1308071 - Change the type of MDSM::mInfo to Maybe<MediaInfo>

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, defect, P3)

Description

[JW Wang [:jwwang] [:jw_wang]]

This helps catch invalid usage of mInfo before reading metadata.

Comment 1

[JW Wang [:jwwang] [:jw_wang]]

Attachment: Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

Review commit: https://reviewboard.mozilla.org/r/84796/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/84796/

Comment 2

[JW Wang [:jwwang] [:jw_wang]]

Attachment: Bug 1308071. Part 2 - remove unused members.

Review commit: https://reviewboard.mozilla.org/r/84798/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/84798/

Comment 3

[JW Wang [:jwwang] [:jw_wang]]

Attachment: Bug 1308071. Part 3 - early return from VisibilityChanged() if mInfo is nothing.

VisibilityChanged() could be called before reading metadata.

Review commit: https://reviewboard.mozilla.org/r/84800/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/84800/

Comment 4

[Tzuhao Kuo [:kaku]]

Comment on attachment 8799662 [details]
Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

https://reviewboard.mozilla.org/r/84796/#review83378

::: dom/media/MediaDecoderStateMachine.h:310
(Diff revision 1)
>  
>    MediaStatistics GetStatistics();
>  
> -  // This is called on the state machine thread and audio thread.
> -  // The decoder monitor must be obtained before calling this.
> -  bool HasAudio() const {
> +  bool HasAudio() const { return mInfo.ref().HasAudio(); }
> +  bool HasVideo() const { return mInfo.ref().HasVideo(); }
> +  MediaInfo& Info() { return mInfo.ref(); }

Should be constified.

::: dom/media/MediaDecoderStateMachine.cpp:315
(Diff revision 1)
> +    MediaInfo& info = Info();
>  
> -    if (mMaster->mInfo.mMetadataDuration.isSome()) {
> +    if (info.mMetadataDuration.isSome()) {
>        mMaster->RecomputeDuration();
> -    } else if (mMaster->mInfo.mUnadjustedMetadataEndTime.isSome()) {
> +    } else if (info.mUnadjustedMetadataEndTime.isSome()) {
>        RefPtr<Master> master = mMaster;
>        Reader()->AwaitStartTime()->Then(OwnerThread(), __func__,
> -        [master] () {
> +        [master, &info] () {
>            NS_ENSURE_TRUE_VOID(!master->IsShutdown());
> -          TimeUnit unadjusted = master->mInfo.mUnadjustedMetadataEndTime.ref();
> +          TimeUnit unadjusted = info.mUnadjustedMetadataEndTime.ref();
>            TimeUnit adjustment = master->mReader->StartTime();
> -          master->mInfo.mMetadataDuration.emplace(unadjusted - adjustment);
> +          info.mMetadataDuration.emplace(unadjusted - adjustment);

Not really a problem, but since you use StateObject::Info() everywhere, why do you use a temporary reference here?

Comment 5

[Tzuhao Kuo [:kaku]]

Comment on attachment 8799664 [details]
Bug 1308071. Part 3 - early return from VisibilityChanged() if mInfo is nothing.

https://reviewboard.mozilla.org/r/84800/#review83402

Comment 6

[Tzuhao Kuo [:kaku]]

Comment on attachment 8799663 [details]
Bug 1308071. Part 2 - remove unused members.

https://reviewboard.mozilla.org/r/84798/#review83396

Comment 7

[JW Wang [:jwwang] [:jw_wang]]

Comment on attachment 8799662 [details]
Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

https://reviewboard.mozilla.org/r/84796/#review83440

::: dom/media/MediaDecoderStateMachine.h:310
(Diff revision 1)
>  
>    MediaStatistics GetStatistics();
>  
> -  // This is called on the state machine thread and audio thread.
> -  // The decoder monitor must be obtained before calling this.
> -  bool HasAudio() const {
> +  bool HasAudio() const { return mInfo.ref().HasAudio(); }
> +  bool HasVideo() const { return mInfo.ref().HasVideo(); }
> +  MediaInfo& Info() { return mInfo.ref(); }

Will do.

::: dom/media/MediaDecoderStateMachine.cpp:315
(Diff revision 1)
> +    MediaInfo& info = Info();
>  
> -    if (mMaster->mInfo.mMetadataDuration.isSome()) {
> +    if (info.mMetadataDuration.isSome()) {
>        mMaster->RecomputeDuration();
> -    } else if (mMaster->mInfo.mUnadjustedMetadataEndTime.isSome()) {
> +    } else if (info.mUnadjustedMetadataEndTime.isSome()) {
>        RefPtr<Master> master = mMaster;
>        Reader()->AwaitStartTime()->Then(OwnerThread(), __func__,
> -        [master] () {
> +        [master, &info] () {
>            NS_ENSURE_TRUE_VOID(!master->IsShutdown());
> -          TimeUnit unadjusted = master->mInfo.mUnadjustedMetadataEndTime.ref();
> +          TimeUnit unadjusted = info.mUnadjustedMetadataEndTime.ref();
>            TimeUnit adjustment = master->mReader->StartTime();
> -          master->mInfo.mMetadataDuration.emplace(unadjusted - adjustment);
> +          info.mMetadataDuration.emplace(unadjusted - adjustment);

So I can capture |info| at #322.

However, it is not clear what keeps |info| valid in the lambda. I will declare |auto& info = master->mInfo.ref()| inside the lambda to make it clear.

Comment 8

[Tzuhao Kuo [:kaku]]

Comment on attachment 8799662 [details]
Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

https://reviewboard.mozilla.org/r/84796/#review83440

> So I can capture |info| at #322.
> 
> However, it is not clear what keeps |info| valid in the lambda. I will declare |auto& info = master->mInfo.ref()| inside the lambda to make it clear.

Since you have captured master, how about just replacing |master->mInfo| to |master->Info()|?

Comment 9

[JW Wang [:jwwang] [:jw_wang]]

Comment on attachment 8799662 [details]
Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

https://reviewboard.mozilla.org/r/84796/#review83440

> Since you have captured master, how about just replacing |master->mInfo| to |master->Info()|?

We can't. |info| needs to be a mutable reference in the lambda while we want MDSM::Info() to be a const function (and thus returning a const reference).

Comment 10

[Tzuhao Kuo [:kaku]]

Comment on attachment 8799662 [details]
Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

https://reviewboard.mozilla.org/r/84796/#review83440

> We can't. |info| needs to be a mutable reference in the lambda while we want MDSM::Info() to be a const function (and thus returning a const reference).

Right, thanks!

Comment 11

[JW Wang [:jwwang] [:jw_wang]]

Comment on attachment 8799662 [details]
Bug 1308071. Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/84796/diff/1-2/

Comment 12

[JW Wang [:jwwang] [:jw_wang]]

Comment on attachment 8799663 [details]
Bug 1308071. Part 2 - remove unused members.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/84798/diff/1-2/

Comment 13

[JW Wang [:jwwang] [:jw_wang]]

Comment on attachment 8799664 [details]
Bug 1308071. Part 3 - early return from VisibilityChanged() if mInfo is nothing.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/84800/diff/1-2/

Comment 14

[JW Wang [:jwwang] [:jw_wang]]

Thanks for the review!

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8ec690c69bbc
Part 1 - Change the type of MDSM::mInfo to Maybe<MediaInfo>. r=kaku
https://hg.mozilla.org/integration/autoland/rev/44ab9ccc6c9d
Part 2 - remove unused members. r=kaku
https://hg.mozilla.org/integration/autoland/rev/d052f81bef3c
Part 3 - early return from VisibilityChanged() if mInfo is nothing. r=kaku

Comment 16

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/8ec690c69bbc
https://hg.mozilla.org/mozilla-central/rev/44ab9ccc6c9d
https://hg.mozilla.org/mozilla-central/rev/d052f81bef3c