From 9de0a7a2d63b2fc68751fc556c05ebd5cd35c4d8 Mon Sep 17 00:00:00 2001
From: Mason Fischer <mason@kissr.co>
Date: Wed, 13 May 2020 12:48:08 -0400
Subject: [PATCH] Add state_manager

---
 core/vm/state_manager.go | 58 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 core/vm/state_manager.go

diff --git a/core/vm/state_manager.go b/core/vm/state_manager.go
new file mode 100644
index 0000000000..8634200ba7
--- /dev/null
+++ b/core/vm/state_manager.go
@@ -0,0 +1,58 @@
+package vm
+
+import (
+  "os"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+var (
+  StateManagerAddress = common.HexToAddress(os.Getenv("STATE_MANAGER_ADDRESS"))
+)
+
+type ovmOperation func(*EVM, *Contract, []byte) ([]byte, error)
+type methodId [4]byte
+
+var funcs = map[string]ovmOperation{
+	"getStorage(address,bytes32)": getStorage,
+	"setStorage(address,bytes32,bytes32)":  setStorage,
+}
+var methodIds map[[4]byte]ovmOperation
+var executionMangerBytecode []byte
+
+
+func init() {
+	methodIds = make(map[[4]byte]ovmOperation, len(funcs))
+	for methodSignature, f := range funcs {
+    methodIds[MethodSignatureToMethodId(methodSignature)] = f
+	}
+}
+
+
+func MethodSignatureToMethodId(methodSignature string) [4]byte {
+	var methodId [4]byte
+	copy(methodId[:], crypto.Keccak256([]byte(methodSignature)))
+	return methodId
+}
+
+
+func callStateManager(input []byte, evm *EVM, contract *Contract) (ret []byte, err error) {
+	var methodId [4]byte
+	copy(methodId[:], input[:4])
+	ret, err = methodIds[methodId](evm, contract, input)
+	return ret, err
+}
+
+func setStorage(evm *EVM, contract *Contract, input []byte) (ret []byte, err error) {
+  key := common.BytesToHash(input[4:36])
+	val := common.BytesToHash(input[36:68])
+	evm.StateDB.SetState(contract.Address(), key, val)
+  return nil, nil
+}
+func getStorage(evm *EVM, contract *Contract, input []byte) (ret []byte, err error) {
+  key := common.BytesToHash(input[4:36])
+	val := evm.StateDB.GetState(contract.Address(), key)
+	return val.Bytes(), nil
+  return []byte{}, nil
+}