_

services/wallet/balance_cache.go

@@ -8,20 +8,20 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 )
 
-type BalanceCache struct {
+type balanceCache struct {
+	// cache maps an address to a map of a block number and the balance of this particular address
 	cache map[common.Address]map[*big.Int]*big.Int
 	lock  sync.RWMutex
 }
 
-func (b *BalanceCache) readCachedBalance(account common.Address, blockNumber *big.Int) (*big.Int, bool) {
+func (b *balanceCache) readCachedBalance(account common.Address, blockNumber *big.Int) *big.Int {
 	b.lock.RLock()
 	defer b.lock.RUnlock()
 
-	balance, exists := b.cache[account][blockNumber]
-	return balance, exists
+	return b.cache[account][blockNumber]
 }
 
-func (b *BalanceCache) addBalanceToCache(account common.Address, blockNumber *big.Int, balance *big.Int) {
+func (b *balanceCache) addBalanceToCache(account common.Address, blockNumber *big.Int, balance *big.Int) {
 	b.lock.Lock()
 	defer b.lock.Unlock()
 
@@ -32,24 +32,22 @@ func (b *BalanceCache) addBalanceToCache(account common.Address, blockNumber *bi
 	b.cache[account][blockNumber] = balance
 }
 
-func (b *BalanceCache) BalanceAt(client BalanceReader, ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error) {
-	cachedBalance, exists := b.readCachedBalance(account, blockNumber)
-	if exists {
+func (b *balanceCache) BalanceAt(client BalanceReader, ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error) {
+	cachedBalance := b.readCachedBalance(account, blockNumber)
+	if cachedBalance != nil {
 		return cachedBalance, nil
-	} else {
-		balance, err := client.BalanceAt(ctx, account, blockNumber)
-		if err != nil {
-			return nil, err
-		}
-		b.addBalanceToCache(account, blockNumber, balance)
-
-		return balance, nil
 	}
+	balance, err := client.BalanceAt(ctx, account, blockNumber)
+	if err != nil {
+		return nil, err
+	}
+	b.addBalanceToCache(account, blockNumber, balance)
+
+	return balance, nil
 }
 
-func NewBalanceCache() *BalanceCache {
-	return &BalanceCache{
+func newBalanceCache() *balanceCache {
+	return &balanceCache{
 		cache: make(map[common.Address]map[*big.Int]*big.Int),
-		lock:  sync.RWMutex{},
 	}
 }

services/wallet/commands.go

@@ -18,7 +18,7 @@ type ethHistoricalCommand struct {
 	eth          TransferDownloader
 	address      common.Address
 	client       reactorClient
-	balanceCache *BalanceCache
+	balanceCache *balanceCache
 	feed         *event.Feed
 
 	from, to *big.Int
@@ -325,7 +325,7 @@ func (c *controlCommand) fastIndex(ctx context.Context, to *DBHeader) error {
 		eth := &ethHistoricalCommand{
 			db:           c.db,
 			client:       c.client,
-			balanceCache: NewBalanceCache(),
+			balanceCache: newBalanceCache(),
 			address:      address,
 			eth: &ETHTransferDownloader{
 				client:   c.client,

services/wallet/concurrent.go

@@ -45,18 +45,18 @@ type TransferDownloader interface {
 	GetTransfersByNumber(context.Context, *big.Int) ([]Transfer, error)
 }
 
-func downloadEthConcurrently(c *ConcurrentDownloader, client BalanceReader, balanceCache *BalanceCache, downloader TransferDownloader, account common.Address, low, high *big.Int) {
+func downloadEthConcurrently(c *ConcurrentDownloader, client BalanceReader, cache *balanceCache, downloader TransferDownloader, account common.Address, low, high *big.Int) {
 	c.Add(func(ctx context.Context) error {
 		if low.Cmp(high) >= 0 {
 			return nil
 		}
 		log.Debug("eth transfers comparing blocks", "low", low, "high", high)
-		lb, err := balanceCache.BalanceAt(client, ctx, account, low)
+		lb, err := cache.BalanceAt(client, ctx, account, low)
 		//lb, err := client.BalanceAt(ctx, account, low)
 		if err != nil {
 			return err
 		}
-		hb, err := balanceCache.BalanceAt(client, ctx, account, high)
+		hb, err := cache.BalanceAt(client, ctx, account, high)
 		//hb, err := client.BalanceAt(ctx, account, high)
 		if err != nil {
 			return err
@@ -93,10 +93,10 @@ func downloadEthConcurrently(c *ConcurrentDownloader, client BalanceReader, bala
 		}
 		mid := new(big.Int).Add(low, high)
 		mid = mid.Div(mid, two)
-		balanceCache.BalanceAt(client, ctx, account, mid)
+		cache.BalanceAt(client, ctx, account, mid)
 		log.Debug("balances are not equal. spawn two concurrent downloaders", "low", low, "mid", mid, "high", high)
-		downloadEthConcurrently(c, client, balanceCache, downloader, account, low, mid)
-		downloadEthConcurrently(c, client, balanceCache, downloader, account, mid, high)
+		downloadEthConcurrently(c, client, cache, downloader, account, low, mid)
+		downloadEthConcurrently(c, client, cache, downloader, account, mid, high)
 		return nil
 	})
 }

services/wallet/concurrent_test.go

@@ -109,7 +109,7 @@ func TestConcurrentEthDownloader(t *testing.T) {
 			defer cancel()
 			concurrent := NewConcurrentDownloader(ctx)
 			downloadEthConcurrently(
-				concurrent, tc.options.balances, NewBalanceCache(), tc.options.batches,
+				concurrent, tc.options.balances, newBalanceCache(), tc.options.batches,
 				common.Address{}, zero, tc.options.last)
 			concurrent.Wait()
 			require.NoError(t, concurrent.Error())