Struct futures_lite::io::BlockOn
source · pub struct BlockOn<T>(/* private fields */);
Expand description
Blocks on all async I/O operations and implements std::io
traits.
Sometimes async I/O needs to be used in a blocking manner. If calling future::block_on()
manually all the time becomes too tedious, use this type for more convenient blocking on async
I/O operations.
This type implements traits Read
, Write
, or
Seek
if the inner type implements AsyncRead
, AsyncWrite
, or
AsyncSeek
, respectively.
If writing data through the Write
trait, make sure to flush before
dropping the BlockOn
handle or some buffered data might get lost.
§Examples
use futures_lite::io::BlockOn;
use futures_lite::pin;
use std::io::Read;
let reader: &[u8] = b"hello";
pin!(reader);
let mut blocking_reader = BlockOn::new(reader);
let mut contents = String::new();
// This line blocks - note that there is no await:
blocking_reader.read_to_string(&mut contents)?;
Implementations§
source§impl<T> BlockOn<T>
impl<T> BlockOn<T>
sourcepub fn new(io: T) -> BlockOn<T> ⓘ
pub fn new(io: T) -> BlockOn<T> ⓘ
Wraps an async I/O handle into a blocking interface.
§Examples
use futures_lite::io::BlockOn;
use futures_lite::pin;
let reader: &[u8] = b"hello";
pin!(reader);
let blocking_reader = BlockOn::new(reader);
sourcepub fn get_ref(&self) -> &T
pub fn get_ref(&self) -> &T
Gets a reference to the async I/O handle.
§Examples
use futures_lite::io::BlockOn;
use futures_lite::pin;
let reader: &[u8] = b"hello";
pin!(reader);
let blocking_reader = BlockOn::new(reader);
let r = blocking_reader.get_ref();
sourcepub fn get_mut(&mut self) -> &mut T
pub fn get_mut(&mut self) -> &mut T
Gets a mutable reference to the async I/O handle.
§Examples
use futures_lite::io::BlockOn;
use futures_lite::pin;
let reader: &[u8] = b"hello";
pin!(reader);
let mut blocking_reader = BlockOn::new(reader);
let r = blocking_reader.get_mut();
sourcepub fn into_inner(self) -> T
pub fn into_inner(self) -> T
Extracts the inner async I/O handle.
§Examples
use futures_lite::io::BlockOn;
use futures_lite::pin;
let reader: &[u8] = b"hello";
pin!(reader);
let blocking_reader = BlockOn::new(reader);
let inner = blocking_reader.into_inner();
Trait Implementations§
source§impl<T: AsyncBufRead + Unpin> BufRead for BlockOn<T>
impl<T: AsyncBufRead + Unpin> BufRead for BlockOn<T>
source§fn fill_buf(&mut self) -> Result<&[u8]>
fn fill_buf(&mut self) -> Result<&[u8]>
Returns the contents of the internal buffer, filling it with more data
from the inner reader if it is empty. Read more
source§fn consume(&mut self, amt: usize)
fn consume(&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 read
. Read moresource§fn has_data_left(&mut self) -> Result<bool, Error>
fn has_data_left(&mut self) -> Result<bool, Error>
🔬This is a nightly-only experimental API. (
buf_read_has_data_left
)Check if the underlying
Read
has any data left to be read. Read moresource§fn skip_until(&mut self, byte: u8) -> Result<usize, Error>
fn skip_until(&mut self, byte: u8) -> Result<usize, Error>
🔬This is a nightly-only experimental API. (
bufread_skip_until
)Skip all bytes until the delimiter
byte
or EOF is reached. Read more1.0.0 · source§fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>
fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>
Read all bytes until a newline (the
0xA
byte) is reached, and append
them to the provided String
buffer. Read moresource§impl<T: AsyncRead + Unpin> Read for BlockOn<T>
impl<T: AsyncRead + Unpin> Read for BlockOn<T>
source§fn read(&mut self, buf: &mut [u8]) -> Result<usize>
fn read(&mut self, buf: &mut [u8]) -> Result<usize>
Pull some bytes from this source into the specified buffer, returning
how many bytes were read. Read more
1.36.0 · source§fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>
Like
read
, except that it reads into a slice of buffers. Read moresource§fn is_read_vectored(&self) -> bool
fn is_read_vectored(&self) -> bool
🔬This is a nightly-only experimental API. (
can_vector
)1.0.0 · source§fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
Read all bytes until EOF in this source, placing them into
buf
. Read more1.0.0 · source§fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
Read all bytes until EOF in this source, appending them to
buf
. Read more1.6.0 · source§fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
Read the exact number of bytes required to fill
buf
. Read moresource§fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>
fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>
🔬This is a nightly-only experimental API. (
read_buf
)Pull some bytes from this source into the specified buffer. Read more
source§fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>
fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>
🔬This is a nightly-only experimental API. (
read_buf
)Read the exact number of bytes required to fill
cursor
. Read more1.0.0 · source§fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,
fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,
Creates a “by reference” adaptor for this instance of
Read
. Read moresource§impl<T: AsyncSeek + Unpin> Seek for BlockOn<T>
impl<T: AsyncSeek + Unpin> Seek for BlockOn<T>
source§fn seek(&mut self, pos: SeekFrom) -> Result<u64>
fn seek(&mut self, pos: SeekFrom) -> Result<u64>
Seek to an offset, in bytes, in a stream. Read more
1.55.0 · source§fn rewind(&mut self) -> Result<(), Error>
fn rewind(&mut self) -> Result<(), Error>
Rewind to the beginning of a stream. Read more
source§fn stream_len(&mut self) -> Result<u64, Error>
fn stream_len(&mut self) -> Result<u64, Error>
🔬This is a nightly-only experimental API. (
seek_stream_len
)Returns the length of this stream (in bytes). Read more
source§impl<T: AsyncWrite + Unpin> Write for BlockOn<T>
impl<T: AsyncWrite + Unpin> Write for BlockOn<T>
source§fn write(&mut self, buf: &[u8]) -> Result<usize>
fn write(&mut self, buf: &[u8]) -> Result<usize>
Write a buffer into this writer, returning how many bytes were written. Read more
source§fn flush(&mut self) -> Result<()>
fn flush(&mut self) -> Result<()>
Flush this output stream, ensuring that all intermediately buffered
contents reach their destination. Read more
source§fn is_write_vectored(&self) -> bool
fn is_write_vectored(&self) -> bool
🔬This is a nightly-only experimental API. (
can_vector
)1.0.0 · source§fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
Attempts to write an entire buffer into this writer. Read more
source§fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>
fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>
🔬This is a nightly-only experimental API. (
write_all_vectored
)Attempts to write multiple buffers into this writer. Read more
Auto Trait Implementations§
impl<T> Freeze for BlockOn<T>where
T: Freeze,
impl<T> RefUnwindSafe for BlockOn<T>where
T: RefUnwindSafe,
impl<T> Send for BlockOn<T>where
T: Send,
impl<T> Sync for BlockOn<T>where
T: Sync,
impl<T> Unpin for BlockOn<T>where
T: Unpin,
impl<T> UnwindSafe for BlockOn<T>where
T: UnwindSafe,
Blanket Implementations§
source§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
Mutably borrows from an owned value. Read more