frostfs-node/pkg/innerring/processors/governance/list.go

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package governance
import (
"errors"
"fmt"
"sort"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
)
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 an updated list of sidechain keys with no more than 1\3
// of new keys from the mainnet list. The function returns `errEmptySidechain` if
// the sidechain list is empty. The function returns `errNotEnoughKeys` if the mainnet
// list contains less keys than the sidechain list. The function returns (nil, nil) if
// the mainnet list contains all keys from the sidechain list.
//
// Sorts passed slices.
func newAlphabetList(sidechain, mainnet keys.PublicKeys) (keys.PublicKeys, error) {
sort.Sort(sidechain)
sort.Sort(mainnet)
ln := len(sidechain)
if ln == 0 {
return nil, errEmptySidechain
}
if len(mainnet) < ln {
return nil, fmt.Errorf("%w: expecting %d keys", errNotEnoughKeys, 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 _, node := range mainnet {
if len(result) == ln {
break
}
limitReached := newNodes == newNodeLimit
mainnetAddr := node.Address()
if _, ok := hmap[mainnetAddr]; !ok {
if limitReached {
continue
}
newNodes++
} else {
hmap[mainnetAddr] = true
}
result = append(result, node)
}
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 the length of `before` and `after` is not the same,
// the 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
}