFrames.IsEmpty()) {
MOZ_ASSERT_UNREACHABLE("Calling DrawableRef() when we have no frames");
return DrawableFrameRef();
}
// If we don't have that frame, return an empty frame ref.
if (aFrame >= mFrames.Length()) {
return DrawableFrameRef();
}
// We've got the requested frame. Return it.
MOZ_ASSERT(mFrames[aFrame]);
return mFrames[aFrame]->DrawableRef();
}
void
DecodedSurfaceProvider::SetLocked(bool aLocked)
{
// See DrawableRef() for commentary on these assertions.
if (Availability().IsPlaceholder()) {
MOZ_ASSERT_UNREACHABLE("Calling SetLocked() on a placeholder");
return;
}
if (!mSurface) {
MOZ_ASSERT_UNREACHABLE("Calling SetLocked() when we have no surface");
return;
}
if (aLocked == IsLocked()) {
return; // Nothing to do.
}
// If we're locked, hold a DrawableFrameRef to |mSurface|, which will keep any
// volatile buffer it owns in memory.
mLockRef = aLocked ? mSurface->DrawableRef()
: DrawableFrameRef();
}
