snapshot of https://github.com/ory/keto.git (master, 2026-09-16; blobs > 131072B omitted)

internal/x/graph/graph_utils.go

@@ -0,0 +1,53 @@
+// Copyright © 2023 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package graph
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"github.com/ory/keto/internal/relationtuple"
+)
+
+type contextKey string
+
+const visitedMapKey = contextKey("visitedMap")
+
+type stringSet struct {
+	m map[string]struct{}
+	l sync.Mutex
+}
+
+func newStringSet() *stringSet {
+	return &stringSet{m: make(map[string]struct{})}
+}
+
+func (s *stringSet) addNoDuplicate(el fmt.Stringer) bool {
+	s.l.Lock()
+	defer s.l.Unlock()
+
+	if _, found := s.m[el.String()]; found {
+		return true
+	}
+	s.m[el.String()] = struct{}{}
+	return false
+}
+
+func InitVisited(ctx context.Context) context.Context {
+	if _, ok := ctx.Value(visitedMapKey).(*stringSet); !ok {
+		ctx = context.WithValue(ctx, visitedMapKey, newStringSet())
+	}
+	return ctx
+}
+
+func CheckAndAddVisited(ctx context.Context, current relationtuple.Subject) (context.Context, bool) {
+	set, ok := ctx.Value(visitedMapKey).(*stringSet)
+	if !ok {
+		set = newStringSet()
+		ctx = context.WithValue(ctx, visitedMapKey, set)
+	}
+
+	return ctx, set.addNoDuplicate(current.UniqueID())
+}