frostfs-sdk-go/pkg/policy/query.go

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package policy
import (
"errors"
"fmt"
"strings"
"github.com/nspcc-dev/neofs-api-go/pkg/netmap"
)
var (
// ErrInvalidNumber is returned when a value of SELECT is 0.
ErrInvalidNumber = errors.New("policy: expected positive integer")
// ErrUnknownClause is returned when a statement(clause) in a query is unknown.
ErrUnknownClause = errors.New("policy: unknown clause")
// ErrUnknownOp is returned when an operation in a query is unknown.
ErrUnknownOp = errors.New("policy: unknown operation")
// ErrUnknownFilter is returned when a value of FROM in a query is unknown.
ErrUnknownFilter = errors.New("policy: filter not found")
// ErrUnknownSelector is returned when a value of IN is unknown.
ErrUnknownSelector = errors.New("policy: selector not found")
)
func parse(s string) (*query, error) {
q := new(query)
err := parser.Parse(strings.NewReader(s), q)
if err != nil {
return nil, err
}
return q, nil
}
// Parse parses s into a placement policy.
func Parse(s string) (*netmap.PlacementPolicy, error) {
q, err := parse(s)
if err != nil {
return nil, err
}
seenFilters := map[string]bool{}
fs := make([]*netmap.Filter, 0, len(q.Filters))
for _, qf := range q.Filters {
f, err := filterFromOrChain(qf.Value, seenFilters)
if err != nil {
return nil, err
}
f.SetName(qf.Name)
fs = append(fs, f)
seenFilters[qf.Name] = true
}
seenSelectors := map[string]bool{}
ss := make([]*netmap.Selector, 0, len(q.Selectors))
for _, qs := range q.Selectors {
if qs.Filter != netmap.MainFilterName && !seenFilters[qs.Filter] {
return nil, fmt.Errorf("%w: '%s'", ErrUnknownFilter, qs.Filter)
}
s := netmap.NewSelector()
switch len(qs.Bucket) {
case 1: // only bucket
s.SetAttribute(qs.Bucket[0])
case 2: // clause + bucket
s.SetClause(clauseFromString(qs.Bucket[0]))
s.SetAttribute(qs.Bucket[1])
}
s.SetName(qs.Name)
seenSelectors[qs.Name] = true
s.SetFilter(qs.Filter)
if qs.Count == 0 {
return nil, fmt.Errorf("%w: SELECT", ErrInvalidNumber)
}
s.SetCount(qs.Count)
ss = append(ss, s)
}
rs := make([]*netmap.Replica, 0, len(q.Replicas))
for _, qr := range q.Replicas {
r := netmap.NewReplica()
if qr.Selector != "" {
if !seenSelectors[qr.Selector] {
return nil, fmt.Errorf("%w: '%s'", ErrUnknownSelector, qr.Selector)
}
r.SetSelector(qr.Selector)
}
if qr.Count == 0 {
return nil, fmt.Errorf("%w: REP", ErrInvalidNumber)
}
r.SetCount(uint32(qr.Count))
rs = append(rs, r)
}
p := new(netmap.PlacementPolicy)
p.SetFilters(fs...)
p.SetSelectors(ss...)
p.SetReplicas(rs...)
p.SetContainerBackupFactor(q.CBF)
return p, nil
}
func clauseFromString(s string) netmap.Clause {
switch strings.ToUpper(s) {
case "SAME":
return netmap.ClauseSame
case "DISTINCT":
return netmap.ClauseDistinct
default:
return 0
}
}
func filterFromOrChain(expr *orChain, seen map[string]bool) (*netmap.Filter, error) {
var fs []*netmap.Filter
for _, ac := range expr.Clauses {
f, err := filterFromAndChain(ac, seen)
if err != nil {
return nil, err
}
fs = append(fs, f)
}
if len(fs) == 1 {
return fs[0], nil
}
f := netmap.NewFilter()
f.SetOperation(netmap.OpOR)
f.SetInnerFilters(fs...)
return f, nil
}
func filterFromAndChain(expr *andChain, seen map[string]bool) (*netmap.Filter, error) {
var fs []*netmap.Filter
for _, fe := range expr.Clauses {
var f *netmap.Filter
var err error
if fe.Expr != nil {
f, err = filterFromSimpleExpr(fe.Expr, seen)
} else {
f = netmap.NewFilter()
f.SetName(fe.Reference)
}
if err != nil {
return nil, err
}
fs = append(fs, f)
}
if len(fs) == 1 {
return fs[0], nil
}
f := netmap.NewFilter()
f.SetOperation(netmap.OpAND)
f.SetInnerFilters(fs...)
return f, nil
}
func filterFromSimpleExpr(se *simpleExpr, seen map[string]bool) (*netmap.Filter, error) {
f := netmap.NewFilter()
f.SetKey(se.Key)
switch se.Op {
case "EQ":
f.SetOperation(netmap.OpEQ)
case "NE":
f.SetOperation(netmap.OpNE)
case "GE":
f.SetOperation(netmap.OpGE)
case "GT":
f.SetOperation(netmap.OpGT)
case "LE":
f.SetOperation(netmap.OpLE)
case "LT":
f.SetOperation(netmap.OpLT)
default:
return nil, fmt.Errorf("%w: '%s'", ErrUnknownOp, se.Op)
}
f.SetValue(se.Value)
return f, nil
}