What it does

Suggest using StdinLock rather than BufReader::new(io::stdin()) since it is already buffered. We might also want to take care of let stdin = io::stdin(); BufReader::new(stdin) and also BufReader::new(stdinlock) (there could be people doing this).

Categories (optional)

• Kind: perf

Locking stdin also provide benefit for not having to re-lock it on every read.

std::io::stdin() already is buffered. Re-buffering it only increase the memcpy calls.

Source https://users.rust-lang.org/t/correct-way-for-taking-large-input-from-keyboard/55304/11
Related to #1805

For example:

• Recommend locking of stdin to reduce re-locking
• Suggest not re-buffering stdin lock which already implements BufRead

Drawbacks

None.

Example

let reader = BufReader::new(io::stdin());  // this could a separate variable or StdinLock

Could be written as:

let stdin = io::stdin();
let reader = stdin.lock();