1 files changed, 271 insertions, 0 deletions
diff --git a/light/vm_env.go b/light/vm_env.go
new file mode 100644
index 000000000..0f4b90908
--- /dev/null
+++ b/light/vm_env.go
@@ -0,0 +1,271 @@
+// Copyright 2015 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 light
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/crypto"
+	"golang.org/x/net/context"
+)
+
+// VMEnv is the light client version of the vm execution environment.
+// Unlike other structures, VMEnv holds a context that is applied by state
+// retrieval requests through the entire execution. If any state operation
+// returns an error, the execution fails.
+type VMEnv struct {
+	vm.Environment
+	ctx         context.Context
+	chainConfig *core.ChainConfig
+	evm         *vm.EVM
+	state       *VMState
+	header      *types.Header
+	msg         core.Message
+	depth       int
+	chain       *LightChain
+	err         error
+}
+
+// NewEnv creates a new execution environment based on an ODR capable light state
+func NewEnv(ctx context.Context, state *LightState, chainConfig *core.ChainConfig, chain *LightChain, msg core.Message, header *types.Header, cfg vm.Config) *VMEnv {
+	env := &VMEnv{
+		chainConfig: chainConfig,
+		chain:       chain,
+		header:      header,
+		msg:         msg,
+	}
+	env.state = &VMState{ctx: ctx, state: state, env: env}
+
+	env.evm = vm.New(env, cfg)
+	return env
+}
+
+func (self *VMEnv) RuleSet() vm.RuleSet      { return self.chainConfig }
+func (self *VMEnv) Vm() vm.Vm                { return self.evm }
+func (self *VMEnv) Origin() common.Address   { f, _ := self.msg.From(); return f }
+func (self *VMEnv) BlockNumber() *big.Int    { return self.header.Number }
+func (self *VMEnv) Coinbase() common.Address { return self.header.Coinbase }
+func (self *VMEnv) Time() *big.Int           { return self.header.Time }
+func (self *VMEnv) Difficulty() *big.Int     { return self.header.Difficulty }
+func (self *VMEnv) GasLimit() *big.Int       { return self.header.GasLimit }
+func (self *VMEnv) Db() vm.Database          { return self.state }
+func (self *VMEnv) Depth() int               { return self.depth }
+func (self *VMEnv) SetDepth(i int)           { self.depth = i }
+func (self *VMEnv) GetHash(n uint64) common.Hash {
+	for header := self.chain.GetHeader(self.header.ParentHash, self.header.Number.Uint64()-1); header != nil; header = self.chain.GetHeader(header.ParentHash, header.Number.Uint64()-1) {
+		if header.GetNumberU64() == n {
+			return header.Hash()
+		}
+	}
+
+	return common.Hash{}
+}
+
+func (self *VMEnv) AddLog(log *vm.Log) {
+	//self.state.AddLog(log)
+}
+func (self *VMEnv) CanTransfer(from common.Address, balance *big.Int) bool {
+	return self.state.GetBalance(from).Cmp(balance) >= 0
+}
+
+func (self *VMEnv) SnapshotDatabase() int {
+	return self.state.SnapshotDatabase()
+}
+
+func (self *VMEnv) RevertToSnapshot(idx int) {
+	self.state.RevertToSnapshot(idx)
+}
+
+func (self *VMEnv) Transfer(from, to vm.Account, amount *big.Int) {
+	core.Transfer(from, to, amount)
+}
+
+func (self *VMEnv) Call(me vm.ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error) {
+	return core.Call(self, me, addr, data, gas, price, value)
+}
+func (self *VMEnv) CallCode(me vm.ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error) {
+	return core.CallCode(self, me, addr, data, gas, price, value)
+}
+
+func (self *VMEnv) DelegateCall(me vm.ContractRef, addr common.Address, data []byte, gas, price *big.Int) ([]byte, error) {
+	return core.DelegateCall(self, me, addr, data, gas, price)
+}
+
+func (self *VMEnv) Create(me vm.ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error) {
+	return core.Create(self, me, data, gas, price, value)
+}
+
+// Error returns the error (if any) that happened during execution.
+func (self *VMEnv) Error() error {
+	return self.err
+}
+
+// VMState is a wrapper for the light state that holds the actual context and
+// passes it to any state operation that requires it.
+type VMState struct {
+	vm.Database
+	ctx       context.Context
+	state     *LightState
+	snapshots []*LightState
+	env       *VMEnv
+}
+
+// errHandler handles and stores any state error that happens during execution.
+func (s *VMState) errHandler(err error) {
+	if err != nil && s.env.err == nil {
+		s.env.err = err
+	}
+}
+
+func (self *VMState) SnapshotDatabase() int {
+	self.snapshots = append(self.snapshots, self.state.Copy())
+	return len(self.snapshots) - 1
+}
+
+func (self *VMState) RevertToSnapshot(idx int) {
+	self.state.Set(self.snapshots[idx])
+	self.snapshots = self.snapshots[:idx]
+}
+
+// GetAccount returns the account object of the given account or nil if the
+// account does not exist
+func (s *VMState) GetAccount(addr common.Address) vm.Account {
+	so, err := s.state.GetStateObject(s.ctx, addr)
+	s.errHandler(err)
+	if err != nil {
+		// return a dummy state object to avoid panics
+		so = s.state.newStateObject(addr)
+	}
+	return so
+}
+
+// CreateAccount creates creates a new account object and takes ownership.
+func (s *VMState) CreateAccount(addr common.Address) vm.Account {
+	so, err := s.state.CreateStateObject(s.ctx, addr)
+	s.errHandler(err)
+	if err != nil {
+		// return a dummy state object to avoid panics
+		so = s.state.newStateObject(addr)
+	}
+	return so
+}
+
+// AddBalance adds the given amount to the balance of the specified account
+func (s *VMState) AddBalance(addr common.Address, amount *big.Int) {
+	err := s.state.AddBalance(s.ctx, addr, amount)
+	s.errHandler(err)
+}
+
+// GetBalance retrieves the balance from the given address or 0 if the account does
+// not exist
+func (s *VMState) GetBalance(addr common.Address) *big.Int {
+	res, err := s.state.GetBalance(s.ctx, addr)
+	s.errHandler(err)
+	return res
+}
+
+// GetNonce returns the nonce at the given address or 0 if the account does
+// not exist
+func (s *VMState) GetNonce(addr common.Address) uint64 {
+	res, err := s.state.GetNonce(s.ctx, addr)
+	s.errHandler(err)
+	return res
+}
+
+// SetNonce sets the nonce of the specified account
+func (s *VMState) SetNonce(addr common.Address, nonce uint64) {
+	err := s.state.SetNonce(s.ctx, addr, nonce)
+	s.errHandler(err)
+}
+
+// GetCode returns the contract code at the given address or nil if the account
+// does not exist
+func (s *VMState) GetCode(addr common.Address) []byte {
+	res, err := s.state.GetCode(s.ctx, addr)
+	s.errHandler(err)
+	return res
+}
+
+// GetCodeHash returns the contract code hash at the given address
+func (s *VMState) GetCodeHash(addr common.Address) common.Hash {
+	res, err := s.state.GetCode(s.ctx, addr)
+	s.errHandler(err)
+	return crypto.Keccak256Hash(res)
+}
+
+// GetCodeSize returns the contract code size at the given address
+func (s *VMState) GetCodeSize(addr common.Address) int {
+	res, err := s.state.GetCode(s.ctx, addr)
+	s.errHandler(err)
+	return len(res)
+}
+
+// SetCode sets the contract code at the specified account
+func (s *VMState) SetCode(addr common.Address, code []byte) {
+	err := s.state.SetCode(s.ctx, addr, code)
+	s.errHandler(err)
+}
+
+// AddRefund adds an amount to the refund value collected during a vm execution
+func (s *VMState) AddRefund(gas *big.Int) {
+	s.state.AddRefund(gas)
+}
+
+// GetRefund returns the refund value collected during a vm execution
+func (s *VMState) GetRefund() *big.Int {
+	return s.state.GetRefund()
+}
+
+// GetState returns the contract storage value at storage address b from the
+// contract address a or common.Hash{} if the account does not exist
+func (s *VMState) GetState(a common.Address, b common.Hash) common.Hash {
+	res, err := s.state.GetState(s.ctx, a, b)
+	s.errHandler(err)
+	return res
+}
+
+// SetState sets the storage value at storage address key of the account addr
+func (s *VMState) SetState(addr common.Address, key common.Hash, value common.Hash) {
+	err := s.state.SetState(s.ctx, addr, key, value)
+	s.errHandler(err)
+}
+
+// Suicide marks an account to be removed and clears its balance
+func (s *VMState) Suicide(addr common.Address) bool {
+	res, err := s.state.Suicide(s.ctx, addr)
+	s.errHandler(err)
+	return res
+}
+
+// Exist returns true if an account exists at the given address
+func (s *VMState) Exist(addr common.Address) bool {
+	res, err := s.state.HasAccount(s.ctx, addr)
+	s.errHandler(err)
+	return res
+}
+
+// HasSuicided returns true if the given account has been marked for deletion
+// or false if the account does not exist
+func (s *VMState) HasSuicided(addr common.Address) bool {
+	res, err := s.state.HasSuicided(s.ctx, addr)
+	s.errHandler(err)
+	return res
+}