refactor(request-response): revise public API to follow naming convention (#3159)

protocols/request-response/src/codec.rs

@@ -25,8 +25,12 @@ use futures::prelude::*;
 use std::io;
 
 /// A `RequestResponseCodec` defines the request and response types
-/// for a [`RequestResponse`](crate::RequestResponse) protocol or
+/// for a request-response `Behaviour` protocol or
 /// protocol family and how they are encoded / decoded on an I/O stream.
+#[deprecated(
+    since = "0.24.0",
+    note = "Use re-exports that omit `RequestResponse` prefix, i.e. `libp2p::request_response::Codec`"
+)]
 #[async_trait]
 pub trait RequestResponseCodec {
     /// The type of protocol(s) or protocol versions being negotiated.
@@ -78,3 +82,118 @@ pub trait RequestResponseCodec {
     where
         T: AsyncWrite + Unpin + Send;
 }
+
+/// A `Codec` defines the request and response types
+/// for a request-response [`Behaviour`](crate::Behaviour) protocol or
+/// protocol family and how they are encoded / decoded on an I/O stream.
+#[async_trait]
+pub trait Codec {
+    /// The type of protocol(s) or protocol versions being negotiated.
+    type Protocol: ProtocolName + Send + Clone;
+    /// The type of inbound and outbound requests.
+    type Request: Send;
+    /// The type of inbound and outbound responses.
+    type Response: Send;
+
+    /// Reads a request from the given I/O stream according to the
+    /// negotiated protocol.
+    async fn read_request<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+    ) -> io::Result<Self::Request>
+    where
+        T: AsyncRead + Unpin + Send;
+
+    /// Reads a response from the given I/O stream according to the
+    /// negotiated protocol.
+    async fn read_response<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+    ) -> io::Result<Self::Response>
+    where
+        T: AsyncRead + Unpin + Send;
+
+    /// Writes a request to the given I/O stream according to the
+    /// negotiated protocol.
+    async fn write_request<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+        req: Self::Request,
+    ) -> io::Result<()>
+    where
+        T: AsyncWrite + Unpin + Send;
+
+    /// Writes a response to the given I/O stream according to the
+    /// negotiated protocol.
+    async fn write_response<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+        res: Self::Response,
+    ) -> io::Result<()>
+    where
+        T: AsyncWrite + Unpin + Send;
+}
+
+#[allow(deprecated)]
+#[async_trait]
+impl<U> Codec for U
+where
+    U: RequestResponseCodec + Send,
+    U::Protocol: Sync,
+{
+    type Protocol = U::Protocol;
+
+    type Request = U::Request;
+
+    type Response = U::Response;
+
+    async fn read_request<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+    ) -> io::Result<Self::Request>
+    where
+        T: AsyncRead + Unpin + Send,
+    {
+        self.read_request(protocol, io).await
+    }
+
+    async fn read_response<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+    ) -> io::Result<Self::Response>
+    where
+        T: AsyncRead + Unpin + Send,
+    {
+        self.read_response(protocol, io).await
+    }
+
+    async fn write_request<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+        req: Self::Request,
+    ) -> io::Result<()>
+    where
+        T: AsyncWrite + Unpin + Send,
+    {
+        self.write_request(protocol, io, req).await
+    }
+
+    async fn write_response<T>(
+        &mut self,
+        protocol: &Self::Protocol,
+        io: &mut T,
+        res: Self::Response,
+    ) -> io::Result<()>
+    where
+        T: AsyncWrite + Unpin + Send,
+    {
+        self.write_response(protocol, io, res).await
+    }
+}