Struct TempFile

pub struct TempFile<'d> { /* private fields */ }

A file in a directory that is by default deleted when it goes out of scope, but may also be written persistently.

This corresponds most closely to tempfile::NamedTempFile; however, there are some important differences, so read the below carefully to understand how to port existing code.

Name-able, but not necessarily named

By default, the file does not necessarily have an name until the file is written persistently.

On some operating systems like Linux, it is possible to create anonymous temporary files that can still be written to disk persistently via O_TMPFILE. The advantage of this is that if the process (or operating system) crashes while the file is being written, the temporary space will be automatically cleaned up. For this reason, there is no API to retrieve the name, for either case.

To more closely match the semantics of tempfile::tempfile, use crate::TempFile::new_anonymous.

File permissions

Unlike the tempfile crate, the default TempFile::new will use the same permissions as File::create_new in the Rust standard library. Concretely on Unix systems for example this can (depending on umask) result in files that are readable by all users. The rationale for this is to make it more ergonomic and natural to use this API to atomically create new files and replace existing ones. Many cases that want “private” files will prefer TempFile::new_anonymous to have the file not be accessible at all outside the current process.

To fully control the permissions of the resulting file, you can use File::set_permissions.

Implementations

impl<'d> TempFile<'d>

pub fn new(dir: &'d Dir) -> Result<Self>

Crate a new temporary file in the provided directory.

pub fn new_anonymous(dir: &'d Dir) -> Result<File>

Crate a new temporary file in the provided directory that will not have a name. This corresponds to tempfile::tempfile_in.

pub fn as_file(&self) -> &File

Get a reference to the underlying file.

pub fn as_file_mut(&mut self) -> &mut File

Get a mutable reference to the underlying file.

pub fn replace(self, destname: impl AsRef<OsStr>) -> Result<()>

Write the file to the target directory with the provided name. Any existing file will be replaced.

The file permissions will default to read-only.

Trait Implementations

impl<'d> Debug for TempFile<'d>

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

Formats the value using the given formatter.

impl<'d> Drop for TempFile<'d>

fn drop(&mut self)

Executes the destructor for this type.

impl<'d> Read for TempFile<'d>

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

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

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

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

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

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

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

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

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

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

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

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl<'d> Seek for TempFile<'d>

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<'d> Write for TempFile<'d>

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, fmt: 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.