/rust/registry/src/index.crates.io-1949cf8c6b5b557f/tower-0.5.2/src/util/either.rs

Source
//! Contains [`Either`] and related types and functions.
//!
//! See [`Either`] documentation for more details.

use pin_project_lite::pin_project;
use std::{
    future::Future,
    pin::Pin,
    task::{Context, Poll},
};
use tower_layer::Layer;
use tower_service::Service;

/// Combine two different service types into a single type.
///
/// Both services must be of the same request, response, and error types.
/// [`Either`] is useful for handling conditional branching in service middleware
/// to different inner service types.
#[derive(Clone, Copy, Debug)]
pub enum Either<A, B> {
    #[allow(missing_docs)]
    Left(A),
    #[allow(missing_docs)]
    Right(B),
}

impl<A, B, Request> Service<Request> for Either<A, B>
where
    A: Service<Request>,
    B: Service<Request, Response = A::Response, Error = A::Error>,
{
    type Response = A::Response;
    type Error = A::Error;
    type Future = EitherResponseFuture<A::Future, B::Future>;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        match self {
            Either::Left(service) => service.poll_ready(cx),
            Either::Right(service) => service.poll_ready(cx),
        }
    }

    fn call(&mut self, request: Request) -> Self::Future {
        match self {
            Either::Left(service) => EitherResponseFuture {
                kind: Kind::Left {
                    inner: service.call(request),
                },
            },
            Either::Right(service) => EitherResponseFuture {
                kind: Kind::Right {
                    inner: service.call(request),
                },
            },
        }
    }
}

pin_project! {
    /// Response future for [`Either`].
    pub struct EitherResponseFuture<A, B> {
        #[pin]
        kind: Kind<A, B>
    }
}

pin_project! {
    #[project = KindProj]
    enum Kind<A, B> {
        Left { #[pin] inner: A },
        Right { #[pin] inner: B },
    }
}

impl<A, B> Future for EitherResponseFuture<A, B>
where
    A: Future,
    B: Future<Output = A::Output>,
{
    type Output = A::Output;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        match self.project().kind.project() {
            KindProj::Left { inner } => inner.poll(cx),
            KindProj::Right { inner } => inner.poll(cx),
        }
    }
}

impl<S, A, B> Layer<S> for Either<A, B>
where
    A: Layer<S>,
    B: Layer<S>,
{
    type Service = Either<A::Service, B::Service>;

    fn layer(&self, inner: S) -> Self::Service {
        match self {
            Either::Left(layer) => Either::Left(layer.layer(inner)),
            Either::Right(layer) => Either::Right(layer.layer(inner)),
        }
    }
}

Line	Count	Source
1		//! Contains [`Either`] and related types and functions.
2		//!
3		//! See [`Either`] documentation for more details.
4
5		use pin_project_lite::pin_project;
6		use std::{
7		future::Future,
8		pin::Pin,
9		task::{Context, Poll},
10		};
11		use tower_layer::Layer;
12		use tower_service::Service;
13
14		/// Combine two different service types into a single type.
15		///
16		/// Both services must be of the same request, response, and error types.
17		/// [`Either`] is useful for handling conditional branching in service middleware
18		/// to different inner service types.
19		#[derive(Clone, Copy, Debug)]
20		pub enum Either<A, B> {
21		#[allow(missing_docs)]
22		Left(A),
23		#[allow(missing_docs)]
24		Right(B),
25		}
26
27		impl<A, B, Request> Service<Request> for Either<A, B>
28		where
29		A: Service<Request>,
30		B: Service<Request, Response = A::Response, Error = A::Error>,
31		{
32		type Response = A::Response;
33		type Error = A::Error;
34		type Future = EitherResponseFuture<A::Future, B::Future>;
35
36	0	fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
37	0	match self {
38	0	Either::Left(service) => service.poll_ready(cx),
39	0	Either::Right(service) => service.poll_ready(cx),
40		}
41	0	} Unexecuted instantiation: <tower::util::either::Either<tower::limit::concurrency::service::ConcurrencyLimit<tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>>, tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::poll_ready Unexecuted instantiation: <tower::util::either::Either<tower::limit::concurrency::service::ConcurrencyLimit<tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>>, tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::poll_ready Unexecuted instantiation: <tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::poll_ready Unexecuted instantiation: <tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::poll_ready Unexecuted instantiation: <tower::util::either::Either<_, _> as tower_service::Service<_>>::poll_ready
42
43	0	fn call(&mut self, request: Request) -> Self::Future {
44	0	match self {
45	0	Either::Left(service) => EitherResponseFuture {
46	0	kind: Kind::Left {
47	0	inner: service.call(request),
48	0	},
49	0	},
50	0	Either::Right(service) => EitherResponseFuture {
51	0	kind: Kind::Right {
52	0	inner: service.call(request),
53	0	},
54	0	},
55		}
56	0	} Unexecuted instantiation: <tower::util::either::Either<tower::limit::concurrency::service::ConcurrencyLimit<tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>>, tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::call Unexecuted instantiation: <tower::util::either::Either<tower::limit::concurrency::service::ConcurrencyLimit<tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>>, tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::call Unexecuted instantiation: <tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::call Unexecuted instantiation: <tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>> as tower_service::Service<http::request::Request<tonic::body::Body>>>::call Unexecuted instantiation: <tower::util::either::Either<_, _> as tower_service::Service<_>>::call
57		}
58
59		pin_project! {
60		/// Response future for [`Either`].
61		pub struct EitherResponseFuture<A, B> {
62		#[pin]
63		kind: Kind<A, B>
64		}
65		}
66
67		pin_project! {
68		#[project = KindProj]
69		enum Kind<A, B> {
70		Left { #[pin] inner: A },
71		Right { #[pin] inner: B },
72		}
73		}
74
75		impl<A, B> Future for EitherResponseFuture<A, B>
76		where
77		A: Future,
78		B: Future<Output = A::Output>,
79		{
80		type Output = A::Output;
81
82	0	fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
83	0	match self.project().kind.project() {
84	0	KindProj::Left { inner } => inner.poll(cx),
85	0	KindProj::Right { inner } => inner.poll(cx),
86		}
87	0	} Unexecuted instantiation: <tower::util::either::EitherResponseFuture<tower::limit::concurrency::future::ResponseFuture<tower::util::either::EitherResponseFuture<tonic::transport::channel::service::reconnect::ResponseFuture<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = core::result::Result<http::response::Response<tonic::body::Body>, alloc::boxed::Box<dyn core::error::Error + core::marker::Send + core::marker::Sync>>> + core::marker::Send>>>, tonic::transport::channel::service::reconnect::ResponseFuture<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = core::result::Result<http::response::Response<tonic::body::Body>, alloc::boxed::Box<dyn core::error::Error + core::marker::Send + core::marker::Sync>>> + core::marker::Send>>>>>, tower::util::either::EitherResponseFuture<tonic::transport::channel::service::reconnect::ResponseFuture<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = core::result::Result<http::response::Response<tonic::body::Body>, alloc::boxed::Box<dyn core::error::Error + core::marker::Send + core::marker::Sync>>> + core::marker::Send>>>, tonic::transport::channel::service::reconnect::ResponseFuture<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = core::result::Result<http::response::Response<tonic::body::Body>, alloc::boxed::Box<dyn core::error::Error + core::marker::Send + core::marker::Sync>>> + core::marker::Send>>>>> as core::future::future::Future>::poll Unexecuted instantiation: <tower::util::either::EitherResponseFuture<tonic::transport::channel::service::reconnect::ResponseFuture<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = core::result::Result<http::response::Response<tonic::body::Body>, alloc::boxed::Box<dyn core::error::Error + core::marker::Send + core::marker::Sync>>> + core::marker::Send>>>, tonic::transport::channel::service::reconnect::ResponseFuture<core::pin::Pin<alloc::boxed::Box<dyn core::future::future::Future<Output = core::result::Result<http::response::Response<tonic::body::Body>, alloc::boxed::Box<dyn core::error::Error + core::marker::Send + core::marker::Sync>>> + core::marker::Send>>>> as core::future::future::Future>::poll Unexecuted instantiation: <tower::util::either::EitherResponseFuture<_, _> as core::future::future::Future>::poll
88		}
89
90		impl<S, A, B> Layer<S> for Either<A, B>
91		where
92		A: Layer<S>,
93		B: Layer<S>,
94		{
95		type Service = Either<A::Service, B::Service>;
96
97	0	fn layer(&self, inner: S) -> Self::Service {
98	0	match self {
99	0	Either::Left(layer) => Either::Left(layer.layer(inner)),
100	0	Either::Right(layer) => Either::Right(layer.layer(inner)),
101		}
102	0	} Unexecuted instantiation: <tower::util::either::Either<tower::limit::concurrency::layer::ConcurrencyLimitLayer, tower_layer::identity::Identity> as tower_layer::Layer<tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>>>::layer Unexecuted instantiation: <tower::util::either::Either<tower::limit::concurrency::layer::ConcurrencyLimitLayer, tower_layer::identity::Identity> as tower_layer::Layer<tower::util::either::Either<tower::limit::rate::service::RateLimit<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>, tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>>>::layer Unexecuted instantiation: <tower::util::either::Either<tower::limit::rate::layer::RateLimitLayer, tower_layer::identity::Identity> as tower_layer::Layer<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<tonic::transport::channel::uds_connector::UdsConnector>>, http::uri::Uri>>>::layer Unexecuted instantiation: <tower::util::either::Either<tower::limit::rate::layer::RateLimitLayer, tower_layer::identity::Identity> as tower_layer::Layer<tonic::transport::channel::service::reconnect::Reconnect<tonic::transport::channel::service::connection::MakeSendRequestService<tonic::transport::channel::service::connector::Connector<hyper_util::client::legacy::connect::http::HttpConnector>>, http::uri::Uri>>>::layer Unexecuted instantiation: <tower::util::either::Either<_, _> as tower_layer::Layer<_>>::layer
103		}

Coverage Report

Created: 2026-03-11 07:34