eth/gasprice: add generic LRU implementation (#26162)

eth/gasprice/feehistory.go

@@ -56,7 +56,12 @@ type blockFees struct {
 	err     error
 }
 
-// processedFees contains the results of a processed block and is also used for caching
+type cacheKey struct {
+	number      uint64
+	percentiles string
+}
+
+// processedFees contains the results of a processed block.
 type processedFees struct {
 	reward               []*big.Int
 	baseFee, nextBaseFee *big.Int
@@ -268,13 +273,10 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks uint64, unresolvedL
 					oracle.processBlock(fees, rewardPercentiles)
 					results <- fees
 				} else {
-					cacheKey := struct {
+					cacheKey := cacheKey{number: blockNumber, percentiles: string(percentileKey)}
-						number      uint64
-						percentiles string
-					}{blockNumber, string(percentileKey)}
 
 					if p, ok := oracle.historyCache.Get(cacheKey); ok {
-						fees.results = p.(processedFees)
+						fees.results = p
 						results <- fees
 					} else {
 						if len(rewardPercentiles) != 0 {

eth/gasprice/gasprice.go

@@ -29,7 +29,7 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/log"
 	"github.com/XinFinOrg/XDPoSChain/params"
 	"github.com/XinFinOrg/XDPoSChain/rpc"
-	lru "github.com/hashicorp/golang-lru"
+	"github.com/XinFinOrg/XDPoSChain/common/lru"
 )
 
 const sampleNumber = 3 // Number of transactions sampled in a block
@@ -72,7 +72,8 @@ type Oracle struct {
 
 	checkBlocks, percentile           int
 	maxHeaderHistory, maxBlockHistory uint64
-	historyCache                      *lru.Cache
+
+	historyCache *lru.Cache[cacheKey, processedFees]
 }
 
 // NewOracle returns a new gasprice oracle which can recommend suitable
@@ -114,7 +115,7 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 		log.Warn("Sanitizing invalid gasprice oracle max block history", "provided", params.MaxBlockHistory, "updated", maxBlockHistory)
 	}
 
-	cache, _ := lru.New(2048)
+	cache := lru.NewCache[cacheKey, processedFees](2048)
 	headEvent := make(chan core.ChainHeadEvent, 1)
 	backend.SubscribeChainHeadEvent(headEvent)
 	go func() {