From 2cf686f2cdd6446a3cd47df0305ead40fabe85df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@thalheim.io>
Date: Sun, 26 Mar 2017 18:54:08 +0200
Subject: [PATCH] Implement AsRawFd/IntoRawFd for RawFd

This is useful to build os abstraction like the nix crate does.
It allows to define functions, which accepts generic arguments
of data structures convertible to RawFd, including RawFd itself.
For example:

  fn write<FD: AsRawFd>(fd: FD, buf: &[u8]) -> Result<usize>

instead of:

  fn write(fd: RawFd, buf: &[u8]) -> Result<usize>
  write(foo.as_raw_fd(), buf);
---
 src/libstd/sys/unix/ext/io.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/libstd/sys/unix/ext/io.rs b/src/libstd/sys/unix/ext/io.rs
index 296235e173d13..75aa72e3cff8c 100644
--- a/src/libstd/sys/unix/ext/io.rs
+++ b/src/libstd/sys/unix/ext/io.rs
@@ -72,6 +72,13 @@ pub trait IntoRawFd {
     fn into_raw_fd(self) -> RawFd;
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRawFd for RawFd {
+    fn as_raw_fd(&self) -> RawFd {
+        *self
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRawFd for fs::File {
     fn as_raw_fd(&self) -> RawFd {
@@ -84,6 +91,14 @@ impl FromRawFd for fs::File {
         fs::File::from_inner(sys::fs::File::from_inner(fd))
     }
 }
+
+#[stable(feature = "into_raw_os", since = "1.4.0")]
+impl IntoRawFd for RawFd {
+    fn into_raw_fd(self) -> RawFd {
+        self
+    }
+}
+
 #[stable(feature = "into_raw_os", since = "1.4.0")]
 impl IntoRawFd for fs::File {
     fn into_raw_fd(self) -> RawFd {