// HashToHash(key) resolves contenthash for key (a hash) using HashReg
// resolution is costless non-transactional
// implemented as direct retrieval from db
func (self *Registrar) HashToHash(khash common.Hash) (chash common.Hash, err error) {
if zero.MatchString(HashRegAddr) {
return common.Hash{}, fmt.Errorf("HashReg address is not set")
}
// look up in hashReg
at := HashRegAddr[2:]
key := storageAddress(storageMapping(storageIdx2Addr(1), khash[:]))
hash := self.backend.StorageAt(at, key)
if hash == "0x0" || len(hash) < 3 || (hash == common.Hash{}.Hex()) {
err = fmt.Errorf("HashToHash: content hash not found for '%v'", khash.Hex())
return
}
copy(chash[:], common.Hex2BytesFixed(hash[2:], 32))
return
}
// SetUrlToHash(from, hash, url) registers a url to a content hash so that the content can be fetched
// address is used as sender for the transaction and will be the owner of a new
// registry entry on first time use
// FIXME: silently doing nothing if sender is not the owner
// note that with content addressed storage, this step is no longer necessary
func (self *Registrar) SetUrlToHash(address common.Address, hash common.Hash, url string) (txh string, err error) {
if zero.MatchString(UrlHintAddr) {
return "", fmt.Errorf("UrlHint address is not set")
}
hashHex := common.Bytes2Hex(hash[:])
var urlHex string
urlb := []byte(url)
var cnt byte
n := len(urlb)
for n > 0 {
if n > 32 {
n = 32
}
urlHex = common.Bytes2Hex(urlb[:n])
urlb = urlb[n:]
n = len(urlb)
bcnt := make([]byte, 32)
bcnt[31] = cnt
data := registerUrlAbi +
hashHex +
common.Bytes2Hex(bcnt) +
common.Bytes2Hex(common.Hex2BytesFixed(urlHex, 32))
txh, err = self.backend.Transact(
address.Hex(),
UrlHintAddr,
"", "", "", "",
data,
)
if err != nil {
return
}
cnt++
}
return
}