Use 'futures::future::BoxFuture' instead of 'Pin<Box<...>>' for readability.

core/lib/src/catcher.rs

@@ -154,7 +154,7 @@ macro_rules! default_catchers {
         let mut map = HashMap::new();
 
         $(
-            fn $fn_name<'r>(req: &'r Request<'_>) -> std::pin::Pin<Box<dyn std::future::Future<Output = response::Result<'r>> + Send + 'r>> {
+            fn $fn_name<'r>(req: &'r Request<'_>) -> futures::future::BoxFuture<'r, response::Result<'r>> {
                 status::Custom(Status::from_code($code).unwrap(),
                     content::Html(error_page_template!($code, $name, $description))
                 ).respond_to(req)

core/lib/src/codegen.rs

@@ -1,11 +1,11 @@
-use futures::future::Future;
+use futures::future::BoxFuture;
 
 use crate::{Request, Data};
 use crate::handler::{Outcome, ErrorHandler};
 use crate::http::{Method, MediaType};
 
 /// Type of a static handler, which users annotate with Rocket's attribute.
-pub type StaticHandler = for<'r> fn(&'r Request<'_>, Data) -> std::pin::Pin<Box<dyn Future<Output = Outcome<'r>> + Send + 'r>>;
+pub type StaticHandler = for<'r> fn(&'r Request<'_>, Data) -> BoxFuture<'r, Outcome<'r>>;
 
 /// Information generated by the `route` attribute during codegen.
 pub struct StaticRouteInfo {

core/lib/src/data/from_data.rs

@@ -1,7 +1,6 @@
 use std::borrow::Borrow;
-use std::pin::Pin;
 
-use futures::future::{ready, Future, FutureExt};
+use futures::future::{ready, FutureExt, BoxFuture};
 use futures::io::AsyncReadExt;
 
 use crate::outcome::{self, IntoOutcome};
@@ -112,8 +111,8 @@ pub type Transformed<'a, T> =
         Outcome<&'a <T as FromData<'a>>::Borrowed, <T as FromData<'a>>::Error>
     >;
 
-pub type TransformFuture<'a, T, E> = Pin<Box<dyn Future<Output = Transform<Outcome<T, E>>> + Send + 'a>>;
+pub type TransformFuture<'a, T, E> = BoxFuture<'a, Transform<Outcome<T, E>>>;
-pub type FromDataFuture<'a, T, E> = Pin<Box<dyn Future<Output = Outcome<T, E>> + Send + 'a>>;
+pub type FromDataFuture<'a, T, E> = BoxFuture<'a, Outcome<T, E>>;
 
 /// Trait implemented by data guards to derive a value from request body data.
 ///

core/lib/src/ext.rs

@@ -2,7 +2,7 @@ use std::io;
 use std::pin::Pin;
 
 use futures::io::{AsyncRead, AsyncReadExt as _};
-use futures::future::{Future};
+use futures::future::BoxFuture;
 use futures::stream::Stream;
 use futures::task::{Poll, Context};
 
@@ -73,7 +73,7 @@ pub trait AsyncReadExt: AsyncRead {
     }
 
     // TODO.async: Verify correctness of this implementation.
-    fn read_max<'a>(&'a mut self, mut buf: &'a mut [u8]) -> Pin<Box<dyn Future<Output=io::Result<usize>> + Send + '_>>
+    fn read_max<'a>(&'a mut self, mut buf: &'a mut [u8]) -> BoxFuture<'_, io::Result<usize>>
         where Self: Send + Unpin
     {
         Box::pin(async move {

core/lib/src/fairing/ad_hoc.rs

@@ -1,7 +1,7 @@
-use std::future::Future;
-use std::pin::Pin;
 use std::sync::Mutex;
 
+use futures::future::BoxFuture;
+
 use crate::{Rocket, Request, Response, Data};
 use crate::fairing::{Fairing, Kind, Info};
 
@@ -51,7 +51,7 @@ enum AdHocKind {
     Request(Box<dyn Fn(&mut Request<'_>, &Data) + Send + Sync + 'static>),
     /// An ad-hoc **response** fairing. Called when a response is ready to be
     /// sent to a client.
-    Response(Box<dyn for<'a, 'r> Fn(&'a Request<'r>, &'a mut Response<'r>) -> Pin<Box<dyn Future<Output=()> + Send + 'a>> + Send + Sync + 'static>),
+    Response(Box<dyn for<'a, 'r> Fn(&'a Request<'r>, &'a mut Response<'r>) -> BoxFuture<'a, ()> + Send + Sync + 'static>),
 }
 
 impl AdHoc {
@@ -128,7 +128,7 @@ impl AdHoc {
     /// });
     /// ```
     pub fn on_response<F>(name: &'static str, f: F) -> AdHoc
-        where F: for<'a, 'r> Fn(&'a Request<'r>, &'a mut Response<'r>) -> Pin<Box<dyn Future<Output=()> + Send + 'a>> + Send + Sync + 'static
+        where F: for<'a, 'r> Fn(&'a Request<'r>, &'a mut Response<'r>) -> BoxFuture<'a, ()> + Send + Sync + 'static
     {
         AdHoc { name, kind: AdHocKind::Response(Box::new(f)) }
     }
@@ -170,7 +170,7 @@ impl Fairing for AdHoc {
         }
     }
 
-    fn on_response<'a, 'r>(&'a self, request: &'a Request<'r>, response: &'a mut Response<'r>) -> Pin<Box<dyn Future<Output=()> + Send + 'a>> {
+    fn on_response<'a, 'r>(&'a self, request: &'a Request<'r>, response: &'a mut Response<'r>) -> BoxFuture<'a, ()> {
         if let AdHocKind::Response(ref callback) = self.kind {
             callback(request, response)
         } else {

core/lib/src/fairing/mod.rs

@@ -47,8 +47,7 @@
 //! of other `Fairings` are not jeopardized. For instance, unless it is made
 //! abundantly clear, a fairing should not rewrite every request.
 
-use std::pin::Pin;
+use futures::future::BoxFuture;
-use std::future::Future;
 
 use crate::{Rocket, Request, Response, Data};
 
@@ -419,7 +418,7 @@ pub trait Fairing: Send + Sync + 'static {
     ///
     /// The default implementation of this method does nothing.
     #[allow(unused_variables)]
-    fn on_response<'a, 'r>(&'a self, request: &'a Request<'r>, response: &'a mut Response<'r>) -> Pin<Box<dyn Future<Output=()> + Send + 'a>> {
+    fn on_response<'a, 'r>(&'a self, request: &'a Request<'r>, response: &'a mut Response<'r>) -> BoxFuture<'a, ()> {
         Box::pin(async { })
     }
 }
@@ -446,7 +445,7 @@ impl<T: Fairing> Fairing for std::sync::Arc<T> {
     }
 
     #[inline]
-    fn on_response<'a, 'r>(&'a self, request: &'a Request<'r>, response: &'a mut Response<'r>) -> Pin<Box<dyn Future<Output=()> + Send + 'a>> {
+    fn on_response<'a, 'r>(&'a self, request: &'a Request<'r>, response: &'a mut Response<'r>) -> BoxFuture<'a, ()> {
         (self as &T).on_response(request, response)
     }
 }

core/lib/src/handler.rs

@@ -1,6 +1,6 @@
 //! Types and traits for request and error handlers and their return values.
 
-use futures::future::Future;
+use futures::future::BoxFuture;
 
 use crate::data::Data;
 use crate::request::Request;
@@ -12,7 +12,7 @@ use crate::outcome;
 pub type Outcome<'r> = outcome::Outcome<Response<'r>, Status, Data>;
 
 /// Type alias for the unwieldy `Handler` return type
-pub type HandlerFuture<'r> = std::pin::Pin<Box<dyn Future<Output = Outcome<'r>> + Send + 'r>>;
+pub type HandlerFuture<'r> = BoxFuture<'r, Outcome<'r>>;
 
 /// Trait implemented by types that can handle requests.
 ///
@@ -186,7 +186,7 @@ impl<F: Clone + Sync + Send + 'static> Handler for F
 /// The type of an error handler.
 pub type ErrorHandler = for<'r> fn(&'r Request<'_>) -> ErrorHandlerFuture<'r>;
 
-pub type ErrorHandlerFuture<'r> = std::pin::Pin<Box<dyn Future<Output = response::Result<'r>> + Send + 'r>>;
+pub type ErrorHandlerFuture<'r> = BoxFuture<'r, response::Result<'r>>;
 
 impl<'r> Outcome<'r> {
     /// Return the `Outcome` of response to `req` from `responder`.

core/lib/src/response/mod.rs

@@ -49,4 +49,4 @@ pub use self::debug::Debug;
 /// Type alias for the `Result` of a `Responder::respond` call.
 pub type Result<'r> = std::result::Result<self::Response<'r>, crate::http::Status>;
 /// Type alias for the `Result` of a `Responder::respond` call.
-pub type ResultFuture<'r> = std::pin::Pin<Box<dyn std::future::Future<Output=Result<'r>> + Send + 'r>>;
+pub type ResultFuture<'r> = futures::future::BoxFuture<'r, Result<'r>>;

core/lib/src/rocket.rs

@@ -6,9 +6,8 @@ use std::mem;
 use std::net::ToSocketAddrs;
 use std::sync::Arc;
 use std::time::Duration;
-use std::pin::Pin;
 
-use futures::future::{Future, FutureExt, TryFutureExt};
+use futures::future::{Future, FutureExt, TryFutureExt, BoxFuture};
 use futures::stream::StreamExt;
 use futures::task::SpawnExt;
 use futures_tokio_compat::Compat as TokioCompat;
@@ -256,7 +255,7 @@ impl Rocket {
                         request._set_method(Method::Get);
 
                         // Return early so we don't set cookies twice.
-                        let try_next: Pin<Box<dyn Future<Output = _> + Send>> = Box::pin(self.route_and_process(request, data));
+                        let try_next: BoxFuture<'_, _> = Box::pin(self.route_and_process(request, data));
                         return try_next.await;
                     } else {
                         // No match was found and it can't be autohandled. 404.

core/lib/src/router/mod.rs

@@ -3,7 +3,7 @@ mod route;
 
 use std::collections::hash_map::HashMap;
 
-use futures::future::Future;
+use futures::future::BoxFuture;
 
 pub use self::route::Route;
 
@@ -14,7 +14,7 @@ use crate::http::Method;
 type Selector = Method;
 
 // A handler to use when one is needed temporarily.
-pub(crate) fn dummy_handler<'r>(r: &'r Request<'_>, _: crate::Data) -> std::pin::Pin<Box<dyn Future<Output = crate::handler::Outcome<'r>> + Send + 'r>> {
+pub(crate) fn dummy_handler<'r>(r: &'r Request<'_>, _: crate::Data) -> BoxFuture<'r, crate::handler::Outcome<'r>> {
     crate::Outcome::from(r, ())
 }