1use std::fmt;
2use std::task::{Context, Poll};
3use tower_layer::Layer;
4use tower_service::Service;
5
6/// Service returned by the [`MapRequest`] combinator.
7///
8/// [`MapRequest`]: crate::util::ServiceExt::map_request
9#[derive(Clone)]
10pub struct MapRequest<S, F> {
11 inner: S,
12 f: F,
13}
14
15impl<S, F> fmt::Debug for MapRequest<S, F>
16where
17 S: fmt::Debug,
18{
19 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
20 f&mut DebugStruct<'_, '_>.debug_struct("MapRequest")
21 .field("inner", &self.inner)
22 .field(name:"f", &format_args!("{}", std::any::type_name::<F>()))
23 .finish()
24 }
25}
26
27impl<S, F> MapRequest<S, F> {
28 /// Creates a new [`MapRequest`] service.
29 pub const fn new(inner: S, f: F) -> Self {
30 MapRequest { inner, f }
31 }
32
33 /// Returns a new [`Layer`] that produces [`MapRequest`] services.
34 ///
35 /// This is a convenience function that simply calls [`MapRequestLayer::new`].
36 ///
37 /// [`Layer`]: tower_layer::Layer
38 pub fn layer(f: F) -> MapRequestLayer<F> {
39 MapRequestLayer { f }
40 }
41}
42
43impl<S, F, R1, R2> Service<R1> for MapRequest<S, F>
44where
45 S: Service<R2>,
46 F: FnMut(R1) -> R2,
47{
48 type Response = S::Response;
49 type Error = S::Error;
50 type Future = S::Future;
51
52 #[inline]
53 fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
54 self.inner.poll_ready(cx)
55 }
56
57 #[inline]
58 fn call(&mut self, request: R1) -> S::Future {
59 self.inner.call((self.f)(request))
60 }
61}
62
63/// A [`Layer`] that produces [`MapRequest`] services.
64///
65/// [`Layer`]: tower_layer::Layer
66#[derive(Clone, Debug)]
67pub struct MapRequestLayer<F> {
68 f: F,
69}
70
71impl<F> MapRequestLayer<F> {
72 /// Creates a new [`MapRequestLayer`].
73 pub const fn new(f: F) -> Self {
74 MapRequestLayer { f }
75 }
76}
77
78impl<S, F> Layer<S> for MapRequestLayer<F>
79where
80 F: Clone,
81{
82 type Service = MapRequest<S, F>;
83
84 fn layer(&self, inner: S) -> Self::Service {
85 MapRequest {
86 f: self.f.clone(),
87 inner,
88 }
89 }
90}
91