Rollup merge of #22727 - alexcrichton:prep-env, r=aturon

 This commit moves `std::env` away from the `std::old_io` error type as well as
the `std::old_path` module. Methods returning an error now return `io::Error`
and methods consuming or returning paths use `std::path` instead of
`std::old_path`. This commit does not yet mark these APIs as `#[stable]`.

This commit also migrates `std::old_io::TempDir` to `std::fs::TempDir` with
essentially the exact same API. This type was added to interoperate with the new
path API and has its own `tempdir` feature.

Finally, this commit reverts the deprecation of `std::os` APIs returning the old
path API types. This deprecation can come back once the entire `std::old_path`
module is deprecated.

[breaking-change]

5 files changed, 11 insertions, 9 deletions

diff --git a/src/librustc_back/archive.rs b/src/librustc_back/archive.rs
index 6bf745315ea..3fcae6a8034 100644
--- a/src/librustc_back/archive.rs
+++ b/src/librustc_back/archive.rs
@@ -14,7 +14,7 @@ use std::old_io::fs::PathExtensions;
 use std::old_io::process::{Command, ProcessOutput};
 use std::old_io::{fs, TempDir};
 use std::old_io;
-use std::env;
+use std::os;
 use std::str;
 use syntax::diagnostic::Handler as ErrorHandler;
 
@@ -224,7 +224,7 @@ impl<'a> ArchiveBuilder<'a> {
     pub fn build(self) -> Archive<'a> {
         // Get an absolute path to the destination, so `ar` will work even
         // though we run it from `self.work_dir`.
-        let abs_dst = env::current_dir().unwrap().join(&self.archive.dst);
+        let abs_dst = os::getcwd().unwrap().join(&self.archive.dst);
         assert!(!abs_dst.is_relative());
         let mut args = vec![&abs_dst];
         let mut total_len = abs_dst.as_vec().len();
@@ -283,7 +283,7 @@ impl<'a> ArchiveBuilder<'a> {
         // First, extract the contents of the archive to a temporary directory.
         // We don't unpack directly into `self.work_dir` due to the possibility
         // of filename collisions.
-        let archive = env::current_dir().unwrap().join(archive);
+        let archive = os::getcwd().unwrap().join(archive);
         run_ar(self.archive.handler, &self.archive.maybe_ar_prog,
                "x", Some(loc.path()), &[&archive]);
 
diff --git a/src/librustc_back/fs.rs b/src/librustc_back/fs.rs
index acf49d1ca46..99a1df95a80 100644
--- a/src/librustc_back/fs.rs
+++ b/src/librustc_back/fs.rs
@@ -10,13 +10,13 @@
 
 use std::old_io;
 use std::old_io::fs;
-use std::env;
+use std::os;
 
 /// Returns an absolute path in the filesystem that `path` points to. The
 /// returned path does not contain any symlinks in its hierarchy.
 pub fn realpath(original: &Path) -> old_io::IoResult<Path> {
     static MAX_LINKS_FOLLOWED: uint = 256;
-    let original = try!(env::current_dir()).join(original);
+    let original = try!(os::getcwd()).join(original);
 
     // Right now lstat on windows doesn't work quite well
     if cfg!(windows) {
diff --git a/src/librustc_back/lib.rs b/src/librustc_back/lib.rs
index d589b063204..711f937d2f3 100644
--- a/src/librustc_back/lib.rs
+++ b/src/librustc_back/lib.rs
@@ -41,6 +41,7 @@
 #![feature(rustc_private)]
 #![feature(staged_api)]
 #![feature(env)]
+#![feature(path)]
 
 extern crate syntax;
 extern crate serialize;
diff --git a/src/librustc_back/rpath.rs b/src/librustc_back/rpath.rs
index 3f2dcee5110..943ff52925a 100644
--- a/src/librustc_back/rpath.rs
+++ b/src/librustc_back/rpath.rs
@@ -8,10 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 use std::collections::HashSet;
 use std::env;
 use std::old_io::IoError;
+use std::os;
 use syntax::ast;
 
 pub struct RPathConfig<F, G> where
@@ -109,7 +109,7 @@ fn get_rpath_relative_to_output<F, G>(config: &mut RPathConfig<F, G>, lib: &Path
         "$ORIGIN"
     };
 
-    let cwd = env::current_dir().unwrap();
+    let cwd = os::getcwd().unwrap();
     let mut lib = (config.realpath)(&cwd.join(lib)).unwrap();
     lib.pop();
     let mut output = (config.realpath)(&cwd.join(&config.out_filename)).unwrap();
@@ -129,7 +129,7 @@ fn get_install_prefix_rpath<F, G>(config: RPathConfig<F, G>) -> String where
     let path = (config.get_install_prefix_lib_path)();
     let path = env::current_dir().unwrap().join(&path);
     // FIXME (#9639): This needs to handle non-utf8 paths
-    path.as_str().expect("non-utf8 component in rpath").to_string()
+    path.to_str().expect("non-utf8 component in rpath").to_string()
 }
 
 fn minimize_rpaths(rpaths: &[String]) -> Vec<String> {
diff --git a/src/librustc_back/target/mod.rs b/src/librustc_back/target/mod.rs
index b04c07977c3..d09a7c355d3 100644
--- a/src/librustc_back/target/mod.rs
+++ b/src/librustc_back/target/mod.rs
@@ -310,6 +310,7 @@ impl Target {
     /// JSON decoding.
     pub fn search(target: &str) -> Result<Target, String> {
         use std::env;
+        use std::os;
         use std::ffi::OsString;
         use std::old_io::File;
         use std::old_path::Path;
@@ -396,7 +397,7 @@ impl Target {
 
         // FIXME 16351: add a sane default search path?
 
-        for dir in env::split_paths(&target_path) {
+        for dir in os::split_paths(target_path.to_str().unwrap()).iter() {
             let p =  dir.join(path.clone());
             if p.is_file() {
                 return load_file(&p);