lnwallet: once the reservation workflow is complete, wait then open the payment channel

* Hooks into the ChainNotifier infrastructure to receive a notification
once the funding transaction gets enough notifications.
* Still need to set up the notification grouting within a
LightningChannel to watch for uncooperative closures, and broadcasts
and revoked channel states.

lnwallet/channel.go

@@ -29,7 +29,7 @@ type PaymentHash [20]byte
 // TODO(roasbeef): future peer struct should embed this struct
 type LightningChannel struct {
 	lnwallet      *LightningWallet
-	channelEvents *chainntnfs.ChainNotifier
+	channelEvents chainntnfs.ChainNotifier
 
 	// TODO(roasbeef): Stores all previous R values + timeouts for each
 	// commitment update, plus some other meta-data...Or just use OP_RETURN
@@ -39,7 +39,7 @@ type LightningChannel struct {
 
 	// stateMtx protects concurrent access to the state struct.
 	stateMtx     sync.RWMutex
-	channelState channeldb.OpenChannel
+	channelState *channeldb.OpenChannel
 
 	updateTotem chan struct{}
 
@@ -61,8 +61,8 @@ type LightningChannel struct {
 }
 
 // newLightningChannel...
-func newLightningChannel(wallet *LightningWallet, events *chainntnfs.ChainNotifier,
+func newLightningChannel(wallet *LightningWallet, events chainntnfs.ChainNotifier,
-	chanDB *channeldb.DB, state channeldb.OpenChannel) (*LightningChannel, error) {
+	chanDB *channeldb.DB, state *channeldb.OpenChannel) (*LightningChannel, error) {
 
 	lc := &LightningChannel{
 		lnwallet:           wallet,
@@ -74,6 +74,9 @@ func newLightningChannel(wallet *LightningWallet, events *chainntnfs.ChainNotifi
 		unfufilledPayments: make(map[PaymentHash]*PaymentRequest),
 	}
 
+	// TODO(roasbeef): do a NotifySpent for the funding input, and
+	// NotifyReceived for all commitment outputs.
+
 	// Populate the totem.
 	lc.updateTotem <- struct{}{}
 
@@ -318,7 +321,7 @@ func (lc *LightningChannel) AddHTLC(timeout uint32, value btcutil.Amount,
 
 	// Re-create copies of the current commitment transactions to be updated.
 	ourNewCommitTx, theirNewCommitTx, err := createNewCommitmentTxns(
-		lc.fundingTxIn, &lc.channelState, chanUpdate, amountToUs, amountToThem,
+		lc.fundingTxIn, lc.channelState, chanUpdate, amountToUs, amountToThem,
 	)
 	if err != nil {
 		return nil, err
@@ -463,7 +466,7 @@ func (lc *LightningChannel) SettleHTLC(rValue [20]byte, newRevocation [20]byte)
 	// Create new commitment transactions that reflect the settlement of
 	// this pending HTLC.
 	ourNewCommitTx, theirNewCommitTx, err := createNewCommitmentTxns(
-		lc.fundingTxIn, &lc.channelState, chanUpdate, amountToUs, amountToThem,
+		lc.fundingTxIn, lc.channelState, chanUpdate, amountToUs, amountToThem,
 	)
 	if err != nil {
 		return nil, err

lnwallet/reservation.go

@@ -266,7 +266,7 @@ func (r *ChannelReservation) Cancel() error {
 // NOTE: If this method is called before .CompleteReservation(), it will block
 // indefinitely.
 func (r *ChannelReservation) WaitForChannelOpen() *LightningChannel {
-	return nil
+	return <-r.chanOpen
 }
 
 // * finish reset of tests

lnwallet/wallet.go

@@ -323,6 +323,7 @@ func NewLightningWallet(config *Config) (*LightningWallet, walletdb.DB, error) {
 		return nil, nil, err
 	}
 
+	// TODO(roasbeef): logging
 	return &LightningWallet{
 		db:            db,
 		chainNotifier: chainNotifier,
@@ -967,19 +968,36 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 	// which will be used for the lifetime of this channel.
 	err = l.ChannelDB.PutOpenChannel(pendingReservation.partialState)
 
-	// TODO(roasbeef): broadcast now?
+	// Create a goroutine to watch the chain so we can open the channel once
-	//  * create goroutine, listens on blockconnected+blockdisconnected channels
+	// the funding tx has enough confirmations.
-	//  * after six blocks, then will create an LightningChannel struct and
+	// TODO(roasbeef): add number of confs to the confi
-	//    send over reservation.
+	go l.openChannelAfterConfirmations(pendingReservation, 3)
-	//  * will need a multi-plexer to fan out, to listen on ListenConnectedBlocks
+
-	//    * should prob be a separate struct/modele
-	//  * use NotifySpent in order to catch non-cooperative spends of revoked
-	//    * NotifySpent(outpoints []*wire.OutPoint)
-	//    commitment txns. Hmm using p2sh or bare multi-sig?
-	//  * record partialState.CreationTime once tx is 'open'
 	msg.err <- err
 }
 
+// openChannelAfterConfirmations creates, and opens a payment channel after
+// the funding transaction created within the passed channel reservation
+// obtains the specified number of confirmations.
+func (l *LightningWallet) openChannelAfterConfirmations(res *ChannelReservation, numConfs uint32) {
+	// Register with the ChainNotifier for a notification once the funding
+	// transaction reaches `numConfs` confirmations.
+	trigger := &chainntnfs.NotificationTrigger{
+		TriggerChan: make(chan struct{}, 1),
+	}
+	txid := res.partialState.FundingTx.TxSha()
+	l.chainNotifier.RegisterConfirmationsNotification(&txid, numConfs, trigger)
+
+	// Wait until the specified number of confirmations has been reached.
+	<-trigger.TriggerChan
+
+	// Finally, create and officially open the payment channel!
+	// TODO(roasbeef): CreationTime once tx is 'open'
+	channel, _ := newLightningChannel(l, l.chainNotifier, l.ChannelDB,
+		res.partialState)
+	res.chanOpen <- channel
+}
+
 // getNextRawKey retrieves the next key within our HD key-chain for use within
 // as a multi-sig key within the funding transaction, or within the commitment
 // transaction's outputs.