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-rw-r--r--library/std/src/os/fd/raw.rs259
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diff --git a/library/std/src/os/fd/raw.rs b/library/std/src/os/fd/raw.rs
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+//! Raw Unix-like file descriptors.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use crate::fs;
+use crate::io;
+use crate::os::raw;
+#[cfg(all(doc, not(target_arch = "wasm32")))]
+use crate::os::unix::io::AsFd;
+#[cfg(unix)]
+use crate::os::unix::io::OwnedFd;
+#[cfg(target_os = "wasi")]
+use crate::os::wasi::io::OwnedFd;
+use crate::sys_common::{AsInner, IntoInner};
+
+/// Raw file descriptors.
+#[cfg_attr(not(bootstrap), rustc_allowed_through_unstable_modules)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type RawFd = raw::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(not(bootstrap), rustc_allowed_through_unstable_modules)]
+#[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")?;
+ /// // Note that `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>(())
+ /// ```
+ #[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(not(bootstrap), rustc_allowed_through_unstable_modules)]
+#[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 and 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>(())
+ /// ```
+ #[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(not(bootstrap), rustc_allowed_through_unstable_modules)]
+#[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>(())
+ /// ```
+ #[stable(feature = "into_raw_os", since = "1.4.0")]
+ fn into_raw_fd(self) -> RawFd;
+}
+
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl AsRawFd for RawFd {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ *self
+ }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl IntoRawFd for RawFd {
+ #[inline]
+ fn into_raw_fd(self) -> RawFd {
+ self
+ }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl FromRawFd for RawFd {
+ #[inline]
+ unsafe fn from_raw_fd(fd: RawFd) -> RawFd {
+ fd
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRawFd for fs::File {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ self.as_inner().as_raw_fd()
+ }
+}
+#[stable(feature = "from_raw_os", since = "1.1.0")]
+impl FromRawFd for fs::File {
+ #[inline]
+ unsafe fn from_raw_fd(fd: RawFd) -> fs::File {
+ unsafe { fs::File::from(OwnedFd::from_raw_fd(fd)) }
+ }
+}
+#[stable(feature = "into_raw_os", since = "1.4.0")]
+impl IntoRawFd for fs::File {
+ #[inline]
+ fn into_raw_fd(self) -> RawFd {
+ self.into_inner().into_inner().into_raw_fd()
+ }
+}
+
+#[stable(feature = "asraw_stdio", since = "1.21.0")]
+impl AsRawFd for io::Stdin {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ libc::STDIN_FILENO
+ }
+}
+
+#[stable(feature = "asraw_stdio", since = "1.21.0")]
+impl AsRawFd for io::Stdout {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ libc::STDOUT_FILENO
+ }
+}
+
+#[stable(feature = "asraw_stdio", since = "1.21.0")]
+impl AsRawFd for io::Stderr {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ libc::STDERR_FILENO
+ }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdinLock<'a> {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ libc::STDIN_FILENO
+ }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdoutLock<'a> {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ libc::STDOUT_FILENO
+ }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StderrLock<'a> {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ libc::STDERR_FILENO
+ }
+}
+
+/// This impl allows implementing traits that require `AsRawFd` on Arc.
+/// ```
+/// # #[cfg(any(unix, target_os = "wasi"))] mod group_cfg {
+/// # #[cfg(target_os = "wasi")]
+/// # use std::os::wasi::io::AsRawFd;
+/// # #[cfg(unix)]
+/// # use std::os::unix::io::AsRawFd;
+/// use std::net::UdpSocket;
+/// use std::sync::Arc;
+/// trait MyTrait: AsRawFd {
+/// }
+/// impl MyTrait for Arc<UdpSocket> {}
+/// impl MyTrait for Box<UdpSocket> {}
+/// # }
+/// ```
+#[stable(feature = "asrawfd_ptrs", since = "1.63.0")]
+impl<T: AsRawFd> AsRawFd for crate::sync::Arc<T> {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ (**self).as_raw_fd()
+ }
+}
+
+#[stable(feature = "asrawfd_ptrs", since = "1.63.0")]
+impl<T: AsRawFd> AsRawFd for Box<T> {
+ #[inline]
+ fn as_raw_fd(&self) -> RawFd {
+ (**self).as_raw_fd()
+ }
+}
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