[ETCM-1096] Transaction Signer skeleton

Author: strauss-m

src/main/scala/io/iohk/ethereum/signer/HomesteadLegacyTransactionSigner.scala

@@ -0,0 +1,21 @@
+package io.iohk.ethereum.signer
+
+import akka.util.ByteString
+
+import io.iohk.ethereum.crypto.ECDSASignature
+import io.iohk.ethereum.domain.Address
+import io.iohk.ethereum.domain.LegacyTransaction
+import io.iohk.ethereum.domain.SignedTransaction
+import io.iohk.ethereum.domain.Transaction
+
+class HomesteadLegacyTransactionSigner extends TransactionSigner[LegacyTransaction] {
+  override def chainId: BigInt = ???
+
+  override def signatureFromBytes(bytes65: ByteString): Option[ECDSASignature] = ???
+
+  override def getRAWSignature(signedTransaction: SignedTransaction): Either[SignerError, ECDSASignature] = ???
+
+  override def payloadToSign(tx: LegacyTransaction): Either[SignerError, Array[Byte]] = ???
+
+  override def calculateSender(signedTransaction: SignedTransaction): Option[Address] = ???
+}

src/main/scala/io/iohk/ethereum/signer/TransactionSigner.scala

@@ -0,0 +1,35 @@
+package io.iohk.ethereum.signer
+
+import akka.util.ByteString
+
+import io.iohk.ethereum.crypto.ECDSASignature
+import io.iohk.ethereum.domain.Address
+import io.iohk.ethereum.domain.SignedTransaction
+import io.iohk.ethereum.domain.Transaction
+import io.iohk.ethereum.utils.BlockchainConfig
+
+trait TransactionSigner[T <: Transaction] {
+  def chainId: BigInt
+  def signatureFromBytes(bytes65: ByteString): Option[ECDSASignature]
+  def getRAWSignature(signedTransaction: SignedTransaction): Either[SignerError, ECDSASignature]
+  def payloadToSign(transaction: T): Either[SignerError, Array[Byte]]
+  def calculateSender(signedTransaction: SignedTransaction): Option[Address]
+}
+
+object TransactionSigner {
+
+  /** @param blockchainConfig
+    * @param blockNumber
+    * @return the proper signer corresponding to the block number
+    */
+  def get(blockchainConfig: BlockchainConfig, blockNumber: BigInt): Signer =
+    // TODO should we explicitely handle berlin fork ?
+    if (blockNumber >= blockchainConfig.forkBlockNumbers.magnetoBlockNumber) {
+      new EIP2930Signer(blockchainConfig.chainId)
+    } else if (blockNumber >= blockchainConfig.forkBlockNumbers.eip155BlockNumber) {
+      new EIP155Signer(blockchainConfig.chainId)
+    } else {
+      new HomesteadSigner
+    }
+
+}