Struct ReadAtFiles 

pub struct ReadAtFiles { /* private fields */ }

Available on crate feature std only.

A regular file opened for ReadAt from many threads.

Windows serializes all reads on one handle, so there the file is opened several times (by default min(available_parallelism, 8)) and each thread sticks to one handle. Elsewhere one handle suffices.

On Windows the handles share read and delete access but not write access: a writer that opens the file in place fails, and the handles keep reading a file that was replaced or removed. Replacing it needs a rename that may replace an open file: MoveFileExW with MOVEFILE_REPLACE_EXISTING, which many runtimes use for their rename or move, fails with ERROR_ACCESS_DENIED while a handle is open. std::fs::rename then falls back to a POSIX semantics rename (NTFS, Windows 10 1809 and later), which works. With other tools, first rename the old file away, then the new one into place.

Implementations

impl ReadAtFiles

pub fn open(path: impl AsRef<Path>) -> Result<ReadAtFiles, Error>

Open path with the default number of handles for this platform.

Errors

Returns the I/O error of opening path, io::ErrorKind::InvalidInput if it is not a regular file, or io::ErrorKind::Other if the path kept naming different files while the handles were opened.

pub fn open_with_handles( path: impl AsRef<Path>, handles: NonZero<usize>, ) -> Result<ReadAtFiles, Error>

Open path with handles handles.

Errors

Same as Self::open.

pub fn identity(&self) -> FileIdentity

The identity of the file, taken from the first handle when it was opened.

pub fn handles(&self) -> usize

The number of open handles.

Trait Implementations

impl Debug for ReadAtFiles

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl ReadAt for ReadAtFiles

fn read_exact_at(&self, buf: &mut [u8], offset: u64) -> Result<(), Error>

Fill all of buf with the bytes starting at offset.

fn size(&self) -> Result<u64, Error>

The current size of the source in bytes.