From ecf20ed35080d352bd7b7993303a3172dcc9b370 Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Wed, 24 Mar 2021 08:48:33 +0200
Subject: [PATCH] multi: init neutrino backend with block cache

This commit initializes the nwutrino backend with the lnd blockcache so
that the two can share a block cache instead of each having its own.
---
 chainreg/chainregistry.go |  6 ++----
 lnd.go                    | 14 +++++++++++---
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/chainreg/chainregistry.go b/chainreg/chainregistry.go
index db2d4b92..5093f788 100644
--- a/chainreg/chainregistry.go
+++ b/chainreg/chainregistry.go
@@ -235,7 +235,8 @@ type ChainControl struct {
 // full-node, another backed by a running bitcoind full-node, and the other
 // backed by a running neutrino light client instance. When running with a
 // neutrino light client instance, `neutrinoCS` must be non-nil.
-func NewChainControl(cfg *Config) (*ChainControl, func(), error) {
+func NewChainControl(cfg *Config, blockCache *blockcache.BlockCache) (
+	*ChainControl, func(), error) {
 
 	// Set the RPC config from the "home" chain. Multi-chain isn't yet
 	// active, so we'll restrict usage to a particular chain for now.
@@ -307,9 +308,6 @@ func NewChainControl(cfg *Config) (*ChainControl, func(), error) {
 			"cache: %v", err)
 	}
 
-	// Initialize a new block cache.
-	blockCache := blockcache.NewBlockCache(cfg.BlockCacheSize)
-
 	// If spv mode is active, then we'll be using a distinct set of
 	// chainControl interfaces that interface directly with the p2p network
 	// of the selected chain.
diff --git a/lnd.go b/lnd.go
index 8e05ee5d..2559d0aa 100644
--- a/lnd.go
+++ b/lnd.go
@@ -34,6 +34,7 @@ import (
 	"gopkg.in/macaroon.v2"
 
 	"github.com/lightningnetwork/lnd/autopilot"
+	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/build"
 	"github.com/lightningnetwork/lnd/cert"
 	"github.com/lightningnetwork/lnd/chainreg"
@@ -254,6 +255,9 @@ func Main(cfg *Config, lisCfg ListenerCfg, interceptor signal.Interceptor) error
 
 	defer cleanUp()
 
+	// Initialize a new block cache.
+	blockCache := blockcache.NewBlockCache(cfg.BlockCacheSize)
+
 	// Before starting the wallet, we'll create and start our Neutrino
 	// light client instance, if enabled, in order to allow it to sync
 	// while the rest of the daemon continues startup.
@@ -264,7 +268,7 @@ func Main(cfg *Config, lisCfg ListenerCfg, interceptor signal.Interceptor) error
 	var neutrinoCS *neutrino.ChainService
 	if mainChain.Node == "neutrino" {
 		neutrinoBackend, neutrinoCleanUp, err := initNeutrinoBackend(
-			cfg, mainChain.ChainDir,
+			cfg, mainChain.ChainDir, blockCache,
 		)
 		if err != nil {
 			err := fmt.Errorf("unable to initialize neutrino "+
@@ -549,7 +553,9 @@ func Main(cfg *Config, lisCfg ListenerCfg, interceptor signal.Interceptor) error
 		BlockCacheSize: cfg.BlockCacheSize,
 	}
 
-	activeChainControl, cleanup, err := chainreg.NewChainControl(chainControlCfg)
+	activeChainControl, cleanup, err := chainreg.NewChainControl(
+		chainControlCfg, blockCache,
+	)
 	if cleanup != nil {
 		defer cleanup()
 	}
@@ -1554,7 +1560,8 @@ func initializeDatabases(ctx context.Context,
 
 // initNeutrinoBackend inits a new instance of the neutrino light client
 // backend given a target chain directory to store the chain state.
-func initNeutrinoBackend(cfg *Config, chainDir string) (*neutrino.ChainService,
+func initNeutrinoBackend(cfg *Config, chainDir string,
+	blockCache *blockcache.BlockCache) (*neutrino.ChainService,
 	func(), error) {
 
 	// Both channel validation flags are false by default but their meaning
@@ -1662,6 +1669,7 @@ func initNeutrinoBackend(cfg *Config, chainDir string) (*neutrino.ChainService,
 			return ips, nil
 		},
 		AssertFilterHeader: headerStateAssertion,
+		BlockCache:         blockCache.Cache,
 	}
 
 	neutrino.MaxPeers = 8