1 use crate::sealed::Sealed; 2 use std::future::Future; 3 use std::task::{Context, Poll}; 4 use tokio::io::{AsyncRead, AsyncWrite}; 5 use tower_service::Service; 6 7 /// The [`MakeConnection`] trait is used to create transports. 8 /// 9 /// The goal of this service is to allow composable methods for creating 10 /// `AsyncRead + AsyncWrite` transports. This could mean creating a TLS 11 /// based connection or using some other method to authenticate the connection. 12 pub trait MakeConnection<Target>: Sealed<(Target,)> { 13 /// The transport provided by this service 14 type Connection: AsyncRead + AsyncWrite; 15 16 /// Errors produced by the connecting service 17 type Error; 18 19 /// The future that eventually produces the transport 20 type Future: Future<Output = Result<Self::Connection, Self::Error>>; 21 22 /// Returns `Poll::Ready(Ok(()))` when it is able to make more connections. poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>23 fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>; 24 25 /// Connect and return a transport asynchronously make_connection(&mut self, target: Target) -> Self::Future26 fn make_connection(&mut self, target: Target) -> Self::Future; 27 } 28 29 impl<S, Target> Sealed<(Target,)> for S where S: Service<Target> {} 30 31 impl<C, Target> MakeConnection<Target> for C 32 where 33 C: Service<Target>, 34 C::Response: AsyncRead + AsyncWrite, 35 { 36 type Connection = C::Response; 37 type Error = C::Error; 38 type Future = C::Future; 39 poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>40 fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { 41 Service::poll_ready(self, cx) 42 } 43 make_connection(&mut self, target: Target) -> Self::Future44 fn make_connection(&mut self, target: Target) -> Self::Future { 45 Service::call(self, target) 46 } 47 } 48