// HashToUrl(contenthash) resolves the url for contenthash using UrlHint
// resolution is costless non-transactional
// implemented as direct retrieval from db
// if we use content addressed storage, this step is no longer necessary
func (self *Registrar) HashToUrl(chash common.Hash) (uri string, err error) {
if zero.MatchString(UrlHintAddr) {
return "", fmt.Errorf("UrlHint address is not set")
}
// look up in URL reg
var str string = " "
var idx uint32
for len(str) > 0 {
mapaddr := storageMapping(storageIdx2Addr(1), chash[:])
key := storageAddress(storageFixedArray(mapaddr, storageIdx2Addr(idx)))
hex := self.backend.StorageAt(UrlHintAddr[2:], key)
str = string(common.Hex2Bytes(hex[2:]))
l := 0
for (l < len(str)) && (str[l] == 0) {
l++
}
str = str[l:]
uri = uri + str
idx++
}
if len(uri) == 0 {
err = fmt.Errorf("HashToUrl: URL hint not found for '%v'", chash.Hex())
}
return
}
// resolution is costless non-transactional
// implemented as direct retrieval from db
func (self *Resolver) KeyToContentHash(khash common.Hash) (chash common.Hash, err error) {
// look up in hashReg
at := common.Bytes2Hex(common.FromHex(HashRegContractAddress))
key := storageAddress(storageMapping(storageIdx2Addr(1), khash[:]))
hash := self.backend.StorageAt(at, key)
if hash == "0x0" || len(hash) < 3 {
err = fmt.Errorf("content hash not found for '%v'", khash.Hex())
return
}
copy(chash[:], common.Hex2BytesFixed(hash[2:], 32))
return
}
// 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) {
// 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("content hash not found for '%v'", khash.Hex())
return
}
copy(chash[:], common.Hex2BytesFixed(hash[2:], 32))
return
}
// retrieves the url-hint for the content hash -
// if we use content addressed storage, this step is no longer necessary
func (self *Resolver) ContentHashToUrl(chash common.Hash) (uri string, err error) {
// look up in URL reg
var str string = " "
var idx uint32
for len(str) > 0 {
mapaddr := storageMapping(storageIdx2Addr(1), chash[:])
key := storageAddress(storageFixedArray(mapaddr, storageIdx2Addr(idx)))
hex := self.backend.StorageAt(UrlHintContractAddress, key)
str = string(common.Hex2Bytes(hex[2:]))
l := len(str)
for (l > 0) && (str[l-1] == 0) {
l--
}
str = str[:l]
uri = uri + str
idx++
}
if len(uri) == 0 {
err = fmt.Errorf("GetURLhint: URL hint not found for '%v'", chash.Hex())
}
return
}