Struct smol::io::BlockOn

source · []
pub struct BlockOn<T>(_);
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

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);

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();

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();

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

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

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

🔬 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 more

Read all bytes into buf until the delimiter byte or EOF is reached. Read more

Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided buffer. Read more

Returns an iterator over the contents of this reader split on the byte byte. Read more

Returns an iterator over the lines of this reader. Read more

Formats the value using the given formatter. Read more

Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more

Like read, except that it reads into a slice of buffers. Read more

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

Determines if this Reader has an efficient read_vectored implementation. Read more

Read all bytes until EOF in this source, placing them into buf. Read more

Read all bytes until EOF in this source, appending them to buf. Read more

Read the exact number of bytes required to fill buf. Read more

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

Pull some bytes from this source into the specified buffer. Read more

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

Read the exact number of bytes required to fill buf. Read more

Creates a “by reference” adaptor for this instance of Read. Read more

Transforms this Read instance to an Iterator over its bytes. Read more

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

Creates an adapter which will read at most limit bytes from it. Read more

Seek to an offset, in bytes, in a stream. Read more

Rewind to the beginning of a stream. Read more

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

Returns the length of this stream (in bytes). Read more

Returns the current seek position from the start of the stream. Read more

Write a buffer into this writer, returning how many bytes were written. Read more

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

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

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

Determines if this Writer has an efficient write_vectored implementation. Read more

Attempts to write an entire buffer into this writer. Read more

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

Attempts to write multiple buffers into this writer. Read more

Writes a formatted string into this writer, returning any error encountered. Read more

Creates a “by reference” adapter for this instance of Write. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.