chainntfs: switch BtcdNotifier to directly use btcrpcclient

* Turns out the NotificationServer on btcwallet doesn’t sever full
blocks, nor notify for arbitrary transactions. Instead, we now create a
new client specifically for BtcdNotifier.

* Final implementation is simpler, less dependent on newer btcwallet
features in flux. Additionally, this decouples the chain notifications
from the wallet. Enabling reliance on btcd for notifications, in
conjunction with an independent wallet that satisfies the to-be-drafted
Wallet interface.

chainntfs/btcdnotify/btcd.go

@@ -1,16 +1,16 @@
 package btcdnotify
 
 import (
-	"bytes"
 	"container/heap"
 	"fmt"
 	"sync"
 	"sync/atomic"
+	"time"
 
+	"github.com/btcsuite/btcd/btcjson"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcwallet/chain"
+	"github.com/btcsuite/btcrpcclient"
-	btcwallet "github.com/btcsuite/btcwallet/wallet"
+	"github.com/btcsuite/btcutil"
-	"github.com/btcsuite/btcwallet/wtxmgr"
 	"github.com/lightningnetwork/lnd/chainntfs"
 )
 
@@ -19,8 +19,7 @@ type BtcdNotifier struct {
 	started int32 // To be used atomically
 	stopped int32 // To be used atomically
 
-	ntfnSource *btcwallet.NotificationServer
+	chainConn *btcrpcclient.Client
-	chainConn  *chain.RPCClient
 
 	notificationRegistry chan interface{}
 
@@ -30,9 +29,9 @@ type BtcdNotifier struct {
 	confNotifications  map[wire.ShaHash]*confirmationsNotification
 	confHeap           *confirmationHeap
 
-	connectedBlocks    <-chan wtxmgr.BlockMeta
+	connectedBlockHashes    chan *blockNtfn
-	disconnectedBlocks <-chan wtxmgr.BlockMeta
+	disconnectedBlockHashes chan *blockNtfn
-	relevantTxs        <-chan chain.RelevantTx
+	relevantTxs             chan *btcutil.Tx
 
 	wg   sync.WaitGroup
 	quit chan struct{}
@@ -41,15 +40,12 @@ type BtcdNotifier struct {
 var _ chainntnfs.ChainNotifier = (*BtcdNotifier)(nil)
 
 // NewBtcdNotifier...
-// TODO(roasbeef): chain client + notification sever
+// TODO(roasbeef):
-//  * use server for notifications
 //  * when asked for spent, request via client
-func NewBtcdNotifier(ntfnSource *btcwallet.NotificationServer,
+//func NewBtcdNotifier(ntfnSource *btcwallet.NotificationServer,
-	chainConn *chain.RPCClient) (*BtcdNotifier, error) {
+//	chainConn *chain.RPCClient) (*BtcdNotifier, error) {
-
+func NewBtcdNotifier(config *btcrpcclient.ConnConfig) (*BtcdNotifier, error) {
-	return &BtcdNotifier{
+	notifier := &BtcdNotifier{
-		ntfnSource: ntfnSource,
-		chainConn:  chainConn,
 
 		notificationRegistry: make(chan interface{}),
 
@@ -57,12 +53,28 @@ func NewBtcdNotifier(ntfnSource *btcwallet.NotificationServer,
 		confNotifications:  make(map[wire.ShaHash]*confirmationsNotification),
 		confHeap:           newConfirmationHeap(),
 
-		connectedBlocks:    make(chan wtxmgr.BlockMeta),
+		connectedBlockHashes:    make(chan *blockNtfn, 20),
-		disconnectedBlocks: make(chan wtxmgr.BlockMeta),
+		disconnectedBlockHashes: make(chan *blockNtfn, 20),
-		relevantTxs:        make(chan chain.RelevantTx),
+		relevantTxs:             make(chan *btcutil.Tx, 100),
 
 		quit: make(chan struct{}),
-	}, nil
+	}
+
+	ntfnCallbacks := &btcrpcclient.NotificationHandlers{
+		OnBlockConnected:    notifier.onBlockConnected,
+		OnBlockDisconnected: notifier.onBlockDisconnected,
+		OnRedeemingTx:       notifier.onRedeemingTx,
+	}
+
+	config.DisableConnectOnNew = true
+	config.DisableAutoReconnect = false
+	chainConn, err := btcrpcclient.New(config, ntfnCallbacks)
+	if err != nil {
+		return nil, err
+	}
+	notifier.chainConn = chainConn
+
+	return notifier, nil
 }
 
 // Start...
@@ -72,6 +84,14 @@ func (b *BtcdNotifier) Start() error {
 		return nil
 	}
 
+	if err := b.chainConn.Connect(20); err != nil {
+		return err
+	}
+
+	if err := b.chainConn.NotifyBlocks(); err != nil {
+		return err
+	}
+
 	b.wg.Add(1)
 	go b.notificationDispatcher()
 
@@ -85,16 +105,43 @@ func (b *BtcdNotifier) Stop() error {
 		return nil
 	}
 
+	b.chainConn.Shutdown()
+
 	close(b.quit)
 	b.wg.Wait()
 
 	return nil
 }
 
+// connectedBlock...
+type blockNtfn struct {
+	sha    *wire.ShaHash
+	height int32
+}
+
+// onBlockConnected...
+func (b *BtcdNotifier) onBlockConnected(hash *wire.ShaHash, height int32, t time.Time) {
+	select {
+	case b.connectedBlockHashes <- &blockNtfn{hash, height}:
+	case <-b.quit:
+	}
+}
+
+// onBlockDisconnected...
+func (b *BtcdNotifier) onBlockDisconnected(hash *wire.ShaHash, height int32, t time.Time) {
+	b.onBlockDisconnected(hash, height, t)
+}
+
+// onRedeemingTx...
+func (b *BtcdNotifier) onRedeemingTx(transaction *btcutil.Tx, details *btcjson.BlockDetails) {
+	select {
+	case b.relevantTxs <- transaction:
+	case <-b.quit:
+	}
+}
+
 // notificationDispatcher...
 func (b *BtcdNotifier) notificationDispatcher() {
-	ntfnClient := b.ntfnSource.TransactionNotifications()
-
 out:
 	for {
 		select {
@@ -105,66 +152,73 @@ out:
 			case *confirmationsNotification:
 				b.confNotifications[*msg.txid] = msg
 			}
-		case txNtfn := <-ntfnClient.C:
+		case staleBlockHash := <-b.disconnectedBlockHashes:
-			// We're only concerned with newly mined blocks which
-			// may or may not include transactions we are interested
-			// in.
-			if txNtfn.AttachedBlocks == nil {
-				break
-			}
-
-			newBlocks := txNtfn.AttachedBlocks
-			for _, block := range newBlocks {
-				blockHeight := uint32(block.Height)
-
-				// Examine all transactions within the block
-				// in order to determine if this block includes a
-				// transactions spending one of the registered
-				// outpoints of interest.
-				for _, txSummary := range block.Transactions {
-					txBytes := bytes.NewReader(txSummary.Transaction)
-					tx := wire.NewMsgTx()
-					if err := tx.Deserialize(txBytes); err != nil {
-						// TODO(roasbeef): err
-						fmt.Println("unable to des tx: ", err)
-						continue
-					}
-
-					// Check if the inclusion of this transaction
-					// within a block by itself triggers a block
-					// confirmation threshold, if so send a
-					// notification. Otherwise, place the notification
-					// on a heap to be triggered in the future once
-					// additional confirmations are attained.
-					txSha := tx.TxSha()
-					b.checkConfirmationTrigger(&txSha, blockHeight)
-
-					// Next, examine all the inputs spent, firing
-					// of a notification if it spends any of the
-					// outpoints within the set of our registered
-					// outputs.
-					b.checkSpendTrigger(tx)
-				}
-
-				// A new block has been connected to the main
-				// chain. Send out any N confirmation notifications
-				// which may have been triggered by this new block.
-				b.notifyConfs(blockHeight)
-			}
-
 			// TODO(roasbeef): re-orgs
 			//  * second channel to notify of confirmation decrementing
 			//    re-org?
 			//  * notify of negative confirmations
-			fmt.Println(txNtfn.DetachedBlocks)
+			fmt.Println(staleBlockHash)
+		case connectedBlock := <-b.connectedBlockHashes:
+			newBlock, err := b.chainConn.GetBlock(connectedBlock.sha)
+			if err != nil {
+				continue
+			}
+
+			newHeight := connectedBlock.height
+			for _, tx := range newBlock.Transactions() {
+				// Check if the inclusion of this transaction
+				// within a block by itself triggers a block
+				// confirmation threshold, if so send a
+				// notification. Otherwise, place the notification
+				// on a heap to be triggered in the future once
+				// additional confirmations are attained.
+				txSha := tx.Sha()
+				b.checkConfirmationTrigger(txSha, newHeight)
+			}
+
+			// A new block has been connected to the main
+			// chain. Send out any N confirmation notifications
+			// which may have been triggered by this new block.
+			b.notifyConfs(newHeight)
+		case newSpend := <-b.relevantTxs:
+			// First, check if this transaction spends an output
+			// that has an existing spend notification for it.
+			for i, txIn := range newSpend.MsgTx().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 {
+					spenderSha := newSpend.Sha()
+					spendDetails := &chainntnfs.SpendDetail{
+						SpentOutPoint: ntfn.targetOutpoint,
+						SpenderTxHash: spenderSha,
+						// TODO(roasbeef): copy tx?
+						SpendingTx:        newSpend.MsgTx(),
+						SpenderInputIndex: uint32(i),
+					}
+
+					ntfn.spendChan <- spendDetails
+					delete(b.spendNotifications, prevOut)
+				}
+			}
 		case <-b.quit:
 			break out
 		}
 	}
+	b.wg.Done()
 }
 
 // notifyConfs...
-func (b *BtcdNotifier) notifyConfs(newBlockHeight uint32) {
+func (b *BtcdNotifier) notifyConfs(newBlockHeight int32) {
+	// If the heap is empty, we have nothing to do.
+	if b.confHeap.Len() == 0 {
+		return
+	}
+
 	// Traverse our confirmation heap. The heap is a
 	// min-heap, so the confirmation notification which requires
 	// the smallest block-height will always be at the top
@@ -172,52 +226,29 @@ func (b *BtcdNotifier) notifyConfs(newBlockHeight uint32) {
 	// for triggering, then fire it off, and check if another
 	// is eligible until there are no more eligible entries.
 	nextConf := heap.Pop(b.confHeap).(*confEntry)
-	for nextConf.triggerHeight <= newBlockHeight {
+	for nextConf.triggerHeight <= uint32(newBlockHeight) {
 		nextConf.finConf <- struct{}{}
 
+		if b.confHeap.Len() == 0 {
+			return
+		}
+
 		nextConf = heap.Pop(b.confHeap).(*confEntry)
 	}
 
 	heap.Push(b.confHeap, nextConf)
 }
 
-// checkSpendTrigger...
-func (b *BtcdNotifier) checkSpendTrigger(tx *wire.MsgTx) {
-	// First, check if this transaction spends an output
-	// that has an existing spend notification for it.
-	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 {
-			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)
-		}
-	}
-}
-
 // checkConfirmationTrigger...
-func (b *BtcdNotifier) checkConfirmationTrigger(txSha *wire.ShaHash,
+// TODO(roasbeef): perheps lookup, then track by inputs instead?
-	blockHeight uint32) {
+func (b *BtcdNotifier) checkConfirmationTrigger(txSha *wire.ShaHash, blockHeight int32) {
 	// If a confirmation notification has been registered
 	// for this txid, then either trigger a notification
 	// event if only a single confirmation notification was
 	// requested, or place the notification on the
 	// confirmation heap for future usage.
 	if confNtfn, ok := b.confNotifications[*txSha]; ok {
+		delete(b.confNotifications, *txSha)
 		if confNtfn.numConfirmations == 1 {
 			confNtfn.finConf <- struct{}{}
 			return
@@ -229,10 +260,11 @@ func (b *BtcdNotifier) checkConfirmationTrigger(txSha *wire.ShaHash,
 		// The heapConf allows us to easily keep track of
 		// which notification(s) we should fire off with
 		// each incoming block.
-		confNtfn.initialConfirmHeight = blockHeight
+		confNtfn.initialConfirmHeight = uint32(blockHeight)
+		finalConfHeight := uint32(confNtfn.initialConfirmHeight + confNtfn.numConfirmations - 1)
 		heapEntry := &confEntry{
 			confNtfn,
-			confNtfn.initialConfirmHeight + confNtfn.numConfirmations,
+			finalConfHeight,
 		}
 		heap.Push(b.confHeap, heapEntry)
 	}
@@ -248,8 +280,9 @@ type spendNotification struct {
 // RegisterSpendNotification...
 // NOTE: eventChan MUST be buffered
 func (b *BtcdNotifier) RegisterSpendNtfn(outpoint *wire.OutPoint) (*chainntnfs.SpendEvent, error) {
-
+	if err := b.chainConn.NotifySpent([]*wire.OutPoint{outpoint}); err != nil {
-	// TODO(roasbeef): also register with rpc client? bool?
+		return nil, err
+	}
 
 	ntfn := &spendNotification{
 		targetOutpoint: outpoint,
@@ -270,7 +303,7 @@ type confirmationsNotification struct {
 	numConfirmations     uint32
 
 	finConf      chan struct{}
-	negativeConf chan uint32
+	negativeConf chan int32
 }
 
 // RegisterConfirmationsNotification...
@@ -281,7 +314,7 @@ func (b *BtcdNotifier) RegisterConfirmationsNtfn(txid *wire.ShaHash,
 		txid:             txid,
 		numConfirmations: numConfs,
 		finConf:          make(chan struct{}, 1),
-		negativeConf:     make(chan uint32, 1),
+		negativeConf:     make(chan int32, 1),
 	}
 
 	b.notificationRegistry <- ntfn