Move layer::{LayerExt, Chain, Identity} (#216)

- `tower-layer` util types are now in `tower-util`.
- `LayerExt` is now in `tower`.

This sets the stage for adding layer specific extension fns.

tower-layer/Cargo.toml

@@ -22,7 +22,3 @@ tower-service = "0.2.0"
 
 [dev-dependencies]
 void = "1"
-
-[features]
-default = ["util"]
-util = []

tower-layer/src/lib.rs

@@ -1,3 +1,6 @@
+#![deny(missing_docs)]
+#![doc(html_root_url = "https://docs.rs/tower-layer/0.1.0")]
+
 //! Layer traits and extensions.
 //!
 //! A layer decorates an service and provides additional functionality. It
@@ -5,18 +8,9 @@
 //!
 //! A middleware implements the [`Layer`] and [`Service`] trait.
 
-#![deny(missing_docs)]
-#![doc(html_root_url = "https://docs.rs/tower-layer/0.1.0")]
-
 extern crate futures;
 extern crate tower_service;
 
-#[cfg(feature = "util")]
-pub mod util;
-
-#[cfg(feature = "util")]
-pub use util::LayerExt;
-
 use tower_service::Service;
 
 /// Decorates a `Service`, transforming either the request or the response.

tower-layer/src/util/mod.rs

@@ -1,27 +0,0 @@
-//! Types and utilities for working with `Layer`.
-
-use Layer;
-
-mod chain;
-mod identity;
-
-pub use self::chain::Chain;
-pub use self::identity::Identity;
-
-/// An extension trait for `Layer`'s that provides a variety of convenient
-/// adapters.
-pub trait LayerExt<S, Request>: Layer<S, Request> {
-    /// Return a new `Layer` instance that applies both `self` and
-    /// `middleware` to services being wrapped.
-    ///
-    /// This defines a middleware stack.
-    fn chain<T>(self, middleware: T) -> Chain<Self, T>
-    where
-        T: Layer<Self::Service, Request>,
-        Self: Sized,
-    {
-        Chain::new(self, middleware)
-    }
-}
-
-impl<T, S, Request> LayerExt<S, Request> for T where T: Layer<S, Request> {}

tower-util/Cargo.toml

@@ -24,8 +24,9 @@ io = ["tokio-io"]
 [dependencies]
 either = { version = "1.5.1", optional = true }
 futures = "0.1.23"
-tower-service = "0.2.0"
 tokio-io = { version = "0.1.12", optional = true }
+tower-service = "0.2.0"
+tower-layer = { version = "0.1.0", path = "../tower-layer" }
 
 [dev-dependencies]
 tokio-mock-task = "0.1"

tower-util/src/layer/chain.rs

@@ -1,5 +1,5 @@
+use tower_layer::Layer;
 use tower_service::Service;
-use Layer;
 
 /// Two middlewares chained together.
 ///

tower-util/src/layer/identity.rs

@@ -1,6 +1,6 @@
 use std::fmt;
+use tower_layer::Layer;
 use tower_service::Service;
-use Layer;
 
 /// A no-op middleware.
 ///

tower-util/src/layer/mod.rs

@@ -0,0 +1,5 @@
+mod chain;
+mod identity;
+
+pub use self::chain::Chain;
+pub use self::identity::Identity;

tower-util/src/lib.rs

@@ -6,12 +6,14 @@ extern crate either as _either;
 extern crate futures;
 #[cfg(feature = "io")]
 extern crate tokio_io;
+extern crate tower_layer;
 extern crate tower_service;
 
 mod boxed;
 mod call_all;
 #[cfg(feature = "either")]
 mod either;
+pub mod layer;
 #[cfg(feature = "io")]
 mod make_connection;
 mod make_service;

tower/src/builder/mod.rs

@@ -4,11 +4,9 @@ mod service;
 
 pub use self::service::{LayeredMakeService, ServiceFuture};
 
-use tower_layer::{
-    util::{Chain, Identity},
-    Layer,
-};
+use tower_layer::Layer;
 use tower_service::Service;
+use tower_util::layer::{Chain, Identity};
 use tower_util::MakeService;
 
 pub(super) type Error = Box<::std::error::Error + Send + Sync>;

tower/src/layer.rs

@@ -7,3 +7,24 @@ pub use tower_load_shed::LoadShedLayer;
 pub use tower_rate_limit::RateLimitLayer;
 pub use tower_retry::RetryLayer;
 pub use tower_timeout::TimeoutLayer;
+
+use tower_layer::Layer;
+use tower_util::layer::Chain;
+
+/// An extension trait for `Layer`'s that provides a variety of convenient
+/// adapters.
+pub trait LayerExt<S, Request>: Layer<S, Request> {
+    /// Return a new `Layer` instance that applies both `self` and
+    /// `middleware` to services being wrapped.
+    ///
+    /// This defines a middleware stack.
+    fn chain<T>(self, middleware: T) -> Chain<Self, T>
+    where
+        T: Layer<Self::Service, Request>,
+        Self: Sized,
+    {
+        Chain::new(self, middleware)
+    }
+}
+
+impl<T, S, Request> LayerExt<S, Request> for T where T: Layer<S, Request> {}