Move legacy_proto to protocol (#4296)

* Move legacy_proto to protocol

* Edition 2018ize legacy_proto

* Some basic documentation

substrate/client/network/src/lib.rs

@@ -170,7 +170,6 @@
 
 mod behaviour;
 mod chain;
-mod legacy_proto;
 mod debug_info;
 mod discovery;
 mod on_demand_layer;

substrate/client/network/src/protocol.rs

@@ -15,7 +15,7 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 use crate::{DiscoveryNetBehaviour, config::ProtocolId};
-use crate::legacy_proto::{LegacyProto, LegacyProtoOut};
+use legacy_proto::{LegacyProto, LegacyProtoOut};
 use crate::utils::interval;
 use bytes::BytesMut;
 use futures::prelude::*;
@@ -55,7 +55,9 @@ use client_api::{FetchChecker, ChangesProof, StorageProof};
 use crate::error;
 use util::LruHashSet;
 
+mod legacy_proto;
 mod util;
+
 pub mod consensus_gossip;
 pub mod message;
 pub mod event;

substrate/client/network/src/protocol/legacy_proto.rs

@@ -14,6 +14,12 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
+//! Implementation of libp2p's `NetworkBehaviour` trait that opens a single substream with the
+//! remote and then allows any communication with them.
+//!
+//! The `Protocol` struct uses `LegacyProto` in order to open substreams with the rest of the
+//! network, then performs the Substrate protocol handling on top.
+
 pub use self::behaviour::{LegacyProto, LegacyProtoOut};
 
 mod behaviour;

substrate/client/network/src/protocol/legacy_proto/behaviour.rs

@@ -15,8 +15,8 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 use crate::{DiscoveryNetBehaviour, config::ProtocolId};
-use crate::legacy_proto::handler::{CustomProtoHandlerProto, CustomProtoHandlerOut, CustomProtoHandlerIn};
-use crate::legacy_proto::upgrade::RegisteredProtocol;
+use crate::protocol::legacy_proto::handler::{CustomProtoHandlerProto, CustomProtoHandlerOut, CustomProtoHandlerIn};
+use crate::protocol::legacy_proto::upgrade::RegisteredProtocol;
 use bytes::BytesMut;
 use fnv::FnvHashMap;
 use futures::prelude::*;

substrate/client/network/src/protocol/legacy_proto/handler.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use crate::legacy_proto::upgrade::{RegisteredProtocol, RegisteredProtocolEvent, RegisteredProtocolSubstream};
+use super::upgrade::{RegisteredProtocol, RegisteredProtocolEvent, RegisteredProtocolSubstream};
 use bytes::BytesMut;
 use futures::prelude::*;
 use futures03::{compat::Compat, TryFutureExt as _};

substrate/client/network/src/protocol/legacy_proto/tests.rs

@@ -26,7 +26,7 @@ use libp2p::{PeerId, Multiaddr, Transport};
 use rand::seq::SliceRandom;
 use std::{io, time::Duration, time::Instant};
 use crate::message::Message;
-use crate::legacy_proto::{LegacyProto, LegacyProtoOut};
+use crate::protocol::legacy_proto::{LegacyProto, LegacyProtoOut};
 use test_client::runtime::Block;
 
 /// Builds two nodes that have each other as bootstrap nodes.