Network sync refactoring (part 1) (#11303)

* Remove unnecessary imports, move one internal re-export into where it is actually used, make one import explicit

* Move a few data structures down into modules

* Use generic parameters in `sc-network` instead of `chain::Client` trait

* Remove unnecessary bound

substrate/client/network/src/protocol.rs

@@ -17,7 +17,6 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::{
-	chain::Client,
 	config::{self, ProtocolId, WarpSyncProvider},
 	error,
 	request_responses::RequestFailure,
@@ -49,6 +48,7 @@ use message::{
 use notifications::{Notifications, NotificationsOut};
 use prometheus_endpoint::{register, Gauge, GaugeVec, Opts, PrometheusError, Registry, U64};
 use prost::Message as _;
+use sc_client_api::{BlockBackend, HeaderBackend, ProofProvider};
 use sc_consensus::import_queue::{BlockImportError, BlockImportStatus, IncomingBlock, Origin};
 use sp_arithmetic::traits::SaturatedConversion;
 use sp_consensus::{block_validation::BlockAnnounceValidator, BlockOrigin};
@@ -76,6 +76,7 @@ pub mod message;
 pub mod sync;
 
 pub use notifications::{NotificationsSink, NotifsHandlerError, Ready};
+use sp_blockchain::HeaderMetadata;
 
 /// Interval at which we perform time based maintenance
 const TICK_TIMEOUT: time::Duration = time::Duration::from_millis(1100);
@@ -158,7 +159,7 @@ impl Metrics {
 }
 
 // Lock must always be taken in order declared here.
-pub struct Protocol<B: BlockT> {
+pub struct Protocol<B: BlockT, Client> {
 	/// Interval at which we call `tick`.
 	tick_timeout: Pin<Box<dyn Stream<Item = ()> + Send>>,
 	/// Pending list of messages to return from `poll` as a priority.
@@ -167,10 +168,10 @@ pub struct Protocol<B: BlockT> {
 	genesis_hash: B::Hash,
 	/// State machine that handles the list of in-progress requests. Only full node peers are
 	/// registered.
-	sync: ChainSync<B>,
+	sync: ChainSync<B, Client>,
 	// All connected peers. Contains both full and light node peers.
 	peers: HashMap<PeerId, Peer<B>>,
-	chain: Arc<dyn Client<B>>,
+	chain: Arc<Client>,
 	/// List of nodes for which we perform additional logging because they are important for the
 	/// user.
 	important_peers: HashSet<PeerId>,
@@ -283,18 +284,28 @@ impl<B: BlockT> BlockAnnouncesHandshake<B> {
 	}
 }
 
-impl<B: BlockT> Protocol<B> {
+impl<B, Client> Protocol<B, Client>
+where
+	B: BlockT,
+	Client: HeaderBackend<B>
+		+ BlockBackend<B>
+		+ HeaderMetadata<B, Error = sp_blockchain::Error>
+		+ ProofProvider<B>
+		+ Send
+		+ Sync
+		+ 'static,
+{
 	/// Create a new instance.
 	pub fn new(
 		config: ProtocolConfig,
-		chain: Arc<dyn Client<B>>,
+		chain: Arc<Client>,
 		protocol_id: ProtocolId,
 		network_config: &config::NetworkConfiguration,
 		notifications_protocols_handshakes: Vec<Vec<u8>>,
 		block_announce_validator: Box<dyn BlockAnnounceValidator<B> + Send>,
 		metrics_registry: Option<&Registry>,
 		warp_sync_provider: Option<Arc<dyn WarpSyncProvider<B>>>,
-	) -> error::Result<(Protocol<B>, sc_peerset::PeersetHandle, Vec<(PeerId, Multiaddr)>)> {
+	) -> error::Result<(Protocol<B, Client>, sc_peerset::PeersetHandle, Vec<(PeerId, Multiaddr)>)> {
 		let info = chain.info();
 		let sync = ChainSync::new(
 			config.sync_mode(),
@@ -1366,7 +1377,17 @@ pub enum CustomMessageOutcome<B: BlockT> {
 	None,
 }
 
-impl<B: BlockT> NetworkBehaviour for Protocol<B> {
+impl<B, Client> NetworkBehaviour for Protocol<B, Client>
+where
+	B: BlockT,
+	Client: HeaderBackend<B>
+		+ BlockBackend<B>
+		+ HeaderMetadata<B, Error = sp_blockchain::Error>
+		+ ProofProvider<B>
+		+ Send
+		+ Sync
+		+ 'static,
+{
 	type ConnectionHandler = <Notifications as NetworkBehaviour>::ConnectionHandler;
 	type OutEvent = CustomMessageOutcome<B>;