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https://github.com/tokio-rs/tokio.git
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cfc15617a5
Related to #1318, Tokio APIs that are "less stable" are moved into a new `tokio-util` crate. This crate will mirror `tokio` and provide additional APIs that may require a greater rate of breaking changes. As examples require `tokio-util`, they are moved into a separate crate (`examples`). This has the added advantage of being able to avoid example only dependencies in the `tokio` crate.
97 lines
2.3 KiB
Rust
97 lines
2.3 KiB
Rust
#![warn(rust_2018_idioms)]
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use tokio::prelude::*;
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use tokio_test::assert_ok;
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use tokio_util::codec::{Decoder, Encoder, Framed, FramedParts};
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use bytes::{Buf, BufMut, BytesMut, IntoBuf};
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use std::io::{self, Read};
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use std::pin::Pin;
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use std::task::{Context, Poll};
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const INITIAL_CAPACITY: usize = 8 * 1024;
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/// Encode and decode u32 values.
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struct U32Codec;
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impl Decoder for U32Codec {
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type Item = u32;
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type Error = io::Error;
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fn decode(&mut self, buf: &mut BytesMut) -> io::Result<Option<u32>> {
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if buf.len() < 4 {
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return Ok(None);
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}
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let n = buf.split_to(4).into_buf().get_u32_be();
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Ok(Some(n))
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}
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}
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impl Encoder for U32Codec {
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type Item = u32;
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type Error = io::Error;
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fn encode(&mut self, item: u32, dst: &mut BytesMut) -> io::Result<()> {
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// Reserve space
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dst.reserve(4);
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dst.put_u32_be(item);
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Ok(())
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}
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}
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/// This value should never be used
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struct DontReadIntoThis;
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impl Read for DontReadIntoThis {
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fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
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Err(io::Error::new(
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io::ErrorKind::Other,
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"Read into something you weren't supposed to.",
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))
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}
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}
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impl AsyncRead for DontReadIntoThis {
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fn poll_read(
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self: Pin<&mut Self>,
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_cx: &mut Context<'_>,
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_buf: &mut [u8],
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) -> Poll<io::Result<usize>> {
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unreachable!()
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}
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}
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#[tokio::test]
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async fn can_read_from_existing_buf() {
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let mut parts = FramedParts::new(DontReadIntoThis, U32Codec);
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parts.read_buf = vec![0, 0, 0, 42].into();
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let mut framed = Framed::from_parts(parts);
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let num = assert_ok!(framed.next().await.unwrap());
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assert_eq!(num, 42);
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}
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#[test]
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fn external_buf_grows_to_init() {
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let mut parts = FramedParts::new(DontReadIntoThis, U32Codec);
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parts.read_buf = vec![0, 0, 0, 42].into();
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let framed = Framed::from_parts(parts);
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let FramedParts { read_buf, .. } = framed.into_parts();
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assert_eq!(read_buf.capacity(), INITIAL_CAPACITY);
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}
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#[test]
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fn external_buf_does_not_shrink() {
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let mut parts = FramedParts::new(DontReadIntoThis, U32Codec);
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parts.read_buf = vec![0; INITIAL_CAPACITY * 2].into();
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let framed = Framed::from_parts(parts);
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let FramedParts { read_buf, .. } = framed.into_parts();
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assert_eq!(read_buf.capacity(), INITIAL_CAPACITY * 2);
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}
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