From 0193669ed8a959d9f38f9728083bc11de1f518aa Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Thu, 18 Mar 2021 14:24:06 +0200
Subject: [PATCH] routing: add block cache to BitcoindFilteredChainView

This commit adds the block cache to the BitcoindFilteredChainView struct
and wraps its GetBlock function so that block cache is used.
---
 chainreg/chainregistry.go           |  4 +++-
 routing/chainview/bitcoind.go       | 18 ++++++++++++++++--
 routing/chainview/interface_test.go |  7 ++++++-
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/chainreg/chainregistry.go b/chainreg/chainregistry.go
index d3b84130..e81258fd 100644
--- a/chainreg/chainregistry.go
+++ b/chainreg/chainregistry.go
@@ -418,7 +418,9 @@ func NewChainControl(cfg *Config) (*ChainControl, func(), error) {
 		cc.ChainNotifier = bitcoindnotify.New(
 			bitcoindConn, cfg.ActiveNetParams.Params, hintCache, hintCache,
 		)
-		cc.ChainView = chainview.NewBitcoindFilteredChainView(bitcoindConn)
+		cc.ChainView = chainview.NewBitcoindFilteredChainView(
+			bitcoindConn, blockCache,
+		)
 		walletConfig.ChainSource = bitcoindConn.NewBitcoindClient()
 
 		// If we're not in regtest mode, then we'll attempt to use a
diff --git a/routing/chainview/bitcoind.go b/routing/chainview/bitcoind.go
index d793dfb7..9a298edd 100644
--- a/routing/chainview/bitcoind.go
+++ b/routing/chainview/bitcoind.go
@@ -12,6 +12,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/chain"
 	"github.com/btcsuite/btcwallet/wtxmgr"
+	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/channeldb"
 )
 
@@ -37,6 +38,9 @@ type BitcoindFilteredChainView struct {
 	// chainView.
 	blockQueue *blockEventQueue
 
+	// blockCache is an LRU block cache.
+	blockCache *blockcache.BlockCache
+
 	// filterUpdates is a channel in which updates to the utxo filter
 	// attached to this instance are sent over.
 	filterUpdates chan filterUpdate
@@ -61,12 +65,14 @@ var _ FilteredChainView = (*BitcoindFilteredChainView)(nil)
 // NewBitcoindFilteredChainView creates a new instance of a FilteredChainView
 // from RPC credentials and a ZMQ socket address for a bitcoind instance.
 func NewBitcoindFilteredChainView(
-	chainConn *chain.BitcoindConn) *BitcoindFilteredChainView {
+	chainConn *chain.BitcoindConn,
+	blockCache *blockcache.BlockCache) *BitcoindFilteredChainView {
 
 	chainView := &BitcoindFilteredChainView{
 		chainFilter:     make(map[wire.OutPoint]struct{}),
 		filterUpdates:   make(chan filterUpdate),
 		filterBlockReqs: make(chan *filterBlockReq),
+		blockCache:      blockCache,
 		quit:            make(chan struct{}),
 	}
 
@@ -390,7 +396,7 @@ func (b *BitcoindFilteredChainView) chainFilterer() {
 		case req := <-b.filterBlockReqs:
 			// First we'll fetch the block itself as well as some
 			// additional information including its height.
-			block, err := b.chainClient.GetBlock(req.blockHash)
+			block, err := b.GetBlock(req.blockHash)
 			if err != nil {
 				req.err <- err
 				req.resp <- nil
@@ -479,3 +485,11 @@ func (b *BitcoindFilteredChainView) FilteredBlocks() <-chan *FilteredBlock {
 func (b *BitcoindFilteredChainView) DisconnectedBlocks() <-chan *FilteredBlock {
 	return b.blockQueue.staleBlocks
 }
+
+// GetBlock is used to retrieve the block with the given hash. This function
+// wraps the blockCache's GetBlock function.
+func (b *BitcoindFilteredChainView) GetBlock(hash *chainhash.Hash) (
+	*wire.MsgBlock, error) {
+
+	return b.blockCache.GetBlock(hash, b.chainClient.GetBlock)
+}
diff --git a/routing/chainview/interface_test.go b/routing/chainview/interface_test.go
index 33975e0a..875c0601 100644
--- a/routing/chainview/interface_test.go
+++ b/routing/chainview/interface_test.go
@@ -26,6 +26,7 @@ import (
 	_ "github.com/btcsuite/btcwallet/walletdb/bdb" // Required to register the boltdb walletdb implementation.
 
 	"github.com/lightninglabs/neutrino"
+	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/kvdb"
 )
@@ -844,7 +845,11 @@ var interfaceImpls = []struct {
 				cleanUp2()
 			}
 
-			chainView := NewBitcoindFilteredChainView(chainConn)
+			blockCache := blockcache.NewBlockCache(10000)
+
+			chainView := NewBitcoindFilteredChainView(
+				chainConn, blockCache,
+			)
 
 			return cleanUp3, chainView, nil
 		},