Availability store subsystem (#1404)

* Initial commit

* WIP

* Make atomic transactions

* Remove pruning code

* Fix build and add a Nop to bridge

* Fixes from review

* Move config struct around for clarity

* Rename constructor and warn on missing docs

* Fix a test and rename a message

* Fix some more reviews

* Obviously failed to rebase cleanly

polkadot/node/network/bitfield-distribution/src/lib.rs

@@ -179,6 +179,9 @@ impl BitfieldDistribution {
 						// defer the cleanup to the view change
 					}
 				}
+				FromOverseer::Signal(OverseerSignal::BlockFinalized(hash)) => {
+					trace!(target: "bitd", "Block finalized {:?}", hash);
+				}
 				FromOverseer::Signal(OverseerSignal::Conclude) => {
 					trace!(target: "bitd", "Conclude");
 					return Ok(());

polkadot/node/network/bridge/src/lib.rs

@@ -213,6 +213,7 @@ enum Action {
 	PeerMessages(PeerId, Vec<WireMessage>),
 
 	Abort,
+	Nop,
 }
 
 fn action_from_overseer_message(
@@ -229,6 +230,8 @@ fn action_from_overseer_message(
 			NetworkBridgeMessage::SendMessage(peers, protocol, message)
 				=> Action::SendMessage(peers, protocol, message),
 		},
+		Ok(FromOverseer::Signal(OverseerSignal::BlockFinalized(_)))
+			=> Action::Nop,
 		Err(e) => {
 			log::warn!(target: TARGET, "Shutting down Network Bridge due to error {:?}", e);
 			Action::Abort
@@ -502,6 +505,7 @@ async fn run_network<N: Network>(
 			},
 
 			Action::Abort => return Ok(()),
+			Action::Nop => (),
 		}
 	}
 }

polkadot/node/network/pov-distribution/src/lib.rs

@@ -128,6 +128,7 @@ async fn handle_signal(
 
 			Ok(false)
 		}
+		OverseerSignal::BlockFinalized(_) => Ok(false),
 	}
 }
 

polkadot/node/network/statement-distribution/src/lib.rs

@@ -864,6 +864,9 @@ async fn run(
 						.or_insert(ActiveHeadData::new(validators, session_index));
 				}
 			}
+			FromOverseer::Signal(OverseerSignal::BlockFinalized(_block_hash)) => {
+				// do nothing
+			}
 			FromOverseer::Signal(OverseerSignal::Conclude) => break,
 			FromOverseer::Communication { msg } => match msg {
 				StatementDistributionMessage::Share(relay_parent, statement) =>