From 629ef23371d056e628a152141c65d7f648c2b7a6 Mon Sep 17 00:00:00 2001
From: Nikolay Kim <fafhrd91@gmail.com>
Date: Sat, 9 Mar 2019 09:01:02 -0800
Subject: [PATCH] add .apply_cfg new service combinator

---
 actix-service/CHANGES.md       |   5 +-
 actix-service/src/apply_cfg.rs | 163 +++++++++++++++++++++++++++++++++
 actix-service/src/lib.rs       |  21 ++++-
 3 files changed, 187 insertions(+), 2 deletions(-)
 create mode 100644 actix-service/src/apply_cfg.rs

diff --git a/actix-service/CHANGES.md b/actix-service/CHANGES.md
index 6df36058..881667b2 100644
--- a/actix-service/CHANGES.md
+++ b/actix-service/CHANGES.md
@@ -1,11 +1,14 @@
 # Changes
 
-## [0.3.2] - 2019-03-xx
+## [0.3.3] - 2019-03-xx
 
 ### Added
 
 * Add `ApplyTransform` new service for transform and new service.
 
+* Add `NewService::apply_cfg()` combinator, it allows to use
+  nested `NewService` with different config parameter.
+
 ### Changed
 
 * Revert IntoFuture change
diff --git a/actix-service/src/apply_cfg.rs b/actix-service/src/apply_cfg.rs
new file mode 100644
index 00000000..a96663ea
--- /dev/null
+++ b/actix-service/src/apply_cfg.rs
@@ -0,0 +1,163 @@
+use std::marker::PhantomData;
+
+use futures::{Async, Future, Poll};
+
+use crate::and_then::AndThen;
+use crate::{IntoNewService, NewService};
+
+/// `ApplyNewService` new service combinator
+pub struct ApplyConfig<F, A, B, C1, C2> {
+    a: A,
+    b: B,
+    f: F,
+    r: PhantomData<(C1, C2)>,
+}
+
+impl<F, A, B, C1, C2> ApplyConfig<F, A, B, C1, C2>
+where
+    A: NewService<C1>,
+    B: NewService<C2, Request = A::Response, Error = A::Error, InitError = A::InitError>,
+    F: Fn(&C1) -> C2,
+{
+    /// Create new `ApplyNewService` new service instance
+    pub fn new<A1: IntoNewService<A, C1>, B1: IntoNewService<B, C2>>(
+        a: A1,
+        b: B1,
+        f: F,
+    ) -> Self {
+        Self {
+            f,
+            a: a.into_new_service(),
+            b: b.into_new_service(),
+            r: PhantomData,
+        }
+    }
+}
+
+impl<F, A, B, C1, C2> Clone for ApplyConfig<F, A, B, C1, C2>
+where
+    A: Clone,
+    B: Clone,
+    F: Clone,
+{
+    fn clone(&self) -> Self {
+        Self {
+            a: self.a.clone(),
+            b: self.b.clone(),
+            f: self.f.clone(),
+            r: PhantomData,
+        }
+    }
+}
+
+impl<F, A, B, C1, C2> NewService<C1> for ApplyConfig<F, A, B, C1, C2>
+where
+    A: NewService<C1>,
+    B: NewService<C2, Request = A::Response, Error = A::Error, InitError = A::InitError>,
+    F: Fn(&C1) -> C2,
+{
+    type Request = A::Request;
+    type Response = B::Response;
+    type Error = A::Error;
+    type Service = AndThen<A::Service, B::Service>;
+
+    type InitError = A::InitError;
+    type Future = ApplyConfigResponse<A, B, C1, C2>;
+
+    fn new_service(&self, cfg: &C1) -> Self::Future {
+        let cfg2 = (self.f)(cfg);
+
+        ApplyConfigResponse {
+            a: None,
+            b: None,
+            fut_a: self.a.new_service(cfg),
+            fut_b: self.b.new_service(&cfg2),
+        }
+    }
+}
+
+pub struct ApplyConfigResponse<A, B, C1, C2>
+where
+    A: NewService<C1>,
+    B: NewService<C2>,
+{
+    fut_b: B::Future,
+    fut_a: A::Future,
+    a: Option<A::Service>,
+    b: Option<B::Service>,
+}
+
+impl<A, B, C1, C2> Future for ApplyConfigResponse<A, B, C1, C2>
+where
+    A: NewService<C1>,
+    B: NewService<C2, Request = A::Response, Error = A::Error, InitError = A::InitError>,
+{
+    type Item = AndThen<A::Service, B::Service>;
+    type Error = A::InitError;
+
+    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+        if self.a.is_none() {
+            if let Async::Ready(service) = self.fut_a.poll()? {
+                self.a = Some(service);
+            }
+        }
+
+        if self.b.is_none() {
+            if let Async::Ready(service) = self.fut_b.poll()? {
+                self.b = Some(service);
+            }
+        }
+
+        if self.a.is_some() && self.b.is_some() {
+            Ok(Async::Ready(AndThen::new(
+                self.a.take().unwrap(),
+                self.b.take().unwrap(),
+            )))
+        } else {
+            Ok(Async::NotReady)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use futures::future::{ok, FutureResult};
+    use futures::{Async, Future, Poll};
+
+    use crate::{fn_cfg_factory, NewService, Service};
+
+    #[derive(Clone)]
+    struct Srv;
+    impl Service for Srv {
+        type Request = ();
+        type Response = ();
+        type Error = ();
+        type Future = FutureResult<(), ()>;
+
+        fn poll_ready(&mut self) -> Poll<(), Self::Error> {
+            Ok(Async::Ready(()))
+        }
+
+        fn call(&mut self, _: ()) -> Self::Future {
+            ok(())
+        }
+    }
+
+    #[test]
+    fn test_new_service() {
+        let new_srv = fn_cfg_factory(|_: &usize| Ok::<_, ()>(Srv)).apply_cfg(
+            fn_cfg_factory(|s: &String| {
+                assert_eq!(s, "test");
+                Ok::<_, ()>(Srv)
+            }),
+            |cfg: &usize| {
+                assert_eq!(*cfg, 1);
+                "test".to_string()
+            },
+        );
+
+        if let Async::Ready(mut srv) = new_srv.new_service(&1).poll().unwrap() {
+            assert!(srv.poll_ready().is_ok());
+        }
+    }
+}
diff --git a/actix-service/src/lib.rs b/actix-service/src/lib.rs
index 8dfc6b22..c0d61908 100644
--- a/actix-service/src/lib.rs
+++ b/actix-service/src/lib.rs
@@ -9,6 +9,7 @@ mod and_then;
 mod and_then_apply;
 mod and_then_apply_fn;
 mod apply;
+mod apply_cfg;
 pub mod blank;
 pub mod boxed;
 mod cell;
@@ -26,6 +27,7 @@ pub use self::and_then::{AndThen, AndThenNewService};
 use self::and_then_apply::AndThenTransform;
 use self::and_then_apply_fn::{AndThenApply, AndThenApplyNewService};
 pub use self::apply::{Apply, ApplyNewService};
+use self::apply_cfg::ApplyConfig;
 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};
@@ -204,7 +206,7 @@ pub trait NewService<Config = ()> {
     /// 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
+    /// Apply transform service to specified service and use it as a next service in
     /// chain.
     fn apply<T, T1, B, B1>(
         self,
@@ -240,6 +242,23 @@ pub trait NewService<Config = ()> {
         AndThenApplyNewService::new(self, service, f)
     }
 
+    /// Map this service's config type to a different config,
+    /// and use for nested service
+    fn apply_cfg<F, C, B, B1>(self, service: B1, f: F) -> ApplyConfig<F, Self, B, Config, C>
+    where
+        Self: Sized,
+        F: Fn(&Config) -> C,
+        B1: IntoNewService<B, C>,
+        B: NewService<
+            C,
+            Request = Self::Response,
+            Error = Self::Error,
+            InitError = Self::InitError,
+        >,
+    {
+        ApplyConfig::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