common: introduce IsHexHash and use it (#32998)

Author: mask-pp

cmd/geth/config.go

@@ -35,7 +35,6 @@ import (
 	"github.com/ethereum/go-ethereum/beacon/blsync"
 	"github.com/ethereum/go-ethereum/cmd/utils"
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/eth/catalyst"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
@@ -273,11 +272,11 @@ func makeFullNode(ctx *cli.Context) *node.Node {
 	// Configure synchronization override service
 	var synctarget common.Hash
 	if ctx.IsSet(utils.SyncTargetFlag.Name) {
-		hex := hexutil.MustDecode(ctx.String(utils.SyncTargetFlag.Name))
-		if len(hex) != common.HashLength {
-			utils.Fatalf("invalid sync target length: have %d, want %d", len(hex), common.HashLength)
+		target := ctx.String(utils.SyncTargetFlag.Name)
+		if !common.IsHexHash(target) {
+			utils.Fatalf("sync target hash is not a valid hex hash: %s", target)
 		}
-		synctarget = common.BytesToHash(hex)
+		synctarget = common.HexToHash(target)
 	}
 	utils.RegisterSyncOverrideService(stack, eth, synctarget, ctx.Bool(utils.ExitWhenSyncedFlag.Name))
 

cmd/geth/snapshot.go

@@ -639,11 +639,11 @@ func snapshotExportPreimages(ctx *cli.Context) error {
 
 	var root common.Hash
 	if ctx.NArg() > 1 {
-		rootBytes := common.FromHex(ctx.Args().Get(1))
-		if len(rootBytes) != common.HashLength {
+		hash := ctx.Args().Get(1)
+		if !common.IsHexHash(hash) {
 			return fmt.Errorf("invalid hash: %s", ctx.Args().Get(1))
 		}
-		root = common.BytesToHash(rootBytes)
+		root = common.HexToHash(hash)
 	} else {
 		headBlock := rawdb.ReadHeadBlock(chaindb)
 		if headBlock == nil {

common/types.go

@@ -71,6 +71,15 @@ func BigToHash(b *big.Int) Hash { return BytesToHash(b.Bytes()) }
 // If b is larger than len(h), b will be cropped from the left.
 func HexToHash(s string) Hash { return BytesToHash(FromHex(s)) }
 
+// IsHexHash verifies whether a string can represent a valid hex-encoded
+// Ethereum hash or not.
+func IsHexHash(s string) bool {
+	if has0xPrefix(s) {
+		s = s[2:]
+	}
+	return len(s) == 2*HashLength && isHex(s)
+}
+
 // Cmp compares two hashes.
 func (h Hash) Cmp(other Hash) int {
 	return bytes.Compare(h[:], other[:])