Struct File

pub struct File { /* private fields */ }

A reference to an open file on a filesystem.

This corresponds to std::fs::File.

This File has no open or create methods. To open or create a file, first obtain a Dir containing the path, and then call Dir::open or Dir::create.

Implementations

impl File

pub fn from_std(std: File) -> Self

Constructs a new instance of Self from the given std::fs::File.

This grants access the resources the std::fs::File instance already has access to.

pub fn into_std(self) -> File

Consumes self and returns a std::fs::File.

pub fn sync_all(&self) -> Result<()>

Attempts to sync all OS-internal metadata to disk.

This corresponds to std::fs::File::sync_all.

pub fn sync_data(&self) -> Result<()>

This function is similar to sync_all, except that it may not synchronize file metadata to a filesystem.

This corresponds to std::fs::File::sync_data.

pub fn set_len(&self, size: u64) -> Result<()>

Truncates or extends the underlying file, updating the size of this file to become size.

This corresponds to std::fs::File::set_len.

pub fn metadata(&self) -> Result<Metadata>

Queries metadata about the underlying file.

This corresponds to std::fs::File::metadata.

pub fn try_clone(&self) -> Result<Self>

Creates a new File instance that shares the same underlying file handle as the existing File instance.

This corresponds to std::fs::File::try_clone.

pub fn set_permissions(&self, perm: Permissions) -> Result<()>

Changes the permissions on the underlying file.

This corresponds to std::fs::File::set_permissions.

pub fn open_ambient<P: AsRef<Path>>( path: P, ambient_authority: AmbientAuthority, ) -> Result<Self>

Constructs a new instance of Self in read-only mode by opening the given path as a file using the host process’ ambient authority.

Ambient Authority

This function is not sandboxed and may access any path that the host process has access to.

pub fn create_ambient<P: AsRef<Path>>( path: P, ambient_authority: AmbientAuthority, ) -> Result<Self>

Constructs a new instance of Self in write-only mode by opening, creating or truncating, the given path as a file using the host process’ ambient authority.

Ambient Authority

This function is not sandboxed and may access any path that the host process has access to.

pub fn open_ambient_with<P: AsRef<Path>>( path: P, options: &OpenOptions, ambient_authority: AmbientAuthority, ) -> Result<Self>

Constructs a new instance of Self with the options specified by options by opening the given path as a file using the host process’ ambient authority.

Ambient Authority

This function is not sandboxed and may access any path that the host process has access to.

pub fn options() -> OpenOptions

Returns a new OpenOptions object.

This corresponds to std::fs::File::options.

Trait Implementations

impl AsFd for File

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor.

impl AsRawFd for File

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for File

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

Formats the value using the given formatter.

impl FileExt for File

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

Reads a number of bytes starting from a given offset.

fn write_at(&self, buf: &[u8], offset: u64) -> Result<usize>

Writes a number of bytes starting from a given offset.

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

Reads the exact number of bytes required to fill buf from the given offset.

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

Attempts to write an entire buffer starting from a given offset.

impl From<File> for OwnedFd

fn from(file: File) -> OwnedFd

Converts to this type from the input type.

impl From<File> for Stdio

fn from(file: File) -> Self

Converts to this type from the input type.

impl From<OwnedFd> for File

fn from(fd: OwnedFd) -> Self

Converts to this type from the input type.

impl FromRawFd for File

unsafe fn from_raw_fd(fd: RawFd) -> Self

Constructs a new instance of Self from the given raw file descriptor.

impl IntoRawFd for File

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.

impl Read for &File

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>

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

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

Reads the exact number of bytes required to fill buf.

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

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

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

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

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_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 Read for File

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>

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

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

Reads the exact number of bytes required to fill buf.

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

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

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

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

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_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 Seek for &File

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

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

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

Returns the current seek position from the start of the 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 seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.

impl Seek for File

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

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

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

Returns the current seek position from the start of the 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 seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.

impl Write for &File

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>

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

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

Attempts to write an entire buffer into this writer.

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_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.

impl Write for File

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>

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

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

Attempts to write an entire buffer into this writer.

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_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.

impl FilelikeViewType for File