chainntnfs: add block cache to BtcdNotifier

This commit adds gives BtcdNotifier access to the block cache and wraps
its GetBlock method so that it uses the block cache.

chainntnfs/btcdnotify/btcd.go

@@ -14,6 +14,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/queue"
 )
@@ -69,6 +70,9 @@ type BtcdNotifier struct {
 
 	bestBlock chainntnfs.BlockEpoch
 
+	// blockCache is a LRU block cache.
+	blockCache *blockcache.BlockCache
+
 	chainUpdates *queue.ConcurrentQueue
 	txUpdates    *queue.ConcurrentQueue
 
@@ -94,7 +98,8 @@ var _ chainntnfs.ChainNotifier = (*BtcdNotifier)(nil)
 // accept new websockets clients.
 func New(config *rpcclient.ConnConfig, chainParams *chaincfg.Params,
 	spendHintCache chainntnfs.SpendHintCache,
-	confirmHintCache chainntnfs.ConfirmHintCache) (*BtcdNotifier, error) {
+	confirmHintCache chainntnfs.ConfirmHintCache,
+	blockCache *blockcache.BlockCache) (*BtcdNotifier, error) {
 
 	notifier := &BtcdNotifier{
 		chainParams: chainParams,
@@ -110,6 +115,8 @@ func New(config *rpcclient.ConnConfig, chainParams *chaincfg.Params,
 		spendHintCache:   spendHintCache,
 		confirmHintCache: confirmHintCache,
 
+		blockCache: blockCache,
+
 		quit: make(chan struct{}),
 	}
 
@@ -578,7 +585,7 @@ func (b *BtcdNotifier) confDetailsManually(confRequest chainntnfs.ConfRequest,
 		}
 
 		// TODO: fetch the neutrino filters instead.
-		block, err := b.chainConn.GetBlock(blockHash)
+		block, err := b.GetBlock(blockHash)
 		if err != nil {
 			return nil, chainntnfs.TxNotFoundManually,
 				fmt.Errorf("unable to get block with hash "+
@@ -616,7 +623,7 @@ func (b *BtcdNotifier) handleBlockConnected(epoch chainntnfs.BlockEpoch) error {
 	// First, we'll fetch the raw block as we'll need to gather all the
 	// transactions to determine whether any are relevant to our registered
 	// clients.
-	rawBlock, err := b.chainConn.GetBlock(epoch.Hash)
+	rawBlock, err := b.GetBlock(epoch.Hash)
 	if err != nil {
 		return fmt.Errorf("unable to get block: %v", err)
 	}
@@ -1012,3 +1019,11 @@ func (b *BtcdNotifier) RegisterBlockEpochNtfn(
 		}, nil
 	}
 }
+
+// GetBlock is used to retrieve the block with the given hash. This function
+// wraps the blockCache's GetBlock function.
+func (b *BtcdNotifier) GetBlock(hash *chainhash.Hash) (*wire.MsgBlock,
+	error) {
+
+	return b.blockCache.GetBlock(hash, b.chainConn.GetBlock)
+}

chainntnfs/btcdnotify/btcd_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/integration/rpctest"
+	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 )
@@ -53,9 +54,12 @@ func initHintCache(t *testing.T) *chainntnfs.HeightHintCache {
 // driver.
 func setUpNotifier(t *testing.T, h *rpctest.Harness) *BtcdNotifier {
 	hintCache := initHintCache(t)
+	blockCache := blockcache.NewBlockCache(10000)
 
 	rpcCfg := h.RPCConfig()
-	notifier, err := New(&rpcCfg, chainntnfs.NetParams, hintCache, hintCache)
+	notifier, err := New(
+		&rpcCfg, chainntnfs.NetParams, hintCache, hintCache, blockCache,
+	)
 	if err != nil {
 		t.Fatalf("unable to create notifier: %v", err)
 	}

chainntnfs/btcdnotify/driver.go

@@ -6,15 +6,16 @@ import (
 
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/rpcclient"
+	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 )
 
 // createNewNotifier creates a new instance of the ChainNotifier interface
 // implemented by BtcdNotifier.
 func createNewNotifier(args ...interface{}) (chainntnfs.ChainNotifier, error) {
-	if len(args) != 4 {
+	if len(args) != 5 {
 		return nil, fmt.Errorf("incorrect number of arguments to "+
-			".New(...), expected 4, instead passed %v", len(args))
+			".New(...), expected 5, instead passed %v", len(args))
 	}
 
 	config, ok := args[0].(*rpcclient.ConnConfig)
@@ -41,7 +42,15 @@ func createNewNotifier(args ...interface{}) (chainntnfs.ChainNotifier, error) {
 			"is incorrect, expected a chainntnfs.ConfirmHintCache")
 	}
 
-	return New(config, chainParams, spendHintCache, confirmHintCache)
+	blockCache, ok := args[4].(*blockcache.BlockCache)
+	if !ok {
+		return nil, errors.New("fifth argument to btcdnotify.New " +
+			"is incorrect, expected a *blockcache.BlockCache")
+	}
+
+	return New(
+		config, chainParams, spendHintCache, confirmHintCache, blockCache,
+	)
 }
 
 // init registers a driver for the BtcdNotifier concrete implementation of the

chainntnfs/test/test_interface.go

@@ -1955,7 +1955,7 @@ func TestInterfaces(t *testing.T, targetBackEnd string) {
 			newNotifier = func() (chainntnfs.TestChainNotifier, error) {
 				return btcdnotify.New(
 					&rpcConfig, chainntnfs.NetParams,
-					hintCache, hintCache,
+					hintCache, hintCache, blockCache,
 				)
 			}