path: root/ethchain/transaction.go

package ethchain

import (
    "bytes"
    "fmt"
    "github.com/ethereum/eth-go/ethutil"
    "github.com/obscuren/secp256k1-go"
    "math/big"
)

var ContractAddr = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}

type Transaction struct {
    Nonce     uint64
    Recipient []byte
    Value     *big.Int
    Gas       *big.Int
    Gasprice  *big.Int
    Data      []string
    v         byte
    r, s      []byte

    // Indicates whether this tx is a contract creation transaction
    contractCreation bool
}

func NewContractCreationTx(value, gasprice *big.Int, data []string) *Transaction {
    return &Transaction{Value: value, Gasprice: gasprice, Data: data, contractCreation: true}
}

func NewTransactionMessage(to []byte, value, gasprice, gas *big.Int, data []string) *Transaction {
    return &Transaction{Recipient: to, Value: value, Gasprice: gasprice, Gas: gas, Data: data}
}

func NewTransactionFromBytes(data []byte) *Transaction {
    tx := &Transaction{}
    tx.RlpDecode(data)

    return tx
}

func NewTransactionFromValue(val *ethutil.Value) *Transaction {
    tx := &Transaction{}
    tx.RlpValueDecode(val)

    return tx
}

func (tx *Transaction) Hash() []byte {
    data := make([]interface{}, len(tx.Data))
    for i, val := range tx.Data {
        data[i] = val
    }

    preEnc := []interface{}{
        tx.Nonce,
        tx.Recipient,
        tx.Value,
        data,
    }

    return ethutil.Sha3Bin(ethutil.Encode(preEnc))
}

func (tx *Transaction) IsContract() bool {
    return bytes.Compare(tx.Recipient, ContractAddr) == 0
}

func (tx *Transaction) Signature(key []byte) []byte {
    hash := tx.Hash()

    sig, _ := secp256k1.Sign(hash, key)

    return sig
}

func (tx *Transaction) PublicKey() []byte {
    hash := tx.Hash()

    // If we don't make a copy we will overwrite the existing underlying array
    dst := make([]byte, len(tx.r))
    copy(dst, tx.r)

    sig := append(dst, tx.s...)
    sig = append(sig, tx.v-27)

    pubkey, _ := secp256k1.RecoverPubkey(hash, sig)

    return pubkey
}

func (tx *Transaction) Sender() []byte {
    pubkey := tx.PublicKey()

    // Validate the returned key.
    // Return nil if public key isn't in full format
    if pubkey[0] != 4 {
        return nil
    }

    return ethutil.Sha3Bin(pubkey[1:])[12:]
}

func (tx *Transaction) Sign(privk []byte) error {

    sig := tx.Signature(privk)

    tx.r = sig[:32]
    tx.s = sig[32:64]
    tx.v = sig[64] + 27

    return nil
}

func (tx *Transaction) RlpData() interface{} {
    data := []interface{}{tx.Nonce, tx.Value, tx.Gasprice}

    if !tx.contractCreation {
        data = append(data, tx.Recipient, tx.Gas)
    }

    return append(data, ethutil.NewSliceValue(tx.Data).Slice(), tx.v, tx.r, tx.s)
}

func (tx *Transaction) RlpValue() *ethutil.Value {
    return ethutil.NewValue(tx.RlpData())
}

func (tx *Transaction) RlpEncode() []byte {
    return tx.RlpValue().Encode()
}

func (tx *Transaction) RlpDecode(data []byte) {
    tx.RlpValueDecode(ethutil.NewValueFromBytes(data))
}

//   [ NONCE, VALUE, GASPRICE, TO, GAS, DATA, V, R, S ]
//["" "\x03\xe8" "" "\xaa" "\x03\xe8" [] '\x1c' "\x10C\x15\xfc\xe5\xd0\t\xe4\r\xe7\xefa\xf5aE\xd6\x14\xaed\xb5.\xf5\x18\xa1S_j\xe0A\xdc5U" "dQ\nqy\xf8\x17+\xbf\xd7Jx\xda-\xcb\xd7\xcfQ\x1bI\xb8_9\b\x80\xea듎i|\x1f"]
func (tx *Transaction) RlpValueDecode(decoder *ethutil.Value) {
    fmt.Println(decoder)
    tx.Nonce = decoder.Get(0).Uint()
    tx.Value = decoder.Get(1).BigInt()
    tx.Gasprice = decoder.Get(2).BigInt()

    // If the 4th item is a list(slice) this tx
    // is a contract creation tx
    if decoder.Get(3).IsList() {
        d := decoder.Get(3)
        tx.Data = make([]string, d.Len())
        for i := 0; i < d.Len(); i++ {
            tx.Data[i] = d.Get(i).Str()
        }

        tx.v = byte(decoder.Get(4).Uint())
        tx.r = decoder.Get(5).Bytes()
        tx.s = decoder.Get(6).Bytes()

        tx.contractCreation = true
    } else {
        tx.Recipient = decoder.Get(3).Bytes()
        tx.Gas = decoder.Get(4).BigInt()

        d := decoder.Get(5)
        tx.Data = make([]string, d.Len())
        for i := 0; i < d.Len(); i++ {
            tx.Data[i] = d.Get(i).Str()
        }

        tx.v = byte(decoder.Get(6).Uint())
        tx.r = decoder.Get(7).Bytes()
        tx.s = decoder.Get(8).Bytes()
    }
    /*
        tx.Nonce = decoder.Get(0).Uint()
        tx.Recipient = decoder.Get(1).Bytes()
        tx.Value = decoder.Get(2).BigInt()

        d := decoder.Get(3)
        tx.Data = make([]string, d.Len())
        for i := 0; i < d.Len(); i++ {
            tx.Data[i] = d.Get(i).Str()
        }

        tx.v = byte(decoder.Get(4).Uint())
        tx.r = decoder.Get(5).Bytes()
        tx.s = decoder.Get(6).Bytes()
    */
}