Struct partial_io::PartialAsyncRead

source · [−]

pub struct PartialAsyncRead<R> { /* private fields */ }

Expand description

A wrapper that breaks inner AsyncRead instances up according to the provided iterator.

Available with the futures03 feature for futures traits, and with the tokio1 feature for tokio traits.

Examples

This example uses tokio.

use partial_io::{PartialAsyncRead, PartialOp};
use std::io::{self, Cursor};
use tokio::io::AsyncReadExt;

#[tokio::main]
async fn main() -> io::Result<()> {
    let reader = Cursor::new(vec![1, 2, 3, 4]);
    // Sequential calls to `poll_read()` and the other `poll_` methods simulate the following behavior:
    let iter = vec![
        PartialOp::Err(io::ErrorKind::WouldBlock),   // A not-ready state.
        PartialOp::Limited(2),                       // Only allow 2 bytes to be read.
        PartialOp::Err(io::ErrorKind::InvalidData),  // Error from the underlying stream.
        PartialOp::Unlimited,                        // Allow as many bytes to be read as possible.
    ];
    let mut partial_reader = PartialAsyncRead::new(reader, iter);
    let mut out = vec![0; 256];

    // This causes poll_read to be called twice, yielding after the first call (WouldBlock).
    assert_eq!(partial_reader.read(&mut out).await?, 2, "first read with Limited(2)");
    assert_eq!(&out[..4], &[1, 2, 0, 0]);

    // This next call returns an error.
    assert_eq!(
        partial_reader.read(&mut out[2..]).await.unwrap_err().kind(),
        io::ErrorKind::InvalidData,
    );

    // And this one causes the last two bytes to be written.
    assert_eq!(partial_reader.read(&mut out[2..]).await?, 2, "second read with Unlimited");
    assert_eq!(&out[..4], &[1, 2, 3, 4]);

    Ok(())
}

Implementations

impl<R> PartialAsyncRead<R>

pub fn new<I>(inner: R, iter: I) -> Self where
I: IntoIterator<Item = PartialOp> + 'static,
I::IntoIter: Send,

Available on crate feature futures03 only.

Creates a new PartialAsyncRead wrapper over the reader with the specified PartialOps.

pub fn set_ops<I>(&mut self, iter: I) -> &mut Self where
I: IntoIterator<Item = PartialOp> + 'static,
I::IntoIter: Send,

Available on crate feature futures03 only.

Sets the PartialOps for this reader.

pub fn pin_set_ops<I>(self: Pin<&mut Self>, iter: I) -> Pin<&mut Self> where
I: IntoIterator<Item = PartialOp> + 'static,
I::IntoIter: Send,

Available on crate feature futures03 only.

Sets the PartialOps for this reader in a pinned context.

pub fn get_ref(&self) -> &R

Available on crate feature futures03 only.

Returns a shared reference to the underlying reader.

pub fn get_mut(&mut self) -> &mut R

Available on crate feature futures03 only.

Returns a mutable reference to the underlying reader.

pub fn pin_get_mut(self: Pin<&mut Self>) -> Pin<&mut R>

Available on crate feature futures03 only.

Returns a pinned mutable reference to the underlying reader.

pub fn into_inner(self) -> R

Available on crate feature futures03 only.

Consumes this wrapper, returning the underlying reader.

Trait Implementations

impl<R> AsyncBufRead for PartialAsyncRead<R> where
R: AsyncBufRead,

fn poll_fill_buf(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<&[u8]>>

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

fn consume(self: Pin<&mut Self>, amt: usize)

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<R> AsyncBufRead for PartialAsyncRead<R> where
R: AsyncBufRead,

fn poll_fill_buf(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<&[u8]>>

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

fn consume(self: Pin<&mut Self>, amt: usize)

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<R> AsyncRead for PartialAsyncRead<R> where
R: AsyncRead,

fn poll_read(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    buf: &mut [u8]
) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into buf. Read more

fn poll_read_vectored(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize, Error>>

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

impl<R> AsyncRead for PartialAsyncRead<R> where
R: AsyncRead,

fn poll_read(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    buf: &mut ReadBuf<'_>
) -> Poll<Result<()>>

Attempts to read from the AsyncRead into buf. Read more

impl<R> AsyncSeek for PartialAsyncRead<R> where
R: AsyncSeek,

This is a forwarding impl to support duplex structs.

fn poll_seek(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    pos: SeekFrom
) -> Poll<Result<u64>>

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

impl<R> AsyncSeek for PartialAsyncRead<R> where
R: AsyncSeek,

This is a forwarding impl to support duplex structs.

fn start_seek(self: Pin<&mut Self>, position: SeekFrom) -> Result<()>

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

fn poll_complete(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<u64>>

Waits for a seek operation to complete. Read more

impl<R> AsyncWrite for PartialAsyncRead<R> where
R: AsyncWrite,

This is a forwarding impl to support duplex structs.

fn poll_write(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    buf: &[u8]
) -> Poll<Result<usize>>

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

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

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

fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Attempt to close the object. Read more

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

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

impl<R> AsyncWrite for PartialAsyncRead<R> where
R: AsyncWrite,

This is a forwarding impl to support duplex structs.

fn poll_write(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    buf: &[u8]
) -> Poll<Result<usize>>

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

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

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

fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down. Read more

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

Like poll_write, except that it writes from a slice of buffers. Read more

fn is_write_vectored(&self) -> bool

Determines if this writer has an efficient poll_write_vectored implementation. Read more

impl<R> Debug for PartialAsyncRead<R> where
R: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

impl<'pin, R> Unpin for PartialAsyncRead<R> where
__PartialAsyncRead<'pin, R>: Unpin,

Auto Trait Implementations

impl<R> !RefUnwindSafe for PartialAsyncRead<R>

impl<R> Send for PartialAsyncRead<R> where
R: Send,

impl<R> !Sync for PartialAsyncRead<R>

impl<R> !UnwindSafe for PartialAsyncRead<R>

Blanket Implementations

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

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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

fn fill_buf(&mut self) -> FillBuf<'_, Self> where
Self: Unpin,

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,

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> where
    Self: Unpin,

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> where
Self: Unpin,

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>

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,

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

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

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

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> where
    Self: Unpin,

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> where
Self: Unpin,

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> where
Self: Unpin,

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> where
Self: Unpin,

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

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

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

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

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

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

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

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> where
Self: Unpin,

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,

fn flush(&mut self) -> Flush<'_, Self> where
Self: Unpin,

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

fn close(&mut self) -> Close<'_, Self> where
Self: Unpin,

Creates a future which will entirely close this AsyncWrite.

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

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> where
    Self: Unpin,

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> where
Self: Unpin,

Write data into this object. Read more

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

Available on crate feature sink only.

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

impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

impl<T, U> TryFrom<U> for T where
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

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

Performs the conversion.

impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

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

The type returned in the event of a conversion error.

const: unstable · source

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

Performs the conversion.

impl<V, T> VZip<V> for T where
V: MultiLane<T>,

fn vzip(self) -> V