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Improve several Read implementations #122441

Merged
merged 3 commits into from
May 4, 2024
Merged

Improve several Read implementations #122441

merged 3 commits into from
May 4, 2024

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a1phyr
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@a1phyr a1phyr commented Mar 13, 2024 •
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  • read_to_end and read_to_string for Cursor
  • Error on OOM in read_to_string of &[u8] and VecDeque<u8>
  • Avoid making the slices contiguous in VecDeque::read_to_string
  • read_exact and (unstable) read_buf_exact for Take
  • read_buf for UnixStream and &UnixStream (moved to UnixStream: override read_buf #123084)
  • read_to_end for ChildStdErr

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rustbot commented Mar 13, 2024

r? @ChrisDenton

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@rustbot rustbot added O-unix Operating system: Unix-like S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Mar 13, 2024
zachs18
zachs18 reviewed Mar 14, 2024
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Unrelated to code nits: Since Take::read_(buf_)exact don't actually call into the inner reader if buf.len() > self.limit, then you can get the weird case where take.read_exact(&mut long_buffer) returns EOF, but then immediately afterwards take.read_exact(&mut short_buffer) succeeds.

Perhaps self.limit should be set to 0 if Err(EOF) is returned from Take::read_(buf_)exact? Though this would "decouple" the limit from how many bytes are actually read, but that already happens if we do call into the inner reader and its read_exact fails, so 🤷.

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a1phyr commented Mar 14, 2024 •
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Perhaps self.limit should be set to 0 if Err(EOF) is returned from Take::read_(buf_)exact? Though this would "decouple" the limit from how many bytes are actually read, but that already happens if we do call into the inner reader and its read_exact fails, so 🤷.

I think that Take should never read more that limit bytes, whatever the circumstances, and decoupling seems wrong to me too. Only the default implementation feels correct, so I have removed Take::read_(buf_)exact from the PR.

One thing though, &[u8] and Cursor have this problem, so this should probably be changed in a follow-up PR.

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@a1phyr Can you split out the Unix-specific changes into their own PR?

@a1phyr a1phyr mentioned this pull request Mar 26, 2024
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workingjubilee added a commit to workingjubilee/rustc that referenced this pull request Mar 26, 2024
@workingjubilee
Rollup merge of rust-lang#123084 - a1phyr:unixstream_read_buf, r=work…
9bebf31 
…ingjubilee

`UnixStream`: override `read_buf`

Split from rust-lang#122441

r? `@workingjubilee`
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Mar 27, 2024
@matthiaskrgr
Rollup merge of rust-lang#123084 - a1phyr:unixstream_read_buf, r=work…
910e23b 
…ingjubilee

`UnixStream`: override `read_buf`

Split from rust-lang#122441

r? ``@workingjubilee``
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Mar 27, 2024
@rust-timer
Unrolled build for rust-lang#123084
edf466b 
Rollup merge of rust-lang#123084 - a1phyr:unixstream_read_buf, r=workingjubilee

`UnixStream`: override `read_buf`

Split from rust-lang#122441

r? ``@workingjubilee``
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bors commented Apr 10, 2024

☔ The latest upstream changes (presumably #122393) made this pull request unmergeable. Please resolve the merge conflicts.

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bors commented Apr 11, 2024

☔ The latest upstream changes (presumably #123732) made this pull request unmergeable. Please resolve the merge conflicts.

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lgtm. And thanks for @zachs18 for also reviewing!

@bors r+

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bors commented May 4, 2024

📌 Commit 2e3ee23 has been approved by ChrisDenton

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 4, 2024
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request May 4, 2024
@matthiaskrgr
Rollup merge of rust-lang#122441 - a1phyr:improve_read_impls, r=Chris…
76dc302 
…Denton

Improve several `Read` implementations

- `read_to_end` and `read_to_string` for `Cursor`
- Error on OOM in `read_to_string` of `&[u8]` and `VecDeque<u8>`
- Avoid making the slices contiguous in `VecDeque::read_to_string`
- ~`read_exact` and (unstable) `read_buf_exact` for `Take`~
- ~`read_buf` for `UnixStream` and `&UnixStream`~ (moved to rust-lang#123084)
- `read_to_end` for `ChildStdErr`
@matthiaskrgr matthiaskrgr mentioned this pull request May 4, 2024
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bors added a commit to rust-lang-ci/rust that referenced this pull request May 4, 2024
@bors
Auto merge of rust-lang#124710 - matthiaskrgr:rollup-per6u61, r=matth…
7852822 
…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#122441 (Improve several `Read` implementations)
 - rust-lang#124584 (Various improvements to entrypoint code)
 - rust-lang#124699 (Use `unchecked_sub` in `split_at`)
 - rust-lang#124704 (Fix ignored tests for formatting)
 - rust-lang#124709 (Miri subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup
bors added a commit to rust-lang-ci/rust that referenced this pull request May 4, 2024
@bors
Auto merge of rust-lang#124710 - matthiaskrgr:rollup-per6u61, r=matth…
8ea632f 
…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#122441 (Improve several `Read` implementations)
 - rust-lang#124584 (Various improvements to entrypoint code)
 - rust-lang#124699 (Use `unchecked_sub` in `split_at`)
 - rust-lang#124704 (Fix ignored tests for formatting)
 - rust-lang#124709 (Miri subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup
@matthiaskrgr matthiaskrgr mentioned this pull request May 4, 2024
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request May 4, 2024
@bors
Auto merge of rust-lang#124716 - matthiaskrgr:rollup-ni58ie1, r=matth…
d568423 
…iaskrgr

Rollup of 4 pull requests

Successful merges:

 - rust-lang#122441 (Improve several `Read` implementations)
 - rust-lang#124584 (Various improvements to entrypoint code)
 - rust-lang#124699 (Use `unchecked_sub` in `split_at`)
 - rust-lang#124715 (interpret, miri: uniform treatments of intrinsics/functions with and without return block)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 00bc2a4 into rust-lang:master May 4, 2024
11 checks passed
@rustbot rustbot added this to the 1.80.0 milestone May 4, 2024
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request May 4, 2024
@rust-timer
Unrolled build for rust-lang#122441
996721e 
Rollup merge of rust-lang#122441 - a1phyr:improve_read_impls, r=ChrisDenton

Improve several `Read` implementations

- `read_to_end` and `read_to_string` for `Cursor`
- Error on OOM in `read_to_string` of `&[u8]` and `VecDeque<u8>`
- Avoid making the slices contiguous in `VecDeque::read_to_string`
- ~`read_exact` and (unstable) `read_buf_exact` for `Take`~
- ~`read_buf` for `UnixStream` and `&UnixStream`~ (moved to rust-lang#123084)
- `read_to_end` for `ChildStdErr`
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