1300459 - [CID 1372416] Inefficient pass-by-value: HTMLMediaElement::SetMediaInfo(mozilla::MediaInfo)

Status: RESOLVED FIXED

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

Description

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

> *** CID 1372416:  Performance inefficiencies  (PASS_BY_VALUE)
> /dom/html/HTMLMediaElement.cpp: 6544 in
> mozilla::dom::HTMLMediaElement::SetMediaInfo(mozilla::MediaInfo)()
> 6538       }
> 6539     
> 6540       return false;
> 6541     }
> 6542     
> 6543     void
>   CID 1372416:  Performance inefficiencies  (PASS_BY_VALUE)
>   Passing parameter aInfo of type "mozilla::MediaInfo const"
>   (size 472 bytes) by value.
> 6544     HTMLMediaElement::SetMediaInfo(const MediaInfo aInfo)
> 6545     {
> 6546       mMediaInfo = aInfo;
> 6547       AudioCaptureStreamChangeIfNeeded();
> 6548     }

It should be non-controversial to pass by const-ref instead, since the argument is immediately copied into a member variable anyway. This would save one copy.

We might even benefit from move semantics, but that could be a later improvement if needed.

Comment 1

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Attachment: Bug 1300459 - Pass MediaInfo by const-ref to SetMediaInfo -

Review commit: https://reviewboard.mozilla.org/r/76584/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/76584/

Comment 2

[Jean-Yves Avenard [:jya]]

Comment on attachment 8788037 [details]
Bug 1300459 - Pass MediaInfo by const-ref to SetMediaInfo -

https://reviewboard.mozilla.org/r/76584/#review74714

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6681da2c7663
Pass MediaInfo by const-ref to SetMediaInfo - r=jya

Comment 4

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/6681da2c7663

Comment 5

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Alastor, you might be interested in this change here, as you first introduced SetMediaInfo in https://hg.mozilla.org/mozilla-central/rev/e7a17f7ee53d for bug 1262053.

Comment 6

[Alastor Wu [:alwu]]

Thanks Gerald!