Stabilize std::convert and related code

* Marks `#[stable]` the contents of the `std::convert` module.

* Added methods `PathBuf::as_path`, `OsString::as_os_str`,
  `String::as_str`, `Vec::{as_slice, as_mut_slice}`.

* Deprecates `OsStr::from_str` in favor of a new, stable, and more
  general `OsStr::new`.

* Adds unstable methods `OsString::from_bytes` and `OsStr::{to_bytes,
  to_cstring}` for ergonomic FFI usage.

[breaking-change]

src/compiletest/compiletest.rs

@@ -18,7 +18,6 @@
 #![feature(std_misc)]
 #![feature(test)]
 #![feature(path_ext)]
-#![feature(convert)]
 #![feature(str_char)]
 
 #![deny(warnings)]

src/libcollections/lib.rs

@@ -38,7 +38,6 @@
 #![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(step_by)]
 #![feature(str_char)]
-#![feature(convert)]
 #![feature(slice_patterns)]
 #![feature(debug_builders)]
 #![cfg_attr(test, feature(rand, rustc_private, test, hash, collections))]

src/libcollections/string.rs

@@ -364,6 +364,14 @@ impl String {
         self.vec
     }
 
+    /// Extract a string slice containing the entire string.
+    #[inline]
+    #[unstable(feature = "convert",
+               reason = "waiting on RFC revision")]
+    pub fn as_str(&self) -> &str {
+        self
+    }
+
     /// Pushes the given string onto this string buffer.
     ///
     /// # Examples
@@ -848,7 +856,6 @@ impl<'a, 'b> PartialEq<Cow<'a, str>> for &'b str {
 #[allow(deprecated)]
 impl Str for String {
     #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
     fn as_slice(&self) -> &str {
         unsafe { mem::transmute(&*self.vec) }
     }

src/libcollections/vec.rs

@@ -423,11 +423,18 @@ impl<T> Vec<T> {
         }
     }
 
+    /// Extract a slice containing the entire vector.
+    #[inline]
+    #[unstable(feature = "convert",
+               reason = "waiting on RFC revision")]
+    pub fn as_slice(&self) -> &[T] {
+        self
+    }
+
     /// Deprecated: use `&mut s[..]` instead.
     #[inline]
-    #[unstable(feature = "collections",
-               reason = "will be replaced by slice syntax")]
-    #[deprecated(since = "1.0.0", reason = "use &mut s[..] instead")]
+    #[unstable(feature = "convert",
+               reason = "waiting on RFC revision")]
     pub fn as_mut_slice(&mut self) -> &mut [T] {
         &mut self[..]
     }
@@ -1640,13 +1647,6 @@ impl<T> AsRef<Vec<T>> for Vec<T> {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T> Into<Vec<T>> for Vec<T> {
-    fn into(self) -> Vec<T> {
-        self
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsRef<[T]> for Vec<T> {
     fn as_ref(&self) -> &[T] {

src/libcore/convert.rs

@@ -14,33 +14,40 @@
 //! conversions from one type to another. They follow the standard
 //! Rust conventions of `as`/`to`/`into`/`from`.
 
-#![unstable(feature = "convert",
-            reason = "recently added, experimental traits")]
+#![stable(feature = "rust1", since = "1.0.0")]
 
 use marker::Sized;
 
 /// A cheap, reference-to-reference conversion.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsRef<T: ?Sized> {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn as_ref(&self) -> &T;
 }
 
 /// A cheap, mutable reference-to-mutable reference conversion.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsMut<T: ?Sized> {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn as_mut(&mut self) -> &mut T;
 }
 
 /// A conversion that consumes `self`, which may or may not be
 /// expensive.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait Into<T>: Sized {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn into(self) -> T;
 }
 
 /// Construct `Self` via a conversion.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait From<T> {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn from(T) -> Self;
 }
 
@@ -48,14 +55,8 @@ pub trait From<T> {
 // GENERIC IMPLS
 ////////////////////////////////////////////////////////////////////////////////
 
-// As implies Into
-impl<'a, T: ?Sized, U: ?Sized> Into<&'a U> for &'a T where T: AsRef<U> {
-    fn into(self) -> &'a U {
-        self.as_ref()
-    }
-}
-
 // As lifts over &
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a T where T: AsRef<U> {
     fn as_ref(&self) -> &U {
         <T as AsRef<U>>::as_ref(*self)
@@ -63,6 +64,7 @@ impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a T where T: AsRef<U> {
 }
 
 // As lifts over &mut
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a mut T where T: AsRef<U> {
     fn as_ref(&self) -> &U {
         <T as AsRef<U>>::as_ref(*self)
@@ -77,14 +79,8 @@ impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a mut T where T: AsRef<U> {
 //     }
 // }
 
-// AsMut implies Into
-impl<'a, T: ?Sized, U: ?Sized> Into<&'a mut U> for &'a mut T where T: AsMut<U> {
-    fn into(self) -> &'a mut U {
-        (*self).as_mut()
-    }
-}
-
 // AsMut lifts over &mut
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized, U: ?Sized> AsMut<U> for &'a mut T where T: AsMut<U> {
     fn as_mut(&mut self) -> &mut U {
         (*self).as_mut()
@@ -100,28 +96,38 @@ impl<'a, T: ?Sized, U: ?Sized> AsMut<U> for &'a mut T where T: AsMut<U> {
 // }
 
 // From implies Into
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T, U> Into<U> for T where U: From<T> {
     fn into(self) -> U {
         U::from(self)
     }
 }
 
+// From (and thus Into) is reflexive
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> From<T> for T {
+    fn from(t: T) -> T { t }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // CONCRETE IMPLS
 ////////////////////////////////////////////////////////////////////////////////
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsRef<[T]> for [T] {
     fn as_ref(&self) -> &[T] {
         self
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsMut<[T]> for [T] {
     fn as_mut(&mut self) -> &mut [T] {
         self
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for str {
     fn as_ref(&self) -> &str {
         self

src/librustc/lib.rs

@@ -41,7 +41,6 @@
 #![feature(path_ext)]
 #![feature(str_words)]
 #![feature(str_char)]
-#![feature(convert)]
 #![feature(into_cow)]
 #![feature(slice_patterns)]
 #![cfg_attr(test, feature(test))]

src/librustc_back/lib.rs

@@ -46,7 +46,6 @@
 #![feature(path_ext)]
 #![feature(std_misc)]
 #![feature(step_by)]
-#![feature(convert)]
 #![cfg_attr(test, feature(test, rand))]
 
 extern crate syntax;

src/librustc_driver/lib.rs

@@ -38,7 +38,6 @@
 #![feature(io)]
 #![feature(set_stdio)]
 #![feature(unicode)]
-#![feature(convert)]
 
 extern crate arena;
 extern crate flate;

src/librustc_trans/lib.rs

@@ -39,7 +39,6 @@
 #![feature(unicode)]
 #![feature(path_ext)]
 #![feature(fs)]
-#![feature(convert)]
 #![feature(path_relative_from)]
 
 #![allow(trivial_casts)]

src/librustdoc/lib.rs

@@ -36,7 +36,6 @@
 #![feature(file_path)]
 #![feature(path_ext)]
 #![feature(path_relative_from)]
-#![feature(convert)]
 #![feature(slice_patterns)]
 
 extern crate arena;

src/libserialize/lib.rs

@@ -36,7 +36,6 @@ Core encoding and decoding interfaces.
 #![feature(std_misc)]
 #![feature(unicode)]
 #![feature(str_char)]
-#![feature(convert)]
 #![cfg_attr(test, feature(test, old_io))]
 
 // test harness access

src/libstd/dynamic_lib.rs

@@ -190,7 +190,6 @@ mod dl {
     use ffi::{CStr, OsStr};
     use str;
     use libc;
-    use os::unix::prelude::*;
     use ptr;
 
     pub fn open(filename: Option<&OsStr>) -> Result<*mut u8, String> {

src/libstd/env.rs

@@ -327,7 +327,6 @@ pub struct JoinPathsError {
 /// # Examples
 ///
 /// ```
-/// # #![feature(convert)]
 /// use std::env;
 /// use std::path::PathBuf;
 ///

src/libstd/ffi/os_str.rs

@@ -35,6 +35,7 @@
 use core::prelude::*;
 
 use borrow::{Borrow, Cow, ToOwned};
+use ffi::CString;
 use fmt::{self, Debug};
 use mem;
 use string::String;
@@ -42,6 +43,7 @@ use ops;
 use cmp;
 use hash::{Hash, Hasher};
 use old_path::{Path, GenericPath};
+use vec::Vec;
 
 use sys::os_str::{Buf, Slice};
 use sys_common::{AsInner, IntoInner, FromInner};
@@ -83,6 +85,37 @@ impl OsString {
         OsString { inner: Buf::from_string(String::new()) }
     }
 
+    /// Construct an `OsString` from a byte sequence.
+    ///
+    /// # Platform behavior
+    ///
+    /// On Unix systems, any byte sequence can be successfully
+    /// converted into an `OsString`.
+    ///
+    /// On Windows system, only UTF-8 byte sequences will successfully
+    /// convert; non UTF-8 data will produce `None`.
+    #[unstable(feature = "convert", reason = "recently added")]
+    pub fn from_bytes<B>(bytes: B) -> Option<OsString> where B: Into<Vec<u8>> {
+        #[cfg(unix)]
+        fn from_bytes_inner(vec: Vec<u8>) -> Option<OsString> {
+            use os::unix::ffi::OsStringExt;
+            Some(OsString::from_vec(vec))
+        }
+
+        #[cfg(windows)]
+        fn from_bytes_inner(vec: Vec<u8>) -> Option<OsString> {
+            String::from_utf8(vec).ok().map(OsString::from)
+        }
+
+        from_bytes_inner(bytes.into())
+    }
+
+    /// Convert to an `OsStr` slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn as_os_str(&self) -> &OsStr {
+        self
+    }
+
     /// Convert the `OsString` into a `String` if it contains valid Unicode data.
     ///
     /// On failure, ownership of the original `OsString` is returned.
@@ -211,8 +244,16 @@ impl Hash for OsString {
 }
 
 impl OsStr {
+    /// Coerce into an `OsStr` slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &OsStr {
+        s.as_ref()
+    }
+
     /// Coerce directly from a `&str` slice to a `&OsStr` slice.
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[deprecated(since = "1.0.0",
+                 reason = "use `OsStr::new` instead")]
     pub fn from_str(s: &str) -> &OsStr {
         unsafe { mem::transmute(Slice::from_str(s)) }
     }
@@ -239,6 +280,36 @@ impl OsStr {
         OsString { inner: self.inner.to_owned() }
     }
 
+    /// Yield this `OsStr` as a byte slice.
+    ///
+    /// # Platform behavior
+    ///
+    /// On Unix systems, this is a no-op.
+    ///
+    /// On Windows systems, this returns `None` unless the `OsStr` is
+    /// valid unicode, in which case it produces UTF-8-encoded
+    /// data. This may entail checking validity.
+    #[unstable(feature = "convert", reason = "recently added")]
+    pub fn to_bytes(&self) -> Option<&[u8]> {
+        if cfg!(windows) {
+            self.to_str().map(|s| s.as_bytes())
+        } else {
+            Some(self.bytes())
+        }
+    }
+
+    /// Create a `CString` containing this `OsStr` data.
+    ///
+    /// Fails if the `OsStr` contains interior nulls.
+    ///
+    /// This is a convenience for creating a `CString` from
+    /// `self.to_bytes()`, and inherits the platform behavior of the
+    /// `to_bytes` method.
+    #[unstable(feature = "convert", reason = "recently added")]
+    pub fn to_cstring(&self) -> Option<CString> {
+        self.to_bytes().and_then(|b| CString::new(b).ok())
+    }
+
     /// Get the underlying byte representation.
     ///
     /// Note: it is *crucial* that this API is private, to avoid
@@ -258,14 +329,14 @@ impl PartialEq for OsStr {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl PartialEq<str> for OsStr {
     fn eq(&self, other: &str) -> bool {
-        *self == *OsStr::from_str(other)
+        *self == *OsStr::new(other)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl PartialEq<OsStr> for str {
     fn eq(&self, other: &OsStr) -> bool {
-        *other == *OsStr::from_str(self)
+        *other == *OsStr::new(self)
     }
 }
 
@@ -292,7 +363,7 @@ impl PartialOrd for OsStr {
 impl PartialOrd<str> for OsStr {
     #[inline]
     fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
-        self.partial_cmp(OsStr::from_str(other))
+        self.partial_cmp(OsStr::new(other))
     }
 }
 
@@ -359,7 +430,7 @@ impl AsOsStr for OsString {
 #[deprecated(since = "1.0.0", reason = "trait is deprecated")]
 impl AsOsStr for str {
     fn as_os_str(&self) -> &OsStr {
-        OsStr::from_str(self)
+        unsafe { mem::transmute(Slice::from_str(self)) }
     }
 }
 
@@ -367,7 +438,7 @@ impl AsOsStr for str {
 #[deprecated(since = "1.0.0", reason = "trait is deprecated")]
 impl AsOsStr for String {
     fn as_os_str(&self) -> &OsStr {
-        OsStr::from_str(&self[..])
+        unsafe { mem::transmute(Slice::from_str(self)) }
     }
 }
 
@@ -388,14 +459,14 @@ impl AsRef<OsStr> for OsString {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<OsStr> for str {
     fn as_ref(&self) -> &OsStr {
-        OsStr::from_str(self)
+        unsafe { mem::transmute(Slice::from_str(self)) }
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<OsStr> for String {
     fn as_ref(&self) -> &OsStr {
-        OsStr::from_str(&self[..])
+        unsafe { mem::transmute(Slice::from_str(self)) }
     }
 }
 

src/libstd/lib.rs

@@ -122,12 +122,11 @@
 #![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(macro_reexport)]
 #![feature(unique)]
-#![feature(convert)]
 #![feature(allow_internal_unstable)]
 #![feature(str_char)]
 #![feature(into_cow)]
-#![feature(slice_patterns)]
 #![feature(std_misc)]
+#![feature(slice_patterns)]
 #![feature(debug_builders)]
 #![cfg_attr(test, feature(test, rustc_private, std_misc))]
 

src/libstd/path.rs

@@ -35,7 +35,6 @@
 //! To build or modify paths, use `PathBuf`:
 //!
 //! ```rust
-//! # #![feature(convert)]
 //! use std::path::PathBuf;
 //!
 //! let mut path = PathBuf::from("c:\\");
@@ -521,9 +520,9 @@ impl<'a> Component<'a> {
     pub fn as_os_str(self) -> &'a OsStr {
         match self {
             Component::Prefix(p) => p.as_os_str(),
-            Component::RootDir => OsStr::from_str(MAIN_SEP_STR),
-            Component::CurDir => OsStr::from_str("."),
-            Component::ParentDir => OsStr::from_str(".."),
+            Component::RootDir => OsStr::new(MAIN_SEP_STR),
+            Component::CurDir => OsStr::new("."),
+            Component::ParentDir => OsStr::new(".."),
             Component::Normal(path) => path,
         }
     }
@@ -893,7 +892,6 @@ impl<'a> cmp::Ord for Components<'a> {
 /// # Examples
 ///
 /// ```
-/// # #![feature(convert)]
 /// use std::path::PathBuf;
 ///
 /// let mut path = PathBuf::from("c:\\");
@@ -918,6 +916,12 @@ impl PathBuf {
         PathBuf { inner: OsString::new() }
     }
 
+    /// Coerce to a `Path` slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn as_path(&self) -> &Path {
+        self
+    }
+
     /// Extend `self` with `path`.
     ///
     /// If `path` is absolute, it replaces the current path.
@@ -985,7 +989,6 @@ impl PathBuf {
     /// # Examples
     ///
     /// ```
-    /// # #![feature(convert)]
     /// use std::path::PathBuf;
     ///
     /// let mut buf = PathBuf::from("/");

src/libstd/sys/unix/ext.rs

@@ -138,7 +138,7 @@ pub mod io {
 /// Unix-specific extension to the primitives in the `std::ffi` module
 #[stable(feature = "rust1", since = "1.0.0")]
 pub mod ffi {
-    use ffi::{CString, NulError, OsStr, OsString};
+    use ffi::{OsStr, OsString};
     use mem;
     use prelude::v1::*;
     use sys::os_str::Buf;
@@ -175,10 +175,6 @@ pub mod ffi {
         /// Get the underlying byte view of the `OsStr` slice.
         #[stable(feature = "rust1", since = "1.0.0")]
         fn as_bytes(&self) -> &[u8];
-
-        /// Convert the `OsStr` slice into a `CString`.
-        #[stable(feature = "rust1", since = "1.0.0")]
-        fn to_cstring(&self) -> Result<CString, NulError>;
     }
 
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -189,9 +185,6 @@ pub mod ffi {
         fn as_bytes(&self) -> &[u8] {
             &self.as_inner().inner
         }
-        fn to_cstring(&self) -> Result<CString, NulError> {
-            CString::new(self.as_bytes())
-        }
     }
 }
 

src/libstd/sys/unix/fs2.rs

@@ -276,8 +276,8 @@ impl File {
 }
 
 fn cstr(path: &Path) -> io::Result<CString> {
-    let cstring = try!(path.as_os_str().to_cstring());
-    Ok(cstring)
+    path.as_os_str().to_cstring().ok_or(
+        io::Error::new(io::ErrorKind::InvalidInput, "path contained a null", None))
 }
 
 pub fn mkdir(p: &Path) -> io::Result<()> {

src/libstd/sys/unix/process2.rs

@@ -54,7 +54,7 @@ impl Command {
         self.args.push(arg.to_cstring().unwrap())
     }
     pub fn args<'a, I: Iterator<Item = &'a OsStr>>(&mut self, args: I) {
-        self.args.extend(args.map(|s| OsStrExt::to_cstring(s).unwrap()))
+        self.args.extend(args.map(|s| s.to_cstring().unwrap()))
     }
     fn init_env_map(&mut self) {
         if self.env.is_none() {

src/libsyntax/lib.rs

@@ -37,7 +37,6 @@
 #![feature(unicode)]
 #![feature(path_ext)]
 #![feature(str_char)]
-#![feature(convert)]
 #![feature(into_cow)]
 #![feature(slice_patterns)]
 

src/libterm/lib.rs

@@ -62,7 +62,6 @@
 #![feature(std_misc)]
 #![feature(str_char)]
 #![feature(path_ext)]
-#![feature(convert)]
 #![cfg_attr(windows, feature(libc))]
 
 #[macro_use] extern crate log;

src/libtest/lib.rs

@@ -44,7 +44,6 @@
 #![feature(libc)]
 #![feature(set_stdio)]
 #![feature(os)]
-#![feature(convert)]
 #![cfg_attr(test, feature(old_io))]
 
 extern crate getopts;

src/rustbook/main.rs

@@ -15,7 +15,6 @@
 #![feature(rustdoc)]
 #![feature(rustc_private)]
 #![feature(path_relative_from)]
-#![feature(convert)]
 
 extern crate rustdoc;
 extern crate rustc_back;

src/test/run-pass/env-home-dir.rs

@@ -11,7 +11,6 @@
 // pretty-expanded FIXME #23616
 
 #![feature(path)]
-#![feature(convert)]
 
 use std::env::*;
 use std::path::PathBuf;

src/test/run-pass/issue-20797.rs

@@ -12,8 +12,6 @@
 
 // pretty-expanded FIXME #23616
 
-#![feature(convert)]
-
 use std::default::Default;
 use std::io;
 use std::fs;