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use std::error::Error as StdError;
use std::fmt;
use std::io;
use std::usize;
use bytes::Bytes;
use tracing::{debug, trace};
use crate::common::{task, Poll};
use super::io::MemRead;
use super::DecodedLength;
use self::Kind::{Chunked, Eof, Length};
/// Decoders to handle different Transfer-Encodings.
///
/// If a message body does not include a Transfer-Encoding, it *should*
/// include a Content-Length header.
#[derive(Clone, PartialEq)]
pub(crate) struct Decoder {
kind: Kind,
}
#[derive(Debug, Clone, Copy, PartialEq)]
enum Kind {
/// A Reader used when a Content-Length header is passed with a positive integer.
Length(u64),
/// A Reader used when Transfer-Encoding is `chunked`.
Chunked(ChunkedState, u64),
/// A Reader used for responses that don't indicate a length or chunked.
///
/// The bool tracks when EOF is seen on the transport.
///
/// Note: This should only used for `Response`s. It is illegal for a
/// `Request` to be made with both `Content-Length` and
/// `Transfer-Encoding: chunked` missing, as explained from the spec:
///
/// > If a Transfer-Encoding header field is present in a response and
/// > the chunked transfer coding is not the final encoding, the
/// > message body length is determined by reading the connection until
/// > it is closed by the server. If a Transfer-Encoding header field
/// > is present in a request and the chunked transfer coding is not
/// > the final encoding, the message body length cannot be determined
/// > reliably; the server MUST respond with the 400 (Bad Request)
/// > status code and then close the connection.
Eof(bool),
}
#[derive(Debug, PartialEq, Clone, Copy)]
enum ChunkedState {
Size,
SizeLws,
Extension,
SizeLf,
Body,
BodyCr,
BodyLf,
Trailer,
TrailerLf,
EndCr,
EndLf,
End,
}
impl Decoder {
// constructors
pub(crate) fn length(x: u64) -> Decoder {
Decoder {
kind: Kind::Length(x),
}
}
pub(crate) fn chunked() -> Decoder {
Decoder {
kind: Kind::Chunked(ChunkedState::Size, 0),
}
}
pub(crate) fn eof() -> Decoder {
Decoder {
kind: Kind::Eof(false),
}
}
pub(super) fn new(len: DecodedLength) -> Self {
match len {
DecodedLength::CHUNKED => Decoder::chunked(),
DecodedLength::CLOSE_DELIMITED => Decoder::eof(),
length => Decoder::length(length.danger_len()),
}
}
// methods
pub(crate) fn is_eof(&self) -> bool {
matches!(self.kind, Length(0) | Chunked(ChunkedState::End, _) | Eof(true))
}
pub(crate) fn decode<R: MemRead>(
&mut self,
cx: &mut task::Context<'_>,
body: &mut R,
) -> Poll<Result<Bytes, io::Error>> {
trace!("decode; state={:?}", self.kind);
match self.kind {
Length(ref mut remaining) => {
if *remaining == 0 {
Poll::Ready(Ok(Bytes::new()))
} else {
let to_read = *remaining as usize;
let buf = ready!(body.read_mem(cx, to_read))?;
let num = buf.as_ref().len() as u64;
if num > *remaining {
*remaining = 0;
} else if num == 0 {
return Poll::Ready(Err(io::Error::new(
io::ErrorKind::UnexpectedEof,
IncompleteBody,
)));
} else {
*remaining -= num;
}
Poll::Ready(Ok(buf))
}
}
Chunked(ref mut state, ref mut size) => {
loop {
let mut buf = None;
// advances the chunked state
*state = ready!(state.step(cx, body, size, &mut buf))?;
if *state == ChunkedState::End {
trace!("end of chunked");
return Poll::Ready(Ok(Bytes::new()));
}
if let Some(buf) = buf {
return Poll::Ready(Ok(buf));
}
}
}
Eof(ref mut is_eof) => {
if *is_eof {
Poll::Ready(Ok(Bytes::new()))
} else {
// 8192 chosen because its about 2 packets, there probably
// won't be that much available, so don't have MemReaders
// allocate buffers to big
body.read_mem(cx, 8192).map_ok(|slice| {
*is_eof = slice.is_empty();
slice
})
}
}
}
}
#[cfg(test)]
async fn decode_fut<R: MemRead>(&mut self, body: &mut R) -> Result<Bytes, io::Error> {
futures_util::future::poll_fn(move |cx| self.decode(cx, body)).await
}
}
impl fmt::Debug for Decoder {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.kind, f)
}
}
macro_rules! byte (
($rdr:ident, $cx:expr) => ({
let buf = ready!($rdr.read_mem($cx, 1))?;
if !buf.is_empty() {
buf[0]
} else {
return Poll::Ready(Err(io::Error::new(io::ErrorKind::UnexpectedEof,
"unexpected EOF during chunk size line")));
}
})
);
impl ChunkedState {
fn step<R: MemRead>(
&self,
cx: &mut task::Context<'_>,
body: &mut R,
size: &mut u64,
buf: &mut Option<Bytes>,
) -> Poll<Result<ChunkedState, io::Error>> {
use self::ChunkedState::*;
match *self {
Size => ChunkedState::read_size(cx, body, size),
SizeLws => ChunkedState::read_size_lws(cx, body),
Extension => ChunkedState::read_extension(cx, body),
SizeLf => ChunkedState::read_size_lf(cx, body, *size),
Body => ChunkedState::read_body(cx, body, size, buf),
BodyCr => ChunkedState::read_body_cr(cx, body),
BodyLf => ChunkedState::read_body_lf(cx, body),
Trailer => ChunkedState::read_trailer(cx, body),
TrailerLf => ChunkedState::read_trailer_lf(cx, body),
EndCr => ChunkedState::read_end_cr(cx, body),
EndLf => ChunkedState::read_end_lf(cx, body),
End => Poll::Ready(Ok(ChunkedState::End)),
}
}
fn read_size<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
size: &mut u64,
) -> Poll<Result<ChunkedState, io::Error>> {
trace!("Read chunk hex size");
macro_rules! or_overflow {
($e:expr) => (
match $e {
Some(val) => val,
None => return Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidData,
"invalid chunk size: overflow",
))),
}
)
}
let radix = 16;
match byte!(rdr, cx) {
b @ b'0'..=b'9' => {
*size = or_overflow!(size.checked_mul(radix));
*size = or_overflow!(size.checked_add((b - b'0') as u64));
}
b @ b'a'..=b'f' => {
*size = or_overflow!(size.checked_mul(radix));
*size = or_overflow!(size.checked_add((b + 10 - b'a') as u64));
}
b @ b'A'..=b'F' => {
*size = or_overflow!(size.checked_mul(radix));
*size = or_overflow!(size.checked_add((b + 10 - b'A') as u64));
}
b'\t' | b' ' => return Poll::Ready(Ok(ChunkedState::SizeLws)),
b';' => return Poll::Ready(Ok(ChunkedState::Extension)),
b'\r' => return Poll::Ready(Ok(ChunkedState::SizeLf)),
_ => {
return Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid chunk size line: Invalid Size",
)));
}
}
Poll::Ready(Ok(ChunkedState::Size))
}
fn read_size_lws<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
trace!("read_size_lws");
match byte!(rdr, cx) {
// LWS can follow the chunk size, but no more digits can come
b'\t' | b' ' => Poll::Ready(Ok(ChunkedState::SizeLws)),
b';' => Poll::Ready(Ok(ChunkedState::Extension)),
b'\r' => Poll::Ready(Ok(ChunkedState::SizeLf)),
_ => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid chunk size linear white space",
))),
}
}
fn read_extension<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
trace!("read_extension");
// We don't care about extensions really at all. Just ignore them.
// They "end" at the next CRLF.
//
// However, some implementations may not check for the CR, so to save
// them from themselves, we reject extensions containing plain LF as
// well.
match byte!(rdr, cx) {
b'\r' => Poll::Ready(Ok(ChunkedState::SizeLf)),
b'\n' => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidData,
"invalid chunk extension contains newline",
))),
_ => Poll::Ready(Ok(ChunkedState::Extension)), // no supported extensions
}
}
fn read_size_lf<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
size: u64,
) -> Poll<Result<ChunkedState, io::Error>> {
trace!("Chunk size is {:?}", size);
match byte!(rdr, cx) {
b'\n' => {
if size == 0 {
Poll::Ready(Ok(ChunkedState::EndCr))
} else {
debug!("incoming chunked header: {0:#X} ({0} bytes)", size);
Poll::Ready(Ok(ChunkedState::Body))
}
}
_ => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid chunk size LF",
))),
}
}
fn read_body<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
rem: &mut u64,
buf: &mut Option<Bytes>,
) -> Poll<Result<ChunkedState, io::Error>> {
trace!("Chunked read, remaining={:?}", rem);
// cap remaining bytes at the max capacity of usize
let rem_cap = match *rem {
r if r > usize::MAX as u64 => usize::MAX,
r => r as usize,
};
let to_read = rem_cap;
let slice = ready!(rdr.read_mem(cx, to_read))?;
let count = slice.len();
if count == 0 {
*rem = 0;
return Poll::Ready(Err(io::Error::new(
io::ErrorKind::UnexpectedEof,
IncompleteBody,
)));
}
*buf = Some(slice);
*rem -= count as u64;
if *rem > 0 {
Poll::Ready(Ok(ChunkedState::Body))
} else {
Poll::Ready(Ok(ChunkedState::BodyCr))
}
}
fn read_body_cr<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
match byte!(rdr, cx) {
b'\r' => Poll::Ready(Ok(ChunkedState::BodyLf)),
_ => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid chunk body CR",
))),
}
}
fn read_body_lf<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
match byte!(rdr, cx) {
b'\n' => Poll::Ready(Ok(ChunkedState::Size)),
_ => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid chunk body LF",
))),
}
}
fn read_trailer<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
trace!("read_trailer");
match byte!(rdr, cx) {
b'\r' => Poll::Ready(Ok(ChunkedState::TrailerLf)),
_ => Poll::Ready(Ok(ChunkedState::Trailer)),
}
}
fn read_trailer_lf<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
match byte!(rdr, cx) {
b'\n' => Poll::Ready(Ok(ChunkedState::EndCr)),
_ => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid trailer end LF",
))),
}
}
fn read_end_cr<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
match byte!(rdr, cx) {
b'\r' => Poll::Ready(Ok(ChunkedState::EndLf)),
_ => Poll::Ready(Ok(ChunkedState::Trailer)),
}
}
fn read_end_lf<R: MemRead>(
cx: &mut task::Context<'_>,
rdr: &mut R,
) -> Poll<Result<ChunkedState, io::Error>> {
match byte!(rdr, cx) {
b'\n' => Poll::Ready(Ok(ChunkedState::End)),
_ => Poll::Ready(Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Invalid chunk end LF",
))),
}
}
}
#[derive(Debug)]
struct IncompleteBody;
impl fmt::Display for IncompleteBody {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "end of file before message length reached")
}
}
impl StdError for IncompleteBody {}
#[cfg(test)]
mod tests {
use super::*;
use std::pin::Pin;
use std::time::Duration;
use tokio::io::{AsyncRead, ReadBuf};
impl<'a> MemRead for &'a [u8] {
fn read_mem(&mut self, _: &mut task::Context<'_>, len: usize) -> Poll<io::Result<Bytes>> {
let n = std::cmp::min(len, self.len());
if n > 0 {
let (a, b) = self.split_at(n);
let buf = Bytes::copy_from_slice(a);
*self = b;
Poll::Ready(Ok(buf))
} else {
Poll::Ready(Ok(Bytes::new()))
}
}
}
impl<'a> MemRead for &'a mut (dyn AsyncRead + Unpin) {
fn read_mem(&mut self, cx: &mut task::Context<'_>, len: usize) -> Poll<io::Result<Bytes>> {
let mut v = vec![0; len];
let mut buf = ReadBuf::new(&mut v);
ready!(Pin::new(self).poll_read(cx, &mut buf)?);
Poll::Ready(Ok(Bytes::copy_from_slice(&buf.filled())))
}
}
#[cfg(feature = "nightly")]
impl MemRead for Bytes {
fn read_mem(&mut self, _: &mut task::Context<'_>, len: usize) -> Poll<io::Result<Bytes>> {
let n = std::cmp::min(len, self.len());
let ret = self.split_to(n);
Poll::Ready(Ok(ret))
}
}
/*
use std::io;
use std::io::Write;
use super::Decoder;
use super::ChunkedState;
use futures::{Async, Poll};
use bytes::{BytesMut, Bytes};
use crate::mock::AsyncIo;
*/
#[tokio::test]
async fn test_read_chunk_size() {
use std::io::ErrorKind::{InvalidData, InvalidInput, UnexpectedEof};
async fn read(s: &str) -> u64 {
let mut state = ChunkedState::Size;
let rdr = &mut s.as_bytes();
let mut size = 0;
loop {
let result =
futures_util::future::poll_fn(|cx| state.step(cx, rdr, &mut size, &mut None))
.await;
let desc = format!("read_size failed for {:?}", s);
state = result.expect(desc.as_str());
if state == ChunkedState::Body || state == ChunkedState::EndCr {
break;
}
}
size
}
async fn read_err(s: &str, expected_err: io::ErrorKind) {
let mut state = ChunkedState::Size;
let rdr = &mut s.as_bytes();
let mut size = 0;
loop {
let result =
futures_util::future::poll_fn(|cx| state.step(cx, rdr, &mut size, &mut None))
.await;
state = match result {
Ok(s) => s,
Err(e) => {
assert!(
expected_err == e.kind(),
"Reading {:?}, expected {:?}, but got {:?}",
s,
expected_err,
e.kind()
);
return;
}
};
if state == ChunkedState::Body || state == ChunkedState::End {
panic!("Was Ok. Expected Err for {:?}", s);
}
}
}
assert_eq!(1, read("1\r\n").await);
assert_eq!(1, read("01\r\n").await);
assert_eq!(0, read("0\r\n").await);
assert_eq!(0, read("00\r\n").await);
assert_eq!(10, read("A\r\n").await);
assert_eq!(10, read("a\r\n").await);
assert_eq!(255, read("Ff\r\n").await);
assert_eq!(255, read("Ff \r\n").await);
// Missing LF or CRLF
read_err("F\rF", InvalidInput).await;
read_err("F", UnexpectedEof).await;
// Invalid hex digit
read_err("X\r\n", InvalidInput).await;
read_err("1X\r\n", InvalidInput).await;
read_err("-\r\n", InvalidInput).await;
read_err("-1\r\n", InvalidInput).await;
// Acceptable (if not fully valid) extensions do not influence the size
assert_eq!(1, read("1;extension\r\n").await);
assert_eq!(10, read("a;ext name=value\r\n").await);
assert_eq!(1, read("1;extension;extension2\r\n").await);
assert_eq!(1, read("1;;; ;\r\n").await);
assert_eq!(2, read("2; extension...\r\n").await);
assert_eq!(3, read("3 ; extension=123\r\n").await);
assert_eq!(3, read("3 ;\r\n").await);
assert_eq!(3, read("3 ; \r\n").await);
// Invalid extensions cause an error
read_err("1 invalid extension\r\n", InvalidInput).await;
read_err("1 A\r\n", InvalidInput).await;
read_err("1;no CRLF", UnexpectedEof).await;
read_err("1;reject\nnewlines\r\n", InvalidData).await;
// Overflow
read_err("f0000000000000003\r\n", InvalidData).await;
}
#[tokio::test]
async fn test_read_sized_early_eof() {
let mut bytes = &b"foo bar"[..];
let mut decoder = Decoder::length(10);
assert_eq!(decoder.decode_fut(&mut bytes).await.unwrap().len(), 7);
let e = decoder.decode_fut(&mut bytes).await.unwrap_err();
assert_eq!(e.kind(), io::ErrorKind::UnexpectedEof);
}
#[tokio::test]
async fn test_read_chunked_early_eof() {
let mut bytes = &b"\
9\r\n\
foo bar\
"[..];
let mut decoder = Decoder::chunked();
assert_eq!(decoder.decode_fut(&mut bytes).await.unwrap().len(), 7);
let e = decoder.decode_fut(&mut bytes).await.unwrap_err();
assert_eq!(e.kind(), io::ErrorKind::UnexpectedEof);
}
#[tokio::test]
async fn test_read_chunked_single_read() {
let mut mock_buf = &b"10\r\n1234567890abcdef\r\n0\r\n"[..];
let buf = Decoder::chunked()
.decode_fut(&mut mock_buf)
.await
.expect("decode");
assert_eq!(16, buf.len());
let result = String::from_utf8(buf.as_ref().to_vec()).expect("decode String");
assert_eq!("1234567890abcdef", &result);
}
#[tokio::test]
async fn test_read_chunked_trailer_with_missing_lf() {
let mut mock_buf = &b"10\r\n1234567890abcdef\r\n0\r\nbad\r\r\n"[..];
let mut decoder = Decoder::chunked();
decoder.decode_fut(&mut mock_buf).await.expect("decode");
let e = decoder.decode_fut(&mut mock_buf).await.unwrap_err();
assert_eq!(e.kind(), io::ErrorKind::InvalidInput);
}
#[tokio::test]
async fn test_read_chunked_after_eof() {
let mut mock_buf = &b"10\r\n1234567890abcdef\r\n0\r\n\r\n"[..];
let mut decoder = Decoder::chunked();
// normal read
let buf = decoder.decode_fut(&mut mock_buf).await.unwrap();
assert_eq!(16, buf.len());
let result = String::from_utf8(buf.as_ref().to_vec()).expect("decode String");
assert_eq!("1234567890abcdef", &result);
// eof read
let buf = decoder.decode_fut(&mut mock_buf).await.expect("decode");
assert_eq!(0, buf.len());
// ensure read after eof also returns eof
let buf = decoder.decode_fut(&mut mock_buf).await.expect("decode");
assert_eq!(0, buf.len());
}
// perform an async read using a custom buffer size and causing a blocking
// read at the specified byte
async fn read_async(mut decoder: Decoder, content: &[u8], block_at: usize) -> String {
let mut outs = Vec::new();
let mut ins = if block_at == 0 {
tokio_test::io::Builder::new()
.wait(Duration::from_millis(10))
.read(content)
.build()
} else {
tokio_test::io::Builder::new()
.read(&content[..block_at])
.wait(Duration::from_millis(10))
.read(&content[block_at..])
.build()
};
let mut ins = &mut ins as &mut (dyn AsyncRead + Unpin);
loop {
let buf = decoder
.decode_fut(&mut ins)
.await
.expect("unexpected decode error");
if buf.is_empty() {
break; // eof
}
outs.extend(buf.as_ref());
}
String::from_utf8(outs).expect("decode String")
}
// iterate over the different ways that this async read could go.
// tests blocking a read at each byte along the content - The shotgun approach
async fn all_async_cases(content: &str, expected: &str, decoder: Decoder) {
let content_len = content.len();
for block_at in 0..content_len {
let actual = read_async(decoder.clone(), content.as_bytes(), block_at).await;
assert_eq!(expected, &actual) //, "Failed async. Blocking at {}", block_at);
}
}
#[tokio::test]
async fn test_read_length_async() {
let content = "foobar";
all_async_cases(content, content, Decoder::length(content.len() as u64)).await;
}
#[tokio::test]
async fn test_read_chunked_async() {
let content = "3\r\nfoo\r\n3\r\nbar\r\n0\r\n\r\n";
let expected = "foobar";
all_async_cases(content, expected, Decoder::chunked()).await;
}
#[tokio::test]
async fn test_read_eof_async() {
let content = "foobar";
all_async_cases(content, content, Decoder::eof()).await;
}
#[cfg(feature = "nightly")]
#[bench]
fn bench_decode_chunked_1kb(b: &mut test::Bencher) {
let rt = new_runtime();
const LEN: usize = 1024;
let mut vec = Vec::new();
vec.extend(format!("{:x}\r\n", LEN).as_bytes());
vec.extend(&[0; LEN][..]);
vec.extend(b"\r\n");
let content = Bytes::from(vec);
b.bytes = LEN as u64;
b.iter(|| {
let mut decoder = Decoder::chunked();
rt.block_on(async {
let mut raw = content.clone();
let chunk = decoder.decode_fut(&mut raw).await.unwrap();
assert_eq!(chunk.len(), LEN);
});
});
}
#[cfg(feature = "nightly")]
#[bench]
fn bench_decode_length_1kb(b: &mut test::Bencher) {
let rt = new_runtime();
const LEN: usize = 1024;
let content = Bytes::from(&[0; LEN][..]);
b.bytes = LEN as u64;
b.iter(|| {
let mut decoder = Decoder::length(LEN as u64);
rt.block_on(async {
let mut raw = content.clone();
let chunk = decoder.decode_fut(&mut raw).await.unwrap();
assert_eq!(chunk.len(), LEN);
});
});
}
#[cfg(feature = "nightly")]
fn new_runtime() -> tokio::runtime::Runtime {
tokio::runtime::Builder::new_current_thread()
.enable_all()
.build()
.expect("rt build")
}
}