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Bug 1435134 - Don't play until we've reached metadata. r=bryce

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We want to block playback of media which have an audio track, so if play()
is called before the load of the resource has loaded metadata, we need to
delay starting playback and resolving the play promise until we've figured
out whether the media has audio. So if play() is called before we've reached
readyState >= HAVE_METADATA, set a flag, and check that flag when we do
reach HAVE_METADATA and start the play and resolve the promise then.

MozReview-Commit-ID: 1K06NK2kfpw
This commit is contained in:
Chris Pearce
2018-03-13 16:40:18 +13:00
parent 8c15e6bd68
commit cbff3c0a1d
2 changed files with 49 additions and 16 deletions
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58
dom/html/HTMLMediaElement.cpp
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@@ -1808,6 +1808,7 @@ void HTMLMediaElement::AbortExistingLoads()
mPendingEncryptedInitData.Reset();
mWaitingForKey = NOT_WAITING_FOR_KEY;
mSourcePointer = nullptr;
mAttemptPlayUponLoadedMetadata = false;
mTags = nullptr;
@@ -3956,7 +3957,7 @@ HTMLMediaElement::NotifyXPCOMShutdown()
already_AddRefed<Promise>
HTMLMediaElement::Play(ErrorResult& aRv)
{
LOG(LogLevel::Debug, ("%p Play() called by JS", this));
LOG(LogLevel::Debug, ("%p Play() called by JS readyState=%d", this, mReadyState));
if (mAudioChannelWrapper && mAudioChannelWrapper->IsPlaybackBlocked()) {
MaybeDoLoad();
@@ -3995,7 +3996,12 @@ HTMLMediaElement::PlayInternal(ErrorResult& aRv)
// 4.8.12.8 - Step 1:
// If the media element is not allowed to play, return a promise rejected
// with a "NotAllowedError" DOMException and abort these steps.
if (!IsAllowedToPlay()) {
// Note: IsAllowedToPlay() needs to know whether there is an audio track
// in the resource, and for that we need to be at readyState HAVE_METADATA
// or above. So only reject here if we're at readyState HAVE_METADATA. If
// we're below that, we'll we delay fulfilling the play promise until we've
// reached readyState >= HAVE_METADATA below.
if (mReadyState >= HAVE_METADATA && !IsAllowedToPlay()) {
// NOTE: for promise-based-play, will return a rejected promise here.
LOG(LogLevel::Debug,
("%p Play() promise rejected because not allowed to play.", this));
@@ -4053,21 +4059,30 @@ HTMLMediaElement::PlayInternal(ErrorResult& aRv)
SetCurrentTime(0);
}
if (!mPausedForInactiveDocumentOrChannel) {
nsresult rv = mDecoder->Play();
if (NS_FAILED(rv)) {
// We don't need to remove the _promise_ from _mPendingPlayPromises_ here.
// If something wrong between |mPendingPlayPromises.AppendElement(promise);|
// and here, the _promise_ should already have been rejected. Otherwise,
// the _promise_ won't be returned to JS at all, so just leave it in the
// _mPendingPlayPromises_ and let it be resolved/rejected with the
// following actions and the promise-resolution won't be observed at all.
LOG(LogLevel::Debug,
("%p Play() promise rejected because failed to play MediaDecoder.",
this));
aRv.Throw(rv);
return nullptr;
if (mReadyState < HAVE_METADATA) {
// We don't know whether the autoplay policy will allow us to play yet,
// as we don't yet know whether the media has audio tracks. So delay
// starting playback until we've loaded metadata.
mAttemptPlayUponLoadedMetadata = true;
} else {
nsresult rv = mDecoder->Play();
if (NS_FAILED(rv)) {
// We don't need to remove the _promise_ from _mPendingPlayPromises_ here.
// If something wrong between |mPendingPlayPromises.AppendElement(promise);|
// and here, the _promise_ should already have been rejected. Otherwise,
// the _promise_ won't be returned to JS at all, so just leave it in the
// _mPendingPlayPromises_ and let it be resolved/rejected with the
// following actions and the promise-resolution won't be observed at all.
LOG(LogLevel::Debug,
("%p Play() promise rejected because failed to play MediaDecoder.",
this));
aRv.Throw(rv);
return nullptr;
}
}
}
} else if (mReadyState < HAVE_METADATA) {
mAttemptPlayUponLoadedMetadata = true;
}
if (mCurrentPlayRangeStart == -1.0) {
@@ -4926,7 +4941,7 @@ HTMLMediaElement::FinishDecoderSetup(MediaDecoder* aDecoder)
}
nsresult rv = NS_OK;
if (!mPaused) {
if (!mPaused && !mAttemptPlayUponLoadedMetadata) {
SetPlayedOrSeeked(true);
if (!mPausedForInactiveDocumentOrChannel) {
rv = mDecoder->Play();
@@ -5930,6 +5945,15 @@ HTMLMediaElement::ChangeReadyState(nsMediaReadyState aState)
mReadyState >= HAVE_FUTURE_DATA) {
DispatchAsyncEvent(NS_LITERAL_STRING("canplay"));
if (!mPaused) {
if (mAttemptPlayUponLoadedMetadata && mDecoder) {
mAttemptPlayUponLoadedMetadata = false;
if (IsAllowedToPlay()) {
mDecoder->Play();
} else {
AsyncRejectPendingPlayPromises(NS_ERROR_DOM_MEDIA_NOT_ALLOWED_ERR);
mPaused = true;
}
}
NotifyAboutPlaying();
}
}
@@ -6050,6 +6074,7 @@ void HTMLMediaElement::CheckAutoplayDataReady()
if (mCurrentPlayRangeStart == -1.0) {
mCurrentPlayRangeStart = CurrentTime();
}
MOZ_ASSERT(!mAttemptPlayUponLoadedMetadata);
mDecoder->Play();
} else if (mSrcStream) {
SetPlayedOrSeeked(true);
@@ -6387,6 +6412,7 @@ void HTMLMediaElement::SuspendOrResumeElement(bool aPauseElement, bool aSuspendE
if (mDecoder) {
mDecoder->Resume();
if (!mPaused && !mDecoder->IsEnded()) {
MOZ_ASSERT(!mAttemptPlayUponLoadedMetadata);
mDecoder->Play();
}
}