Struct AtomicFileWriter 

pub struct AtomicFileWriter { /* private fields */ }

An atomic file writer that writes to a temporary file and renames on completion.

If the writer is dropped without calling finish(), the temporary file is removed (best-effort cleanup).

Implementations

impl AtomicFileWriter

pub fn new(dest: impl AsRef<Path>) -> Result<Self>

Create a new atomic writer targeting dest.

The temporary file is created with a random suffix in the same directory as dest, using O_CREAT | O_EXCL to prevent symlink-following attacks on shared filesystems.

Errors

Returns an I/O error if the temporary file cannot be created.

pub fn new_private(dest: impl AsRef<Path>) -> Result<Self>

Like new, but restricts the temp file (and therefore the renamed destination) to owner-read/write (0600) on Unix.

Use this when writing files that contain sensitive material such as plaintext secrets, so that the data is never world-readable — even during the brief window between the initial open and the rename.

Errors

Returns an error if the temporary file cannot be created or its permissions cannot be set.

pub fn finish(self) -> Result<()>

Flush all buffers, fsync, and atomically rename to the final destination.

Errors

Returns an I/O error if flush, sync, or rename fails. On error, the temporary file is cleaned up on a best-effort basis.

pub fn tmp_path(&self) -> &Path

Return the path of the temporary file (useful for cleanup on signal).

pub fn dest_path(&self) -> &Path

Return the final destination path.

Trait Implementations

impl Drop for AtomicFileWriter

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl Seek for AtomicFileWriter

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

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

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

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

Returns the current seek position from the start of the stream.

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.

impl Write for AtomicFileWriter

fn write(&mut self, buf: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.