Moved execution from vm to chain.

This moves call and create to the specified environments. Vms are no
longer re-used. Vm uses environment's Call(Code) and Create in order to
execute new contracts or transfer value between accounts.

State transition now uses the same mechanism described above.

3 files changed, 112 insertions, 108 deletions

diff --git a/chain/execution.go b/chain/execution.go
new file mode 100644
index 000000000..932ffa868
--- /dev/null
+++ b/chain/execution.go
@@ -0,0 +1,80 @@
+package chain
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/ethutil"
+	"github.com/ethereum/go-ethereum/state"
+	"github.com/ethereum/go-ethereum/vm"
+)
+
+type Execution struct {
+	vm                vm.VirtualMachine
+	address, input    []byte
+	Gas, price, value *big.Int
+	object            *state.StateObject
+	SkipTransfer      bool
+}
+
+func NewExecution(vm vm.VirtualMachine, address, input []byte, gas, gasPrice, value *big.Int) *Execution {
+	return &Execution{vm: vm, address: address, input: input, Gas: gas, price: gasPrice, value: value}
+}
+
+func (self *Execution) Addr() []byte {
+	return self.address
+}
+
+func (self *Execution) Call(codeAddr []byte, caller vm.ClosureRef) ([]byte, error) {
+	// Retrieve the executing code
+	code := self.vm.Env().State().GetCode(codeAddr)
+
+	return self.exec(code, codeAddr, caller)
+}
+
+func (self *Execution) exec(code, caddr []byte, caller vm.ClosureRef) (ret []byte, err error) {
+	env := self.vm.Env()
+
+	chainlogger.Debugf("pre state %x\n", env.State().Root())
+	snapshot := env.State().Copy()
+	defer func() {
+		if vm.IsDepthErr(err) || vm.IsOOGErr(err) {
+			env.State().Set(snapshot)
+		}
+		chainlogger.Debugf("post state %x\n", env.State().Root())
+	}()
+
+	from, to := env.State().GetStateObject(caller.Address()), env.State().GetOrNewStateObject(self.address)
+	// Skipping transfer is used on testing for the initial call
+	if !self.SkipTransfer {
+		err = env.Transfer(from, to, self.value)
+	}
+
+	if err != nil {
+		caller.ReturnGas(self.Gas, self.price)
+
+		err = fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, from.Balance)
+	} else {
+		self.object = to
+		// Pre-compiled contracts (address.go) 1, 2 & 3.
+		naddr := ethutil.BigD(caddr).Uint64()
+		if p := vm.Precompiled[naddr]; p != nil {
+			if self.Gas.Cmp(p.Gas) >= 0 {
+				ret = p.Call(self.input)
+				self.vm.Printf("NATIVE_FUNC(%x) => %x", naddr, ret)
+				self.vm.Endl()
+			}
+		} else {
+			ret, err = self.vm.Run(to, caller, code, self.value, self.Gas, self.price, self.input)
+		}
+	}
+
+	return
+}
+
+func (self *Execution) Create(caller vm.ClosureRef) (ret []byte, err error, account *state.StateObject) {
+	ret, err = self.exec(self.input, nil, caller)
+	account = self.vm.Env().State().GetStateObject(self.address)
+
+	return
+}
diff --git a/chain/state_transition.go b/chain/state_transition.go
index 8f7b55cd4..b2ba4f22a 100644
--- a/chain/state_transition.go
+++ b/chain/state_transition.go
@@ -169,120 +169,21 @@ func (self *StateTransition) TransitionState() (err error) {
 		return
 	}
 
-	if sender.Balance().Cmp(self.value) < 0 {
-		return fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, sender.Balance)
-	}
-
-	var snapshot *state.State
-	// If the receiver is nil it's a contract (\0*32).
+	var ret []byte
+	vmenv := NewEnv(self.state, self.tx, self.block)
+	var ref vm.ClosureRef
 	if tx.CreatesContract() {
-		// Subtract the (irreversible) amount from the senders account
-		sender.SubAmount(self.value)
+		self.rec = MakeContract(tx, self.state)
 
-		snapshot = self.state.Copy()
-
-		// Create a new state object for the contract
-		receiver = MakeContract(tx, self.state)
-		self.rec = receiver
-		if receiver == nil {
-			return fmt.Errorf("Unable to create contract")
-		}
-
-		// Add the amount to receivers account which should conclude this transaction
-		receiver.AddAmount(self.value)
+		ret, err, ref = vmenv.Create(sender, receiver.Address(), self.tx.Data, self.gas, self.gasPrice, self.value)
+		ref.SetCode(ret)
 	} else {
-		receiver = self.Receiver()
-
-		// Subtract the amount from the senders account
-		sender.SubAmount(self.value)
-		// Add the amount to receivers account which should conclude this transaction
-		receiver.AddAmount(self.value)
-
-		snapshot = self.state.Copy()
+		ret, err = vmenv.Call(self.Sender(), self.Receiver().Address(), self.tx.Data, self.gas, self.gasPrice, self.value)
 	}
-
-	msg := self.state.Manifest().AddMessage(&state.Message{
-		To: receiver.Address(), From: sender.Address(),
-		Input:  self.tx.Data,
-		Origin: sender.Address(),
-		Block:  self.block.Hash(), Timestamp: self.block.Time, Coinbase: self.block.Coinbase, Number: self.block.Number,
-		Value: self.value,
-	})
-
-	// Process the init code and create 'valid' contract
-	if types.IsContractAddr(self.receiver) {
-		// Evaluate the initialization script
-		// and use the return value as the
-		// script section for the state object.
-		self.data = nil
-
-		code, evmerr := self.Eval(msg, receiver.Init(), receiver)
-		if evmerr != nil {
-			self.state.Set(snapshot)
-
-			statelogger.Debugf("Error during init execution %v", evmerr)
-		}
-
-		receiver.Code = code
-		msg.Output = code
-	} else {
-		if len(receiver.Code) > 0 {
-			ret, evmerr := self.Eval(msg, receiver.Code, receiver)
-			if evmerr != nil {
-				self.state.Set(snapshot)
-
-				statelogger.Debugf("Error during code execution %v", evmerr)
-			}
-
-			msg.Output = ret
-		}
+	if err != nil {
+		statelogger.Debugln(err)
 	}
 
-	/*
-	* XXX The following _should_ replace the above transaction
-	* execution (also for regular calls. Will replace / test next
-	* phase
-	 */
-	/*
-		// Execute transaction
-		if tx.CreatesContract() {
-			self.rec = MakeContract(tx, self.state)
-		}
-
-		address := self.Receiver().Address()
-		evm := vm.New(NewEnv(state, self.tx, self.block), vm.DebugVmTy)
-		exe := NewExecution(evm, address, self.tx.Data, self.gas, self.gas.Price, self.tx.Value)
-		ret, err := msg.Exec(address, self.Sender())
-		if err != nil {
-			statelogger.Debugln(err)
-		} else {
-			if tx.CreatesContract() {
-				self.Receiver().Code = ret
-			}
-			msg.Output = ret
-		}
-	*/
-
-	// Add default LOG. Default = big(sender.addr) + 1
-	//addr := ethutil.BigD(receiver.Address())
-	//self.state.AddLog(&state.Log{ethutil.U256(addr.Add(addr, ethutil.Big1)).Bytes(), [][]byte{sender.Address()}, nil})
-
-	return
-}
-
-func (self *StateTransition) Eval(msg *state.Message, script []byte, context *state.StateObject) (ret []byte, err error) {
-	var (
-		transactor    = self.Sender()
-		state         = self.state
-		env           = NewEnv(state, self.tx, self.block)
-		callerClosure = vm.NewClosure(msg, transactor, context, script, self.gas, self.gasPrice)
-	)
-
-	evm := vm.New(env, vm.DebugVmTy)
-	// TMP this will change in the refactor
-	callerClosure.SetExecution(vm.NewExecution(evm, nil, nil, nil, nil, self.tx.Value))
-	ret, _, err = callerClosure.Call(evm, self.tx.Data)
-
 	return
 }
 
diff --git a/chain/vm_env.go b/chain/vm_env.go
index c1911ff51..c2428c234 100644
--- a/chain/vm_env.go
+++ b/chain/vm_env.go
@@ -12,6 +12,7 @@ type VMEnv struct {
 	state *state.State
 	block *types.Block
 	tx    *types.Transaction
+	depth int
 }
 
 func NewEnv(state *state.State, tx *types.Transaction, block *types.Block) *VMEnv {
@@ -32,9 +33,31 @@ func (self *VMEnv) BlockHash() []byte     { return self.block.Hash() }
 func (self *VMEnv) Value() *big.Int       { return self.tx.Value }
 func (self *VMEnv) State() *state.State   { return self.state }
 func (self *VMEnv) GasLimit() *big.Int    { return self.block.GasLimit }
+func (self *VMEnv) Depth() int            { return self.depth }
+func (self *VMEnv) SetDepth(i int)        { self.depth = i }
 func (self *VMEnv) AddLog(log *state.Log) {
 	self.state.AddLog(log)
 }
 func (self *VMEnv) Transfer(from, to vm.Account, amount *big.Int) error {
 	return vm.Transfer(from, to, amount)
 }
+
+func (self *VMEnv) vm(addr, data []byte, gas, price, value *big.Int) *Execution {
+	evm := vm.New(self, vm.DebugVmTy)
+
+	return NewExecution(evm, addr, data, gas, price, value)
+}
+
+func (self *VMEnv) Call(me vm.ClosureRef, addr, data []byte, gas, price, value *big.Int) ([]byte, error) {
+	exe := self.vm(addr, data, gas, price, value)
+	return exe.Call(addr, me)
+}
+func (self *VMEnv) CallCode(me vm.ClosureRef, addr, data []byte, gas, price, value *big.Int) ([]byte, error) {
+	exe := self.vm(me.Address(), data, gas, price, value)
+	return exe.Call(addr, me)
+}
+
+func (self *VMEnv) Create(me vm.ClosureRef, addr, data []byte, gas, price, value *big.Int) ([]byte, error, vm.ClosureRef) {
+	exe := self.vm(addr, data, gas, price, value)
+	return exe.Create(me)
+}