Tracking Issue for `bufreader_peek`

[lolbinarycat]

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Feature gate: #![feature(bufreader_peek)]

This is a tracking issue for the BufReader::peek method.

Public API

// std::io

impl BufReader {
    fn peek(&mut self, n: usize) -> io::Result<&[u8]>
}

Steps / History

• ACP Accepted: ACP: BufReader::peek libs-team#417
• Implementation: implement BufReader::peek #128406
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• what should happen if n > capacity? options are: short slice, error, or panic.
• should the buffer be completely filled, or should it only read the number of bytes requested?

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[lolbinarycat]

@rustbot claim

starting work on implementation

[lolbinarycat]

calling peek should allow you to call consume with the same or a smaller n value. currently consume is only guaranteed to be well-behaved when calling it after fill_buf.