chainntnfs/btcd: use HistoricalConfDispatch in ntfn registry

chainntnfs/btcdnotify/btcd.go

@@ -324,13 +324,7 @@ out:
 				}
 				b.spendNotifications[op][msg.spendID] = msg
 
-			case *chainntnfs.ConfNtfn:
+			case *chainntnfs.HistoricalConfDispatch:
-				chainntnfs.Log.Infof("New confirmation "+
-					"subscription: txid=%v, numconfs=%v",
-					msg.TxID, msg.NumConfirmations)
-
-				bestHeight := uint32(b.bestBlock.Height)
-
 				// Look up whether the transaction is already
 				// included in the active chain. We'll do this
 				// in a goroutine to prevent blocking
@@ -340,8 +334,7 @@ out:
 					defer b.wg.Done()
 
 					confDetails, _, err := b.historicalConfDetails(
-						msg.TxID, msg.HeightHint,
+						msg.TxID, msg.StartHeight, msg.EndHeight,
-						bestHeight,
 					)
 					if err != nil {
 						chainntnfs.Log.Error(err)
@@ -356,8 +349,7 @@ out:
 					// cache at tip, since any pending
 					// rescans have now completed.
 					err = b.txConfNotifier.UpdateConfDetails(
-						*msg.TxID, msg.ConfID,
+						*msg.TxID, confDetails,
-						confDetails,
 					)
 					if err != nil {
 						chainntnfs.Log.Error(err)
@@ -523,7 +515,7 @@ out:
 // historicalConfDetails looks up whether a transaction is already included in a
 // block in the active chain and, if so, returns details about the confirmation.
 func (b *BtcdNotifier) historicalConfDetails(txid *chainhash.Hash,
-	heightHint, currentHeight uint32) (*chainntnfs.TxConfirmation,
+	startHeight, endHeight uint32) (*chainntnfs.TxConfirmation,
 	chainntnfs.TxConfStatus, error) {
 
 	// We'll first attempt to retrieve the transaction using the node's
@@ -539,7 +531,7 @@ func (b *BtcdNotifier) historicalConfDetails(txid *chainhash.Hash,
 	case err != nil:
 		chainntnfs.Log.Debugf("Failed getting conf details from "+
 			"index (%v), scanning manually", err)
-		return b.confDetailsManually(txid, heightHint, currentHeight)
+		return b.confDetailsManually(txid, startHeight, endHeight)
 
 	// The transaction was found within the node's mempool.
 	case txStatus == chainntnfs.TxFoundMempool:
@@ -638,15 +630,15 @@ func (b *BtcdNotifier) confDetailsFromTxIndex(txid *chainhash.Hash,
 // earliest height the transaction could have been included in, to the current
 // height in the chain. If the transaction is found, its confirmation details
 // are returned. Otherwise, nil is returned.
-func (b *BtcdNotifier) confDetailsManually(txid *chainhash.Hash, heightHint,
+func (b *BtcdNotifier) confDetailsManually(txid *chainhash.Hash, startHeight,
-	currentHeight uint32) (*chainntnfs.TxConfirmation,
+	endHeight uint32) (*chainntnfs.TxConfirmation,
 	chainntnfs.TxConfStatus, error) {
 
 	targetTxidStr := txid.String()
 
 	// Begin scanning blocks at every height to determine where the
 	// transaction was included in.
-	for height := heightHint; height <= currentHeight; height++ {
+	for height := startHeight; height <= endHeight; height++ {
 		// Ensure we haven't been requested to shut down before
 		// processing the next height.
 		select {
@@ -1024,12 +1016,24 @@ func (b *BtcdNotifier) RegisterConfirmationsNtfn(txid *chainhash.Hash, _ []byte,
 		HeightHint:       heightHint,
 	}
 
-	if err := b.txConfNotifier.Register(ntfn); err != nil {
+	chainntnfs.Log.Infof("New confirmation subscription: "+
+		"txid=%v, numconfs=%v", txid, numConfs)
+
+	// Register the conf notification with txconfnotifier. A non-nil value
+	// for `dispatch` will be returned if we are required to perform a
+	// manual scan for the confirmation. Otherwise the notifier will begin
+	// watching at tip for the transaction to confirm.
+	dispatch, err := b.txConfNotifier.Register(ntfn)
+	if err != nil {
 		return nil, err
 	}
 
+	if dispatch == nil {
+		return ntfn.Event, nil
+	}
+
 	select {
-	case b.notificationRegistry <- ntfn:
+	case b.notificationRegistry <- dispatch:
 		return ntfn.Event, nil
 	case <-b.quit:
 		return nil, ErrChainNotifierShuttingDown