Remove the concept of individual `Transport::Listener` streams from `Transport`.
Instead the `Transport` is polled directly via `Transport::poll`. The
`Transport` is now responsible for driving its listeners.
This commit removes the `Clone` implementation on `GenTcpConfig` and consequently the `Clone`
implementations on `GenDnsConfig` and `WsConfig`.
When port-reuse is enabled, `GenTcpConfig` tracks the addresses it is listening in a `HashSet`. This
`HashSet` is shared with the `TcpListenStream`s via an `Arc<Mutex<_>>`. Given that `Clone` is
`derive`d on `GenTcpConfig`, cloning a `GenTcpConfig`, results in both instances sharing the same
set of listen addresses. This is not intuitive.
This behavior is for example error prone in the scenario where one wants to speak both plain DNS/TCP and
Websockets. Say a user creates the transport in the following way:
``` Rust
let transport = {
let tcp = tcp::TcpConfig::new().nodelay(true).port_reuse(true);
let dns_tcp = dns::DnsConfig::system(tcp).await?;
let ws_dns_tcp = websocket::WsConfig::new(dns_tcp.clone());
dns_tcp.or_transport(ws_dns_tcp)
};
```
Both `dns_tcp` and `ws_dns_tcp` share the set of listen addresses, given the `dns_tcp.clone()` to
create the `ws_dns_tcp`. Thus, with port-reuse, a Websocket dial might reuse a DNS/TCP listening
port instead of a Websocket listening port.
With this commit a user is forced to do the below, preventing the above error:
``` Rust
let transport = {
let dns_tcp = dns::DnsConfig::system(tcp::TcpConfig::new().nodelay(true).port_reuse(true)).await?;
let ws_dns_tcp = websocket::WsConfig::new(
dns::DnsConfig::system(tcp::TcpConfig::new().nodelay(true).port_reuse(true)).await?,
);
dns_tcp.or_transport(ws_dns_tcp)
};
```
Co-authored-by: Thomas Eizinger <thomas@eizinger.io>
Previously `libp2p-swarm` required a `Transport` to be `Clone`. Methods
on `Transport`, e.g. `Transport::dial` would take ownership, requiring
e.g. a `Clone::clone` before calling `Transport::dial`.
The requirement of `Transport` to be `Clone` is no longer needed in
`libp2p-swarm`. E.g. concurrent dialing can be done without a clone per
dial.
This commit removes the requirement of `Clone` for `Transport` in
`libp2p-swarm`. As a follow-up methods on `Transport` no longer take
ownership, but instead a mutable reference (`&mut self`).
On the one hand this simplifies `libp2p-swarm`, on the other it
simplifies implementations of `Transport`.
Move transport upgrade protocols from `protocols/`
to `transports/`, such that only "application protocols"
that depend on `libp2p-swarm` remain in `protocols/`,
whereas there is no such dependency in `transports/`
outside of integration tests.
Tweak README and top-level CHANGELOG.
