Struct FileDescriptor

pub struct FileDescriptor { /* private fields */ }

FileDescriptor is a thin wrapper on top of the OwnedHandle type that exposes the ability to Read and Write to the platform RawFileDescriptor.

This is a bit of a contrived example, but demonstrates how to avoid the conditional code that would otherwise be required to deal with calling as_raw_fd and as_raw_handle:

use filedescriptor::{FileDescriptor, FromRawFileDescriptor, Result};
use std::io::Write;

fn get_stdout() -> Result<FileDescriptor> {
  let stdout = std::io::stdout();
  let handle = stdout.lock();
  FileDescriptor::dup(&handle)
}

fn print_something() -> Result<()> {
   get_stdout()?.write(b"hello")?;
   Ok(())
}

Implementations

impl FileDescriptor

pub unsafe fn dup2<F>(f: &F, dest_fd: i32) -> Result<FileDescriptor, Error>

where F: AsRawFileDescriptor,

Attempt to duplicate the underlying handle from an object that is representable as the system RawFileDescriptor type and assign it to a destination file descriptor. It then returns a FileDescriptor wrapped around the duplicate. Since the duplication requires kernel resources that may not be available, this is a potentially fallible operation. The returned handle has a separate lifetime from the source, but references the same object at the kernel level.

impl FileDescriptor

pub fn new<F>(f: F) -> FileDescriptor

where F: IntoRawFileDescriptor,

Create a new descriptor from some object that is convertible into the system RawFileDescriptor type. This consumes the parameter and replaces it with a FileDescriptor instance.

pub fn dup<F>(f: &F) -> Result<FileDescriptor, Error>

where F: AsRawFileDescriptor,

Attempt to duplicate the underlying handle from an object that is representable as the system RawFileDescriptor type and return a FileDescriptor wrapped around the duplicate. Since the duplication requires kernel resources that may not be available, this is a potentially fallible operation. The returned handle has a separate lifetime from the source, but references the same object at the kernel level.

pub fn try_clone(&self) -> Result<FileDescriptor, Error>

Attempt to duplicate the underlying handle and return a FileDescriptor wrapped around the duplicate. Since the duplication requires kernel resources that may not be available, this is a potentially fallible operation. The returned handle has a separate lifetime from the source, but references the same object at the kernel level.

pub fn as_stdio(&self) -> Result<Stdio, Error>

A convenience method for creating a std::process::Stdio object to be used for eg: redirecting the stdio streams of a child process. The Stdio is created using a duplicated handle so that the source handle remains alive.

pub fn as_file(&self) -> Result<File, Error>

A convenience method for creating a std::fs::File object. The File is created using a duplicated handle so that the source handle remains alive.

pub fn set_non_blocking(&mut self, non_blocking: bool) -> Result<(), Error>

Attempt to change the non-blocking IO mode of the file descriptor. Not all kinds of file descriptor can be placed in non-blocking mode on all systems, and some file descriptors will claim to be in non-blocking mode but it will have no effect. File descriptors based on sockets are the most portable type that can be successfully made non-blocking.

pub fn redirect_stdio<F>( f: &F, stdio: StdioDescriptor, ) -> Result<FileDescriptor, Error>

where F: AsRawFileDescriptor,

Attempt to redirect stdio to the underlying handle and return a FileDescriptor wrapped around the original stdio source. Since the redirection requires kernel resources that may not be available, this is a potentially fallible operation. Supports stdin, stdout, and stderr redirections.

Trait Implementations

impl AsFd for FileDescriptor

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

Borrows the file descriptor.

impl AsRawFd for FileDescriptor

fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor.

impl Debug for FileDescriptor

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

Formats the value using the given formatter.

impl FromRawFd for FileDescriptor

unsafe fn from_raw_fd(fd: i32) -> FileDescriptor

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

impl IntoRawFd for FileDescriptor

fn into_raw_fd(self) -> i32

Consumes this object, returning the raw underlying file descriptor.

impl Read for FileDescriptor

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

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 Write for FileDescriptor

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

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

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

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.