update utils; add NewTransform::map_init_err

actix-service/Cargo.toml

@@ -24,3 +24,4 @@ path = "src/lib.rs"
 
 [dependencies]
 futures = "0.1.24"
+void = "1.0.2"

actix-service/src/fn_service.rs

@@ -3,7 +3,7 @@ use std::marker::PhantomData;
 use futures::future::{ok, FutureResult};
 use futures::{Async, IntoFuture, Poll};
 
-use crate::Never;
+use crate::Void;
 use crate::{IntoConfigurableNewService, IntoNewService, IntoService, NewService, Service};
 
 /// Create `NewService` for function that can act as Service
@@ -125,7 +125,7 @@ where
     type Error = Out::Error;
     type Service = FnService<F, Req, Out>;
 
-    type InitError = Never;
+    type InitError = Void;
     type Future = FutureResult<Self::Service, Self::InitError>;
 
     fn new_service(&self, _: &Cfg) -> Self::Future {

actix-service/src/lib.rs

@@ -3,6 +3,8 @@ use std::sync::Arc;
 
 use futures::{Future, IntoFuture, Poll};
 
+pub use void::Void;
+
 mod and_then;
 mod and_then_apply;
 mod and_then_apply_fn;
@@ -19,6 +21,7 @@ mod map_init_err;
 mod then;
 mod transform;
 mod transform_map_err;
+mod transform_map_init_err;
 
 pub use self::and_then::{AndThen, AndThenNewService};
 use self::and_then_apply::{AndThenTransform, AndThenTransformNewService};
@@ -33,9 +36,6 @@ pub use self::map_init_err::MapInitErr;
 pub use self::then::{Then, ThenNewService};
 pub use self::transform::{IntoNewTransform, IntoTransform, NewTransform, Transform};
 
-#[derive(Copy, Clone, Debug)]
-pub enum Never {}
-
 /// An asynchronous function from `Request` to a `Response`.
 pub trait Service {
     /// Requests handled by the service.

actix-service/src/transform.rs

@@ -4,6 +4,7 @@ use std::sync::Arc;
 use futures::{Future, Poll};
 
 use crate::transform_map_err::{TransformMapErr, TransformMapErrNewTransform};
+use crate::transform_map_init_err::TransformMapInitErr;
 use crate::Service;
 
 /// An asynchronous function for transforming service call result.
@@ -85,6 +86,16 @@ pub trait NewTransform<Service, Config = ()> {
     {
         TransformMapErrNewTransform::new(self, f)
     }
+
+    /// Map this service's factory init error to a different error,
+    /// returning a new transform service factory.
+    fn map_init_err<F, E>(self, f: F) -> TransformMapInitErr<Self, Service, Config, F, E>
+    where
+        Self: Sized,
+        F: Fn(Self::InitError) -> E,
+    {
+        TransformMapInitErr::new(self, f)
+    }
 }
 
 impl<'a, T, S> Transform<S> for &'a mut T

actix-service/src/transform_map_init_err.rs

@@ -0,0 +1,94 @@
+use std::marker::PhantomData;
+
+use futures::{Future, Poll};
+
+use super::NewTransform;
+
+/// NewTransform for the `map_init_err` combinator, changing the type of a new
+/// transform's error.
+///
+/// This is created by the `NewTransform::map_init_err` method.
+pub struct TransformMapInitErr<T, S, C, F, E> {
+    t: T,
+    f: F,
+    e: PhantomData<(S, C, E)>,
+}
+
+impl<T, S, C, F, E> TransformMapInitErr<T, S, C, F, E> {
+    /// Create new `MapInitErr` new transform instance
+    pub fn new(t: T, f: F) -> Self
+    where
+        T: NewTransform<S, C>,
+        F: Fn(T::InitError) -> E,
+    {
+        Self {
+            t,
+            f,
+            e: PhantomData,
+        }
+    }
+}
+
+impl<T, S, C, F, E> Clone for TransformMapInitErr<T, S, C, F, E>
+where
+    T: Clone,
+    F: Clone,
+{
+    fn clone(&self) -> Self {
+        Self {
+            t: self.t.clone(),
+            f: self.f.clone(),
+            e: PhantomData,
+        }
+    }
+}
+
+impl<T, S, C, F, E> NewTransform<S, C> for TransformMapInitErr<T, S, C, F, E>
+where
+    T: NewTransform<S, C>,
+    F: Fn(T::InitError) -> E + Clone,
+{
+    type Request = T::Request;
+    type Response = T::Response;
+    type Error = T::Error;
+    type Transform = T::Transform;
+
+    type InitError = E;
+    type Future = TransformMapInitErrFuture<T, S, C, F, E>;
+
+    fn new_transform(&self, cfg: &C) -> Self::Future {
+        TransformMapInitErrFuture::new(self.t.new_transform(cfg), self.f.clone())
+    }
+}
+
+pub struct TransformMapInitErrFuture<T, S, C, F, E>
+where
+    T: NewTransform<S, C>,
+    F: Fn(T::InitError) -> E,
+{
+    fut: T::Future,
+    f: F,
+}
+
+impl<T, S, C, F, E> TransformMapInitErrFuture<T, S, C, F, E>
+where
+    T: NewTransform<S, C>,
+    F: Fn(T::InitError) -> E,
+{
+    fn new(fut: T::Future, f: F) -> Self {
+        TransformMapInitErrFuture { f, fut }
+    }
+}
+
+impl<T, S, C, F, E> Future for TransformMapInitErrFuture<T, S, C, F, E>
+where
+    T: NewTransform<S, C>,
+    F: Fn(T::InitError) -> E + Clone,
+{
+    type Item = T::Transform;
+    type Error = E;
+
+    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+        self.fut.poll().map_err(|e| (self.f)(e))
+    }
+}