rust-libp2p/protocols/request-response/src/codec.rs

// Copyright 2020 Parity Technologies (UK) Ltd.
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pub use libp2p_core::ProtocolName;

use async_trait::async_trait;
use futures::prelude::*;
use std::io;

/// A `RequestResponseCodec` defines the request and response types
/// 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.
    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;
}

/// 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
    }
}