Struct futures_util::io::Cursor
source · pub struct Cursor<T> {
inner: Cursor<T>,
}
Expand description
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.
This library implements some I/O traits on various types which
are commonly used as a buffer, like Cursor<
Vec
<u8>>
and
Cursor<
&[u8]
>
.
Fields§
§inner: Cursor<T>
Implementations§
source§impl<T> Cursor<T>
impl<T> Cursor<T>
sourcepub fn new(inner: T) -> Self
pub fn new(inner: T) -> Self
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());
sourcepub fn into_inner(self) -> T
pub fn into_inner(self) -> T
Consumes this cursor, returning the underlying value.
§Examples
use futures::io::Cursor;
let buff = Cursor::new(Vec::new());
let vec = buff.into_inner();
sourcepub fn get_ref(&self) -> &T
pub fn get_ref(&self) -> &T
Gets a reference to the underlying value in this cursor.
§Examples
use futures::io::Cursor;
let buff = Cursor::new(Vec::new());
let reference = buff.get_ref();
sourcepub fn get_mut(&mut self) -> &mut T
pub fn get_mut(&mut self) -> &mut T
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());
let reference = buff.get_mut();
sourcepub fn position(&self) -> u64
pub fn position(&self) -> u64
Returns the current position of this cursor.
§Examples
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);
sourcepub fn set_position(&mut self, pos: u64)
pub fn set_position(&mut self, pos: u64)
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);
Trait Implementations§
source§impl<T> AsyncBufRead for Cursor<T>
impl<T> AsyncBufRead for Cursor<T>
source§impl<T: AsRef<[u8]> + Unpin> AsyncRead for Cursor<T>
impl<T: AsRef<[u8]> + Unpin> AsyncRead for Cursor<T>
source§impl AsyncWrite for Cursor<&mut [u8]>
impl AsyncWrite for Cursor<&mut [u8]>
source§fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize>>
fn poll_write( self: Pin<&mut Self>, _: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>
buf
into the object. Read moresource§fn poll_write_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<Result<usize>>
fn poll_write_vectored( self: Pin<&mut Self>, _: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize>>
bufs
into the object using vectored
IO operations. Read moresource§impl AsyncWrite for Cursor<&mut Vec<u8>>
impl AsyncWrite for Cursor<&mut Vec<u8>>
source§fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize>>
fn poll_write( self: Pin<&mut Self>, _: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>
buf
into the object. Read moresource§fn poll_write_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<Result<usize>>
fn poll_write_vectored( self: Pin<&mut Self>, _: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize>>
bufs
into the object using vectored
IO operations. Read moresource§impl AsyncWrite for Cursor<Box<[u8]>>
impl AsyncWrite for Cursor<Box<[u8]>>
source§fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize>>
fn poll_write( self: Pin<&mut Self>, _: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>
buf
into the object. Read moresource§fn poll_write_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<Result<usize>>
fn poll_write_vectored( self: Pin<&mut Self>, _: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize>>
bufs
into the object using vectored
IO operations. Read moresource§impl AsyncWrite for Cursor<Vec<u8>>
impl AsyncWrite for Cursor<Vec<u8>>
source§fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize>>
fn poll_write( self: Pin<&mut Self>, _: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>
buf
into the object. Read moresource§fn poll_write_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<Result<usize>>
fn poll_write_vectored( self: Pin<&mut Self>, _: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize>>
bufs
into the object using vectored
IO operations. Read moreAuto Trait Implementations§
impl<T> Freeze for Cursor<T>where
T: Freeze,
impl<T> RefUnwindSafe for Cursor<T>where
T: RefUnwindSafe,
impl<T> Send for Cursor<T>where
T: Send,
impl<T> Sync for Cursor<T>where
T: Sync,
impl<T> Unpin for Cursor<T>where
T: Unpin,
impl<T> UnwindSafe for Cursor<T>where
T: UnwindSafe,
Blanket Implementations§
source§impl<R> AsyncBufReadExt for Rwhere
R: AsyncBufRead + ?Sized,
impl<R> AsyncBufReadExt for Rwhere
R: AsyncBufRead + ?Sized,
source§fn fill_buf(&mut self) -> FillBuf<'_, Self> ⓘwhere
Self: Unpin,
fn fill_buf(&mut self) -> FillBuf<'_, Self> ⓘwhere
Self: Unpin,
source§fn consume_unpin(&mut self, amt: usize)where
Self: Unpin,
fn consume_unpin(&mut self, amt: usize)where
Self: Unpin,
source§fn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>,
) -> ReadUntil<'a, Self> ⓘwhere
Self: Unpin,
fn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>,
) -> ReadUntil<'a, Self> ⓘwhere
Self: Unpin,
buf
until the delimiter byte
or EOF is reached.
This method is the async equivalent to BufRead::read_until
. Read moresource§fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self> ⓘwhere
Self: Unpin,
fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self> ⓘwhere
Self: Unpin,
buf
until a newline (the 0xA byte) or EOF is reached,
This method is the async equivalent to BufRead::read_line
. Read moresource§impl<R> AsyncReadExt for R
impl<R> AsyncReadExt for R
source§fn chain<R>(self, next: R) -> Chain<Self, R>
fn chain<R>(self, next: R) -> Chain<Self, R>
source§fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self> ⓘwhere
Self: Unpin,
fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self> ⓘwhere
Self: Unpin,
buf
in asynchronous
manner, returning a future type. Read moresource§fn read_vectored<'a>(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>],
) -> ReadVectored<'a, Self> ⓘwhere
Self: Unpin,
fn read_vectored<'a>(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>],
) -> ReadVectored<'a, Self> ⓘwhere
Self: Unpin,
AsyncRead
into bufs
using vectored
IO operations. Read moresource§fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self> ⓘwhere
Self: Unpin,
fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self> ⓘwhere
Self: Unpin,
buf
,
returning an error if end of file (EOF) is hit sooner. Read moresource§fn read_to_end<'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self> ⓘwhere
Self: Unpin,
fn read_to_end<'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self> ⓘwhere
Self: Unpin,
AsyncRead
. Read moresource§fn read_to_string<'a>(
&'a mut self,
buf: &'a mut String,
) -> ReadToString<'a, Self> ⓘwhere
Self: Unpin,
fn read_to_string<'a>(
&'a mut self,
buf: &'a mut String,
) -> ReadToString<'a, Self> ⓘwhere
Self: Unpin,
AsyncRead
. Read moresource§impl<S> AsyncSeekExt for S
impl<S> AsyncSeekExt for S
source§impl<W> AsyncWriteExt for Wwhere
W: AsyncWrite + ?Sized,
impl<W> AsyncWriteExt for Wwhere
W: AsyncWrite + ?Sized,
source§fn flush(&mut self) -> Flush<'_, Self> ⓘwhere
Self: Unpin,
fn flush(&mut self) -> Flush<'_, Self> ⓘwhere
Self: Unpin,
AsyncWrite
. Read moresource§fn close(&mut self) -> Close<'_, Self> ⓘwhere
Self: Unpin,
fn close(&mut self) -> Close<'_, Self> ⓘwhere
Self: Unpin,
AsyncWrite
.source§fn write<'a>(&'a mut self, buf: &'a [u8]) -> Write<'a, Self> ⓘwhere
Self: Unpin,
fn write<'a>(&'a mut self, buf: &'a [u8]) -> Write<'a, Self> ⓘwhere
Self: Unpin,
buf
into the object. Read moresource§fn write_vectored<'a>(
&'a mut self,
bufs: &'a [IoSlice<'a>],
) -> WriteVectored<'a, Self> ⓘwhere
Self: Unpin,
fn write_vectored<'a>(
&'a mut self,
bufs: &'a [IoSlice<'a>],
) -> WriteVectored<'a, Self> ⓘwhere
Self: Unpin,
bufs
into the object using vectored
IO operations. Read moresource§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)