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Refactor: Simplify AsyncBufWrite #423

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Merged
NobodyXu merged 1 commit into from
Nov 18, 2025
Merged

Refactor: Simplify AsyncBufWrite #423

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15 changes: 2 additions & 13 deletions crates/async-compression/src/generic/write/buf_write.rs
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
use super::Buffer;
use std::{
io,
pin::Pin,
Expand All @@ -16,17 +17,5 @@ pub(crate) trait AsyncBufWrite {
fn poll_partial_flush_buf(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<io::Result<&mut [u8]>>;

/// Tells this buffer that `amt` bytes have been written to its buffer, so they should be
/// written out to the underlying IO when possible.
///
/// This function is a lower-level call. It needs to be paired with the `poll_flush_buf` method to
/// function properly. This function does not perform any I/O, it simply informs this object
/// that some amount of its buffer, returned from `poll_flush_buf`, has been written to and should
/// be sent. As such, this function may do odd things if `poll_flush_buf` isn't
/// called before calling it.
///
/// The `amt` must be `<=` the number of bytes in the buffer returned by `poll_flush_buf`.
fn produce(self: Pin<&mut Self>, amt: usize);
) -> Poll<io::Result<Buffer<'_>>>;
}
31 changes: 17 additions & 14 deletions crates/async-compression/src/generic/write/buf_writer.rs
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Expand Up @@ -3,6 +3,7 @@
// with those methods.

use super::AsyncBufWrite;
use compression_core::util::WriteBuffer;
use futures_core::ready;
use std::{
fmt, io,
Expand Down Expand Up @@ -133,7 +134,7 @@ impl BufWriter {
pub fn poll_partial_flush_buf(
&mut self,
poll_write: &mut dyn FnMut(&[u8]) -> Poll<io::Result<usize>>,
) -> Poll<io::Result<&mut [u8]>> {
) -> Poll<io::Result<Buffer<'_>>> {
ready!(self.partial_flush_buf(poll_write))?;

// when the flushed data is larger than or equal to half of yet-to-be-flushed data,
Expand All @@ -146,21 +147,27 @@ impl BufWriter {
self.remove_written();
}

Poll::Ready(Ok(&mut self.buf[self.buffered..]))
Poll::Ready(Ok(Buffer {
write_buffer: WriteBuffer::new_initialized(&mut self.buf[self.buffered..]),
buffered: &mut self.buffered,
}))
}
}

pub struct Buffer<'a> {
buffered: &'a mut usize,
pub write_buffer: WriteBuffer<'a>,
}

pub fn produce(&mut self, amt: usize) {
debug_assert!(
self.buffered + amt <= self.buf.len(),
"produce called with amt exceeding buffer capacity"
);
self.buffered += amt;
impl Drop for Buffer<'_> {
fn drop(&mut self) {
*self.buffered += self.write_buffer.written_len();
}
}

macro_rules! impl_buf_writer {
($poll_close: tt) => {
use crate::generic::write::{AsyncBufWrite, BufWriter as GenericBufWriter};
use crate::generic::write::{AsyncBufWrite, BufWriter as GenericBufWriter, Buffer};
use futures_core::ready;
use pin_project_lite::pin_project;

Expand Down Expand Up @@ -258,15 +265,11 @@ macro_rules! impl_buf_writer {
fn poll_partial_flush_buf(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<io::Result<&mut [u8]>> {
) -> Poll<io::Result<Buffer<'_>>> {
let this = self.project();
this.inner
.poll_partial_flush_buf(&mut get_poll_write(this.writer, cx))
}

fn produce(self: Pin<&mut Self>, amt: usize) {
self.project().inner.produce(amt)
}
}
};
}
Expand Down
22 changes: 8 additions & 14 deletions crates/async-compression/src/generic/write/decoder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,20 +39,20 @@ impl Decoder {
decoder: &mut dyn DecodeV2,
) -> Poll<io::Result<()>> {
loop {
let output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let mut output = WriteBuffer::new_initialized(output);
let mut output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let output = &mut output.write_buffer;

self.state = match self.state {
State::Decoding => {
if decoder.decode(input, &mut output)? {
if decoder.decode(input, output)? {
State::Finishing
} else {
State::Decoding
}
}

State::Finishing => {
if decoder.finish(&mut output)? {
if decoder.finish(output)? {
State::Done
} else {
State::Finishing
Expand All @@ -64,9 +64,6 @@ impl Decoder {
}
};

let produced = output.written_len();
writer.as_mut().produce(produced);

if let State::Done = self.state {
return Poll::Ready(Ok(()));
}
Expand Down Expand Up @@ -103,17 +100,17 @@ impl Decoder {
decoder: &mut dyn DecodeV2,
) -> Poll<io::Result<()>> {
loop {
let output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let mut output = WriteBuffer::new_initialized(output);
let mut output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let output = &mut output.write_buffer;

let (state, done) = match self.state {
State::Decoding => {
let done = decoder.flush(&mut output)?;
let done = decoder.flush(output)?;
(State::Decoding, done)
}

State::Finishing => {
if decoder.finish(&mut output)? {
if decoder.finish(output)? {
(State::Done, false)
} else {
(State::Finishing, false)
Expand All @@ -125,9 +122,6 @@ impl Decoder {

self.state = state;

let produced = output.written_len();
writer.as_mut().produce(produced);

if done {
break Poll::Ready(Ok(()));
}
Expand Down
27 changes: 9 additions & 18 deletions crates/async-compression/src/generic/write/encoder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,12 +39,12 @@ impl Encoder {
encoder: &mut dyn EncodeV2,
) -> Poll<io::Result<()>> {
loop {
let output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let mut output = WriteBuffer::new_initialized(output);
let mut output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let output = &mut output.write_buffer;

self.state = match self.state {
State::Encoding => {
encoder.encode(input, &mut output)?;
encoder.encode(input, output)?;
State::Encoding
}

Expand All @@ -53,9 +53,6 @@ impl Encoder {
}
};

let produced = output.written_len();
writer.as_mut().produce(produced);

if input.unwritten().is_empty() {
break Poll::Ready(Ok(()));
}
Expand Down Expand Up @@ -88,20 +85,17 @@ impl Encoder {
encoder: &mut dyn EncodeV2,
) -> Poll<io::Result<()>> {
loop {
let output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let mut output = WriteBuffer::new_initialized(output);
let mut output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let output = &mut output.write_buffer;

let done = match self.state {
State::Encoding => encoder.flush(&mut output)?,
State::Encoding => encoder.flush(output)?,

State::Finishing | State::Done => {
break Poll::Ready(Err(io::Error::other("Flush after close")))
}
};

let produced = output.written_len();
writer.as_mut().produce(produced);

if done {
break Poll::Ready(Ok(()));
}
Expand All @@ -115,12 +109,12 @@ impl Encoder {
encoder: &mut dyn EncodeV2,
) -> Poll<io::Result<()>> {
loop {
let output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let mut output = WriteBuffer::new_initialized(output);
let mut output = ready!(writer.as_mut().poll_partial_flush_buf(cx))?;
let output = &mut output.write_buffer;

self.state = match self.state {
State::Encoding | State::Finishing => {
if encoder.finish(&mut output)? {
if encoder.finish(output)? {
State::Done
} else {
State::Finishing
Expand All @@ -130,9 +124,6 @@ impl Encoder {
State::Done => State::Done,
};

let produced = output.written_len();
writer.as_mut().produce(produced);

if let State::Done = self.state {
break Poll::Ready(Ok(()));
}
Expand Down