use std::rc::Rc; use std::sync::Arc; use futures::{Future, IntoFuture, Poll}; pub use void::Void; mod and_then; mod and_then_apply; mod and_then_apply_fn; mod apply; pub mod blank; pub mod boxed; mod cell; mod fn_service; mod fn_transform; mod from_err; mod map; mod map_err; mod map_init_err; mod then; mod transform; mod transform_map_init_err; pub use self::and_then::{AndThen, AndThenNewService}; pub use self::and_then_apply::AndThenTransform; use self::and_then_apply_fn::{AndThenApply, AndThenApplyNewService}; pub use self::apply::{Apply, ApplyNewService}; pub use self::fn_service::{fn_cfg_factory, fn_factory, fn_service, FnService}; pub use self::fn_transform::FnTransform; pub use self::from_err::{FromErr, FromErrNewService}; pub use self::map::{Map, MapNewService}; pub use self::map_err::{MapErr, MapErrNewService}; pub use self::map_init_err::MapInitErr; pub use self::then::{Then, ThenNewService}; pub use self::transform::{IntoTransform, Transform}; /// An asynchronous function from `Request` to a `Response`. pub trait Service { /// Requests handled by the service. type Request; /// Responses given by the service. type Response; /// Errors produced by the service. type Error; /// The future response value. type Future: Future<Item = Self::Response, Error = Self::Error>; /// Returns `Ready` when the service is able to process requests. /// /// If the service is at capacity, then `NotReady` is returned and the task /// is notified when the service becomes ready again. This function is /// expected to be called while on a task. /// /// This is a **best effort** implementation. False positives are permitted. /// It is permitted for the service to return `Ready` from a `poll_ready` /// call and the next invocation of `call` results in an error. fn poll_ready(&mut self) -> Poll<(), Self::Error>; /// Process the request and return the response asynchronously. /// /// This function is expected to be callable off task. As such, /// implementations should take care to not call `poll_ready`. If the /// service is at capacity and the request is unable to be handled, the /// returned `Future` should resolve to an error. /// /// Calling `call` without calling `poll_ready` is permitted. The /// implementation must be resilient to this fact. fn call(&mut self, req: Self::Request) -> Self::Future; } /// An extension trait for `Service`s that provides a variety of convenient /// adapters pub trait ServiceExt: Service { /// Apply function to specified service and use it as a next service in /// chain. fn apply_fn<F, B, B1, Out>(self, service: B1, f: F) -> AndThenApply<Self, B, F, Out> where Self: Sized, F: FnMut(Self::Response, &mut B) -> Out, Out: IntoFuture, Out::Error: Into<Self::Error>, B: Service<Error = Self::Error>, B1: IntoService<B>, { AndThenApply::new(self, service, f) } /// Call another service after call to this one has resolved successfully. /// /// This function can be used to chain two services together and ensure that /// the second service isn't called until call to the fist service have /// finished. Result of the call to the first service is used as an /// input parameter for the second service's call. /// /// Note that this function consumes the receiving service and returns a /// wrapped version of it. fn and_then<F, B>(self, service: F) -> AndThen<Self, B> where Self: Sized, F: IntoService<B>, B: Service<Request = Self::Response, Error = Self::Error>, { AndThen::new(self, service.into_service()) } /// Map this service's error to any error implementing `From` for /// this service`s `Error`. /// /// Note that this function consumes the receiving service and returns a /// wrapped version of it. fn from_err<E>(self) -> FromErr<Self, E> where Self: Sized, E: From<Self::Error>, { FromErr::new(self) } /// Chain on a computation for when a call to the service finished, /// passing the result of the call to the next service `B`. /// /// Note that this function consumes the receiving service and returns a /// wrapped version of it. fn then<B>(self, service: B) -> Then<Self, B> where Self: Sized, B: Service<Request = Result<Self::Response, Self::Error>, Error = Self::Error>, { Then::new(self, service) } /// Map this service's output to a different type, returning a new service /// of the resulting type. /// /// This function is similar to the `Option::map` or `Iterator::map` where /// it will change the type of the underlying service. /// /// Note that this function consumes the receiving service and returns a /// wrapped version of it, similar to the existing `map` methods in the /// standard library. fn map<F, R>(self, f: F) -> Map<Self, F, R> where Self: Sized, F: FnMut(Self::Response) -> R, { Map::new(self, f) } /// Map this service's error to a different error, returning a new service. /// /// This function is similar to the `Result::map_err` where it will change /// the error type of the underlying service. This is useful for example to /// ensure that services have the same error type. /// /// Note that this function consumes the receiving service and returns a /// wrapped version of it. fn map_err<F, E>(self, f: F) -> MapErr<Self, F, E> where Self: Sized, F: Fn(Self::Error) -> E, { MapErr::new(self, f) } } impl<T: ?Sized> ServiceExt for T where T: Service {} /// Creates new `Service` values. /// /// Acts as a service factory. This is useful for cases where new `Service` /// values must be produced. One case is a TCP servier listener. The listner /// accepts new TCP streams, obtains a new `Service` value using the /// `NewService` trait, and uses that new `Service` value to process inbound /// requests on that new TCP stream. /// /// `Config` is a service factory configuration type. pub trait NewService<Config = ()> { /// Requests handled by the service. type Request; /// Responses given by the service type Response; /// Errors produced by the service type Error; /// The `Service` value created by this factory type Service: Service< Request = Self::Request, Response = Self::Response, Error = Self::Error, >; /// Errors produced while building a service. type InitError; /// The future of the `Service` instance. type Future: IntoFuture<Item = Self::Service, Error = Self::InitError>; /// Create and return a new service value asynchronously. fn new_service(&self, cfg: &Config) -> Self::Future; /// Apply function to specified service and use it as a next service in /// chain. fn apply<T, T1, B, B1>( self, transform: T1, service: B1, ) -> AndThenTransform<T, Self, B, Config> where Self: Sized, T: Transform<B::Service, Request = Self::Response, InitError = Self::InitError>, T::Error: From<Self::Error>, T1: IntoTransform<T, B::Service>, B: NewService<Config, InitError = Self::InitError>, B1: IntoNewService<B, Config>, { AndThenTransform::new(transform.into_transform(), self, service.into_new_service()) } /// Apply function to specified service and use it as a next service in /// chain. fn apply_fn<B, I, F, Out>( self, service: I, f: F, ) -> AndThenApplyNewService<Self, B, F, Out, Config> where Self: Sized, B: NewService<Config, Error = Self::Error, InitError = Self::InitError>, I: IntoNewService<B, Config>, F: FnMut(Self::Response, &mut B::Service) -> Out, Out: IntoFuture, Out::Error: Into<Self::Error>, { AndThenApplyNewService::new(self, service, f) } /// Call another service after call to this one has resolved successfully. fn and_then<F, B>(self, new_service: F) -> AndThenNewService<Self, B, Config> where Self: Sized, F: IntoNewService<B, Config>, B: NewService< Config, Request = Self::Response, Error = Self::Error, InitError = Self::InitError, >, { AndThenNewService::new(self, new_service) } /// `NewService` that create service to map this service's error /// and new service's init error to any error /// implementing `From` for this service`s `Error`. /// /// Note that this function consumes the receiving new service and returns a /// wrapped version of it. fn from_err<E>(self) -> FromErrNewService<Self, E, Config> where Self: Sized, E: From<Self::Error>, { FromErrNewService::new(self) } /// Create `NewService` to chain on a computation for when a call to the /// service finished, passing the result of the call to the next /// service `B`. /// /// Note that this function consumes the receiving future and returns a /// wrapped version of it. fn then<F, B>(self, new_service: F) -> ThenNewService<Self, B, Config> where Self: Sized, F: IntoNewService<B, Config>, B: NewService< Config, Request = Result<Self::Response, Self::Error>, Error = Self::Error, InitError = Self::InitError, >, { ThenNewService::new(self, new_service) } /// Map this service's output to a different type, returning a new service /// of the resulting type. fn map<F, R>(self, f: F) -> MapNewService<Self, F, R, Config> where Self: Sized, F: FnMut(Self::Response) -> R, { MapNewService::new(self, f) } /// Map this service's error to a different error, returning a new service. fn map_err<F, E>(self, f: F) -> MapErrNewService<Self, F, E, Config> where Self: Sized, F: Fn(Self::Error) -> E, { MapErrNewService::new(self, f) } /// Map this service's init error to a different error, returning a new service. fn map_init_err<F, E>(self, f: F) -> MapInitErr<Self, F, E, Config> where Self: Sized, F: Fn(Self::InitError) -> E, { MapInitErr::new(self, f) } } impl<'a, S> Service for &'a mut S where S: Service + 'a, { type Request = S::Request; type Response = S::Response; type Error = S::Error; type Future = S::Future; fn poll_ready(&mut self) -> Poll<(), S::Error> { (**self).poll_ready() } fn call(&mut self, request: Self::Request) -> S::Future { (**self).call(request) } } impl<S> Service for Box<S> where S: Service + ?Sized, { type Request = S::Request; type Response = S::Response; type Error = S::Error; type Future = S::Future; fn poll_ready(&mut self) -> Poll<(), S::Error> { (**self).poll_ready() } fn call(&mut self, request: Self::Request) -> S::Future { (**self).call(request) } } impl<S, C> NewService<C> for Rc<S> where S: NewService<C>, { type Request = S::Request; type Response = S::Response; type Error = S::Error; type Service = S::Service; type InitError = S::InitError; type Future = S::Future; fn new_service(&self, cfg: &C) -> S::Future { self.as_ref().new_service(cfg) } } impl<S, C> NewService<C> for Arc<S> where S: NewService<C>, { type Request = S::Request; type Response = S::Response; type Error = S::Error; type Service = S::Service; type InitError = S::InitError; type Future = S::Future; fn new_service(&self, cfg: &C) -> S::Future { self.as_ref().new_service(cfg) } } /// Trait for types that can be converted to a `Service` pub trait IntoService<T> where T: Service, { /// Convert to a `Service` fn into_service(self) -> T; } /// Trait for types that can be converted to a `NewService` pub trait IntoNewService<T, C = ()> where T: NewService<C>, { /// Convert to an `NewService` fn into_new_service(self) -> T; } impl<T> IntoService<T> for T where T: Service, { fn into_service(self) -> T { self } } impl<T, C> IntoNewService<T, C> for T where T: NewService<C>, { fn into_new_service(self) -> T { self } } /// Trait for types that can be converted to a configurable `NewService` pub trait IntoConfigurableNewService<T, C> where T: NewService<C>, { /// Convert to an `NewService` fn into_new_service(self) -> T; } impl<T, C> IntoConfigurableNewService<T, C> for T where T: NewService<C>, { fn into_new_service(self) -> T { self } }