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use std::fmt;
use std::io::IoSlice;
use bytes::buf::{Chain, Take};
use bytes::Buf;
use tracing::trace;
use super::io::WriteBuf;
type StaticBuf = &'static [u8];
/// Encoders to handle different Transfer-Encodings.
#[derive(Debug, Clone, PartialEq)]
pub(crate) struct Encoder {
kind: Kind,
is_last: bool,
}
#[derive(Debug)]
pub(crate) struct EncodedBuf<B> {
kind: BufKind<B>,
}
#[derive(Debug)]
pub(crate) struct NotEof(u64);
#[derive(Debug, PartialEq, Clone)]
enum Kind {
/// An Encoder for when Transfer-Encoding includes `chunked`.
Chunked,
/// An Encoder for when Content-Length is set.
///
/// Enforces that the body is not longer than the Content-Length header.
Length(u64),
/// An Encoder for when neither Content-Length nor Chunked encoding is set.
///
/// This is mostly only used with HTTP/1.0 with a length. This kind requires
/// the connection to be closed when the body is finished.
#[cfg(feature = "server")]
CloseDelimited,
}
#[derive(Debug)]
enum BufKind<B> {
Exact(B),
Limited(Take<B>),
Chunked(Chain<Chain<ChunkSize, B>, StaticBuf>),
ChunkedEnd(StaticBuf),
}
impl Encoder {
fn new(kind: Kind) -> Encoder {
Encoder {
kind,
is_last: false,
}
}
pub(crate) fn chunked() -> Encoder {
Encoder::new(Kind::Chunked)
}
pub(crate) fn length(len: u64) -> Encoder {
Encoder::new(Kind::Length(len))
}
#[cfg(feature = "server")]
pub(crate) fn close_delimited() -> Encoder {
Encoder::new(Kind::CloseDelimited)
}
pub(crate) fn is_eof(&self) -> bool {
matches!(self.kind, Kind::Length(0))
}
#[cfg(feature = "server")]
pub(crate) fn set_last(mut self, is_last: bool) -> Self {
self.is_last = is_last;
self
}
pub(crate) fn is_last(&self) -> bool {
self.is_last
}
pub(crate) fn is_close_delimited(&self) -> bool {
match self.kind {
#[cfg(feature = "server")]
Kind::CloseDelimited => true,
_ => false,
}
}
pub(crate) fn end<B>(&self) -> Result<Option<EncodedBuf<B>>, NotEof> {
match self.kind {
Kind::Length(0) => Ok(None),
Kind::Chunked => Ok(Some(EncodedBuf {
kind: BufKind::ChunkedEnd(b"0\r\n\r\n"),
})),
#[cfg(feature = "server")]
Kind::CloseDelimited => Ok(None),
Kind::Length(n) => Err(NotEof(n)),
}
}
pub(crate) fn encode<B>(&mut self, msg: B) -> EncodedBuf<B>
where
B: Buf,
{
let len = msg.remaining();
debug_assert!(len > 0, "encode() called with empty buf");
let kind = match self.kind {
Kind::Chunked => {
trace!("encoding chunked {}B", len);
let buf = ChunkSize::new(len)
.chain(msg)
.chain(b"\r\n" as &'static [u8]);
BufKind::Chunked(buf)
}
Kind::Length(ref mut remaining) => {
trace!("sized write, len = {}", len);
if len as u64 > *remaining {
let limit = *remaining as usize;
*remaining = 0;
BufKind::Limited(msg.take(limit))
} else {
*remaining -= len as u64;
BufKind::Exact(msg)
}
}
#[cfg(feature = "server")]
Kind::CloseDelimited => {
trace!("close delimited write {}B", len);
BufKind::Exact(msg)
}
};
EncodedBuf { kind }
}
pub(super) fn encode_and_end<B>(&self, msg: B, dst: &mut WriteBuf<EncodedBuf<B>>) -> bool
where
B: Buf,
{
let len = msg.remaining();
debug_assert!(len > 0, "encode() called with empty buf");
match self.kind {
Kind::Chunked => {
trace!("encoding chunked {}B", len);
let buf = ChunkSize::new(len)
.chain(msg)
.chain(b"\r\n0\r\n\r\n" as &'static [u8]);
dst.buffer(buf);
!self.is_last
}
Kind::Length(remaining) => {
use std::cmp::Ordering;
trace!("sized write, len = {}", len);
match (len as u64).cmp(&remaining) {
Ordering::Equal => {
dst.buffer(msg);
!self.is_last
}
Ordering::Greater => {
dst.buffer(msg.take(remaining as usize));
!self.is_last
}
Ordering::Less => {
dst.buffer(msg);
false
}
}
}
#[cfg(feature = "server")]
Kind::CloseDelimited => {
trace!("close delimited write {}B", len);
dst.buffer(msg);
false
}
}
}
/// Encodes the full body, without verifying the remaining length matches.
///
/// This is used in conjunction with HttpBody::__hyper_full_data(), which
/// means we can trust that the buf has the correct size (the buf itself
/// was checked to make the headers).
pub(super) fn danger_full_buf<B>(self, msg: B, dst: &mut WriteBuf<EncodedBuf<B>>)
where
B: Buf,
{
debug_assert!(msg.remaining() > 0, "encode() called with empty buf");
debug_assert!(
match self.kind {
Kind::Length(len) => len == msg.remaining() as u64,
_ => true,
},
"danger_full_buf length mismatches"
);
match self.kind {
Kind::Chunked => {
let len = msg.remaining();
trace!("encoding chunked {}B", len);
let buf = ChunkSize::new(len)
.chain(msg)
.chain(b"\r\n0\r\n\r\n" as &'static [u8]);
dst.buffer(buf);
}
_ => {
dst.buffer(msg);
}
}
}
}
impl<B> Buf for EncodedBuf<B>
where
B: Buf,
{
#[inline]
fn remaining(&self) -> usize {
match self.kind {
BufKind::Exact(ref b) => b.remaining(),
BufKind::Limited(ref b) => b.remaining(),
BufKind::Chunked(ref b) => b.remaining(),
BufKind::ChunkedEnd(ref b) => b.remaining(),
}
}
#[inline]
fn chunk(&self) -> &[u8] {
match self.kind {
BufKind::Exact(ref b) => b.chunk(),
BufKind::Limited(ref b) => b.chunk(),
BufKind::Chunked(ref b) => b.chunk(),
BufKind::ChunkedEnd(ref b) => b.chunk(),
}
}
#[inline]
fn advance(&mut self, cnt: usize) {
match self.kind {
BufKind::Exact(ref mut b) => b.advance(cnt),
BufKind::Limited(ref mut b) => b.advance(cnt),
BufKind::Chunked(ref mut b) => b.advance(cnt),
BufKind::ChunkedEnd(ref mut b) => b.advance(cnt),
}
}
#[inline]
fn chunks_vectored<'t>(&'t self, dst: &mut [IoSlice<'t>]) -> usize {
match self.kind {
BufKind::Exact(ref b) => b.chunks_vectored(dst),
BufKind::Limited(ref b) => b.chunks_vectored(dst),
BufKind::Chunked(ref b) => b.chunks_vectored(dst),
BufKind::ChunkedEnd(ref b) => b.chunks_vectored(dst),
}
}
}
#[cfg(target_pointer_width = "32")]
const USIZE_BYTES: usize = 4;
#[cfg(target_pointer_width = "64")]
const USIZE_BYTES: usize = 8;
// each byte will become 2 hex
const CHUNK_SIZE_MAX_BYTES: usize = USIZE_BYTES * 2;
#[derive(Clone, Copy)]
struct ChunkSize {
bytes: [u8; CHUNK_SIZE_MAX_BYTES + 2],
pos: u8,
len: u8,
}
impl ChunkSize {
fn new(len: usize) -> ChunkSize {
use std::fmt::Write;
let mut size = ChunkSize {
bytes: [0; CHUNK_SIZE_MAX_BYTES + 2],
pos: 0,
len: 0,
};
write!(&mut size, "{:X}\r\n", len).expect("CHUNK_SIZE_MAX_BYTES should fit any usize");
size
}
}
impl Buf for ChunkSize {
#[inline]
fn remaining(&self) -> usize {
(self.len - self.pos).into()
}
#[inline]
fn chunk(&self) -> &[u8] {
&self.bytes[self.pos.into()..self.len.into()]
}
#[inline]
fn advance(&mut self, cnt: usize) {
assert!(cnt <= self.remaining());
self.pos += cnt as u8; // just asserted cnt fits in u8
}
}
impl fmt::Debug for ChunkSize {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ChunkSize")
.field("bytes", &&self.bytes[..self.len.into()])
.field("pos", &self.pos)
.finish()
}
}
impl fmt::Write for ChunkSize {
fn write_str(&mut self, num: &str) -> fmt::Result {
use std::io::Write;
(&mut self.bytes[self.len.into()..])
.write_all(num.as_bytes())
.expect("&mut [u8].write() cannot error");
self.len += num.len() as u8; // safe because bytes is never bigger than 256
Ok(())
}
}
impl<B: Buf> From<B> for EncodedBuf<B> {
fn from(buf: B) -> Self {
EncodedBuf {
kind: BufKind::Exact(buf),
}
}
}
impl<B: Buf> From<Take<B>> for EncodedBuf<B> {
fn from(buf: Take<B>) -> Self {
EncodedBuf {
kind: BufKind::Limited(buf),
}
}
}
impl<B: Buf> From<Chain<Chain<ChunkSize, B>, StaticBuf>> for EncodedBuf<B> {
fn from(buf: Chain<Chain<ChunkSize, B>, StaticBuf>) -> Self {
EncodedBuf {
kind: BufKind::Chunked(buf),
}
}
}
impl fmt::Display for NotEof {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "early end, expected {} more bytes", self.0)
}
}
impl std::error::Error for NotEof {}
#[cfg(test)]
mod tests {
use bytes::BufMut;
use super::super::io::Cursor;
use super::Encoder;
#[test]
fn chunked() {
let mut encoder = Encoder::chunked();
let mut dst = Vec::new();
let msg1 = b"foo bar".as_ref();
let buf1 = encoder.encode(msg1);
dst.put(buf1);
assert_eq!(dst, b"7\r\nfoo bar\r\n");
let msg2 = b"baz quux herp".as_ref();
let buf2 = encoder.encode(msg2);
dst.put(buf2);
assert_eq!(dst, b"7\r\nfoo bar\r\nD\r\nbaz quux herp\r\n");
let end = encoder.end::<Cursor<Vec<u8>>>().unwrap().unwrap();
dst.put(end);
assert_eq!(
dst,
b"7\r\nfoo bar\r\nD\r\nbaz quux herp\r\n0\r\n\r\n".as_ref()
);
}
#[test]
fn length() {
let max_len = 8;
let mut encoder = Encoder::length(max_len as u64);
let mut dst = Vec::new();
let msg1 = b"foo bar".as_ref();
let buf1 = encoder.encode(msg1);
dst.put(buf1);
assert_eq!(dst, b"foo bar");
assert!(!encoder.is_eof());
encoder.end::<()>().unwrap_err();
let msg2 = b"baz".as_ref();
let buf2 = encoder.encode(msg2);
dst.put(buf2);
assert_eq!(dst.len(), max_len);
assert_eq!(dst, b"foo barb");
assert!(encoder.is_eof());
assert!(encoder.end::<()>().unwrap().is_none());
}
#[test]
fn eof() {
let mut encoder = Encoder::close_delimited();
let mut dst = Vec::new();
let msg1 = b"foo bar".as_ref();
let buf1 = encoder.encode(msg1);
dst.put(buf1);
assert_eq!(dst, b"foo bar");
assert!(!encoder.is_eof());
encoder.end::<()>().unwrap();
let msg2 = b"baz".as_ref();
let buf2 = encoder.encode(msg2);
dst.put(buf2);
assert_eq!(dst, b"foo barbaz");
assert!(!encoder.is_eof());
encoder.end::<()>().unwrap();
}
}