libs: add std::os::unix module

The new `std::os::unix` module exposes several extension traits
for extracting file descriptors from `std::io` types.

src/libstd/sys/unix/ext.rs

@@ -0,0 +1,107 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Experimental extensions to `std` for Unix platforms.
+//!
+//! For now, this module is limited to extracting file descriptors,
+//! but its functionality will grow over time.
+//!
+//! # Example
+//!
+//! ```rust,ignore
+//! #![feature(globs)]
+//!
+//! use std::io::fs::File;
+//! use std::os::unix::prelude::*;
+//!
+//! fn main() {
+//!     let f = File::create(&Path::new("foo.txt")).unwrap();
+//!     let fd = f.as_raw_fd();
+//!
+//!     // use fd with native unix bindings
+//! }
+//! ```
+
+#![experimental]
+
+use sys_common::AsInner;
+use libc;
+
+use io;
+
+/// Raw file descriptors.
+pub type Fd = libc::c_int;
+
+/// Extract raw file descriptor
+pub trait AsRawFd {
+    /// Extract the raw file descriptor, without taking any ownership.
+    fn as_raw_fd(&self) -> Fd;
+}
+
+impl AsRawFd for io::fs::File {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::pipe::PipeStream {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::pipe::UnixStream {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::pipe::UnixListener {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::pipe::UnixAcceptor {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::tcp::TcpStream {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::tcp::TcpListener {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::tcp::TcpAcceptor {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+impl AsRawFd for io::net::udp::UdpSocket {
+    fn as_raw_fd(&self) -> Fd {
+        self.as_inner().fd()
+    }
+}
+
+/// A prelude for conveniently writing platform-specific code.
+///
+/// Includes all extension traits, and some important type definitions.
+pub mod prelude {
+    pub use super::{Fd, AsRawFd};
+}

src/libstd/sys/unix/mod.rs

@@ -33,6 +33,7 @@ macro_rules! helper_init( (static $name:ident: Helper<$m:ty>) => (
 ) )
 
 pub mod c;
+pub mod ext;
 pub mod fs;
 pub mod os;
 pub mod tcp;