path: root/core/execution.go

package core

import (
    "math/big"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/vm"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/params"
)

type Execution struct {
    env     vm.Environment
    address *common.Address
    input   []byte
    evm     vm.VirtualMachine

    Gas, price, value *big.Int
}

func NewExecution(env vm.Environment, address *common.Address, input []byte, gas, gasPrice, value *big.Int) *Execution {
    exe := &Execution{env: env, address: address, input: input, Gas: gas, price: gasPrice, value: value}
    exe.evm = vm.NewVm(env)
    return exe
}

func (self *Execution) Call(codeAddr common.Address, caller vm.ContextRef) ([]byte, error) {
    // Retrieve the executing code
    code := self.env.State().GetCode(codeAddr)

    return self.exec(&codeAddr, code, caller)
}

func (self *Execution) Create(caller vm.ContextRef) (ret []byte, err error, account *state.StateObject) {
    // Input must be nil for create
    code := self.input
    self.input = nil
    ret, err = self.exec(nil, code, caller)
    account = self.env.State().GetStateObject(*self.address)
    return
}

func (self *Execution) exec(contextAddr *common.Address, code []byte, caller vm.ContextRef) (ret []byte, err error) {
    start := time.Now()

    env := self.env
    evm := self.evm
    if env.Depth() > int(params.CallCreateDepth.Int64()) {
        caller.ReturnGas(self.Gas, self.price)

        return nil, vm.DepthError{}
    }

    vsnapshot := env.State().Copy()
    var createAccount bool
    if self.address == nil {
        // Generate a new address
        nonce := env.State().GetNonce(caller.Address())
        env.State().SetNonce(caller.Address(), nonce+1)

        addr := crypto.CreateAddress(caller.Address(), nonce)

        self.address = &addr
        createAccount = true
    }
    snapshot := env.State().Copy()

    var (
        from = env.State().GetStateObject(caller.Address())
        to   *state.StateObject
    )
    if createAccount {
        to = env.State().CreateAccount(*self.address)
    } else {
        to = env.State().GetOrNewStateObject(*self.address)
    }

    err = env.Transfer(from, to, self.value)
    if err != nil {
        env.State().Set(vsnapshot)

        caller.ReturnGas(self.Gas, self.price)

        return nil, ValueTransferErr("insufficient funds to transfer value. Req %v, has %v", self.value, from.Balance())
    }

    context := vm.NewContext(caller, to, self.value, self.Gas, self.price)
    context.SetCallCode(contextAddr, code)

    ret, err = evm.Run(context, self.input)
    evm.Printf("message call took %v", time.Since(start)).Endl()
    if err != nil {
        env.State().Set(snapshot)
    }

    return
}