add BlockSigners reader

contracts/smcReader.go

@@ -0,0 +1,96 @@
+package contracts
+
+import (
+	"fmt"
+	"strings"
+	"math/big"
+	"time"
+
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/contracts/blocksigner/contract"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+var (
+	slotBlockSignerMapping = map[string]uint64{
+		"getSigners": 0,
+	}
+	ParsedBlockSignerABI, _ = abi.JSON(strings.NewReader(contract.BlockSignerABI))
+)
+
+///////////////////////////////////////
+//////     BlockSigner SMC  ///////////
+///////////////////////////////////////
+func GetSigners(statedb *state.StateDB, parsed abi.ABI, block *types.Block) ([]common.Address) {
+	methodName := "getSigners"
+	fmt.Printf("---%s---\n", methodName)
+	start := time.Now()
+	signers := getSigners(parsed, statedb, common.HexToAddress(common.BlockSigners), methodName, block.Hash())
+	elapsed := time.Since(start)
+	fmt.Printf("Execution time: %s\n", elapsed)
+	return signers
+}
+
+func getSigners(parsed abi.ABI, statedb *state.StateDB, address common.Address, methodName string, input ...common.Hash) ([]common.Address) {
+	keys := getKeyStorage(statedb, address, parsed, methodName, input...)
+	rets := []common.Address{}
+	ret := common.Address{}
+	for _, key := range keys {
+		value := statedb.GetState(address, key)
+		method := parsed.Methods[methodName]
+		switch method.Outputs[0].Type.T {
+		case abi.StringTy:
+			//do nothing - output can't be string in this method
+			//ret = string(value.Bytes())
+		default:
+			parsed.Unpack(&ret, methodName, value.Bytes())
+			rets = append(rets, ret)
+		}
+	}
+	return rets
+}
+
+func getKeyStorage(statedb *state.StateDB, address common.Address, parsed abi.ABI, methodName string, input ...common.Hash) ([]common.Hash) {
+	method, ok := parsed.Methods[methodName]
+	slot := slotBlockSignerMapping[methodName]
+	keys := []common.Hash{}
+
+	// do not support function call
+	if ok && len(method.Inputs) <= 1 || len(method.Outputs) == 1 {
+		if len(method.Inputs) == 0 {
+			keys = append(keys, getKey(slot))
+		} else {
+			// support first input
+			keyArrSlot := mapLocAtKey(input[0], slot)
+			arrSlot := statedb.GetState(address, keyArrSlot)
+			arrLength := arrSlot.Big().Uint64()
+			for i := uint64(0); i < arrLength; i++ {
+				valueHash := arrDynamicLocAtElement(keyArrSlot, i, 1)
+				keys = append(keys, valueHash)
+			}
+		}
+	}
+	return keys
+}
+
+func getKey(slot uint64) common.Hash {
+	updatedKey := common.BigToHash(new(big.Int).SetUint64(slot))
+	return updatedKey
+}
+
+func mapLocAtKey(key common.Hash, slot uint64) common.Hash {
+	slotHash := common.BigToHash(new(big.Int).SetUint64(slot))
+	updatedKey := crypto.Keccak256Hash(key.Bytes(), slotHash.Bytes())
+	return updatedKey
+}
+
+func arrDynamicLocAtElement(slotHash common.Hash, index uint64, elementSize uint64) common.Hash {
+	slotKecBig := crypto.Keccak256Hash(slotHash.Bytes()).Big()
+	//arrBig = slotKecBig + index * elementSize
+	arrBig := slotKecBig.Add(slotKecBig, new(big.Int).SetUint64(index * elementSize))
+	arrHash := common.BigToHash(arrBig)
+	return arrHash
+}