chainntfns: update BtcdNotifier to adhere to new ChainNotifier interface

* Re-orgs are still unhanded.

* RegisterSpendNtfn should perhaps also register directly with the rpc
client instead of pushing the responsibility to the caller.

chainntfs/btcdnotify/btcd.go

@@ -14,11 +14,16 @@ import (
 
 // BtcdNotifier...
 type BtcdNotifier struct {
+	started int32 // To be used atomically
+	stopped int32 // To be used atomically
+
 	// TODO(roasbeef): refactor to use the new NotificationServer
 	conn ChainConnection
 
 	notificationRegistry chan interface{}
 
+	// TODO(roasbeef): make map point to slices? Would allow for multiple
+	// clients to listen for same spend. Would we ever need this?
 	spendNotifications map[wire.OutPoint]*spendNotification
 	confNotifications  map[wire.ShaHash]*confirmationsNotification
 	confHeap           *confirmationHeap
@@ -29,16 +34,15 @@ type BtcdNotifier struct {
 
 	rpcConnected chan struct{}
 
-	wg      sync.WaitGroup
-	started int32 // To be used atomically
-	stopped int32 // To be used atomically
-	quit    chan struct{}
+	wg   sync.WaitGroup
+	quit chan struct{}
 }
 
 var _ chainntnfs.ChainNotifier = (*BtcdNotifier)(nil)
 
 // NewBtcdNotifier...
 func NewBtcdNotifier(c ChainConnection) (*BtcdNotifier, error) {
+	// TODO(roasbeef): take client also in order to get notifications?
 	return &BtcdNotifier{
 		conn:                 c,
 		notificationRegistry: make(chan interface{}),
@@ -95,7 +99,7 @@ out:
 		case registerMsg := <-b.notificationRegistry:
 			switch msg := registerMsg.(type) {
 			case *spendNotification:
-				b.spendNotifications[*msg.outpoint] = msg
+				b.spendNotifications[*msg.targetOutpoint] = msg
 			case *confirmationsNotification:
 				b.confNotifications[*msg.txid] = msg
 			}
@@ -105,12 +109,25 @@ out:
 
 			// First, check if this transaction spends an output
 			// that has an existing spend notification for it.
-			for _, txIn := range tx.TxIn {
+			for i, txIn := range tx.TxIn {
 				prevOut := txIn.PreviousOutPoint
 
+				// If this transaction indeed does spend an
+				// output which we have a registered notification
+				// for, then create a spend summary, finally
+				// sending off the details to the notification
+				// subscriber.
 				if ntfn, ok := b.spendNotifications[prevOut]; ok {
-					go triggerNtfn(ntfn.trigger)
+					spenderSha := tx.TxSha()
+					spendDetails := &chainntnfs.SpendDetail{
+						SpentOutPoint: ntfn.targetOutpoint,
+						SpenderTxHash: &spenderSha,
+						// TODO(roasbeef): copy tx?
+						SpendingTx:        &tx,
+						SpenderInputIndex: uint32(i),
+					}
 
+					ntfn.spendChan <- spendDetails
 					delete(b.spendNotifications, prevOut)
 				}
 			}
@@ -130,7 +147,7 @@ out:
 			// confirmation heap for future usage.
 			if confNtfn, ok := b.confNotifications[tx.TxSha()]; ok {
 				if confNtfn.numConfirmations == 1 {
-					go triggerNtfn(confNtfn.trigger)
+					confNtfn.finConf <- struct{}{}
 					break
 				}
 
@@ -158,7 +175,7 @@ out:
 			// is eligible until there are no more eligible entries.
 			nextConf := heap.Pop(b.confHeap).(*confEntry)
 			for nextConf.triggerHeight <= blockHeight {
-				triggerNtfn(nextConf.trigger)
+				nextConf.finConf <- struct{}{}
 
 				nextConf = heap.Pop(b.confHeap).(*confEntry)
 			}
@@ -168,6 +185,7 @@ out:
 			// TODO(roasbeef): re-orgs
 			//  * second channel to notify of confirmation decrementing
 			//    re-org?
+			//  * notify of negative confirmations
 			fmt.Println(delBlockNtfn)
 		case <-b.quit:
 			break out
@@ -197,9 +215,25 @@ func (b *BtcdNotifier) initAllNotifications() error {
 
 // spendNotification....
 type spendNotification struct {
-	outpoint *wire.OutPoint
+	targetOutpoint *wire.OutPoint
 
-	trigger *chainntnfs.NotificationTrigger
+	spendChan chan *chainntnfs.SpendDetail
+}
+
+// RegisterSpendNotification...
+// NOTE: eventChan MUST be buffered
+func (b *BtcdNotifier) RegisterSpendNtfn(outpoint *wire.OutPoint) (*chainntnfs.SpendEvent, error) {
+
+	// TODO(roasbeef): also register with rpc client? bool?
+
+	ntfn := &spendNotification{
+		targetOutpoint: outpoint,
+		spendChan:      make(chan *chainntnfs.SpendDetail, 1),
+	}
+
+	b.notificationRegistry <- ntfn
+
+	return &chainntnfs.SpendEvent{ntfn.spendChan}, nil
 }
 
 // confirmationNotification...
@@ -210,45 +244,25 @@ type confirmationsNotification struct {
 	initialConfirmHeight uint32
 	numConfirmations     uint32
 
-	trigger *chainntnfs.NotificationTrigger
-}
-
-// RegisterSpendNotification...
-// NOTE: eventChan MUST be buffered
-func (b *BtcdNotifier) RegisterSpendNotification(outpoint *wire.OutPoint,
-	trigger *chainntnfs.NotificationTrigger) error {
-
-	// TODO(roasbeef): also register with rpc client? bool?
-
-	ntfn := &spendNotification{
-		outpoint: outpoint,
-		trigger:  trigger,
-	}
-
-	b.notificationRegistry <- ntfn
-
-	return nil
+	finConf      chan struct{}
+	negativeConf chan uint32
 }
 
 // RegisterConfirmationsNotification...
-func (b *BtcdNotifier) RegisterConfirmationsNotification(txid *wire.ShaHash,
-	numConfs uint32, trigger *chainntnfs.NotificationTrigger) error {
+func (b *BtcdNotifier) RegisterConfirmationsNtfn(txid *wire.ShaHash,
+	numConfs uint32) (*chainntnfs.ConfirmationEvent, error) {
 
 	ntfn := &confirmationsNotification{
 		txid:             txid,
 		numConfirmations: numConfs,
-		trigger:          trigger,
+		finConf:          make(chan struct{}, 1),
+		negativeConf:     make(chan uint32, 1),
 	}
 
 	b.notificationRegistry <- ntfn
 
-	return nil
-}
-
-func triggerNtfn(t *chainntnfs.NotificationTrigger) {
-	if t.Callback != nil {
-		go t.Callback()
-	}
-
-	t.TriggerChan <- struct{}{}
+	return &chainntnfs.ConfirmationEvent{
+		Confirmed:    ntfn.finConf,
+		NegativeConf: ntfn.negativeConf,
+	}, nil
 }