io-pipe 0.7.3

A fast and thread-safe library for creating multi-writer and single-reader pipelines in Rust.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

use parking_lot::Mutex;
use std::collections::VecDeque;
use std::fmt::Arguments;
use std::io::{IoSlice, Write};
use std::sync::Arc;

#[derive(Clone, Debug, Default)]
pub(crate) struct State {
    buf: VecDeque<u8>,
}

#[derive(Clone, Debug, Default)]
pub(crate) struct SharedState(Arc<Mutex<State>>);

impl SharedState {
    pub(crate) fn copy_to<T: Write>(&self, writer: &mut T) -> std::io::Result<u64> {
        let self_buf = &mut self.0.lock().buf;
        std::io::copy(self_buf, writer)
    }
}

impl Write for SharedState {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        self.0.lock().buf.write(buf)
    }

    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> std::io::Result<usize> {
        let mut guard = self.0.lock();
        let n = bufs.iter().map(|b| b.len()).sum::<usize>();
        guard.buf.reserve(n);
        guard.buf.extend(bufs.iter().flat_map(|b| b.as_ref()));
        Ok(n)
    }

    fn flush(&mut self) -> std::io::Result<()> {
        self.0.lock().buf.flush()
    }

    fn write_all(&mut self, buf: &[u8]) -> std::io::Result<()> {
        self.0.lock().buf.write_all(buf)
    }

    fn write_fmt(&mut self, fmt: Arguments<'_>) -> std::io::Result<()> {
        self.0.lock().buf.write_fmt(fmt)
    }
}