use std::cell::RefCell;
use std::future::Future;
use std::marker::PhantomData;
use std::pin::Pin;
use std::rc::Rc;
use std::task::{Context, Poll};
use crate::{Service, ServiceFactory};
pub fn apply_cfg<F, C, T, R, S, E>(
srv: T,
f: F,
) -> impl ServiceFactory<
Config = C,
Request = S::Request,
Response = S::Response,
Error = S::Error,
Service = S,
InitError = E,
Future = R,
> + Clone
where
F: FnMut(C, &mut T) -> R,
T: Service,
R: Future<Output = Result<S, E>>,
S: Service,
{
ApplyConfigService {
srv: Rc::new(RefCell::new((srv, f))),
_t: PhantomData,
}
}
pub fn apply_cfg_factory<F, C, T, R, S>(
factory: T,
f: F,
) -> impl ServiceFactory<
Config = C,
Request = S::Request,
Response = S::Response,
Error = S::Error,
Service = S,
InitError = T::InitError,
> + Clone
where
F: FnMut(C, &mut T::Service) -> R,
T: ServiceFactory<Config = ()>,
T::InitError: From<T::Error>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
ApplyConfigServiceFactory {
srv: Rc::new(RefCell::new((factory, f))),
_t: PhantomData,
}
}
struct ApplyConfigService<F, C, T, R, S, E>
where
F: FnMut(C, &mut T) -> R,
T: Service,
R: Future<Output = Result<S, E>>,
S: Service,
{
srv: Rc<RefCell<(T, F)>>,
_t: PhantomData<(C, R, S)>,
}
impl<F, C, T, R, S, E> Clone for ApplyConfigService<F, C, T, R, S, E>
where
F: FnMut(C, &mut T) -> R,
T: Service,
R: Future<Output = Result<S, E>>,
S: Service,
{
fn clone(&self) -> Self {
ApplyConfigService {
srv: self.srv.clone(),
_t: PhantomData,
}
}
}
impl<F, C, T, R, S, E> ServiceFactory for ApplyConfigService<F, C, T, R, S, E>
where
F: FnMut(C, &mut T) -> R,
T: Service,
R: Future<Output = Result<S, E>>,
S: Service,
{
type Config = C;
type Request = S::Request;
type Response = S::Response;
type Error = S::Error;
type Service = S;
type InitError = E;
type Future = R;
fn new_service(&self, cfg: C) -> Self::Future {
let (t, f) = &mut *self.srv.borrow_mut();
f(cfg, t)
}
}
struct ApplyConfigServiceFactory<F, C, T, R, S>
where
F: FnMut(C, &mut T::Service) -> R,
T: ServiceFactory<Config = ()>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
srv: Rc<RefCell<(T, F)>>,
_t: PhantomData<(C, R, S)>,
}
impl<F, C, T, R, S> Clone for ApplyConfigServiceFactory<F, C, T, R, S>
where
F: FnMut(C, &mut T::Service) -> R,
T: ServiceFactory<Config = ()>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
fn clone(&self) -> Self {
Self {
srv: self.srv.clone(),
_t: PhantomData,
}
}
}
impl<F, C, T, R, S> ServiceFactory for ApplyConfigServiceFactory<F, C, T, R, S>
where
F: FnMut(C, &mut T::Service) -> R,
T: ServiceFactory<Config = ()>,
T::InitError: From<T::Error>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
type Config = C;
type Request = S::Request;
type Response = S::Response;
type Error = S::Error;
type Service = S;
type InitError = T::InitError;
type Future = ApplyConfigServiceFactoryResponse<F, C, T, R, S>;
fn new_service(&self, cfg: C) -> Self::Future {
ApplyConfigServiceFactoryResponse {
cfg: Some(cfg),
store: self.srv.clone(),
state: State::A(self.srv.borrow().0.new_service(())),
}
}
}
#[pin_project::pin_project]
struct ApplyConfigServiceFactoryResponse<F, C, T, R, S>
where
F: FnMut(C, &mut T::Service) -> R,
T: ServiceFactory<Config = ()>,
T::InitError: From<T::Error>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
cfg: Option<C>,
store: Rc<RefCell<(T, F)>>,
#[pin]
state: State<T, R, S>,
}
#[pin_project::pin_project(project = StateProj)]
enum State<T, R, S>
where
T: ServiceFactory<Config = ()>,
T::InitError: From<T::Error>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
A(#[pin] T::Future),
B(T::Service),
C(#[pin] R),
}
impl<F, C, T, R, S> Future for ApplyConfigServiceFactoryResponse<F, C, T, R, S>
where
F: FnMut(C, &mut T::Service) -> R,
T: ServiceFactory<Config = ()>,
T::InitError: From<T::Error>,
R: Future<Output = Result<S, T::InitError>>,
S: Service,
{
type Output = Result<S, T::InitError>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let mut this = self.as_mut().project();
match this.state.as_mut().project() {
StateProj::A(fut) => match fut.poll(cx)? {
Poll::Pending => Poll::Pending,
Poll::Ready(srv) => {
this.state.set(State::B(srv));
self.poll(cx)
}
},
StateProj::B(srv) => match srv.poll_ready(cx)? {
Poll::Ready(_) => {
{
let (_, f) = &mut *this.store.borrow_mut();
let fut = f(this.cfg.take().unwrap(), srv);
this.state.set(State::C(fut));
}
self.poll(cx)
}
Poll::Pending => Poll::Pending,
},
StateProj::C(fut) => fut.poll(cx),
}
}
}