diff options
Diffstat (limited to 'tokio/src/io/util/async_buf_read_ext.rs')
-rw-r--r-- | tokio/src/io/util/async_buf_read_ext.rs | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/tokio/src/io/util/async_buf_read_ext.rs b/tokio/src/io/util/async_buf_read_ext.rs new file mode 100644 index 00000000..7567d72e --- /dev/null +++ b/tokio/src/io/util/async_buf_read_ext.rs @@ -0,0 +1,122 @@ +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; + +/// An extension trait which adds utility methods to `AsyncBufRead` types. +pub trait AsyncBufReadExt: AsyncBufRead { + /// Creates a future which will read all the bytes associated with this I/O + /// object into `buf` until the delimiter `byte` or EOF is reached. + /// This method is the async equivalent to [`BufRead::read_until`](std::io::BufRead::read_until). + /// + /// 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`. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + 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) + } + + /// Creates a future which will read all the bytes associated with this I/O + /// object into `buf` until a newline (the 0xA byte) or EOF is reached, + /// This method is the async equivalent to [`BufRead::read_line`](std::io::BufRead::read_line). + /// + /// 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`. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + /// + /// # 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 + 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`]. + /// + /// [`AsyncBufReadExt::read_line`]: AsyncBufReadExt::read_line + fn lines(self) -> Lines<Self> + where + Self: Sized, + { + lines(self) + } +} + +impl<R: AsyncBufRead + ?Sized> AsyncBufReadExt for R {} |