1 files changed, 110 insertions, 0 deletions
diff --git a/common/natspec/statereg.go b/common/natspec/statereg.go
new file mode 100644
index 000000000..cb5dd4ce1
--- /dev/null
+++ b/common/natspec/statereg.go
@@ -0,0 +1,110 @@
+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
+
+}