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| </pre><pre class="rust"><code><span class="kw">use </span>core::marker::PhantomData; |
| <span class="kw">use </span>core::pin::Pin; |
| |
| <span class="kw">use </span>futures_core::ready; |
| <span class="kw">use </span>futures_core::stream::{FusedStream, Stream, TryStream}; |
| <span class="kw">use </span>futures_core::task::{Context, Poll}; |
| <span class="attribute">#[cfg(feature = <span class="string">"sink"</span>)] |
| </span><span class="kw">use </span>futures_sink::Sink; |
| |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::future::Either; |
| <span class="kw">use </span><span class="kw">crate</span>::stream::stream::flatten_unordered::{ |
| FlattenUnorderedWithFlowController, FlowController, FlowStep, |
| }; |
| <span class="kw">use </span><span class="kw">crate</span>::stream::IntoStream; |
| <span class="kw">use </span><span class="kw">crate</span>::TryStreamExt; |
| |
| <span class="macro">delegate_all!</span>( |
| <span class="doccomment">/// Stream for the [`try_flatten_unordered`](super::TryStreamExt::try_flatten_unordered) method. |
| </span>TryFlattenUnordered<St>( |
| FlattenUnorderedWithFlowController<NestedTryStreamIntoEitherTryStream<St>, PropagateBaseStreamError<St>> |
| ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] |
| + New[ |
| |stream: St, limit: <span class="kw">impl </span>Into<<span class="prelude-ty">Option</span><usize>>| |
| FlattenUnorderedWithFlowController::new( |
| NestedTryStreamIntoEitherTryStream::new(stream), |
| limit.into() |
| ) |
| ] |
| <span class="kw">where |
| </span>St: TryStream, |
| St::Ok: TryStream, |
| St::Ok: Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<St::Error> |
| ); |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Emits either successful streams or single-item streams containing the underlying errors. |
| /// This's a wrapper for `FlattenUnordered` to reuse its logic over `TryStream`. |
| </span><span class="attribute">#[derive(Debug)] |
| #[must_use = <span class="string">"streams do nothing unless polled"</span>] |
| </span><span class="kw">pub struct </span>NestedTryStreamIntoEitherTryStream<St> |
| <span class="kw">where |
| </span>St: TryStream, |
| St::Ok: TryStream, |
| St::Ok: Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<St::Error> |
| { |
| <span class="attribute">#[pin] |
| </span>stream: St |
| } |
| } |
| |
| <span class="kw">impl</span><St> NestedTryStreamIntoEitherTryStream<St> |
| <span class="kw">where |
| </span>St: TryStream, |
| St::Ok: TryStream + Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<St::Error>, |
| { |
| <span class="kw">fn </span>new(stream: St) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ stream } |
| } |
| |
| <span class="macro">delegate_access_inner!</span>(stream, St, ()); |
| } |
| |
| <span class="doccomment">/// Emits a single item immediately, then stream will be terminated. |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">pub struct </span>Single<T>(<span class="prelude-ty">Option</span><T>); |
| |
| <span class="kw">impl</span><T> Single<T> { |
| <span class="doccomment">/// Constructs new `Single` with the given value. |
| </span><span class="kw">fn </span>new(val: T) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>(<span class="prelude-val">Some</span>(val)) |
| } |
| |
| <span class="doccomment">/// Attempts to take inner item immediately. Will always succeed if the stream isn't terminated. |
| </span><span class="kw">fn </span>next_immediate(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><T> { |
| <span class="self">self</span>.<span class="number">0</span>.take() |
| } |
| } |
| |
| <span class="kw">impl</span><T> Unpin <span class="kw">for </span>Single<T> {} |
| |
| <span class="kw">impl</span><T> Stream <span class="kw">for </span>Single<T> { |
| <span class="kw">type </span>Item = T; |
| |
| <span class="kw">fn </span>poll_next(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, <span class="kw">_</span>: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Option</span><<span class="self">Self</span>::Item>> { |
| Poll::Ready(<span class="self">self</span>.<span class="number">0</span>.take()) |
| } |
| |
| <span class="kw">fn </span>size_hint(<span class="kw-2">&</span><span class="self">self</span>) -> (usize, <span class="prelude-ty">Option</span><usize>) { |
| <span class="self">self</span>.<span class="number">0</span>.as_ref().map_or((<span class="number">0</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>)), |<span class="kw">_</span>| (<span class="number">1</span>, <span class="prelude-val">Some</span>(<span class="number">1</span>))) |
| } |
| } |
| |
| <span class="doccomment">/// Immediately propagates errors occurred in the base stream. |
| </span><span class="attribute">#[derive(Debug, Clone, Copy)] |
| </span><span class="kw">pub struct </span>PropagateBaseStreamError<St>(PhantomData<St>); |
| |
| <span class="kw">type </span>BaseStreamItem<St> = <NestedTryStreamIntoEitherTryStream<St> <span class="kw">as </span>Stream>::Item; |
| <span class="kw">type </span>InnerStreamItem<St> = <BaseStreamItem<St> <span class="kw">as </span>Stream>::Item; |
| |
| <span class="kw">impl</span><St> FlowController<BaseStreamItem<St>, InnerStreamItem<St>> <span class="kw">for </span>PropagateBaseStreamError<St> |
| <span class="kw">where |
| </span>St: TryStream, |
| St::Ok: TryStream + Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<St::Error>, |
| { |
| <span class="kw">fn </span>next_step(item: BaseStreamItem<St>) -> FlowStep<BaseStreamItem<St>, InnerStreamItem<St>> { |
| <span class="kw">match </span>item { |
| <span class="comment">// A new successful inner stream received |
| </span>st @ Either::Left(<span class="kw">_</span>) => FlowStep::Continue(st), |
| <span class="comment">// An error encountered |
| </span>Either::Right(<span class="kw-2">mut </span>err) => FlowStep::Return(err.next_immediate().unwrap()), |
| } |
| } |
| } |
| |
| <span class="kw">type </span>SingleStreamResult<St> = Single<<span class="prelude-ty">Result</span><<St <span class="kw">as </span>TryStream>::Ok, <St <span class="kw">as </span>TryStream>::Error>>; |
| |
| <span class="kw">impl</span><St> Stream <span class="kw">for </span>NestedTryStreamIntoEitherTryStream<St> |
| <span class="kw">where |
| </span>St: TryStream, |
| St::Ok: TryStream + Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<St::Error>, |
| { |
| <span class="comment">// Item is either an inner stream or a stream containing a single error. |
| // This will allow using `Either`'s `Stream` implementation as both branches are actually streams of `Result`'s. |
| </span><span class="kw">type </span>Item = Either<IntoStream<St::Ok>, SingleStreamResult<St::Ok>>; |
| |
| <span class="kw">fn </span>poll_next(<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">Option</span><<span class="self">Self</span>::Item>> { |
| <span class="kw">let </span>item = <span class="macro">ready!</span>(<span class="self">self</span>.project().stream.try_poll_next(cx)); |
| |
| <span class="kw">let </span>out = <span class="kw">match </span>item { |
| <span class="prelude-val">Some</span>(res) => <span class="kw">match </span>res { |
| <span class="comment">// Emit successful inner stream as is |
| </span><span class="prelude-val">Ok</span>(stream) => Either::Left(stream.into_stream()), |
| <span class="comment">// Wrap an error into a stream containing a single item |
| </span>err @ <span class="prelude-val">Err</span>(<span class="kw">_</span>) => { |
| <span class="kw">let </span>res = err.map(|<span class="kw">_</span>: St::Ok| <span class="macro">unreachable!</span>()).map_err(Into::into); |
| |
| Either::Right(Single::new(res)) |
| } |
| }, |
| <span class="prelude-val">None </span>=> <span class="kw">return </span>Poll::Ready(<span class="prelude-val">None</span>), |
| }; |
| |
| Poll::Ready(<span class="prelude-val">Some</span>(out)) |
| } |
| } |
| |
| <span class="kw">impl</span><St> FusedStream <span class="kw">for </span>NestedTryStreamIntoEitherTryStream<St> |
| <span class="kw">where |
| </span>St: TryStream + FusedStream, |
| St::Ok: TryStream + Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<St::Error>, |
| { |
| <span class="kw">fn </span>is_terminated(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.stream.is_terminated() |
| } |
| } |
| |
| <span class="comment">// Forwarding impl of Sink from the underlying stream |
| </span><span class="attribute">#[cfg(feature = <span class="string">"sink"</span>)] |
| </span><span class="kw">impl</span><St, Item> Sink<Item> <span class="kw">for </span>NestedTryStreamIntoEitherTryStream<St> |
| <span class="kw">where |
| </span>St: TryStream + Sink<Item>, |
| St::Ok: TryStream + Unpin, |
| <St::Ok <span class="kw">as </span>TryStream>::Error: From<<St <span class="kw">as </span>TryStream>::Error>, |
| { |
| <span class="kw">type </span>Error = <St <span class="kw">as </span>Sink<Item>>::Error; |
| |
| <span class="macro">delegate_sink!</span>(stream, Item); |
| } |
| </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> |
