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]

2 files changed, 17 insertions, 14 deletions

diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 6fc56522c6a..d0ef89e811b 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -199,15 +199,17 @@ use self::DecoderError::*;
 use self::ParserState::*;
 use self::InternalStackElement::*;
 
-use std;
 use std::collections::{HashMap, BTreeMap};
-use std::{char, f64, fmt, old_io, num, str};
+use std::io::prelude::*;
+use std::io;
 use std::mem::{swap};
-use std::num::{Float, Int};
 use std::num::FpCategory as Fp;
+use std::num::{Float, Int};
+use std::ops::Index;
 use std::str::FromStr;
 use std::string;
-use std::ops::Index;
+use std::{char, f64, fmt, num, str};
+use std;
 use unicode::str as unicode_str;
 use unicode::str::Utf16Item;
 
@@ -256,11 +258,11 @@ pub enum ErrorCode {
     NotUtf8,
 }
 
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Debug)]
 pub enum ParserError {
     /// msg, line, col
     SyntaxError(ErrorCode, uint, uint),
-    IoError(old_io::IoErrorKind, &'static str),
+    IoError(io::ErrorKind, String),
 }
 
 // Builder and Parser have the same errors.
@@ -331,8 +333,8 @@ impl fmt::Display for ErrorCode {
     }
 }
 
-fn io_error_to_error(io: old_io::IoError) -> ParserError {
-    IoError(io.kind, io.desc)
+fn io_error_to_error(io: io::Error) -> ParserError {
+    IoError(io.kind(), io.to_string())
 }
 
 impl fmt::Display for ParserError {
@@ -1982,7 +1984,7 @@ impl<T: Iterator<Item=char>> Builder<T> {
         self.bump();
         match self.token {
             None => {}
-            Some(Error(e)) => { return Err(e); }
+            Some(Error(ref e)) => { return Err(e.clone()); }
             ref tok => { panic!("unexpected token {:?}", tok.clone()); }
         }
         result
@@ -2004,7 +2006,7 @@ impl<T: Iterator<Item=char>> Builder<T> {
                 swap(s, &mut temp);
                 Ok(Json::String(temp))
             }
-            Some(Error(e)) => Err(e),
+            Some(Error(ref e)) => Err(e.clone()),
             Some(ArrayStart) => self.build_array(),
             Some(ObjectStart) => self.build_object(),
             Some(ObjectEnd) => self.parser.error(InvalidSyntax),
@@ -2037,7 +2039,7 @@ impl<T: Iterator<Item=char>> Builder<T> {
         loop {
             match self.token {
                 Some(ObjectEnd) => { return Ok(Json::Object(values)); }
-                Some(Error(e)) => { return Err(e); }
+                Some(Error(ref e)) => { return Err(e.clone()); }
                 None => { break; }
                 _ => {}
             }
@@ -2056,8 +2058,9 @@ impl<T: Iterator<Item=char>> Builder<T> {
 }
 
 /// Decodes a json value from an `&mut old_io::Reader`
-pub fn from_reader(rdr: &mut old_io::Reader) -> Result<Json, BuilderError> {
-    let contents = match rdr.read_to_end() {
+pub fn from_reader(rdr: &mut Read) -> Result<Json, BuilderError> {
+    let mut contents = Vec::new();
+    match rdr.read_to_end(&mut contents) {
         Ok(c)  => c,
         Err(e) => return Err(io_error_to_error(e))
     };
diff --git a/src/libserialize/lib.rs b/src/libserialize/lib.rs
index 8d58ba99e13..49e44a6d455 100644
--- a/src/libserialize/lib.rs
+++ b/src/libserialize/lib.rs
@@ -31,7 +31,7 @@ Core encoding and decoding interfaces.
 #![feature(collections)]
 #![feature(core)]
 #![feature(int_uint)]
-#![feature(old_io)]
+#![feature(io)]
 #![feature(old_path)]
 #![feature(rustc_private)]
 #![feature(staged_api)]