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use crate::{BufResult, IoBufMut, Piece, PieceList};
mod pipe;
pub use pipe::*;
mod non_uring;
#[allow(async_fn_in_trait)] // we never require Send
pub trait ReadOwned {
async fn read_owned<B: IoBufMut>(&mut self, buf: B) -> BufResult<usize, B>;
}
#[allow(async_fn_in_trait)] // we never require Send
pub trait WriteOwned {
/// Write a single buffer, taking ownership for the duration of the write.
/// Might perform a partial write, see [WriteOwned::write_all_owned]
async fn write_owned(&mut self, buf: impl Into<Piece>) -> BufResult<usize, Piece>;
/// Write a single buffer, re-trying the write if the kernel does a partial
/// write.
async fn write_all_owned(&mut self, buf: impl Into<Piece>) -> std::io::Result<()> {
let mut buf = buf.into();
let mut written = 0;
let len = buf.len();
while written < len {
let (res, slice) = self.write_owned(buf).await;
let n = res?;
if n == 0 {
return Err(std::io::Error::new(
std::io::ErrorKind::WriteZero,
"write zero",
));
}
(_, buf) = slice.split_at(n);
written += n;
}
Ok(())
}
/// Write a list of buffers, taking ownership for the duration of the write.
/// Might perform a partial write, see [WriteOwned::writev_all_owned]
async fn writev_owned(&mut self, list: &PieceList) -> std::io::Result<usize> {
let mut total = 0;
for buf in list.pieces.iter().cloned() {
let buf_len = buf.len();
let (res, _) = self.write_owned(buf).await;
match res {
Ok(0) => {
return Err(std::io::Error::new(
std::io::ErrorKind::WriteZero,
"write zero",
));
}
Ok(n) => {
total += n;
if n < buf_len {
// partial write, return the buffer list so the caller
// might choose to try the write again
return Ok(total);
}
}
Err(e) => {
return Err(e);
}
}
}
Ok(total)
}
/// Write a list of buffers, re-trying the write if the kernel does a
/// partial write.
async fn writev_all_owned(&mut self, mut list: PieceList) -> std::io::Result<()> {
while !list.is_empty() {
let n = self.writev_owned(&list).await?;
if n == 0 {
return Err(std::io::Error::new(
std::io::ErrorKind::WriteZero,
"write zero",
));
}
let mut n = n;
while n > 0 {
// pop and/or split items from the list
let next_item = list.pieces.front_mut().unwrap();
let next_item_len = next_item.len();
if n < next_item_len {
// the number of bytes written falls in the middle of the buffer.
// split the buffer and push the remainder back to the list
let next_item = list.pieces.pop_front().unwrap();
let (l, r) = next_item.split_at(n);
n -= l.len();
list.pieces.push_front(r);
} else {
// the whole buffer was written, pop it from the list
list.pieces.pop_front();
n -= next_item_len;
}
}
}
Ok(())
}
/// Shuts down the write end of this socket. This flushes
/// any data that may not have been send.
async fn shutdown(&mut self) -> std::io::Result<()>;
}
#[cfg(all(test, not(feature = "miri")))]
mod tests {
use std::{cell::RefCell, rc::Rc};
use crate::{io::WriteOwned, BufResult, Piece, PieceList};
#[test]
fn test_write_all() {
enum Mode {
WriteZero,
WritePartial,
}
struct Writer {
mode: Mode,
bytes: Rc<RefCell<Vec<u8>>>,
}
impl WriteOwned for Writer {
async fn write_owned(&mut self, buf: impl Into<Piece>) -> BufResult<usize, Piece> {
let buf = buf.into();
assert!(!buf.is_empty(), "zero-length writes are forbidden");
match self.mode {
Mode::WriteZero => (Ok(0), buf),
Mode::WritePartial => {
let n = match buf.len() {
1 => 1,
_ => buf.len() / 2,
};
self.bytes.borrow_mut().extend_from_slice(&buf[..n]);
(Ok(n), buf)
}
}
}
async fn shutdown(&mut self) -> std::io::Result<()> {
Ok(())
}
}
crate::start(async move {
let mut writer = Writer {
mode: Mode::WriteZero,
bytes: Default::default(),
};
let buf_a = vec![1, 2, 3, 4, 5];
let res = writer.write_all_owned(buf_a).await;
assert!(res.is_err());
let mut writer = Writer {
mode: Mode::WriteZero,
bytes: Default::default(),
};
let buf_a = vec![1, 2, 3, 4, 5];
let buf_b = vec![6, 7, 8, 9, 10];
let res = writer
.writev_all_owned(PieceList::single(buf_a).followed_by(buf_b))
.await;
assert!(res.is_err());
let mut writer = Writer {
mode: Mode::WritePartial,
bytes: Default::default(),
};
let buf_a = vec![1, 2, 3, 4, 5];
writer.write_all_owned(buf_a).await.unwrap();
assert_eq!(&writer.bytes.borrow()[..], &[1, 2, 3, 4, 5]);
let mut writer = Writer {
mode: Mode::WritePartial,
bytes: Default::default(),
};
let buf_a = vec![1, 2, 3, 4, 5];
let buf_b = vec![6, 7, 8, 9, 10];
writer
.writev_all_owned(PieceList::single(buf_a).followed_by(buf_b))
.await
.unwrap();
assert_eq!(&writer.bytes.borrow()[..], &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
});
}
}
pub trait IntoHalves: 'static {
type Read: ReadOwned;
type Write: WriteOwned;
/// Split this into an owned read half and an owned write half.
fn into_halves(self) -> (Self::Read, Self::Write);
}