package governance import ( "sort" "github.com/nspcc-dev/neo-go/pkg/crypto/keys" "github.com/pkg/errors" ) var ( errNotEnoughKeys = errors.New("alphabet list in mainnet is too short") errNotEqualLen = errors.New("old and new alphabet lists have different length") errEmptySidechain = errors.New("sidechain list is empty") ) // newAlphabetList returns updated list of sidechain keys with no more than 1\3 // of new keys from mainnet list. Function returns `errEmptySidechain` if // sidechain list is empty. Function returns `errNotEnoughKeys` if mainnet // list contains less keys than sidechain list. Function returns (nil, nil) if // mainnet list contains all keys from sidechain list. func newAlphabetList(sidechain, mainnet keys.PublicKeys) (keys.PublicKeys, error) { ln := len(sidechain) if ln == 0 { return nil, errEmptySidechain } if len(mainnet) < ln { return nil, errors.Wrapf(errNotEnoughKeys, "expecting %d keys", ln) } hmap := make(map[string]bool, ln) result := make(keys.PublicKeys, 0, ln) for _, node := range sidechain { hmap[node.Address()] = false } newNodes := 0 newNodeLimit := (ln - 1) / 3 for i := 0; i < ln; i++ { if newNodes == newNodeLimit { break } mainnetAddr := mainnet[i].Address() if _, ok := hmap[mainnetAddr]; !ok { newNodes++ } else { hmap[mainnetAddr] = true } result = append(result, mainnet[i]) } if newNodes == 0 { return nil, nil } for _, node := range sidechain { if len(result) == ln { break } if !hmap[node.Address()] { result = append(result, node) } } sort.Sort(result) return result, nil } // updateInnerRing function removes `before` keys from `innerRing` and adds // `after` keys in the list. If length of `before` and `after` is not the same // then function returns errNotEqualLen func updateInnerRing(innerRing, before, after keys.PublicKeys) (keys.PublicKeys, error) { lnBefore := len(before) if lnBefore != len(after) { return nil, errNotEqualLen } result := make(keys.PublicKeys, 0, len(innerRing)) // O(n^2) for 7 nodes is not THAT bad. loop: for i := range innerRing { for j := range before { if innerRing[i].Equal(before[j]) { result = append(result, after[j]) continue loop } } result = append(result, innerRing[i]) } return result, nil }