improve boxed service docs

actix-service/Cargo.toml

@@ -22,8 +22,10 @@ path = "src/lib.rs"
 
 [dependencies]
 futures-core = { version = "0.3.7", default-features = false }
+paste = "1"
 pin-project-lite = "0.2"
 
 [dev-dependencies]
 actix-rt = "2.0.0"
+actix-utils = "3.0.0-beta.4"
 futures-util = { version = "0.3.7", default-features = false }

actix-service/src/boxed.rs

@@ -3,26 +3,30 @@
 use alloc::{boxed::Box, rc::Rc};
 use core::{future::Future, pin::Pin};
 
+use paste::paste;
+
 use crate::{Service, ServiceFactory};
 
-/// A boxed future without a Send bound or lifetime parameters.
+/// A boxed future with no send bound or lifetime parameters.
 pub type BoxFuture<T> = Pin<Box<dyn Future<Output = T>>>;
 
 macro_rules! service_object {
     ($name: ident, $type: tt, $fn_name: ident) => {
-        /// Type alias for service trait object.
+        paste! {
-        pub type $name<Req, Res, Err> = $type<
+            #[doc = "Type alias for service trait object using `" $type "`."]
-            dyn Service<Req, Response = Res, Error = Err, Future = BoxFuture<Result<Res, Err>>>,
+            pub type $name<Req, Res, Err> = $type<
-        >;
+                dyn Service<Req, Response = Res, Error = Err, Future = BoxFuture<Result<Res, Err>>>,
+            >;
 
-        /// Create service trait object.
+            #[doc = "Wraps service as a trait object using [`" $name "`]."]
-        pub fn $fn_name<S, Req>(service: S) -> $name<Req, S::Response, S::Error>
+            pub fn $fn_name<S, Req>(service: S) -> $name<Req, S::Response, S::Error>
-        where
+            where
-            S: Service<Req> + 'static,
+                S: Service<Req> + 'static,
-            Req: 'static,
+                Req: 'static,
-            S::Future: 'static,
+                S::Future: 'static,
-        {
+            {
-            $type::new(ServiceWrapper::new(service))
+                $type::new(ServiceWrapper::new(service))
+            }
         }
     };
 }
@@ -56,10 +60,10 @@ where
     }
 }
 
-/// Wrapper for a service factory trait object that will produce a boxed trait object service.
+/// Wrapper for a service factory that will map it's services to boxed trait object services.
 pub struct BoxServiceFactory<Cfg, Req, Res, Err, InitErr>(Inner<Cfg, Req, Res, Err, InitErr>);
 
-/// Create service factory trait object.
+/// Wraps a service factory that returns service trait objects.
 pub fn factory<SF, Req>(
     factory: SF,
 ) -> BoxServiceFactory<SF::Config, Req, SF::Response, SF::Error, SF::InitError>

actix-service/src/lib.rs

@@ -73,7 +73,7 @@ use self::ready::{err, ok, ready, Ready};
 /// impl Service<u8> for MyService {
 ///      type Response = u64;
 ///      type Error = MyError;
-///      type Future = Pin<Box<Future<Output=Result<Self::Response, Self::Error>>>>;
+///      type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>>>>;
 ///
 ///      fn poll_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { ... }
 ///
@@ -82,7 +82,7 @@ use self::ready::{err, ok, ready, Ready};
 /// ```
 ///
 /// Sometimes it is not necessary to implement the Service trait. For example, the above service
-/// could be rewritten as a simple function and passed to [fn_service](fn_service()).
+/// could be rewritten as a simple function and passed to [`fn_service`](fn_service()).
 ///
 /// ```ignore
 /// async fn my_service(req: u8) -> Result<u64, MyError>;
@@ -102,13 +102,12 @@ pub trait Service<Req> {
 
     /// Returns `Ready` when the service is able to process requests.
     ///
-    /// If the service is at capacity, then `Pending` is returned and the task
+    /// If the service is at capacity, then `Pending` is returned and the task is notified when the
-    /// is notified when the service becomes ready again. This function is
+    /// service becomes ready again. This function is expected to be called while on a task.
-    /// expected to be called while on a task.
     ///
-    /// This is a **best effort** implementation. False positives are permitted.
+    /// This is a best effort implementation. False positives are permitted. It is permitted for
-    /// It is permitted for the service to return `Ready` from a `poll_ready`
+    /// the service to return `Ready` from a `poll_ready` call and the next invocation of `call`
-    /// call and the next invocation of `call` results in an error.
+    /// results in an error.
     ///
     /// # Notes
     /// 1. `poll_ready` might be called on a different task to `call`.
@@ -117,25 +116,26 @@ pub trait Service<Req> {
 
     /// Process the request and return the response asynchronously.
     ///
-    /// This function is expected to be callable off task. As such,
+    /// This function is expected to be callable off-task. As such, implementations of `call` should
-    /// implementations should take care to not call `poll_ready`. If the
+    /// take care to not call `poll_ready`. If the service is at capacity and the request is unable
-    /// service is at capacity and the request is unable to be handled, the
+    /// to be handled, the returned `Future` should resolve to an error.
-    /// returned `Future` should resolve to an error.
     ///
-    /// Calling `call` without calling `poll_ready` is permitted. The
+    /// Invoking `call` without first invoking `poll_ready` is permitted. Implementations must be
-    /// implementation must be resilient to this fact.
+    /// resilient to this fact.
     fn call(&self, req: Req) -> Self::Future;
 }
 
 /// Factory for creating `Service`s.
 ///
-/// Acts as a service factory. This is useful for cases where new `Service`s
+/// This is useful for cases where new `Service`s must be produced. One case is a TCP
-/// must be produced. One case is a TCP server listener. The listener
+/// server listener: a listener accepts new connections, constructs a new `Service` for each using
-/// accepts new TCP streams, obtains a new `Service` using the
+/// the `ServiceFactory` trait, and uses the new `Service` to process inbound requests on that new
-/// `ServiceFactory` trait, and uses the new `Service` to process inbound
+/// connection.
-/// requests on that new TCP stream.
 ///
 /// `Config` is a service factory configuration type.
+///
+/// Simple factories may be able to use [`fn_factory`] or [`fn_factory_with_config`] to
+/// reduce boilerplate.
 pub trait ServiceFactory<Req> {
     /// Responses given by the created services.
     type Response;

actix-service/src/transform.rs

@@ -222,10 +222,9 @@ where
 
 #[cfg(test)]
 mod tests {
-    use core::{
+    use core::time::Duration;
-        future::{ready, Ready},
+
-        time::Duration,
+    use actix_utils::future::{ready, Ready};
-    };
 
     use super::*;
     use crate::Service;