Auto merge of #23292 - alexcrichton:stabilize-io, r=aturon

The new `std::io` module has had some time to bake now, and this commit
stabilizes its functionality. There are still portions of the module which
remain unstable, and below contains a summart of the actions taken.

This commit also deprecates the entire contents of the `old_io` module in a
blanket fashion. All APIs should now have a reasonable replacement in the
new I/O modules.

Stable APIs:

* `std::io` (the name)
* `std::io::prelude` (the name)
* `Read`
* `Read::read`
* `Read::{read_to_end, read_to_string}` after being modified to return a `usize`
  for the number of bytes read.
* `ReadExt`
* `Write`
* `Write::write`
* `Write::{write_all, write_fmt}`
* `WriteExt`
* `BufRead`
* `BufRead::{fill_buf, consume}`
* `BufRead::{read_line, read_until}` after being modified to return a `usize`
  for the number of bytes read.
* `BufReadExt`
* `BufReader`
* `BufReader::{new, with_capacity}`
* `BufReader::{get_ref, get_mut, into_inner}`
* `{Read,BufRead} for BufReader`
* `BufWriter`
* `BufWriter::{new, with_capacity}`
* `BufWriter::{get_ref, get_mut, into_inner}`
* `Write for BufWriter`
* `IntoInnerError`
* `IntoInnerError::{error, into_inner}`
* `{Error,Display} for IntoInnerError`
* `LineWriter`
* `LineWriter::{new, with_capacity}` - `with_capacity` was added
* `LineWriter::{get_ref, get_mut, into_inner}` - `get_mut` was added)
* `Write for LineWriter`
* `BufStream`
* `BufStream::{new, with_capacities}`
* `BufStream::{get_ref, get_mut, into_inner}`
* `{BufRead,Read,Write} for BufStream`
* `stdin`
* `Stdin`
* `Stdin::lock`
* `Stdin::read_line` - added method
* `StdinLock`
* `Read for Stdin`
* `{Read,BufRead} for StdinLock`
* `stdout`
* `Stdout`
* `Stdout::lock`
* `StdoutLock`
* `Write for Stdout`
* `Write for StdoutLock`
* `stderr`
* `Stderr`
* `Stderr::lock`
* `StderrLock`
* `Write for Stderr`
* `Write for StderrLock`
* `io::Result`
* `io::Error`
* `io::Error::last_os_error`
* `{Display, Error} for Error`

Unstable APIs:

(reasons can be found in the commit itself)

* `Write::flush`
* `Seek`
* `ErrorKind`
* `Error::new`
* `Error::from_os_error`
* `Error::kind`

Deprecated APIs

* `Error::description` - available via the `Error` trait
* `Error::detail` - available via the `Display` implementation
* `thread::Builder::{stdout, stderr}`

Changes in functionality:

* `old_io::stdio::set_stderr` is now a noop as the infrastructure for printing
  backtraces has migrated to `std::io`.

[breaking-change]

1 files changed, 5 insertions, 4 deletions

diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 3266da5eb31..d332556d188 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -22,7 +22,7 @@ use io;
 use iter;
 use libc::{self, c_int, c_char, c_void};
 use mem;
-use old_io::{IoError, IoResult};
+#[allow(deprecated)] use old_io::{IoError, IoResult};
 use ptr;
 use path::{self, PathBuf};
 use slice;
@@ -398,7 +398,7 @@ pub fn env() -> Env {
         let mut environ = *environ();
         if environ as usize == 0 {
             panic!("os::env() failure getting env string from OS: {}",
-                   IoError::last_error());
+                   io::Error::last_os_error());
         }
         let mut result = Vec::new();
         while *environ != ptr::null() {
@@ -434,7 +434,7 @@ pub fn setenv(k: &OsStr, v: &OsStr) {
         let k = k.to_cstring().unwrap();
         let v = v.to_cstring().unwrap();
         if libc::funcs::posix01::unistd::setenv(k.as_ptr(), v.as_ptr(), 1) != 0 {
-            panic!("failed setenv: {}", IoError::last_error());
+            panic!("failed setenv: {}", io::Error::last_os_error());
         }
     }
 }
@@ -443,11 +443,12 @@ pub fn unsetenv(n: &OsStr) {
     unsafe {
         let nbuf = n.to_cstring().unwrap();
         if libc::funcs::posix01::unistd::unsetenv(nbuf.as_ptr()) != 0 {
-            panic!("failed unsetenv: {}", IoError::last_error());
+            panic!("failed unsetenv: {}", io::Error::last_os_error());
         }
     }
 }
 
+#[allow(deprecated)]
 pub unsafe fn pipe() -> IoResult<(FileDesc, FileDesc)> {
     let mut fds = [0; 2];
     if libc::pipe(fds.as_mut_ptr()) == 0 {