std: Add io module again

src/libstd/io/error.rs

@@ -0,0 +1,183 @@
+// 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 boxed::Box;
+use clone::Clone;
+use error::Error as StdError;
+use fmt;
+use option::Option::{self, Some, None};
+use result;
+use string::String;
+use sys;
+
+/// A type for results generated by I/O related functions where the `Err` type
+/// is hard-wired to `io::Error`.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `std::result::Result`.
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// `ErrorKind`.
+#[derive(PartialEq, Eq, Clone, Debug)]
+pub struct Error {
+    repr: Repr,
+}
+
+#[derive(PartialEq, Eq, Clone, Debug)]
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(PartialEq, Eq, Clone, Debug)]
+struct Custom {
+    kind: ErrorKind,
+    desc: &'static str,
+    detail: Option<String>
+}
+
+/// A list specifying general categories of I/O error.
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+pub enum ErrorKind {
+    /// The file was not found.
+    FileNotFound,
+    /// The file permissions disallowed access to this file.
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    NotConnected,
+    /// The operation failed because a pipe was closed.
+    BrokenPipe,
+    /// A file already existed with that name.
+    PathAlreadyExists,
+    /// No file exists at that location.
+    PathDoesntExist,
+    /// The path did not specify the type of file that this operation required.
+    /// For example, attempting to copy a directory with the `fs::copy()`
+    /// operation will fail with this error.
+    MismatchedFileTypeForOperation,
+    /// The operation temporarily failed (for example, because a signal was
+    /// received), and retrying may succeed.
+    ResourceUnavailable,
+    /// A parameter was incorrect in a way that caused an I/O error not part of
+    /// this list.
+    InvalidInput,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    WriteZero,
+    /// This operation was interrupted
+    Interrupted,
+    /// Any I/O error not part of this list.
+    Other,
+}
+
+impl Error {
+    /// Creates a new custom error from a specified kind/description/detail.
+    pub fn new(kind: ErrorKind,
+               description: &'static str,
+               detail: Option<String>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                desc: description,
+                detail: detail,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    pub fn last_os_error() -> Error {
+        Error::from_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    pub fn from_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Return the corresponding `ErrorKind` for this error.
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+
+    /// Returns a short description for this error message
+    pub fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => "os error",
+            Repr::Custom(ref c) => c.desc,
+        }
+    }
+
+    /// Returns a detailed error message for this error (if one is available)
+    pub fn detail(&self) -> Option<String> {
+        match self.repr {
+            Repr::Os(code) => Some(sys::os::error_string(code)),
+            Repr::Custom(ref s) => s.detail.clone(),
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => {
+                match **c {
+                    Custom {
+                        kind: ErrorKind::Other,
+                        desc: "unknown error",
+                        detail: Some(ref detail)
+                    } => {
+                        write!(fmt, "{}", detail)
+                    }
+                    Custom { detail: None, desc, .. } =>
+                        write!(fmt, "{}", desc),
+                    Custom { detail: Some(ref detail), desc, .. } =>
+                        write!(fmt, "{} ({})", desc, detail)
+                }
+            }
+        }
+    }
+}
+
+impl StdError for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => "os error",
+            Repr::Custom(ref c) => c.desc,
+        }
+    }
+}

src/libstd/io/impls.rs

@@ -0,0 +1,88 @@
+// 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 core::prelude::*;
+
+use boxed::Box;
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead};
+use mem;
+use slice;
+use vec::Vec;
+
+// =============================================================================
+// Forwarding implementations
+
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { (**self).read(buf) }
+}
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+}
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+}
+
+impl<R: Read + ?Sized> Read for Box<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { (**self).read(buf) }
+}
+impl<W: Write + ?Sized> Write for Box<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+}
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+impl<'a> Read for &'a [u8] {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        slice::bytes::copy_memory(buf, a);
+        *self = b;
+        Ok(amt)
+    }
+}
+
+impl<'a> BufRead for &'a [u8] {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+impl<'a> Write for &'a mut [u8] {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        slice::bytes::copy_memory(a, &data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+impl Write for Vec<u8> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.push_all(buf);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}