frostfs-node/pkg/util/attributes/parser.go

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package attributes
import (
"errors"
"fmt"
"strings"
"github.com/nspcc-dev/neofs-api-go/pkg/netmap"
)
const (
pairSeparator = "/"
keyValueSeparator = ":"
)
var (
errEmptyChain = errors.New("empty attribute chain")
errNonUniqueBucket = errors.New("attributes must contain unique keys")
errUnexpectedKey = errors.New("attributes contain unexpected key")
)
// ParseV2Attributes parses strings like "K1:V1/K2:V2/K3:V3" into netmap
// attributes. Supports escaped symbols "\:", "\/" and "\\".
func ParseV2Attributes(attrs []string, excl []string) ([]*netmap.NodeAttribute, error) {
restricted := make(map[string]struct{}, len(excl))
for i := range excl {
restricted[excl[i]] = struct{}{}
}
cache := make(map[string]*netmap.NodeAttribute, len(attrs))
for i := range attrs {
line := strings.Trim(attrs[i], pairSeparator)
line = replaceEscaping(line, false) // replaced escaped symbols with non-printable symbols
chain := strings.Split(line, pairSeparator)
if len(chain) == 0 {
return nil, errEmptyChain
}
var parentKey string // backtrack parents in next pairs
for j := range chain {
pair := strings.Split(chain[j], keyValueSeparator)
if len(pair) != 2 {
return nil, fmt.Errorf("incorrect attribute pair %s", chain[j])
}
key := pair[0]
value := pair[1]
if at, ok := cache[key]; ok && at.Value() != value {
return nil, errNonUniqueBucket
}
if _, ok := restricted[key]; ok {
return nil, errUnexpectedKey
}
// replace non-printable symbols with escaped symbols without escape character
key = replaceEscaping(key, true)
value = replaceEscaping(value, true)
attribute := netmap.NewNodeAttribute()
attribute.SetKey(key)
attribute.SetValue(value)
if parentKey != "" {
attribute.SetParentKeys(parentKey)
}
parentKey = key
cache[key] = attribute
}
}
result := make([]*netmap.NodeAttribute, 0, len(cache))
for _, v := range cache {
result = append(result, v)
}
return result, nil
}
func replaceEscaping(target string, rollback bool) (s string) {
const escChar = `\`
var (
oldPairSep = escChar + pairSeparator
oldKVSep = escChar + keyValueSeparator
oldEsc = escChar + escChar
newPairSep = string(uint8(1))
newKVSep = string(uint8(2))
newEsc = string(uint8(3))
)
if rollback {
oldPairSep, oldKVSep, oldEsc = newPairSep, newKVSep, newEsc
newPairSep = pairSeparator
newKVSep = keyValueSeparator
newEsc = escChar
}
s = strings.ReplaceAll(target, oldEsc, newEsc)
s = strings.ReplaceAll(s, oldPairSep, newPairSep)
s = strings.ReplaceAll(s, oldKVSep, newKVSep)
return
}