An executor for isolating blocking I/O in async programs.
Sometimes there's no way to avoid blocking I/O. Consider files or stdin, which have weak async support on modern operating systems. While [IOCP], [AIO], and [io_uring] are possible solutions, they're not always available or ideal.
Since blocking is not allowed inside futures, we must move blocking I/O onto a special thread pool provided by this crate. The pool dynamically spawns and stops threads depending on the current number of running I/O jobs.
Note that there is a limit on the number of active threads. Once that limit is hit, a running job has to finish before others get a chance to run. When a thread is idle, it waits for the next job or shuts down after a certain timeout.
Await a blocking I/O operation with Blocking::new():
```rust use blocking::Blocking; use std::fs;
let contents = Blocking::new(|| fs::readtostring("file.txt")).await?; ```
Or do the same with the blocking! macro:
```rust use blocking::blocking; use std::fs;
let contents = blocking!(fs::readtostring("file.txt"))?; ```
Read a file and pipe its contents to stdout:
```rust use blocking::Blocking; use std::fs::File; use std::io::stdout;
let input = Blocking::new(File::open("file.txt")?); let mut output = Blocking::new(stdout());
futures::io::copy(input, &mut output).await?; ```
Iterate over the contents of a directory:
```rust use blocking::Blocking; use futures::prelude::*; use std::fs;
let mut dir = Blocking::new(fs::read_dir(".")?);
while let Some(item) = dir.next().await { println!("{}", item?.filename().tostring_lossy()); } ```
Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.