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| </pre><pre class="rust"><code><span class="kw">use </span>core::pin::Pin; |
| <span class="kw">use </span>futures_core::ready; |
| <span class="kw">use </span>futures_core::stream::TryStream; |
| <span class="kw">use </span>futures_core::task::{Context, Poll}; |
| <span class="kw">use </span>futures_io::{AsyncBufRead, AsyncRead, AsyncWrite}; |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="kw">use </span>std::cmp; |
| <span class="kw">use </span>std::io::{Error, <span class="prelude-ty">Result</span>}; |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Reader for the [`into_async_read`](super::TryStreamExt::into_async_read) method. |
| </span><span class="attribute">#[derive(Debug)] |
| #[must_use = <span class="string">"readers do nothing unless polled"</span>] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"io"</span>)))] |
| </span><span class="kw">pub struct </span>IntoAsyncRead<St> |
| <span class="kw">where |
| </span>St: TryStream<Error = Error>, |
| St::Ok: AsRef<[u8]>, |
| { |
| <span class="attribute">#[pin] |
| </span>stream: St, |
| state: ReadState<St::Ok>, |
| } |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">enum </span>ReadState<T: AsRef<[u8]>> { |
| Ready { chunk: T, chunk_start: usize }, |
| PendingChunk, |
| Eof, |
| } |
| |
| <span class="kw">impl</span><St> IntoAsyncRead<St> |
| <span class="kw">where |
| </span>St: TryStream<Error = Error>, |
| St::Ok: AsRef<[u8]>, |
| { |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>new(stream: St) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ stream, state: ReadState::PendingChunk } |
| } |
| } |
| |
| <span class="kw">impl</span><St> AsyncRead <span class="kw">for </span>IntoAsyncRead<St> |
| <span class="kw">where |
| </span>St: TryStream<Error = Error>, |
| St::Ok: AsRef<[u8]>, |
| { |
| <span class="kw">fn </span>poll_read( |
| <span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| buf: <span class="kw-2">&mut </span>[u8], |
| ) -> Poll<<span class="prelude-ty">Result</span><usize>> { |
| <span class="kw">let </span><span class="kw-2">mut </span>this = <span class="self">self</span>.project(); |
| |
| <span class="kw">loop </span>{ |
| <span class="kw">match </span>this.state { |
| ReadState::Ready { chunk, chunk_start } => { |
| <span class="kw">let </span>chunk = chunk.as_ref(); |
| <span class="kw">let </span>len = cmp::min(buf.len(), chunk.len() - <span class="kw-2">*</span>chunk_start); |
| |
| buf[..len].copy_from_slice(<span class="kw-2">&</span>chunk[<span class="kw-2">*</span>chunk_start..<span class="kw-2">*</span>chunk_start + len]); |
| <span class="kw-2">*</span>chunk_start += len; |
| |
| <span class="kw">if </span>chunk.len() == <span class="kw-2">*</span>chunk_start { |
| <span class="kw-2">*</span>this.state = ReadState::PendingChunk; |
| } |
| |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(len)); |
| } |
| ReadState::PendingChunk => <span class="kw">match </span><span class="macro">ready!</span>(this.stream.as_mut().try_poll_next(cx)) { |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(chunk)) => { |
| <span class="kw">if </span>!chunk.as_ref().is_empty() { |
| <span class="kw-2">*</span>this.state = ReadState::Ready { chunk, chunk_start: <span class="number">0 </span>}; |
| } |
| } |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(err)) => { |
| <span class="kw-2">*</span>this.state = ReadState::Eof; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(err)); |
| } |
| <span class="prelude-val">None </span>=> { |
| <span class="kw-2">*</span>this.state = ReadState::Eof; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="number">0</span>)); |
| } |
| }, |
| ReadState::Eof => { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="number">0</span>)); |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><St> AsyncWrite <span class="kw">for </span>IntoAsyncRead<St> |
| <span class="kw">where |
| </span>St: TryStream<Error = Error> + AsyncWrite, |
| St::Ok: AsRef<[u8]>, |
| { |
| <span class="kw">fn </span>poll_write(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, buf: <span class="kw-2">&</span>[u8]) -> Poll<<span class="prelude-ty">Result</span><usize>> { |
| <span class="kw">let </span>this = <span class="self">self</span>.project(); |
| this.stream.poll_write(cx, buf) |
| } |
| |
| <span class="kw">fn </span>poll_flush(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><()>> { |
| <span class="kw">let </span>this = <span class="self">self</span>.project(); |
| this.stream.poll_flush(cx) |
| } |
| |
| <span class="kw">fn </span>poll_close(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><()>> { |
| <span class="kw">let </span>this = <span class="self">self</span>.project(); |
| this.stream.poll_close(cx) |
| } |
| } |
| |
| <span class="kw">impl</span><St> AsyncBufRead <span class="kw">for </span>IntoAsyncRead<St> |
| <span class="kw">where |
| </span>St: TryStream<Error = Error>, |
| St::Ok: AsRef<[u8]>, |
| { |
| <span class="kw">fn </span>poll_fill_buf(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><<span class="kw-2">&</span>[u8]>> { |
| <span class="kw">let </span><span class="kw-2">mut </span>this = <span class="self">self</span>.project(); |
| |
| <span class="kw">while let </span>ReadState::PendingChunk = this.state { |
| <span class="kw">match </span><span class="macro">ready!</span>(this.stream.as_mut().try_poll_next(cx)) { |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(chunk)) => { |
| <span class="kw">if </span>!chunk.as_ref().is_empty() { |
| <span class="kw-2">*</span>this.state = ReadState::Ready { chunk, chunk_start: <span class="number">0 </span>}; |
| } |
| } |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(err)) => { |
| <span class="kw-2">*</span>this.state = ReadState::Eof; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(err)); |
| } |
| <span class="prelude-val">None </span>=> { |
| <span class="kw-2">*</span>this.state = ReadState::Eof; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">&</span>[])); |
| } |
| } |
| } |
| |
| <span class="kw">if let </span><span class="kw-2">&mut </span>ReadState::Ready { <span class="kw-2">ref </span>chunk, chunk_start } = this.state { |
| <span class="kw">let </span>chunk = chunk.as_ref(); |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">&</span>chunk[chunk_start..])); |
| } |
| |
| <span class="comment">// To get to this point we must be in ReadState::Eof |
| </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">&</span>[])) |
| } |
| |
| <span class="kw">fn </span>consume(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, amount: usize) { |
| <span class="kw">let </span>this = <span class="self">self</span>.project(); |
| |
| <span class="comment">// https://github.com/rust-lang/futures-rs/pull/1556#discussion_r281644295 |
| </span><span class="kw">if </span>amount == <span class="number">0 </span>{ |
| <span class="kw">return</span>; |
| } |
| <span class="kw">if let </span>ReadState::Ready { chunk, chunk_start } = this.state { |
| <span class="kw-2">*</span>chunk_start += amount; |
| <span class="macro">debug_assert!</span>(<span class="kw-2">*</span>chunk_start <= chunk.as_ref().len()); |
| <span class="kw">if </span><span class="kw-2">*</span>chunk_start >= chunk.as_ref().len() { |
| <span class="kw-2">*</span>this.state = ReadState::PendingChunk; |
| } |
| } <span class="kw">else </span>{ |
| <span class="macro">debug_assert!</span>(<span class="bool-val">false</span>, <span class="string">"Attempted to consume from IntoAsyncRead without chunk"</span>); |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="futures_util" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |