Struct futures::io::Cursor [−][src]
pub struct Cursor<T> { /* fields omitted */ }
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]
>
.
Implementations
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());
Consumes this cursor, returning the underlying value.
Examples
use futures::io::Cursor; let buff = Cursor::new(Vec::new()); let vec = buff.into_inner();
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();
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();
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);
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
Attempt to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more
Auto Trait Implementations
impl<T> RefUnwindSafe for Cursor<T> where
T: RefUnwindSafe,
impl<T> UnwindSafe for Cursor<T> where
T: UnwindSafe,
Blanket Implementations
Creates a future which will wait for a non-empty buffer to be available from this I/O object or EOF to be reached. Read more
A convenience for calling AsyncBufRead::consume
on Unpin
IO types. Read more
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
. Read more
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
. Read more
Returns a stream over the lines of this reader.
This method is the async equivalent to BufRead::lines
. Read more
Creates an adaptor which will chain this stream with another. Read more
Tries to read some bytes directly into the given buf
in asynchronous
manner, returning a future type. Read more
fn read_vectored(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>]
) -> ReadVectored<'a, Self>ⓘNotable traits for ReadVectored<'_, R>
impl<'_, R> Future for ReadVectored<'_, R> where
R: AsyncRead + Unpin + ?Sized, type Output = Result<usize, Error>;
where
Self: Unpin,
fn read_vectored(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>]
) -> ReadVectored<'a, Self>ⓘNotable traits for ReadVectored<'_, R>
impl<'_, R> Future for ReadVectored<'_, R> where
R: AsyncRead + Unpin + ?Sized, type Output = Result<usize, Error>;
where
Self: Unpin,
Creates a future which will read from the AsyncRead
into bufs
using vectored
IO operations. Read more
Creates a future which will read exactly enough bytes to fill buf
,
returning an error if end of file (EOF) is hit sooner. Read more
Creates a future which will read all the bytes from this AsyncRead
. Read more
fn read_to_string(&'a mut self, buf: &'a mut String) -> ReadToString<'a, Self>ⓘNotable traits for ReadToString<'_, A>
impl<'_, A> Future for ReadToString<'_, A> where
A: AsyncRead + Unpin + ?Sized, type Output = Result<usize, Error>;
where
Self: Unpin,
fn read_to_string(&'a mut self, buf: &'a mut String) -> ReadToString<'a, Self>ⓘNotable traits for ReadToString<'_, A>
impl<'_, A> Future for ReadToString<'_, A> where
A: AsyncRead + Unpin + ?Sized, type Output = Result<usize, Error>;
where
Self: Unpin,
Creates a future which will read all the bytes from this AsyncRead
. Read more
Helper method for splitting this read/write object into two halves. Read more
Creates an AsyncRead adapter which will read at most limit
bytes
from the underlying reader. Read more
Wraps an AsyncRead
in a compatibility wrapper that allows it to be
used as a futures 0.1 / tokio-io 0.1 AsyncRead
. If the wrapped type
implements AsyncWrite
as well, the result will also implement the
futures 0.1 / tokio 0.1 AsyncWrite
trait. Read more
Creates a future which will entirely flush this AsyncWrite
. Read more
Creates a future which will entirely close this AsyncWrite
.
Creates a future which will write bytes from buf
into the object. Read more
fn write_vectored(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectored<'a, Self>ⓘNotable traits for WriteVectored<'_, W>
impl<'_, W> Future for WriteVectored<'_, W> where
W: AsyncWrite + Unpin + ?Sized, type Output = Result<usize, Error>;
where
Self: Unpin,
fn write_vectored(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectored<'a, Self>ⓘNotable traits for WriteVectored<'_, W>
impl<'_, W> Future for WriteVectored<'_, W> where
W: AsyncWrite + Unpin + ?Sized, type Output = Result<usize, Error>;
where
Self: Unpin,
Creates a future which will write bytes from bufs
into the object using vectored
IO operations. Read more
Write data into this object. Read more
fn write_all_vectored(
&'a mut self,
bufs: &'a mut [IoSlice<'a>]
) -> WriteAllVectored<'a, Self>ⓘNotable traits for WriteAllVectored<'_, W>
impl<'_, W> Future for WriteAllVectored<'_, W> where
W: AsyncWrite + Unpin + ?Sized, type Output = Result<(), Error>;
where
Self: Unpin,
fn write_all_vectored(
&'a mut self,
bufs: &'a mut [IoSlice<'a>]
) -> WriteAllVectored<'a, Self>ⓘNotable traits for WriteAllVectored<'_, W>
impl<'_, W> Future for WriteAllVectored<'_, W> where
W: AsyncWrite + Unpin + ?Sized, type Output = Result<(), Error>;
where
Self: Unpin,
Attempts to write multiple buffers into this writer. Read more
Wraps an AsyncWrite
in a compatibility wrapper that allows it to be
used as a futures 0.1 / tokio-io 0.1 AsyncWrite
.
Requires the io-compat
feature to enable. Read more
Mutably borrows from an owned value. Read more