chainntnfs/btcdnotify: remove old spend notification handling logic

In this commit, we remove the old spend notification logic within the
BtcdNotifier as it's been phased out by the TxNotifier.

chainntnfs/btcdnotify/btcd.go

@@ -74,8 +74,6 @@ type BtcdNotifier struct {
 	notificationCancels  chan interface{}
 	notificationRegistry chan interface{}
 
-	spendNotifications map[wire.OutPoint]map[uint64]*spendNotification
-
 	txNotifier *chainntnfs.TxNotifier
 
 	blockEpochClients map[uint64]*blockEpochRegistration
@@ -114,8 +112,6 @@ func New(config *rpcclient.ConnConfig, spendHintCache chainntnfs.SpendHintCache,
 
 		blockEpochClients: make(map[uint64]*blockEpochRegistration),
 
-		spendNotifications: make(map[wire.OutPoint]map[uint64]*spendNotification),
-
 		chainUpdates: queue.NewConcurrentQueue(10),
 		txUpdates:    queue.NewConcurrentQueue(10),
 
@@ -204,11 +200,6 @@ func (b *BtcdNotifier) Stop() error {
 
 	// Notify all pending clients of our shutdown by closing the related
 	// notification channels.
-	for _, spendClients := range b.spendNotifications {
-		for _, spendClient := range spendClients {
-			close(spendClient.spendChan)
-		}
-	}
 	for _, epochClient := range b.blockEpochClients {
 		close(epochClient.cancelChan)
 		epochClient.wg.Wait()
@@ -276,19 +267,6 @@ out:
 		select {
 		case cancelMsg := <-b.notificationCancels:
 			switch msg := cancelMsg.(type) {
-			case *spendCancel:
-				chainntnfs.Log.Infof("Cancelling spend "+
-					"notification for out_point=%v, "+
-					"spend_id=%v", msg.op, msg.spendID)
-
-				// Before we attempt to close the spendChan,
-				// ensure that the notification hasn't already
-				// yet been dispatched.
-				if outPointClients, ok := b.spendNotifications[msg.op]; ok {
-					close(outPointClients[msg.spendID].spendChan)
-					delete(b.spendNotifications[msg.op], msg.spendID)
-				}
-
 			case *epochCancel:
 				chainntnfs.Log.Infof("Cancelling epoch "+
 					"notification, epoch_id=%v", msg.epochID)
@@ -315,16 +293,6 @@ out:
 			}
 		case registerMsg := <-b.notificationRegistry:
 			switch msg := registerMsg.(type) {
-			case *spendNotification:
-				chainntnfs.Log.Infof("New spend subscription: "+
-					"utxo=%v", msg.targetOutpoint)
-				op := *msg.targetOutpoint
-
-				if _, ok := b.spendNotifications[op]; !ok {
-					b.spendNotifications[op] = make(map[uint64]*spendNotification)
-				}
-				b.spendNotifications[op][msg.spendID] = msg
-
 			case *chainntnfs.HistoricalConfDispatch:
 				// Look up whether the transaction is already
 				// included in the active chain. We'll do this
@@ -713,28 +681,6 @@ func (b *BtcdNotifier) notifyBlockEpochClient(epochClient *blockEpochRegistratio
 	}
 }
 
-// spendNotification couples a target outpoint along with the channel used for
-// notifications once a spend of the outpoint has been detected.
-type spendNotification struct {
-	targetOutpoint *wire.OutPoint
-
-	spendChan chan *chainntnfs.SpendDetail
-
-	spendID uint64
-
-	heightHint uint32
-}
-
-// spendCancel is a message sent to the BtcdNotifier when a client wishes to
-// cancel an outstanding spend notification that has yet to be dispatched.
-type spendCancel struct {
-	// op is the target outpoint of the notification to be cancelled.
-	op wire.OutPoint
-
-	// spendID the ID of the notification to cancel.
-	spendID uint64
-}
-
 // RegisterSpendNtfn registers an intent to be notified once the target
 // outpoint has been spent by a transaction on-chain. Once a spend of the target
 // outpoint has been detected, the details of the spending event will be sent