forked from M-Labs/zynq-rs
2665 lines
86 KiB
Rust
2665 lines
86 KiB
Rust
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//! Traits, helpers, and type definitions for core I/O functionality.
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//!
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//! The `std::io` module contains a number of common things you'll need
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//! when doing input and output. The most core part of this module is
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//! the [`Read`] and [`Write`] traits, which provide the
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//! most general interface for reading and writing input and output.
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//!
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//! # Read and Write
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//!
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//! Because they are traits, [`Read`] and [`Write`] are implemented by a number
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//! of other types, and you can implement them for your types too. As such,
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//! you'll see a few different types of I/O throughout the documentation in
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//! this module: [`File`]s, [`TcpStream`]s, and sometimes even [`Vec<T>`]s. For
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//! example, [`Read`] adds a [`read`][`Read::read`] method, which we can use on
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//! [`File`]s:
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//!
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//! ```no_run
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//! use std::io;
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//! use std::io::prelude::*;
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//! use std::fs::File;
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//!
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//! fn main() -> io::Result<()> {
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//! let mut f = File::open("foo.txt")?;
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//! let mut buffer = [0; 10];
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//!
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//! // read up to 10 bytes
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//! let n = f.read(&mut buffer)?;
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//!
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//! println!("The bytes: {:?}", &buffer[..n]);
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//! Ok(())
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//! }
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//! ```
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//!
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//! [`Read`] and [`Write`] are so important, implementors of the two traits have a
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//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
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//! of 'a type that implements the [`Read`] trait'. Much easier!
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//!
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//! ## Seek and BufRead
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//!
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//! Beyond that, there are two important traits that are provided: [`Seek`]
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//! and [`BufRead`]. Both of these build on top of a reader to control
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//! how the reading happens. [`Seek`] lets you control where the next byte is
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//! coming from:
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//!
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//! ```no_run
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//! use std::io;
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//! use std::io::prelude::*;
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//! use std::io::SeekFrom;
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//! use std::fs::File;
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//!
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//! fn main() -> io::Result<()> {
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//! let mut f = File::open("foo.txt")?;
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//! let mut buffer = [0; 10];
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//!
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//! // skip to the last 10 bytes of the file
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//! f.seek(SeekFrom::End(-10))?;
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//!
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//! // read up to 10 bytes
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//! let n = f.read(&mut buffer)?;
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//!
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//! println!("The bytes: {:?}", &buffer[..n]);
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//! Ok(())
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//! }
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//! ```
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//!
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//! [`BufRead`] uses an internal buffer to provide a number of other ways to read, but
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//! to show it off, we'll need to talk about buffers in general. Keep reading!
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//!
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//! ## BufReader and BufWriter
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//!
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//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
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//! making near-constant calls to the operating system. To help with this,
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//! `std::io` comes with two structs, [`BufReader`] and [`BufWriter`], which wrap
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//! readers and writers. The wrapper uses a buffer, reducing the number of
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//! calls and providing nicer methods for accessing exactly what you want.
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//!
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//! For example, [`BufReader`] works with the [`BufRead`] trait to add extra
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//! methods to any reader:
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//!
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//! ```no_run
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//! use std::io;
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//! use std::io::prelude::*;
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//! use std::io::BufReader;
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//! use std::fs::File;
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//!
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//! fn main() -> io::Result<()> {
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//! let f = File::open("foo.txt")?;
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//! let mut reader = BufReader::new(f);
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//! let mut buffer = String::new();
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//!
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//! // read a line into buffer
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//! reader.read_line(&mut buffer)?;
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//!
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//! println!("{}", buffer);
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//! Ok(())
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//! }
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//! ```
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//!
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//! [`BufWriter`] doesn't add any new ways of writing; it just buffers every call
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//! to [`write`][`Write::write`]:
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//!
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//! ```no_run
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//! use std::io;
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//! use std::io::prelude::*;
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//! use std::io::BufWriter;
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//! use std::fs::File;
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//!
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//! fn main() -> io::Result<()> {
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//! let f = File::create("foo.txt")?;
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//! {
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//! let mut writer = BufWriter::new(f);
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//!
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//! // write a byte to the buffer
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//! writer.write(&[42])?;
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//!
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//! } // the buffer is flushed once writer goes out of scope
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//!
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//! Ok(())
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//! }
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//! ```
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//!
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//! ## Standard input and output
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//!
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//! A very common source of input is standard input:
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//!
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//! ```no_run
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//! use std::io;
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//!
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//! fn main() -> io::Result<()> {
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//! let mut input = String::new();
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//!
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//! io::stdin().read_line(&mut input)?;
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//!
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//! println!("You typed: {}", input.trim());
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//! Ok(())
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//! }
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//! ```
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//!
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//! Note that you cannot use the [`?` operator] in functions that do not return
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//! a [`Result<T, E>`][`Result`]. Instead, you can call [`.unwrap()`]
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//! or `match` on the return value to catch any possible errors:
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//!
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//! ```no_run
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//! use std::io;
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//!
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//! let mut input = String::new();
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//!
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//! io::stdin().read_line(&mut input).unwrap();
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//! ```
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//!
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//! And a very common source of output is standard output:
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//!
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//! ```no_run
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//! use std::io;
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//! use std::io::prelude::*;
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//!
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//! fn main() -> io::Result<()> {
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//! io::stdout().write(&[42])?;
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//! Ok(())
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//! }
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//! ```
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//!
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//! Of course, using [`io::stdout`] directly is less common than something like
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//! [`println!`].
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//!
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//! ## Iterator types
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//!
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//! A large number of the structures provided by `std::io` are for various
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//! ways of iterating over I/O. For example, [`Lines`] is used to split over
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//! lines:
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//!
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//! ```no_run
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//! use std::io;
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//! use std::io::prelude::*;
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//! use std::io::BufReader;
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//! use std::fs::File;
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//!
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//! fn main() -> io::Result<()> {
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//! let f = File::open("foo.txt")?;
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//! let reader = BufReader::new(f);
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//!
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//! for line in reader.lines() {
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//! println!("{}", line?);
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//! }
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//! Ok(())
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//! }
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//! ```
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//!
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//! ## Functions
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//!
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//! There are a number of [functions][functions-list] that offer access to various
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//! features. For example, we can use three of these functions to copy everything
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//! from standard input to standard output:
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//!
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//! ```no_run
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//! use std::io;
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//!
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//! fn main() -> io::Result<()> {
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//! io::copy(&mut io::stdin(), &mut io::stdout())?;
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//! Ok(())
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//! }
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//! ```
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//!
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//! [functions-list]: #functions-1
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//!
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//! ## io::Result
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//!
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//! Last, but certainly not least, is [`io::Result`]. This type is used
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//! as the return type of many `std::io` functions that can cause an error, and
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//! can be returned from your own functions as well. Many of the examples in this
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//! module use the [`?` operator]:
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//!
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//! ```
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//! use std::io;
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//!
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//! fn read_input() -> io::Result<()> {
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//! let mut input = String::new();
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//!
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//! io::stdin().read_line(&mut input)?;
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//!
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//! println!("You typed: {}", input.trim());
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//!
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//! Ok(())
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//! }
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//! ```
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//!
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//! The return type of `read_input()`, [`io::Result<()>`][`io::Result`], is a very
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//! common type for functions which don't have a 'real' return value, but do want to
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//! return errors if they happen. In this case, the only purpose of this function is
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//! to read the line and print it, so we use `()`.
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//!
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//! ## Platform-specific behavior
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//!
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//! Many I/O functions throughout the standard library are documented to indicate
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//! what various library or syscalls they are delegated to. This is done to help
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//! applications both understand what's happening under the hood as well as investigate
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//! any possibly unclear semantics. Note, however, that this is informative, not a binding
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//! contract. The implementation of many of these functions are subject to change over
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//! time and may call fewer or more syscalls/library functions.
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//!
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//! [`Read`]: trait.Read.html
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//! [`Write`]: trait.Write.html
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//! [`Seek`]: trait.Seek.html
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//! [`BufRead`]: trait.BufRead.html
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//! [`File`]: ../fs/struct.File.html
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//! [`TcpStream`]: ../net/struct.TcpStream.html
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//! [`Vec<T>`]: ../vec/struct.Vec.html
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//! [`BufReader`]: struct.BufReader.html
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//! [`BufWriter`]: struct.BufWriter.html
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//! [`Write::write`]: trait.Write.html#tymethod.write
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//! [`io::stdout`]: fn.stdout.html
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//! [`println!`]: ../macro.println.html
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//! [`Lines`]: struct.Lines.html
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//! [`io::Result`]: type.Result.html
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//! [`?` operator]: ../../book/appendix-02-operators.html
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//! [`Read::read`]: trait.Read.html#tymethod.read
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//! [`Result`]: ../result/enum.Result.html
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//! [`.unwrap()`]: ../result/enum.Result.html#method.unwrap
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use core::cmp;
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use core::fmt;
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use core::ptr;
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use core::slice;
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use core::str;
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#[cfg(feature="collections")] pub use self::buffered::IntoInnerError;
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#[cfg(feature="collections")] pub use self::buffered::{BufReader, BufWriter, LineWriter};
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pub use self::cursor::Cursor;
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pub use self::error::{Error, ErrorKind, Result};
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pub use self::util::{copy, empty, repeat, sink, Empty, Repeat, Sink};
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#[cfg(feature="collections")] mod buffered;
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mod cursor;
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mod error;
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mod impls;
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pub mod prelude;
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mod util;
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#[cfg(feature="collections")]
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use collections::{
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vec::Vec,
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string::String,
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};
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const DEFAULT_BUF_SIZE: usize = 8 * 1024;
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#[cfg(feature="collections")]
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struct Guard<'a> {
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buf: &'a mut Vec<u8>,
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len: usize,
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}
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#[cfg(feature="collections")]
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impl Drop for Guard<'_> {
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fn drop(&mut self) {
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unsafe {
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self.buf.set_len(self.len);
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}
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}
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}
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// A few methods below (read_to_string, read_line) will append data into a
|
||
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// `String` buffer, but we need to be pretty careful when doing this. The
|
||
|
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// implementation will just call `.as_mut_vec()` and then delegate to a
|
||
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// byte-oriented reading method, but we must ensure that when returning we never
|
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// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
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//
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|
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// To this end, we use an RAII guard (to protect against panics) which updates
|
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// the length of the string when it is dropped. This guard initially truncates
|
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// the string to the prior length and only after we've validated that the
|
||
|
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// new contents are valid UTF-8 do we allow it to set a longer length.
|
||
|
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//
|
||
|
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// The unsafety in this function is twofold:
|
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|
|
//
|
||
|
|
// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
|
||
|
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// checks.
|
||
|
|
// 2. We're passing a raw buffer to the function `f`, and it is expected that
|
||
|
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// the function only *appends* bytes to the buffer. We'll get undefined
|
||
|
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// behavior if existing bytes are overwritten to have non-UTF-8 data.
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
|
||
|
|
where
|
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|
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F: FnOnce(&mut Vec<u8>) -> Result<usize>,
|
||
|
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{
|
||
|
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unsafe {
|
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|
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let mut g = Guard { len: buf.len(), buf: buf.as_mut_vec() };
|
||
|
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let ret = f(g.buf);
|
||
|
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if str::from_utf8(&g.buf[g.len..]).is_err() {
|
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|
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ret.and_then(|_| {
|
||
|
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Err(Error::new(ErrorKind::InvalidData, "stream did not contain valid UTF-8"))
|
||
|
|
})
|
||
|
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} else {
|
||
|
|
g.len = g.buf.len();
|
||
|
|
ret
|
||
|
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}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// This uses an adaptive system to extend the vector when it fills. We want to
|
||
|
|
// avoid paying to allocate and zero a huge chunk of memory if the reader only
|
||
|
|
// has 4 bytes while still making large reads if the reader does have a ton
|
||
|
|
// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
|
||
|
|
// time is 4,500 times (!) slower than a default reservation size of 32 if the
|
||
|
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// reader has a very small amount of data to return.
|
||
|
|
//
|
||
|
|
// Because we're extending the buffer with uninitialized data for trusted
|
||
|
|
// readers, we need to make sure to truncate that if any of this panics.
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
|
||
|
|
read_to_end_with_reservation(r, buf, |_| 32)
|
||
|
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}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn read_to_end_with_reservation<R, F>(
|
||
|
|
r: &mut R,
|
||
|
|
buf: &mut Vec<u8>,
|
||
|
|
mut reservation_size: F,
|
||
|
|
) -> Result<usize>
|
||
|
|
where
|
||
|
|
R: Read + ?Sized,
|
||
|
|
F: FnMut(&R) -> usize,
|
||
|
|
{
|
||
|
|
let start_len = buf.len();
|
||
|
|
let mut g = Guard { len: buf.len(), buf };
|
||
|
|
let ret;
|
||
|
|
loop {
|
||
|
|
if g.len == g.buf.len() {
|
||
|
|
unsafe {
|
||
|
|
// FIXME(danielhenrymantilla): #42788
|
||
|
|
//
|
||
|
|
// - This creates a (mut) reference to a slice of
|
||
|
|
// _uninitialized_ integers, which is **undefined behavior**
|
||
|
|
//
|
||
|
|
// - Only the standard library gets to soundly "ignore" this,
|
||
|
|
// based on its privileged knowledge of unstable rustc
|
||
|
|
// internals;
|
||
|
|
g.buf.reserve(reservation_size(r));
|
||
|
|
let capacity = g.buf.capacity();
|
||
|
|
g.buf.set_len(capacity);
|
||
|
|
r.initializer().initialize(&mut g.buf[g.len..]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
match r.read(&mut g.buf[g.len..]) {
|
||
|
|
Ok(0) => {
|
||
|
|
ret = Ok(g.len - start_len);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
Ok(n) => g.len += n,
|
||
|
|
Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
|
||
|
|
Err(e) => {
|
||
|
|
ret = Err(e);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
ret
|
||
|
|
}
|
||
|
|
|
||
|
|
/// The `Read` trait allows for reading bytes from a source.
|
||
|
|
///
|
||
|
|
/// Implementors of the `Read` trait are called 'readers'.
|
||
|
|
///
|
||
|
|
/// Readers are defined by one required method, [`read()`]. Each call to [`read()`]
|
||
|
|
/// will attempt to pull bytes from this source into a provided buffer. A
|
||
|
|
/// number of other methods are implemented in terms of [`read()`], giving
|
||
|
|
/// implementors a number of ways to read bytes while only needing to implement
|
||
|
|
/// a single method.
|
||
|
|
///
|
||
|
|
/// Readers are intended to be composable with one another. Many implementors
|
||
|
|
/// throughout [`std::io`] take and provide types which implement the `Read`
|
||
|
|
/// trait.
|
||
|
|
///
|
||
|
|
/// Please note that each call to [`read()`] may involve a system call, and
|
||
|
|
/// therefore, using something that implements [`BufRead`], such as
|
||
|
|
/// [`BufReader`], will be more efficient.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = [0; 10];
|
||
|
|
///
|
||
|
|
/// // read up to 10 bytes
|
||
|
|
/// f.read(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// let mut buffer = Vec::new();
|
||
|
|
/// // read the whole file
|
||
|
|
/// f.read_to_end(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// // read into a String, so that you don't need to do the conversion.
|
||
|
|
/// let mut buffer = String::new();
|
||
|
|
/// f.read_to_string(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// // and more! See the other methods for more details.
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// Read from [`&str`] because [`&[u8]`][slice] implements `Read`:
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// # use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut b = "This string will be read".as_bytes();
|
||
|
|
/// let mut buffer = [0; 10];
|
||
|
|
///
|
||
|
|
/// // read up to 10 bytes
|
||
|
|
/// b.read(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// // etc... it works exactly as a File does!
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// [`read()`]: trait.Read.html#tymethod.read
|
||
|
|
/// [`std::io`]: ../../std/io/index.html
|
||
|
|
/// [`File`]: ../fs/struct.File.html
|
||
|
|
/// [`BufRead`]: trait.BufRead.html
|
||
|
|
/// [`BufReader`]: struct.BufReader.html
|
||
|
|
/// [`&str`]: ../../std/primitive.str.html
|
||
|
|
/// [slice]: ../../std/primitive.slice.html
|
||
|
|
pub trait Read {
|
||
|
|
/// Pull some bytes from this source into the specified buffer, returning
|
||
|
|
/// how many bytes were read.
|
||
|
|
///
|
||
|
|
/// This function does not provide any guarantees about whether it blocks
|
||
|
|
/// waiting for data, but if an object needs to block for a read and cannot,
|
||
|
|
/// it will typically signal this via an [`Err`] return value.
|
||
|
|
///
|
||
|
|
/// If the return value of this method is [`Ok(n)`], then it must be
|
||
|
|
/// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
|
||
|
|
/// that the buffer `buf` has been filled in with `n` bytes of data from this
|
||
|
|
/// source. If `n` is `0`, then it can indicate one of two scenarios:
|
||
|
|
///
|
||
|
|
/// 1. This reader has reached its "end of file" and will likely no longer
|
||
|
|
/// be able to produce bytes. Note that this does not mean that the
|
||
|
|
/// reader will *always* no longer be able to produce bytes.
|
||
|
|
/// 2. The buffer specified was 0 bytes in length.
|
||
|
|
///
|
||
|
|
/// No guarantees are provided about the contents of `buf` when this
|
||
|
|
/// function is called, implementations cannot rely on any property of the
|
||
|
|
/// contents of `buf` being true. It is recommended that *implementations*
|
||
|
|
/// only write data to `buf` instead of reading its contents.
|
||
|
|
///
|
||
|
|
/// Correspondingly, however, *callers* of this method may not assume any guarantees
|
||
|
|
/// about how the implementation uses `buf`. The trait is safe to implement,
|
||
|
|
/// so it is possible that the code that's supposed to write to the buffer might also read
|
||
|
|
/// from it. It is your responsibility to make sure that `buf` is initialized
|
||
|
|
/// before calling `read`. Calling `read` with an uninitialized `buf` (of the kind one
|
||
|
|
/// obtains via [`MaybeUninit<T>`]) is not safe, and can lead to undefined behavior.
|
||
|
|
///
|
||
|
|
/// [`MaybeUninit<T>`]: ../mem/union.MaybeUninit.html
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// If this function encounters any form of I/O or other error, an error
|
||
|
|
/// variant will be returned. If an error is returned then it must be
|
||
|
|
/// guaranteed that no bytes were read.
|
||
|
|
///
|
||
|
|
/// An error of the [`ErrorKind::Interrupted`] kind is non-fatal and the read
|
||
|
|
/// operation should be retried if there is nothing else to do.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [`Err`]: ../../std/result/enum.Result.html#variant.Err
|
||
|
|
/// [`Ok(n)`]: ../../std/result/enum.Result.html#variant.Ok
|
||
|
|
/// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
|
||
|
|
/// [`File`]: ../fs/struct.File.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = [0; 10];
|
||
|
|
///
|
||
|
|
/// // read up to 10 bytes
|
||
|
|
/// let n = f.read(&mut buffer[..])?;
|
||
|
|
///
|
||
|
|
/// println!("The bytes: {:?}", &buffer[..n]);
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
|
||
|
|
|
||
|
|
/// Determines if this `Read`er can work with buffers of uninitialized
|
||
|
|
/// memory.
|
||
|
|
///
|
||
|
|
/// The default implementation returns an initializer which will zero
|
||
|
|
/// buffers.
|
||
|
|
///
|
||
|
|
/// If a `Read`er guarantees that it can work properly with uninitialized
|
||
|
|
/// memory, it should call [`Initializer::nop()`]. See the documentation for
|
||
|
|
/// [`Initializer`] for details.
|
||
|
|
///
|
||
|
|
/// The behavior of this method must be independent of the state of the
|
||
|
|
/// `Read`er - the method only takes `&self` so that it can be used through
|
||
|
|
/// trait objects.
|
||
|
|
///
|
||
|
|
/// # Safety
|
||
|
|
///
|
||
|
|
/// This method is unsafe because a `Read`er could otherwise return a
|
||
|
|
/// non-zeroing `Initializer` from another `Read` type without an `unsafe`
|
||
|
|
/// block.
|
||
|
|
///
|
||
|
|
/// [`Initializer::nop()`]: ../../std/io/struct.Initializer.html#method.nop
|
||
|
|
/// [`Initializer`]: ../../std/io/struct.Initializer.html
|
||
|
|
#[inline]
|
||
|
|
unsafe fn initializer(&self) -> Initializer {
|
||
|
|
Initializer::zeroing()
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Read all bytes until EOF in this source, placing them into `buf`.
|
||
|
|
///
|
||
|
|
/// All bytes read from this source will be appended to the specified buffer
|
||
|
|
/// `buf`. This function will continuously call [`read()`] to append more data to
|
||
|
|
/// `buf` until [`read()`] returns either [`Ok(0)`] or an error of
|
||
|
|
/// non-[`ErrorKind::Interrupted`] kind.
|
||
|
|
///
|
||
|
|
/// If successful, this function will return the total number of bytes read.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// If this function encounters an error of the kind
|
||
|
|
/// [`ErrorKind::Interrupted`] then the error is ignored and the operation
|
||
|
|
/// will continue.
|
||
|
|
///
|
||
|
|
/// If any other read error is encountered then this function immediately
|
||
|
|
/// returns. Any bytes which have already been read will be appended to
|
||
|
|
/// `buf`.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [`read()`]: trait.Read.html#tymethod.read
|
||
|
|
/// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok
|
||
|
|
/// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
|
||
|
|
/// [`File`]: ../fs/struct.File.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = Vec::new();
|
||
|
|
///
|
||
|
|
/// // read the whole file
|
||
|
|
/// f.read_to_end(&mut buffer)?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// (See also the [`std::fs::read`] convenience function for reading from a
|
||
|
|
/// file.)
|
||
|
|
///
|
||
|
|
/// [`std::fs::read`]: ../fs/fn.read.html
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
|
||
|
|
read_to_end(self, buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Read all bytes until EOF in this source, appending them to `buf`.
|
||
|
|
///
|
||
|
|
/// If successful, this function returns the number of bytes which were read
|
||
|
|
/// and appended to `buf`.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// If the data in this stream is *not* valid UTF-8 then an error is
|
||
|
|
/// returned and `buf` is unchanged.
|
||
|
|
///
|
||
|
|
/// See [`read_to_end`][readtoend] for other error semantics.
|
||
|
|
///
|
||
|
|
/// [readtoend]: #method.read_to_end
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`][file]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [file]: ../fs/struct.File.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = String::new();
|
||
|
|
///
|
||
|
|
/// f.read_to_string(&mut buffer)?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// (See also the [`std::fs::read_to_string`] convenience function for
|
||
|
|
/// reading from a file.)
|
||
|
|
///
|
||
|
|
/// [`std::fs::read_to_string`]: ../fs/fn.read_to_string.html
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
|
||
|
|
// Note that we do *not* call `.read_to_end()` here. We are passing
|
||
|
|
// `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
|
||
|
|
// method to fill it up. An arbitrary implementation could overwrite the
|
||
|
|
// entire contents of the vector, not just append to it (which is what
|
||
|
|
// we are expecting).
|
||
|
|
//
|
||
|
|
// To prevent extraneously checking the UTF-8-ness of the entire buffer
|
||
|
|
// we pass it to our hardcoded `read_to_end` implementation which we
|
||
|
|
// know is guaranteed to only read data into the end of the buffer.
|
||
|
|
append_to_string(buf, |b| read_to_end(self, b))
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Read the exact number of bytes required to fill `buf`.
|
||
|
|
///
|
||
|
|
/// This function reads as many bytes as necessary to completely fill the
|
||
|
|
/// specified buffer `buf`.
|
||
|
|
///
|
||
|
|
/// No guarantees are provided about the contents of `buf` when this
|
||
|
|
/// function is called, implementations cannot rely on any property of the
|
||
|
|
/// contents of `buf` being true. It is recommended that implementations
|
||
|
|
/// only write data to `buf` instead of reading its contents.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// If this function encounters an error of the kind
|
||
|
|
/// [`ErrorKind::Interrupted`] then the error is ignored and the operation
|
||
|
|
/// will continue.
|
||
|
|
///
|
||
|
|
/// If this function encounters an "end of file" before completely filling
|
||
|
|
/// the buffer, it returns an error of the kind [`ErrorKind::UnexpectedEof`].
|
||
|
|
/// The contents of `buf` are unspecified in this case.
|
||
|
|
///
|
||
|
|
/// If any other read error is encountered then this function immediately
|
||
|
|
/// returns. The contents of `buf` are unspecified in this case.
|
||
|
|
///
|
||
|
|
/// If this function returns an error, it is unspecified how many bytes it
|
||
|
|
/// has read, but it will never read more than would be necessary to
|
||
|
|
/// completely fill the buffer.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [`File`]: ../fs/struct.File.html
|
||
|
|
/// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
|
||
|
|
/// [`ErrorKind::UnexpectedEof`]: ../../std/io/enum.ErrorKind.html#variant.UnexpectedEof
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = [0; 10];
|
||
|
|
///
|
||
|
|
/// // read exactly 10 bytes
|
||
|
|
/// f.read_exact(&mut buffer)?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
|
||
|
|
while !buf.is_empty() {
|
||
|
|
match self.read(buf) {
|
||
|
|
Ok(0) => break,
|
||
|
|
Ok(n) => {
|
||
|
|
let tmp = buf;
|
||
|
|
buf = &mut tmp[n..];
|
||
|
|
}
|
||
|
|
Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
|
||
|
|
Err(e) => return Err(e),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if !buf.is_empty() {
|
||
|
|
Err(Error::new(ErrorKind::UnexpectedEof, "failed to fill whole buffer"))
|
||
|
|
} else {
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Creates a "by reference" adaptor for this instance of `Read`.
|
||
|
|
///
|
||
|
|
/// The returned adaptor also implements `Read` and will simply borrow this
|
||
|
|
/// current reader.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`][file]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [file]: ../fs/struct.File.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::Read;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = Vec::new();
|
||
|
|
/// let mut other_buffer = Vec::new();
|
||
|
|
///
|
||
|
|
/// {
|
||
|
|
/// let reference = f.by_ref();
|
||
|
|
///
|
||
|
|
/// // read at most 5 bytes
|
||
|
|
/// reference.take(5).read_to_end(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// } // drop our &mut reference so we can use f again
|
||
|
|
///
|
||
|
|
/// // original file still usable, read the rest
|
||
|
|
/// f.read_to_end(&mut other_buffer)?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn by_ref(&mut self) -> &mut Self
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
self
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Transforms this `Read` instance to an [`Iterator`] over its bytes.
|
||
|
|
///
|
||
|
|
/// The returned type implements [`Iterator`] where the `Item` is
|
||
|
|
/// [`Result`]`<`[`u8`]`, `[`io::Error`]`>`.
|
||
|
|
/// The yielded item is [`Ok`] if a byte was successfully read and [`Err`]
|
||
|
|
/// otherwise. EOF is mapped to returning [`None`] from this iterator.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`][file]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [file]: ../fs/struct.File.html
|
||
|
|
/// [`Iterator`]: ../../std/iter/trait.Iterator.html
|
||
|
|
/// [`Result`]: ../../std/result/enum.Result.html
|
||
|
|
/// [`io::Error`]: ../../std/io/struct.Error.html
|
||
|
|
/// [`u8`]: ../../std/primitive.u8.html
|
||
|
|
/// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok
|
||
|
|
/// [`Err`]: ../../std/result/enum.Result.html#variant.Err
|
||
|
|
/// [`None`]: ../../std/option/enum.Option.html#variant.None
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// for byte in f.bytes() {
|
||
|
|
/// println!("{}", byte.unwrap());
|
||
|
|
/// }
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn bytes(self) -> Bytes<Self>
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
Bytes { inner: self }
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Creates an adaptor which will chain this stream with another.
|
||
|
|
///
|
||
|
|
/// The returned `Read` instance will first read all bytes from this object
|
||
|
|
/// until EOF is encountered. Afterwards the output is equivalent to the
|
||
|
|
/// output of `next`.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`][file]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [file]: ../fs/struct.File.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f1 = File::open("foo.txt")?;
|
||
|
|
/// let mut f2 = File::open("bar.txt")?;
|
||
|
|
///
|
||
|
|
/// let mut handle = f1.chain(f2);
|
||
|
|
/// let mut buffer = String::new();
|
||
|
|
///
|
||
|
|
/// // read the value into a String. We could use any Read method here,
|
||
|
|
/// // this is just one example.
|
||
|
|
/// handle.read_to_string(&mut buffer)?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn chain<R: Read>(self, next: R) -> Chain<Self, R>
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
Chain { first: self, second: next, done_first: false }
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Creates an adaptor which will read at most `limit` bytes from it.
|
||
|
|
///
|
||
|
|
/// This function returns a new instance of `Read` which will read at most
|
||
|
|
/// `limit` bytes, after which it will always return EOF ([`Ok(0)`]). Any
|
||
|
|
/// read errors will not count towards the number of bytes read and future
|
||
|
|
/// calls to [`read()`] may succeed.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`]s implement `Read`:
|
||
|
|
///
|
||
|
|
/// [`File`]: ../fs/struct.File.html
|
||
|
|
/// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok
|
||
|
|
/// [`read()`]: trait.Read.html#tymethod.read
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
/// let mut buffer = [0; 5];
|
||
|
|
///
|
||
|
|
/// // read at most five bytes
|
||
|
|
/// let mut handle = f.take(5);
|
||
|
|
///
|
||
|
|
/// handle.read(&mut buffer)?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn take(self, limit: u64) -> Take<Self>
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
Take { inner: self, limit }
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// A type used to conditionally initialize buffers passed to `Read` methods.
|
||
|
|
#[derive(Debug)]
|
||
|
|
pub struct Initializer(bool);
|
||
|
|
|
||
|
|
impl Initializer {
|
||
|
|
/// Returns a new `Initializer` which will zero out buffers.
|
||
|
|
#[inline]
|
||
|
|
pub fn zeroing() -> Initializer {
|
||
|
|
Initializer(true)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Returns a new `Initializer` which will not zero out buffers.
|
||
|
|
///
|
||
|
|
/// # Safety
|
||
|
|
///
|
||
|
|
/// This may only be called by `Read`ers which guarantee that they will not
|
||
|
|
/// read from buffers passed to `Read` methods, and that the return value of
|
||
|
|
/// the method accurately reflects the number of bytes that have been
|
||
|
|
/// written to the head of the buffer.
|
||
|
|
#[inline]
|
||
|
|
pub unsafe fn nop() -> Initializer {
|
||
|
|
Initializer(false)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Indicates if a buffer should be initialized.
|
||
|
|
#[inline]
|
||
|
|
pub fn should_initialize(&self) -> bool {
|
||
|
|
self.0
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Initializes a buffer if necessary.
|
||
|
|
#[inline]
|
||
|
|
pub fn initialize(&self, buf: &mut [u8]) {
|
||
|
|
if self.should_initialize() {
|
||
|
|
unsafe { ptr::write_bytes(buf.as_mut_ptr(), 0, buf.len()) }
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// A trait for objects which are byte-oriented sinks.
|
||
|
|
///
|
||
|
|
/// Implementors of the `Write` trait are sometimes called 'writers'.
|
||
|
|
///
|
||
|
|
/// Writers are defined by two required methods, [`write`] and [`flush`]:
|
||
|
|
///
|
||
|
|
/// * The [`write`] method will attempt to write some data into the object,
|
||
|
|
/// returning how many bytes were successfully written.
|
||
|
|
///
|
||
|
|
/// * The [`flush`] method is useful for adaptors and explicit buffers
|
||
|
|
/// themselves for ensuring that all buffered data has been pushed out to the
|
||
|
|
/// 'true sink'.
|
||
|
|
///
|
||
|
|
/// Writers are intended to be composable with one another. Many implementors
|
||
|
|
/// throughout [`std::io`] take and provide types which implement the `Write`
|
||
|
|
/// trait.
|
||
|
|
///
|
||
|
|
/// [`write`]: #tymethod.write
|
||
|
|
/// [`flush`]: #tymethod.flush
|
||
|
|
/// [`std::io`]: index.html
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> std::io::Result<()> {
|
||
|
|
/// let data = b"some bytes";
|
||
|
|
///
|
||
|
|
/// let mut pos = 0;
|
||
|
|
/// let mut buffer = File::create("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// while pos < data.len() {
|
||
|
|
/// let bytes_written = buffer.write(&data[pos..])?;
|
||
|
|
/// pos += bytes_written;
|
||
|
|
/// }
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// The trait also provides convenience methods like [`write_all`], which calls
|
||
|
|
/// `write` in a loop until its entire input has been written.
|
||
|
|
///
|
||
|
|
/// [`write_all`]: #method.write_all
|
||
|
|
pub trait Write {
|
||
|
|
/// Write a buffer into this writer, returning how many bytes were written.
|
||
|
|
///
|
||
|
|
/// This function will attempt to write the entire contents of `buf`, but
|
||
|
|
/// the entire write may not succeed, or the write may also generate an
|
||
|
|
/// error. A call to `write` represents *at most one* attempt to write to
|
||
|
|
/// any wrapped object.
|
||
|
|
///
|
||
|
|
/// Calls to `write` are not guaranteed to block waiting for data to be
|
||
|
|
/// written, and a write which would otherwise block can be indicated through
|
||
|
|
/// an [`Err`] variant.
|
||
|
|
///
|
||
|
|
/// If the return value is [`Ok(n)`] then it must be guaranteed that
|
||
|
|
/// `n <= buf.len()`. A return value of `0` typically means that the
|
||
|
|
/// underlying object is no longer able to accept bytes and will likely not
|
||
|
|
/// be able to in the future as well, or that the buffer provided is empty.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// Each call to `write` may generate an I/O error indicating that the
|
||
|
|
/// operation could not be completed. If an error is returned then no bytes
|
||
|
|
/// in the buffer were written to this writer.
|
||
|
|
///
|
||
|
|
/// It is **not** considered an error if the entire buffer could not be
|
||
|
|
/// written to this writer.
|
||
|
|
///
|
||
|
|
/// An error of the [`ErrorKind::Interrupted`] kind is non-fatal and the
|
||
|
|
/// write operation should be retried if there is nothing else to do.
|
||
|
|
///
|
||
|
|
/// [`Err`]: ../../std/result/enum.Result.html#variant.Err
|
||
|
|
/// [`Ok(n)`]: ../../std/result/enum.Result.html#variant.Ok
|
||
|
|
/// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> std::io::Result<()> {
|
||
|
|
/// let mut buffer = File::create("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// // Writes some prefix of the byte string, not necessarily all of it.
|
||
|
|
/// buffer.write(b"some bytes")?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn write(&mut self, buf: &[u8]) -> Result<usize>;
|
||
|
|
|
||
|
|
/// Flush this output stream, ensuring that all intermediately buffered
|
||
|
|
/// contents reach their destination.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// It is considered an error if not all bytes could be written due to
|
||
|
|
/// I/O errors or EOF being reached.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::io::BufWriter;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> std::io::Result<()> {
|
||
|
|
/// let mut buffer = BufWriter::new(File::create("foo.txt")?);
|
||
|
|
///
|
||
|
|
/// buffer.write_all(b"some bytes")?;
|
||
|
|
/// buffer.flush()?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn flush(&mut self) -> Result<()>;
|
||
|
|
|
||
|
|
/// Attempts to write an entire buffer into this writer.
|
||
|
|
///
|
||
|
|
/// This method will continuously call [`write`] until there is no more data
|
||
|
|
/// to be written or an error of non-[`ErrorKind::Interrupted`] kind is
|
||
|
|
/// returned. This method will not return until the entire buffer has been
|
||
|
|
/// successfully written or such an error occurs. The first error that is
|
||
|
|
/// not of [`ErrorKind::Interrupted`] kind generated from this method will be
|
||
|
|
/// returned.
|
||
|
|
///
|
||
|
|
/// If the buffer contains no data, this will never call [`write`].
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// This function will return the first error of
|
||
|
|
/// non-[`ErrorKind::Interrupted`] kind that [`write`] returns.
|
||
|
|
///
|
||
|
|
/// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
|
||
|
|
/// [`write`]: #tymethod.write
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> std::io::Result<()> {
|
||
|
|
/// let mut buffer = File::create("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// buffer.write_all(b"some bytes")?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
|
||
|
|
while !buf.is_empty() {
|
||
|
|
match self.write(buf) {
|
||
|
|
Ok(0) => {
|
||
|
|
return Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"));
|
||
|
|
}
|
||
|
|
Ok(n) => buf = &buf[n..],
|
||
|
|
Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
|
||
|
|
Err(e) => return Err(e),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Attempts to write multiple buffers into this writer.
|
||
|
|
///
|
||
|
|
/// This method will continuously call [`write_vectored`] until there is no
|
||
|
|
/// more data to be written or an error of non-[`ErrorKind::Interrupted`]
|
||
|
|
/// kind is returned. This method will not return until all buffers have
|
||
|
|
/// been successfully written or such an error occurs. The first error that
|
||
|
|
/// is not of [`ErrorKind::Interrupted`] kind generated from this method
|
||
|
|
/// will be returned.
|
||
|
|
///
|
||
|
|
/// If the buffer contains no data, this will never call [`write_vectored`].
|
||
|
|
///
|
||
|
|
/// [`write_vectored`]: #method.write_vectored
|
||
|
|
/// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
|
||
|
|
///
|
||
|
|
/// # Notes
|
||
|
|
///
|
||
|
|
///
|
||
|
|
/// Unlike `io::Write::write_vectored`, this takes a *mutable* reference to
|
||
|
|
/// a slice of `IoSlice`s, not an immutable one. That's because we need to
|
||
|
|
/// modify the slice to keep track of the bytes already written.
|
||
|
|
///
|
||
|
|
/// Once this function returns, the contents of `bufs` are unspecified, as
|
||
|
|
/// this depends on how many calls to `write_vectored` were necessary. It is
|
||
|
|
/// best to understand this function as taking ownership of `bufs` and to
|
||
|
|
/// not use `bufs` afterwards. The underlying buffers, to which the
|
||
|
|
/// `IoSlice`s point (but not the `IoSlice`s themselves), are unchanged and
|
||
|
|
/// can be reused.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```
|
||
|
|
/// #![feature(write_all_vectored)]
|
||
|
|
/// # fn main() -> std::io::Result<()> {
|
||
|
|
///
|
||
|
|
/// use std::io::{Write, IoSlice};
|
||
|
|
///
|
||
|
|
/// let mut writer = Vec::new();
|
||
|
|
/// let bufs = &mut [
|
||
|
|
/// IoSlice::new(&[1]),
|
||
|
|
/// IoSlice::new(&[2, 3]),
|
||
|
|
/// IoSlice::new(&[4, 5, 6]),
|
||
|
|
/// ];
|
||
|
|
///
|
||
|
|
/// writer.write_all_vectored(bufs)?;
|
||
|
|
/// // Note: the contents of `bufs` is now undefined, see the Notes section.
|
||
|
|
///
|
||
|
|
/// assert_eq!(writer, &[1, 2, 3, 4, 5, 6]);
|
||
|
|
/// # Ok(()) }
|
||
|
|
/// ```
|
||
|
|
/*fn write_all_vectored(&mut self, mut bufs: &mut [IoSlice<'_>]) -> Result<()> {
|
||
|
|
while !bufs.is_empty() {
|
||
|
|
match self.write_vectored(bufs) {
|
||
|
|
Ok(0) => {
|
||
|
|
return Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"));
|
||
|
|
}
|
||
|
|
Ok(n) => bufs = IoSlice::advance(mem::take(&mut bufs), n),
|
||
|
|
Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
|
||
|
|
Err(e) => return Err(e),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
Ok(())
|
||
|
|
}*/
|
||
|
|
|
||
|
|
/// Writes a formatted string into this writer, returning any error
|
||
|
|
/// encountered.
|
||
|
|
///
|
||
|
|
/// This method is primarily used to interface with the
|
||
|
|
/// [`format_args!`][formatargs] macro, but it is rare that this should
|
||
|
|
/// explicitly be called. The [`write!`][write] macro should be favored to
|
||
|
|
/// invoke this method instead.
|
||
|
|
///
|
||
|
|
/// [formatargs]: ../macro.format_args.html
|
||
|
|
/// [write]: ../macro.write.html
|
||
|
|
///
|
||
|
|
/// This function internally uses the [`write_all`][writeall] method on
|
||
|
|
/// this trait and hence will continuously write data so long as no errors
|
||
|
|
/// are received. This also means that partial writes are not indicated in
|
||
|
|
/// this signature.
|
||
|
|
///
|
||
|
|
/// [writeall]: #method.write_all
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// This function will return any I/O error reported while formatting.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> std::io::Result<()> {
|
||
|
|
/// let mut buffer = File::create("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// // this call
|
||
|
|
/// write!(buffer, "{:.*}", 2, 1.234567)?;
|
||
|
|
/// // turns into this:
|
||
|
|
/// buffer.write_fmt(format_args!("{:.*}", 2, 1.234567))?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> Result<()> {
|
||
|
|
// Create a shim which translates a Write to a fmt::Write and saves
|
||
|
|
// off I/O errors. instead of discarding them
|
||
|
|
struct Adaptor<'a, T: ?Sized + 'a> {
|
||
|
|
inner: &'a mut T,
|
||
|
|
error: Result<()>,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T: Write + ?Sized> fmt::Write for Adaptor<'_, T> {
|
||
|
|
fn write_str(&mut self, s: &str) -> fmt::Result {
|
||
|
|
match self.inner.write_all(s.as_bytes()) {
|
||
|
|
Ok(()) => Ok(()),
|
||
|
|
Err(e) => {
|
||
|
|
self.error = Err(e);
|
||
|
|
Err(fmt::Error)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
let mut output = Adaptor { inner: self, error: Ok(()) };
|
||
|
|
match fmt::write(&mut output, fmt) {
|
||
|
|
Ok(()) => Ok(()),
|
||
|
|
Err(..) => {
|
||
|
|
// check if the error came from the underlying `Write` or not
|
||
|
|
if output.error.is_err() {
|
||
|
|
output.error
|
||
|
|
} else {
|
||
|
|
Err(Error::new(ErrorKind::Other, "formatter error"))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Creates a "by reference" adaptor for this instance of `Write`.
|
||
|
|
///
|
||
|
|
/// The returned adaptor also implements `Write` and will simply borrow this
|
||
|
|
/// current writer.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::Write;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> std::io::Result<()> {
|
||
|
|
/// let mut buffer = File::create("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// let reference = buffer.by_ref();
|
||
|
|
///
|
||
|
|
/// // we can use reference just like our original buffer
|
||
|
|
/// reference.write_all(b"some bytes")?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn by_ref(&mut self) -> &mut Self
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
self
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// The `Seek` trait provides a cursor which can be moved within a stream of
|
||
|
|
/// bytes.
|
||
|
|
///
|
||
|
|
/// The stream typically has a fixed size, allowing seeking relative to either
|
||
|
|
/// end or the current offset.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`File`][file]s implement `Seek`:
|
||
|
|
///
|
||
|
|
/// [file]: ../fs/struct.File.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
/// use std::io::SeekFrom;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// // move the cursor 42 bytes from the start of the file
|
||
|
|
/// f.seek(SeekFrom::Start(42))?;
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub trait Seek {
|
||
|
|
/// Seek to an offset, in bytes, in a stream.
|
||
|
|
///
|
||
|
|
/// A seek beyond the end of a stream is allowed, but behavior is defined
|
||
|
|
/// by the implementation.
|
||
|
|
///
|
||
|
|
/// If the seek operation completed successfully,
|
||
|
|
/// this method returns the new position from the start of the stream.
|
||
|
|
/// That position can be used later with [`SeekFrom::Start`].
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// Seeking to a negative offset is considered an error.
|
||
|
|
///
|
||
|
|
/// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
|
||
|
|
fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
|
||
|
|
|
||
|
|
/// Returns the length of this stream (in bytes).
|
||
|
|
///
|
||
|
|
/// This method is implemented using up to three seek operations. If this
|
||
|
|
/// method returns successfully, the seek position is unchanged (i.e. the
|
||
|
|
/// position before calling this method is the same as afterwards).
|
||
|
|
/// However, if this method returns an error, the seek position is
|
||
|
|
/// unspecified.
|
||
|
|
///
|
||
|
|
/// If you need to obtain the length of *many* streams and you don't care
|
||
|
|
/// about the seek position afterwards, you can reduce the number of seek
|
||
|
|
/// operations by simply calling `seek(SeekFrom::End(0))` and using its
|
||
|
|
/// return value (it is also the stream length).
|
||
|
|
///
|
||
|
|
/// Note that length of a stream can change over time (for example, when
|
||
|
|
/// data is appended to a file). So calling this method multiple times does
|
||
|
|
/// not necessarily return the same length each time.
|
||
|
|
///
|
||
|
|
///
|
||
|
|
/// # Example
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// #![feature(seek_convenience)]
|
||
|
|
/// use std::{
|
||
|
|
/// io::{self, Seek},
|
||
|
|
/// fs::File,
|
||
|
|
/// };
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// let len = f.stream_len()?;
|
||
|
|
/// println!("The file is currently {} bytes long", len);
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn stream_len(&mut self) -> Result<u64> {
|
||
|
|
let old_pos = self.stream_position()?;
|
||
|
|
let len = self.seek(SeekFrom::End(0))?;
|
||
|
|
|
||
|
|
// Avoid seeking a third time when we were already at the end of the
|
||
|
|
// stream. The branch is usually way cheaper than a seek operation.
|
||
|
|
if old_pos != len {
|
||
|
|
self.seek(SeekFrom::Start(old_pos))?;
|
||
|
|
}
|
||
|
|
|
||
|
|
Ok(len)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Returns the current seek position from the start of the stream.
|
||
|
|
///
|
||
|
|
/// This is equivalent to `self.seek(SeekFrom::Current(0))`.
|
||
|
|
///
|
||
|
|
///
|
||
|
|
/// # Example
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// #![feature(seek_convenience)]
|
||
|
|
/// use std::{
|
||
|
|
/// io::{self, BufRead, BufReader, Seek},
|
||
|
|
/// fs::File,
|
||
|
|
/// };
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut f = BufReader::new(File::open("foo.txt")?);
|
||
|
|
///
|
||
|
|
/// let before = f.stream_position()?;
|
||
|
|
/// f.read_line(&mut String::new())?;
|
||
|
|
/// let after = f.stream_position()?;
|
||
|
|
///
|
||
|
|
/// println!("The first line was {} bytes long", after - before);
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
fn stream_position(&mut self) -> Result<u64> {
|
||
|
|
self.seek(SeekFrom::Current(0))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Enumeration of possible methods to seek within an I/O object.
|
||
|
|
///
|
||
|
|
/// It is used by the [`Seek`] trait.
|
||
|
|
///
|
||
|
|
/// [`Seek`]: trait.Seek.html
|
||
|
|
#[derive(Copy, PartialEq, Eq, Clone, Debug)]
|
||
|
|
pub enum SeekFrom {
|
||
|
|
/// Sets the offset to the provided number of bytes.
|
||
|
|
Start(u64),
|
||
|
|
/// Sets the offset to the size of this object plus the specified number of
|
||
|
|
/// bytes.
|
||
|
|
///
|
||
|
|
/// It is possible to seek beyond the end of an object, but it's an error to
|
||
|
|
/// seek before byte 0.
|
||
|
|
End(i64),
|
||
|
|
/// Sets the offset to the current position plus the specified number of
|
||
|
|
/// bytes.
|
||
|
|
///
|
||
|
|
/// It is possible to seek beyond the end of an object, but it's an error to
|
||
|
|
/// seek before byte 0.
|
||
|
|
Current(i64),
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>) -> Result<usize> {
|
||
|
|
let mut read = 0;
|
||
|
|
loop {
|
||
|
|
let (done, used) = {
|
||
|
|
let available = match r.fill_buf() {
|
||
|
|
Ok(n) => n,
|
||
|
|
Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
|
||
|
|
Err(e) => return Err(e),
|
||
|
|
};
|
||
|
|
match memchr::memchr(delim, available) {
|
||
|
|
Some(i) => {
|
||
|
|
buf.extend_from_slice(&available[..=i]);
|
||
|
|
(true, i + 1)
|
||
|
|
}
|
||
|
|
None => {
|
||
|
|
buf.extend_from_slice(available);
|
||
|
|
(false, available.len())
|
||
|
|
}
|
||
|
|
}
|
||
|
|
};
|
||
|
|
r.consume(used);
|
||
|
|
read += used;
|
||
|
|
if done || used == 0 {
|
||
|
|
return Ok(read);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
|
||
|
|
/// to perform extra ways of reading.
|
||
|
|
///
|
||
|
|
/// For example, reading line-by-line is inefficient without using a buffer, so
|
||
|
|
/// if you want to read by line, you'll need `BufRead`, which includes a
|
||
|
|
/// [`read_line`] method as well as a [`lines`] iterator.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// A locked standard input implements `BufRead`:
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
///
|
||
|
|
/// let stdin = io::stdin();
|
||
|
|
/// for line in stdin.lock().lines() {
|
||
|
|
/// println!("{}", line.unwrap());
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// If you have something that implements [`Read`], you can use the [`BufReader`
|
||
|
|
/// type][`BufReader`] to turn it into a `BufRead`.
|
||
|
|
///
|
||
|
|
/// For example, [`File`] implements [`Read`], but not `BufRead`.
|
||
|
|
/// [`BufReader`] to the rescue!
|
||
|
|
///
|
||
|
|
/// [`BufReader`]: struct.BufReader.html
|
||
|
|
/// [`File`]: ../fs/struct.File.html
|
||
|
|
/// [`read_line`]: #method.read_line
|
||
|
|
/// [`lines`]: #method.lines
|
||
|
|
/// [`Read`]: trait.Read.html
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io::{self, BufReader};
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let f = File::open("foo.txt")?;
|
||
|
|
/// let f = BufReader::new(f);
|
||
|
|
///
|
||
|
|
/// for line in f.lines() {
|
||
|
|
/// println!("{}", line.unwrap());
|
||
|
|
/// }
|
||
|
|
///
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
pub trait BufRead: Read {
|
||
|
|
/// Returns the contents of the internal buffer, filling it with more data
|
||
|
|
/// from the inner reader if it is empty.
|
||
|
|
///
|
||
|
|
/// This function is a lower-level call. It needs to be paired with the
|
||
|
|
/// [`consume`] method to function properly. When calling this
|
||
|
|
/// method, none of the contents will be "read" in the sense that later
|
||
|
|
/// calling `read` may return the same contents. As such, [`consume`] must
|
||
|
|
/// be called with the number of bytes that are consumed from this buffer to
|
||
|
|
/// ensure that the bytes are never returned twice.
|
||
|
|
///
|
||
|
|
/// [`consume`]: #tymethod.consume
|
||
|
|
///
|
||
|
|
/// An empty buffer returned indicates that the stream has reached EOF.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// This function will return an I/O error if the underlying reader was
|
||
|
|
/// read, but returned an error.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// A locked standard input implements `BufRead`:
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
///
|
||
|
|
/// let stdin = io::stdin();
|
||
|
|
/// let mut stdin = stdin.lock();
|
||
|
|
///
|
||
|
|
/// let buffer = stdin.fill_buf().unwrap();
|
||
|
|
///
|
||
|
|
/// // work with buffer
|
||
|
|
/// println!("{:?}", buffer);
|
||
|
|
///
|
||
|
|
/// // ensure the bytes we worked with aren't returned again later
|
||
|
|
/// let length = buffer.len();
|
||
|
|
/// stdin.consume(length);
|
||
|
|
/// ```
|
||
|
|
fn fill_buf(&mut self) -> Result<&[u8]>;
|
||
|
|
|
||
|
|
/// Tells this buffer that `amt` bytes have been consumed from the buffer,
|
||
|
|
/// so they should no longer be returned in calls to `read`.
|
||
|
|
///
|
||
|
|
/// This function is a lower-level call. It needs to be paired with the
|
||
|
|
/// [`fill_buf`] method to function properly. This function does
|
||
|
|
/// not perform any I/O, it simply informs this object that some amount of
|
||
|
|
/// its buffer, returned from [`fill_buf`], has been consumed and should
|
||
|
|
/// no longer be returned. As such, this function may do odd things if
|
||
|
|
/// [`fill_buf`] isn't called before calling it.
|
||
|
|
///
|
||
|
|
/// The `amt` must be `<=` the number of bytes in the buffer returned by
|
||
|
|
/// [`fill_buf`].
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// Since `consume()` is meant to be used with [`fill_buf`],
|
||
|
|
/// that method's example includes an example of `consume()`.
|
||
|
|
///
|
||
|
|
/// [`fill_buf`]: #tymethod.fill_buf
|
||
|
|
fn consume(&mut self, amt: usize);
|
||
|
|
|
||
|
|
/// Read all bytes into `buf` until the delimiter `byte` or EOF is reached.
|
||
|
|
///
|
||
|
|
/// This function will read bytes from the underlying stream until the
|
||
|
|
/// delimiter or EOF is found. Once found, all bytes up to, and including,
|
||
|
|
/// the delimiter (if found) will be appended to `buf`.
|
||
|
|
///
|
||
|
|
/// If successful, this function will return the total number of bytes read.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// This function will ignore all instances of [`ErrorKind::Interrupted`] and
|
||
|
|
/// will otherwise return any errors returned by [`fill_buf`].
|
||
|
|
///
|
||
|
|
/// If an I/O error is encountered then all bytes read so far will be
|
||
|
|
/// present in `buf` and its length will have been adjusted appropriately.
|
||
|
|
///
|
||
|
|
/// [`fill_buf`]: #tymethod.fill_buf
|
||
|
|
/// [`ErrorKind::Interrupted`]: enum.ErrorKind.html#variant.Interrupted
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
|
||
|
|
/// this example, we use [`Cursor`] to read all the bytes in a byte slice
|
||
|
|
/// in hyphen delimited segments:
|
||
|
|
///
|
||
|
|
/// [`Cursor`]: struct.Cursor.html
|
||
|
|
///
|
||
|
|
/// ```
|
||
|
|
/// use std::io::{self, BufRead};
|
||
|
|
///
|
||
|
|
/// let mut cursor = io::Cursor::new(b"lorem-ipsum");
|
||
|
|
/// let mut buf = vec![];
|
||
|
|
///
|
||
|
|
/// // cursor is at 'l'
|
||
|
|
/// let num_bytes = cursor.read_until(b'-', &mut buf)
|
||
|
|
/// .expect("reading from cursor won't fail");
|
||
|
|
/// assert_eq!(num_bytes, 6);
|
||
|
|
/// assert_eq!(buf, b"lorem-");
|
||
|
|
/// buf.clear();
|
||
|
|
///
|
||
|
|
/// // cursor is at 'i'
|
||
|
|
/// let num_bytes = cursor.read_until(b'-', &mut buf)
|
||
|
|
/// .expect("reading from cursor won't fail");
|
||
|
|
/// assert_eq!(num_bytes, 5);
|
||
|
|
/// assert_eq!(buf, b"ipsum");
|
||
|
|
/// buf.clear();
|
||
|
|
///
|
||
|
|
/// // cursor is at EOF
|
||
|
|
/// let num_bytes = cursor.read_until(b'-', &mut buf)
|
||
|
|
/// .expect("reading from cursor won't fail");
|
||
|
|
/// assert_eq!(num_bytes, 0);
|
||
|
|
/// assert_eq!(buf, b"");
|
||
|
|
/// ```
|
||
|
|
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
|
||
|
|
read_until(self, byte, buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Read all bytes until a newline (the 0xA byte) is reached, and append
|
||
|
|
/// them to the provided buffer.
|
||
|
|
///
|
||
|
|
/// This function will read bytes from the underlying stream until the
|
||
|
|
/// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
|
||
|
|
/// up to, and including, the delimiter (if found) will be appended to
|
||
|
|
/// `buf`.
|
||
|
|
///
|
||
|
|
/// If successful, this function will return the total number of bytes read.
|
||
|
|
///
|
||
|
|
/// If this function returns `Ok(0)`, the stream has reached EOF.
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// This function has the same error semantics as [`read_until`] and will
|
||
|
|
/// also return an error if the read bytes are not valid UTF-8. If an I/O
|
||
|
|
/// error is encountered then `buf` may contain some bytes already read in
|
||
|
|
/// the event that all data read so far was valid UTF-8.
|
||
|
|
///
|
||
|
|
/// [`read_until`]: #method.read_until
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
|
||
|
|
/// this example, we use [`Cursor`] to read all the lines in a byte slice:
|
||
|
|
///
|
||
|
|
/// [`Cursor`]: struct.Cursor.html
|
||
|
|
///
|
||
|
|
/// ```
|
||
|
|
/// use std::io::{self, BufRead};
|
||
|
|
///
|
||
|
|
/// let mut cursor = io::Cursor::new(b"foo\nbar");
|
||
|
|
/// let mut buf = String::new();
|
||
|
|
///
|
||
|
|
/// // cursor is at 'f'
|
||
|
|
/// let num_bytes = cursor.read_line(&mut buf)
|
||
|
|
/// .expect("reading from cursor won't fail");
|
||
|
|
/// assert_eq!(num_bytes, 4);
|
||
|
|
/// assert_eq!(buf, "foo\n");
|
||
|
|
/// buf.clear();
|
||
|
|
///
|
||
|
|
/// // cursor is at 'b'
|
||
|
|
/// let num_bytes = cursor.read_line(&mut buf)
|
||
|
|
/// .expect("reading from cursor won't fail");
|
||
|
|
/// assert_eq!(num_bytes, 3);
|
||
|
|
/// assert_eq!(buf, "bar");
|
||
|
|
/// buf.clear();
|
||
|
|
///
|
||
|
|
/// // cursor is at EOF
|
||
|
|
/// let num_bytes = cursor.read_line(&mut buf)
|
||
|
|
/// .expect("reading from cursor won't fail");
|
||
|
|
/// assert_eq!(num_bytes, 0);
|
||
|
|
/// assert_eq!(buf, "");
|
||
|
|
/// ```
|
||
|
|
fn read_line(&mut self, buf: &mut String) -> Result<usize> {
|
||
|
|
// Note that we are not calling the `.read_until` method here, but
|
||
|
|
// rather our hardcoded implementation. For more details as to why, see
|
||
|
|
// the comments in `read_to_end`.
|
||
|
|
append_to_string(buf, |b| read_until(self, b'\n', b))
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Returns an iterator over the contents of this reader split on the byte
|
||
|
|
/// `byte`.
|
||
|
|
///
|
||
|
|
/// The iterator returned from this function will return instances of
|
||
|
|
/// [`io::Result`]`<`[`Vec<u8>`]`>`. Each vector returned will *not* have
|
||
|
|
/// the delimiter byte at the end.
|
||
|
|
///
|
||
|
|
/// This function will yield errors whenever [`read_until`] would have
|
||
|
|
/// also yielded an error.
|
||
|
|
///
|
||
|
|
/// [`io::Result`]: type.Result.html
|
||
|
|
/// [`Vec<u8>`]: ../vec/struct.Vec.html
|
||
|
|
/// [`read_until`]: #method.read_until
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
|
||
|
|
/// this example, we use [`Cursor`] to iterate over all hyphen delimited
|
||
|
|
/// segments in a byte slice
|
||
|
|
///
|
||
|
|
/// [`Cursor`]: struct.Cursor.html
|
||
|
|
///
|
||
|
|
/// ```
|
||
|
|
/// use std::io::{self, BufRead};
|
||
|
|
///
|
||
|
|
/// let cursor = io::Cursor::new(b"lorem-ipsum-dolor");
|
||
|
|
///
|
||
|
|
/// let mut split_iter = cursor.split(b'-').map(|l| l.unwrap());
|
||
|
|
/// assert_eq!(split_iter.next(), Some(b"lorem".to_vec()));
|
||
|
|
/// assert_eq!(split_iter.next(), Some(b"ipsum".to_vec()));
|
||
|
|
/// assert_eq!(split_iter.next(), Some(b"dolor".to_vec()));
|
||
|
|
/// assert_eq!(split_iter.next(), None);
|
||
|
|
/// ```
|
||
|
|
fn split(self, byte: u8) -> Split<Self>
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
Split { buf: self, delim: byte }
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Returns an iterator over the lines of this reader.
|
||
|
|
///
|
||
|
|
/// The iterator returned from this function will yield instances of
|
||
|
|
/// [`io::Result`]`<`[`String`]`>`. Each string returned will *not* have a newline
|
||
|
|
/// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
|
||
|
|
///
|
||
|
|
/// [`io::Result`]: type.Result.html
|
||
|
|
/// [`String`]: ../string/struct.String.html
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
|
||
|
|
/// this example, we use [`Cursor`] to iterate over all the lines in a byte
|
||
|
|
/// slice.
|
||
|
|
///
|
||
|
|
/// [`Cursor`]: struct.Cursor.html
|
||
|
|
///
|
||
|
|
/// ```
|
||
|
|
/// use std::io::{self, BufRead};
|
||
|
|
///
|
||
|
|
/// let cursor = io::Cursor::new(b"lorem\nipsum\r\ndolor");
|
||
|
|
///
|
||
|
|
/// let mut lines_iter = cursor.lines().map(|l| l.unwrap());
|
||
|
|
/// assert_eq!(lines_iter.next(), Some(String::from("lorem")));
|
||
|
|
/// assert_eq!(lines_iter.next(), Some(String::from("ipsum")));
|
||
|
|
/// assert_eq!(lines_iter.next(), Some(String::from("dolor")));
|
||
|
|
/// assert_eq!(lines_iter.next(), None);
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// # Errors
|
||
|
|
///
|
||
|
|
/// Each line of the iterator has the same error semantics as [`BufRead::read_line`].
|
||
|
|
///
|
||
|
|
/// [`BufRead::read_line`]: trait.BufRead.html#method.read_line
|
||
|
|
fn lines(self) -> Lines<Self>
|
||
|
|
where
|
||
|
|
Self: Sized,
|
||
|
|
{
|
||
|
|
Lines { buf: self }
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Adaptor to chain together two readers.
|
||
|
|
///
|
||
|
|
/// This struct is generally created by calling [`chain`] on a reader.
|
||
|
|
/// Please see the documentation of [`chain`] for more details.
|
||
|
|
///
|
||
|
|
/// [`chain`]: trait.Read.html#method.chain
|
||
|
|
pub struct Chain<T, U> {
|
||
|
|
first: T,
|
||
|
|
second: U,
|
||
|
|
done_first: bool,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T, U> Chain<T, U> {
|
||
|
|
/// Consumes the `Chain`, returning the wrapped readers.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut foo_file = File::open("foo.txt")?;
|
||
|
|
/// let mut bar_file = File::open("bar.txt")?;
|
||
|
|
///
|
||
|
|
/// let chain = foo_file.chain(bar_file);
|
||
|
|
/// let (foo_file, bar_file) = chain.into_inner();
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn into_inner(self) -> (T, U) {
|
||
|
|
(self.first, self.second)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Gets references to the underlying readers in this `Chain`.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut foo_file = File::open("foo.txt")?;
|
||
|
|
/// let mut bar_file = File::open("bar.txt")?;
|
||
|
|
///
|
||
|
|
/// let chain = foo_file.chain(bar_file);
|
||
|
|
/// let (foo_file, bar_file) = chain.get_ref();
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn get_ref(&self) -> (&T, &U) {
|
||
|
|
(&self.first, &self.second)
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Gets mutable references to the underlying readers in this `Chain`.
|
||
|
|
///
|
||
|
|
/// Care should be taken to avoid modifying the internal I/O state of the
|
||
|
|
/// underlying readers as doing so may corrupt the internal state of this
|
||
|
|
/// `Chain`.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut foo_file = File::open("foo.txt")?;
|
||
|
|
/// let mut bar_file = File::open("bar.txt")?;
|
||
|
|
///
|
||
|
|
/// let mut chain = foo_file.chain(bar_file);
|
||
|
|
/// let (foo_file, bar_file) = chain.get_mut();
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn get_mut(&mut self) -> (&mut T, &mut U) {
|
||
|
|
(&mut self.first, &mut self.second)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T: fmt::Debug, U: fmt::Debug> fmt::Debug for Chain<T, U> {
|
||
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
|
|
f.debug_struct("Chain").field("t", &self.first).field("u", &self.second).finish()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T: Read, U: Read> Read for Chain<T, U> {
|
||
|
|
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
|
||
|
|
if !self.done_first {
|
||
|
|
match self.first.read(buf)? {
|
||
|
|
0 if !buf.is_empty() => self.done_first = true,
|
||
|
|
n => return Ok(n),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
self.second.read(buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
unsafe fn initializer(&self) -> Initializer {
|
||
|
|
let initializer = self.first.initializer();
|
||
|
|
if initializer.should_initialize() { initializer } else { self.second.initializer() }
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
|
||
|
|
fn fill_buf(&mut self) -> Result<&[u8]> {
|
||
|
|
if !self.done_first {
|
||
|
|
match self.first.fill_buf()? {
|
||
|
|
buf if buf.is_empty() => {
|
||
|
|
self.done_first = true;
|
||
|
|
}
|
||
|
|
buf => return Ok(buf),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
self.second.fill_buf()
|
||
|
|
}
|
||
|
|
|
||
|
|
fn consume(&mut self, amt: usize) {
|
||
|
|
if !self.done_first { self.first.consume(amt) } else { self.second.consume(amt) }
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Reader adaptor which limits the bytes read from an underlying reader.
|
||
|
|
///
|
||
|
|
/// This struct is generally created by calling [`take`] on a reader.
|
||
|
|
/// Please see the documentation of [`take`] for more details.
|
||
|
|
///
|
||
|
|
/// [`take`]: trait.Read.html#method.take
|
||
|
|
#[derive(Debug)]
|
||
|
|
pub struct Take<T> {
|
||
|
|
inner: T,
|
||
|
|
limit: u64,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T> Take<T> {
|
||
|
|
/// Returns the number of bytes that can be read before this instance will
|
||
|
|
/// return EOF.
|
||
|
|
///
|
||
|
|
/// # Note
|
||
|
|
///
|
||
|
|
/// This instance may reach `EOF` after reading fewer bytes than indicated by
|
||
|
|
/// this method if the underlying [`Read`] instance reaches EOF.
|
||
|
|
///
|
||
|
|
/// [`Read`]: ../../std/io/trait.Read.html
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let f = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// // read at most five bytes
|
||
|
|
/// let handle = f.take(5);
|
||
|
|
///
|
||
|
|
/// println!("limit: {}", handle.limit());
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn limit(&self) -> u64 {
|
||
|
|
self.limit
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Sets the number of bytes that can be read before this instance will
|
||
|
|
/// return EOF. This is the same as constructing a new `Take` instance, so
|
||
|
|
/// the amount of bytes read and the previous limit value don't matter when
|
||
|
|
/// calling this method.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let f = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// // read at most five bytes
|
||
|
|
/// let mut handle = f.take(5);
|
||
|
|
/// handle.set_limit(10);
|
||
|
|
///
|
||
|
|
/// assert_eq!(handle.limit(), 10);
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn set_limit(&mut self, limit: u64) {
|
||
|
|
self.limit = limit;
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Consumes the `Take`, returning the wrapped reader.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut file = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// let mut buffer = [0; 5];
|
||
|
|
/// let mut handle = file.take(5);
|
||
|
|
/// handle.read(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// let file = handle.into_inner();
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn into_inner(self) -> T {
|
||
|
|
self.inner
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Gets a reference to the underlying reader.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut file = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// let mut buffer = [0; 5];
|
||
|
|
/// let mut handle = file.take(5);
|
||
|
|
/// handle.read(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// let file = handle.get_ref();
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn get_ref(&self) -> &T {
|
||
|
|
&self.inner
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Gets a mutable reference to the underlying reader.
|
||
|
|
///
|
||
|
|
/// Care should be taken to avoid modifying the internal I/O state of the
|
||
|
|
/// underlying reader as doing so may corrupt the internal limit of this
|
||
|
|
/// `Take`.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```no_run
|
||
|
|
/// use std::io;
|
||
|
|
/// use std::io::prelude::*;
|
||
|
|
/// use std::fs::File;
|
||
|
|
///
|
||
|
|
/// fn main() -> io::Result<()> {
|
||
|
|
/// let mut file = File::open("foo.txt")?;
|
||
|
|
///
|
||
|
|
/// let mut buffer = [0; 5];
|
||
|
|
/// let mut handle = file.take(5);
|
||
|
|
/// handle.read(&mut buffer)?;
|
||
|
|
///
|
||
|
|
/// let file = handle.get_mut();
|
||
|
|
/// Ok(())
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
pub fn get_mut(&mut self) -> &mut T {
|
||
|
|
&mut self.inner
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T: Read> Read for Take<T> {
|
||
|
|
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
|
||
|
|
// Don't call into inner reader at all at EOF because it may still block
|
||
|
|
if self.limit == 0 {
|
||
|
|
return Ok(0);
|
||
|
|
}
|
||
|
|
|
||
|
|
let max = cmp::min(buf.len() as u64, self.limit) as usize;
|
||
|
|
let n = self.inner.read(&mut buf[..max])?;
|
||
|
|
self.limit -= n as u64;
|
||
|
|
Ok(n)
|
||
|
|
}
|
||
|
|
|
||
|
|
unsafe fn initializer(&self) -> Initializer {
|
||
|
|
self.inner.initializer()
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
|
||
|
|
// Pass in a reservation_size closure that respects the current value
|
||
|
|
// of limit for each read. If we hit the read limit, this prevents the
|
||
|
|
// final zero-byte read from allocating again.
|
||
|
|
read_to_end_with_reservation(self, buf, |self_| cmp::min(self_.limit, 32) as usize)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
impl<T: BufRead> BufRead for Take<T> {
|
||
|
|
fn fill_buf(&mut self) -> Result<&[u8]> {
|
||
|
|
// Don't call into inner reader at all at EOF because it may still block
|
||
|
|
if self.limit == 0 {
|
||
|
|
return Ok(&[]);
|
||
|
|
}
|
||
|
|
|
||
|
|
let buf = self.inner.fill_buf()?;
|
||
|
|
let cap = cmp::min(buf.len() as u64, self.limit) as usize;
|
||
|
|
Ok(&buf[..cap])
|
||
|
|
}
|
||
|
|
|
||
|
|
fn consume(&mut self, amt: usize) {
|
||
|
|
// Don't let callers reset the limit by passing an overlarge value
|
||
|
|
let amt = cmp::min(amt as u64, self.limit) as usize;
|
||
|
|
self.limit -= amt as u64;
|
||
|
|
self.inner.consume(amt);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// An iterator over `u8` values of a reader.
|
||
|
|
///
|
||
|
|
/// This struct is generally created by calling [`bytes`] on a reader.
|
||
|
|
/// Please see the documentation of [`bytes`] for more details.
|
||
|
|
///
|
||
|
|
/// [`bytes`]: trait.Read.html#method.bytes
|
||
|
|
#[derive(Debug)]
|
||
|
|
pub struct Bytes<R> {
|
||
|
|
inner: R,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<R: Read> Iterator for Bytes<R> {
|
||
|
|
type Item = Result<u8>;
|
||
|
|
|
||
|
|
fn next(&mut self) -> Option<Result<u8>> {
|
||
|
|
let mut byte = 0;
|
||
|
|
loop {
|
||
|
|
return match self.inner.read(slice::from_mut(&mut byte)) {
|
||
|
|
Ok(0) => None,
|
||
|
|
Ok(..) => Some(Ok(byte)),
|
||
|
|
Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
|
||
|
|
Err(e) => Some(Err(e)),
|
||
|
|
};
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// An iterator over the contents of an instance of `BufRead` split on a
|
||
|
|
/// particular byte.
|
||
|
|
///
|
||
|
|
/// This struct is generally created by calling [`split`] on a `BufRead`.
|
||
|
|
/// Please see the documentation of [`split`] for more details.
|
||
|
|
///
|
||
|
|
/// [`split`]: trait.BufRead.html#method.split
|
||
|
|
#[derive(Debug)]
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
pub struct Split<B> {
|
||
|
|
buf: B,
|
||
|
|
delim: u8,
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
impl<B: BufRead> Iterator for Split<B> {
|
||
|
|
type Item = Result<Vec<u8>>;
|
||
|
|
|
||
|
|
fn next(&mut self) -> Option<Result<Vec<u8>>> {
|
||
|
|
let mut buf = Vec::new();
|
||
|
|
match self.buf.read_until(self.delim, &mut buf) {
|
||
|
|
Ok(0) => None,
|
||
|
|
Ok(_n) => {
|
||
|
|
if buf[buf.len() - 1] == self.delim {
|
||
|
|
buf.pop();
|
||
|
|
}
|
||
|
|
Some(Ok(buf))
|
||
|
|
}
|
||
|
|
Err(e) => Some(Err(e)),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// An iterator over the lines of an instance of `BufRead`.
|
||
|
|
///
|
||
|
|
/// This struct is generally created by calling [`lines`] on a `BufRead`.
|
||
|
|
/// Please see the documentation of [`lines`] for more details.
|
||
|
|
///
|
||
|
|
/// [`lines`]: trait.BufRead.html#method.lines
|
||
|
|
#[derive(Debug)]
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
pub struct Lines<B> {
|
||
|
|
buf: B,
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(feature="collections")]
|
||
|
|
impl<B: BufRead> Iterator for Lines<B> {
|
||
|
|
type Item = Result<String>;
|
||
|
|
|
||
|
|
fn next(&mut self) -> Option<Result<String>> {
|
||
|
|
let mut buf = String::new();
|
||
|
|
match self.buf.read_line(&mut buf) {
|
||
|
|
Ok(0) => None,
|
||
|
|
Ok(_n) => {
|
||
|
|
if buf.ends_with('\n') {
|
||
|
|
buf.pop();
|
||
|
|
if buf.ends_with('\r') {
|
||
|
|
buf.pop();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
Some(Ok(buf))
|
||
|
|
}
|
||
|
|
Err(e) => Some(Err(e)),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(test)]
|
||
|
|
mod tests {
|
||
|
|
use super::{repeat, Cursor, SeekFrom};
|
||
|
|
use crate::cmp::{self, min};
|
||
|
|
use crate::io::prelude::*;
|
||
|
|
use crate::io::{self, IoSlice, IoSliceMut};
|
||
|
|
use crate::ops::Deref;
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
#[cfg_attr(target_os = "emscripten", ignore)]
|
||
|
|
fn read_until() {
|
||
|
|
let mut buf = Cursor::new(&b"12"[..]);
|
||
|
|
let mut v = Vec::new();
|
||
|
|
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
|
||
|
|
assert_eq!(v, b"12");
|
||
|
|
|
||
|
|
let mut buf = Cursor::new(&b"1233"[..]);
|
||
|
|
let mut v = Vec::new();
|
||
|
|
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
|
||
|
|
assert_eq!(v, b"123");
|
||
|
|
v.truncate(0);
|
||
|
|
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
|
||
|
|
assert_eq!(v, b"3");
|
||
|
|
v.truncate(0);
|
||
|
|
assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
|
||
|
|
assert_eq!(v, []);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn split() {
|
||
|
|
let buf = Cursor::new(&b"12"[..]);
|
||
|
|
let mut s = buf.split(b'3');
|
||
|
|
assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
|
||
|
|
assert!(s.next().is_none());
|
||
|
|
|
||
|
|
let buf = Cursor::new(&b"1233"[..]);
|
||
|
|
let mut s = buf.split(b'3');
|
||
|
|
assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
|
||
|
|
assert_eq!(s.next().unwrap().unwrap(), vec![]);
|
||
|
|
assert!(s.next().is_none());
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn read_line() {
|
||
|
|
let mut buf = Cursor::new(&b"12"[..]);
|
||
|
|
let mut v = String::new();
|
||
|
|
assert_eq!(buf.read_line(&mut v).unwrap(), 2);
|
||
|
|
assert_eq!(v, "12");
|
||
|
|
|
||
|
|
let mut buf = Cursor::new(&b"12\n\n"[..]);
|
||
|
|
let mut v = String::new();
|
||
|
|
assert_eq!(buf.read_line(&mut v).unwrap(), 3);
|
||
|
|
assert_eq!(v, "12\n");
|
||
|
|
v.truncate(0);
|
||
|
|
assert_eq!(buf.read_line(&mut v).unwrap(), 1);
|
||
|
|
assert_eq!(v, "\n");
|
||
|
|
v.truncate(0);
|
||
|
|
assert_eq!(buf.read_line(&mut v).unwrap(), 0);
|
||
|
|
assert_eq!(v, "");
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn lines() {
|
||
|
|
let buf = Cursor::new(&b"12\r"[..]);
|
||
|
|
let mut s = buf.lines();
|
||
|
|
assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
|
||
|
|
assert!(s.next().is_none());
|
||
|
|
|
||
|
|
let buf = Cursor::new(&b"12\r\n\n"[..]);
|
||
|
|
let mut s = buf.lines();
|
||
|
|
assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
|
||
|
|
assert_eq!(s.next().unwrap().unwrap(), "".to_string());
|
||
|
|
assert!(s.next().is_none());
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn read_to_end() {
|
||
|
|
let mut c = Cursor::new(&b""[..]);
|
||
|
|
let mut v = Vec::new();
|
||
|
|
assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
|
||
|
|
assert_eq!(v, []);
|
||
|
|
|
||
|
|
let mut c = Cursor::new(&b"1"[..]);
|
||
|
|
let mut v = Vec::new();
|
||
|
|
assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
|
||
|
|
assert_eq!(v, b"1");
|
||
|
|
|
||
|
|
let cap = 1024 * 1024;
|
||
|
|
let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
|
||
|
|
let mut v = Vec::new();
|
||
|
|
let (a, b) = data.split_at(data.len() / 2);
|
||
|
|
assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
|
||
|
|
assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
|
||
|
|
assert_eq!(v, data);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn read_to_string() {
|
||
|
|
let mut c = Cursor::new(&b""[..]);
|
||
|
|
let mut v = String::new();
|
||
|
|
assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
|
||
|
|
assert_eq!(v, "");
|
||
|
|
|
||
|
|
let mut c = Cursor::new(&b"1"[..]);
|
||
|
|
let mut v = String::new();
|
||
|
|
assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
|
||
|
|
assert_eq!(v, "1");
|
||
|
|
|
||
|
|
let mut c = Cursor::new(&b"\xff"[..]);
|
||
|
|
let mut v = String::new();
|
||
|
|
assert!(c.read_to_string(&mut v).is_err());
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn read_exact() {
|
||
|
|
let mut buf = [0; 4];
|
||
|
|
|
||
|
|
let mut c = Cursor::new(&b""[..]);
|
||
|
|
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
|
||
|
|
|
||
|
|
let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
|
||
|
|
c.read_exact(&mut buf).unwrap();
|
||
|
|
assert_eq!(&buf, b"1234");
|
||
|
|
c.read_exact(&mut buf).unwrap();
|
||
|
|
assert_eq!(&buf, b"5678");
|
||
|
|
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn read_exact_slice() {
|
||
|
|
let mut buf = [0; 4];
|
||
|
|
|
||
|
|
let mut c = &b""[..];
|
||
|
|
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
|
||
|
|
|
||
|
|
let mut c = &b"123"[..];
|
||
|
|
assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
|
||
|
|
// make sure the optimized (early returning) method is being used
|
||
|
|
assert_eq!(&buf, &[0; 4]);
|
||
|
|
|
||
|
|
let mut c = &b"1234"[..];
|
||
|
|
c.read_exact(&mut buf).unwrap();
|
||
|
|
assert_eq!(&buf, b"1234");
|
||
|
|
|
||
|
|
let mut c = &b"56789"[..];
|
||
|
|
c.read_exact(&mut buf).unwrap();
|
||
|
|
assert_eq!(&buf, b"5678");
|
||
|
|
assert_eq!(c, b"9");
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn take_eof() {
|
||
|
|
struct R;
|
||
|
|
|
||
|
|
impl Read for R {
|
||
|
|
fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
|
||
|
|
Err(io::Error::new(io::ErrorKind::Other, ""))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
impl BufRead for R {
|
||
|
|
fn fill_buf(&mut self) -> io::Result<&[u8]> {
|
||
|
|
Err(io::Error::new(io::ErrorKind::Other, ""))
|
||
|
|
}
|
||
|
|
fn consume(&mut self, _amt: usize) {}
|
||
|
|
}
|
||
|
|
|
||
|
|
let mut buf = [0; 1];
|
||
|
|
assert_eq!(0, R.take(0).read(&mut buf).unwrap());
|
||
|
|
assert_eq!(b"", R.take(0).fill_buf().unwrap());
|
||
|
|
}
|
||
|
|
|
||
|
|
fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
|
||
|
|
let mut cat = Vec::new();
|
||
|
|
loop {
|
||
|
|
let consume = {
|
||
|
|
let buf1 = br1.fill_buf().unwrap();
|
||
|
|
let buf2 = br2.fill_buf().unwrap();
|
||
|
|
let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
|
||
|
|
assert_eq!(buf1[..minlen], buf2[..minlen]);
|
||
|
|
cat.extend_from_slice(&buf1[..minlen]);
|
||
|
|
minlen
|
||
|
|
};
|
||
|
|
if consume == 0 {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
br1.consume(consume);
|
||
|
|
br2.consume(consume);
|
||
|
|
}
|
||
|
|
assert_eq!(br1.fill_buf().unwrap().len(), 0);
|
||
|
|
assert_eq!(br2.fill_buf().unwrap().len(), 0);
|
||
|
|
assert_eq!(&cat[..], &exp[..])
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn chain_bufread() {
|
||
|
|
let testdata = b"ABCDEFGHIJKL";
|
||
|
|
let chain1 =
|
||
|
|
(&testdata[..3]).chain(&testdata[3..6]).chain(&testdata[6..9]).chain(&testdata[9..]);
|
||
|
|
let chain2 = (&testdata[..4]).chain(&testdata[4..8]).chain(&testdata[8..]);
|
||
|
|
cmp_bufread(chain1, chain2, &testdata[..]);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn chain_zero_length_read_is_not_eof() {
|
||
|
|
let a = b"A";
|
||
|
|
let b = b"B";
|
||
|
|
let mut s = String::new();
|
||
|
|
let mut chain = (&a[..]).chain(&b[..]);
|
||
|
|
chain.read(&mut []).unwrap();
|
||
|
|
chain.read_to_string(&mut s).unwrap();
|
||
|
|
assert_eq!("AB", s);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[bench]
|
||
|
|
#[cfg_attr(target_os = "emscripten", ignore)]
|
||
|
|
fn bench_read_to_end(b: &mut test::Bencher) {
|
||
|
|
b.iter(|| {
|
||
|
|
let mut lr = repeat(1).take(10000000);
|
||
|
|
let mut vec = Vec::with_capacity(1024);
|
||
|
|
super::read_to_end(&mut lr, &mut vec)
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn seek_len() -> io::Result<()> {
|
||
|
|
let mut c = Cursor::new(vec![0; 15]);
|
||
|
|
assert_eq!(c.stream_len()?, 15);
|
||
|
|
|
||
|
|
c.seek(SeekFrom::End(0))?;
|
||
|
|
let old_pos = c.stream_position()?;
|
||
|
|
assert_eq!(c.stream_len()?, 15);
|
||
|
|
assert_eq!(c.stream_position()?, old_pos);
|
||
|
|
|
||
|
|
c.seek(SeekFrom::Start(7))?;
|
||
|
|
c.seek(SeekFrom::Current(2))?;
|
||
|
|
let old_pos = c.stream_position()?;
|
||
|
|
assert_eq!(c.stream_len()?, 15);
|
||
|
|
assert_eq!(c.stream_position()?, old_pos);
|
||
|
|
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn seek_position() -> io::Result<()> {
|
||
|
|
// All `asserts` are duplicated here to make sure the method does not
|
||
|
|
// change anything about the seek state.
|
||
|
|
let mut c = Cursor::new(vec![0; 15]);
|
||
|
|
assert_eq!(c.stream_position()?, 0);
|
||
|
|
assert_eq!(c.stream_position()?, 0);
|
||
|
|
|
||
|
|
c.seek(SeekFrom::End(0))?;
|
||
|
|
assert_eq!(c.stream_position()?, 15);
|
||
|
|
assert_eq!(c.stream_position()?, 15);
|
||
|
|
|
||
|
|
c.seek(SeekFrom::Start(7))?;
|
||
|
|
c.seek(SeekFrom::Current(2))?;
|
||
|
|
assert_eq!(c.stream_position()?, 9);
|
||
|
|
assert_eq!(c.stream_position()?, 9);
|
||
|
|
|
||
|
|
c.seek(SeekFrom::End(-3))?;
|
||
|
|
c.seek(SeekFrom::Current(1))?;
|
||
|
|
c.seek(SeekFrom::Current(-5))?;
|
||
|
|
assert_eq!(c.stream_position()?, 8);
|
||
|
|
assert_eq!(c.stream_position()?, 8);
|
||
|
|
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
|
||
|
|
// A simple example reader which uses the default implementation of
|
||
|
|
// read_to_end.
|
||
|
|
struct ExampleSliceReader<'a> {
|
||
|
|
slice: &'a [u8],
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<'a> Read for ExampleSliceReader<'a> {
|
||
|
|
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
|
||
|
|
let len = cmp::min(self.slice.len(), buf.len());
|
||
|
|
buf[..len].copy_from_slice(&self.slice[..len]);
|
||
|
|
self.slice = &self.slice[len..];
|
||
|
|
Ok(len)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn test_read_to_end_capacity() -> io::Result<()> {
|
||
|
|
let input = &b"foo"[..];
|
||
|
|
|
||
|
|
// read_to_end() generally needs to over-allocate, both for efficiency
|
||
|
|
// and so that it can distinguish EOF. Assert that this is the case
|
||
|
|
// with this simple ExampleSliceReader struct, which uses the default
|
||
|
|
// implementation of read_to_end. Even though vec1 is allocated with
|
||
|
|
// exactly enough capacity for the read, read_to_end will allocate more
|
||
|
|
// space here.
|
||
|
|
let mut vec1 = Vec::with_capacity(input.len());
|
||
|
|
ExampleSliceReader { slice: input }.read_to_end(&mut vec1)?;
|
||
|
|
assert_eq!(vec1.len(), input.len());
|
||
|
|
assert!(vec1.capacity() > input.len(), "allocated more");
|
||
|
|
|
||
|
|
// However, std::io::Take includes an implementation of read_to_end
|
||
|
|
// that will not allocate when the limit has already been reached. In
|
||
|
|
// this case, vec2 never grows.
|
||
|
|
let mut vec2 = Vec::with_capacity(input.len());
|
||
|
|
ExampleSliceReader { slice: input }.take(input.len() as u64).read_to_end(&mut vec2)?;
|
||
|
|
assert_eq!(vec2.len(), input.len());
|
||
|
|
assert_eq!(vec2.capacity(), input.len(), "did not allocate more");
|
||
|
|
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn io_slice_mut_advance() {
|
||
|
|
let mut buf1 = [1; 8];
|
||
|
|
let mut buf2 = [2; 16];
|
||
|
|
let mut buf3 = [3; 8];
|
||
|
|
let mut bufs = &mut [
|
||
|
|
IoSliceMut::new(&mut buf1),
|
||
|
|
IoSliceMut::new(&mut buf2),
|
||
|
|
IoSliceMut::new(&mut buf3),
|
||
|
|
][..];
|
||
|
|
|
||
|
|
// Only in a single buffer..
|
||
|
|
bufs = IoSliceMut::advance(bufs, 1);
|
||
|
|
assert_eq!(bufs[0].deref(), [1; 7].as_ref());
|
||
|
|
assert_eq!(bufs[1].deref(), [2; 16].as_ref());
|
||
|
|
assert_eq!(bufs[2].deref(), [3; 8].as_ref());
|
||
|
|
|
||
|
|
// Removing a buffer, leaving others as is.
|
||
|
|
bufs = IoSliceMut::advance(bufs, 7);
|
||
|
|
assert_eq!(bufs[0].deref(), [2; 16].as_ref());
|
||
|
|
assert_eq!(bufs[1].deref(), [3; 8].as_ref());
|
||
|
|
|
||
|
|
// Removing a buffer and removing from the next buffer.
|
||
|
|
bufs = IoSliceMut::advance(bufs, 18);
|
||
|
|
assert_eq!(bufs[0].deref(), [3; 6].as_ref());
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn io_slice_mut_advance_empty_slice() {
|
||
|
|
let empty_bufs = &mut [][..];
|
||
|
|
// Shouldn't panic.
|
||
|
|
IoSliceMut::advance(empty_bufs, 1);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn io_slice_mut_advance_beyond_total_length() {
|
||
|
|
let mut buf1 = [1; 8];
|
||
|
|
let mut bufs = &mut [IoSliceMut::new(&mut buf1)][..];
|
||
|
|
|
||
|
|
// Going beyond the total length should be ok.
|
||
|
|
bufs = IoSliceMut::advance(bufs, 9);
|
||
|
|
assert!(bufs.is_empty());
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn io_slice_advance() {
|
||
|
|
let buf1 = [1; 8];
|
||
|
|
let buf2 = [2; 16];
|
||
|
|
let buf3 = [3; 8];
|
||
|
|
let mut bufs = &mut [IoSlice::new(&buf1), IoSlice::new(&buf2), IoSlice::new(&buf3)][..];
|
||
|
|
|
||
|
|
// Only in a single buffer..
|
||
|
|
bufs = IoSlice::advance(bufs, 1);
|
||
|
|
assert_eq!(bufs[0].deref(), [1; 7].as_ref());
|
||
|
|
assert_eq!(bufs[1].deref(), [2; 16].as_ref());
|
||
|
|
assert_eq!(bufs[2].deref(), [3; 8].as_ref());
|
||
|
|
|
||
|
|
// Removing a buffer, leaving others as is.
|
||
|
|
bufs = IoSlice::advance(bufs, 7);
|
||
|
|
assert_eq!(bufs[0].deref(), [2; 16].as_ref());
|
||
|
|
assert_eq!(bufs[1].deref(), [3; 8].as_ref());
|
||
|
|
|
||
|
|
// Removing a buffer and removing from the next buffer.
|
||
|
|
bufs = IoSlice::advance(bufs, 18);
|
||
|
|
assert_eq!(bufs[0].deref(), [3; 6].as_ref());
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn io_slice_advance_empty_slice() {
|
||
|
|
let empty_bufs = &mut [][..];
|
||
|
|
// Shouldn't panic.
|
||
|
|
IoSlice::advance(empty_bufs, 1);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn io_slice_advance_beyond_total_length() {
|
||
|
|
let buf1 = [1; 8];
|
||
|
|
let mut bufs = &mut [IoSlice::new(&buf1)][..];
|
||
|
|
|
||
|
|
// Going beyond the total length should be ok.
|
||
|
|
bufs = IoSlice::advance(bufs, 9);
|
||
|
|
assert!(bufs.is_empty());
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Create a new writer that reads from at most `n_bufs` and reads
|
||
|
|
/// `per_call` bytes (in total) per call to write.
|
||
|
|
fn test_writer(n_bufs: usize, per_call: usize) -> TestWriter {
|
||
|
|
TestWriter { n_bufs, per_call, written: Vec::new() }
|
||
|
|
}
|
||
|
|
|
||
|
|
struct TestWriter {
|
||
|
|
n_bufs: usize,
|
||
|
|
per_call: usize,
|
||
|
|
written: Vec<u8>,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl Write for TestWriter {
|
||
|
|
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
|
||
|
|
self.write_vectored(&[IoSlice::new(buf)])
|
||
|
|
}
|
||
|
|
|
||
|
|
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
|
||
|
|
let mut left = self.per_call;
|
||
|
|
let mut written = 0;
|
||
|
|
for buf in bufs.iter().take(self.n_bufs) {
|
||
|
|
let n = min(left, buf.len());
|
||
|
|
self.written.extend_from_slice(&buf[0..n]);
|
||
|
|
left -= n;
|
||
|
|
written += n;
|
||
|
|
}
|
||
|
|
Ok(written)
|
||
|
|
}
|
||
|
|
|
||
|
|
fn flush(&mut self) -> io::Result<()> {
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn test_writer_read_from_one_buf() {
|
||
|
|
let mut writer = test_writer(1, 2);
|
||
|
|
|
||
|
|
assert_eq!(writer.write(&[]).unwrap(), 0);
|
||
|
|
assert_eq!(writer.write_vectored(&[]).unwrap(), 0);
|
||
|
|
|
||
|
|
// Read at most 2 bytes.
|
||
|
|
assert_eq!(writer.write(&[1, 1, 1]).unwrap(), 2);
|
||
|
|
let bufs = &[IoSlice::new(&[2, 2, 2])];
|
||
|
|
assert_eq!(writer.write_vectored(bufs).unwrap(), 2);
|
||
|
|
|
||
|
|
// Only read from first buf.
|
||
|
|
let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4, 4])];
|
||
|
|
assert_eq!(writer.write_vectored(bufs).unwrap(), 1);
|
||
|
|
|
||
|
|
assert_eq!(writer.written, &[1, 1, 2, 2, 3]);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn test_writer_read_from_multiple_bufs() {
|
||
|
|
let mut writer = test_writer(3, 3);
|
||
|
|
|
||
|
|
// Read at most 3 bytes from two buffers.
|
||
|
|
let bufs = &[IoSlice::new(&[1]), IoSlice::new(&[2, 2, 2])];
|
||
|
|
assert_eq!(writer.write_vectored(bufs).unwrap(), 3);
|
||
|
|
|
||
|
|
// Read at most 3 bytes from three buffers.
|
||
|
|
let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4]), IoSlice::new(&[5, 5])];
|
||
|
|
assert_eq!(writer.write_vectored(bufs).unwrap(), 3);
|
||
|
|
|
||
|
|
assert_eq!(writer.written, &[1, 2, 2, 3, 4, 5]);
|
||
|
|
}
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn test_write_all_vectored() {
|
||
|
|
#[rustfmt::skip] // Becomes unreadable otherwise.
|
||
|
|
let tests: Vec<(_, &'static [u8])> = vec![
|
||
|
|
(vec![], &[]),
|
||
|
|
(vec![IoSlice::new(&[1])], &[1]),
|
||
|
|
(vec![IoSlice::new(&[1, 2])], &[1, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 2, 3])], &[1, 2, 3]),
|
||
|
|
(vec![IoSlice::new(&[1, 2, 3, 4])], &[1, 2, 3, 4]),
|
||
|
|
(vec![IoSlice::new(&[1, 2, 3, 4, 5])], &[1, 2, 3, 4, 5]),
|
||
|
|
(vec![IoSlice::new(&[1]), IoSlice::new(&[2])], &[1, 2]),
|
||
|
|
(vec![IoSlice::new(&[1]), IoSlice::new(&[2, 2])], &[1, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2])], &[1, 1, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 2, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 2, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 1, 2, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 2, 2, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1, 1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 1, 2, 2, 2, 2]),
|
||
|
|
(vec![IoSlice::new(&[1]), IoSlice::new(&[2]), IoSlice::new(&[3])], &[1, 2, 3]),
|
||
|
|
(vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3])], &[1, 1, 2, 2, 3, 3]),
|
||
|
|
(vec![IoSlice::new(&[1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 2, 2, 3, 3, 3]),
|
||
|
|
(vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 1, 1, 2, 2, 2, 3, 3, 3]),
|
||
|
|
];
|
||
|
|
|
||
|
|
let writer_configs = &[(1, 1), (1, 2), (1, 3), (2, 2), (2, 3), (3, 3)];
|
||
|
|
|
||
|
|
for (n_bufs, per_call) in writer_configs.iter().copied() {
|
||
|
|
for (mut input, wanted) in tests.clone().into_iter() {
|
||
|
|
let mut writer = test_writer(n_bufs, per_call);
|
||
|
|
assert!(writer.write_all_vectored(&mut *input).is_ok());
|
||
|
|
assert_eq!(&*writer.written, &*wanted);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|