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use crate::io::util::lines::{lines, Lines}; use crate::io::util::read_line::{read_line, ReadLine}; use crate::io::util::read_until::{read_until, ReadUntil}; use crate::io::util::split::{split, Split}; use crate::io::AsyncBufRead; cfg_io_util! { /// An extension trait which adds utility methods to [`AsyncBufRead`] types. /// /// [`AsyncBufRead`]: crate::io::AsyncBufRead pub trait AsyncBufReadExt: AsyncBufRead { /// Reads all bytes into `buf` until the delimiter `byte` or EOF is reached. /// /// Equivalent to: /// /// ```ignore /// async fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize>; /// ``` /// /// This function will read bytes from the underlying stream until the /// delimiter or EOF is found. Once found, all bytes up to, and including, /// the delimiter (if found) will be appended to `buf`. /// /// If successful, this function will return the total number of bytes read. /// /// # Errors /// /// This function will ignore all instances of [`ErrorKind::Interrupted`] and /// will otherwise return any errors returned by [`fill_buf`]. /// /// If an I/O error is encountered then all bytes read so far will be /// present in `buf` and its length will have been adjusted appropriately. /// /// [`fill_buf`]: AsyncBufRead::poll_fill_buf /// [`ErrorKind::Interrupted`]: std::io::ErrorKind::Interrupted /// /// # Examples /// /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In /// this example, we use [`Cursor`] to read all the bytes in a byte slice /// in hyphen delimited segments: /// /// [`Cursor`]: std::io::Cursor /// /// ``` /// use tokio::io::AsyncBufReadExt; /// /// use std::io::Cursor; /// /// #[tokio::main] /// async fn main() { /// let mut cursor = Cursor::new(b"lorem-ipsum"); /// let mut buf = vec![]; /// /// // cursor is at 'l' /// let num_bytes = cursor.read_until(b'-', &mut buf) /// .await /// .expect("reading from cursor won't fail"); /// /// assert_eq!(num_bytes, 6); /// assert_eq!(buf, b"lorem-"); /// buf.clear(); /// /// // cursor is at 'i' /// let num_bytes = cursor.read_until(b'-', &mut buf) /// .await /// .expect("reading from cursor won't fail"); /// /// assert_eq!(num_bytes, 5); /// assert_eq!(buf, b"ipsum"); /// buf.clear(); /// /// // cursor is at EOF /// let num_bytes = cursor.read_until(b'-', &mut buf) /// .await /// .expect("reading from cursor won't fail"); /// assert_eq!(num_bytes, 0); /// assert_eq!(buf, b""); /// } /// ``` fn read_until<'a>(&'a mut self, byte: u8, buf: &'a mut Vec<u8>) -> ReadUntil<'a, Self> where Self: Unpin, { read_until(self, byte, buf) } /// Reads all bytes until a newline (the 0xA byte) is reached, and append /// them to the provided buffer. /// /// Equivalent to: /// /// ```ignore /// async fn read_line(&mut self, buf: &mut String) -> io::Result<usize>; /// ``` /// /// This function will read bytes from the underlying stream until the /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes /// up to, and including, the delimiter (if found) will be appended to /// `buf`. /// /// If successful, this function will return the total number of bytes read. /// /// If this function returns `Ok(0)`, the stream has reached EOF. /// /// # Errors /// /// This function has the same error semantics as [`read_until`] and will /// also return an error if the read bytes are not valid UTF-8. If an I/O /// error is encountered then `buf` may contain some bytes already read in /// the event that all data read so far was valid UTF-8. /// /// [`read_until`]: AsyncBufReadExt::read_until /// /// # Examples /// /// [`std::io::Cursor`][`Cursor`] is a type that implements /// `AsyncBufRead`. In this example, we use [`Cursor`] to read all the /// lines in a byte slice: /// /// [`Cursor`]: std::io::Cursor /// /// ``` /// use tokio::io::AsyncBufReadExt; /// /// use std::io::Cursor; /// /// #[tokio::main] /// async fn main() { /// let mut cursor = Cursor::new(b"foo\nbar"); /// let mut buf = String::new(); /// /// // cursor is at 'f' /// let num_bytes = cursor.read_line(&mut buf) /// .await /// .expect("reading from cursor won't fail"); /// /// assert_eq!(num_bytes, 4); /// assert_eq!(buf, "foo\n"); /// buf.clear(); /// /// // cursor is at 'b' /// let num_bytes = cursor.read_line(&mut buf) /// .await /// .expect("reading from cursor won't fail"); /// /// assert_eq!(num_bytes, 3); /// assert_eq!(buf, "bar"); /// buf.clear(); /// /// // cursor is at EOF /// let num_bytes = cursor.read_line(&mut buf) /// .await /// .expect("reading from cursor won't fail"); /// /// assert_eq!(num_bytes, 0); /// assert_eq!(buf, ""); /// } /// ``` fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self> where Self: Unpin, { read_line(self, buf) } /// Returns a stream of the contents of this reader split on the byte /// `byte`. /// /// This method is the asynchronous equivalent to /// [`BufRead::split`](std::io::BufRead::split). /// /// The stream returned from this function will yield instances of /// [`io::Result`]`<`[`Vec<u8>`]`>`. Each vector returned will *not* have /// the delimiter byte at the end. /// /// [`io::Result`]: std::io::Result /// [`Vec<u8>`]: std::vec::Vec /// /// # Errors /// /// Each item of the stream has the same error semantics as /// [`AsyncBufReadExt::read_until`](AsyncBufReadExt::read_until). /// /// # Examples /// /// ``` /// # use tokio::io::AsyncBufRead; /// use tokio::io::AsyncBufReadExt; /// /// # async fn dox(my_buf_read: impl AsyncBufRead + Unpin) -> std::io::Result<()> { /// let mut segments = my_buf_read.split(b'f'); /// /// while let Some(segment) = segments.next_segment().await? { /// println!("length = {}", segment.len()) /// } /// # Ok(()) /// # } /// ``` fn split(self, byte: u8) -> Split<Self> where Self: Sized + Unpin, { split(self, byte) } /// Returns a stream over the lines of this reader. /// This method is the async equivalent to [`BufRead::lines`](std::io::BufRead::lines). /// /// The stream returned from this function will yield instances of /// [`io::Result`]`<`[`String`]`>`. Each string returned will *not* have a newline /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end. /// /// [`io::Result`]: std::io::Result /// [`String`]: String /// /// # Errors /// /// Each line of the stream has the same error semantics as [`AsyncBufReadExt::read_line`]. /// /// # Examples /// /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In /// this example, we use [`Cursor`] to iterate over all the lines in a byte /// slice. /// /// [`Cursor`]: std::io::Cursor /// /// ``` /// use tokio::io::AsyncBufReadExt; /// use tokio::stream::StreamExt; /// /// use std::io::Cursor; /// /// #[tokio::main] /// async fn main() { /// let cursor = Cursor::new(b"lorem\nipsum\r\ndolor"); /// /// let mut lines = cursor.lines().map(|res| res.unwrap()); /// /// assert_eq!(lines.next().await, Some(String::from("lorem"))); /// assert_eq!(lines.next().await, Some(String::from("ipsum"))); /// assert_eq!(lines.next().await, Some(String::from("dolor"))); /// assert_eq!(lines.next().await, None); /// } /// ``` /// /// [`AsyncBufReadExt::read_line`]: AsyncBufReadExt::read_line fn lines(self) -> Lines<Self> where Self: Sized, { lines(self) } } } impl<R: AsyncBufRead + ?Sized> AsyncBufReadExt for R {}