1 files changed, 59 insertions, 0 deletions
diff --git a/ethclient/signer.go b/ethclient/signer.go
new file mode 100644
index 0000000..4a9f645
--- /dev/null
+++ b/ethclient/signer.go
@@ -0,0 +1,59 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package ethclient
+
+import (
+	"errors"
+	"math/big"
+
+	"github.com/ava-labs/coreth/core/types"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+// senderFromServer is a types.Signer that remembers the sender address returned by the RPC
+// server. It is stored in the transaction's sender address cache to avoid an additional
+// request in TransactionSender.
+type senderFromServer struct {
+	addr      common.Address
+	blockhash common.Hash
+}
+
+var errNotCached = errors.New("sender not cached")
+
+func setSenderFromServer(tx *types.Transaction, addr common.Address, block common.Hash) {
+	// Use types.Sender for side-effect to store our signer into the cache.
+	types.Sender(&senderFromServer{addr, block}, tx)
+}
+
+func (s *senderFromServer) Equal(other types.Signer) bool {
+	os, ok := other.(*senderFromServer)
+	return ok && os.blockhash == s.blockhash
+}
+
+func (s *senderFromServer) Sender(tx *types.Transaction) (common.Address, error) {
+	if s.blockhash == (common.Hash{}) {
+		return common.Address{}, errNotCached
+	}
+	return s.addr, nil
+}
+
+func (s *senderFromServer) Hash(tx *types.Transaction) common.Hash {
+	panic("can't sign with senderFromServer")
+}
+func (s *senderFromServer) SignatureValues(tx *types.Transaction, sig []byte) (R, S, V *big.Int, err error) {
+	panic("can't sign with senderFromServer")
+}