Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
14 changed files
with
284 additions
and
104 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,238 @@ | ||
use futures_core::task::{Context, Poll}; | ||
#[cfg(feature = "read_initializer")] | ||
use futures_io::Initializer; | ||
use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSlice, IoSliceMut, SeekFrom}; | ||
use std::io; | ||
use std::pin::Pin; | ||
|
||
/// A `Cursor` wraps an in-memory buffer and provides it with a | ||
/// [`AsyncSeek`] implementation. | ||
/// | ||
/// `Cursor`s are used with in-memory buffers, anything implementing | ||
/// `AsRef<[u8]>`, to allow them to implement [`AsyncRead`] and/or [`AsyncWrite`], | ||
/// allowing these buffers to be used anywhere you might use a reader or writer | ||
/// that does actual I/O. | ||
/// | ||
/// The standard library implements some I/O traits on various types which | ||
/// are commonly used as a buffer, like `Cursor<`[`Vec`]`<u8>>` and | ||
/// `Cursor<`[`&[u8]`][bytes]`>`. | ||
/// | ||
/// [`AsyncSeek`]: trait.AsyncSeek.html | ||
/// [`AsyncRead`]: trait.AsyncRead.html | ||
/// [`AsyncWrite`]: trait.AsyncWrite.html | ||
/// [bytes]: https://doc.rust-lang.org/std/primitive.slice.html | ||
#[derive(Clone, Debug, Default)] | ||
pub struct Cursor<T> { | ||
inner: io::Cursor<T>, | ||
} | ||
|
||
impl<T> Cursor<T> { | ||
/// Creates a new cursor wrapping the provided underlying in-memory buffer. | ||
/// | ||
/// Cursor initial position is `0` even if underlying buffer (e.g., `Vec`) | ||
/// is not empty. So writing to cursor starts with overwriting `Vec` | ||
/// content, not with appending to it. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// use futures::io::Cursor; | ||
/// | ||
/// let buff = Cursor::new(Vec::new()); | ||
/// # fn force_inference(_: &Cursor<Vec<u8>>) {} | ||
/// # force_inference(&buff); | ||
/// ``` | ||
pub fn new(inner: T) -> Cursor<T> { | ||
Cursor { | ||
inner: io::Cursor::new(inner), | ||
} | ||
} | ||
|
||
/// Consumes this cursor, returning the underlying value. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// use futures::io::Cursor; | ||
/// | ||
/// let buff = Cursor::new(Vec::new()); | ||
/// # fn force_inference(_: &Cursor<Vec<u8>>) {} | ||
/// # force_inference(&buff); | ||
/// | ||
/// let vec = buff.into_inner(); | ||
/// ``` | ||
pub fn into_inner(self) -> T { | ||
self.inner.into_inner() | ||
} | ||
|
||
/// Gets a reference to the underlying value in this cursor. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// use futures::io::Cursor; | ||
/// | ||
/// let buff = Cursor::new(Vec::new()); | ||
/// # fn force_inference(_: &Cursor<Vec<u8>>) {} | ||
/// # force_inference(&buff); | ||
/// | ||
/// let reference = buff.get_ref(); | ||
/// ``` | ||
pub fn get_ref(&self) -> &T { | ||
self.inner.get_ref() | ||
} | ||
|
||
/// Gets a mutable reference to the underlying value in this cursor. | ||
/// | ||
/// Care should be taken to avoid modifying the internal I/O state of the | ||
/// underlying value as it may corrupt this cursor's position. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// use futures::io::Cursor; | ||
/// | ||
/// let mut buff = Cursor::new(Vec::new()); | ||
/// # fn force_inference(_: &Cursor<Vec<u8>>) {} | ||
/// # force_inference(&buff); | ||
/// | ||
/// let reference = buff.get_mut(); | ||
/// ``` | ||
pub fn get_mut(&mut self) -> &mut T { | ||
self.inner.get_mut() | ||
} | ||
|
||
/// Returns the current position of this cursor. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// # futures::executor::block_on(async { | ||
/// use futures::io::{AsyncSeekExt, Cursor, SeekFrom}; | ||
/// | ||
/// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]); | ||
/// | ||
/// assert_eq!(buff.position(), 0); | ||
/// | ||
/// buff.seek(SeekFrom::Current(2)).await?; | ||
/// assert_eq!(buff.position(), 2); | ||
/// | ||
/// buff.seek(SeekFrom::Current(-1)).await?; | ||
/// assert_eq!(buff.position(), 1); | ||
/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); | ||
/// ``` | ||
pub fn position(&self) -> u64 { | ||
self.inner.position() | ||
} | ||
|
||
/// Sets the position of this cursor. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// use futures::io::Cursor; | ||
/// | ||
/// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]); | ||
/// | ||
/// assert_eq!(buff.position(), 0); | ||
/// | ||
/// buff.set_position(2); | ||
/// assert_eq!(buff.position(), 2); | ||
/// | ||
/// buff.set_position(4); | ||
/// assert_eq!(buff.position(), 4); | ||
/// ``` | ||
pub fn set_position(&mut self, pos: u64) { | ||
self.inner.set_position(pos) | ||
} | ||
} | ||
|
||
impl<T> AsyncSeek for Cursor<T> | ||
where | ||
T: AsRef<[u8]> + Unpin, | ||
{ | ||
fn poll_seek( | ||
mut self: Pin<&mut Self>, | ||
_: &mut Context<'_>, | ||
pos: SeekFrom, | ||
) -> Poll<io::Result<u64>> { | ||
Poll::Ready(io::Seek::seek(&mut self.inner, pos)) | ||
} | ||
} | ||
|
||
impl<T: AsRef<[u8]> + Unpin> AsyncRead for Cursor<T> { | ||
#[cfg(feature = "read_initializer")] | ||
#[inline] | ||
unsafe fn initializer(&self) -> Initializer { | ||
io::Read::initializer(&self.inner) | ||
} | ||
|
||
fn poll_read( | ||
mut self: Pin<&mut Self>, | ||
_cx: &mut Context<'_>, | ||
buf: &mut [u8], | ||
) -> Poll<io::Result<usize>> { | ||
Poll::Ready(io::Read::read(&mut self.inner, buf)) | ||
} | ||
|
||
fn poll_read_vectored( | ||
mut self: Pin<&mut Self>, | ||
_: &mut Context<'_>, | ||
bufs: &mut [IoSliceMut<'_>], | ||
) -> Poll<io::Result<usize>> { | ||
Poll::Ready(io::Read::read_vectored(&mut self.inner, bufs)) | ||
} | ||
} | ||
|
||
impl<T> AsyncBufRead for Cursor<T> | ||
where | ||
T: AsRef<[u8]> + Unpin, | ||
{ | ||
fn poll_fill_buf(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { | ||
Poll::Ready(io::BufRead::fill_buf(&mut self.get_mut().inner)) | ||
} | ||
|
||
fn consume(mut self: Pin<&mut Self>, amt: usize) { | ||
io::BufRead::consume(&mut self.inner, amt) | ||
} | ||
} | ||
|
||
macro_rules! delegate_async_write_to_stdio { | ||
() => { | ||
fn poll_write(mut self: Pin<&mut Self>, _: &mut Context<'_>, buf: &[u8]) | ||
-> Poll<io::Result<usize>> | ||
{ | ||
Poll::Ready(io::Write::write(&mut self.inner, buf)) | ||
} | ||
|
||
fn poll_write_vectored(mut self: Pin<&mut Self>, _: &mut Context<'_>, bufs: &[IoSlice<'_>]) | ||
-> Poll<io::Result<usize>> | ||
{ | ||
Poll::Ready(io::Write::write_vectored(&mut self.inner, bufs)) | ||
} | ||
|
||
fn poll_flush(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> { | ||
Poll::Ready(io::Write::flush(&mut self.inner)) | ||
} | ||
|
||
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { | ||
self.poll_flush(cx) | ||
} | ||
} | ||
} | ||
|
||
impl AsyncWrite for Cursor<&mut [u8]> { | ||
delegate_async_write_to_stdio!(); | ||
} | ||
|
||
impl AsyncWrite for Cursor<&mut Vec<u8>> { | ||
delegate_async_write_to_stdio!(); | ||
} | ||
|
||
impl AsyncWrite for Cursor<Vec<u8>> { | ||
delegate_async_write_to_stdio!(); | ||
} | ||
|
||
impl AsyncWrite for Cursor<Box<[u8]>> { | ||
delegate_async_write_to_stdio!(); | ||
} |
Oops, something went wrong.