use std::error::Error;
use std::future::Future;
use std::io::{self, Write};
use std::pin::Pin;
use std::task::{Context, Poll};
use brotli2::write::BrotliEncoder;
use bytes::Bytes;
use flate2::write::{GzEncoder, ZlibEncoder};
use futures::ready;
use crate::http::body::{Body, BodySize, MessageBody, ResponseBody};
use crate::http::header::{ContentEncoding, HeaderValue, CONTENT_ENCODING};
use crate::http::{ResponseHead, StatusCode};
use crate::rt::task::{spawn_blocking, JoinHandle};
use super::Writer;
const INPLACE: usize = 1024;
pub struct Encoder<B> {
eof: bool,
body: EncoderBody<B>,
encoder: Option<ContentEncoder>,
fut: Option<JoinHandle<Result<ContentEncoder, io::Error>>>,
}
impl<B: MessageBody + 'static> Encoder<B> {
pub fn response(
encoding: ContentEncoding,
head: &mut ResponseHead,
body: ResponseBody<B>,
) -> ResponseBody<B> {
let can_encode = ContentEncoder::can_encode(encoding)
&& !(head.headers().contains_key(&CONTENT_ENCODING)
|| head.status == StatusCode::SWITCHING_PROTOCOLS
|| head.status == StatusCode::NO_CONTENT
|| encoding == ContentEncoding::Identity
|| encoding == ContentEncoding::Auto);
if !can_encode {
body
} else {
let body = match body {
ResponseBody::Other(b) => match b {
Body::None => return ResponseBody::Other(Body::None),
Body::Empty => return ResponseBody::Other(Body::Empty),
Body::Bytes(buf) => EncoderBody::Bytes(buf),
Body::Message(stream) => EncoderBody::BoxedStream(stream),
},
ResponseBody::Body(stream) => EncoderBody::Stream(stream),
};
let encoder = ContentEncoder::encoder(encoding).unwrap();
update_head(encoding, head);
head.no_chunking(false);
ResponseBody::Other(Body::from_message(Encoder {
body,
eof: false,
fut: None,
encoder: Some(encoder),
}))
}
}
}
enum EncoderBody<B> {
Bytes(Bytes),
Stream(B),
BoxedStream(Box<dyn MessageBody>),
}
impl<B: MessageBody> MessageBody for Encoder<B> {
fn size(&self) -> BodySize {
if self.encoder.is_none() {
match self.body {
EncoderBody::Bytes(ref b) => b.size(),
EncoderBody::Stream(ref b) => b.size(),
EncoderBody::BoxedStream(ref b) => b.size(),
}
} else {
BodySize::Stream
}
}
fn poll_next_chunk(
&mut self,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Bytes, Box<dyn Error>>>> {
loop {
if self.eof {
return Poll::Ready(None);
}
if let Some(ref mut fut) = self.fut {
let mut encoder = match ready!(Pin::new(fut).poll(cx)) {
Ok(Ok(item)) => item,
Ok(Err(e)) => return Poll::Ready(Some(Err(Box::new(e)))),
Err(_) => {
return Poll::Ready(Some(Err(Box::new(io::Error::new(
io::ErrorKind::Other,
"Canceled",
)))));
}
};
let chunk = encoder.take();
self.encoder = Some(encoder);
self.fut.take();
if !chunk.is_empty() {
return Poll::Ready(Some(Ok(chunk)));
}
}
let result = match self.body {
EncoderBody::Bytes(ref mut b) => {
if b.is_empty() {
Poll::Ready(None)
} else {
Poll::Ready(Some(Ok(std::mem::take(b))))
}
}
EncoderBody::Stream(ref mut b) => b.poll_next_chunk(cx),
EncoderBody::BoxedStream(ref mut b) => b.poll_next_chunk(cx),
};
match result {
Poll::Ready(Some(Ok(chunk))) => {
if let Some(mut encoder) = self.encoder.take() {
if chunk.len() < INPLACE {
encoder.write(&chunk)?;
let chunk = encoder.take();
self.encoder = Some(encoder);
if !chunk.is_empty() {
return Poll::Ready(Some(Ok(chunk)));
}
} else {
self.fut = Some(spawn_blocking(move || {
encoder.write(&chunk)?;
Ok(encoder)
}));
}
} else {
return Poll::Ready(Some(Ok(chunk)));
}
}
Poll::Ready(None) => {
if let Some(encoder) = self.encoder.take() {
let chunk = encoder.finish()?;
if chunk.is_empty() {
return Poll::Ready(None);
} else {
self.eof = true;
return Poll::Ready(Some(Ok(chunk)));
}
} else {
return Poll::Ready(None);
}
}
val => return val,
}
}
}
}
fn update_head(encoding: ContentEncoding, head: &mut ResponseHead) {
head.headers_mut().insert(
CONTENT_ENCODING,
HeaderValue::from_static(encoding.as_str()),
);
}
enum ContentEncoder {
Deflate(ZlibEncoder<Writer>),
Gzip(GzEncoder<Writer>),
Br(BrotliEncoder<Writer>),
}
impl ContentEncoder {
fn can_encode(encoding: ContentEncoding) -> bool {
match encoding {
ContentEncoding::Deflate | ContentEncoding::Gzip | ContentEncoding::Br => {
true
}
_ => false,
}
}
fn encoder(encoding: ContentEncoding) -> Option<Self> {
match encoding {
ContentEncoding::Deflate => Some(ContentEncoder::Deflate(ZlibEncoder::new(
Writer::new(),
flate2::Compression::fast(),
))),
ContentEncoding::Gzip => Some(ContentEncoder::Gzip(GzEncoder::new(
Writer::new(),
flate2::Compression::fast(),
))),
ContentEncoding::Br => {
Some(ContentEncoder::Br(BrotliEncoder::new(Writer::new(), 3)))
}
_ => None,
}
}
fn take(&mut self) -> Bytes {
match *self {
ContentEncoder::Br(ref mut encoder) => encoder.get_mut().take(),
ContentEncoder::Deflate(ref mut encoder) => encoder.get_mut().take(),
ContentEncoder::Gzip(ref mut encoder) => encoder.get_mut().take(),
}
}
fn finish(self) -> Result<Bytes, io::Error> {
match self {
ContentEncoder::Br(encoder) => match encoder.finish() {
Ok(writer) => Ok(writer.buf.freeze()),
Err(err) => Err(err),
},
ContentEncoder::Gzip(encoder) => match encoder.finish() {
Ok(writer) => Ok(writer.buf.freeze()),
Err(err) => Err(err),
},
ContentEncoder::Deflate(encoder) => match encoder.finish() {
Ok(writer) => Ok(writer.buf.freeze()),
Err(err) => Err(err),
},
}
}
fn write(&mut self, data: &[u8]) -> Result<(), io::Error> {
match *self {
ContentEncoder::Br(ref mut encoder) => match encoder.write_all(data) {
Ok(_) => Ok(()),
Err(err) => {
trace!("Error decoding br encoding: {}", err);
Err(err)
}
},
ContentEncoder::Gzip(ref mut encoder) => match encoder.write_all(data) {
Ok(_) => Ok(()),
Err(err) => {
trace!("Error decoding gzip encoding: {}", err);
Err(err)
}
},
ContentEncoder::Deflate(ref mut encoder) => match encoder.write_all(data) {
Ok(_) => Ok(()),
Err(err) => {
trace!("Error decoding deflate encoding: {}", err);
Err(err)
}
},
}
}
}