Implement I/O-safe traits on Socket

Cargo.toml

@@ -46,4 +46,4 @@ features = [
 
 [features]
 # Enable all API, even ones not available on all OSs.
-all = []
+all = []

src/sys/unix.rs

@@ -37,7 +37,7 @@ use std::os::unix::ffi::OsStrExt;
     )
 ))]
 use std::os::unix::io::RawFd;
-use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd};
+use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd};
 #[cfg(feature = "all")]
 use std::os::unix::net::{UnixDatagram, UnixListener, UnixStream};
 #[cfg(feature = "all")]
@@ -2031,6 +2031,29 @@ impl FromRawFd for crate::Socket {
     }
 }
 
+#[cfg_attr(docsrs, doc(cfg(unix)))]
+impl AsFd for crate::Socket {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        // SAFETY: lifetime is bound by "self"
+        unsafe { BorrowedFd::borrow_raw(self.as_raw()) }
+    }
+}
+
+#[cfg_attr(docsrs, doc(cfg(unix)))]
+impl From<OwnedFd> for crate::Socket {
+    fn from(fd: OwnedFd) -> Self {
+        Self::from_raw(fd.into_raw_fd())
+    }
+}
+
+#[cfg_attr(docsrs, doc(cfg(unix)))]
+impl From<crate::Socket> for OwnedFd {
+    fn from(sock: crate::Socket) -> Self {
+        // SAFETY: sock.into_raw() is a valid fd
+        unsafe { OwnedFd::from_raw_fd(sock.into_raw()) }
+    }
+}
+
 #[cfg(feature = "all")]
 from!(UnixStream, crate::Socket);
 #[cfg(feature = "all")]

src/sys/windows.rs

@@ -11,7 +11,9 @@ use std::io::{self, IoSlice};
 use std::marker::PhantomData;
 use std::mem::{self, size_of, MaybeUninit};
 use std::net::{self, Ipv4Addr, Ipv6Addr, Shutdown};
-use std::os::windows::io::{AsRawSocket, FromRawSocket, IntoRawSocket, RawSocket};
+use std::os::windows::io::{
+    AsRawSocket, AsSocket, BorrowedSocket, FromRawSocket, IntoRawSocket, OwnedSocket, RawSocket,
+};
 use std::sync::Once;
 use std::time::{Duration, Instant};
 use std::{process, ptr, slice};
@@ -818,6 +820,26 @@ impl FromRawSocket for crate::Socket {
     }
 }
 
+impl AsSocket for crate::Socket {
+    fn as_socket(&self) -> BorrowedSocket<'_> {
+        // SAFETY: lifetime is bound by "self"
+        unsafe { BorrowedSocket::borrow_raw(self.as_raw() as RawSocket) }
+    }
+}
+
+impl From<OwnedSocket> for crate::Socket {
+    fn from(fd: OwnedSocket) -> Self {
+        Self::from_raw(fd.into_raw_socket() as Socket)
+    }
+}
+
+impl From<crate::Socket> for OwnedSocket {
+    fn from(sock: crate::Socket) -> Self {
+        // SAFETY: sock.into_raw() is a valid fd
+        unsafe { OwnedSocket::from_raw_socket(sock.into_raw() as RawSocket) }
+    }
+}
+
 #[test]
 fn in_addr_convertion() {
     let ip = Ipv4Addr::new(127, 0, 0, 1);