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//! The following is derived from Rust's
//! library/std/src/os/fd/raw.rs at revision
//! fa68e73e9947be8ffc5b3b46d899e4953a44e7e9.
//!
//! Raw Unix-like file descriptors.
#![cfg_attr(staged_api, stable(feature = "rust1", since = "1.0.0"))]
#![allow(unsafe_code)]
use crate::imp::c;
/// Raw file descriptors.
#[cfg_attr(staged_api, stable(feature = "rust1", since = "1.0.0"))]
pub type RawFd = c::c_int;
/// A trait to extract the raw file descriptor from an underlying object.
///
/// This is only available on unix and WASI platforms and must be imported in
/// order to call the method. Windows platforms have a corresponding
/// `AsRawHandle` and `AsRawSocket` set of traits.
#[cfg_attr(staged_api, stable(feature = "rust1", since = "1.0.0"))]
pub trait AsRawFd {
/// Extracts the raw file descriptor.
///
/// This function is typically used to **borrow** an owned file descriptor.
/// When used in this way, this method does **not** pass ownership of the
/// raw file descriptor to the caller, and the file descriptor is only
/// guaranteed to be valid while the original object has not yet been
/// destroyed.
///
/// However, borrowing is not strictly required. See [`AsFd::as_fd`]
/// for an API which strictly borrows a file descriptor.
///
/// # Example
///
/// ```no_run
/// use std::fs::File;
/// # use std::io;
/// #[cfg(unix)]
/// use std::os::unix::io::{AsRawFd, RawFd};
/// #[cfg(target_os = "wasi")]
/// use std::os::wasi::io::{AsRawFd, RawFd};
///
/// let mut f = File::open("foo.txt")?;
/// // `raw_fd` is only valid as long as `f` exists.
/// #[cfg(any(unix, target_os = "wasi"))]
/// let raw_fd: RawFd = f.as_raw_fd();
/// # Ok::<(), io::Error>(())
/// ```
#[cfg_attr(staged_api, stable(feature = "rust1", since = "1.0.0"))]
fn as_raw_fd(&self) -> RawFd;
}
/// A trait to express the ability to construct an object from a raw file
/// descriptor.
#[cfg_attr(staged_api, stable(feature = "from_raw_os", since = "1.1.0"))]
pub trait FromRawFd {
/// Constructs a new instance of `Self` from the given raw file
/// descriptor.
///
/// This function is typically used to **consume ownership** of the
/// specified file descriptor. When used in this way, the returned object
/// will take responsibility for closing it when the object goes out of
/// scope.
///
/// However, consuming ownership is not strictly required. Use a
/// [`From<OwnedFd>::from`] implementation for an API which strictly
/// consumes ownership.
///
/// # Safety
///
/// The `fd` passed in must be a valid an open file descriptor.
///
/// # Example
///
/// ```no_run
/// use std::fs::File;
/// # use std::io;
/// #[cfg(unix)]
/// use std::os::unix::io::{FromRawFd, IntoRawFd, RawFd};
/// #[cfg(target_os = "wasi")]
/// use std::os::wasi::io::{FromRawFd, IntoRawFd, RawFd};
///
/// let f = File::open("foo.txt")?;
/// # #[cfg(any(unix, target_os = "wasi"))]
/// let raw_fd: RawFd = f.into_raw_fd();
/// // SAFETY: no other functions should call `from_raw_fd`, so there
/// // is only one owner for the file descriptor.
/// # #[cfg(any(unix, target_os = "wasi"))]
/// let f = unsafe { File::from_raw_fd(raw_fd) };
/// # Ok::<(), io::Error>(())
/// ```
#[cfg_attr(staged_api, stable(feature = "from_raw_os", since = "1.1.0"))]
unsafe fn from_raw_fd(fd: RawFd) -> Self;
}
/// A trait to express the ability to consume an object and acquire ownership of
/// its raw file descriptor.
#[cfg_attr(staged_api, stable(feature = "into_raw_os", since = "1.4.0"))]
pub trait IntoRawFd {
/// Consumes this object, returning the raw underlying file descriptor.
///
/// This function is typically used to **transfer ownership** of the underlying
/// file descriptor to the caller. When used in this way, callers are then the unique
/// owners of the file descriptor and must close it once it's no longer needed.
///
/// However, transferring ownership is not strictly required. Use a
/// [`Into<OwnedFd>::into`] implementation for an API which strictly
/// transfers ownership.
///
/// # Example
///
/// ```no_run
/// use std::fs::File;
/// # use std::io;
/// #[cfg(unix)]
/// use std::os::unix::io::{IntoRawFd, RawFd};
/// #[cfg(target_os = "wasi")]
/// use std::os::wasi::io::{IntoRawFd, RawFd};
///
/// let f = File::open("foo.txt")?;
/// #[cfg(any(unix, target_os = "wasi"))]
/// let raw_fd: RawFd = f.into_raw_fd();
/// # Ok::<(), io::Error>(())
/// ```
#[cfg_attr(staged_api, stable(feature = "into_raw_os", since = "1.4.0"))]
fn into_raw_fd(self) -> RawFd;
}
#[cfg_attr(
staged_api,
stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")
)]
impl AsRawFd for RawFd {
#[inline]
fn as_raw_fd(&self) -> RawFd {
*self
}
}
#[cfg_attr(
staged_api,
stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")
)]
impl IntoRawFd for RawFd {
#[inline]
fn into_raw_fd(self) -> RawFd {
self
}
}
#[cfg_attr(
staged_api,
stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")
)]
impl FromRawFd for RawFd {
#[inline]
unsafe fn from_raw_fd(fd: RawFd) -> RawFd {
fd
}
}
|
