1293940 - [Coverity #749800][Uninitialized members] /dom/media/MediaCache.cpp: 280 in mozilla::MediaCache::BlockOwner::BlockOwner()()

Status: RESOLVED FIXED

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

Description

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

*** CID 749800:  Uninitialized members  (UNINIT_CTOR)
/dom/media/MediaCache.cpp: 280 in mozilla::MediaCache::BlockOwner::BlockOwner()()
274         // offset is greater than or equal to the stream's current
275         // reader position
276         READAHEAD_BLOCK
277       };
278     
279       struct BlockOwner {

>>>     CID 749800:  Uninitialized members  (UNINIT_CTOR)
>>>     Non-static class member "mStreamBlock" is not initialized in this constructor nor in any functions that it calls.

280         BlockOwner() : mStream(nullptr), mClass(READAHEAD_BLOCK) {}
281     
282         // The stream that owns this block, or null if the block is free.
283         MediaCacheStream* mStream;
284         // The block index in the stream. Valid only if mStream is non-null.
285         uint32_t            mStreamBlock;

Comment 1

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

I've already marked it as "intentional" on Coverity's website, as I thought it was not a problem.
Of course, it would be easy to just initialize it to 0 for peace of mind, up to you.

Comment 2

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

Thanks! I still want to initialize them so it won't bother any other static analysis tools.

Comment 3

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

Attachment: Bug 1293940 - fix uninitialized members.

Review commit: https://reviewboard.mozilla.org/r/70618/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/70618/

Comment 4

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

Comment on attachment 8779643 [details]
Bug 1293940 - fix uninitialized members.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/70618/diff/1-2/

Comment 5

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

Comment on attachment 8779643 [details]
Bug 1293940 - fix uninitialized members.

https://reviewboard.mozilla.org/r/70618/#review68212

r+ with nit:

::: dom/media/MediaCache.cpp:285
(Diff revision 2)
> -    BlockOwner() : mStream(nullptr), mClass(READAHEAD_BLOCK) {}
> +    constexpr BlockOwner() {}
>  
>      // The stream that owns this block, or null if the block is free.
> -    MediaCacheStream* mStream;
> +    MediaCacheStream* mStream = nullptr;
>      // The block index in the stream. Valid only if mStream is non-null.
> -    uint32_t            mStreamBlock;
> +    // Initialized to an insane value to prevent misuse.

Strictly speaking, this won't *prevent* misuse.
How about "to highlight misuses" or similar?

Comment 6

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

Comment on attachment 8779643 [details]
Bug 1293940 - fix uninitialized members.

https://reviewboard.mozilla.org/r/70618/#review68212

> Strictly speaking, this won't *prevent* misuse.
> How about "to highlight misuses" or similar?

Yeah, thanks for the suggestion!

Comment 7

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

Comment on attachment 8779643 [details]
Bug 1293940 - fix uninitialized members.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/70618/diff/2-3/

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d2c07e16630c
fix uninitialized members. r=gerald

Comment 9

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

https://hg.mozilla.org/mozilla-central/rev/d2c07e16630c