131 lines
3.3 KiB
Rust
131 lines
3.3 KiB
Rust
use futures_core::TryFuture;
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use futures_util::{future, TryFutureExt};
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use std::fmt;
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use std::future::Future;
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use std::pin::Pin;
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use std::task::{Context, Poll};
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use tower_layer::Layer;
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use tower_service::Service;
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/// Service returned by the [`and_then`] combinator.
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///
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/// [`and_then`]: crate::util::ServiceExt::and_then
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#[derive(Clone)]
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pub struct AndThen<S, F> {
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inner: S,
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f: F,
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}
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impl<S, F> fmt::Debug for AndThen<S, F>
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where
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S: fmt::Debug,
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{
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_struct("AndThen")
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.field("inner", &self.inner)
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.field("f", &format_args!("{}", std::any::type_name::<F>()))
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.finish()
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}
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}
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pin_project_lite::pin_project! {
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/// Response future from [`AndThen`] services.
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///
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/// [`AndThen`]: crate::util::AndThen
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pub struct AndThenFuture<F1, F2: TryFuture, N> {
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#[pin]
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inner: future::AndThen<future::ErrInto<F1, F2::Error>, F2, N>,
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}
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}
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impl<F1, F2: TryFuture, N> AndThenFuture<F1, F2, N> {
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pub(crate) fn new(inner: future::AndThen<future::ErrInto<F1, F2::Error>, F2, N>) -> Self {
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Self { inner }
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}
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}
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impl<F1, F2: TryFuture, N> std::fmt::Debug for AndThenFuture<F1, F2, N> {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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f.debug_tuple("AndThenFuture")
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.field(&format_args!("..."))
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.finish()
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}
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}
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impl<F1, F2: TryFuture, N> Future for AndThenFuture<F1, F2, N>
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where
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future::AndThen<future::ErrInto<F1, F2::Error>, F2, N>: Future,
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{
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type Output = <future::AndThen<future::ErrInto<F1, F2::Error>, F2, N> as Future>::Output;
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#[inline]
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fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
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self.project().inner.poll(cx)
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}
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}
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/// A [`Layer`] that produces a [`AndThen`] service.
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///
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/// [`Layer`]: tower_layer::Layer
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#[derive(Clone, Debug)]
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pub struct AndThenLayer<F> {
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f: F,
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}
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impl<S, F> AndThen<S, F> {
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/// Creates a new `AndThen` service.
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pub const fn new(inner: S, f: F) -> Self {
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AndThen { f, inner }
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}
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/// Returns a new [`Layer`] that produces [`AndThen`] services.
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///
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/// This is a convenience function that simply calls [`AndThenLayer::new`].
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///
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/// [`Layer`]: tower_layer::Layer
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pub fn layer(f: F) -> AndThenLayer<F> {
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AndThenLayer { f }
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}
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}
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impl<S, F, Request, Fut> Service<Request> for AndThen<S, F>
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where
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S: Service<Request>,
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S::Error: Into<Fut::Error>,
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F: FnOnce(S::Response) -> Fut + Clone,
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Fut: TryFuture,
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{
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type Response = Fut::Ok;
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type Error = Fut::Error;
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type Future = AndThenFuture<S::Future, Fut, F>;
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fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
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self.inner.poll_ready(cx).map_err(Into::into)
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}
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fn call(&mut self, request: Request) -> Self::Future {
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AndThenFuture::new(self.inner.call(request).err_into().and_then(self.f.clone()))
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}
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}
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impl<F> AndThenLayer<F> {
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/// Creates a new [`AndThenLayer`] layer.
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pub const fn new(f: F) -> Self {
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AndThenLayer { f }
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}
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}
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impl<S, F> Layer<S> for AndThenLayer<F>
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where
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F: Clone,
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{
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type Service = AndThen<S, F>;
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fn layer(&self, inner: S) -> Self::Service {
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AndThen {
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f: self.f.clone(),
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inner,
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}
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}
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}
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