File size: 5,259 Bytes
d90101d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 | #[cfg(not(feature = "std"))]
use alloc::{
string::{FromUtf8Error, String},
vec::Vec,
};
use core::pin::Pin;
#[cfg(feature = "std")]
use std::string::FromUtf8Error;
use futures_core::stream::Stream;
use futures_core::task::{Context, Poll};
use pin_project_lite::pin_project;
pin_project! {
pub struct Utf8Stream<S> {
#[pin]
stream: S,
buffer: Vec<u8>,
terminated: bool,
}
}
impl<S> Utf8Stream<S> {
pub fn new(stream: S) -> Self {
Self { stream, buffer: Vec::new(), terminated: false }
}
}
#[derive(Debug, PartialEq)]
pub enum Utf8StreamError<E> {
Utf8(FromUtf8Error),
Transport(E),
}
impl<E> From<FromUtf8Error> for Utf8StreamError<E> {
fn from(err: FromUtf8Error) -> Self {
Self::Utf8(err)
}
}
impl<S, B, E> Stream for Utf8Stream<S>
where
S: Stream<Item = Result<B, E>>,
B: AsRef<[u8]>,
{
type Item = Result<String, Utf8StreamError<E>>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
let this = self.project();
if *this.terminated {
return Poll::Ready(None);
}
match this.stream.poll_next(cx) {
Poll::Ready(Some(Ok(bytes))) => {
this.buffer.extend_from_slice(bytes.as_ref());
let bytes = core::mem::take(this.buffer);
match String::from_utf8(bytes) {
Ok(string) => Poll::Ready(Some(Ok(string))),
Err(err) => {
let valid_size = err.utf8_error().valid_up_to();
let mut bytes = err.into_bytes();
let rem = bytes.split_off(valid_size);
*this.buffer = rem;
Poll::Ready(Some(Ok(unsafe { String::from_utf8_unchecked(bytes) })))
}
}
}
Poll::Ready(Some(Err(err))) => Poll::Ready(Some(Err(Utf8StreamError::Transport(err)))),
Poll::Ready(None) => {
*this.terminated = true;
if this.buffer.is_empty() {
Poll::Ready(None)
} else {
Poll::Ready(Some(
String::from_utf8(core::mem::take(this.buffer))
.map_err(Utf8StreamError::Utf8),
))
}
}
Poll::Pending => Poll::Pending,
}
}
}
#[cfg(test)]
mod tests {
use futures::prelude::*;
use super::*;
#[tokio::test]
async fn valid_streams() {
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![Ok::<_, ()>(b"Hello, world!")]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec!["Hello, world!"]
);
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![Ok::<_, ()>("Hello, world!")]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec!["Hello, world!"]
);
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![Ok::<_, ()>("")]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec![""]
);
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![
Ok::<_, ()>("Hello"),
Ok::<_, ()>(", world!")
]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec!["Hello", ", world!"]
);
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![Ok::<_, ()>(vec![
240, 159, 145, 141
]),]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec!["👍"]
);
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![
Ok::<_, ()>(vec![240, 159]),
Ok::<_, ()>(vec![145, 141])
]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec!["", "👍"]
);
assert_eq!(
Utf8Stream::new(futures::stream::iter(vec![
Ok::<_, ()>(vec![240, 159]),
Ok::<_, ()>(vec![145, 141, 240, 159, 145, 141])
]))
.try_collect::<Vec<_>>()
.await
.unwrap(),
vec!["", "👍👍"]
);
}
#[tokio::test]
async fn invalid_streams() {
let results = Utf8Stream::new(futures::stream::iter(vec![Ok::<_, ()>(vec![240, 159])]))
.collect::<Vec<_>>()
.await;
assert_eq!(results.len(), 2);
assert_eq!(results[0], Ok("".to_string()));
assert!(matches!(results[1], Err(Utf8StreamError::Utf8(_))));
let results = Utf8Stream::new(futures::stream::iter(vec![
Ok::<_, ()>(vec![240, 159]),
Ok::<_, ()>(vec![145, 141, 240, 159, 145]),
]))
.collect::<Vec<_>>()
.await;
assert_eq!(results.len(), 3);
assert_eq!(results[0], Ok("".to_string()));
assert_eq!(results[1], Ok("👍".to_string()));
assert!(matches!(results[2], Err(Utf8StreamError::Utf8(_))));
}
}
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