mirror of
https://github.com/rust-lang/rust.git
synced 2025-01-28 15:43:21 +00:00
caf8bcceff
Add a `is_known_utf8` flag to `Wtf8Buf`, which tracks whether the string is known to contain UTF-8. This is efficiently computed in many common situations, such as when a `Wtf8Buf` is constructed from a `String` or `&str`, or with `Wtf8Buf::from_wide` which is already doing UTF-16 decoding and already checking for surrogates. This makes `OsString::into_string` O(1) rather than O(N) on Windows in common cases. And, it eliminates the need to scan through the string for surrogates in `Args::next` and `Vars::next`, because the strings are already being translated with `Wtf8Buf::from_wide`. Many things on Windows construct `OsString`s with `Wtf8Buf::from_wide`, such as `DirEntry::file_name` and `fs::read_link`, so with this patch, users of those functions can subsequently call `.into_string()` without paying for an extra scan through the string for surrogates. |
||
|---|---|---|
| .. | ||
| alloc | ||
| backtrace@4e5a3f7292 | ||
| core | ||
| panic_abort | ||
| panic_unwind | ||
| portable-simd | ||
| proc_macro | ||
| profiler_builtins | ||
| rtstartup | ||
| rustc-std-workspace-alloc | ||
| rustc-std-workspace-core | ||
| rustc-std-workspace-std | ||
| std | ||
| stdarch@28335054b1 | ||
| test | ||
| unwind | ||