From 87bca22cc71717ff3514b996a12e530c6b2cc14c Mon Sep 17 00:00:00 2001
From: Rob Ede <robjtede@icloud.com>
Date: Sun, 27 Dec 2020 03:55:33 +0000
Subject: [PATCH] migrate over to pin-project-lite

---
 actix-service/Cargo.toml               |   5 +-
 actix-service/src/and_then.rs          |  82 +++---
 actix-service/src/and_then_apply_fn.rs | 334 -------------------------
 actix-service/src/apply.rs             |  27 +-
 actix-service/src/apply_cfg.rs         |  71 +++---
 actix-service/src/lib.rs               |   1 -
 actix-service/src/map.rs               |  40 +--
 actix-service/src/map_err.rs           |  40 +--
 actix-service/src/map_init_err.rs      |  21 +-
 actix-service/src/pipeline.rs          |  57 -----
 actix-service/src/then.rs              |  85 ++++---
 actix-service/src/transform.rs         |  49 ++--
 actix-service/src/transform_err.rs     |  17 +-
 13 files changed, 247 insertions(+), 582 deletions(-)
 delete mode 100644 actix-service/src/and_then_apply_fn.rs

diff --git a/actix-service/Cargo.toml b/actix-service/Cargo.toml
index df3087ef..60818968 100644
--- a/actix-service/Cargo.toml
+++ b/actix-service/Cargo.toml
@@ -17,8 +17,9 @@ name = "actix_service"
 path = "src/lib.rs"
 
 [dependencies]
-futures-util = "0.3.1"
-pin-project = "1.0.0"
+pin-project-lite = "0.2"
+futures-util = { version = "0.3.7", default-features = false }
+futures-core = { version = "0.3.7", default-features = false }
 
 [dev-dependencies]
 actix-rt = "1.0.0"
diff --git a/actix-service/src/and_then.rs b/actix-service/src/and_then.rs
index 863c8dd1..17d62e8f 100644
--- a/actix-service/src/and_then.rs
+++ b/actix-service/src/and_then.rs
@@ -7,6 +7,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use super::{Service, ServiceFactory};
 
 /// Service for the `and_then` combinator, chaining a computation onto the end
@@ -53,30 +55,43 @@ where
 
     fn call(&mut self, req: Req) -> Self::Future {
         AndThenServiceResponse {
-            state: State::A(self.0.borrow_mut().0.call(req), Some(self.0.clone())),
+            state: State::A {
+                fut: self.0.borrow_mut().0.call(req),
+                b: Some(self.0.clone()),
+            },
         }
     }
 }
 
-#[pin_project::pin_project]
-pub(crate) struct AndThenServiceResponse<A, B, Req>
-where
-    A: Service<Req>,
-    B: Service<A::Response, Error = A::Error>,
-{
-    #[pin]
-    state: State<A, B, Req>,
+pin_project! {
+    pub(crate) struct AndThenServiceResponse<A, B, Req>
+    where
+        A: Service<Req>,
+        B: Service<A::Response, Error = A::Error>,
+    {
+        #[pin]
+        state: State<A, B, Req>,
+    }
 }
 
-#[pin_project::pin_project(project = StateProj)]
-enum State<A, B, Req>
-where
-    A: Service<Req>,
-    B: Service<A::Response, Error = A::Error>,
-{
-    A(#[pin] A::Future, Option<Rc<RefCell<(A, B)>>>),
-    B(#[pin] B::Future),
-    Empty,
+pin_project! {
+    #[project = StateProj]
+    enum State<A, B, Req>
+    where
+        A: Service<Req>,
+        B: Service<A::Response, Error = A::Error>,
+    {
+        A {
+            #[pin]
+            fut: A::Future,
+            b: Option<Rc<RefCell<(A, B)>>>,
+        },
+        B {
+            #[pin]
+            fut: B::Future,
+        },
+        Empty,
+    }
 }
 
 impl<A, B, Req> Future for AndThenServiceResponse<A, B, Req>
@@ -90,17 +105,17 @@ where
         let mut this = self.as_mut().project();
 
         match this.state.as_mut().project() {
-            StateProj::A(fut, b) => match fut.poll(cx)? {
+            StateProj::A { fut, b } => match fut.poll(cx)? {
                 Poll::Ready(res) => {
                     let b = b.take().unwrap();
                     this.state.set(State::Empty); // drop fut A
                     let fut = b.borrow_mut().1.call(res);
-                    this.state.set(State::B(fut));
+                    this.state.set(State::B { fut });
                     self.poll(cx)
                 }
                 Poll::Pending => Poll::Pending,
             },
-            StateProj::B(fut) => fut.poll(cx).map(|r| {
+            StateProj::B { fut } => fut.poll(cx).map(|r| {
                 this.state.set(State::Empty);
                 r
             }),
@@ -194,19 +209,20 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub(crate) struct AndThenServiceFactoryResponse<A, B, Req>
-where
-    A: ServiceFactory<Req>,
-    B: ServiceFactory<A::Response>,
-{
-    #[pin]
-    fut_a: A::Future,
-    #[pin]
-    fut_b: B::Future,
+pin_project! {
+    pub(crate) struct AndThenServiceFactoryResponse<A, B, Req>
+    where
+        A: ServiceFactory<Req>,
+        B: ServiceFactory<A::Response>,
+    {
+        #[pin]
+        fut_a: A::Future,
+        #[pin]
+        fut_b: B::Future,
 
-    a: Option<A::Service>,
-    b: Option<B::Service>,
+        a: Option<A::Service>,
+        b: Option<B::Service>,
+    }
 }
 
 impl<A, B, Req> AndThenServiceFactoryResponse<A, B, Req>
diff --git a/actix-service/src/and_then_apply_fn.rs b/actix-service/src/and_then_apply_fn.rs
deleted file mode 100644
index 5638bc8c..00000000
--- a/actix-service/src/and_then_apply_fn.rs
+++ /dev/null
@@ -1,334 +0,0 @@
-use alloc::rc::Rc;
-use core::{
-    cell::RefCell,
-    future::Future,
-    marker::PhantomData,
-    pin::Pin,
-    task::{Context, Poll},
-};
-
-use crate::{Service, ServiceFactory};
-
-/// `Apply` service combinator
-pub(crate) struct AndThenApplyFn<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    svc: Rc<RefCell<(S1, S2, F)>>,
-    _phantom: PhantomData<(Fut, Req, In, Res, Err)>,
-}
-
-impl<S1, S2, F, Fut, Req, In, Res, Err> AndThenApplyFn<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    /// Create new `Apply` combinator
-    pub(crate) fn new(a: S1, b: S2, wrap_fn: F) -> Self {
-        Self {
-            svc: Rc::new(RefCell::new((a, b, wrap_fn))),
-            _phantom: PhantomData,
-        }
-    }
-}
-
-impl<S1, S2, F, Fut, Req, In, Res, Err> Clone
-    for AndThenApplyFn<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    fn clone(&self) -> Self {
-        AndThenApplyFn {
-            svc: self.svc.clone(),
-            _phantom: PhantomData,
-        }
-    }
-}
-
-impl<S1, S2, F, Fut, Req, In, Res, Err> Service<Req>
-    for AndThenApplyFn<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    type Response = Res;
-    type Error = Err;
-    type Future = AndThenApplyFnFuture<S1, S2, F, Fut, Req, In, Res, Err>;
-
-    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        let mut inner = self.svc.borrow_mut();
-        let not_ready = inner.0.poll_ready(cx)?.is_pending();
-        if inner.1.poll_ready(cx)?.is_pending() || not_ready {
-            Poll::Pending
-        } else {
-            Poll::Ready(Ok(()))
-        }
-    }
-
-    fn call(&mut self, req: Req) -> Self::Future {
-        let fut = self.svc.borrow_mut().0.call(req);
-        AndThenApplyFnFuture {
-            state: State::A(fut, Some(self.svc.clone())),
-        }
-    }
-}
-
-#[pin_project::pin_project]
-pub(crate) struct AndThenApplyFnFuture<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    #[pin]
-    state: State<S1, S2, F, Fut, Req, In, Res, Err>,
-}
-
-#[pin_project::pin_project(project = StateProj)]
-enum State<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    A(#[pin] S1::Future, Option<Rc<RefCell<(S1, S2, F)>>>),
-    B(#[pin] Fut),
-    Empty(PhantomData<In>),
-}
-
-impl<S1, S2, F, Fut, Req, In, Res, Err> Future
-    for AndThenApplyFnFuture<S1, S2, F, Fut, Req, In, Res, Err>
-where
-    S1: Service<Req>,
-    S2: Service<In>,
-    F: FnMut(S1::Response, &mut S2) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<S1::Error> + From<S2::Error>,
-{
-    type Output = Result<Res, Err>;
-
-    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, b) => match fut.poll(cx)? {
-                Poll::Ready(res) => {
-                    let b = Option::take(b).unwrap();
-                    this.state.set(State::Empty(PhantomData));
-                    let (_, b, f) = &mut *b.borrow_mut();
-                    let fut = f(res, b);
-                    this.state.set(State::B(fut));
-                    self.poll(cx)
-                }
-                Poll::Pending => Poll::Pending,
-            },
-            StateProj::B(fut) => fut.poll(cx).map(|r| {
-                this.state.set(State::Empty(PhantomData));
-                r
-            }),
-            StateProj::Empty(_) => {
-                panic!("future must not be polled after it returned `Poll::Ready`")
-            }
-        }
-    }
-}
-
-/// `AndThenApplyFn` service factory
-pub(crate) struct AndThenApplyFnFactory<SF1, SF2, F, Fut, Req, In, Res, Err> {
-    srv: Rc<(SF1, SF2, F)>,
-    _phantom: PhantomData<(Fut, Req, In, Res, Err)>,
-}
-
-impl<SF1, SF2, F, Fut, Req, In, Res, Err>
-    AndThenApplyFnFactory<SF1, SF2, F, Fut, Req, In, Res, Err>
-where
-    SF1: ServiceFactory<Req>,
-    SF2: ServiceFactory<In, Config = SF1::Config, InitError = SF1::InitError>,
-    F: FnMut(SF1::Response, &mut SF2::Service) -> Fut + Clone,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<SF1::Error> + From<SF2::Error>,
-{
-    /// Create new `ApplyNewService` new service instance
-    pub(crate) fn new(a: SF1, b: SF2, wrap_fn: F) -> Self {
-        Self {
-            srv: Rc::new((a, b, wrap_fn)),
-            _phantom: PhantomData,
-        }
-    }
-}
-
-impl<SF1, SF2, F, Fut, Req, In, Res, Err> Clone
-    for AndThenApplyFnFactory<SF1, SF2, F, Fut, Req, In, Res, Err>
-{
-    fn clone(&self) -> Self {
-        Self {
-            srv: self.srv.clone(),
-            _phantom: PhantomData,
-        }
-    }
-}
-
-impl<SF1, SF2, F, Fut, Req, In, Res, Err> ServiceFactory<Req>
-    for AndThenApplyFnFactory<SF1, SF2, F, Fut, Req, In, Res, Err>
-where
-    SF1: ServiceFactory<Req>,
-    SF1::Config: Clone,
-    SF2: ServiceFactory<In, Config = SF1::Config, InitError = SF1::InitError>,
-    F: FnMut(SF1::Response, &mut SF2::Service) -> Fut + Clone,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<SF1::Error> + From<SF2::Error>,
-{
-    type Response = Res;
-    type Error = Err;
-    type Service = AndThenApplyFn<SF1::Service, SF2::Service, F, Fut, Req, In, Res, Err>;
-    type Config = SF1::Config;
-    type InitError = SF1::InitError;
-    type Future = AndThenApplyFnFactoryResponse<SF1, SF2, F, Fut, Req, In, Res, Err>;
-
-    fn new_service(&self, cfg: SF1::Config) -> Self::Future {
-        let srv = &*self.srv;
-        AndThenApplyFnFactoryResponse {
-            s1: None,
-            s2: None,
-            wrap_fn: srv.2.clone(),
-            fut_s1: srv.0.new_service(cfg.clone()),
-            fut_s2: srv.1.new_service(cfg),
-            _phantom: PhantomData,
-        }
-    }
-}
-
-#[pin_project::pin_project]
-pub(crate) struct AndThenApplyFnFactoryResponse<SF1, SF2, F, Fut, Req, In, Res, Err>
-where
-    SF1: ServiceFactory<Req>,
-    SF2: ServiceFactory<In, Config = SF1::Config, InitError = SF1::InitError>,
-    F: FnMut(SF1::Response, &mut SF2::Service) -> Fut + Clone,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<SF1::Error>,
-    Err: From<SF2::Error>,
-{
-    #[pin]
-    fut_s1: SF1::Future,
-    #[pin]
-    fut_s2: SF2::Future,
-    wrap_fn: F,
-    s1: Option<SF1::Service>,
-    s2: Option<SF2::Service>,
-    _phantom: PhantomData<In>,
-}
-
-impl<SF1, SF2, F, Fut, Req, In, Res, Err> Future
-    for AndThenApplyFnFactoryResponse<SF1, SF2, F, Fut, Req, In, Res, Err>
-where
-    SF1: ServiceFactory<Req>,
-    SF2: ServiceFactory<In, Config = SF1::Config, InitError = SF1::InitError>,
-    F: FnMut(SF1::Response, &mut SF2::Service) -> Fut + Clone,
-    Fut: Future<Output = Result<Res, Err>>,
-    Err: From<SF1::Error> + From<SF2::Error>,
-{
-    type Output = Result<
-        AndThenApplyFn<SF1::Service, SF2::Service, F, Fut, Req, In, Res, Err>,
-        SF1::InitError,
-    >;
-
-    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        let this = self.project();
-
-        if this.s1.is_none() {
-            if let Poll::Ready(service) = this.fut_s1.poll(cx)? {
-                *this.s1 = Some(service);
-            }
-        }
-
-        if this.s2.is_none() {
-            if let Poll::Ready(service) = this.fut_s2.poll(cx)? {
-                *this.s2 = Some(service);
-            }
-        }
-
-        if this.s1.is_some() && this.s2.is_some() {
-            Poll::Ready(Ok(AndThenApplyFn {
-                svc: Rc::new(RefCell::new((
-                    Option::take(this.s1).unwrap(),
-                    Option::take(this.s2).unwrap(),
-                    this.wrap_fn.clone(),
-                ))),
-                _phantom: PhantomData,
-            }))
-        } else {
-            Poll::Pending
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    use futures_util::future::{lazy, ok, Ready, TryFutureExt};
-
-    use crate::{fn_service, pipeline, pipeline_factory, Service, ServiceFactory};
-
-    #[derive(Clone)]
-    struct Srv;
-
-    impl Service<u8> for Srv {
-        type Response = ();
-        type Error = ();
-        type Future = Ready<Result<Self::Response, Self::Error>>;
-
-        crate::always_ready!();
-
-        fn call(&mut self, req: u8) -> Self::Future {
-            let _ = req;
-            ok(())
-        }
-    }
-
-    #[actix_rt::test]
-    async fn test_service() {
-        let mut srv = pipeline(ok).and_then_apply_fn(Srv, |req: &'static str, s| {
-            s.call(1).map_ok(move |res| (req, res))
-        });
-        let res = lazy(|cx| srv.poll_ready(cx)).await;
-        assert!(res.is_ready());
-
-        let res = srv.call("srv").await;
-        assert!(res.is_ok());
-        assert_eq!(res.unwrap(), ("srv", ()));
-    }
-
-    #[actix_rt::test]
-    async fn test_service_factory() {
-        let new_srv = pipeline_factory(|| ok::<_, ()>(fn_service(ok))).and_then_apply_fn(
-            || ok(Srv),
-            |req: &'static str, s| s.call(1).map_ok(move |res| (req, res)),
-        );
-        let mut srv = new_srv.new_service(()).await.unwrap();
-        let res = lazy(|cx| srv.poll_ready(cx)).await;
-        assert!(res.is_ready());
-
-        let res = srv.call("srv").await;
-        assert!(res.is_ok());
-        assert_eq!(res.unwrap(), ("srv", ()));
-    }
-}
diff --git a/actix-service/src/apply.rs b/actix-service/src/apply.rs
index 9bf97bb4..7b8d6bee 100644
--- a/actix-service/src/apply.rs
+++ b/actix-service/src/apply.rs
@@ -5,7 +5,9 @@ use core::{
     task::{Context, Poll},
 };
 
-use futures_util::ready;
+
+use pin_project_lite::pin_project;
+use futures_core::ready;
 
 use super::{IntoService, IntoServiceFactory, Service, ServiceFactory};
 
@@ -160,17 +162,18 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct ApplyServiceFactoryResponse<SF, F, Fut, Req, In, Res, Err>
-where
-    SF: ServiceFactory<In, Error = Err>,
-    F: FnMut(Req, &mut SF::Service) -> Fut,
-    Fut: Future<Output = Result<Res, Err>>,
-{
-    #[pin]
-    fut: SF::Future,
-    wrap_fn: Option<F>,
-    _phantom: PhantomData<(Req, Res)>,
+pin_project! {
+    pub struct ApplyServiceFactoryResponse<SF, F, Fut, Req, In, Res, Err>
+    where
+        SF: ServiceFactory<In, Error = Err>,
+        F: FnMut(Req, &mut SF::Service) -> Fut,
+        Fut: Future<Output = Result<Res, Err>>,
+    {
+        #[pin]
+        fut: SF::Future,
+        wrap_fn: Option<F>,
+        _phantom: PhantomData<(Req, Res)>,
+    }
 }
 
 impl<SF, F, Fut, Req, In, Res, Err> ApplyServiceFactoryResponse<SF, F, Fut, Req, In, Res, Err>
diff --git a/actix-service/src/apply_cfg.rs b/actix-service/src/apply_cfg.rs
index 882bb3c5..3e111231 100644
--- a/actix-service/src/apply_cfg.rs
+++ b/actix-service/src/apply_cfg.rs
@@ -7,6 +7,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use crate::{Service, ServiceFactory};
 
 /// Convert `Fn(Config, &mut Service1) -> Future<Service2>` fn to a service factory.
@@ -158,37 +160,42 @@ where
         ApplyConfigServiceFactoryResponse {
             cfg: Some(cfg),
             store: self.srv.clone(),
-            state: State::A(self.srv.borrow().0.new_service(())),
+            state: State::A {
+                fut: self.srv.borrow().0.new_service(()),
+            },
         }
     }
 }
 
-#[pin_project::pin_project]
-struct ApplyConfigServiceFactoryResponse<SF, Req, F, Cfg, Fut, S>
-where
-    SF: ServiceFactory<Req, Config = ()>,
-    SF::InitError: From<SF::Error>,
-    F: FnMut(Cfg, &mut SF::Service) -> Fut,
-    Fut: Future<Output = Result<S, SF::InitError>>,
-    S: Service<Req>,
-{
-    cfg: Option<Cfg>,
-    store: Rc<RefCell<(SF, F)>>,
-    #[pin]
-    state: State<SF, Fut, S, Req>,
+pin_project! {
+    struct ApplyConfigServiceFactoryResponse<SF, Req, F, Cfg, Fut, S>
+    where
+        SF: ServiceFactory<Req, Config = ()>,
+        SF::InitError: From<SF::Error>,
+        F: FnMut(Cfg, &mut SF::Service) -> Fut,
+        Fut: Future<Output = Result<S, SF::InitError>>,
+        S: Service<Req>,
+    {
+        cfg: Option<Cfg>,
+        store: Rc<RefCell<(SF, F)>>,
+        #[pin]
+        state: State<SF, Fut, S, Req>,
+    }
 }
 
-#[pin_project::pin_project(project = StateProj)]
-enum State<SF, Fut, S, Req>
-where
-    SF: ServiceFactory<Req, Config = ()>,
-    SF::InitError: From<SF::Error>,
-    Fut: Future<Output = Result<S, SF::InitError>>,
-    S: Service<Req>,
-{
-    A(#[pin] SF::Future),
-    B(SF::Service),
-    C(#[pin] Fut),
+pin_project! {
+    #[project = StateProj]
+    enum State<SF, Fut, S, Req>
+    where
+        SF: ServiceFactory<Req, Config = ()>,
+        SF::InitError: From<SF::Error>,
+        Fut: Future<Output = Result<S, SF::InitError>>,
+        S: Service<Req>,
+    {
+        A { #[pin] fut: SF::Future },
+        B { svc: SF::Service },
+        C { #[pin] fut: Fut },
+    }
 }
 
 impl<SF, Req, F, Cfg, Fut, S> Future
@@ -206,25 +213,25 @@ where
         let mut this = self.as_mut().project();
 
         match this.state.as_mut().project() {
-            StateProj::A(fut) => match fut.poll(cx)? {
+            StateProj::A { fut } => match fut.poll(cx)? {
                 Poll::Pending => Poll::Pending,
-                Poll::Ready(srv) => {
-                    this.state.set(State::B(srv));
+                Poll::Ready(svc) => {
+                    this.state.set(State::B { svc });
                     self.poll(cx)
                 }
             },
-            StateProj::B(srv) => match srv.poll_ready(cx)? {
+            StateProj::B { svc } => match svc.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));
+                        let fut = f(this.cfg.take().unwrap(), svc);
+                        this.state.set(State::C { fut });
                     }
                     self.poll(cx)
                 }
                 Poll::Pending => Poll::Pending,
             },
-            StateProj::C(fut) => fut.poll(cx),
+            StateProj::C { fut } => fut.poll(cx),
         }
     }
 }
diff --git a/actix-service/src/lib.rs b/actix-service/src/lib.rs
index 38f1f167..d66d5221 100644
--- a/actix-service/src/lib.rs
+++ b/actix-service/src/lib.rs
@@ -16,7 +16,6 @@ use core::{
 };
 
 mod and_then;
-mod and_then_apply_fn;
 mod apply;
 mod apply_cfg;
 pub mod boxed;
diff --git a/actix-service/src/map.rs b/actix-service/src/map.rs
index 0c815298..a8afa25f 100644
--- a/actix-service/src/map.rs
+++ b/actix-service/src/map.rs
@@ -5,6 +5,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use super::{Service, ServiceFactory};
 
 /// Service for the `map` combinator, changing the type of a service's response.
@@ -61,15 +63,16 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct MapFuture<A, F, Req, Res>
-where
-    A: Service<Req>,
-    F: FnMut(A::Response) -> Res,
-{
-    f: F,
-    #[pin]
-    fut: A::Future,
+pin_project! {
+    pub struct MapFuture<A, F, Req, Res>
+    where
+        A: Service<Req>,
+        F: FnMut(A::Response) -> Res,
+    {
+        f: F,
+        #[pin]
+        fut: A::Future,
+    }
 }
 
 impl<A, F, Req, Res> MapFuture<A, F, Req, Res>
@@ -154,15 +157,16 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct MapServiceFuture<A, F, Req, Res>
-where
-    A: ServiceFactory<Req>,
-    F: FnMut(A::Response) -> Res,
-{
-    #[pin]
-    fut: A::Future,
-    f: Option<F>,
+pin_project! {
+    pub struct MapServiceFuture<A, F, Req, Res>
+    where
+        A: ServiceFactory<Req>,
+        F: FnMut(A::Response) -> Res,
+    {
+        #[pin]
+        fut: A::Future,
+        f: Option<F>,
+    }
 }
 
 impl<A, F, Req, Res> MapServiceFuture<A, F, Req, Res>
diff --git a/actix-service/src/map_err.rs b/actix-service/src/map_err.rs
index d4e94a8d..f0bf134b 100644
--- a/actix-service/src/map_err.rs
+++ b/actix-service/src/map_err.rs
@@ -5,6 +5,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use super::{Service, ServiceFactory};
 
 /// Service for the `map_err` combinator, changing the type of a service's
@@ -64,15 +66,16 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct MapErrFuture<A, Req, F, E>
-where
-    A: Service<Req>,
-    F: Fn(A::Error) -> E,
-{
-    f: F,
-    #[pin]
-    fut: A::Future,
+pin_project! {
+    pub struct MapErrFuture<A, Req, F, E>
+    where
+        A: Service<Req>,
+        F: Fn(A::Error) -> E,
+    {
+        f: F,
+        #[pin]
+        fut: A::Future,
+    }
 }
 
 impl<A, Req, F, E> MapErrFuture<A, Req, F, E>
@@ -159,15 +162,16 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct MapErrServiceFuture<A, Req, F, E>
-where
-    A: ServiceFactory<Req>,
-    F: Fn(A::Error) -> E,
-{
-    #[pin]
-    fut: A::Future,
-    f: F,
+pin_project! {
+    pub struct MapErrServiceFuture<A, Req, F, E>
+    where
+        A: ServiceFactory<Req>,
+        F: Fn(A::Error) -> E,
+    {
+        #[pin]
+        fut: A::Future,
+        f: F,
+    }
 }
 
 impl<A, Req, F, E> MapErrServiceFuture<A, Req, F, E>
diff --git a/actix-service/src/map_init_err.rs b/actix-service/src/map_init_err.rs
index b8ab5c42..9fc383aa 100644
--- a/actix-service/src/map_init_err.rs
+++ b/actix-service/src/map_init_err.rs
@@ -5,6 +5,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use super::ServiceFactory;
 
 /// `MapInitErr` service combinator
@@ -61,15 +63,16 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct MapInitErrFuture<A, F, Req, E>
-where
-    A: ServiceFactory<Req>,
-    F: Fn(A::InitError) -> E,
-{
-    f: F,
-    #[pin]
-    fut: A::Future,
+pin_project! {
+    pub struct MapInitErrFuture<A, F, Req, E>
+    where
+        A: ServiceFactory<Req>,
+        F: Fn(A::InitError) -> E,
+    {
+        f: F,
+        #[pin]
+        fut: A::Future,
+    }
 }
 
 impl<A, F, Req, E> MapInitErrFuture<A, F, Req, E>
diff --git a/actix-service/src/pipeline.rs b/actix-service/src/pipeline.rs
index a09039b7..580d7b4c 100644
--- a/actix-service/src/pipeline.rs
+++ b/actix-service/src/pipeline.rs
@@ -1,11 +1,9 @@
 use core::{
-    future::Future,
     marker::PhantomData,
     task::{Context, Poll},
 };
 
 use crate::and_then::{AndThenService, AndThenServiceFactory};
-use crate::and_then_apply_fn::{AndThenApplyFn, AndThenApplyFnFactory};
 use crate::map::{Map, MapServiceFactory};
 use crate::map_err::{MapErr, MapErrServiceFactory};
 use crate::map_init_err::MapInitErr;
@@ -70,28 +68,6 @@ where
         }
     }
 
-    /// Apply function to specified service and use it as a next service in chain.
-    ///
-    /// Short version of `pipeline_factory(...).and_then(apply_fn(...))`
-    pub fn and_then_apply_fn<I, S1, F, Fut, In, Res, Err>(
-        self,
-        service: I,
-        wrap_fn: F,
-    ) -> Pipeline<impl Service<Req, Response = Res, Error = Err> + Clone, Req>
-    where
-        Self: Sized,
-        I: IntoService<S1, In>,
-        S1: Service<In>,
-        F: FnMut(S::Response, &mut S1) -> Fut,
-        Fut: Future<Output = Result<Res, Err>>,
-        Err: From<S::Error> + From<S1::Error>,
-    {
-        Pipeline {
-            service: AndThenApplyFn::new(self.service, service.into_service(), wrap_fn),
-            _phantom: PhantomData,
-        }
-    }
-
     /// Chain on a computation for when a call to the service finished,
     /// passing the result of the call to the next service `U`.
     ///
@@ -222,39 +198,6 @@ where
         }
     }
 
-    /// Apply function to specified service and use it as a next service in chain.
-    ///
-    /// Short version of `pipeline_factory(...).and_then(apply_fn_factory(...))`
-    pub fn and_then_apply_fn<I, SF1, Fut, F, In, Res, Err>(
-        self,
-        factory: I,
-        wrap_fn: F,
-    ) -> PipelineFactory<
-        impl ServiceFactory<
-                Req,
-                Response = Res,
-                Error = Err,
-                Config = SF::Config,
-                InitError = SF::InitError,
-                Service = impl Service<Req, Response = Res, Error = Err> + Clone,
-            > + Clone,
-        Req,
-    >
-    where
-        Self: Sized,
-        SF::Config: Clone,
-        I: IntoServiceFactory<SF1, In>,
-        SF1: ServiceFactory<In, Config = SF::Config, InitError = SF::InitError>,
-        F: FnMut(SF::Response, &mut SF1::Service) -> Fut + Clone,
-        Fut: Future<Output = Result<Res, Err>>,
-        Err: From<SF::Error> + From<SF1::Error>,
-    {
-        PipelineFactory {
-            factory: AndThenApplyFnFactory::new(self.factory, factory.into_factory(), wrap_fn),
-            _phantom: PhantomData,
-        }
-    }
-
     /// 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 `U`.
diff --git a/actix-service/src/then.rs b/actix-service/src/then.rs
index 2de5a60d..179713ac 100644
--- a/actix-service/src/then.rs
+++ b/actix-service/src/then.rs
@@ -7,6 +7,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use super::{Service, ServiceFactory};
 
 /// Service for the `then` combinator, chaining a computation onto the end of
@@ -53,30 +55,36 @@ where
 
     fn call(&mut self, req: Req) -> Self::Future {
         ThenServiceResponse {
-            state: State::A(self.0.borrow_mut().0.call(req), Some(self.0.clone())),
+            state: State::A {
+                fut: self.0.borrow_mut().0.call(req),
+                b: Some(self.0.clone()),
+            },
         }
     }
 }
 
-#[pin_project::pin_project]
-pub(crate) struct ThenServiceResponse<A, B, Req>
-where
-    A: Service<Req>,
-    B: Service<Result<A::Response, A::Error>>,
-{
-    #[pin]
-    state: State<A, B, Req>,
+pin_project! {
+    pub(crate) struct ThenServiceResponse<A, B, Req>
+    where
+        A: Service<Req>,
+        B: Service<Result<A::Response, A::Error>>,
+    {
+        #[pin]
+        state: State<A, B, Req>,
+    }
 }
 
-#[pin_project::pin_project(project = StateProj)]
-enum State<A, B, Req>
-where
-    A: Service<Req>,
-    B: Service<Result<A::Response, A::Error>>,
-{
-    A(#[pin] A::Future, Option<Rc<RefCell<(A, B)>>>),
-    B(#[pin] B::Future),
-    Empty,
+pin_project! {
+    #[project = StateProj]
+    enum State<A, B, Req>
+    where
+        A: Service<Req>,
+        B: Service<Result<A::Response, A::Error>>,
+    {
+        A { #[pin] fut: A::Future, b: Option<Rc<RefCell<(A, B)>>> },
+        B { #[pin] fut: B::Future },
+        Empty,
+    }
 }
 
 impl<A, B, Req> Future for ThenServiceResponse<A, B, Req>
@@ -90,17 +98,17 @@ where
         let mut this = self.as_mut().project();
 
         match this.state.as_mut().project() {
-            StateProj::A(fut, b) => match fut.poll(cx) {
+            StateProj::A { fut, b } => match fut.poll(cx) {
                 Poll::Ready(res) => {
                     let b = b.take().unwrap();
                     this.state.set(State::Empty); // drop fut A
                     let fut = b.borrow_mut().1.call(res);
-                    this.state.set(State::B(fut));
+                    this.state.set(State::B { fut });
                     self.poll(cx)
                 }
                 Poll::Pending => Poll::Pending,
             },
-            StateProj::B(fut) => fut.poll(cx).map(|r| {
+            StateProj::B { fut } => fut.poll(cx).map(|r| {
                 this.state.set(State::Empty);
                 r
             }),
@@ -162,23 +170,24 @@ impl<A, B, Req> Clone for ThenServiceFactory<A, B, Req> {
     }
 }
 
-#[pin_project::pin_project]
-pub(crate) struct ThenServiceFactoryResponse<A, B, Req>
-where
-    A: ServiceFactory<Req>,
-    B: ServiceFactory<
-        Result<A::Response, A::Error>,
-        Config = A::Config,
-        Error = A::Error,
-        InitError = A::InitError,
-    >,
-{
-    #[pin]
-    fut_b: B::Future,
-    #[pin]
-    fut_a: A::Future,
-    a: Option<A::Service>,
-    b: Option<B::Service>,
+pin_project! {
+    pub(crate) struct ThenServiceFactoryResponse<A, B, Req>
+    where
+        A: ServiceFactory<Req>,
+        B: ServiceFactory<
+            Result<A::Response, A::Error>,
+            Config = A::Config,
+            Error = A::Error,
+            InitError = A::InitError,
+        >,
+    {
+        #[pin]
+        fut_b: B::Future,
+        #[pin]
+        fut_a: A::Future,
+        a: Option<A::Service>,
+        b: Option<B::Service>,
+    }
 }
 
 impl<A, B, Req> ThenServiceFactoryResponse<A, B, Req>
diff --git a/actix-service/src/transform.rs b/actix-service/src/transform.rs
index 602e7f54..76e4547a 100644
--- a/actix-service/src/transform.rs
+++ b/actix-service/src/transform.rs
@@ -6,6 +6,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use crate::transform_err::TransformMapInitErr;
 use crate::{IntoServiceFactory, Service, ServiceFactory};
 
@@ -187,30 +189,35 @@ where
     fn new_service(&self, cfg: S::Config) -> Self::Future {
         ApplyTransformFuture {
             store: self.0.clone(),
-            state: ApplyTransformFutureState::A(self.0.as_ref().1.new_service(cfg)),
+            state: ApplyTransformFutureState::A {
+                fut: self.0.as_ref().1.new_service(cfg),
+            },
         }
     }
 }
 
-#[pin_project::pin_project]
-pub struct ApplyTransformFuture<T, S, Req>
-where
-    S: ServiceFactory<Req>,
-    T: Transform<S::Service, Req, InitError = S::InitError>,
-{
-    store: Rc<(T, S)>,
-    #[pin]
-    state: ApplyTransformFutureState<T, S, Req>,
+pin_project! {
+    pub struct ApplyTransformFuture<T, S, Req>
+    where
+        S: ServiceFactory<Req>,
+        T: Transform<S::Service, Req, InitError = S::InitError>,
+    {
+        store: Rc<(T, S)>,
+        #[pin]
+        state: ApplyTransformFutureState<T, S, Req>,
+    }
 }
 
-#[pin_project::pin_project(project = ApplyTransformFutureStateProj)]
-pub enum ApplyTransformFutureState<T, S, Req>
-where
-    S: ServiceFactory<Req>,
-    T: Transform<S::Service, Req, InitError = S::InitError>,
-{
-    A(#[pin] S::Future),
-    B(#[pin] T::Future),
+pin_project! {
+    #[project = ApplyTransformFutureStateProj]
+    pub enum ApplyTransformFutureState<T, S, Req>
+    where
+        S: ServiceFactory<Req>,
+        T: Transform<S::Service, Req, InitError = S::InitError>,
+    {
+        A { #[pin] fut: S::Future },
+        B { #[pin] fut: T::Future },
+    }
 }
 
 impl<T, S, Req> Future for ApplyTransformFuture<T, S, Req>
@@ -224,15 +231,15 @@ where
         let mut this = self.as_mut().project();
 
         match this.state.as_mut().project() {
-            ApplyTransformFutureStateProj::A(fut) => match fut.poll(cx)? {
+            ApplyTransformFutureStateProj::A { fut } => match fut.poll(cx)? {
                 Poll::Ready(srv) => {
                     let fut = this.store.0.new_transform(srv);
-                    this.state.set(ApplyTransformFutureState::B(fut));
+                    this.state.set(ApplyTransformFutureState::B { fut });
                     self.poll(cx)
                 }
                 Poll::Pending => Poll::Pending,
             },
-            ApplyTransformFutureStateProj::B(fut) => fut.poll(cx),
+            ApplyTransformFutureStateProj::B { fut } => fut.poll(cx),
         }
     }
 }
diff --git a/actix-service/src/transform_err.rs b/actix-service/src/transform_err.rs
index 355f2720..cbf5fe3b 100644
--- a/actix-service/src/transform_err.rs
+++ b/actix-service/src/transform_err.rs
@@ -5,6 +5,8 @@ use core::{
     task::{Context, Poll},
 };
 
+use pin_project_lite::pin_project;
+
 use super::Transform;
 
 /// Transform for the `map_init_err` combinator, changing the type of a new
@@ -65,15 +67,16 @@ where
     }
 }
 
-#[pin_project::pin_project]
-pub struct TransformMapInitErrFuture<T, S, F, E, Req>
-where
+pin_project! {
+    pub struct TransformMapInitErrFuture<T, S, F, E, Req>
+    where
     T: Transform<S, Req>,
     F: Fn(T::InitError) -> E,
-{
-    #[pin]
-    fut: T::Future,
-    f: F,
+    {
+        #[pin]
+        fut: T::Future,
+        f: F,
+    }
 }
 
 impl<T, S, F, E, Req> Future for TransformMapInitErrFuture<T, S, F, E, Req>