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85aaf69f | 1 | // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
1a4d82fc JJ |
2 | // file at the top-level directory of this distribution and at |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
1a4d82fc | 10 | |
85aaf69f | 11 | //! Traits, helpers, and type definitions for core I/O functionality. |
c1a9b12d SL |
12 | //! |
13 | //! The `std::io` module contains a number of common things you'll need | |
14 | //! when doing input and output. The most core part of this module is | |
c30ab7b3 | 15 | //! the [`Read`] and [`Write`] traits, which provide the |
c1a9b12d SL |
16 | //! most general interface for reading and writing input and output. |
17 | //! | |
c1a9b12d SL |
18 | //! # Read and Write |
19 | //! | |
c30ab7b3 | 20 | //! Because they are traits, [`Read`] and [`Write`] are implemented by a number |
b039eaaf SL |
21 | //! of other types, and you can implement them for your types too. As such, |
22 | //! you'll see a few different types of I/O throughout the documentation in | |
c30ab7b3 | 23 | //! this module: [`File`]s, [`TcpStream`]s, and sometimes even [`Vec<T>`]s. For |
cc61c64b | 24 | //! example, [`Read`] adds a [`read`][`Read::read`] method, which we can use on |
3b2f2976 | 25 | //! [`File`]s: |
c1a9b12d SL |
26 | //! |
27 | //! ``` | |
28 | //! use std::io; | |
29 | //! use std::io::prelude::*; | |
30 | //! use std::fs::File; | |
31 | //! | |
32 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 33 | //! let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
34 | //! let mut buffer = [0; 10]; |
35 | //! | |
36 | //! // read up to 10 bytes | |
32a655c1 | 37 | //! f.read(&mut buffer)?; |
c1a9b12d SL |
38 | //! |
39 | //! println!("The bytes: {:?}", buffer); | |
40 | //! # Ok(()) | |
41 | //! # } | |
42 | //! ``` | |
43 | //! | |
c30ab7b3 | 44 | //! [`Read`] and [`Write`] are so important, implementors of the two traits have a |
c1a9b12d | 45 | //! nickname: readers and writers. So you'll sometimes see 'a reader' instead |
c30ab7b3 | 46 | //! of 'a type that implements the [`Read`] trait'. Much easier! |
c1a9b12d SL |
47 | //! |
48 | //! ## Seek and BufRead | |
49 | //! | |
c30ab7b3 SL |
50 | //! Beyond that, there are two important traits that are provided: [`Seek`] |
51 | //! and [`BufRead`]. Both of these build on top of a reader to control | |
52 | //! how the reading happens. [`Seek`] lets you control where the next byte is | |
c1a9b12d SL |
53 | //! coming from: |
54 | //! | |
55 | //! ``` | |
56 | //! use std::io; | |
57 | //! use std::io::prelude::*; | |
58 | //! use std::io::SeekFrom; | |
59 | //! use std::fs::File; | |
60 | //! | |
61 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 62 | //! let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
63 | //! let mut buffer = [0; 10]; |
64 | //! | |
65 | //! // skip to the last 10 bytes of the file | |
32a655c1 | 66 | //! f.seek(SeekFrom::End(-10))?; |
c1a9b12d SL |
67 | //! |
68 | //! // read up to 10 bytes | |
32a655c1 | 69 | //! f.read(&mut buffer)?; |
c1a9b12d SL |
70 | //! |
71 | //! println!("The bytes: {:?}", buffer); | |
72 | //! # Ok(()) | |
73 | //! # } | |
74 | //! ``` | |
75 | //! | |
c30ab7b3 | 76 | //! [`BufRead`] uses an internal buffer to provide a number of other ways to read, but |
c1a9b12d SL |
77 | //! to show it off, we'll need to talk about buffers in general. Keep reading! |
78 | //! | |
79 | //! ## BufReader and BufWriter | |
80 | //! | |
81 | //! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be | |
82 | //! making near-constant calls to the operating system. To help with this, | |
c30ab7b3 | 83 | //! `std::io` comes with two structs, [`BufReader`] and [`BufWriter`], which wrap |
c1a9b12d SL |
84 | //! readers and writers. The wrapper uses a buffer, reducing the number of |
85 | //! calls and providing nicer methods for accessing exactly what you want. | |
86 | //! | |
c30ab7b3 | 87 | //! For example, [`BufReader`] works with the [`BufRead`] trait to add extra |
c1a9b12d SL |
88 | //! methods to any reader: |
89 | //! | |
90 | //! ``` | |
91 | //! use std::io; | |
92 | //! use std::io::prelude::*; | |
93 | //! use std::io::BufReader; | |
94 | //! use std::fs::File; | |
95 | //! | |
96 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 97 | //! let f = File::open("foo.txt")?; |
c1a9b12d SL |
98 | //! let mut reader = BufReader::new(f); |
99 | //! let mut buffer = String::new(); | |
100 | //! | |
101 | //! // read a line into buffer | |
32a655c1 | 102 | //! reader.read_line(&mut buffer)?; |
c1a9b12d SL |
103 | //! |
104 | //! println!("{}", buffer); | |
105 | //! # Ok(()) | |
106 | //! # } | |
107 | //! ``` | |
108 | //! | |
c30ab7b3 | 109 | //! [`BufWriter`] doesn't add any new ways of writing; it just buffers every call |
cc61c64b | 110 | //! to [`write`][`Write::write`]: |
c1a9b12d SL |
111 | //! |
112 | //! ``` | |
113 | //! use std::io; | |
114 | //! use std::io::prelude::*; | |
115 | //! use std::io::BufWriter; | |
116 | //! use std::fs::File; | |
117 | //! | |
118 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 119 | //! let f = File::create("foo.txt")?; |
c1a9b12d SL |
120 | //! { |
121 | //! let mut writer = BufWriter::new(f); | |
122 | //! | |
123 | //! // write a byte to the buffer | |
32a655c1 | 124 | //! writer.write(&[42])?; |
c1a9b12d SL |
125 | //! |
126 | //! } // the buffer is flushed once writer goes out of scope | |
127 | //! | |
128 | //! # Ok(()) | |
129 | //! # } | |
130 | //! ``` | |
131 | //! | |
c1a9b12d SL |
132 | //! ## Standard input and output |
133 | //! | |
134 | //! A very common source of input is standard input: | |
135 | //! | |
136 | //! ``` | |
137 | //! use std::io; | |
138 | //! | |
139 | //! # fn foo() -> io::Result<()> { | |
140 | //! let mut input = String::new(); | |
141 | //! | |
32a655c1 | 142 | //! io::stdin().read_line(&mut input)?; |
c1a9b12d SL |
143 | //! |
144 | //! println!("You typed: {}", input.trim()); | |
145 | //! # Ok(()) | |
146 | //! # } | |
147 | //! ``` | |
148 | //! | |
3b2f2976 XL |
149 | //! Note that you cannot use the [`?` operator] in functions that do not return |
150 | //! a [`Result<T, E>`][`Result`] (e.g. `main`). Instead, you can call [`.unwrap()`] | |
151 | //! or `match` on the return value to catch any possible errors: | |
cc61c64b XL |
152 | //! |
153 | //! ``` | |
154 | //! use std::io; | |
155 | //! | |
156 | //! let mut input = String::new(); | |
157 | //! | |
158 | //! io::stdin().read_line(&mut input).unwrap(); | |
159 | //! ``` | |
160 | //! | |
c1a9b12d SL |
161 | //! And a very common source of output is standard output: |
162 | //! | |
163 | //! ``` | |
164 | //! use std::io; | |
165 | //! use std::io::prelude::*; | |
166 | //! | |
167 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 168 | //! io::stdout().write(&[42])?; |
c1a9b12d SL |
169 | //! # Ok(()) |
170 | //! # } | |
171 | //! ``` | |
172 | //! | |
cc61c64b | 173 | //! Of course, using [`io::stdout`] directly is less common than something like |
c30ab7b3 | 174 | //! [`println!`]. |
c1a9b12d SL |
175 | //! |
176 | //! ## Iterator types | |
177 | //! | |
178 | //! A large number of the structures provided by `std::io` are for various | |
c30ab7b3 | 179 | //! ways of iterating over I/O. For example, [`Lines`] is used to split over |
c1a9b12d SL |
180 | //! lines: |
181 | //! | |
182 | //! ``` | |
183 | //! use std::io; | |
184 | //! use std::io::prelude::*; | |
185 | //! use std::io::BufReader; | |
186 | //! use std::fs::File; | |
187 | //! | |
188 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 189 | //! let f = File::open("foo.txt")?; |
a7813a04 | 190 | //! let reader = BufReader::new(f); |
c1a9b12d SL |
191 | //! |
192 | //! for line in reader.lines() { | |
32a655c1 | 193 | //! println!("{}", line?); |
c1a9b12d SL |
194 | //! } |
195 | //! | |
196 | //! # Ok(()) | |
197 | //! # } | |
198 | //! ``` | |
199 | //! | |
200 | //! ## Functions | |
201 | //! | |
a7813a04 | 202 | //! There are a number of [functions][functions-list] that offer access to various |
c1a9b12d SL |
203 | //! features. For example, we can use three of these functions to copy everything |
204 | //! from standard input to standard output: | |
205 | //! | |
206 | //! ``` | |
207 | //! use std::io; | |
208 | //! | |
209 | //! # fn foo() -> io::Result<()> { | |
32a655c1 | 210 | //! io::copy(&mut io::stdin(), &mut io::stdout())?; |
c1a9b12d SL |
211 | //! # Ok(()) |
212 | //! # } | |
213 | //! ``` | |
214 | //! | |
a7813a04 | 215 | //! [functions-list]: #functions-1 |
c1a9b12d SL |
216 | //! |
217 | //! ## io::Result | |
218 | //! | |
c30ab7b3 | 219 | //! Last, but certainly not least, is [`io::Result`]. This type is used |
c1a9b12d SL |
220 | //! as the return type of many `std::io` functions that can cause an error, and |
221 | //! can be returned from your own functions as well. Many of the examples in this | |
32a655c1 | 222 | //! module use the [`?` operator]: |
c1a9b12d SL |
223 | //! |
224 | //! ``` | |
225 | //! use std::io; | |
226 | //! | |
227 | //! fn read_input() -> io::Result<()> { | |
228 | //! let mut input = String::new(); | |
229 | //! | |
32a655c1 | 230 | //! io::stdin().read_line(&mut input)?; |
c1a9b12d SL |
231 | //! |
232 | //! println!("You typed: {}", input.trim()); | |
233 | //! | |
234 | //! Ok(()) | |
235 | //! } | |
236 | //! ``` | |
237 | //! | |
c30ab7b3 SL |
238 | //! The return type of `read_input()`, [`io::Result<()>`][`io::Result`], is a very |
239 | //! common type for functions which don't have a 'real' return value, but do want to | |
240 | //! return errors if they happen. In this case, the only purpose of this function is | |
b039eaaf | 241 | //! to read the line and print it, so we use `()`. |
c1a9b12d | 242 | //! |
9cc50fc6 SL |
243 | //! ## Platform-specific behavior |
244 | //! | |
245 | //! Many I/O functions throughout the standard library are documented to indicate | |
246 | //! what various library or syscalls they are delegated to. This is done to help | |
247 | //! applications both understand what's happening under the hood as well as investigate | |
248 | //! any possibly unclear semantics. Note, however, that this is informative, not a binding | |
249 | //! contract. The implementation of many of these functions are subject to change over | |
250 | //! time and may call fewer or more syscalls/library functions. | |
c30ab7b3 SL |
251 | //! |
252 | //! [`Read`]: trait.Read.html | |
253 | //! [`Write`]: trait.Write.html | |
254 | //! [`Seek`]: trait.Seek.html | |
255 | //! [`BufRead`]: trait.BufRead.html | |
256 | //! [`File`]: ../fs/struct.File.html | |
257 | //! [`TcpStream`]: ../net/struct.TcpStream.html | |
258 | //! [`Vec<T>`]: ../vec/struct.Vec.html | |
259 | //! [`BufReader`]: struct.BufReader.html | |
260 | //! [`BufWriter`]: struct.BufWriter.html | |
cc61c64b XL |
261 | //! [`Write::write`]: trait.Write.html#tymethod.write |
262 | //! [`io::stdout`]: fn.stdout.html | |
c30ab7b3 SL |
263 | //! [`println!`]: ../macro.println.html |
264 | //! [`Lines`]: struct.Lines.html | |
265 | //! [`io::Result`]: type.Result.html | |
041b39d2 | 266 | //! [`?` operator]: ../../book/first-edition/syntax-index.html |
cc61c64b | 267 | //! [`Read::read`]: trait.Read.html#tymethod.read |
3b2f2976 XL |
268 | //! [`Result`]: ../result/enum.Result.html |
269 | //! [`.unwrap()`]: ../result/enum.Result.html#method.unwrap | |
1a4d82fc | 270 | |
c34b1796 | 271 | #![stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 272 | |
85aaf69f | 273 | use cmp; |
8bb4bdeb | 274 | use core::str as core_str; |
c34b1796 | 275 | use error as std_error; |
1a4d82fc | 276 | use fmt; |
85aaf69f | 277 | use result; |
c34b1796 | 278 | use str; |
9cc50fc6 | 279 | use memchr; |
041b39d2 | 280 | use ptr; |
1a4d82fc | 281 | |
92a42be0 | 282 | #[stable(feature = "rust1", since = "1.0.0")] |
e9174d1e | 283 | pub use self::buffered::{BufReader, BufWriter, LineWriter}; |
92a42be0 | 284 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 285 | pub use self::buffered::IntoInnerError; |
92a42be0 | 286 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 287 | pub use self::cursor::Cursor; |
92a42be0 | 288 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 289 | pub use self::error::{Result, Error, ErrorKind}; |
92a42be0 | 290 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 291 | pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat}; |
92a42be0 | 292 | #[stable(feature = "rust1", since = "1.0.0")] |
7cac9316 | 293 | pub use self::stdio::{stdin, stdout, stderr, Stdin, Stdout, Stderr}; |
92a42be0 | 294 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 | 295 | pub use self::stdio::{StdoutLock, StderrLock, StdinLock}; |
7cac9316 XL |
296 | #[unstable(feature = "print_internals", issue = "0")] |
297 | pub use self::stdio::{_print, _eprint}; | |
041b39d2 | 298 | #[unstable(feature = "libstd_io_internals", issue = "42788")] |
c34b1796 AL |
299 | #[doc(no_inline, hidden)] |
300 | pub use self::stdio::{set_panic, set_print}; | |
301 | ||
85aaf69f | 302 | pub mod prelude; |
1a4d82fc | 303 | mod buffered; |
85aaf69f SL |
304 | mod cursor; |
305 | mod error; | |
306 | mod impls; | |
62682a34 | 307 | mod lazy; |
85aaf69f | 308 | mod util; |
c34b1796 | 309 | mod stdio; |
1a4d82fc | 310 | |
c30ab7b3 | 311 | const DEFAULT_BUF_SIZE: usize = ::sys_common::io::DEFAULT_BUF_SIZE; |
1a4d82fc | 312 | |
041b39d2 XL |
313 | struct Guard<'a> { buf: &'a mut Vec<u8>, len: usize } |
314 | ||
315 | impl<'a> Drop for Guard<'a> { | |
316 | fn drop(&mut self) { | |
317 | unsafe { self.buf.set_len(self.len); } | |
318 | } | |
319 | } | |
320 | ||
85aaf69f SL |
321 | // A few methods below (read_to_string, read_line) will append data into a |
322 | // `String` buffer, but we need to be pretty careful when doing this. The | |
323 | // implementation will just call `.as_mut_vec()` and then delegate to a | |
324 | // byte-oriented reading method, but we must ensure that when returning we never | |
325 | // leave `buf` in a state such that it contains invalid UTF-8 in its bounds. | |
326 | // | |
327 | // To this end, we use an RAII guard (to protect against panics) which updates | |
328 | // the length of the string when it is dropped. This guard initially truncates | |
329 | // the string to the prior length and only after we've validated that the | |
330 | // new contents are valid UTF-8 do we allow it to set a longer length. | |
331 | // | |
332 | // The unsafety in this function is twofold: | |
333 | // | |
334 | // 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8 | |
335 | // checks. | |
336 | // 2. We're passing a raw buffer to the function `f`, and it is expected that | |
337 | // the function only *appends* bytes to the buffer. We'll get undefined | |
338 | // behavior if existing bytes are overwritten to have non-UTF-8 data. | |
c34b1796 AL |
339 | fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize> |
340 | where F: FnOnce(&mut Vec<u8>) -> Result<usize> | |
85aaf69f | 341 | { |
85aaf69f | 342 | unsafe { |
041b39d2 XL |
343 | let mut g = Guard { len: buf.len(), buf: buf.as_mut_vec() }; |
344 | let ret = f(g.buf); | |
345 | if str::from_utf8(&g.buf[g.len..]).is_err() { | |
c34b1796 | 346 | ret.and_then(|_| { |
62682a34 | 347 | Err(Error::new(ErrorKind::InvalidData, |
c34b1796 | 348 | "stream did not contain valid UTF-8")) |
85aaf69f SL |
349 | }) |
350 | } else { | |
041b39d2 | 351 | g.len = g.buf.len(); |
85aaf69f SL |
352 | ret |
353 | } | |
1a4d82fc JJ |
354 | } |
355 | } | |
356 | ||
c34b1796 AL |
357 | // This uses an adaptive system to extend the vector when it fills. We want to |
358 | // avoid paying to allocate and zero a huge chunk of memory if the reader only | |
359 | // has 4 bytes while still making large reads if the reader does have a ton | |
360 | // of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every | |
361 | // time is 4,500 times (!) slower than this if the reader has a very small | |
362 | // amount of data to return. | |
041b39d2 XL |
363 | // |
364 | // Because we're extending the buffer with uninitialized data for trusted | |
365 | // readers, we need to make sure to truncate that if any of this panics. | |
c34b1796 AL |
366 | fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> { |
367 | let start_len = buf.len(); | |
041b39d2 | 368 | let mut g = Guard { len: buf.len(), buf: buf }; |
c34b1796 AL |
369 | let mut new_write_size = 16; |
370 | let ret; | |
85aaf69f | 371 | loop { |
041b39d2 | 372 | if g.len == g.buf.len() { |
c34b1796 AL |
373 | if new_write_size < DEFAULT_BUF_SIZE { |
374 | new_write_size *= 2; | |
375 | } | |
041b39d2 XL |
376 | unsafe { |
377 | g.buf.reserve(new_write_size); | |
378 | g.buf.set_len(g.len + new_write_size); | |
379 | r.initializer().initialize(&mut g.buf[g.len..]); | |
380 | } | |
85aaf69f | 381 | } |
c34b1796 | 382 | |
041b39d2 | 383 | match r.read(&mut g.buf[g.len..]) { |
c34b1796 | 384 | Ok(0) => { |
041b39d2 | 385 | ret = Ok(g.len - start_len); |
c34b1796 AL |
386 | break; |
387 | } | |
041b39d2 | 388 | Ok(n) => g.len += n, |
85aaf69f | 389 | Err(ref e) if e.kind() == ErrorKind::Interrupted => {} |
c34b1796 AL |
390 | Err(e) => { |
391 | ret = Err(e); | |
392 | break; | |
393 | } | |
85aaf69f | 394 | } |
1a4d82fc | 395 | } |
c34b1796 | 396 | |
c34b1796 | 397 | ret |
1a4d82fc JJ |
398 | } |
399 | ||
c1a9b12d | 400 | /// The `Read` trait allows for reading bytes from a source. |
85aaf69f | 401 | /// |
041b39d2 | 402 | /// Implementors of the `Read` trait are called 'readers'. |
1a4d82fc | 403 | /// |
3b2f2976 | 404 | /// Readers are defined by one required method, [`read()`]. Each call to [`read()`] |
c1a9b12d | 405 | /// will attempt to pull bytes from this source into a provided buffer. A |
3b2f2976 | 406 | /// number of other methods are implemented in terms of [`read()`], giving |
c1a9b12d SL |
407 | /// implementors a number of ways to read bytes while only needing to implement |
408 | /// a single method. | |
409 | /// | |
410 | /// Readers are intended to be composable with one another. Many implementors | |
3b2f2976 | 411 | /// throughout [`std::io`] take and provide types which implement the `Read` |
c1a9b12d SL |
412 | /// trait. |
413 | /// | |
3b2f2976 XL |
414 | /// Please note that each call to [`read()`] may involve a system call, and |
415 | /// therefore, using something that implements [`BufRead`], such as | |
416 | /// [`BufReader`], will be more efficient. | |
b039eaaf | 417 | /// |
c1a9b12d SL |
418 | /// # Examples |
419 | /// | |
3b2f2976 | 420 | /// [`File`]s implement `Read`: |
c1a9b12d | 421 | /// |
3b2f2976 XL |
422 | /// [`read()`]: trait.Read.html#tymethod.read |
423 | /// [`std::io`]: ../../std/io/index.html | |
424 | /// [`File`]: ../fs/struct.File.html | |
425 | /// [`BufRead`]: trait.BufRead.html | |
426 | /// [`BufReader`]: struct.BufReader.html | |
c1a9b12d SL |
427 | /// |
428 | /// ``` | |
429 | /// use std::io; | |
430 | /// use std::io::prelude::*; | |
431 | /// use std::fs::File; | |
432 | /// | |
433 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 434 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
435 | /// let mut buffer = [0; 10]; |
436 | /// | |
437 | /// // read up to 10 bytes | |
32a655c1 | 438 | /// f.read(&mut buffer)?; |
c1a9b12d SL |
439 | /// |
440 | /// let mut buffer = vec![0; 10]; | |
441 | /// // read the whole file | |
32a655c1 | 442 | /// f.read_to_end(&mut buffer)?; |
c1a9b12d SL |
443 | /// |
444 | /// // read into a String, so that you don't need to do the conversion. | |
445 | /// let mut buffer = String::new(); | |
32a655c1 | 446 | /// f.read_to_string(&mut buffer)?; |
c1a9b12d SL |
447 | /// |
448 | /// // and more! See the other methods for more details. | |
449 | /// # Ok(()) | |
450 | /// # } | |
451 | /// ``` | |
c34b1796 | 452 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
453 | pub trait Read { |
454 | /// Pull some bytes from this source into the specified buffer, returning | |
455 | /// how many bytes were read. | |
456 | /// | |
457 | /// This function does not provide any guarantees about whether it blocks | |
458 | /// waiting for data, but if an object needs to block for a read but cannot | |
3b2f2976 | 459 | /// it will typically signal this via an [`Err`] return value. |
85aaf69f | 460 | /// |
3b2f2976 | 461 | /// If the return value of this method is [`Ok(n)`], then it must be |
85aaf69f | 462 | /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates |
9346a6ac | 463 | /// that the buffer `buf` has been filled in with `n` bytes of data from this |
85aaf69f SL |
464 | /// source. If `n` is `0`, then it can indicate one of two scenarios: |
465 | /// | |
466 | /// 1. This reader has reached its "end of file" and will likely no longer | |
467 | /// be able to produce bytes. Note that this does not mean that the | |
468 | /// reader will *always* no longer be able to produce bytes. | |
469 | /// 2. The buffer specified was 0 bytes in length. | |
470 | /// | |
471 | /// No guarantees are provided about the contents of `buf` when this | |
472 | /// function is called, implementations cannot rely on any property of the | |
473 | /// contents of `buf` being true. It is recommended that implementations | |
474 | /// only write data to `buf` instead of reading its contents. | |
1a4d82fc | 475 | /// |
85aaf69f | 476 | /// # Errors |
1a4d82fc | 477 | /// |
85aaf69f SL |
478 | /// If this function encounters any form of I/O or other error, an error |
479 | /// variant will be returned. If an error is returned then it must be | |
480 | /// guaranteed that no bytes were read. | |
c1a9b12d | 481 | /// |
3b2f2976 | 482 | /// An error of the [`ErrorKind::Interrupted`] kind is non-fatal and the read |
7cac9316 XL |
483 | /// operation should be retried if there is nothing else to do. |
484 | /// | |
c1a9b12d SL |
485 | /// # Examples |
486 | /// | |
3b2f2976 | 487 | /// [`File`]s implement `Read`: |
c1a9b12d | 488 | /// |
3b2f2976 XL |
489 | /// [`Err`]: ../../std/result/enum.Result.html#variant.Err |
490 | /// [`Ok(n)`]: ../../std/result/enum.Result.html#variant.Ok | |
491 | /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted | |
492 | /// [`File`]: ../fs/struct.File.html | |
c1a9b12d SL |
493 | /// |
494 | /// ``` | |
495 | /// use std::io; | |
496 | /// use std::io::prelude::*; | |
497 | /// use std::fs::File; | |
498 | /// | |
499 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 500 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
501 | /// let mut buffer = [0; 10]; |
502 | /// | |
7cac9316 | 503 | /// // read up to 10 bytes |
32a655c1 | 504 | /// f.read(&mut buffer[..])?; |
c1a9b12d SL |
505 | /// # Ok(()) |
506 | /// # } | |
507 | /// ``` | |
c34b1796 | 508 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 509 | fn read(&mut self, buf: &mut [u8]) -> Result<usize>; |
1a4d82fc | 510 | |
041b39d2 XL |
511 | /// Determines if this `Read`er can work with buffers of uninitialized |
512 | /// memory. | |
513 | /// | |
514 | /// The default implementation returns an initializer which will zero | |
515 | /// buffers. | |
516 | /// | |
517 | /// If a `Read`er guarantees that it can work properly with uninitialized | |
3b2f2976 XL |
518 | /// memory, it should call [`Initializer::nop()`]. See the documentation for |
519 | /// [`Initializer`] for details. | |
041b39d2 XL |
520 | /// |
521 | /// The behavior of this method must be independent of the state of the | |
522 | /// `Read`er - the method only takes `&self` so that it can be used through | |
523 | /// trait objects. | |
524 | /// | |
3b2f2976 | 525 | /// # Safety |
041b39d2 XL |
526 | /// |
527 | /// This method is unsafe because a `Read`er could otherwise return a | |
528 | /// non-zeroing `Initializer` from another `Read` type without an `unsafe` | |
529 | /// block. | |
3b2f2976 XL |
530 | /// |
531 | /// [`Initializer::nop()`]: ../../std/io/struct.Initializer.html#method.nop | |
532 | /// [`Initializer`]: ../../std/io/struct.Initializer.html | |
041b39d2 XL |
533 | #[unstable(feature = "read_initializer", issue = "42788")] |
534 | #[inline] | |
535 | unsafe fn initializer(&self) -> Initializer { | |
536 | Initializer::zeroing() | |
537 | } | |
538 | ||
85aaf69f | 539 | /// Read all bytes until EOF in this source, placing them into `buf`. |
1a4d82fc | 540 | /// |
85aaf69f | 541 | /// All bytes read from this source will be appended to the specified buffer |
3b2f2976 XL |
542 | /// `buf`. This function will continuously call [`read()`] to append more data to |
543 | /// `buf` until [`read()`] returns either [`Ok(0)`] or an error of | |
544 | /// non-[`ErrorKind::Interrupted`] kind. | |
1a4d82fc | 545 | /// |
9346a6ac | 546 | /// If successful, this function will return the total number of bytes read. |
1a4d82fc | 547 | /// |
85aaf69f | 548 | /// # Errors |
1a4d82fc | 549 | /// |
85aaf69f | 550 | /// If this function encounters an error of the kind |
3b2f2976 | 551 | /// [`ErrorKind::Interrupted`] then the error is ignored and the operation |
85aaf69f | 552 | /// will continue. |
1a4d82fc | 553 | /// |
85aaf69f SL |
554 | /// If any other read error is encountered then this function immediately |
555 | /// returns. Any bytes which have already been read will be appended to | |
556 | /// `buf`. | |
c1a9b12d SL |
557 | /// |
558 | /// # Examples | |
559 | /// | |
3b2f2976 | 560 | /// [`File`]s implement `Read`: |
c1a9b12d | 561 | /// |
3b2f2976 XL |
562 | /// [`read()`]: trait.Read.html#tymethod.read |
563 | /// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok | |
564 | /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted | |
565 | /// [`File`]: ../fs/struct.File.html | |
c1a9b12d SL |
566 | /// |
567 | /// ``` | |
568 | /// use std::io; | |
569 | /// use std::io::prelude::*; | |
570 | /// use std::fs::File; | |
571 | /// | |
572 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 573 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
574 | /// let mut buffer = Vec::new(); |
575 | /// | |
576 | /// // read the whole file | |
32a655c1 | 577 | /// f.read_to_end(&mut buffer)?; |
c1a9b12d SL |
578 | /// # Ok(()) |
579 | /// # } | |
580 | /// ``` | |
c34b1796 AL |
581 | #[stable(feature = "rust1", since = "1.0.0")] |
582 | fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> { | |
85aaf69f | 583 | read_to_end(self, buf) |
1a4d82fc JJ |
584 | } |
585 | ||
85aaf69f | 586 | /// Read all bytes until EOF in this source, placing them into `buf`. |
1a4d82fc | 587 | /// |
c34b1796 AL |
588 | /// If successful, this function returns the number of bytes which were read |
589 | /// and appended to `buf`. | |
590 | /// | |
85aaf69f | 591 | /// # Errors |
1a4d82fc | 592 | /// |
85aaf69f SL |
593 | /// If the data in this stream is *not* valid UTF-8 then an error is |
594 | /// returned and `buf` is unchanged. | |
1a4d82fc | 595 | /// |
cc61c64b | 596 | /// See [`read_to_end`][readtoend] for other error semantics. |
c1a9b12d SL |
597 | /// |
598 | /// [readtoend]: #method.read_to_end | |
599 | /// | |
600 | /// # Examples | |
601 | /// | |
602 | /// [`File`][file]s implement `Read`: | |
603 | /// | |
9cc50fc6 | 604 | /// [file]: ../fs/struct.File.html |
c1a9b12d SL |
605 | /// |
606 | /// ``` | |
607 | /// use std::io; | |
608 | /// use std::io::prelude::*; | |
609 | /// use std::fs::File; | |
610 | /// | |
611 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 612 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
613 | /// let mut buffer = String::new(); |
614 | /// | |
32a655c1 | 615 | /// f.read_to_string(&mut buffer)?; |
c1a9b12d SL |
616 | /// # Ok(()) |
617 | /// # } | |
618 | /// ``` | |
c34b1796 AL |
619 | #[stable(feature = "rust1", since = "1.0.0")] |
620 | fn read_to_string(&mut self, buf: &mut String) -> Result<usize> { | |
85aaf69f SL |
621 | // Note that we do *not* call `.read_to_end()` here. We are passing |
622 | // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end` | |
623 | // method to fill it up. An arbitrary implementation could overwrite the | |
624 | // entire contents of the vector, not just append to it (which is what | |
625 | // we are expecting). | |
626 | // | |
627 | // To prevent extraneously checking the UTF-8-ness of the entire buffer | |
628 | // we pass it to our hardcoded `read_to_end` implementation which we | |
629 | // know is guaranteed to only read data into the end of the buffer. | |
630 | append_to_string(buf, |b| read_to_end(self, b)) | |
1a4d82fc JJ |
631 | } |
632 | ||
e9174d1e SL |
633 | /// Read the exact number of bytes required to fill `buf`. |
634 | /// | |
635 | /// This function reads as many bytes as necessary to completely fill the | |
636 | /// specified buffer `buf`. | |
637 | /// | |
638 | /// No guarantees are provided about the contents of `buf` when this | |
639 | /// function is called, implementations cannot rely on any property of the | |
640 | /// contents of `buf` being true. It is recommended that implementations | |
641 | /// only write data to `buf` instead of reading its contents. | |
642 | /// | |
643 | /// # Errors | |
644 | /// | |
645 | /// If this function encounters an error of the kind | |
3b2f2976 | 646 | /// [`ErrorKind::Interrupted`] then the error is ignored and the operation |
e9174d1e SL |
647 | /// will continue. |
648 | /// | |
649 | /// If this function encounters an "end of file" before completely filling | |
3b2f2976 | 650 | /// the buffer, it returns an error of the kind [`ErrorKind::UnexpectedEof`]. |
e9174d1e SL |
651 | /// The contents of `buf` are unspecified in this case. |
652 | /// | |
653 | /// If any other read error is encountered then this function immediately | |
654 | /// returns. The contents of `buf` are unspecified in this case. | |
655 | /// | |
656 | /// If this function returns an error, it is unspecified how many bytes it | |
657 | /// has read, but it will never read more than would be necessary to | |
658 | /// completely fill the buffer. | |
659 | /// | |
660 | /// # Examples | |
661 | /// | |
3b2f2976 | 662 | /// [`File`]s implement `Read`: |
e9174d1e | 663 | /// |
3b2f2976 XL |
664 | /// [`File`]: ../fs/struct.File.html |
665 | /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted | |
666 | /// [`ErrorKind::UnexpectedEof`]: ../../std/io/enum.ErrorKind.html#variant.UnexpectedEof | |
e9174d1e SL |
667 | /// |
668 | /// ``` | |
e9174d1e SL |
669 | /// use std::io; |
670 | /// use std::io::prelude::*; | |
671 | /// use std::fs::File; | |
672 | /// | |
673 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 674 | /// let mut f = File::open("foo.txt")?; |
e9174d1e SL |
675 | /// let mut buffer = [0; 10]; |
676 | /// | |
677 | /// // read exactly 10 bytes | |
32a655c1 | 678 | /// f.read_exact(&mut buffer)?; |
e9174d1e SL |
679 | /// # Ok(()) |
680 | /// # } | |
681 | /// ``` | |
92a42be0 | 682 | #[stable(feature = "read_exact", since = "1.6.0")] |
e9174d1e SL |
683 | fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> { |
684 | while !buf.is_empty() { | |
685 | match self.read(buf) { | |
686 | Ok(0) => break, | |
687 | Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; } | |
688 | Err(ref e) if e.kind() == ErrorKind::Interrupted => {} | |
689 | Err(e) => return Err(e), | |
690 | } | |
691 | } | |
692 | if !buf.is_empty() { | |
92a42be0 | 693 | Err(Error::new(ErrorKind::UnexpectedEof, |
e9174d1e SL |
694 | "failed to fill whole buffer")) |
695 | } else { | |
696 | Ok(()) | |
697 | } | |
698 | } | |
699 | ||
9346a6ac | 700 | /// Creates a "by reference" adaptor for this instance of `Read`. |
1a4d82fc | 701 | /// |
85aaf69f SL |
702 | /// The returned adaptor also implements `Read` and will simply borrow this |
703 | /// current reader. | |
c1a9b12d SL |
704 | /// |
705 | /// # Examples | |
706 | /// | |
707 | /// [`File`][file]s implement `Read`: | |
708 | /// | |
9cc50fc6 | 709 | /// [file]: ../fs/struct.File.html |
c1a9b12d SL |
710 | /// |
711 | /// ``` | |
712 | /// use std::io; | |
713 | /// use std::io::Read; | |
714 | /// use std::fs::File; | |
715 | /// | |
716 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 717 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
718 | /// let mut buffer = Vec::new(); |
719 | /// let mut other_buffer = Vec::new(); | |
720 | /// | |
721 | /// { | |
722 | /// let reference = f.by_ref(); | |
723 | /// | |
724 | /// // read at most 5 bytes | |
32a655c1 | 725 | /// reference.take(5).read_to_end(&mut buffer)?; |
c1a9b12d SL |
726 | /// |
727 | /// } // drop our &mut reference so we can use f again | |
728 | /// | |
729 | /// // original file still usable, read the rest | |
32a655c1 | 730 | /// f.read_to_end(&mut other_buffer)?; |
c1a9b12d SL |
731 | /// # Ok(()) |
732 | /// # } | |
733 | /// ``` | |
c34b1796 AL |
734 | #[stable(feature = "rust1", since = "1.0.0")] |
735 | fn by_ref(&mut self) -> &mut Self where Self: Sized { self } | |
1a4d82fc | 736 | |
3b2f2976 | 737 | /// Transforms this `Read` instance to an [`Iterator`] over its bytes. |
1a4d82fc | 738 | /// |
3b2f2976 XL |
739 | /// The returned type implements [`Iterator`] where the `Item` is [`Result`]`<`[`u8`]`, |
740 | /// R::Err>`. The yielded item is [`Ok`] if a byte was successfully read and | |
741 | /// [`Err`] otherwise for I/O errors. EOF is mapped to returning [`None`] from | |
85aaf69f | 742 | /// this iterator. |
c1a9b12d SL |
743 | /// |
744 | /// # Examples | |
745 | /// | |
746 | /// [`File`][file]s implement `Read`: | |
747 | /// | |
9cc50fc6 | 748 | /// [file]: ../fs/struct.File.html |
3b2f2976 XL |
749 | /// [`Iterator`]: ../../std/iter/trait.Iterator.html |
750 | /// [`Result`]: ../../std/result/enum.Result.html | |
751 | /// [`u8`]: ../../std/primitive.u8.html | |
752 | /// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok | |
753 | /// [`Err`]: ../../std/result/enum.Result.html#variant.Err | |
754 | /// [`None`]: ../../std/option/enum.Option.html#variant.None | |
c1a9b12d SL |
755 | /// |
756 | /// ``` | |
757 | /// use std::io; | |
758 | /// use std::io::prelude::*; | |
759 | /// use std::fs::File; | |
760 | /// | |
761 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 762 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
763 | /// |
764 | /// for byte in f.bytes() { | |
765 | /// println!("{}", byte.unwrap()); | |
766 | /// } | |
767 | /// # Ok(()) | |
768 | /// # } | |
769 | /// ``` | |
c34b1796 AL |
770 | #[stable(feature = "rust1", since = "1.0.0")] |
771 | fn bytes(self) -> Bytes<Self> where Self: Sized { | |
85aaf69f | 772 | Bytes { inner: self } |
1a4d82fc JJ |
773 | } |
774 | ||
3b2f2976 | 775 | /// Transforms this `Read` instance to an [`Iterator`] over [`char`]s. |
1a4d82fc | 776 | /// |
d9579d0f | 777 | /// This adaptor will attempt to interpret this reader as a UTF-8 encoded |
3b2f2976 | 778 | /// sequence of characters. The returned iterator will return [`None`] once |
85aaf69f | 779 | /// EOF is reached for this reader. Otherwise each element yielded will be a |
3b2f2976 | 780 | /// [`Result`]`<`[`char`]`, E>` where `E` may contain information about what I/O error |
85aaf69f | 781 | /// occurred or where decoding failed. |
1a4d82fc | 782 | /// |
85aaf69f SL |
783 | /// Currently this adaptor will discard intermediate data read, and should |
784 | /// be avoided if this is not desired. | |
c1a9b12d SL |
785 | /// |
786 | /// # Examples | |
787 | /// | |
3b2f2976 | 788 | /// [`File`]s implement `Read`: |
c1a9b12d | 789 | /// |
3b2f2976 XL |
790 | /// [`File`]: ../fs/struct.File.html |
791 | /// [`Iterator`]: ../../std/iter/trait.Iterator.html | |
792 | /// [`Result`]: ../../std/result/enum.Result.html | |
793 | /// [`char`]: ../../std/primitive.char.html | |
794 | /// [`None`]: ../../std/option/enum.Option.html#variant.None | |
c1a9b12d SL |
795 | /// |
796 | /// ``` | |
797 | /// #![feature(io)] | |
798 | /// use std::io; | |
799 | /// use std::io::prelude::*; | |
800 | /// use std::fs::File; | |
801 | /// | |
802 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 803 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
804 | /// |
805 | /// for c in f.chars() { | |
806 | /// println!("{}", c.unwrap()); | |
807 | /// } | |
808 | /// # Ok(()) | |
809 | /// # } | |
810 | /// ``` | |
c34b1796 AL |
811 | #[unstable(feature = "io", reason = "the semantics of a partial read/write \ |
812 | of where errors happen is currently \ | |
e9174d1e SL |
813 | unclear and may change", |
814 | issue = "27802")] | |
c34b1796 | 815 | fn chars(self) -> Chars<Self> where Self: Sized { |
85aaf69f | 816 | Chars { inner: self } |
1a4d82fc JJ |
817 | } |
818 | ||
9346a6ac | 819 | /// Creates an adaptor which will chain this stream with another. |
1a4d82fc | 820 | /// |
85aaf69f SL |
821 | /// The returned `Read` instance will first read all bytes from this object |
822 | /// until EOF is encountered. Afterwards the output is equivalent to the | |
823 | /// output of `next`. | |
c1a9b12d SL |
824 | /// |
825 | /// # Examples | |
826 | /// | |
827 | /// [`File`][file]s implement `Read`: | |
828 | /// | |
9cc50fc6 | 829 | /// [file]: ../fs/struct.File.html |
c1a9b12d SL |
830 | /// |
831 | /// ``` | |
832 | /// use std::io; | |
833 | /// use std::io::prelude::*; | |
834 | /// use std::fs::File; | |
835 | /// | |
836 | /// # fn foo() -> io::Result<()> { | |
32a655c1 SL |
837 | /// let mut f1 = File::open("foo.txt")?; |
838 | /// let mut f2 = File::open("bar.txt")?; | |
c1a9b12d SL |
839 | /// |
840 | /// let mut handle = f1.chain(f2); | |
841 | /// let mut buffer = String::new(); | |
842 | /// | |
843 | /// // read the value into a String. We could use any Read method here, | |
844 | /// // this is just one example. | |
32a655c1 | 845 | /// handle.read_to_string(&mut buffer)?; |
c1a9b12d SL |
846 | /// # Ok(()) |
847 | /// # } | |
848 | /// ``` | |
c34b1796 AL |
849 | #[stable(feature = "rust1", since = "1.0.0")] |
850 | fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized { | |
85aaf69f | 851 | Chain { first: self, second: next, done_first: false } |
1a4d82fc JJ |
852 | } |
853 | ||
9346a6ac | 854 | /// Creates an adaptor which will read at most `limit` bytes from it. |
1a4d82fc | 855 | /// |
85aaf69f | 856 | /// This function returns a new instance of `Read` which will read at most |
3b2f2976 | 857 | /// `limit` bytes, after which it will always return EOF ([`Ok(0)`]). Any |
85aaf69f | 858 | /// read errors will not count towards the number of bytes read and future |
3b2f2976 | 859 | /// calls to [`read()`] may succeed. |
c1a9b12d SL |
860 | /// |
861 | /// # Examples | |
862 | /// | |
3b2f2976 | 863 | /// [`File`]s implement `Read`: |
c1a9b12d | 864 | /// |
3b2f2976 XL |
865 | /// [`File`]: ../fs/struct.File.html |
866 | /// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok | |
867 | /// [`read()`]: trait.Read.html#tymethod.read | |
c1a9b12d SL |
868 | /// |
869 | /// ``` | |
870 | /// use std::io; | |
871 | /// use std::io::prelude::*; | |
872 | /// use std::fs::File; | |
873 | /// | |
874 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 875 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
876 | /// let mut buffer = [0; 5]; |
877 | /// | |
878 | /// // read at most five bytes | |
879 | /// let mut handle = f.take(5); | |
880 | /// | |
32a655c1 | 881 | /// handle.read(&mut buffer)?; |
c1a9b12d SL |
882 | /// # Ok(()) |
883 | /// # } | |
884 | /// ``` | |
c34b1796 AL |
885 | #[stable(feature = "rust1", since = "1.0.0")] |
886 | fn take(self, limit: u64) -> Take<Self> where Self: Sized { | |
85aaf69f | 887 | Take { inner: self, limit: limit } |
1a4d82fc | 888 | } |
85aaf69f | 889 | } |
1a4d82fc | 890 | |
041b39d2 XL |
891 | /// A type used to conditionally initialize buffers passed to `Read` methods. |
892 | #[unstable(feature = "read_initializer", issue = "42788")] | |
893 | #[derive(Debug)] | |
894 | pub struct Initializer(bool); | |
895 | ||
896 | impl Initializer { | |
897 | /// Returns a new `Initializer` which will zero out buffers. | |
898 | #[unstable(feature = "read_initializer", issue = "42788")] | |
899 | #[inline] | |
900 | pub fn zeroing() -> Initializer { | |
901 | Initializer(true) | |
902 | } | |
903 | ||
904 | /// Returns a new `Initializer` which will not zero out buffers. | |
905 | /// | |
3b2f2976 | 906 | /// # Safety |
041b39d2 XL |
907 | /// |
908 | /// This may only be called by `Read`ers which guarantee that they will not | |
909 | /// read from buffers passed to `Read` methods, and that the return value of | |
910 | /// the method accurately reflects the number of bytes that have been | |
911 | /// written to the head of the buffer. | |
912 | #[unstable(feature = "read_initializer", issue = "42788")] | |
913 | #[inline] | |
914 | pub unsafe fn nop() -> Initializer { | |
915 | Initializer(false) | |
916 | } | |
917 | ||
918 | /// Indicates if a buffer should be initialized. | |
919 | #[unstable(feature = "read_initializer", issue = "42788")] | |
920 | #[inline] | |
921 | pub fn should_initialize(&self) -> bool { | |
922 | self.0 | |
923 | } | |
924 | ||
925 | /// Initializes a buffer if necessary. | |
926 | #[unstable(feature = "read_initializer", issue = "42788")] | |
927 | #[inline] | |
928 | pub fn initialize(&self, buf: &mut [u8]) { | |
929 | if self.should_initialize() { | |
930 | unsafe { ptr::write_bytes(buf.as_mut_ptr(), 0, buf.len()) } | |
931 | } | |
932 | } | |
933 | } | |
934 | ||
85aaf69f SL |
935 | /// A trait for objects which are byte-oriented sinks. |
936 | /// | |
c1a9b12d SL |
937 | /// Implementors of the `Write` trait are sometimes called 'writers'. |
938 | /// | |
cc61c64b | 939 | /// Writers are defined by two required methods, [`write`] and [`flush`]: |
c1a9b12d | 940 | /// |
cc61c64b | 941 | /// * The [`write`] method will attempt to write some data into the object, |
c1a9b12d SL |
942 | /// returning how many bytes were successfully written. |
943 | /// | |
cc61c64b | 944 | /// * The [`flush`] method is useful for adaptors and explicit buffers |
c1a9b12d SL |
945 | /// themselves for ensuring that all buffered data has been pushed out to the |
946 | /// 'true sink'. | |
947 | /// | |
948 | /// Writers are intended to be composable with one another. Many implementors | |
476ff2be | 949 | /// throughout [`std::io`] take and provide types which implement the `Write` |
c1a9b12d SL |
950 | /// trait. |
951 | /// | |
cc61c64b XL |
952 | /// [`write`]: #tymethod.write |
953 | /// [`flush`]: #tymethod.flush | |
476ff2be SL |
954 | /// [`std::io`]: index.html |
955 | /// | |
c1a9b12d SL |
956 | /// # Examples |
957 | /// | |
958 | /// ``` | |
959 | /// use std::io::prelude::*; | |
960 | /// use std::fs::File; | |
85aaf69f | 961 | /// |
c1a9b12d | 962 | /// # fn foo() -> std::io::Result<()> { |
32a655c1 | 963 | /// let mut buffer = File::create("foo.txt")?; |
85aaf69f | 964 | /// |
32a655c1 | 965 | /// buffer.write(b"some bytes")?; |
c1a9b12d SL |
966 | /// # Ok(()) |
967 | /// # } | |
968 | /// ``` | |
c34b1796 | 969 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
970 | pub trait Write { |
971 | /// Write a buffer into this object, returning how many bytes were written. | |
1a4d82fc | 972 | /// |
85aaf69f SL |
973 | /// This function will attempt to write the entire contents of `buf`, but |
974 | /// the entire write may not succeed, or the write may also generate an | |
975 | /// error. A call to `write` represents *at most one* attempt to write to | |
976 | /// any wrapped object. | |
1a4d82fc | 977 | /// |
85aaf69f | 978 | /// Calls to `write` are not guaranteed to block waiting for data to be |
62682a34 | 979 | /// written, and a write which would otherwise block can be indicated through |
85aaf69f | 980 | /// an `Err` variant. |
1a4d82fc | 981 | /// |
85aaf69f SL |
982 | /// If the return value is `Ok(n)` then it must be guaranteed that |
983 | /// `0 <= n <= buf.len()`. A return value of `0` typically means that the | |
984 | /// underlying object is no longer able to accept bytes and will likely not | |
985 | /// be able to in the future as well, or that the buffer provided is empty. | |
1a4d82fc | 986 | /// |
85aaf69f | 987 | /// # Errors |
1a4d82fc | 988 | /// |
85aaf69f SL |
989 | /// Each call to `write` may generate an I/O error indicating that the |
990 | /// operation could not be completed. If an error is returned then no bytes | |
991 | /// in the buffer were written to this writer. | |
1a4d82fc | 992 | /// |
85aaf69f SL |
993 | /// It is **not** considered an error if the entire buffer could not be |
994 | /// written to this writer. | |
c1a9b12d | 995 | /// |
7cac9316 XL |
996 | /// An error of the `ErrorKind::Interrupted` kind is non-fatal and the |
997 | /// write operation should be retried if there is nothing else to do. | |
998 | /// | |
c1a9b12d SL |
999 | /// # Examples |
1000 | /// | |
1001 | /// ``` | |
1002 | /// use std::io::prelude::*; | |
1003 | /// use std::fs::File; | |
1004 | /// | |
1005 | /// # fn foo() -> std::io::Result<()> { | |
32a655c1 | 1006 | /// let mut buffer = File::create("foo.txt")?; |
c1a9b12d | 1007 | /// |
7cac9316 | 1008 | /// // Writes some prefix of the byte string, not necessarily all of it. |
32a655c1 | 1009 | /// buffer.write(b"some bytes")?; |
c1a9b12d SL |
1010 | /// # Ok(()) |
1011 | /// # } | |
1012 | /// ``` | |
c34b1796 | 1013 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1014 | fn write(&mut self, buf: &[u8]) -> Result<usize>; |
1a4d82fc | 1015 | |
85aaf69f SL |
1016 | /// Flush this output stream, ensuring that all intermediately buffered |
1017 | /// contents reach their destination. | |
1a4d82fc | 1018 | /// |
85aaf69f | 1019 | /// # Errors |
1a4d82fc | 1020 | /// |
85aaf69f SL |
1021 | /// It is considered an error if not all bytes could be written due to |
1022 | /// I/O errors or EOF being reached. | |
c1a9b12d SL |
1023 | /// |
1024 | /// # Examples | |
1025 | /// | |
1026 | /// ``` | |
1027 | /// use std::io::prelude::*; | |
1028 | /// use std::io::BufWriter; | |
1029 | /// use std::fs::File; | |
1030 | /// | |
1031 | /// # fn foo() -> std::io::Result<()> { | |
32a655c1 | 1032 | /// let mut buffer = BufWriter::new(File::create("foo.txt")?); |
c1a9b12d | 1033 | /// |
32a655c1 SL |
1034 | /// buffer.write(b"some bytes")?; |
1035 | /// buffer.flush()?; | |
c1a9b12d SL |
1036 | /// # Ok(()) |
1037 | /// # } | |
1038 | /// ``` | |
c34b1796 | 1039 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1040 | fn flush(&mut self) -> Result<()>; |
1a4d82fc | 1041 | |
85aaf69f | 1042 | /// Attempts to write an entire buffer into this write. |
1a4d82fc | 1043 | /// |
7cac9316 XL |
1044 | /// This method will continuously call `write` until there is no more data |
1045 | /// to be written or an error of non-`ErrorKind::Interrupted` kind is | |
1046 | /// returned. This method will not return until the entire buffer has been | |
1047 | /// successfully written or such an error occurs. The first error that is | |
1048 | /// not of `ErrorKind::Interrupted` kind generated from this method will be | |
1049 | /// returned. | |
1a4d82fc JJ |
1050 | /// |
1051 | /// # Errors | |
1052 | /// | |
7cac9316 XL |
1053 | /// This function will return the first error of |
1054 | /// non-`ErrorKind::Interrupted` kind that `write` returns. | |
c1a9b12d SL |
1055 | /// |
1056 | /// # Examples | |
1057 | /// | |
1058 | /// ``` | |
1059 | /// use std::io::prelude::*; | |
1060 | /// use std::fs::File; | |
1061 | /// | |
1062 | /// # fn foo() -> std::io::Result<()> { | |
32a655c1 | 1063 | /// let mut buffer = File::create("foo.txt")?; |
c1a9b12d | 1064 | /// |
32a655c1 | 1065 | /// buffer.write_all(b"some bytes")?; |
c1a9b12d SL |
1066 | /// # Ok(()) |
1067 | /// # } | |
1068 | /// ``` | |
c34b1796 | 1069 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1070 | fn write_all(&mut self, mut buf: &[u8]) -> Result<()> { |
9346a6ac | 1071 | while !buf.is_empty() { |
85aaf69f SL |
1072 | match self.write(buf) { |
1073 | Ok(0) => return Err(Error::new(ErrorKind::WriteZero, | |
c34b1796 | 1074 | "failed to write whole buffer")), |
85aaf69f SL |
1075 | Ok(n) => buf = &buf[n..], |
1076 | Err(ref e) if e.kind() == ErrorKind::Interrupted => {} | |
1077 | Err(e) => return Err(e), | |
1078 | } | |
1079 | } | |
1080 | Ok(()) | |
1081 | } | |
1a4d82fc JJ |
1082 | |
1083 | /// Writes a formatted string into this writer, returning any error | |
1084 | /// encountered. | |
1085 | /// | |
c1a9b12d SL |
1086 | /// This method is primarily used to interface with the |
1087 | /// [`format_args!`][formatargs] macro, but it is rare that this should | |
1088 | /// explicitly be called. The [`write!`][write] macro should be favored to | |
1089 | /// invoke this method instead. | |
1090 | /// | |
9e0c209e SL |
1091 | /// [formatargs]: ../macro.format_args.html |
1092 | /// [write]: ../macro.write.html | |
1a4d82fc | 1093 | /// |
c1a9b12d SL |
1094 | /// This function internally uses the [`write_all`][writeall] method on |
1095 | /// this trait and hence will continuously write data so long as no errors | |
1096 | /// are received. This also means that partial writes are not indicated in | |
1097 | /// this signature. | |
1098 | /// | |
1099 | /// [writeall]: #method.write_all | |
85aaf69f | 1100 | /// |
1a4d82fc JJ |
1101 | /// # Errors |
1102 | /// | |
1103 | /// This function will return any I/O error reported while formatting. | |
c1a9b12d SL |
1104 | /// |
1105 | /// # Examples | |
1106 | /// | |
1107 | /// ``` | |
1108 | /// use std::io::prelude::*; | |
1109 | /// use std::fs::File; | |
1110 | /// | |
1111 | /// # fn foo() -> std::io::Result<()> { | |
32a655c1 | 1112 | /// let mut buffer = File::create("foo.txt")?; |
c1a9b12d SL |
1113 | /// |
1114 | /// // this call | |
32a655c1 | 1115 | /// write!(buffer, "{:.*}", 2, 1.234567)?; |
c1a9b12d | 1116 | /// // turns into this: |
32a655c1 | 1117 | /// buffer.write_fmt(format_args!("{:.*}", 2, 1.234567))?; |
c1a9b12d SL |
1118 | /// # Ok(()) |
1119 | /// # } | |
1120 | /// ``` | |
c34b1796 | 1121 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
1122 | fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> { |
1123 | // Create a shim which translates a Write to a fmt::Write and saves | |
1a4d82fc | 1124 | // off I/O errors. instead of discarding them |
85aaf69f | 1125 | struct Adaptor<'a, T: ?Sized + 'a> { |
1a4d82fc | 1126 | inner: &'a mut T, |
85aaf69f | 1127 | error: Result<()>, |
1a4d82fc JJ |
1128 | } |
1129 | ||
85aaf69f | 1130 | impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> { |
1a4d82fc | 1131 | fn write_str(&mut self, s: &str) -> fmt::Result { |
85aaf69f | 1132 | match self.inner.write_all(s.as_bytes()) { |
1a4d82fc JJ |
1133 | Ok(()) => Ok(()), |
1134 | Err(e) => { | |
1135 | self.error = Err(e); | |
1136 | Err(fmt::Error) | |
1137 | } | |
1138 | } | |
1139 | } | |
1140 | } | |
1141 | ||
1142 | let mut output = Adaptor { inner: self, error: Ok(()) }; | |
1143 | match fmt::write(&mut output, fmt) { | |
1144 | Ok(()) => Ok(()), | |
7453a54e SL |
1145 | Err(..) => { |
1146 | // check if the error came from the underlying `Write` or not | |
1147 | if output.error.is_err() { | |
1148 | output.error | |
1149 | } else { | |
1150 | Err(Error::new(ErrorKind::Other, "formatter error")) | |
1151 | } | |
1152 | } | |
1a4d82fc JJ |
1153 | } |
1154 | } | |
1a4d82fc | 1155 | |
9346a6ac | 1156 | /// Creates a "by reference" adaptor for this instance of `Write`. |
1a4d82fc | 1157 | /// |
85aaf69f SL |
1158 | /// The returned adaptor also implements `Write` and will simply borrow this |
1159 | /// current writer. | |
c1a9b12d SL |
1160 | /// |
1161 | /// # Examples | |
1162 | /// | |
1163 | /// ``` | |
1164 | /// use std::io::Write; | |
1165 | /// use std::fs::File; | |
1166 | /// | |
1167 | /// # fn foo() -> std::io::Result<()> { | |
32a655c1 | 1168 | /// let mut buffer = File::create("foo.txt")?; |
c1a9b12d SL |
1169 | /// |
1170 | /// let reference = buffer.by_ref(); | |
1171 | /// | |
1172 | /// // we can use reference just like our original buffer | |
32a655c1 | 1173 | /// reference.write_all(b"some bytes")?; |
c1a9b12d SL |
1174 | /// # Ok(()) |
1175 | /// # } | |
1176 | /// ``` | |
c34b1796 AL |
1177 | #[stable(feature = "rust1", since = "1.0.0")] |
1178 | fn by_ref(&mut self) -> &mut Self where Self: Sized { self } | |
1a4d82fc JJ |
1179 | } |
1180 | ||
c1a9b12d SL |
1181 | /// The `Seek` trait provides a cursor which can be moved within a stream of |
1182 | /// bytes. | |
1a4d82fc | 1183 | /// |
85aaf69f SL |
1184 | /// The stream typically has a fixed size, allowing seeking relative to either |
1185 | /// end or the current offset. | |
c1a9b12d SL |
1186 | /// |
1187 | /// # Examples | |
1188 | /// | |
1189 | /// [`File`][file]s implement `Seek`: | |
1190 | /// | |
9cc50fc6 | 1191 | /// [file]: ../fs/struct.File.html |
c1a9b12d SL |
1192 | /// |
1193 | /// ``` | |
1194 | /// use std::io; | |
1195 | /// use std::io::prelude::*; | |
1196 | /// use std::fs::File; | |
1197 | /// use std::io::SeekFrom; | |
1198 | /// | |
1199 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 1200 | /// let mut f = File::open("foo.txt")?; |
c1a9b12d SL |
1201 | /// |
1202 | /// // move the cursor 42 bytes from the start of the file | |
32a655c1 | 1203 | /// f.seek(SeekFrom::Start(42))?; |
c1a9b12d SL |
1204 | /// # Ok(()) |
1205 | /// # } | |
1206 | /// ``` | |
c34b1796 | 1207 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1208 | pub trait Seek { |
c1a9b12d | 1209 | /// Seek to an offset, in bytes, in a stream. |
85aaf69f | 1210 | /// |
c1a9b12d SL |
1211 | /// A seek beyond the end of a stream is allowed, but implementation |
1212 | /// defined. | |
85aaf69f | 1213 | /// |
c1a9b12d SL |
1214 | /// If the seek operation completed successfully, |
1215 | /// this method returns the new position from the start of the stream. | |
5bcae85e | 1216 | /// That position can be used later with [`SeekFrom::Start`]. |
85aaf69f SL |
1217 | /// |
1218 | /// # Errors | |
1219 | /// | |
c1a9b12d | 1220 | /// Seeking to a negative offset is considered an error. |
5bcae85e SL |
1221 | /// |
1222 | /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start | |
c34b1796 | 1223 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1224 | fn seek(&mut self, pos: SeekFrom) -> Result<u64>; |
1a4d82fc JJ |
1225 | } |
1226 | ||
85aaf69f | 1227 | /// Enumeration of possible methods to seek within an I/O object. |
5bcae85e SL |
1228 | /// |
1229 | /// It is used by the [`Seek`] trait. | |
1230 | /// | |
1231 | /// [`Seek`]: trait.Seek.html | |
85aaf69f | 1232 | #[derive(Copy, PartialEq, Eq, Clone, Debug)] |
c34b1796 | 1233 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
1234 | pub enum SeekFrom { |
1235 | /// Set the offset to the provided number of bytes. | |
c34b1796 | 1236 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1237 | Start(#[stable(feature = "rust1", since = "1.0.0")] u64), |
1a4d82fc | 1238 | |
85aaf69f SL |
1239 | /// Set the offset to the size of this object plus the specified number of |
1240 | /// bytes. | |
1241 | /// | |
9cc50fc6 | 1242 | /// It is possible to seek beyond the end of an object, but it's an error to |
85aaf69f | 1243 | /// seek before byte 0. |
c34b1796 | 1244 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1245 | End(#[stable(feature = "rust1", since = "1.0.0")] i64), |
1a4d82fc | 1246 | |
85aaf69f SL |
1247 | /// Set the offset to the current position plus the specified number of |
1248 | /// bytes. | |
1249 | /// | |
9cc50fc6 | 1250 | /// It is possible to seek beyond the end of an object, but it's an error to |
85aaf69f | 1251 | /// seek before byte 0. |
c34b1796 | 1252 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1253 | Current(#[stable(feature = "rust1", since = "1.0.0")] i64), |
1a4d82fc JJ |
1254 | } |
1255 | ||
85aaf69f | 1256 | fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>) |
c34b1796 AL |
1257 | -> Result<usize> { |
1258 | let mut read = 0; | |
85aaf69f SL |
1259 | loop { |
1260 | let (done, used) = { | |
1261 | let available = match r.fill_buf() { | |
1262 | Ok(n) => n, | |
1263 | Err(ref e) if e.kind() == ErrorKind::Interrupted => continue, | |
1264 | Err(e) => return Err(e) | |
1265 | }; | |
9cc50fc6 | 1266 | match memchr::memchr(delim, available) { |
85aaf69f | 1267 | Some(i) => { |
92a42be0 | 1268 | buf.extend_from_slice(&available[..i + 1]); |
85aaf69f SL |
1269 | (true, i + 1) |
1270 | } | |
1271 | None => { | |
92a42be0 | 1272 | buf.extend_from_slice(available); |
85aaf69f SL |
1273 | (false, available.len()) |
1274 | } | |
1275 | } | |
1276 | }; | |
1277 | r.consume(used); | |
c34b1796 | 1278 | read += used; |
85aaf69f | 1279 | if done || used == 0 { |
c34b1796 | 1280 | return Ok(read); |
1a4d82fc JJ |
1281 | } |
1282 | } | |
1283 | } | |
1284 | ||
c1a9b12d SL |
1285 | /// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it |
1286 | /// to perform extra ways of reading. | |
1287 | /// | |
1288 | /// For example, reading line-by-line is inefficient without using a buffer, so | |
1289 | /// if you want to read by line, you'll need `BufRead`, which includes a | |
cc61c64b | 1290 | /// [`read_line`] method as well as a [`lines`] iterator. |
c1a9b12d SL |
1291 | /// |
1292 | /// # Examples | |
1293 | /// | |
1294 | /// A locked standard input implements `BufRead`: | |
1295 | /// | |
1296 | /// ``` | |
1297 | /// use std::io; | |
1298 | /// use std::io::prelude::*; | |
1299 | /// | |
1300 | /// let stdin = io::stdin(); | |
1301 | /// for line in stdin.lock().lines() { | |
1302 | /// println!("{}", line.unwrap()); | |
1303 | /// } | |
1304 | /// ``` | |
1305 | /// | |
c30ab7b3 SL |
1306 | /// If you have something that implements [`Read`], you can use the [`BufReader` |
1307 | /// type][`BufReader`] to turn it into a `BufRead`. | |
c1a9b12d | 1308 | /// |
c30ab7b3 SL |
1309 | /// For example, [`File`] implements [`Read`], but not `BufRead`. |
1310 | /// [`BufReader`] to the rescue! | |
85aaf69f | 1311 | /// |
c30ab7b3 SL |
1312 | /// [`BufReader`]: struct.BufReader.html |
1313 | /// [`File`]: ../fs/struct.File.html | |
cc61c64b XL |
1314 | /// [`read_line`]: #method.read_line |
1315 | /// [`lines`]: #method.lines | |
c30ab7b3 | 1316 | /// [`Read`]: trait.Read.html |
c1a9b12d SL |
1317 | /// |
1318 | /// ``` | |
1319 | /// use std::io::{self, BufReader}; | |
1320 | /// use std::io::prelude::*; | |
1321 | /// use std::fs::File; | |
1322 | /// | |
1323 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 1324 | /// let f = File::open("foo.txt")?; |
c1a9b12d SL |
1325 | /// let f = BufReader::new(f); |
1326 | /// | |
1327 | /// for line in f.lines() { | |
1328 | /// println!("{}", line.unwrap()); | |
1329 | /// } | |
1330 | /// | |
1331 | /// # Ok(()) | |
1332 | /// # } | |
1333 | /// ``` | |
62682a34 | 1334 | /// |
c34b1796 | 1335 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1336 | pub trait BufRead: Read { |
1a4d82fc | 1337 | /// Fills the internal buffer of this object, returning the buffer contents. |
85aaf69f | 1338 | /// |
c1a9b12d | 1339 | /// This function is a lower-level call. It needs to be paired with the |
cc61c64b | 1340 | /// [`consume`] method to function properly. When calling this |
c1a9b12d | 1341 | /// method, none of the contents will be "read" in the sense that later |
cc61c64b | 1342 | /// calling `read` may return the same contents. As such, [`consume`] must |
c30ab7b3 | 1343 | /// be called with the number of bytes that are consumed from this buffer to |
c1a9b12d | 1344 | /// ensure that the bytes are never returned twice. |
1a4d82fc | 1345 | /// |
cc61c64b | 1346 | /// [`consume`]: #tymethod.consume |
1a4d82fc | 1347 | /// |
85aaf69f SL |
1348 | /// An empty buffer returned indicates that the stream has reached EOF. |
1349 | /// | |
1350 | /// # Errors | |
1a4d82fc JJ |
1351 | /// |
1352 | /// This function will return an I/O error if the underlying reader was | |
85aaf69f | 1353 | /// read, but returned an error. |
c1a9b12d SL |
1354 | /// |
1355 | /// # Examples | |
1356 | /// | |
1357 | /// A locked standard input implements `BufRead`: | |
1358 | /// | |
1359 | /// ``` | |
1360 | /// use std::io; | |
1361 | /// use std::io::prelude::*; | |
1362 | /// | |
1363 | /// let stdin = io::stdin(); | |
1364 | /// let mut stdin = stdin.lock(); | |
1365 | /// | |
1366 | /// // we can't have two `&mut` references to `stdin`, so use a block | |
1367 | /// // to end the borrow early. | |
1368 | /// let length = { | |
1369 | /// let buffer = stdin.fill_buf().unwrap(); | |
1370 | /// | |
1371 | /// // work with buffer | |
1372 | /// println!("{:?}", buffer); | |
1373 | /// | |
1374 | /// buffer.len() | |
1375 | /// }; | |
1376 | /// | |
1377 | /// // ensure the bytes we worked with aren't returned again later | |
1378 | /// stdin.consume(length); | |
1379 | /// ``` | |
c34b1796 | 1380 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1381 | fn fill_buf(&mut self) -> Result<&[u8]>; |
1a4d82fc JJ |
1382 | |
1383 | /// Tells this buffer that `amt` bytes have been consumed from the buffer, | |
1384 | /// so they should no longer be returned in calls to `read`. | |
c34b1796 | 1385 | /// |
c1a9b12d | 1386 | /// This function is a lower-level call. It needs to be paired with the |
cc61c64b | 1387 | /// [`fill_buf`] method to function properly. This function does |
c1a9b12d | 1388 | /// not perform any I/O, it simply informs this object that some amount of |
cc61c64b | 1389 | /// its buffer, returned from [`fill_buf`], has been consumed and should |
c30ab7b3 | 1390 | /// no longer be returned. As such, this function may do odd things if |
cc61c64b | 1391 | /// [`fill_buf`] isn't called before calling it. |
c1a9b12d SL |
1392 | /// |
1393 | /// The `amt` must be `<=` the number of bytes in the buffer returned by | |
cc61c64b | 1394 | /// [`fill_buf`]. |
c34b1796 | 1395 | /// |
c1a9b12d | 1396 | /// # Examples |
c34b1796 | 1397 | /// |
cc61c64b | 1398 | /// Since `consume()` is meant to be used with [`fill_buf`], |
c1a9b12d | 1399 | /// that method's example includes an example of `consume()`. |
c30ab7b3 | 1400 | /// |
cc61c64b | 1401 | /// [`fill_buf`]: #tymethod.fill_buf |
c34b1796 | 1402 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1403 | fn consume(&mut self, amt: usize); |
1a4d82fc | 1404 | |
c30ab7b3 | 1405 | /// Read all bytes into `buf` until the delimiter `byte` or EOF is reached. |
1a4d82fc | 1406 | /// |
c1a9b12d SL |
1407 | /// This function will read bytes from the underlying stream until the |
1408 | /// delimiter or EOF is found. Once found, all bytes up to, and including, | |
1409 | /// the delimiter (if found) will be appended to `buf`. | |
1a4d82fc | 1410 | /// |
c30ab7b3 | 1411 | /// If successful, this function will return the total number of bytes read. |
1a4d82fc | 1412 | /// |
85aaf69f | 1413 | /// # Errors |
1a4d82fc | 1414 | /// |
c30ab7b3 | 1415 | /// This function will ignore all instances of [`ErrorKind::Interrupted`] and |
cc61c64b | 1416 | /// will otherwise return any errors returned by [`fill_buf`]. |
1a4d82fc | 1417 | /// |
85aaf69f SL |
1418 | /// If an I/O error is encountered then all bytes read so far will be |
1419 | /// present in `buf` and its length will have been adjusted appropriately. | |
c1a9b12d | 1420 | /// |
cc61c64b | 1421 | /// [`fill_buf`]: #tymethod.fill_buf |
c30ab7b3 SL |
1422 | /// [`ErrorKind::Interrupted`]: enum.ErrorKind.html#variant.Interrupted |
1423 | /// | |
cc61c64b | 1424 | /// # Examples |
c1a9b12d | 1425 | /// |
cc61c64b XL |
1426 | /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In |
1427 | /// this example, we use [`Cursor`] to read all the bytes in a byte slice | |
1428 | /// in hyphen delimited segments: | |
c1a9b12d | 1429 | /// |
cc61c64b | 1430 | /// [`Cursor`]: struct.Cursor.html |
c1a9b12d | 1431 | /// |
cc61c64b XL |
1432 | /// ``` |
1433 | /// use std::io::{self, BufRead}; | |
1434 | /// | |
1435 | /// let mut cursor = io::Cursor::new(b"lorem-ipsum"); | |
1436 | /// let mut buf = vec![]; | |
1437 | /// | |
1438 | /// // cursor is at 'l' | |
1439 | /// let num_bytes = cursor.read_until(b'-', &mut buf) | |
1440 | /// .expect("reading from cursor won't fail"); | |
1441 | /// assert_eq!(num_bytes, 6); | |
1442 | /// assert_eq!(buf, b"lorem-"); | |
1443 | /// buf.clear(); | |
1444 | /// | |
1445 | /// // cursor is at 'i' | |
1446 | /// let num_bytes = cursor.read_until(b'-', &mut buf) | |
1447 | /// .expect("reading from cursor won't fail"); | |
1448 | /// assert_eq!(num_bytes, 5); | |
1449 | /// assert_eq!(buf, b"ipsum"); | |
1450 | /// buf.clear(); | |
1451 | /// | |
1452 | /// // cursor is at EOF | |
1453 | /// let num_bytes = cursor.read_until(b'-', &mut buf) | |
1454 | /// .expect("reading from cursor won't fail"); | |
1455 | /// assert_eq!(num_bytes, 0); | |
1456 | /// assert_eq!(buf, b""); | |
c1a9b12d | 1457 | /// ``` |
c34b1796 AL |
1458 | #[stable(feature = "rust1", since = "1.0.0")] |
1459 | fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> { | |
85aaf69f | 1460 | read_until(self, byte, buf) |
1a4d82fc JJ |
1461 | } |
1462 | ||
c1a9b12d SL |
1463 | /// Read all bytes until a newline (the 0xA byte) is reached, and append |
1464 | /// them to the provided buffer. | |
1a4d82fc | 1465 | /// |
c1a9b12d SL |
1466 | /// This function will read bytes from the underlying stream until the |
1467 | /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes | |
1468 | /// up to, and including, the delimiter (if found) will be appended to | |
1469 | /// `buf`. | |
1a4d82fc | 1470 | /// |
c30ab7b3 | 1471 | /// If successful, this function will return the total number of bytes read. |
85aaf69f SL |
1472 | /// |
1473 | /// # Errors | |
1474 | /// | |
cc61c64b | 1475 | /// This function has the same error semantics as [`read_until`] and will |
c30ab7b3 SL |
1476 | /// also return an error if the read bytes are not valid UTF-8. If an I/O |
1477 | /// error is encountered then `buf` may contain some bytes already read in | |
1478 | /// the event that all data read so far was valid UTF-8. | |
c1a9b12d SL |
1479 | /// |
1480 | /// # Examples | |
1481 | /// | |
cc61c64b XL |
1482 | /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In |
1483 | /// this example, we use [`Cursor`] to read all the lines in a byte slice: | |
c1a9b12d | 1484 | /// |
cc61c64b | 1485 | /// [`Cursor`]: struct.Cursor.html |
c1a9b12d SL |
1486 | /// |
1487 | /// ``` | |
cc61c64b XL |
1488 | /// use std::io::{self, BufRead}; |
1489 | /// | |
1490 | /// let mut cursor = io::Cursor::new(b"foo\nbar"); | |
1491 | /// let mut buf = String::new(); | |
1492 | /// | |
1493 | /// // cursor is at 'f' | |
1494 | /// let num_bytes = cursor.read_line(&mut buf) | |
1495 | /// .expect("reading from cursor won't fail"); | |
1496 | /// assert_eq!(num_bytes, 4); | |
1497 | /// assert_eq!(buf, "foo\n"); | |
1498 | /// buf.clear(); | |
1499 | /// | |
1500 | /// // cursor is at 'b' | |
1501 | /// let num_bytes = cursor.read_line(&mut buf) | |
1502 | /// .expect("reading from cursor won't fail"); | |
1503 | /// assert_eq!(num_bytes, 3); | |
1504 | /// assert_eq!(buf, "bar"); | |
1505 | /// buf.clear(); | |
1506 | /// | |
1507 | /// // cursor is at EOF | |
1508 | /// let num_bytes = cursor.read_line(&mut buf) | |
1509 | /// .expect("reading from cursor won't fail"); | |
1510 | /// assert_eq!(num_bytes, 0); | |
1511 | /// assert_eq!(buf, ""); | |
c1a9b12d | 1512 | /// ``` |
c34b1796 AL |
1513 | #[stable(feature = "rust1", since = "1.0.0")] |
1514 | fn read_line(&mut self, buf: &mut String) -> Result<usize> { | |
85aaf69f SL |
1515 | // Note that we are not calling the `.read_until` method here, but |
1516 | // rather our hardcoded implementation. For more details as to why, see | |
1517 | // the comments in `read_to_end`. | |
1518 | append_to_string(buf, |b| read_until(self, b'\n', b)) | |
1a4d82fc | 1519 | } |
1a4d82fc | 1520 | |
85aaf69f SL |
1521 | /// Returns an iterator over the contents of this reader split on the byte |
1522 | /// `byte`. | |
1a4d82fc | 1523 | /// |
85aaf69f | 1524 | /// The iterator returned from this function will return instances of |
c30ab7b3 SL |
1525 | /// [`io::Result`]`<`[`Vec<u8>`]`>`. Each vector returned will *not* have |
1526 | /// the delimiter byte at the end. | |
1a4d82fc | 1527 | /// |
cc61c64b | 1528 | /// This function will yield errors whenever [`read_until`] would have |
c30ab7b3 | 1529 | /// also yielded an error. |
c1a9b12d | 1530 | /// |
cc61c64b XL |
1531 | /// [`io::Result`]: type.Result.html |
1532 | /// [`Vec<u8>`]: ../vec/struct.Vec.html | |
1533 | /// [`read_until`]: #method.read_until | |
1534 | /// | |
c1a9b12d SL |
1535 | /// # Examples |
1536 | /// | |
cc61c64b XL |
1537 | /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In |
1538 | /// this example, we use [`Cursor`] to iterate over all hyphen delimited | |
1539 | /// segments in a byte slice | |
c1a9b12d | 1540 | /// |
cc61c64b | 1541 | /// [`Cursor`]: struct.Cursor.html |
c30ab7b3 | 1542 | /// |
c1a9b12d | 1543 | /// ``` |
cc61c64b | 1544 | /// use std::io::{self, BufRead}; |
c1a9b12d | 1545 | /// |
cc61c64b | 1546 | /// let cursor = io::Cursor::new(b"lorem-ipsum-dolor"); |
c1a9b12d | 1547 | /// |
cc61c64b XL |
1548 | /// let mut split_iter = cursor.split(b'-').map(|l| l.unwrap()); |
1549 | /// assert_eq!(split_iter.next(), Some(b"lorem".to_vec())); | |
1550 | /// assert_eq!(split_iter.next(), Some(b"ipsum".to_vec())); | |
1551 | /// assert_eq!(split_iter.next(), Some(b"dolor".to_vec())); | |
1552 | /// assert_eq!(split_iter.next(), None); | |
c1a9b12d | 1553 | /// ``` |
c34b1796 AL |
1554 | #[stable(feature = "rust1", since = "1.0.0")] |
1555 | fn split(self, byte: u8) -> Split<Self> where Self: Sized { | |
85aaf69f SL |
1556 | Split { buf: self, delim: byte } |
1557 | } | |
1a4d82fc | 1558 | |
85aaf69f | 1559 | /// Returns an iterator over the lines of this reader. |
1a4d82fc | 1560 | /// |
85aaf69f | 1561 | /// The iterator returned from this function will yield instances of |
c30ab7b3 | 1562 | /// [`io::Result`]`<`[`String`]`>`. Each string returned will *not* have a newline |
e9174d1e | 1563 | /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end. |
c1a9b12d | 1564 | /// |
c30ab7b3 SL |
1565 | /// [`io::Result`]: type.Result.html |
1566 | /// [`String`]: ../string/struct.String.html | |
1567 | /// | |
c1a9b12d SL |
1568 | /// # Examples |
1569 | /// | |
cc61c64b XL |
1570 | /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In |
1571 | /// this example, we use [`Cursor`] to iterate over all the lines in a byte | |
1572 | /// slice. | |
1573 | /// | |
1574 | /// [`Cursor`]: struct.Cursor.html | |
c1a9b12d SL |
1575 | /// |
1576 | /// ``` | |
cc61c64b | 1577 | /// use std::io::{self, BufRead}; |
c1a9b12d | 1578 | /// |
cc61c64b | 1579 | /// let cursor = io::Cursor::new(b"lorem\nipsum\r\ndolor"); |
c1a9b12d | 1580 | /// |
cc61c64b XL |
1581 | /// let mut lines_iter = cursor.lines().map(|l| l.unwrap()); |
1582 | /// assert_eq!(lines_iter.next(), Some(String::from("lorem"))); | |
1583 | /// assert_eq!(lines_iter.next(), Some(String::from("ipsum"))); | |
1584 | /// assert_eq!(lines_iter.next(), Some(String::from("dolor"))); | |
1585 | /// assert_eq!(lines_iter.next(), None); | |
c1a9b12d | 1586 | /// ``` |
32a655c1 SL |
1587 | /// |
1588 | /// # Errors | |
1589 | /// | |
cc61c64b | 1590 | /// Each line of the iterator has the same error semantics as [`BufRead::read_line`]. |
32a655c1 | 1591 | /// |
cc61c64b | 1592 | /// [`BufRead::read_line`]: trait.BufRead.html#method.read_line |
c34b1796 AL |
1593 | #[stable(feature = "rust1", since = "1.0.0")] |
1594 | fn lines(self) -> Lines<Self> where Self: Sized { | |
85aaf69f SL |
1595 | Lines { buf: self } |
1596 | } | |
1597 | } | |
1598 | ||
c1a9b12d SL |
1599 | /// Adaptor to chain together two readers. |
1600 | /// | |
cc61c64b XL |
1601 | /// This struct is generally created by calling [`chain`] on a reader. |
1602 | /// Please see the documentation of [`chain`] for more details. | |
85aaf69f | 1603 | /// |
cc61c64b | 1604 | /// [`chain`]: trait.Read.html#method.chain |
c34b1796 | 1605 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
1606 | pub struct Chain<T, U> { |
1607 | first: T, | |
1608 | second: U, | |
1609 | done_first: bool, | |
1a4d82fc JJ |
1610 | } |
1611 | ||
7cac9316 XL |
1612 | impl<T, U> Chain<T, U> { |
1613 | /// Consumes the `Chain`, returning the wrapped readers. | |
1614 | /// | |
1615 | /// # Examples | |
1616 | /// | |
1617 | /// ``` | |
7cac9316 XL |
1618 | /// # use std::io; |
1619 | /// use std::io::prelude::*; | |
1620 | /// use std::fs::File; | |
1621 | /// | |
1622 | /// # fn foo() -> io::Result<()> { | |
1623 | /// let mut foo_file = File::open("foo.txt")?; | |
1624 | /// let mut bar_file = File::open("bar.txt")?; | |
1625 | /// | |
1626 | /// let chain = foo_file.chain(bar_file); | |
1627 | /// let (foo_file, bar_file) = chain.into_inner(); | |
1628 | /// # Ok(()) | |
1629 | /// # } | |
1630 | /// ``` | |
041b39d2 | 1631 | #[stable(feature = "more_io_inner_methods", since = "1.20.0")] |
7cac9316 XL |
1632 | pub fn into_inner(self) -> (T, U) { |
1633 | (self.first, self.second) | |
1634 | } | |
1635 | ||
1636 | /// Gets references to the underlying readers in this `Chain`. | |
1637 | /// | |
1638 | /// # Examples | |
1639 | /// | |
1640 | /// ``` | |
7cac9316 XL |
1641 | /// # use std::io; |
1642 | /// use std::io::prelude::*; | |
1643 | /// use std::fs::File; | |
1644 | /// | |
1645 | /// # fn foo() -> io::Result<()> { | |
1646 | /// let mut foo_file = File::open("foo.txt")?; | |
1647 | /// let mut bar_file = File::open("bar.txt")?; | |
1648 | /// | |
1649 | /// let chain = foo_file.chain(bar_file); | |
1650 | /// let (foo_file, bar_file) = chain.get_ref(); | |
1651 | /// # Ok(()) | |
1652 | /// # } | |
1653 | /// ``` | |
041b39d2 | 1654 | #[stable(feature = "more_io_inner_methods", since = "1.20.0")] |
7cac9316 XL |
1655 | pub fn get_ref(&self) -> (&T, &U) { |
1656 | (&self.first, &self.second) | |
1657 | } | |
1658 | ||
1659 | /// Gets mutable references to the underlying readers in this `Chain`. | |
1660 | /// | |
1661 | /// Care should be taken to avoid modifying the internal I/O state of the | |
1662 | /// underlying readers as doing so may corrupt the internal state of this | |
1663 | /// `Chain`. | |
1664 | /// | |
1665 | /// # Examples | |
1666 | /// | |
1667 | /// ``` | |
7cac9316 XL |
1668 | /// # use std::io; |
1669 | /// use std::io::prelude::*; | |
1670 | /// use std::fs::File; | |
1671 | /// | |
1672 | /// # fn foo() -> io::Result<()> { | |
1673 | /// let mut foo_file = File::open("foo.txt")?; | |
1674 | /// let mut bar_file = File::open("bar.txt")?; | |
1675 | /// | |
1676 | /// let mut chain = foo_file.chain(bar_file); | |
1677 | /// let (foo_file, bar_file) = chain.get_mut(); | |
1678 | /// # Ok(()) | |
1679 | /// # } | |
1680 | /// ``` | |
041b39d2 | 1681 | #[stable(feature = "more_io_inner_methods", since = "1.20.0")] |
7cac9316 XL |
1682 | pub fn get_mut(&mut self) -> (&mut T, &mut U) { |
1683 | (&mut self.first, &mut self.second) | |
1684 | } | |
1685 | } | |
1686 | ||
8bb4bdeb | 1687 | #[stable(feature = "std_debug", since = "1.16.0")] |
32a655c1 SL |
1688 | impl<T: fmt::Debug, U: fmt::Debug> fmt::Debug for Chain<T, U> { |
1689 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1690 | f.debug_struct("Chain") | |
1691 | .field("t", &self.first) | |
1692 | .field("u", &self.second) | |
1693 | .finish() | |
1694 | } | |
1695 | } | |
1696 | ||
c34b1796 | 1697 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
1698 | impl<T: Read, U: Read> Read for Chain<T, U> { |
1699 | fn read(&mut self, buf: &mut [u8]) -> Result<usize> { | |
1700 | if !self.done_first { | |
54a0048b | 1701 | match self.first.read(buf)? { |
c30ab7b3 | 1702 | 0 if buf.len() != 0 => { self.done_first = true; } |
85aaf69f SL |
1703 | n => return Ok(n), |
1704 | } | |
1705 | } | |
1706 | self.second.read(buf) | |
1707 | } | |
041b39d2 XL |
1708 | |
1709 | unsafe fn initializer(&self) -> Initializer { | |
1710 | let initializer = self.first.initializer(); | |
1711 | if initializer.should_initialize() { | |
1712 | initializer | |
1713 | } else { | |
1714 | self.second.initializer() | |
1715 | } | |
1716 | } | |
1a4d82fc JJ |
1717 | } |
1718 | ||
54a0048b SL |
1719 | #[stable(feature = "chain_bufread", since = "1.9.0")] |
1720 | impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> { | |
1721 | fn fill_buf(&mut self) -> Result<&[u8]> { | |
1722 | if !self.done_first { | |
1723 | match self.first.fill_buf()? { | |
1724 | buf if buf.len() == 0 => { self.done_first = true; } | |
1725 | buf => return Ok(buf), | |
1726 | } | |
1727 | } | |
1728 | self.second.fill_buf() | |
1729 | } | |
1730 | ||
1731 | fn consume(&mut self, amt: usize) { | |
1732 | if !self.done_first { | |
1733 | self.first.consume(amt) | |
1734 | } else { | |
1735 | self.second.consume(amt) | |
1736 | } | |
1737 | } | |
1738 | } | |
1739 | ||
85aaf69f | 1740 | /// Reader adaptor which limits the bytes read from an underlying reader. |
1a4d82fc | 1741 | /// |
cc61c64b XL |
1742 | /// This struct is generally created by calling [`take`] on a reader. |
1743 | /// Please see the documentation of [`take`] for more details. | |
c1a9b12d | 1744 | /// |
cc61c64b | 1745 | /// [`take`]: trait.Read.html#method.take |
c34b1796 | 1746 | #[stable(feature = "rust1", since = "1.0.0")] |
32a655c1 | 1747 | #[derive(Debug)] |
85aaf69f SL |
1748 | pub struct Take<T> { |
1749 | inner: T, | |
1750 | limit: u64, | |
1a4d82fc JJ |
1751 | } |
1752 | ||
85aaf69f SL |
1753 | impl<T> Take<T> { |
1754 | /// Returns the number of bytes that can be read before this instance will | |
1755 | /// return EOF. | |
1a4d82fc | 1756 | /// |
85aaf69f | 1757 | /// # Note |
1a4d82fc | 1758 | /// |
476ff2be SL |
1759 | /// This instance may reach `EOF` after reading fewer bytes than indicated by |
1760 | /// this method if the underlying [`Read`] instance reaches EOF. | |
1761 | /// | |
1762 | /// [`Read`]: ../../std/io/trait.Read.html | |
5bcae85e SL |
1763 | /// |
1764 | /// # Examples | |
1765 | /// | |
1766 | /// ``` | |
1767 | /// use std::io; | |
1768 | /// use std::io::prelude::*; | |
1769 | /// use std::fs::File; | |
1770 | /// | |
1771 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 1772 | /// let f = File::open("foo.txt")?; |
5bcae85e SL |
1773 | /// |
1774 | /// // read at most five bytes | |
1775 | /// let handle = f.take(5); | |
1776 | /// | |
1777 | /// println!("limit: {}", handle.limit()); | |
1778 | /// # Ok(()) | |
1779 | /// # } | |
1780 | /// ``` | |
c34b1796 | 1781 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1782 | pub fn limit(&self) -> u64 { self.limit } |
9e0c209e | 1783 | |
041b39d2 XL |
1784 | /// Sets the number of bytes that can be read before this instance will |
1785 | /// return EOF. This is the same as constructing a new `Take` instance, so | |
1786 | /// the amount of bytes read and the previous limit value don't matter when | |
1787 | /// calling this method. | |
1788 | /// | |
1789 | /// # Examples | |
1790 | /// | |
1791 | /// ``` | |
1792 | /// #![feature(take_set_limit)] | |
1793 | /// use std::io; | |
1794 | /// use std::io::prelude::*; | |
1795 | /// use std::fs::File; | |
1796 | /// | |
1797 | /// # fn foo() -> io::Result<()> { | |
1798 | /// let f = File::open("foo.txt")?; | |
1799 | /// | |
1800 | /// // read at most five bytes | |
1801 | /// let mut handle = f.take(5); | |
1802 | /// handle.set_limit(10); | |
1803 | /// | |
1804 | /// assert_eq!(handle.limit(), 10); | |
1805 | /// # Ok(()) | |
1806 | /// # } | |
1807 | /// ``` | |
1808 | #[unstable(feature = "take_set_limit", issue = "42781")] | |
1809 | pub fn set_limit(&mut self, limit: u64) { | |
1810 | self.limit = limit; | |
1811 | } | |
1812 | ||
9e0c209e SL |
1813 | /// Consumes the `Take`, returning the wrapped reader. |
1814 | /// | |
1815 | /// # Examples | |
1816 | /// | |
1817 | /// ``` | |
9e0c209e SL |
1818 | /// use std::io; |
1819 | /// use std::io::prelude::*; | |
1820 | /// use std::fs::File; | |
1821 | /// | |
1822 | /// # fn foo() -> io::Result<()> { | |
32a655c1 | 1823 | /// let mut file = File::open("foo.txt")?; |
9e0c209e SL |
1824 | /// |
1825 | /// let mut buffer = [0; 5]; | |
1826 | /// let mut handle = file.take(5); | |
32a655c1 | 1827 | /// handle.read(&mut buffer)?; |
9e0c209e SL |
1828 | /// |
1829 | /// let file = handle.into_inner(); | |
1830 | /// # Ok(()) | |
1831 | /// # } | |
1832 | /// ``` | |
476ff2be | 1833 | #[stable(feature = "io_take_into_inner", since = "1.15.0")] |
9e0c209e SL |
1834 | pub fn into_inner(self) -> T { |
1835 | self.inner | |
1836 | } | |
7cac9316 XL |
1837 | |
1838 | /// Gets a reference to the underlying reader. | |
1839 | /// | |
1840 | /// # Examples | |
1841 | /// | |
1842 | /// ``` | |
7cac9316 XL |
1843 | /// use std::io; |
1844 | /// use std::io::prelude::*; | |
1845 | /// use std::fs::File; | |
1846 | /// | |
1847 | /// # fn foo() -> io::Result<()> { | |
1848 | /// let mut file = File::open("foo.txt")?; | |
1849 | /// | |
1850 | /// let mut buffer = [0; 5]; | |
1851 | /// let mut handle = file.take(5); | |
1852 | /// handle.read(&mut buffer)?; | |
1853 | /// | |
1854 | /// let file = handle.get_ref(); | |
1855 | /// # Ok(()) | |
1856 | /// # } | |
1857 | /// ``` | |
041b39d2 | 1858 | #[stable(feature = "more_io_inner_methods", since = "1.20.0")] |
7cac9316 XL |
1859 | pub fn get_ref(&self) -> &T { |
1860 | &self.inner | |
1861 | } | |
1862 | ||
1863 | /// Gets a mutable reference to the underlying reader. | |
1864 | /// | |
1865 | /// Care should be taken to avoid modifying the internal I/O state of the | |
1866 | /// underlying reader as doing so may corrupt the internal limit of this | |
1867 | /// `Take`. | |
1868 | /// | |
1869 | /// # Examples | |
1870 | /// | |
1871 | /// ``` | |
7cac9316 XL |
1872 | /// use std::io; |
1873 | /// use std::io::prelude::*; | |
1874 | /// use std::fs::File; | |
1875 | /// | |
1876 | /// # fn foo() -> io::Result<()> { | |
1877 | /// let mut file = File::open("foo.txt")?; | |
1878 | /// | |
1879 | /// let mut buffer = [0; 5]; | |
1880 | /// let mut handle = file.take(5); | |
1881 | /// handle.read(&mut buffer)?; | |
1882 | /// | |
1883 | /// let file = handle.get_mut(); | |
1884 | /// # Ok(()) | |
1885 | /// # } | |
1886 | /// ``` | |
041b39d2 | 1887 | #[stable(feature = "more_io_inner_methods", since = "1.20.0")] |
7cac9316 XL |
1888 | pub fn get_mut(&mut self) -> &mut T { |
1889 | &mut self.inner | |
1890 | } | |
85aaf69f | 1891 | } |
1a4d82fc | 1892 | |
c34b1796 | 1893 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
1894 | impl<T: Read> Read for Take<T> { |
1895 | fn read(&mut self, buf: &mut [u8]) -> Result<usize> { | |
c34b1796 AL |
1896 | // Don't call into inner reader at all at EOF because it may still block |
1897 | if self.limit == 0 { | |
1898 | return Ok(0); | |
1899 | } | |
1900 | ||
85aaf69f | 1901 | let max = cmp::min(buf.len() as u64, self.limit) as usize; |
54a0048b | 1902 | let n = self.inner.read(&mut buf[..max])?; |
85aaf69f SL |
1903 | self.limit -= n as u64; |
1904 | Ok(n) | |
1a4d82fc | 1905 | } |
041b39d2 XL |
1906 | |
1907 | unsafe fn initializer(&self) -> Initializer { | |
1908 | self.inner.initializer() | |
1909 | } | |
1a4d82fc JJ |
1910 | } |
1911 | ||
c34b1796 AL |
1912 | #[stable(feature = "rust1", since = "1.0.0")] |
1913 | impl<T: BufRead> BufRead for Take<T> { | |
1914 | fn fill_buf(&mut self) -> Result<&[u8]> { | |
a7813a04 XL |
1915 | // Don't call into inner reader at all at EOF because it may still block |
1916 | if self.limit == 0 { | |
1917 | return Ok(&[]); | |
1918 | } | |
1919 | ||
54a0048b | 1920 | let buf = self.inner.fill_buf()?; |
c34b1796 AL |
1921 | let cap = cmp::min(buf.len() as u64, self.limit) as usize; |
1922 | Ok(&buf[..cap]) | |
1923 | } | |
1924 | ||
1925 | fn consume(&mut self, amt: usize) { | |
1926 | // Don't let callers reset the limit by passing an overlarge value | |
1927 | let amt = cmp::min(amt as u64, self.limit) as usize; | |
1928 | self.limit -= amt as u64; | |
1929 | self.inner.consume(amt); | |
1930 | } | |
1931 | } | |
1932 | ||
5bcae85e SL |
1933 | fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> { |
1934 | let mut buf = [0]; | |
1935 | loop { | |
1936 | return match reader.read(&mut buf) { | |
1937 | Ok(0) => None, | |
1938 | Ok(..) => Some(Ok(buf[0])), | |
1939 | Err(ref e) if e.kind() == ErrorKind::Interrupted => continue, | |
1940 | Err(e) => Some(Err(e)), | |
1941 | }; | |
1942 | } | |
1943 | } | |
1944 | ||
c1a9b12d SL |
1945 | /// An iterator over `u8` values of a reader. |
1946 | /// | |
cc61c64b XL |
1947 | /// This struct is generally created by calling [`bytes`] on a reader. |
1948 | /// Please see the documentation of [`bytes`] for more details. | |
1a4d82fc | 1949 | /// |
cc61c64b | 1950 | /// [`bytes`]: trait.Read.html#method.bytes |
c34b1796 | 1951 | #[stable(feature = "rust1", since = "1.0.0")] |
32a655c1 | 1952 | #[derive(Debug)] |
85aaf69f SL |
1953 | pub struct Bytes<R> { |
1954 | inner: R, | |
1a4d82fc JJ |
1955 | } |
1956 | ||
c34b1796 | 1957 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
1958 | impl<R: Read> Iterator for Bytes<R> { |
1959 | type Item = Result<u8>; | |
1a4d82fc | 1960 | |
85aaf69f | 1961 | fn next(&mut self) -> Option<Result<u8>> { |
5bcae85e | 1962 | read_one_byte(&mut self.inner) |
85aaf69f | 1963 | } |
1a4d82fc JJ |
1964 | } |
1965 | ||
c1a9b12d | 1966 | /// An iterator over the `char`s of a reader. |
1a4d82fc | 1967 | /// |
cc61c64b | 1968 | /// This struct is generally created by calling [`chars`][chars] on a reader. |
c1a9b12d SL |
1969 | /// Please see the documentation of `chars()` for more details. |
1970 | /// | |
1971 | /// [chars]: trait.Read.html#method.chars | |
e9174d1e SL |
1972 | #[unstable(feature = "io", reason = "awaiting stability of Read::chars", |
1973 | issue = "27802")] | |
32a655c1 | 1974 | #[derive(Debug)] |
85aaf69f SL |
1975 | pub struct Chars<R> { |
1976 | inner: R, | |
1a4d82fc JJ |
1977 | } |
1978 | ||
85aaf69f SL |
1979 | /// An enumeration of possible errors that can be generated from the `Chars` |
1980 | /// adapter. | |
c34b1796 | 1981 | #[derive(Debug)] |
e9174d1e SL |
1982 | #[unstable(feature = "io", reason = "awaiting stability of Read::chars", |
1983 | issue = "27802")] | |
85aaf69f SL |
1984 | pub enum CharsError { |
1985 | /// Variant representing that the underlying stream was read successfully | |
1986 | /// but it did not contain valid utf8 data. | |
1987 | NotUtf8, | |
1a4d82fc | 1988 | |
85aaf69f SL |
1989 | /// Variant representing that an I/O error occurred. |
1990 | Other(Error), | |
1a4d82fc JJ |
1991 | } |
1992 | ||
e9174d1e SL |
1993 | #[unstable(feature = "io", reason = "awaiting stability of Read::chars", |
1994 | issue = "27802")] | |
85aaf69f SL |
1995 | impl<R: Read> Iterator for Chars<R> { |
1996 | type Item = result::Result<char, CharsError>; | |
1a4d82fc | 1997 | |
85aaf69f | 1998 | fn next(&mut self) -> Option<result::Result<char, CharsError>> { |
5bcae85e SL |
1999 | let first_byte = match read_one_byte(&mut self.inner) { |
2000 | None => return None, | |
2001 | Some(Ok(b)) => b, | |
2002 | Some(Err(e)) => return Some(Err(CharsError::Other(e))), | |
85aaf69f SL |
2003 | }; |
2004 | let width = core_str::utf8_char_width(first_byte); | |
2005 | if width == 1 { return Some(Ok(first_byte as char)) } | |
2006 | if width == 0 { return Some(Err(CharsError::NotUtf8)) } | |
2007 | let mut buf = [first_byte, 0, 0, 0]; | |
2008 | { | |
2009 | let mut start = 1; | |
2010 | while start < width { | |
2011 | match self.inner.read(&mut buf[start..width]) { | |
2012 | Ok(0) => return Some(Err(CharsError::NotUtf8)), | |
2013 | Ok(n) => start += n, | |
5bcae85e | 2014 | Err(ref e) if e.kind() == ErrorKind::Interrupted => continue, |
85aaf69f SL |
2015 | Err(e) => return Some(Err(CharsError::Other(e))), |
2016 | } | |
2017 | } | |
2018 | } | |
2019 | Some(match str::from_utf8(&buf[..width]).ok() { | |
54a0048b | 2020 | Some(s) => Ok(s.chars().next().unwrap()), |
85aaf69f SL |
2021 | None => Err(CharsError::NotUtf8), |
2022 | }) | |
2023 | } | |
1a4d82fc JJ |
2024 | } |
2025 | ||
e9174d1e SL |
2026 | #[unstable(feature = "io", reason = "awaiting stability of Read::chars", |
2027 | issue = "27802")] | |
c34b1796 | 2028 | impl std_error::Error for CharsError { |
85aaf69f SL |
2029 | fn description(&self) -> &str { |
2030 | match *self { | |
2031 | CharsError::NotUtf8 => "invalid utf8 encoding", | |
c34b1796 | 2032 | CharsError::Other(ref e) => std_error::Error::description(e), |
85aaf69f SL |
2033 | } |
2034 | } | |
c34b1796 | 2035 | fn cause(&self) -> Option<&std_error::Error> { |
85aaf69f SL |
2036 | match *self { |
2037 | CharsError::NotUtf8 => None, | |
2038 | CharsError::Other(ref e) => e.cause(), | |
2039 | } | |
1a4d82fc JJ |
2040 | } |
2041 | } | |
2042 | ||
e9174d1e SL |
2043 | #[unstable(feature = "io", reason = "awaiting stability of Read::chars", |
2044 | issue = "27802")] | |
85aaf69f | 2045 | impl fmt::Display for CharsError { |
1a4d82fc | 2046 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
85aaf69f SL |
2047 | match *self { |
2048 | CharsError::NotUtf8 => { | |
2049 | "byte stream did not contain valid utf8".fmt(f) | |
2050 | } | |
2051 | CharsError::Other(ref e) => e.fmt(f), | |
2052 | } | |
1a4d82fc JJ |
2053 | } |
2054 | } | |
2055 | ||
85aaf69f SL |
2056 | /// An iterator over the contents of an instance of `BufRead` split on a |
2057 | /// particular byte. | |
2058 | /// | |
cc61c64b | 2059 | /// This struct is generally created by calling [`split`][split] on a |
c1a9b12d SL |
2060 | /// `BufRead`. Please see the documentation of `split()` for more details. |
2061 | /// | |
2062 | /// [split]: trait.BufRead.html#method.split | |
c34b1796 | 2063 | #[stable(feature = "rust1", since = "1.0.0")] |
32a655c1 | 2064 | #[derive(Debug)] |
85aaf69f SL |
2065 | pub struct Split<B> { |
2066 | buf: B, | |
2067 | delim: u8, | |
2068 | } | |
1a4d82fc | 2069 | |
c34b1796 | 2070 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
2071 | impl<B: BufRead> Iterator for Split<B> { |
2072 | type Item = Result<Vec<u8>>; | |
1a4d82fc | 2073 | |
85aaf69f SL |
2074 | fn next(&mut self) -> Option<Result<Vec<u8>>> { |
2075 | let mut buf = Vec::new(); | |
2076 | match self.buf.read_until(self.delim, &mut buf) { | |
c34b1796 AL |
2077 | Ok(0) => None, |
2078 | Ok(_n) => { | |
85aaf69f SL |
2079 | if buf[buf.len() - 1] == self.delim { |
2080 | buf.pop(); | |
2081 | } | |
2082 | Some(Ok(buf)) | |
2083 | } | |
2084 | Err(e) => Some(Err(e)) | |
1a4d82fc JJ |
2085 | } |
2086 | } | |
85aaf69f SL |
2087 | } |
2088 | ||
c1a9b12d | 2089 | /// An iterator over the lines of an instance of `BufRead`. |
85aaf69f | 2090 | /// |
cc61c64b | 2091 | /// This struct is generally created by calling [`lines`][lines] on a |
c1a9b12d SL |
2092 | /// `BufRead`. Please see the documentation of `lines()` for more details. |
2093 | /// | |
2094 | /// [lines]: trait.BufRead.html#method.lines | |
c34b1796 | 2095 | #[stable(feature = "rust1", since = "1.0.0")] |
32a655c1 | 2096 | #[derive(Debug)] |
85aaf69f SL |
2097 | pub struct Lines<B> { |
2098 | buf: B, | |
2099 | } | |
2100 | ||
c34b1796 | 2101 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f SL |
2102 | impl<B: BufRead> Iterator for Lines<B> { |
2103 | type Item = Result<String>; | |
1a4d82fc | 2104 | |
85aaf69f SL |
2105 | fn next(&mut self) -> Option<Result<String>> { |
2106 | let mut buf = String::new(); | |
2107 | match self.buf.read_line(&mut buf) { | |
c34b1796 AL |
2108 | Ok(0) => None, |
2109 | Ok(_n) => { | |
85aaf69f SL |
2110 | if buf.ends_with("\n") { |
2111 | buf.pop(); | |
e9174d1e SL |
2112 | if buf.ends_with("\r") { |
2113 | buf.pop(); | |
2114 | } | |
1a4d82fc | 2115 | } |
85aaf69f | 2116 | Some(Ok(buf)) |
1a4d82fc | 2117 | } |
85aaf69f | 2118 | Err(e) => Some(Err(e)) |
1a4d82fc JJ |
2119 | } |
2120 | } | |
85aaf69f SL |
2121 | } |
2122 | ||
2123 | #[cfg(test)] | |
2124 | mod tests { | |
85aaf69f | 2125 | use io::prelude::*; |
c34b1796 | 2126 | use io; |
85aaf69f | 2127 | use super::Cursor; |
c1a9b12d SL |
2128 | use test; |
2129 | use super::repeat; | |
1a4d82fc JJ |
2130 | |
2131 | #[test] | |
c30ab7b3 | 2132 | #[cfg_attr(target_os = "emscripten", ignore)] |
85aaf69f | 2133 | fn read_until() { |
c34b1796 | 2134 | let mut buf = Cursor::new(&b"12"[..]); |
85aaf69f | 2135 | let mut v = Vec::new(); |
c34b1796 | 2136 | assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2); |
85aaf69f SL |
2137 | assert_eq!(v, b"12"); |
2138 | ||
c34b1796 | 2139 | let mut buf = Cursor::new(&b"1233"[..]); |
85aaf69f | 2140 | let mut v = Vec::new(); |
c34b1796 | 2141 | assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3); |
85aaf69f SL |
2142 | assert_eq!(v, b"123"); |
2143 | v.truncate(0); | |
c34b1796 | 2144 | assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1); |
85aaf69f SL |
2145 | assert_eq!(v, b"3"); |
2146 | v.truncate(0); | |
c34b1796 | 2147 | assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0); |
85aaf69f | 2148 | assert_eq!(v, []); |
1a4d82fc JJ |
2149 | } |
2150 | ||
2151 | #[test] | |
85aaf69f | 2152 | fn split() { |
c34b1796 | 2153 | let buf = Cursor::new(&b"12"[..]); |
85aaf69f | 2154 | let mut s = buf.split(b'3'); |
c34b1796 AL |
2155 | assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']); |
2156 | assert!(s.next().is_none()); | |
1a4d82fc | 2157 | |
c34b1796 | 2158 | let buf = Cursor::new(&b"1233"[..]); |
85aaf69f | 2159 | let mut s = buf.split(b'3'); |
c34b1796 AL |
2160 | assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']); |
2161 | assert_eq!(s.next().unwrap().unwrap(), vec![]); | |
2162 | assert!(s.next().is_none()); | |
85aaf69f | 2163 | } |
1a4d82fc | 2164 | |
85aaf69f SL |
2165 | #[test] |
2166 | fn read_line() { | |
c34b1796 | 2167 | let mut buf = Cursor::new(&b"12"[..]); |
85aaf69f | 2168 | let mut v = String::new(); |
c34b1796 | 2169 | assert_eq!(buf.read_line(&mut v).unwrap(), 2); |
85aaf69f SL |
2170 | assert_eq!(v, "12"); |
2171 | ||
c34b1796 | 2172 | let mut buf = Cursor::new(&b"12\n\n"[..]); |
85aaf69f | 2173 | let mut v = String::new(); |
c34b1796 | 2174 | assert_eq!(buf.read_line(&mut v).unwrap(), 3); |
85aaf69f SL |
2175 | assert_eq!(v, "12\n"); |
2176 | v.truncate(0); | |
c34b1796 | 2177 | assert_eq!(buf.read_line(&mut v).unwrap(), 1); |
85aaf69f SL |
2178 | assert_eq!(v, "\n"); |
2179 | v.truncate(0); | |
c34b1796 | 2180 | assert_eq!(buf.read_line(&mut v).unwrap(), 0); |
85aaf69f SL |
2181 | assert_eq!(v, ""); |
2182 | } | |
1a4d82fc | 2183 | |
85aaf69f SL |
2184 | #[test] |
2185 | fn lines() { | |
e9174d1e | 2186 | let buf = Cursor::new(&b"12\r"[..]); |
85aaf69f | 2187 | let mut s = buf.lines(); |
e9174d1e | 2188 | assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string()); |
c34b1796 | 2189 | assert!(s.next().is_none()); |
1a4d82fc | 2190 | |
e9174d1e | 2191 | let buf = Cursor::new(&b"12\r\n\n"[..]); |
85aaf69f | 2192 | let mut s = buf.lines(); |
c34b1796 AL |
2193 | assert_eq!(s.next().unwrap().unwrap(), "12".to_string()); |
2194 | assert_eq!(s.next().unwrap().unwrap(), "".to_string()); | |
2195 | assert!(s.next().is_none()); | |
1a4d82fc JJ |
2196 | } |
2197 | ||
2198 | #[test] | |
85aaf69f | 2199 | fn read_to_end() { |
c34b1796 | 2200 | let mut c = Cursor::new(&b""[..]); |
85aaf69f | 2201 | let mut v = Vec::new(); |
c34b1796 | 2202 | assert_eq!(c.read_to_end(&mut v).unwrap(), 0); |
85aaf69f SL |
2203 | assert_eq!(v, []); |
2204 | ||
c34b1796 | 2205 | let mut c = Cursor::new(&b"1"[..]); |
85aaf69f | 2206 | let mut v = Vec::new(); |
c34b1796 | 2207 | assert_eq!(c.read_to_end(&mut v).unwrap(), 1); |
85aaf69f | 2208 | assert_eq!(v, b"1"); |
c1a9b12d SL |
2209 | |
2210 | let cap = 1024 * 1024; | |
2211 | let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>(); | |
2212 | let mut v = Vec::new(); | |
2213 | let (a, b) = data.split_at(data.len() / 2); | |
2214 | assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len()); | |
2215 | assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len()); | |
2216 | assert_eq!(v, data); | |
1a4d82fc JJ |
2217 | } |
2218 | ||
85aaf69f SL |
2219 | #[test] |
2220 | fn read_to_string() { | |
c34b1796 | 2221 | let mut c = Cursor::new(&b""[..]); |
85aaf69f | 2222 | let mut v = String::new(); |
c34b1796 | 2223 | assert_eq!(c.read_to_string(&mut v).unwrap(), 0); |
85aaf69f SL |
2224 | assert_eq!(v, ""); |
2225 | ||
c34b1796 | 2226 | let mut c = Cursor::new(&b"1"[..]); |
85aaf69f | 2227 | let mut v = String::new(); |
c34b1796 | 2228 | assert_eq!(c.read_to_string(&mut v).unwrap(), 1); |
85aaf69f SL |
2229 | assert_eq!(v, "1"); |
2230 | ||
c34b1796 | 2231 | let mut c = Cursor::new(&b"\xff"[..]); |
85aaf69f SL |
2232 | let mut v = String::new(); |
2233 | assert!(c.read_to_string(&mut v).is_err()); | |
1a4d82fc | 2234 | } |
c34b1796 | 2235 | |
e9174d1e SL |
2236 | #[test] |
2237 | fn read_exact() { | |
2238 | let mut buf = [0; 4]; | |
2239 | ||
2240 | let mut c = Cursor::new(&b""[..]); | |
2241 | assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), | |
92a42be0 | 2242 | io::ErrorKind::UnexpectedEof); |
e9174d1e SL |
2243 | |
2244 | let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..])); | |
2245 | c.read_exact(&mut buf).unwrap(); | |
2246 | assert_eq!(&buf, b"1234"); | |
2247 | c.read_exact(&mut buf).unwrap(); | |
2248 | assert_eq!(&buf, b"5678"); | |
2249 | assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), | |
92a42be0 | 2250 | io::ErrorKind::UnexpectedEof); |
e9174d1e SL |
2251 | } |
2252 | ||
2253 | #[test] | |
2254 | fn read_exact_slice() { | |
2255 | let mut buf = [0; 4]; | |
2256 | ||
2257 | let mut c = &b""[..]; | |
2258 | assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), | |
92a42be0 | 2259 | io::ErrorKind::UnexpectedEof); |
e9174d1e SL |
2260 | |
2261 | let mut c = &b"123"[..]; | |
2262 | assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), | |
92a42be0 | 2263 | io::ErrorKind::UnexpectedEof); |
e9174d1e SL |
2264 | // make sure the optimized (early returning) method is being used |
2265 | assert_eq!(&buf, &[0; 4]); | |
2266 | ||
2267 | let mut c = &b"1234"[..]; | |
2268 | c.read_exact(&mut buf).unwrap(); | |
2269 | assert_eq!(&buf, b"1234"); | |
2270 | ||
2271 | let mut c = &b"56789"[..]; | |
2272 | c.read_exact(&mut buf).unwrap(); | |
2273 | assert_eq!(&buf, b"5678"); | |
2274 | assert_eq!(c, b"9"); | |
2275 | } | |
2276 | ||
c34b1796 AL |
2277 | #[test] |
2278 | fn take_eof() { | |
2279 | struct R; | |
2280 | ||
2281 | impl Read for R { | |
2282 | fn read(&mut self, _: &mut [u8]) -> io::Result<usize> { | |
2283 | Err(io::Error::new(io::ErrorKind::Other, "")) | |
2284 | } | |
2285 | } | |
a7813a04 XL |
2286 | impl BufRead for R { |
2287 | fn fill_buf(&mut self) -> io::Result<&[u8]> { | |
2288 | Err(io::Error::new(io::ErrorKind::Other, "")) | |
2289 | } | |
2290 | fn consume(&mut self, _amt: usize) { } | |
2291 | } | |
c34b1796 AL |
2292 | |
2293 | let mut buf = [0; 1]; | |
2294 | assert_eq!(0, R.take(0).read(&mut buf).unwrap()); | |
a7813a04 | 2295 | assert_eq!(b"", R.take(0).fill_buf().unwrap()); |
c34b1796 | 2296 | } |
c1a9b12d | 2297 | |
54a0048b SL |
2298 | fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) { |
2299 | let mut cat = Vec::new(); | |
2300 | loop { | |
2301 | let consume = { | |
2302 | let buf1 = br1.fill_buf().unwrap(); | |
2303 | let buf2 = br2.fill_buf().unwrap(); | |
2304 | let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() }; | |
2305 | assert_eq!(buf1[..minlen], buf2[..minlen]); | |
2306 | cat.extend_from_slice(&buf1[..minlen]); | |
2307 | minlen | |
2308 | }; | |
2309 | if consume == 0 { | |
2310 | break; | |
2311 | } | |
2312 | br1.consume(consume); | |
2313 | br2.consume(consume); | |
2314 | } | |
2315 | assert_eq!(br1.fill_buf().unwrap().len(), 0); | |
2316 | assert_eq!(br2.fill_buf().unwrap().len(), 0); | |
2317 | assert_eq!(&cat[..], &exp[..]) | |
2318 | } | |
2319 | ||
2320 | #[test] | |
2321 | fn chain_bufread() { | |
2322 | let testdata = b"ABCDEFGHIJKL"; | |
2323 | let chain1 = (&testdata[..3]).chain(&testdata[3..6]) | |
2324 | .chain(&testdata[6..9]) | |
2325 | .chain(&testdata[9..]); | |
2326 | let chain2 = (&testdata[..4]).chain(&testdata[4..8]) | |
2327 | .chain(&testdata[8..]); | |
2328 | cmp_bufread(chain1, chain2, &testdata[..]); | |
2329 | } | |
2330 | ||
c30ab7b3 SL |
2331 | #[test] |
2332 | fn chain_zero_length_read_is_not_eof() { | |
2333 | let a = b"A"; | |
2334 | let b = b"B"; | |
2335 | let mut s = String::new(); | |
2336 | let mut chain = (&a[..]).chain(&b[..]); | |
2337 | chain.read(&mut []).unwrap(); | |
2338 | chain.read_to_string(&mut s).unwrap(); | |
2339 | assert_eq!("AB", s); | |
2340 | } | |
2341 | ||
c1a9b12d | 2342 | #[bench] |
c30ab7b3 | 2343 | #[cfg_attr(target_os = "emscripten", ignore)] |
c1a9b12d SL |
2344 | fn bench_read_to_end(b: &mut test::Bencher) { |
2345 | b.iter(|| { | |
2346 | let mut lr = repeat(1).take(10000000); | |
2347 | let mut vec = Vec::with_capacity(1024); | |
9cc50fc6 | 2348 | super::read_to_end(&mut lr, &mut vec) |
c1a9b12d SL |
2349 | }); |
2350 | } | |
1a4d82fc | 2351 | } |