std: Stabilize parts of std::os::platform::io

This commit stabilizes the platform-specific `io` modules, specifically around
the traits having to do with the raw representation of each object on each
platform.

Specifically, the following material was stabilized:

* `AsRaw{Fd,Socket,Handle}`
* `RawFd` (renamed from `Fd`)
* `RawHandle` (renamed from `Handle`)
* `RawSocket` (renamed from `Socket`)
* `AsRaw{Fd,Socket,Handle}` implementations
* `std::os::{unix, windows}::io`

The following material was added as `#[unstable]`:

* `FromRaw{Fd,Socket,Handle}`
* Implementations for various primitives

There are a number of future improvements that are possible to make to this
module, but this should cover a good bit of functionality desired from these
modules for now. Some specific future additions may include:

* `IntoRawXXX` traits to consume the raw representation and cancel the
  auto-destructor.
* `Fd`, `Socket`, and `Handle` abstractions that behave like Rust objects and
  have nice methods for various syscalls.

At this time though, these are considered backwards-compatible extensions and
will not be stabilized at this time.

This commit is a breaking change due to the addition of `Raw` in from of the
type aliases in each of the platform-specific modules.

[breaking-change]

1 files changed, 9 insertions, 3 deletions

diff --git a/src/libstd/fs/mod.rs b/src/libstd/fs/mod.rs
index c1253706832..b01cb53388f 100644
--- a/src/libstd/fs/mod.rs
+++ b/src/libstd/fs/mod.rs
@@ -56,7 +56,7 @@ mod tempdir;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct File {
     inner: fs_imp::File,
-    path: PathBuf,
+    path: Option<PathBuf>,
 }
 
 /// Metadata information about a file.
@@ -171,7 +171,7 @@ impl File {
                reason = "this abstraction is imposed by this library instead \
                          of the underlying OS and may be removed")]
     pub fn path(&self) -> Option<&Path> {
-        Some(&self.path)
+        self.path.as_ref().map(|p| &**p)
     }
 
     /// Attempt to sync all OS-internal metadata to disk.
@@ -273,6 +273,12 @@ impl File {
 impl AsInner<fs_imp::File> for File {
     fn as_inner(&self) -> &fs_imp::File { &self.inner }
 }
+impl FromInner<fs_imp::File> for File {
+    fn from_inner(f: fs_imp::File) -> File {
+        File { inner: f, path: None }
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Read for File {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
@@ -381,7 +387,7 @@ impl OpenOptions {
     pub fn open<P: AsRef<Path>>(&self, path: P) -> io::Result<File> {
         let path = path.as_ref();
         let inner = try!(fs_imp::File::open(path, &self.0));
-        Ok(File { path: path.to_path_buf(), inner: inner })
+        Ok(File { path: Some(path.to_path_buf()), inner: inner })
     }
 }