consensus/clique: unduplicate header encoding

consensus/clique/clique.go

@@ -20,6 +20,7 @@ package clique
 import (
 	"bytes"
 	"errors"
+	"io"
 	"math/big"
 	"math/rand"
 	"sync"
@@ -665,30 +666,6 @@ func (c *Clique) SealHash(header *types.Header) common.Hash {
 	return SealHash(header)
 }
 
-// SealHash returns the hash of a block prior to it being sealed.
-func SealHash(header *types.Header) (hash common.Hash) {
-	hasher := sha3.NewLegacyKeccak256()
-	rlp.Encode(hasher, []interface{}{
-		header.ParentHash,
-		header.UncleHash,
-		header.Coinbase,
-		header.Root,
-		header.TxHash,
-		header.ReceiptHash,
-		header.Bloom,
-		header.Difficulty,
-		header.Number,
-		header.GasLimit,
-		header.GasUsed,
-		header.Time,
-		header.Extra[:len(header.Extra)-65], // Yes, this will panic if extra is too short
-		header.MixDigest,
-		header.Nonce,
-	})
-	hasher.Sum(hash[:0])
-	return hash
-}
-
 // Close implements consensus.Engine. It's a noop for clique as there are no background threads.
 func (c *Clique) Close() error {
 	return nil
@@ -705,6 +682,14 @@ func (c *Clique) APIs(chain consensus.ChainReader) []rpc.API {
 	}}
 }
 
+// SealHash returns the hash of a block prior to it being sealed.
+func SealHash(header *types.Header) (hash common.Hash) {
+	hasher := sha3.NewLegacyKeccak256()
+	encodeSigHeader(hasher, header)
+	hasher.Sum(hash[:0])
+	return hash
+}
+
 // CliqueRLP returns the rlp bytes which needs to be signed for the proof-of-authority
 // sealing. The RLP to sign consists of the entire header apart from the 65 byte signature
 // contained at the end of the extra data.
@@ -713,7 +698,13 @@ func (c *Clique) APIs(chain consensus.ChainReader) []rpc.API {
 // panics. This is done to avoid accidentally using both forms (signature present
 // or not), which could be abused to produce different hashes for the same header.
 func CliqueRLP(header *types.Header) []byte {
-	data, _ := rlp.EncodeToBytes([]interface{}{
+	b := new(bytes.Buffer)
+	encodeSigHeader(b, header)
+	return b.Bytes()
+}
+
+func encodeSigHeader(w io.Writer, header *types.Header) {
+	err := rlp.Encode(w, []interface{}{
 		header.ParentHash,
 		header.UncleHash,
 		header.Coinbase,
@@ -730,5 +721,7 @@ func CliqueRLP(header *types.Header) []byte {
 		header.MixDigest,
 		header.Nonce,
 	})
-	return data
+	if err != nil {
+		panic("can't encode: " + err.Error())
+	}
 }