The core protocol of WoopChain
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woop/core/state_transition.go

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// Copyright 2014 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 core
import (
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/rlp"
"github.com/harmony-one/harmony/core/types"
"github.com/harmony-one/harmony/core/vm"
"github.com/harmony-one/harmony/internal/utils"
"github.com/harmony-one/harmony/numeric"
"github.com/harmony-one/harmony/shard"
stakingTypes "github.com/harmony-one/harmony/staking/types"
"github.com/pkg/errors"
)
var (
errInvalidSigner = errors.New("invalid signer for staking transaction")
errInsufficientBalanceForGas = errors.New("insufficient balance to pay for gas")
errInsufficientBalanceForStake = errors.New("insufficient balance to stake")
errValidatorExist = errors.New("staking validator already exists")
errValidatorNotExist = errors.New("staking validator does not exist")
errNoDelegationToUndelegate = errors.New("no delegation to undelegate")
errCommissionRateChangeTooFast = errors.New("change on commission rate can not be more than max change rate within the same epoch")
errCommissionRateChangeTooHigh = errors.New("commission rate can not be higher than maximum commission rate")
errCommissionRateChangeTooLowT = errors.New("commission rate can not be lower than min rate of ")
errNoRewardsToCollect = errors.New("no rewards to collect")
errNegativeAmount = errors.New("amount can not be negative")
errDupIdentity = errors.New("validator identity exists")
errDupBlsKey = errors.New("BLS key exists")
)
/*
StateTransition is the State Transitioning Model which is described as follows:
A state transition is a change made when a transaction is applied to the current world state
The state transitioning model does all the necessary work to work out a valid new state root.
1) Nonce handling
2) Pre pay gas
3) Create a new state object if the recipient is \0*32
4) Value transfer
== If contract creation ==
4a) Attempt to run transaction data
4b) If valid, use result as code for the new state object
== end ==
5) Run Script section
6) Derive new state root
*/
type StateTransition struct {
gp *GasPool
msg Message
gas uint64
gasPrice *big.Int
initialGas uint64
value *big.Int
data []byte
state vm.StateDB
evm *vm.EVM
bc ChainContext
}
// Message represents a message sent to a contract.
type Message interface {
From() common.Address
//FromFrontier() (common.Address, error)
To() *common.Address
GasPrice() *big.Int
Gas() uint64
Value() *big.Int
Nonce() uint64
CheckNonce() bool
Data() []byte
Type() types.TransactionType
BlockNum() *big.Int
}
// ExecutionResult is the return value from a transaction committed to the DB
type ExecutionResult struct {
ReturnData []byte
UsedGas uint64
VMErr error
}
// Unwrap returns the internal evm error which allows us for further
// analysis outside.
func (result *ExecutionResult) Unwrap() error {
return result.VMErr
}
// Failed returns the indicator whether the execution is successful or not
func (result *ExecutionResult) Failed() bool { return result.VMErr != nil }
// Return is a helper function to help caller distinguish between revert reason
// and function return. Return returns the data after execution if no error occurs.
func (result *ExecutionResult) Return() []byte {
if result.VMErr != nil {
return nil
}
return common.CopyBytes(result.ReturnData)
}
// Revert returns the concrete revert reason if the execution is aborted by `REVERT`
// opcode. Note the reason can be nil if no data supplied with revert opcode.
func (result *ExecutionResult) Revert() []byte {
if result.VMErr != vm.ErrExecutionReverted {
return nil
}
return common.CopyBytes(result.ReturnData)
}
// NewStateTransition initialises and returns a new state transition object.
func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool, bc ChainContext) *StateTransition {
return &StateTransition{
gp: gp,
evm: evm,
msg: msg,
gasPrice: msg.GasPrice(),
value: msg.Value(),
data: msg.Data(),
state: evm.StateDB,
bc: bc,
}
}
// ApplyMessage computes the new state by applying the given message
// against the old state within the environment.
//
// ApplyMessage returns the bytes returned by any EVM execution (if it took place),
// the gas used (which includes gas refunds) and an error if it failed. An error always
// indicates a core error meaning that the message would always fail for that particular
// state and would never be accepted within a block.
func ApplyMessage(evm *vm.EVM, msg Message, gp *GasPool) (ExecutionResult, error) {
return NewStateTransition(evm, msg, gp, nil).TransitionDb()
}
// ApplyStakingMessage computes the new state for staking message
func ApplyStakingMessage(evm *vm.EVM, msg Message, gp *GasPool, bc ChainContext) (uint64, error) {
return NewStateTransition(evm, msg, gp, bc).StakingTransitionDb()
}
// to returns the recipient of the message.
func (st *StateTransition) to() common.Address {
if st.msg == nil || st.msg.To() == nil /* contract creation */ {
return common.Address{}
}
return *st.msg.To()
}
func (st *StateTransition) useGas(amount uint64) error {
if st.gas < amount {
return vm.ErrOutOfGas
}
st.gas -= amount
return nil
}
func (st *StateTransition) buyGas() error {
mgval := new(big.Int).Mul(new(big.Int).SetUint64(st.msg.Gas()), st.gasPrice)
if have := st.state.GetBalance(st.msg.From()); have.Cmp(mgval) < 0 {
return errors.Wrapf(
errInsufficientBalanceForGas,
"had: %s but need: %s", have.String(), mgval.String(),
)
}
if err := st.gp.SubGas(st.msg.Gas()); err != nil {
return err
}
st.gas += st.msg.Gas()
st.initialGas = st.msg.Gas()
st.state.SubBalance(st.msg.From(), mgval)
return nil
}
func (st *StateTransition) preCheck() error {
// Make sure this transaction's nonce is correct.
if st.msg.CheckNonce() {
nonce := st.state.GetNonce(st.msg.From())
if nonce < st.msg.Nonce() {
return ErrNonceTooHigh
} else if nonce > st.msg.Nonce() {
return ErrNonceTooLow
}
}
return st.buyGas()
}
// TransitionDb will transition the state by applying the current message and
// returning the result including the used gas. It returns an error if failed.
// An error indicates a consensus issue.
func (st *StateTransition) TransitionDb() (ExecutionResult, error) {
if err := st.preCheck(); err != nil {
return ExecutionResult{}, err
}
msg := st.msg
sender := vm.AccountRef(msg.From())
homestead := st.evm.ChainConfig().IsS3(st.evm.EpochNumber) // s3 includes homestead
istanbul := st.evm.ChainConfig().IsIstanbul(st.evm.EpochNumber)
contractCreation := msg.To() == nil
// Pay intrinsic gas
gas, err := vm.IntrinsicGas(st.data, contractCreation, homestead, istanbul, false)
if err != nil {
return ExecutionResult{}, err
}
if err = st.useGas(gas); err != nil {
return ExecutionResult{}, fmt.Errorf("%w: have %d, want %d", ErrIntrinsicGas, st.gas, gas)
}
evm := st.evm
var ret []byte
// All VM errors are valid except for insufficient balance, therefore returned separately
var vmErr error
if contractCreation {
ret, _, st.gas, vmErr = evm.Create(sender, st.data, st.gas, st.value)
} else {
// Increment the nonce for the next transaction
st.state.SetNonce(msg.From(), st.state.GetNonce(sender.Address())+1)
ret, st.gas, vmErr = evm.Call(sender, st.to(), st.data, st.gas, st.value)
}
if vmErr != nil {
utils.Logger().Debug().Err(vmErr).Msg("VM returned with error")
// The only possible consensus-error would be if there wasn't
// sufficient balance to make the transfer happen. The first
// balance transfer may never fail.
if vmErr == vm.ErrInsufficientBalance {
return ExecutionResult{}, vmErr
}
}
st.refundGas()
st.collectGas()
return ExecutionResult{
ReturnData: ret,
UsedGas: st.gasUsed(),
VMErr: vmErr,
}, err
}
func (st *StateTransition) refundGas() {
// Apply refund counter, capped to half of the used gas.
refund := st.gasUsed() / 2
if refund > st.state.GetRefund() {
refund = st.state.GetRefund()
}
st.gas += refund
// Return ETH for remaining gas, exchanged at the original rate.
remaining := new(big.Int).Mul(new(big.Int).SetUint64(st.gas), st.gasPrice)
st.state.AddBalance(st.msg.From(), remaining)
// Also return remaining gas to the block gas counter so it is
// available for the next transaction.
st.gp.AddGas(st.gas)
}
func (st *StateTransition) collectGas() {
if config := st.evm.ChainConfig(); !config.IsStaking(st.evm.EpochNumber) {
// Before staking epoch, add the fees to the block producer
txFee := new(big.Int).Mul(
new(big.Int).SetUint64(st.gasUsed()),
st.gasPrice,
)
st.state.AddBalance(st.evm.Coinbase, txFee)
} else if feeCollectors := shard.Schedule.InstanceForEpoch(
st.evm.EpochNumber,
).FeeCollectors(); len(feeCollectors) > 0 {
// The caller must ensure that the feeCollectors are accurately set
// at the appropriate epochs
txFee := numeric.NewDecFromBigInt(
new(big.Int).Mul(
new(big.Int).SetUint64(st.gasUsed()),
st.gasPrice,
),
)
for address, percent := range feeCollectors {
collectedFee := percent.Mul(txFee)
st.state.AddBalance(address, collectedFee.TruncateInt())
}
}
}
// gasUsed returns the amount of gas used up by the state transition.
func (st *StateTransition) gasUsed() uint64 {
return st.initialGas - st.gas
}
// StakingTransitionDb will transition the state by applying the staking message and
// returning the result including the used gas. It returns an error if failed.
// It is used for staking transaction only
func (st *StateTransition) StakingTransitionDb() (usedGas uint64, err error) {
if err = st.preCheck(); err != nil {
return 0, err
}
msg := st.msg
sender := vm.AccountRef(msg.From())
homestead := st.evm.ChainConfig().IsS3(st.evm.EpochNumber) // s3 includes homestead
istanbul := st.evm.ChainConfig().IsIstanbul(st.evm.EpochNumber)
// Pay intrinsic gas
gas, err := vm.IntrinsicGas(st.data, false, homestead, istanbul, msg.Type() == types.StakeCreateVal)
if err != nil {
return 0, err
}
if err = st.useGas(gas); err != nil {
return 0, err
}
// Increment the nonce for the next transaction
st.state.SetNonce(msg.From(), st.state.GetNonce(sender.Address())+1)
// from worker.go, we get here with shardID == BeaconChainShardID
// from node_handler.go, via blockchain.go => it is checked that block shard == node shard
// same via consensus
// so only possible to reach here if shardID == BeaconChainShardID (no need to check further)
switch msg.Type() {
case types.StakeCreateVal:
stkMsg := &stakingTypes.CreateValidator{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().
Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.ValidatorAddress {
return 0, errInvalidSigner
}
err = st.evm.CreateValidator(st.evm.StateDB, nil, stkMsg)
case types.StakeEditVal:
stkMsg := &stakingTypes.EditValidator{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().
Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.ValidatorAddress {
return 0, errInvalidSigner
}
err = st.evm.EditValidator(st.evm.StateDB, nil, stkMsg)
case types.Delegate:
stkMsg := &stakingTypes.Delegate{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.DelegatorAddress {
return 0, errInvalidSigner
}
err = st.evm.Delegate(st.evm.StateDB, nil, stkMsg)
case types.Undelegate:
stkMsg := &stakingTypes.Undelegate{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.DelegatorAddress {
return 0, errInvalidSigner
}
err = st.evm.Undelegate(st.evm.StateDB, nil, stkMsg)
case types.CollectRewards:
stkMsg := &stakingTypes.CollectRewards{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.DelegatorAddress {
return 0, errInvalidSigner
}
err = st.evm.CollectRewards(st.evm.StateDB, nil, stkMsg)
default:
return 0, stakingTypes.ErrInvalidStakingKind
}
st.refundGas()
st.collectGas()
return st.gasUsed(), err
}