impl Send for DirIter
#42
Open
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This will allow using `DirIter` with rayon's `par_bridge`. It may not be thread-safe to call readdir concurrently from multiple threads on a single `DIR*`, but all `Send` requires is that we can call it from different threads non-concurrently - so this is fine. `man readdir` says: > It is expected that a future version of POSIX.1 will require that > `readdir()` be thread-safe when concurrently employed on different > directory streams. so in the future we may also be able to implement `Sync`. The `std` implements both `Send` and `Sync` on [`ReadDir`], but they implement iteration using the deprecated [`readdir_r`]. To be sure I've also looked at the implementation of readdir on [glibc], [musl] and [freebsd] and they all use per `struct DIR` allocations for the dirent buffer. [`ReadDir`]: https://github.com/rust-lang/rust/blob/7e11f3a8f3c1b2683125e7def0acb68a6d684f92/library/std/src/sys/unix/fs.rs#L478-L511 [`readdir_r`]: https://man7.org/linux/man-pages/man3/readdir_r.3.html [glibc]: https://code.woboq.org/userspace/glibc/sysdeps/posix/readdir.c.html [musl]: https://git.musl-libc.org/cgit/musl/tree/src/dirent/readdir.c [freebsd]: https://github.com/freebsd/freebsd-src/blob/373ffc62c158e52cde86a5b934ab4a51307f9f2e/lib/libc/gen/opendir.c#L337
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This will allow using
DirIterwith rayon'spar_bridge.It may not be thread-safe to call readdir concurrently from multiple
threads on a single
DIR*, but allSendrequires is that we can callit from different threads non-concurrently - so this is fine.
man readdirsays:so in the future we may also be able to implement
Sync. Thestdimplements both
SendandSynconReadDir, but they implementiteration using the deprecated
readdir_r.To be sure I've also looked at the implementation of readdir on glibc,
musl and freebsd and they all use per
struct DIRallocations forthe dirent buffer.