std: Stabilize the ffi module

The two main sub-modules, `c_str` and `os_str`, have now had some time to bake
in the standard library. This commits performs a sweep over the modules adding
various stability tags.

The following APIs are now marked `#[stable]`

* `OsString`
* `OsStr`
* `OsString::from_string`
* `OsString::from_str`
* `OsString::new`
* `OsString::into_string`
* `OsString::push` (renamed from `push_os_str`, added an `AsOsStr` bound)
* various trait implementations for `OsString`
* `OsStr::from_str`
* `OsStr::to_str`
* `OsStr::to_string_lossy`
* `OsStr::to_os_string`
* various trait implementations for `OsStr`
* `CString`
* `CStr`
* `NulError`
* `CString::new` - this API's implementation may change as a result of
  rust-lang/rfcs#912 but the usage of `CString::new(thing)` looks like it is
  unlikely to change. Additionally, the `IntoBytes` bound is also likely to
  change but the set of implementors for the trait will not change (despite the
  trait perhaps being renamed).
* `CString::from_vec_unchecked`
* `CString::as_bytes`
* `CString::as_bytes_with_nul`
* `NulError::nul_position`
* `NulError::into_vec`
* `CStr::from_ptr`
* `CStr::as_ptr`
* `CStr::to_bytes`
* `CStr::to_bytes_with_nul`
* various trait implementations for `CStr`

The following APIs remain `#[unstable]`

* `OsStr*Ext` traits remain unstable as the organization of `os::platform` is
  uncertain still and the traits may change location.
* `AsOsStr` remains unstable as generic conversion traits are likely to be
  rethought soon.

The following APIs were deprecated

* `OsString::push_os_str` is now called `push` and takes `T: AsOsStr` instead (a
  superset of the previous functionality).

Author: alexcrichton

Diff for: src/compiletest/compiletest.rs

@@ -22,7 +22,6 @@
 #![feature(unicode)]
 #![feature(core)]
 #![feature(path)]
-#![feature(os)]
 #![feature(io)]
 #![feature(fs)]
 #![feature(net)]

Diff for: src/compiletest/runtest.rs

@@ -20,7 +20,6 @@ use procsrv;
 use util::logv;
 
 use std::env;
-use std::ffi::OsStr;
 use std::fmt;
 use std::fs::{self, File};
 use std::io::BufReader;
@@ -1323,7 +1322,7 @@ fn make_exe_name(config: &Config, testfile: &Path) -> PathBuf {
     let mut f = output_base_name(config, testfile);
     if !env::consts::EXE_SUFFIX.is_empty() {
         let mut fname = f.file_name().unwrap().to_os_string();
-        fname.push_os_str(OsStr::from_str(env::consts::EXE_SUFFIX));
+        fname.push(env::consts::EXE_SUFFIX);
         f.set_file_name(&fname);
     }
     f
@@ -1433,7 +1432,7 @@ fn make_out_name(config: &Config, testfile: &Path, extension: &str) -> PathBuf {
 fn aux_output_dir_name(config: &Config, testfile: &Path) -> PathBuf {
     let f = output_base_name(config, testfile);
     let mut fname = f.file_name().unwrap().to_os_string();
-    fname.push_os_str(OsStr::from_str("libaux"));
+    fname.push("libaux");
     f.with_file_name(&fname)
 }
 
@@ -1647,8 +1646,8 @@ fn append_suffix_to_stem(p: &Path, suffix: &str) -> PathBuf {
         p.to_path_buf()
     } else {
         let mut stem = p.file_stem().unwrap().to_os_string();
-        stem.push_os_str(OsStr::from_str("-"));
-        stem.push_os_str(OsStr::from_str(suffix));
+        stem.push("-");
+        stem.push(suffix);
         p.with_file_name(&stem)
     }
 }

Diff for: src/librustc/lib.rs

@@ -38,7 +38,6 @@
 #![feature(unsafe_destructor)]
 #![feature(staged_api)]
 #![feature(std_misc)]
-#![feature(os)]
 #![feature(path)]
 #![feature(fs)]
 #![feature(io)]

Diff for: src/librustc_driver/lib.rs

@@ -29,7 +29,6 @@
 #![feature(int_uint)]
 #![feature(old_io)]
 #![feature(libc)]
-#![feature(os)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]

Diff for: src/librustc_trans/back/link.rs

@@ -27,7 +27,7 @@ use util::common::time;
 use util::ppaux;
 use util::sha2::{Digest, Sha256};
 
-use std::ffi::{AsOsStr, OsString};
+use std::ffi::OsString;
 use std::fs::{self, TempDir, PathExt};
 use std::io::{self, Read, Write};
 use std::mem;
@@ -882,7 +882,7 @@ fn link_args(cmd: &mut Command,
             let morestack = lib_path.join("libmorestack.a");
 
             let mut v = OsString::from_str("-Wl,-force_load,");
-            v.push_os_str(morestack.as_os_str());
+            v.push(&morestack);
             cmd.arg(&v);
         } else {
             cmd.args(&["-Wl,--whole-archive", "-lmorestack", "-Wl,--no-whole-archive"]);
@@ -1007,7 +1007,7 @@ fn link_args(cmd: &mut Command,
 
             if sess.opts.cg.rpath {
                 let mut v = OsString::from_str("-Wl,-install_name,@rpath/");
-                v.push_os_str(out_filename.file_name().unwrap());
+                v.push(out_filename.file_name().unwrap());
                 cmd.arg(&v);
             }
         } else {
@@ -1107,7 +1107,7 @@ fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
                                             &search_path[..],
                                             &sess.diagnostic().handler);
             let mut v = OsString::from_str("-Wl,-force_load,");
-            v.push_os_str(lib.as_os_str());
+            v.push(&lib);
             cmd.arg(&v);
         }
     }

Diff for: src/librustc_trans/lib.rs

@@ -35,12 +35,10 @@
 #![feature(rustc_private)]
 #![feature(unsafe_destructor)]
 #![feature(staged_api)]
-#![feature(std_misc)]
 #![feature(unicode)]
 #![feature(io)]
 #![feature(fs)]
 #![feature(path)]
-#![feature(os)]
 #![feature(tempdir)]
 
 extern crate arena;

Diff for: src/librustdoc/html/render.rs

@@ -38,7 +38,6 @@ use std::cell::RefCell;
 use std::cmp::Ordering;
 use std::collections::{HashMap, HashSet};
 use std::default::Default;
-use std::ffi::OsStr;
 use std::fmt;
 use std::fs::{self, File};
 use std::io::prelude::*;
@@ -770,7 +769,7 @@ impl<'a> SourceCollector<'a> {
 
         let mut fname = p.file_name().expect("source has no filename")
                          .to_os_string();
-        fname.push_os_str(OsStr::from_str(".html"));
+        fname.push(".html");
         cur.push(&fname);
         let mut w = BufWriter::new(try!(File::create(&cur)));
 

Diff for: src/libstd/ffi/c_str.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![unstable(feature = "std_misc")]
+
 use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
 use error::{Error, FromError};
 use fmt;
@@ -59,6 +61,7 @@ use vec::Vec;
 /// # }
 /// ```
 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[stable(feature = "rust1", since = "1.0.0")]
 pub struct CString {
     inner: Vec<u8>,
 }
@@ -110,13 +113,19 @@ pub struct CString {
 /// }
 /// ```
 #[derive(Hash)]
+#[stable(feature = "rust1", since = "1.0.0")]
 pub struct CStr {
+    // FIXME: this should not be represented with a DST slice but rather with
+    //        just a raw `libc::c_char` along with some form of marker to make
+    //        this an unsized type. Essentially `sizeof(&CStr)` should be the
+    //        same as `sizeof(&c_char)` but `CStr` should be an unsized type.
     inner: [libc::c_char]
 }
 
 /// An error returned from `CString::new` to indicate that a nul byte was found
 /// in the vector provided.
 #[derive(Clone, PartialEq, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
 pub struct NulError(usize, Vec<u8>);
 
 /// A conversion trait used by the constructor of `CString` for types that can
@@ -153,6 +162,7 @@ impl CString {
     /// This function will return an error if the bytes yielded contain an
     /// internal 0 byte. The error returned will contain the bytes as well as
     /// the position of the nul byte.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new<T: IntoBytes>(t: T) -> Result<CString, NulError> {
         let bytes = t.into_bytes();
         match bytes.iter().position(|x| *x == 0) {
@@ -216,6 +226,7 @@ impl CString {
     ///
     /// This method is equivalent to `from_vec` except that no runtime assertion
     /// is made that `v` contains no 0 bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub unsafe fn from_vec_unchecked(mut v: Vec<u8>) -> CString {
         v.push(0);
         CString { inner: v }
@@ -225,17 +236,20 @@ impl CString {
     ///
     /// The returned slice does **not** contain the trailing nul separator and
     /// it is guaranteed to not have any interior nul bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn as_bytes(&self) -> &[u8] {
         &self.inner[..self.inner.len() - 1]
     }
 
     /// Equivalent to the `as_bytes` function except that the returned slice
     /// includes the trailing nul byte.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn as_bytes_with_nul(&self) -> &[u8] {
         &self.inner
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl Deref for CString {
     type Target = CStr;
 
@@ -254,30 +268,36 @@ impl fmt::Debug for CString {
 impl NulError {
     /// Returns the position of the nul byte in the slice that was provided to
     /// `CString::from_vec`.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn nul_position(&self) -> usize { self.0 }
 
     /// Consumes this error, returning the underlying vector of bytes which
     /// generated the error in the first place.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn into_vec(self) -> Vec<u8> { self.1 }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl Error for NulError {
     fn description(&self) -> &str { "nul byte found in data" }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for NulError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "nul byte found in provided data at position: {}", self.0)
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl FromError<NulError> for io::Error {
     fn from_error(_: NulError) -> io::Error {
         io::Error::new(io::ErrorKind::InvalidInput,
                        "data provided contains a nul byte", None)
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl FromError<NulError> for old_io::IoError {
     fn from_error(_: NulError) -> old_io::IoError {
         old_io::IoError {
@@ -325,6 +345,7 @@ impl CStr {
     /// }
     /// # }
     /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub unsafe fn from_ptr<'a>(ptr: *const libc::c_char) -> &'a CStr {
         let len = libc::strlen(ptr);
         mem::transmute(slice::from_raw_parts(ptr, len as usize + 1))
@@ -335,6 +356,7 @@ impl CStr {
     /// The returned pointer will be valid for as long as `self` is and points
     /// to a contiguous region of memory terminated with a 0 byte to represent
     /// the end of the string.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn as_ptr(&self) -> *const libc::c_char {
         self.inner.as_ptr()
     }
@@ -351,6 +373,7 @@ impl CStr {
     /// > **Note**: This method is currently implemented as a 0-cost cast, but
     /// > it is planned to alter its definition in the future to perform the
     /// > length calculation whenever this method is called.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn to_bytes(&self) -> &[u8] {
         let bytes = self.to_bytes_with_nul();
         &bytes[..bytes.len() - 1]
@@ -364,22 +387,27 @@ impl CStr {
     /// > **Note**: This method is currently implemented as a 0-cost cast, but
     /// > it is planned to alter its definition in the future to perform the
     /// > length calculation whenever this method is called.
+    #[stable(feature = "rust1", since = "1.0.0")]
     pub fn to_bytes_with_nul(&self) -> &[u8] {
         unsafe { mem::transmute::<&[libc::c_char], &[u8]>(&self.inner) }
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl PartialEq for CStr {
     fn eq(&self, other: &CStr) -> bool {
         self.to_bytes().eq(other.to_bytes())
     }
 }
+#[stable(feature = "rust1", since = "1.0.0")]
 impl Eq for CStr {}
+#[stable(feature = "rust1", since = "1.0.0")]
 impl PartialOrd for CStr {
     fn partial_cmp(&self, other: &CStr) -> Option<Ordering> {
         self.to_bytes().partial_cmp(&other.to_bytes())
     }
 }
+#[stable(feature = "rust1", since = "1.0.0")]
 impl Ord for CStr {
     fn cmp(&self, other: &CStr) -> Ordering {
         self.to_bytes().cmp(&other.to_bytes())

Diff for: src/libstd/ffi/mod.rs

@@ -10,24 +10,27 @@
 
 //! Utilities related to FFI bindings.
 
-#![unstable(feature = "std_misc",
-            reason = "module just underwent fairly large reorganization and the dust \
-                      still needs to settle")]
+#![stable(feature = "rust1", since = "1.0.0")]
 
-pub use self::c_str::{CString, CStr, NulError, IntoBytes};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::c_str::{CString, CStr};
+pub use self::c_str::{NulError, IntoBytes};
 #[allow(deprecated)]
 pub use self::c_str::c_str_to_bytes;
 #[allow(deprecated)]
 pub use self::c_str::c_str_to_bytes_with_nul;
 
+#[stable(feature = "rust1", since = "1.0.0")]
 pub use self::os_str::OsString;
+#[stable(feature = "rust1", since = "1.0.0")]
 pub use self::os_str::OsStr;
 
 mod c_str;
 mod os_str;
 
 // FIXME (#21670): these should be defined in the os_str module
 /// Freely convertible to an `&OsStr` slice.
+#[unstable(feature = "std_misc")]
 pub trait AsOsStr {
     /// Convert to an `&OsStr` slice.
     fn as_os_str(&self) -> &OsStr;