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|
#![allow(dead_code)] // TODO
use std::{
io, mem,
pin::Pin,
task::{Context, Poll},
};
use async_compression::tokio::bufread::{BzDecoder, GzipDecoder, XzDecoder};
use futures::ready;
use pin_project::pin_project;
use tokio::io::{AsyncBufRead, AsyncRead, BufReader, ReadBuf};
const GZIP_MAGIC: [u8; 2] = [0x1f, 0x8b];
const BZIP2_MAGIC: [u8; 3] = *b"BZh";
const XZ_MAGIC: [u8; 6] = [0xfd, 0x37, 0x7a, 0x58, 0x5a, 0x00];
const BYTES_NEEDED: usize = 6;
#[derive(Debug, Clone, Copy)]
enum Algorithm {
Gzip,
Bzip2,
Xz,
}
impl Algorithm {
fn from_magic(magic: &[u8]) -> Option<Self> {
if magic.starts_with(&GZIP_MAGIC) {
Some(Self::Gzip)
} else if magic.starts_with(&BZIP2_MAGIC) {
Some(Self::Bzip2)
} else if magic.starts_with(&XZ_MAGIC) {
Some(Self::Xz)
} else {
None
}
}
}
#[pin_project]
struct WithPreexistingBuffer<R> {
buffer: Vec<u8>,
#[pin]
inner: R,
}
impl<R> AsyncRead for WithPreexistingBuffer<R>
where
R: AsyncRead,
{
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
let this = self.project();
if !this.buffer.is_empty() {
// TODO: check if the buffer fits first
buf.put_slice(this.buffer);
this.buffer.clear();
}
this.inner.poll_read(cx, buf)
}
}
#[pin_project(project = DecompressedReaderInnerProj)]
enum DecompressedReaderInner<R> {
Unknown {
buffer: Vec<u8>,
#[pin]
inner: Option<R>,
},
Gzip(#[pin] GzipDecoder<BufReader<WithPreexistingBuffer<R>>>),
Bzip2(#[pin] BzDecoder<BufReader<WithPreexistingBuffer<R>>>),
Xz(#[pin] XzDecoder<BufReader<WithPreexistingBuffer<R>>>),
}
impl<R> DecompressedReaderInner<R>
where
R: AsyncBufRead,
{
fn switch_to(&mut self, algorithm: Algorithm) {
let (buffer, inner) = match self {
DecompressedReaderInner::Unknown { buffer, inner } => {
(mem::take(buffer), inner.take().unwrap())
}
DecompressedReaderInner::Gzip(_)
| DecompressedReaderInner::Bzip2(_)
| DecompressedReaderInner::Xz(_) => unreachable!(),
};
let inner = BufReader::new(WithPreexistingBuffer { buffer, inner });
*self = match algorithm {
Algorithm::Gzip => Self::Gzip(GzipDecoder::new(inner)),
Algorithm::Bzip2 => Self::Bzip2(BzDecoder::new(inner)),
Algorithm::Xz => Self::Xz(XzDecoder::new(inner)),
}
}
}
impl<R> AsyncRead for DecompressedReaderInner<R>
where
R: AsyncBufRead,
{
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
match self.project() {
DecompressedReaderInnerProj::Unknown { .. } => {
unreachable!("Can't call poll_read on Unknown")
}
DecompressedReaderInnerProj::Gzip(inner) => inner.poll_read(cx, buf),
DecompressedReaderInnerProj::Bzip2(inner) => inner.poll_read(cx, buf),
DecompressedReaderInnerProj::Xz(inner) => inner.poll_read(cx, buf),
}
}
}
#[pin_project]
pub struct DecompressedReader<R> {
#[pin]
inner: DecompressedReaderInner<R>,
switch_to: Option<Algorithm>,
}
impl<R> DecompressedReader<R> {
pub fn new(inner: R) -> Self {
Self {
inner: DecompressedReaderInner::Unknown {
buffer: vec![0; BYTES_NEEDED],
inner: Some(inner),
},
switch_to: None,
}
}
}
impl<R> AsyncRead for DecompressedReader<R>
where
R: AsyncBufRead + Unpin,
{
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
let mut this = self.project();
let (buffer, inner) = match this.inner.as_mut().project() {
DecompressedReaderInnerProj::Gzip(inner) => return inner.poll_read(cx, buf),
DecompressedReaderInnerProj::Bzip2(inner) => return inner.poll_read(cx, buf),
DecompressedReaderInnerProj::Xz(inner) => return inner.poll_read(cx, buf),
DecompressedReaderInnerProj::Unknown { buffer, inner } => (buffer, inner),
};
let mut our_buf = ReadBuf::new(buffer);
if let Err(e) = ready!(inner.as_pin_mut().unwrap().poll_read(cx, &mut our_buf)) {
return Poll::Ready(Err(e));
}
let data = our_buf.filled();
if data.len() >= BYTES_NEEDED {
if let Some(algorithm) = Algorithm::from_magic(data) {
this.inner.as_mut().switch_to(algorithm);
} else {
return Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidData,
"tar data not gz, bzip2, or xz compressed",
)));
}
this.inner.poll_read(cx, buf)
} else {
cx.waker().wake_by_ref();
Poll::Pending
}
}
}
#[cfg(test)]
mod tests {
use std::path::Path;
use async_compression::tokio::bufread::GzipEncoder;
use futures::TryStreamExt;
use rstest::rstest;
use tokio::io::{AsyncReadExt, BufReader};
use tokio_tar::Archive;
use super::*;
#[tokio::test]
async fn gzip() {
let data = b"abcdefghijk";
let mut enc = GzipEncoder::new(&data[..]);
let mut gzipped = vec![];
enc.read_to_end(&mut gzipped).await.unwrap();
let mut reader = DecompressedReader::new(BufReader::new(&gzipped[..]));
let mut round_tripped = vec![];
reader.read_to_end(&mut round_tripped).await.unwrap();
assert_eq!(data[..], round_tripped[..]);
}
#[rstest]
#[case::gzip(include_bytes!("tests/blob.tar.gz"))]
#[case::bzip2(include_bytes!("tests/blob.tar.bz2"))]
#[case::xz(include_bytes!("tests/blob.tar.xz"))]
#[tokio::test]
async fn compressed_tar(#[case] data: &[u8]) {
let reader = DecompressedReader::new(BufReader::new(data));
let mut archive = Archive::new(reader);
let mut entries: Vec<_> = archive.entries().unwrap().try_collect().await.unwrap();
assert_eq!(entries.len(), 1);
assert_eq!(entries[0].path().unwrap().as_ref(), Path::new("empty"));
let mut data = String::new();
entries[0].read_to_string(&mut data).await.unwrap();
assert_eq!(data, "");
}
}
|
