This commit is contained in:
nora 2022-09-15 21:35:25 +02:00
parent b1cba78afa
commit f5f20836d4
4 changed files with 90 additions and 308 deletions

90
tower/tower/src/make.rs Normal file
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//! Trait aliases for Services that produce specific types of Responses.
pub use self::make_service::shared::Shared;
pub use self::make_service::MakeService;
pub mod future {
//! Future types
pub use super::make_service::shared::SharedFuture;
}
mod make_service {
//! Contains [`MakeService`] which is a trait alias for a [`Service`] of [`Service`]s.
use crate::sealed::Sealed;
use std::fmt;
use std::future::Future;
use std::marker::PhantomData;
use std::task::{Context, Poll};
use tower_service::Service;
pub mod shared {
use std::convert::Infallible;
use std::task::{Context, Poll};
use tower_service::Service;
pub struct Shared<S> {
service: S,
}
impl<S, T> Service<T> for Shared<S>
where
S: Clone,
{
type Response = S;
type Error = Infallible;
type Future = SharedFuture<S>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
todo!()
}
fn call(&mut self, _target: T) -> Self::Future {
todo!()
}
}
opaque_future! {
/// Response future from [`Shared`] services.
pub type SharedFuture<S> = futures_util::future::Ready<Result<S, Infallible>>;
}
}
pub trait MakeService<Target, Request> {
type Response;
type Error;
type Service: Service<Request, Response = Self::Response, Error = Self::Error>;
type MakeError;
type Future;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::MakeError>>;
fn make_service(&mut self, target: Target) -> Self::Future;
}
impl<M, S, Target, Request> Sealed<(Target, Request)> for M
where
M: Service<Target, Response = S>,
S: Service<Request>,
{
}
impl<M, S, Target, Request> MakeService<Target, Request> for M
where
M: Service<Target, Response = S>,
S: Service<Request>,
{
type Response = S::Response;
type Error = S::Error;
type Service = S;
type MakeError = M::Error;
type Future = M::Future;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::MakeError>> {
Service::poll_ready(self, cx)
}
fn make_service(&mut self, target: Target) -> Self::Future {
Service::call(self, target)
}
}
}

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//! Contains [`MakeService`] which is a trait alias for a [`Service`] of [`Service`]s.
use crate::sealed::Sealed;
use std::fmt;
use std::future::Future;
use std::marker::PhantomData;
use std::task::{Context, Poll};
use tower_service::Service;
pub(crate) mod shared;
/// 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 server listener. The listener
/// accepts new TCP streams, obtains a new [`Service`] value using the
/// [`MakeService`] trait, and uses that new [`Service`] value to process inbound
/// requests on that new TCP stream.
///
/// This is essentially a trait alias for a [`Service`] of [`Service`]s.
pub trait MakeService<Target, Request> {
type Response;
type Error;
type Service: Service<Request, Response = Self::Response, Error = Self::Error>;
type MakeError;
type Future;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::MakeError>>;
fn make_service(&mut self, target: Target) -> Self::Future;
}
impl<M, S, Target, Request> Sealed<(Target, Request)> for M
where
M: Service<Target, Response = S>,
S: Service<Request>,
{
}
impl<M, S, Target, Request> MakeService<Target, Request> for M
where
M: Service<Target, Response = S>,
S: Service<Request>,
{
type Response = S::Response;
type Error = S::Error;
type Service = S;
type MakeError = M::Error;
type Future = M::Future;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::MakeError>> {
Service::poll_ready(self, cx)
}
fn make_service(&mut self, target: Target) -> Self::Future {
Service::call(self, target)
}
}
/// Service returned by [`MakeService::into_service`][into].
///
/// See the documentation on [`into_service`][into] for details.
///
/// [into]: MakeService::into_service
pub struct IntoService<M, Request> {
make: M,
_marker: PhantomData<Request>,
}
impl<M, Request> Clone for IntoService<M, Request>
where
M: Clone,
{
fn clone(&self) -> Self {
Self {
make: self.make.clone(),
_marker: PhantomData,
}
}
}
impl<M, Request> fmt::Debug for IntoService<M, Request>
where
M: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("IntoService")
.field("make", &self.make)
.finish()
}
}
impl<M, S, Target, Request> Service<Target> for IntoService<M, Request>
where
M: Service<Target, Response = S>,
S: Service<Request>,
{
type Response = M::Response;
type Error = M::Error;
type Future = M::Future;
#[inline]
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.make.poll_ready(cx)
}
#[inline]
fn call(&mut self, target: Target) -> Self::Future {
self.make.make_service(target)
}
}
/// Service returned by [`MakeService::as_service`][as].
///
/// See the documentation on [`as_service`][as] for details.
///
/// [as]: MakeService::as_service
pub struct AsService<'a, M, Request> {
make: &'a mut M,
_marker: PhantomData<Request>,
}
impl<M, Request> fmt::Debug for AsService<'_, M, Request>
where
M: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("AsService")
.field("make", &self.make)
.finish()
}
}
impl<M, S, Target, Request> Service<Target> for AsService<'_, M, Request>
where
M: Service<Target, Response = S>,
S: Service<Request>,
{
type Response = M::Response;
type Error = M::Error;
type Future = M::Future;
#[inline]
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.make.poll_ready(cx)
}
#[inline]
fn call(&mut self, target: Target) -> Self::Future {
self.make.make_service(target)
}
}

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use std::convert::Infallible;
use std::task::{Context, Poll};
use tower_service::Service;
/// A [`MakeService`] that produces services by cloning an inner service.
///
/// [`MakeService`]: super::MakeService
///
/// # Example
///
/// ```
/// # use std::task::{Context, Poll};
/// # use std::pin::Pin;
/// # use std::convert::Infallible;
/// use tower::make::{MakeService, Shared};
/// use tower::buffer::Buffer;
/// use tower::Service;
/// use futures::future::{Ready, ready};
///
/// // An example connection type
/// struct Connection {}
///
/// // An example request type
/// struct Request {}
///
/// // An example response type
/// struct Response {}
///
/// // Some service that doesn't implement `Clone`
/// struct MyService;
///
/// impl Service<Request> for MyService {
/// type Response = Response;
/// type Error = Infallible;
/// type Future = Ready<Result<Response, Infallible>>;
///
/// fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
/// Poll::Ready(Ok(()))
/// }
///
/// fn call(&mut self, req: Request) -> Self::Future {
/// ready(Ok(Response {}))
/// }
/// }
///
/// // Example function that runs a service by accepting new connections and using
/// // `Make` to create new services that might be bound to the connection.
/// //
/// // This is similar to what you might find in hyper.
/// async fn serve_make_service<Make>(make: Make)
/// where
/// Make: MakeService<Connection, Request>
/// {
/// // ...
/// }
///
/// # async {
/// // Our service
/// let svc = MyService;
///
/// // Make it `Clone` by putting a channel in front
/// let buffered = Buffer::new(svc, 1024);
///
/// // Convert it into a `MakeService`
/// let make = Shared::new(buffered);
///
/// // Run the service and just ignore the `Connection`s as `MyService` doesn't need them
/// serve_make_service(make).await;
/// # };
/// ```
#[derive(Debug, Clone, Copy)]
pub struct Shared<S> {
service: S,
}
impl<S> Shared<S> {
/// Create a new [`Shared`] from a service.
pub fn new(service: S) -> Self {
Self { service }
}
}
impl<S, T> Service<T> for Shared<S>
where
S: Clone,
{
type Response = S;
type Error = Infallible;
type Future = SharedFuture<S>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Ready(Ok(()))
}
fn call(&mut self, _target: T) -> Self::Future {
SharedFuture::new(futures_util::future::ready(Ok(self.service.clone())))
}
}
opaque_future! {
/// Response future from [`Shared`] services.
pub type SharedFuture<S> = futures_util::future::Ready<Result<S, Infallible>>;
}
#[cfg(test)]
mod tests {
use super::*;
use crate::make::MakeService;
use crate::service_fn;
use futures::future::poll_fn;
async fn echo<R>(req: R) -> Result<R, Infallible> {
Ok(req)
}
#[tokio::test]
async fn as_make_service() {
let mut shared = Shared::new(service_fn(echo::<&'static str>));
poll_fn(|cx| MakeService::<(), _>::poll_ready(&mut shared, cx))
.await
.unwrap();
let mut svc = shared.make_service(()).await.unwrap();
poll_fn(|cx| svc.poll_ready(cx)).await.unwrap();
let res = svc.call("foo").await.unwrap();
assert_eq!(res, "foo");
}
#[tokio::test]
async fn as_make_service_into_service() {
let shared = Shared::new(service_fn(echo::<&'static str>));
let mut shared = MakeService::<(), _>::into_service(shared);
poll_fn(|cx| Service::<()>::poll_ready(&mut shared, cx))
.await
.unwrap();
let mut svc = shared.call(()).await.unwrap();
poll_fn(|cx| svc.poll_ready(cx)).await.unwrap();
let res = svc.call("foo").await.unwrap();
assert_eq!(res, "foo");
}
}

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//! Trait aliases for Services that produce specific types of Responses.
mod make_service;
pub use self::make_service::shared::Shared;
pub use self::make_service::{AsService, IntoService, MakeService};
pub mod future {
//! Future types
pub use super::make_service::shared::SharedFuture;
}