package natspec
import (
"encoding/binary"
"fmt"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/xeth"
"io/ioutil"
"net/http"
)
type StateReg struct {
xeth *xeth.XEth
caURL, caNatSpec string //contract addresses
}
func NewStateReg(_xeth *xeth.XEth) (self *StateReg) {
self.xeth = _xeth
self.testCreateContracts()
return
}
const codeURLhint = "0x33600081905550609c8060136000396000f30060003560e060020a900480632f926732" +
"14601f578063f39ec1f714603157005b602b6004356024356044565b60006000f35b603a" +
"600435607f565b8060005260206000f35b600054600160a060020a031633600160a06002" +
"0a031614606257607b565b8060016000848152602001908152602001600020819055505b" +
"5050565b60006001600083815260200190815260200160002054905091905056"
const codeNatSpec = "0x33600081905550609c8060136000396000f30060003560e060020a900480632f926732" +
"14601f578063f39ec1f714603157005b602b6004356024356044565b60006000f35b603a" +
"600435607f565b8060005260206000f35b600054600160a060020a031633600160a06002" +
"0a031614606257607b565b8060016000848152602001908152602001600020819055505b" +
"5050565b60006001600083815260200190815260200160002054905091905056"
func (self *StateReg) testCreateContracts() {
var err error
self.caURL, err = self.xeth.Transact(self.xeth.Coinbase(), "", "100000", "", self.xeth.DefaultGas().String(), codeURLhint)
if err != nil {
panic(err)
}
self.caNatSpec, err = self.xeth.Transact(self.xeth.Coinbase(), "", "100000", "", self.xeth.DefaultGas().String(), codeNatSpec)
if err != nil {
panic(err)
}
}
func (self *StateReg) GetURLhint(hash string) (url string, err error) {
url_hex := self.xeth.StorageAt(self.caURL, storageAddress(0, common.Hex2Bytes(hash)))
url = string(common.Hex2Bytes(url_hex))
l := len(url)
for (l > 0) && (url[l-1] == 0) {
l--
}
url = url[:l]
if l == 0 {
err = fmt.Errorf("GetURLhint: URL hint not found")
}
return
}
func storageAddress(varidx uint32, key []byte) string {
data := make([]byte, 64)
binary.BigEndian.PutUint32(data[28:32], varidx)
copy(data[32:64], key[0:32])
return common.Bytes2Hex(crypto.Sha3(data))
}
func (self *StateReg) GetNatSpec(codehash string) (hash string, err error) {
hash = self.xeth.StorageAt(self.caNatSpec, storageAddress(0, common.Hex2Bytes(codehash)))
return
}
func (self *StateReg) GetContent(hash string) (content []byte, err error) {
// get URL
url, err := self.GetURLhint(hash)
if err != nil {
return
}
// retrieve content
resp, err := http.Get(url)
defer resp.Body.Close()
if err != nil {
return
}
content, err = ioutil.ReadAll(resp.Body)
if err != nil {
return
}
// check hash
if common.Bytes2Hex(crypto.Sha3(content)) != hash {
content = nil
err = fmt.Errorf("GetContent error: content hash mismatch")
}
return
}
