frostfs-sdk-go/policy/encode.go

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package policy
import (
"fmt"
"strconv"
"strings"
"github.com/nspcc-dev/neofs-sdk-go/netmap"
)
// Encode parses data of PlacementPolicy to a string.
func Encode(p *netmap.PlacementPolicy) []string {
if p == nil {
return nil
}
var (
replicas = p.Replicas()
selectors = p.Selectors()
filters = p.Filters()
)
// 1 for container backup factor
result := make([]string, 0, len(replicas)+len(selectors)+len(filters)+1)
// first print replicas
encodeReplicas(replicas, &result)
// then backup factor
if backupFactor := p.ContainerBackupFactor(); backupFactor != 0 {
result = append(result, fmt.Sprintf("CBF %d", backupFactor))
}
// then selectors
encodeSelectors(selectors, &result)
// then filters
encodeFilters(filters, &result)
return result
}
func encodeReplicas(replicas []netmap.Replica, dst *[]string) {
builder := new(strings.Builder)
for _, replica := range replicas {
builder.WriteString("REP ")
builder.WriteString(strconv.FormatUint(uint64(replica.Count()), 10))
if s := replica.Selector(); s != "" {
builder.WriteString(" IN ")
builder.WriteString(s)
}
*dst = append(*dst, builder.String())
builder.Reset()
}
}
func encodeSelectors(selectors []netmap.Selector, dst *[]string) {
builder := new(strings.Builder)
for _, selector := range selectors {
builder.WriteString("SELECT ")
builder.WriteString(strconv.FormatUint(uint64(selector.Count()), 10))
if a := selector.Attribute(); a != "" {
builder.WriteString(" IN")
switch selector.Clause() {
case netmap.ClauseSame:
builder.WriteString(" SAME ")
case netmap.ClauseDistinct:
builder.WriteString(" DISTINCT ")
default:
builder.WriteString(" ")
}
builder.WriteString(a)
}
if f := selector.Filter(); f != "" {
builder.WriteString(" FROM ")
builder.WriteString(f)
}
if n := selector.Name(); n != "" {
builder.WriteString(" AS ")
builder.WriteString(n)
}
*dst = append(*dst, builder.String())
builder.Reset()
}
}
func encodeFilters(filters []netmap.Filter, dst *[]string) {
builder := new(strings.Builder)
for _, filter := range filters {
builder.WriteString("FILTER ")
builder.WriteString(encodeFilter(&filter))
*dst = append(*dst, builder.String())
builder.Reset()
}
}
func encodeFilter(filter *netmap.Filter) string {
builder := new(strings.Builder)
unspecified := filter.Operation() == 0
if k := filter.Key(); k != "" {
builder.WriteString(k)
builder.WriteString(" ")
builder.WriteString(filter.Operation().String())
builder.WriteString(" ")
builder.WriteString(filter.Value())
} else if n := filter.Name(); unspecified && n != "" {
builder.WriteString("@")
builder.WriteString(n)
}
for i, subfilter := range filter.InnerFilters() {
if i != 0 {
builder.WriteString(" ")
builder.WriteString(filter.Operation().String())
builder.WriteString(" ")
}
builder.WriteString(encodeFilter(&subfilter))
}
if n := filter.Name(); n != "" && !unspecified {
builder.WriteString(" AS ")
builder.WriteString(n)
}
return builder.String()
}