Remove BoxFuture from core and replace with manual future impl

Author: faern

core/src/lib.rs

@@ -57,6 +57,7 @@
 
 #[macro_use]
 extern crate error_chain;
+#[macro_use]
 extern crate futures;
 extern crate jsonrpc_core;
 #[macro_use]
@@ -65,6 +66,7 @@ extern crate serde;
 #[cfg_attr(test, macro_use)]
 extern crate serde_json;
 
+use futures::Async;
 use futures::future::Future;
 use jsonrpc_core::types::{Id, MethodCall, Params, Version};
 use serde_json::Value as JsonValue;
@@ -102,34 +104,94 @@ error_chain! {
     }
 }
 
-/// A `Future` trait object.
-pub type BoxFuture<T, E> = Box<Future<Item = T, Error = E> + Send>;
 
 /// A lazy RPC call `Future`. The actual call has not been sent when an instance of this type
 /// is returned from a client generated by the macro in this crate. This is a `Future` that, when
 /// executed, performs the RPC call.
-pub struct RpcRequest<T>(BoxFuture<T, Error>);
+pub struct RpcRequest<T, F>(::std::result::Result<InnerRpcRequest<T, F>, Option<Error>>);
 
-impl<T> RpcRequest<T> {
+impl<T, E, F> RpcRequest<T, F>
+where
+    T: serde::de::DeserializeOwned + Send + 'static,
+    E: ::std::error::Error + Send + 'static,
+    F: Future<Item = Vec<u8>, Error = E> + Send + 'static,
+{
     /// Consume this RPC request and run it synchronously. This blocks until the RPC call is done,
     /// then the result of the call is returned.
     pub fn call(self) -> Result<T> {
-        self.0.wait()
+        self.wait()
     }
 }
 
-impl<T> Future for RpcRequest<T> {
+impl<T, E, F> Future for RpcRequest<T, F>
+where
+    T: serde::de::DeserializeOwned + Send + 'static,
+    E: ::std::error::Error + Send + 'static,
+    F: Future<Item = Vec<u8>, Error = E> + Send + 'static,
+{
     type Item = T;
     type Error = Error;
 
     fn poll(&mut self) -> futures::Poll<Self::Item, Self::Error> {
-        self.0.poll()
+        match self.0 {
+            Ok(ref mut inner) => inner.poll(),
+            Err(ref mut error_option) => Err(error_option
+                .take()
+                .expect("Cannot call RpcRequest poll twice when in error state")),
+        }
     }
 }
 
+struct InnerRpcRequest<T, F> {
+    transport_future: F,
+    method: String,
+    id: Id,
+    _marker: ::std::marker::PhantomData<T>,
+}
+
+impl<T, F> InnerRpcRequest<T, F> {
+    fn new(transport_future: F, method: String, id: Id) -> Self {
+        Self {
+            transport_future,
+            method,
+            id,
+            _marker: ::std::marker::PhantomData,
+        }
+    }
+}
+
+impl<T, E, F> Future for InnerRpcRequest<T, F>
+where
+    T: serde::de::DeserializeOwned + Send + 'static,
+    E: ::std::error::Error + Send + 'static,
+    F: Future<Item = Vec<u8>, Error = E> + Send + 'static,
+{
+    type Item = T;
+    type Error = Error;
+
+    fn poll(&mut self) -> futures::Poll<Self::Item, Self::Error> {
+        let response_raw = try_ready!(
+            self.transport_future
+                .poll()
+                .chain_err(|| ErrorKind::TransportError)
+        );
+        trace!(
+            "Deserializing {} byte response to method \"{}\" with id {:?}",
+            response_raw.len(),
+            self.method,
+            self.id
+        );
+        response::parse(&response_raw, &self.id).map(|t| Async::Ready(t))
+    }
+}
+
+
 /// Trait for types acting as a transport layer for the JSON-RPC 2.0 clients generated by the
 /// `jsonrpc_client` macro.
 pub trait Transport {
+    /// The future type this transport returns on send operations.
+    type Future: Future<Item = Vec<u8>, Error = Self::Error> + Send + 'static;
+
     /// The type of error that this transport emits if it fails.
     type Error: ::std::error::Error + Send + 'static;
 
@@ -139,7 +201,7 @@ pub trait Transport {
 
     /// Sends the given data over the transport and returns a future that will complete with the
     /// response to the request, or the transport specific error if something went wrong.
-    fn send(&self, json_data: Vec<u8>) -> BoxFuture<Vec<u8>, Self::Error>;
+    fn send(&self, json_data: Vec<u8>) -> Self::Future;
 }
 
 
@@ -150,41 +212,25 @@ pub trait Transport {
 /// # Not intended for direct use
 /// This is being called from the client structs generated by the `jsonrpc_client` macro. This
 /// function is not intended to be used directly, only the generated structs should call this.
-pub fn call_method<T, P, R>(transport: &mut T, method: String, params: P) -> RpcRequest<R>
+pub fn call_method<T, P, R>(
+    transport: &mut T,
+    method: String,
+    params: P,
+) -> RpcRequest<R, T::Future>
 where
     T: Transport,
     P: serde::Serialize,
     R: serde::de::DeserializeOwned + Send + 'static,
 {
-    let raw_id = transport.get_next_id();
-    let id = Id::Num(raw_id);
-    trace!(
-        "Serializing call to method \"{}\" with id {}",
-        method,
-        raw_id
-    );
+    let id = Id::Num(transport.get_next_id());
+    trace!("Serializing call to method \"{}\" with id {:?}", method, id);
     let request_serialization_result = serialize_request(id.clone(), method.clone(), params)
         .chain_err(|| ErrorKind::SerializeError);
     match request_serialization_result {
-        Err(e) => RpcRequest(Box::new(futures::future::err(e))),
+        Err(e) => RpcRequest(Err(Some(e))),
         Ok(request_raw) => {
-            trace!(
-                "Sending call to method \"{}\" with id {} to transport",
-                method,
-                raw_id
-            );
-            let future = transport
-                .send(request_raw)
-                .map_err(|e| Error::with_chain(e, ErrorKind::TransportError))
-                .and_then(move |response_raw: Vec<u8>| {
-                    trace!(
-                        "Deserializing response to method \"{}\" with id {}",
-                        method,
-                        raw_id
-                    );
-                    response::parse::<R>(&response_raw, id)
-                });
-            RpcRequest(Box::new(future))
+            let transport_future = transport.send(request_raw);
+            RpcRequest(Ok(InnerRpcRequest::new(transport_future, method, id)))
         }
     }
 }
@@ -220,19 +266,22 @@ mod tests {
     use super::*;
     use std::io;
 
+    pub type BoxFuture<T, E> = Box<Future<Item = T, Error = E> + Send>;
+
     /// A test transport that just echoes back a response containing the entire request as the
     /// result.
     #[derive(Clone)]
     struct EchoTransport;
 
     impl Transport for EchoTransport {
+        type Future = BoxFuture<Vec<u8>, io::Error>;
         type Error = io::Error;
 
         fn get_next_id(&mut self) -> u64 {
             1
         }
 
-        fn send(&self, json_data: Vec<u8>) -> BoxFuture<Vec<u8>, io::Error> {
+        fn send(&self, json_data: Vec<u8>) -> Self::Future {
             let json = json!({
                 "jsonrpc": "2.0",
                 "id": 1,
@@ -247,13 +296,14 @@ mod tests {
     struct ErrorTransport;
 
     impl Transport for ErrorTransport {
+        type Future = BoxFuture<Vec<u8>, io::Error>;
         type Error = io::Error;
 
         fn get_next_id(&mut self) -> u64 {
             1
         }
 
-        fn send(&self, _json_data: Vec<u8>) -> BoxFuture<Vec<u8>, io::Error> {
+        fn send(&self, _json_data: Vec<u8>) -> Self::Future {
             let json = json!({
                 "jsonrpc": "2.0",
                 "id": 1,

core/src/macros.rs

@@ -32,7 +32,7 @@ macro_rules! jsonrpc_client {
             $(
                 $(#[$doc])*
                 pub fn $method(&mut $selff $(, $arg_name: $arg_ty)*)
-                    -> $crate::RpcRequest<$return_ty>
+                    -> $crate::RpcRequest<$return_ty, T::Future>
                 {
                     let method = String::from(stringify!($method));
                     let params = expand_params!($($arg_name,)*);

core/src/response.rs

@@ -13,7 +13,7 @@ use serde_json;
 
 /// Parses a binary response into json, extracts the "result" field and tries to deserialize that
 /// to the desired type.
-pub fn parse<R>(response_raw: &[u8], expected_id: Id) -> Result<R>
+pub fn parse<R>(response_raw: &[u8], expected_id: &Id) -> Result<R>
 where
     R: serde::de::DeserializeOwned,
 {
@@ -24,7 +24,7 @@ where
         ErrorKind::ResponseError("Not JSON-RPC 2.0 compatible")
     );
     ensure!(
-        response.id() == &expected_id,
+        response.id() == expected_id,
         ErrorKind::ResponseError("Response id not equal to request id")
     );
     match response {
@@ -33,8 +33,6 @@ where
             serde_json::from_value::<R>(success.result)
                 .chain_err(|| ErrorKind::ResponseError("Not valid for target type"))
         }
-        Output::Failure(failure) => {
-            Err(ErrorKind::JsonRpcError(failure.error).into())
-        }
+        Output::Failure(failure) => Err(ErrorKind::JsonRpcError(failure.error).into()),
     }
 }

http/src/lib.rs

@@ -81,7 +81,7 @@ extern crate native_tls;
 use futures::{future, Future, Stream};
 use futures::sync::{mpsc, oneshot};
 use hyper::{Client, Request, StatusCode, Uri};
-use jsonrpc_client_core::{BoxFuture, Transport};
+use jsonrpc_client_core::Transport;
 use std::str::FromStr;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};
@@ -119,6 +119,9 @@ error_chain! {
 type CoreSender = mpsc::UnboundedSender<(Request, oneshot::Sender<Result<Vec<u8>>>)>;
 type CoreReceiver = mpsc::UnboundedReceiver<(Request, oneshot::Sender<Result<Vec<u8>>>)>;
 
+/// Future type returned from `HttpTransport`.
+pub type HttpFuture<T, E> = Box<Future<Item = T, Error = E> + Send>;
+
 /// The main struct of the HTTP transport implementation for
 /// [`jsonrpc_client_core`](../jsonrpc_client_core).
 ///
@@ -336,13 +339,14 @@ impl HttpHandle {
 }
 
 impl Transport for HttpHandle {
+    type Future = HttpFuture<Vec<u8>, Error>;
     type Error = Error;
 
     fn get_next_id(&mut self) -> u64 {
         self.id.fetch_add(1, Ordering::SeqCst) as u64
     }
 
-    fn send(&self, json_data: Vec<u8>) -> BoxFuture<Vec<u8>, Error> {
+    fn send(&self, json_data: Vec<u8>) -> Self::Future {
         let request = self.create_request(json_data.clone());
         let (response_tx, response_rx) = oneshot::channel();
         let future = future::result(self.request_tx.unbounded_send((request, response_tx)))