tower_async/util/
map_err.rs

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

tower_async/util/
map_err.rs
