std: Expand the area of std::fs

This commit is an implementation of [RFC 1044][rfc] which adds additional
surface area to the `std::fs` module. All new APIs are `#[unstable]` behind
assorted feature names for each one.

[rfc]: rust-lang/rfcs#1044

The new APIs added are:

* `fs::canonicalize` - bindings to `realpath` on unix and
  `GetFinalPathNameByHandle` on windows.
* `fs::symlink_metadata` - similar to `lstat` on unix
* `fs::FileType` and accessor methods as `is_{file,dir,symlink}`
* `fs::Metadata::file_type` - accessor for the raw file type
* `fs::DirEntry::metadata` - acquisition of metadata which is free on Windows
  but requires a syscall on unix.
* `fs::DirEntry::file_type` - access the file type which may not require a
  syscall on most platforms.
* `fs::DirEntry::file_name` - access just the file name without leading
  components.
* `fs::PathExt::symlink_metadata` - convenience method for the top-level
  function.
* `fs::PathExt::canonicalize` - convenience method for the top-level
  function.
* `fs::PathExt::read_link` - convenience method for the top-level
  function.
* `fs::PathExt::read_dir` - convenience method for the top-level
  function.
* `std::os::raw` - type definitions for raw OS/C types available on all
  platforms.
* `std::os::$platform` - new modules have been added for all currently supported
  platforms (e.g. those more specific than just `unix`).
* `std::os::$platform::raw` - platform-specific type definitions. These modules
  are populated with the bare essentials necessary for lowing I/O types into
  their raw representations, and currently largely consist of the `stat`
  definition for unix platforms.

This commit also deprecates `Metadata::{modified, accessed}` in favor of
inspecting the raw representations via the lowering methods of `Metadata`.

src/librustc/lib.rs

@@ -40,6 +40,7 @@
 #![feature(path_ext)]
 #![feature(str_char)]
 #![feature(into_cow)]
+#![feature(fs_canonicalize)]
 #![feature(slice_patterns)]
 #![cfg_attr(test, feature(test))]
 
@@ -139,7 +140,6 @@ pub mod plugin;
 pub mod lint;
 
 pub mod util {
-    pub use rustc_back::fs;
     pub use rustc_back::sha2;
 
     pub mod common;

src/librustc/metadata/creader.rs

@@ -21,8 +21,10 @@ use metadata::decoder;
 use metadata::loader;
 use metadata::loader::CratePaths;
 
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::rc::Rc;
+use std::fs;
+
 use syntax::ast;
 use syntax::abi;
 use syntax::attr;
@@ -32,7 +34,6 @@ use syntax::parse;
 use syntax::parse::token::InternedString;
 use syntax::parse::token;
 use syntax::visit;
-use util::fs;
 use log;
 
 pub struct CrateReader<'a> {
@@ -322,7 +323,7 @@ impl<'a> CrateReader<'a> {
             let source = self.sess.cstore.get_used_crate_source(cnum).unwrap();
             if let Some(locs) = self.sess.opts.externs.get(name) {
                 let found = locs.iter().any(|l| {
-                    let l = fs::realpath(&Path::new(&l[..])).ok();
+                    let l = fs::canonicalize(l).ok();
                     source.dylib.as_ref().map(|p| &p.0) == l.as_ref() ||
                     source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
                 });

src/librustc/metadata/filesearch.rs

@@ -18,7 +18,6 @@ use std::fs;
 use std::io::prelude::*;
 use std::path::{Path, PathBuf};
 
-use util::fs as myfs;
 use session::search_paths::{SearchPaths, PathKind};
 
 #[derive(Copy, Clone)]
@@ -191,7 +190,7 @@ pub fn get_or_default_sysroot() -> PathBuf {
     // Follow symlinks.  If the resolved path is relative, make it absolute.
     fn canonicalize(path: Option<PathBuf>) -> Option<PathBuf> {
         path.and_then(|path| {
-            match myfs::realpath(&path) {
+            match fs::canonicalize(&path) {
                 Ok(canon) => Some(canon),
                 Err(e) => panic!("failed to get realpath: {}", e),
             }

src/librustc/metadata/loader.rs

@@ -225,12 +225,12 @@ use metadata::encoder;
 use metadata::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
 use syntax::codemap::Span;
 use syntax::diagnostic::SpanHandler;
-use util::fs;
 use util::common;
 use rustc_back::target::Target;
 
 use std::cmp;
 use std::collections::HashMap;
+use std::fs;
 use std::io::prelude::*;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -430,9 +430,9 @@ impl<'a> Context<'a> {
                                  .or_insert_with(|| (HashMap::new(), HashMap::new()));
             let (ref mut rlibs, ref mut dylibs) = *slot;
             if rlib {
-                rlibs.insert(fs::realpath(path).unwrap(), kind);
+                rlibs.insert(fs::canonicalize(path).unwrap(), kind);
             } else {
-                dylibs.insert(fs::realpath(path).unwrap(), kind);
+                dylibs.insert(fs::canonicalize(path).unwrap(), kind);
             }
 
             FileMatches
@@ -660,10 +660,10 @@ impl<'a> Context<'a> {
             // there's at most one rlib and at most one dylib.
             for loc in locs {
                 if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
-                    rlibs.insert(fs::realpath(&loc).unwrap(),
+                    rlibs.insert(fs::canonicalize(&loc).unwrap(),
                                  PathKind::ExternFlag);
                 } else {
-                    dylibs.insert(fs::realpath(&loc).unwrap(),
+                    dylibs.insert(fs::canonicalize(&loc).unwrap(),
                                   PathKind::ExternFlag);
                 }
             }

src/librustc_back/lib.rs

@@ -41,6 +41,7 @@
 #![feature(path_ext)]
 #![feature(step_by)]
 #![feature(libc)]
+#![feature(fs_canonicalize)]
 #![cfg_attr(test, feature(test, rand))]
 
 extern crate syntax;
@@ -53,7 +54,6 @@ pub mod abi;
 pub mod archive;
 pub mod tempdir;
 pub mod arm;
-pub mod fs;
 pub mod mips;
 pub mod mipsel;
 pub mod rpath;

src/librustc_back/rpath.rs

@@ -10,8 +10,8 @@
 
 use std::collections::HashSet;
 use std::env;
-use std::io;
 use std::path::{Path, PathBuf};
+use std::fs;
 use syntax::ast;
 
 pub struct RPathConfig<'a> {
@@ -20,7 +20,6 @@ pub struct RPathConfig<'a> {
     pub is_like_osx: bool,
     pub has_rpath: bool,
     pub get_install_prefix_lib_path: &'a mut FnMut() -> PathBuf,
-    pub realpath: &'a mut FnMut(&Path) -> io::Result<PathBuf>,
 }
 
 pub fn get_rpath_flags(config: &mut RPathConfig) -> Vec<String> {
@@ -95,11 +94,11 @@ fn get_rpath_relative_to_output(config: &mut RPathConfig, lib: &Path) -> String
     };
 
     let cwd = env::current_dir().unwrap();
-    let mut lib = (config.realpath)(&cwd.join(lib)).unwrap();
+    let mut lib = fs::canonicalize(&cwd.join(lib)).unwrap_or(cwd.join(lib));
     lib.pop();
     let mut output = cwd.join(&config.out_filename);
     output.pop();
-    let output = (config.realpath)(&output).unwrap();
+    let output = fs::canonicalize(&output).unwrap_or(output);
     let relative = path_relative_from(&lib, &output)
         .expect(&format!("couldn't create relative path from {:?} to {:?}", output, lib));
     // FIXME (#9639): This needs to handle non-utf8 paths
@@ -231,7 +230,6 @@ mod tests {
                 is_like_osx: true,
                 out_filename: PathBuf::from("bin/rustc"),
                 get_install_prefix_lib_path: &mut || panic!(),
-                realpath: &mut |p| Ok(p.to_path_buf()),
             };
             let res = get_rpath_relative_to_output(config,
                                                    Path::new("lib/libstd.so"));
@@ -243,7 +241,6 @@ mod tests {
                 get_install_prefix_lib_path: &mut || panic!(),
                 has_rpath: true,
                 is_like_osx: false,
-                realpath: &mut |p| Ok(p.to_path_buf()),
             };
             let res = get_rpath_relative_to_output(config,
                                                    Path::new("lib/libstd.so"));

src/librustc_trans/back/link.rs

@@ -32,7 +32,7 @@ use std::ffi::OsString;
 use std::fs::{self, PathExt};
 use std::io::{self, Read, Write};
 use std::mem;
-use std::path::{Path, PathBuf};
+use std::path::{self, Path, PathBuf};
 use std::process::Command;
 use std::str;
 use flate;
@@ -916,8 +916,9 @@ fn link_args(cmd: &mut Command,
         // stripped away as much as it could. This has not been seen to impact
         // link times negatively.
         //
-        // -dead_strip can't be part of the pre_link_args because it's also used for partial
-        // linking when using multiple codegen units (-r). So we insert it here.
+        // -dead_strip can't be part of the pre_link_args because it's also used
+        // for partial linking when using multiple codegen units (-r). So we
+        // insert it here.
         cmd.arg("-Wl,-dead_strip");
     }
 
@@ -1043,7 +1044,6 @@ fn link_args(cmd: &mut Command,
             has_rpath: sess.target.target.options.has_rpath,
             is_like_osx: sess.target.target.options.is_like_osx,
             get_install_prefix_lib_path: &mut get_install_prefix_lib_path,
-            realpath: &mut ::util::fs::realpath
         };
         cmd.args(&rpath::get_rpath_flags(&mut rpath_config));
     }
@@ -1258,7 +1258,7 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
                 }
             });
         } else {
-            cmd.arg(cratepath);
+            cmd.arg(&fix_windows_verbatim_for_gcc(cratepath));
         }
     }
 
@@ -1271,7 +1271,7 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
         // Just need to tell the linker about where the library lives and
         // what its name is
         if let Some(dir) = cratepath.parent() {
-            cmd.arg("-L").arg(dir);
+            cmd.arg("-L").arg(&fix_windows_verbatim_for_gcc(dir));
         }
         let filestem = cratepath.file_stem().unwrap().to_str().unwrap();
         cmd.arg(&format!("-l{}", unlib(&sess.target, filestem)));
@@ -1325,3 +1325,29 @@ fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
         }
     }
 }
+
+// Unfortunately, on windows, gcc cannot accept paths of the form `\\?\C:\...`
+// (a verbatim path). This form of path is generally pretty rare, but the
+// implementation of `fs::canonicalize` currently generates paths of this form,
+// meaning that we're going to be passing quite a few of these down to gcc.
+//
+// For now we just strip the "verbatim prefix" of `\\?\` from the path. This
+// will probably lose information in some cases, but there's not a whole lot
+// more we can do with a buggy gcc...
+fn fix_windows_verbatim_for_gcc(p: &Path) -> PathBuf {
+    if !cfg!(windows) {
+        return p.to_path_buf()
+    }
+    let mut components = p.components();
+    let prefix = match components.next() {
+        Some(path::Component::Prefix(p)) => p,
+        _ => return p.to_path_buf(),
+    };
+    let disk = match prefix.kind() {
+        path::Prefix::VerbatimDisk(disk) => disk,
+        _ => return p.to_path_buf(),
+    };
+    let mut base = OsString::from(format!("{}:", disk as char));
+    base.push(components.as_path());
+    PathBuf::from(base)
+}