From 0efbc0b7946c6d9cbb2527d61b560fcee9d511d2 Mon Sep 17 00:00:00 2001
From: Hadrien Croubois <hadrien.croubois@gmail.com>
Date: Thu, 7 Mar 2024 15:05:04 +0100
Subject: [PATCH] add pragueSigner

---
 core/types/transaction_signing.go | 74 ++++++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/core/types/transaction_signing.go b/core/types/transaction_signing.go
index 70dee0776e..047d180295 100644
--- a/core/types/transaction_signing.go
+++ b/core/types/transaction_signing.go
@@ -40,6 +40,8 @@ type sigCache struct {
 func MakeSigner(config *params.ChainConfig, blockNumber *big.Int, blockTime uint64) Signer {
 	var signer Signer
 	switch {
+	case config.IsPrague(blockNumber, blockTime):
+		signer = NewPragueSigner(config.ChainID)
 	case config.IsCancun(blockNumber, blockTime):
 		signer = NewCancunSigner(config.ChainID)
 	case config.IsLondon(blockNumber):
@@ -65,6 +67,9 @@ func MakeSigner(config *params.ChainConfig, blockNumber *big.Int, blockTime uint
 // have the current block number available, use MakeSigner instead.
 func LatestSigner(config *params.ChainConfig) Signer {
 	if config.ChainID != nil {
+		if config.PragueTime != nil {
+			return NewPragueSigner(config.ChainID)
+		}
 		if config.CancunTime != nil {
 			return NewCancunSigner(config.ChainID)
 		}
@@ -92,7 +97,7 @@ func LatestSignerForChainID(chainID *big.Int) Signer {
 	if chainID == nil {
 		return HomesteadSigner{}
 	}
-	return NewCancunSigner(chainID)
+	return NewPragueSigner(chainID)
 }
 
 // SignTx signs the transaction using the given signer and private key.
@@ -169,6 +174,73 @@ type Signer interface {
 	Equal(Signer) bool
 }
 
+type pragueSigner struct{ cancunSigner }
+
+// NewPragueSigner returns a signer that accepts
+// - EIP-5806 delegate transactions
+// - EIP-4844 blob transactions
+// - EIP-1559 dynamic fee transactions
+// - EIP-2930 access list transactions,
+// - EIP-155 replay protected transactions, and
+// - legacy Homestead transactions.
+func NewPragueSigner(chainId *big.Int) Signer {
+	return pragueSigner{cancunSigner{londonSigner{eip2930Signer{NewEIP155Signer(chainId)}}}}
+}
+
+func (s pragueSigner) Sender(tx *Transaction) (common.Address, error) {
+	if tx.Type() != DelegateTxType {
+		return s.cancunSigner.Sender(tx)
+	}
+	V, R, S := tx.RawSignatureValues()
+	// Delegate txs are defined to use 0 and 1 as their recovery
+	// id, add 27 to become equivalent to unprotected Homestead signatures.
+	V = new(big.Int).Add(V, big.NewInt(27))
+	if tx.ChainId().Cmp(s.chainId) != 0 {
+		return common.Address{}, fmt.Errorf("%w: have %d want %d", ErrInvalidChainId, tx.ChainId(), s.chainId)
+	}
+	return recoverPlain(s.Hash(tx), R, S, V, true)
+}
+
+func (s pragueSigner) Equal(s2 Signer) bool {
+	x, ok := s2.(cancunSigner)
+	return ok && x.chainId.Cmp(s.chainId) == 0
+}
+
+func (s pragueSigner) SignatureValues(tx *Transaction, sig []byte) (R, S, V *big.Int, err error) {
+	txdata, ok := tx.inner.(*DelegateTx)
+	if !ok {
+		return s.cancunSigner.SignatureValues(tx, sig)
+	}
+	// Check that chain ID of tx matches the signer. We also accept ID zero here,
+	// because it indicates that the chain ID was not specified in the tx.
+	if txdata.ChainID.Sign() != 0 && txdata.ChainID.Cmp(s.chainId) != 0 {
+		return nil, nil, nil, fmt.Errorf("%w: have %d want %d", ErrInvalidChainId, txdata.ChainID, s.chainId)
+	}
+	R, S, _ = decodeSignature(sig)
+	V = big.NewInt(int64(sig[64]))
+	return R, S, V, nil
+}
+
+// Hash returns the hash to be signed by the sender.
+// It does not uniquely identify the transaction.
+func (s pragueSigner) Hash(tx *Transaction) common.Hash {
+	if tx.Type() != DelegateTxType {
+		return s.cancunSigner.Hash(tx)
+	}
+	return prefixedRlpHash(
+		tx.Type(),
+		[]interface{}{
+			s.chainId,
+			tx.Nonce(),
+			tx.GasTipCap(),
+			tx.GasFeeCap(),
+			tx.Gas(),
+			tx.To(),
+			tx.Data(),
+			tx.AccessList(),
+		})
+}
+
 type cancunSigner struct{ londonSigner }
 
 // NewCancunSigner returns a signer that accepts