std: Implement stdio for `std::io`

This is an implementation of RFC 899 and adds stdio functionality to the new
`std::io` module. Details of the API can be found on the RFC, but from a high
level:

* `io::{stdin, stdout, stderr}` constructors are now available. There are also
  `*_raw` variants for unbuffered and unlocked access.
* All handles are globally shared (excluding raw variants).
* The stderr handle is no longer buffered.
* All handles can be explicitly locked (excluding the raw variants).

The `print!` and `println!` machinery has not yet been hooked up to these
streams just yet. The `std::fmt::output` module has also not yet been
implemented as part of this commit.

4 files changed, 171 insertions, 2 deletions

diff --git a/src/libstd/sys/windows/c.rs b/src/libstd/sys/windows/c.rs
index 2d1a5e10bd6..8ed7302b665 100644
--- a/src/libstd/sys/windows/c.rs
+++ b/src/libstd/sys/windows/c.rs
@@ -48,6 +48,11 @@ pub const WSAESHUTDOWN: libc::c_int = 10058;
 pub const ERROR_NO_MORE_FILES: libc::DWORD = 18;
 pub const TOKEN_READ: libc::DWORD = 0x20008;
 
+// Note that these are not actually HANDLEs, just values to pass to GetStdHandle
+pub const STD_INPUT_HANDLE: libc::DWORD = -10;
+pub const STD_OUTPUT_HANDLE: libc::DWORD = -11;
+pub const STD_ERROR_HANDLE: libc::DWORD = -12;
+
 #[repr(C)]
 #[cfg(target_arch = "x86")]
 pub struct WSADATA {
@@ -427,6 +432,7 @@ extern "system" {
                             DesiredAccess: libc::DWORD,
                             TokenHandle: *mut libc::HANDLE) -> libc::BOOL;
     pub fn GetCurrentProcess() -> libc::HANDLE;
+    pub fn GetStdHandle(which: libc::DWORD) -> libc::HANDLE;
 }
 
 #[link(name = "userenv")]
diff --git a/src/libstd/sys/windows/handle.rs b/src/libstd/sys/windows/handle.rs
index 99de659be41..0089dcad455 100644
--- a/src/libstd/sys/windows/handle.rs
+++ b/src/libstd/sys/windows/handle.rs
@@ -10,9 +10,10 @@
 
 use prelude::v1::*;
 
-use libc::{self, HANDLE};
-use io;
 use io::ErrorKind;
+use io;
+use libc::{self, HANDLE};
+use mem;
 use ptr;
 use sys::cvt;
 
@@ -28,6 +29,12 @@ impl Handle {
 
     pub fn raw(&self) -> HANDLE { self.0 }
 
+    pub fn into_raw(self) -> HANDLE {
+        let ret = self.0;
+        unsafe { mem::forget(self) }
+        return ret;
+    }
+
     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
         read(self.0, buf)
     }
diff --git a/src/libstd/sys/windows/mod.rs b/src/libstd/sys/windows/mod.rs
index 5bb2a134533..3bdadbb9012 100644
--- a/src/libstd/sys/windows/mod.rs
+++ b/src/libstd/sys/windows/mod.rs
@@ -61,6 +61,7 @@ pub mod time;
 pub mod timer;
 pub mod tty;
 pub mod udp;
+pub mod stdio;
 
 pub mod addrinfo {
     pub use sys_common::net::get_host_addresses;
diff --git a/src/libstd/sys/windows/stdio.rs b/src/libstd/sys/windows/stdio.rs
new file mode 100644
index 00000000000..72ce8b7c6e3
--- /dev/null
+++ b/src/libstd/sys/windows/stdio.rs
@@ -0,0 +1,155 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use io::{self, Cursor};
+use iter::repeat;
+use libc;
+use ptr;
+use str;
+use sync::Mutex;
+use sys::c;
+use sys::cvt;
+use sys::handle::Handle;
+
+struct NoClose(Option<Handle>);
+
+enum Output {
+    Console(NoClose),
+    Pipe(NoClose),
+}
+
+pub struct Stdin {
+    handle: Output,
+    utf8: Mutex<io::Cursor<Vec<u8>>>,
+}
+pub struct Stdout(Output);
+pub struct Stderr(Output);
+
+fn get(handle: libc::DWORD) -> io::Result<Output> {
+    let handle = unsafe { c::GetStdHandle(handle) };
+    if handle == libc::INVALID_HANDLE_VALUE {
+        Err(io::Error::last_os_error())
+    } else if handle.is_null() {
+        Err(io::Error::new(io::ErrorKind::Other,
+                           "no stdio handle available for this process", None))
+    } else {
+        let ret = NoClose::new(handle);
+        let mut out = 0;
+        match unsafe { c::GetConsoleMode(handle, &mut out) } {
+            0 => Ok(Output::Pipe(ret)),
+            _ => Ok(Output::Console(ret)),
+        }
+    }
+}
+
+fn write(out: &Output, data: &[u8]) -> io::Result<usize> {
+    let handle = match *out {
+        Output::Console(ref c) => c.get().raw(),
+        Output::Pipe(ref p) => return p.get().write(data),
+    };
+    let utf16 = match str::from_utf8(data).ok() {
+        Some(utf8) => utf8.utf16_units().collect::<Vec<u16>>(),
+        None => return Err(invalid_encoding()),
+    };
+    let mut written = 0;
+    try!(cvt(unsafe {
+        c::WriteConsoleW(handle,
+                         utf16.as_ptr() as libc::LPCVOID,
+                         utf16.len() as u32,
+                         &mut written,
+                         ptr::null_mut())
+    }));
+
+    // FIXME if this only partially writes the utf16 buffer then we need to
+    //       figure out how many bytes of `data` were actually written
+    assert_eq!(written as usize, utf16.len());
+    Ok(data.len())
+}
+
+impl Stdin {
+    pub fn new() -> Stdin {
+        Stdin {
+            handle: get(c::STD_INPUT_HANDLE).unwrap(),
+            utf8: Mutex::new(Cursor::new(Vec::new())),
+        }
+    }
+
+    pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
+        let handle = match self.handle {
+            Output::Console(ref c) => c.get().raw(),
+            Output::Pipe(ref p) => return p.get().read(buf),
+        };
+        let mut utf8 = self.utf8.lock().unwrap();
+        // Read more if the buffer is empty
+        if utf8.position() as usize == utf8.get_ref().len() {
+            let mut utf16: Vec<u16> = repeat(0u16).take(0x1000).collect();
+            let mut num = 0;
+            try!(cvt(unsafe {
+                c::ReadConsoleW(handle,
+                                utf16.as_mut_ptr() as libc::LPVOID,
+                                utf16.len() as u32,
+                                &mut num,
+                                ptr::null_mut())
+            }));
+            utf16.truncate(num as usize);
+            // FIXME: what to do about this data that has already been read?
+            let data = match String::from_utf16(&utf16) {
+                Ok(utf8) => utf8.into_bytes(),
+                Err(..) => return Err(invalid_encoding()),
+            };
+            *utf8 = Cursor::new(data);
+        }
+
+        // MemReader shouldn't error here since we just filled it
+        utf8.read(buf)
+    }
+}
+
+impl Stdout {
+    pub fn new() -> Stdout {
+        Stdout(get(c::STD_OUTPUT_HANDLE).unwrap())
+    }
+
+    pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        write(&self.0, data)
+    }
+}
+
+impl Stderr {
+    pub fn new() -> Stderr {
+        Stderr(get(c::STD_ERROR_HANDLE).unwrap())
+    }
+
+    pub fn write(&self, data: &[u8]) -> io::Result<usize> {
+        write(&self.0, data)
+    }
+}
+
+impl NoClose {
+    fn new(handle: libc::HANDLE) -> NoClose {
+        NoClose(Some(Handle::new(handle)))
+    }
+
+    fn get(&self) -> &Handle { self.0.as_ref().unwrap() }
+}
+
+impl Drop for NoClose {
+    fn drop(&mut self) {
+        self.0.take().unwrap().into_raw();
+    }
+}
+
+fn invalid_encoding() -> io::Error {
+    io::Error::new(io::ErrorKind::InvalidInput, "text was not valid unicode",
+                   None)
+}