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use crate::SendOperationError;
use aws_smithy_http::middleware::{AsyncMapRequest, MapRequest};
use aws_smithy_http::operation;
use pin_project::pin_project;
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use tower::{Layer, Service};
#[derive(Debug)]
pub struct AsyncMapRequestLayer<M> {
mapper: M,
}
impl<M: AsyncMapRequest + Clone> AsyncMapRequestLayer<M> {
pub fn for_mapper(mapper: M) -> Self {
AsyncMapRequestLayer { mapper }
}
}
impl<S, M> Layer<S> for AsyncMapRequestLayer<M>
where
M: Clone,
{
type Service = AsyncMapRequestService<S, M>;
fn layer(&self, inner: S) -> Self::Service {
AsyncMapRequestService {
inner,
mapper: self.mapper.clone(),
}
}
}
#[derive(Clone)]
pub struct AsyncMapRequestService<S, M> {
inner: S,
mapper: M,
}
type BoxFuture<T> = Pin<Box<dyn Future<Output = T> + Send>>;
impl<S, M> Service<operation::Request> for AsyncMapRequestService<S, M>
where
S: Service<operation::Request, Error = SendOperationError> + Clone + Send + 'static,
M: AsyncMapRequest,
S::Future: Send + 'static,
{
type Response = S::Response;
type Error = S::Error;
type Future = BoxFuture<Result<S::Response, S::Error>>;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.inner.poll_ready(cx)
}
fn call(&mut self, req: operation::Request) -> Self::Future {
let mut inner = self.inner.clone();
let future = self.mapper.apply(req);
Box::pin(async move {
let mapped_request = future
.await
.map_err(|e| SendOperationError::RequestConstructionError(e.into()))?;
inner.call(mapped_request).await
})
}
}
#[derive(Debug, Default)]
pub struct MapRequestLayer<M> {
mapper: M,
}
impl<M: MapRequest + Clone> MapRequestLayer<M> {
pub fn for_mapper(mapper: M) -> Self {
MapRequestLayer { mapper }
}
}
impl<S, M> Layer<S> for MapRequestLayer<M>
where
M: Clone,
{
type Service = MapRequestService<S, M>;
fn layer(&self, inner: S) -> Self::Service {
MapRequestService {
inner,
mapper: self.mapper.clone(),
}
}
}
#[pin_project(project = EnumProj)]
pub enum MapRequestFuture<F, E> {
Inner(#[pin] F),
Ready(Option<E>),
}
impl<O, F, E> Future for MapRequestFuture<F, E>
where
F: Future<Output = Result<O, E>>,
{
type Output = Result<O, E>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
match self.project() {
EnumProj::Ready(e) => Poll::Ready(Err(e.take().unwrap())),
EnumProj::Inner(f) => f.poll(cx),
}
}
}
#[derive(Clone)]
pub struct MapRequestService<S, M> {
inner: S,
mapper: M,
}
impl<S, M> Service<operation::Request> for MapRequestService<S, M>
where
S: Service<operation::Request, Error = SendOperationError>,
M: MapRequest,
{
type Response = S::Response;
type Error = S::Error;
type Future = MapRequestFuture<S::Future, S::Error>;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.inner.poll_ready(cx)
}
fn call(&mut self, req: operation::Request) -> Self::Future {
match self
.mapper
.apply(req)
.map_err(|e| SendOperationError::RequestConstructionError(e.into()))
{
Err(e) => MapRequestFuture::Ready(Some(e)),
Ok(req) => MapRequestFuture::Inner(self.inner.call(req)),
}
}
}
