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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.

Cursors 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

impl<T> Cursor<T>[src]

pub fn new(inner: T) -> Cursor<T>[src]

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());

pub fn into_inner(self) -> T[src]

Consumes this cursor, returning the underlying value.

Examples

use futures::io::Cursor;

let buff = Cursor::new(Vec::new());

let vec = buff.into_inner();

pub fn get_ref(&self) -> &T[src]

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();

pub fn get_mut(&mut self) -> &mut T[src]

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();

pub fn position(&self) -> u64[src]

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);

pub fn set_position(&mut self, pos: u64)[src]

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

impl<T> AsyncBufRead for Cursor<T> where
    T: AsRef<[u8]> + Unpin, [src]

pub fn poll_fill_buf(
    self: Pin<&mut Cursor<T>>,
    &mut Context<'_>
) -> Poll<Result<&[u8], Error>>[src]

Attempt to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more

pub fn consume(self: Pin<&mut Cursor<T>>, amt: usize)[src]

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to poll_read. Read more

impl<T> AsyncRead for Cursor<T> where
    T: AsRef<[u8]> + Unpin, [src]

pub fn poll_read(
    self: Pin<&mut Cursor<T>>,
    _cx: &mut Context<'_>,
    buf: &mut [u8]
) -> Poll<Result<usize, Error>>[src]

Attempt to read from the AsyncRead into buf. Read more

pub fn poll_read_vectored(
    self: Pin<&mut Cursor<T>>,
    &mut Context<'_>,
    bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize, Error>>[src]

Attempt to read from the AsyncRead into bufs using vectored IO operations. Read more

unsafe fn initializer(&self) -> Initializer[src]

Determines if this AsyncReader can work with buffers of uninitialized memory. Read more

impl<T> AsyncSeek for Cursor<T> where
    T: AsRef<[u8]> + Unpin, [src]

pub fn poll_seek(
    self: Pin<&mut Cursor<T>>,
    &mut Context<'_>,
    pos: SeekFrom
) -> Poll<Result<u64, Error>>[src]

Attempt to seek to an offset, in bytes, in a stream. Read more

impl AsyncWrite for Cursor<Box<[u8], Global>>[src]

pub fn poll_write(
    self: Pin<&mut Cursor<Box<[u8], Global>>>,
    &mut Context<'_>,
    buf: &[u8]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from buf into the object. Read more

pub fn poll_write_vectored(
    self: Pin<&mut Cursor<Box<[u8], Global>>>,
    &mut Context<'_>,
    bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from bufs into the object using vectored IO operations. Read more

pub fn poll_flush(
    self: Pin<&mut Cursor<Box<[u8], Global>>>,
    &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

pub fn poll_close(
    self: Pin<&mut Cursor<Box<[u8], Global>>>,
    cx: &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to close the object. Read more

impl<'_> AsyncWrite for Cursor<&'_ mut Vec<u8, Global>>[src]

pub fn poll_write(
    self: Pin<&mut Cursor<&'_ mut Vec<u8, Global>>>,
    &mut Context<'_>,
    buf: &[u8]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from buf into the object. Read more

pub fn poll_write_vectored(
    self: Pin<&mut Cursor<&'_ mut Vec<u8, Global>>>,
    &mut Context<'_>,
    bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from bufs into the object using vectored IO operations. Read more

pub fn poll_flush(
    self: Pin<&mut Cursor<&'_ mut Vec<u8, Global>>>,
    &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

pub fn poll_close(
    self: Pin<&mut Cursor<&'_ mut Vec<u8, Global>>>,
    cx: &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to close the object. Read more

impl<'_> AsyncWrite for Cursor<&'_ mut [u8]>[src]

pub fn poll_write(
    self: Pin<&mut Cursor<&'_ mut [u8]>>,
    &mut Context<'_>,
    buf: &[u8]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from buf into the object. Read more

pub fn poll_write_vectored(
    self: Pin<&mut Cursor<&'_ mut [u8]>>,
    &mut Context<'_>,
    bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from bufs into the object using vectored IO operations. Read more

pub fn poll_flush(
    self: Pin<&mut Cursor<&'_ mut [u8]>>,
    &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

pub fn poll_close(
    self: Pin<&mut Cursor<&'_ mut [u8]>>,
    cx: &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to close the object. Read more

impl AsyncWrite for Cursor<Vec<u8, Global>>[src]

pub fn poll_write(
    self: Pin<&mut Cursor<Vec<u8, Global>>>,
    &mut Context<'_>,
    buf: &[u8]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from buf into the object. Read more

pub fn poll_write_vectored(
    self: Pin<&mut Cursor<Vec<u8, Global>>>,
    &mut Context<'_>,
    bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>[src]

Attempt to write bytes from bufs into the object using vectored IO operations. Read more

pub fn poll_flush(
    self: Pin<&mut Cursor<Vec<u8, Global>>>,
    &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

pub fn poll_close(
    self: Pin<&mut Cursor<Vec<u8, Global>>>,
    cx: &mut Context<'_>
) -> Poll<Result<(), Error>>[src]

Attempt to close the object. Read more

impl<T> Clone for Cursor<T> where
    T: Clone, [src]

pub fn clone(&self) -> Cursor<T>[src]

Returns a copy of the value. Read more

fn clone_from(&mut self, source: &Self)1.0.0[src]

Performs copy-assignment from source. Read more

impl<T> Debug for Cursor<T> where
    T: Debug, [src]

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>[src]

Formats the value using the given formatter. Read more

impl<T> Default for Cursor<T> where
    T: Default, [src]

pub fn default() -> Cursor<T>[src]

Returns the “default value” for a type. Read more

Auto Trait Implementations

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

impl<T> Any for T where
    T: 'static + ?Sized, [src]

pub fn type_id(&self) -> TypeId[src]

Gets the TypeId of self. Read more

impl<R> AsyncBufReadExt for R where
    R: AsyncBufRead + ?Sized, [src]

fn fill_buf(&mut self) -> FillBuf<'_, Self>ⓘ

Notable traits for FillBuf<'a, R>

impl<'a, R> Future for FillBuf<'a, R> where
    R: AsyncBufRead + Unpin + ?Sized,  type Output = Result<&'a [u8], Error>;
 where
    Self: Unpin, [src]

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

fn consume_unpin(&mut self, amt: usize) where
    Self: Unpin, [src]

A convenience for calling AsyncBufRead::consume on Unpin IO types. Read more

fn read_until(
    &'a mut self,
    byte: u8,
    buf: &'a mut Vec<u8, Global>
) -> ReadUntil<'a, Self>ⓘ

Notable traits for ReadUntil<'_, R>

impl<'_, R> Future for ReadUntil<'_, R> where
    R: AsyncBufRead + Unpin + ?Sized,  type Output = Result<usize, Error>;
 where
    Self: Unpin, [src]

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

fn read_line(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self>ⓘ

Notable traits for ReadLine<'_, R>

impl<'_, R> Future for ReadLine<'_, R> where
    R: AsyncBufRead + Unpin + ?Sized,  type Output = Result<usize, Error>;
 where
    Self: Unpin, [src]

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

fn lines(self) -> Lines<Self>[src]

Returns a stream over the lines of this reader. This method is the async equivalent to BufRead::lines. Read more

impl<R> AsyncReadExt for R where
    R: AsyncRead + ?Sized, [src]

fn chain<R>(self, next: R) -> Chain<Self, R> where
    R: AsyncRead, [src]

Creates an adaptor which will chain this stream with another. Read more

fn read(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self>ⓘ

Notable traits for Read<'_, R>

impl<'_, R> Future for Read<'_, R> where
    R: AsyncRead + Unpin + ?Sized,  type Output = Result<usize, Error>;
 where
    Self: Unpin, [src]

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, [src]

Creates a future which will read from the AsyncRead into bufs using vectored IO operations. Read more

fn read_exact(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self>ⓘ

Notable traits for ReadExact<'_, R>

impl<'_, R> Future for ReadExact<'_, R> where
    R: AsyncRead + Unpin + ?Sized,  type Output = Result<(), Error>;
 where
    Self: Unpin, [src]

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

fn read_to_end(
    &'a mut self,
    buf: &'a mut Vec<u8, Global>
) -> ReadToEnd<'a, Self>ⓘ

Notable traits for ReadToEnd<'_, A>

impl<'_, A> Future for ReadToEnd<'_, A> where
    A: AsyncRead + Unpin + ?Sized,  type Output = Result<usize, Error>;
 where
    Self: Unpin, [src]

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, [src]

Creates a future which will read all the bytes from this AsyncRead. Read more

fn split(self) -> (ReadHalf<Self>, WriteHalf<Self>) where
    Self: AsyncWrite, [src]

Helper method for splitting this read/write object into two halves. Read more

fn take(self, limit: u64) -> Take<Self>[src]

Creates an AsyncRead adapter which will read at most limit bytes from the underlying reader. Read more

fn compat(self) -> Compat<Self>ⓘ

Notable traits for Compat<R>

impl<R> Read for Compat<R> where
    R: AsyncRead + Unpin, impl<W> Write for Compat<W> where
    W: AsyncWrite + Unpin, 
 where
    Self: Unpin, [src]

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

impl<S> AsyncSeekExt for S where
    S: AsyncSeek + ?Sized, [src]

fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>ⓘ

Notable traits for Seek<'_, S>

impl<'_, S> Future for Seek<'_, S> where
    S: AsyncSeek + Unpin + ?Sized,  type Output = Result<u64, Error>;
 where
    Self: Unpin, [src]

Creates a future which will seek an IO object, and then yield the new position in the object and the object itself. Read more

fn stream_position(&mut self) -> Seek<'_, Self>ⓘ

Notable traits for Seek<'_, S>

impl<'_, S> Future for Seek<'_, S> where
    S: AsyncSeek + Unpin + ?Sized,  type Output = Result<u64, Error>;
 where
    Self: Unpin, [src]

Creates a future which will return the current seek position from the start of the stream. Read more

impl<W> AsyncWriteExt for W where
    W: AsyncWrite + ?Sized, [src]

fn flush(&mut self) -> Flush<'_, Self>ⓘ

Notable traits for Flush<'_, W>

impl<'_, W> Future for Flush<'_, W> where
    W: AsyncWrite + Unpin + ?Sized,  type Output = Result<(), Error>;
 where
    Self: Unpin, [src]

Creates a future which will entirely flush this AsyncWrite. Read more

fn close(&mut self) -> Close<'_, Self>ⓘ

Notable traits for Close<'_, W>

impl<'_, W> Future for Close<'_, W> where
    W: AsyncWrite + Unpin + ?Sized,  type Output = Result<(), Error>;
 where
    Self: Unpin, [src]

Creates a future which will entirely close this AsyncWrite.

fn write(&'a mut self, buf: &'a [u8]) -> Write<'a, Self>ⓘ

Notable traits for Write<'_, W>

impl<'_, W> Future for Write<'_, W> where
    W: AsyncWrite + Unpin + ?Sized,  type Output = Result<usize, Error>;
 where
    Self: Unpin, [src]

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, [src]

Creates a future which will write bytes from bufs into the object using vectored IO operations. Read more

fn write_all(&'a mut self, buf: &'a [u8]) -> WriteAll<'a, Self>ⓘ

Notable traits for WriteAll<'_, W>

impl<'_, W> Future for WriteAll<'_, W> where
    W: AsyncWrite + Unpin + ?Sized,  type Output = Result<(), Error>;
 where
    Self: Unpin, [src]

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, [src]

Attempts to write multiple buffers into this writer. Read more

fn compat_write(self) -> Compat<Self>ⓘ

Notable traits for Compat<R>

impl<R> Read for Compat<R> where
    R: AsyncRead + Unpin, impl<W> Write for Compat<W> where
    W: AsyncWrite + Unpin, 
 where
    Self: Unpin, [src]

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

fn into_sink<Item>(self) -> IntoSink<Self, Item> where
    Item: AsRef<[u8]>, [src]

Allow using an AsyncWrite as a Sink<Item: AsRef<[u8]>>. Read more

impl<T> Borrow<T> for T where
    T: ?Sized, [src]

pub fn borrow(&self) -> &T[src]

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T where
    T: ?Sized, [src]

pub fn borrow_mut(&mut self) -> &mut T[src]

Mutably borrows from an owned value. Read more

impl<T> From<T> for T[src]

pub fn from(t: T) -> T[src]

Performs the conversion.

impl<T, U> Into<U> for T where
    U: From<T>, [src]

pub fn into(self) -> U[src]

Performs the conversion.

impl<T> ToOwned for T where
    T: Clone, [src]

type Owned = T

The resulting type after obtaining ownership.

pub fn to_owned(&self) -> T[src]

Creates owned data from borrowed data, usually by cloning. Read more

pub fn clone_into(&self, target: &mut T)[src]

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

impl<T, U> TryFrom<U> for T where
    U: Into<T>, [src]

type Error = Infallible

The type returned in the event of a conversion error.

pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>[src]

Performs the conversion.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, [src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>[src]

Performs the conversion.