limit number of pending messages at outbound lane (#715)

bridges/modules/message-lane/src/lib.rs

@@ -293,10 +293,12 @@ decl_module! {
 				})?;
 
 			// now let's enforce any additional lane rules
+			let mut lane = outbound_lane::<T, I>(lane_id);
 			T::LaneMessageVerifier::verify_message(
 				&submitter,
 				&delivery_and_dispatch_fee,
 				&lane_id,
+				&lane.data(),
 				&payload,
 			).map_err(|err| {
 				frame_support::debug::trace!(
@@ -326,7 +328,6 @@ decl_module! {
 			})?;
 
 			// finally, save message in outbound storage and emit event
-			let mut lane = outbound_lane::<T, I>(lane_id);
 			let encoded_payload = payload.encode();
 			let encoded_payload_len = encoded_payload.len();
 			let nonce = lane.send_message(MessageData {

bridges/modules/message-lane/src/mock.rs

@@ -21,7 +21,7 @@ use bp_message_lane::{
 		LaneMessageVerifier, MessageDeliveryAndDispatchPayment, RelayersRewards, Sender, TargetHeaderChain,
 	},
 	target_chain::{DispatchMessage, MessageDispatch, ProvedLaneMessages, ProvedMessages, SourceHeaderChain},
-	InboundLaneData, LaneId, Message, MessageData, MessageKey, MessageNonce,
+	InboundLaneData, LaneId, Message, MessageData, MessageKey, MessageNonce, OutboundLaneData,
 };
 use bp_runtime::Size;
 use codec::{Decode, Encode};
@@ -253,6 +253,7 @@ impl LaneMessageVerifier<AccountId, TestPayload, TestMessageFee> for TestLaneMes
 		_submitter: &Sender<AccountId>,
 		delivery_and_dispatch_fee: &TestMessageFee,
 		_lane: &LaneId,
+		_lane_outbound_data: &OutboundLaneData,
 		_payload: &TestPayload,
 	) -> Result<(), Self::Error> {
 		if *delivery_and_dispatch_fee != 0 {

bridges/modules/message-lane/src/outbound_lane.rs

@@ -49,6 +49,11 @@ impl<S: OutboundLaneStorage> OutboundLane<S> {
 		OutboundLane { storage }
 	}
 
+	/// Get this lane data.
+	pub fn data(&self) -> OutboundLaneData {
+		self.storage.data()
+	}
+
 	/// Send message over lane.
 	///
 	/// Returns new message nonce.