From 5fbb0949a53a6ac51c6d9b187ef4c464e52ae536 Mon Sep 17 00:00:00 2001 From: Brian Anderson Date: Mon, 22 Apr 2013 14:52:40 -0700 Subject: [PATCH] core::rt: Add implementations of Reader, Writer, and Listener for Option These will make it easier to write I/O code without worrying about errors --- src/libcore/rt/io/mod.rs | 24 +++++- src/libcore/rt/io/option.rs | 153 ++++++++++++++++++++++++++++++++++++ 2 files changed, 174 insertions(+), 3 deletions(-) create mode 100644 src/libcore/rt/io/option.rs diff --git a/src/libcore/rt/io/mod.rs b/src/libcore/rt/io/mod.rs index f1b248c6e1d7..d9d6622277f7 100644 --- a/src/libcore/rt/io/mod.rs +++ b/src/libcore/rt/io/mod.rs @@ -152,6 +152,9 @@ pub mod mem; /// Non-blocking access to stdin, stdout, stderr pub mod stdio; +/// Implementations for Option +mod option; + /// Basic stream compression. XXX: Belongs with other flate code #[cfg(not(stage0))] // XXX Using unsnapshotted features pub mod flate; @@ -194,12 +197,14 @@ pub struct IoError { detail: Option<~str> } +#[deriving(Eq)] pub enum IoErrorKind { FileNotFound, FilePermission, ConnectionFailed, Closed, - OtherIoError + OtherIoError, + PreviousIoError } // XXX: Can't put doc comments on macros @@ -232,9 +237,9 @@ pub trait Reader { /// println(reader.read_line()); /// } /// - /// # XXX + /// # Failue /// - /// What does this return if the Reader is in an error state? + /// Returns `true` on failure. fn eof(&mut self) -> bool; } @@ -323,3 +328,16 @@ pub trait Decorator { /// Take a mutable reference to the decorated value fn inner_mut_ref<'a>(&'a mut self) -> &'a mut T; } + +pub fn standard_error(kind: IoErrorKind) -> IoError { + match kind { + PreviousIoError => { + IoError { + kind: PreviousIoError, + desc: "Failing due to a previous I/O error", + detail: None + } + } + _ => fail!() + } +} diff --git a/src/libcore/rt/io/option.rs b/src/libcore/rt/io/option.rs new file mode 100644 index 000000000000..95f8711cb5bd --- /dev/null +++ b/src/libcore/rt/io/option.rs @@ -0,0 +1,153 @@ +// Copyright 2013 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! Implementations of I/O traits for the Option type +//! +//! I/O constructors return option types to allow errors to be handled. +//! These implementations allow e.g. `Option` to be used +//! as a `Reader` without unwrapping the option first. +//! +//! # XXX Seek and Close + +use option::*; +use super::{Reader, Writer, Listener}; +use super::{standard_error, PreviousIoError, io_error, IoError}; + +fn prev_io_error() -> IoError { + standard_error(PreviousIoError) +} + +impl Writer for Option { + fn write(&mut self, buf: &[u8]) { + match *self { + Some(ref mut writer) => writer.write(buf), + None => io_error::cond.raise(prev_io_error()) + } + } + + fn flush(&mut self) { + match *self { + Some(ref mut writer) => writer.flush(), + None => io_error::cond.raise(prev_io_error()) + } + } +} + +impl Reader for Option { + fn read(&mut self, buf: &mut [u8]) -> Option { + match *self { + Some(ref mut reader) => reader.read(buf), + None => { + io_error::cond.raise(prev_io_error()); + None + } + } + } + + fn eof(&mut self) -> bool { + match *self { + Some(ref mut reader) => reader.eof(), + None => { + io_error::cond.raise(prev_io_error()); + true + } + } + } +} + +impl, S> Listener for Option { + fn accept(&mut self) -> Option { + match *self { + Some(ref mut listener) => listener.accept(), + None => { + io_error::cond.raise(prev_io_error()); + None + } + } + } +} + +#[cfg(test)] +mod test { + use option::*; + use super::super::mem::*; + use rt::test::*; + use super::super::{PreviousIoError, io_error}; + + #[test] + fn test_option_writer() { + do run_in_newsched_task { + let mut writer: Option = Some(MemWriter::new()); + writer.write([0, 1, 2]); + writer.flush(); + assert!(writer.unwrap().inner() == ~[0, 1, 2]); + } + } + + #[test] + fn test_option_writer_error() { + do run_in_newsched_task { + let mut writer: Option = None; + + let mut called = false; + do io_error::cond.trap(|err| { + assert!(err.kind == PreviousIoError); + called = true; + }).in { + writer.write([0, 0, 0]); + } + assert!(called); + + let mut called = false; + do io_error::cond.trap(|err| { + assert!(err.kind == PreviousIoError); + called = true; + }).in { + writer.flush(); + } + assert!(called); + } + } + + #[test] + fn test_option_reader() { + do run_in_newsched_task { + let mut reader: Option = Some(MemReader::new(~[0, 1, 2, 3])); + let mut buf = [0, 0]; + reader.read(buf); + assert!(buf == [0, 1]); + assert!(!reader.eof()); + } + } + + #[test] + fn test_option_reader_error() { + let mut reader: Option = None; + let mut buf = []; + + let mut called = false; + do io_error::cond.trap(|err| { + assert!(err.kind == PreviousIoError); + called = true; + }).in { + reader.read(buf); + } + assert!(called); + + let mut called = false; + do io_error::cond.trap(|err| { + assert!(err.kind == PreviousIoError); + called = true; + }).in { + assert!(reader.eof()); + } + assert!(called); + } +}