// scanAddressRange scans backwards from end to start many addresses in the
// account branch, and return the first index that is found on the blockchain.
// If the address doesn't exist, false is returned as the first argument.
func (w *Wallet) scanAddressRange(account uint32, branch uint32, start int,
end int, chainClient *chain.RPCClient) (bool, int, error) {
var addresses []dcrutil.Address
err := walletdb.View(w.db, func(tx walletdb.ReadTx) error {
addrmgrNs := tx.ReadBucket(waddrmgrNamespaceKey)
var err error
addresses, err = w.Manager.AddressesDerivedFromDbAcct(addrmgrNs,
uint32(start), uint32(end+1), account, branch)
if err != nil {
return errDerivation
}
return nil
})
if err != nil {
return false, 0, err
}
// Whether or not the addresses exist is encoded as a binary
// bitset.
exists, err := chainClient.ExistsAddresses(addresses)
if err != nil {
return false, 0, err
}
existsB, err := hex.DecodeString(exists)
if err != nil {
return false, 0, err
}
set := bitset.Bytes(existsB)
// Prevent a panic when an empty message is passed as a response.
if len(set) == 0 {
return false, 0, nil
}
// Scan backwards and return if we find an address exists.
idx := end
itr := len(addresses) - 1
for idx >= start {
// If the address exists in the mempool or blockchain according
// to the bit set returned, return this index.
if set.Get(itr) {
return true, idx, nil
}
itr--
idx--
}
return false, 0, nil
}
