snapshot of https://github.com/casbin/casbin.git (master, 2026-09-15; blobs > 131072B omitted)

persist/adapter.go

@@ -0,0 +1,116 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package persist
+
+import (
+	"bytes"
+	"encoding/csv"
+	"errors"
+	"strings"
+
+	"github.com/casbin/casbin/v3/model"
+)
+
+// LoadPolicyLine loads a text line as a policy rule to model.
+func LoadPolicyLine(line string, m model.Model) error {
+	if line == "" || strings.HasPrefix(line, "#") {
+		return nil
+	}
+
+	r := csv.NewReader(strings.NewReader(line))
+	r.Comma = ','
+	r.Comment = '#'
+	r.TrimLeadingSpace = true
+
+	tokens, err := r.Read()
+	if err != nil {
+		return err
+	}
+
+	return LoadPolicyArray(tokens, m)
+}
+
+// PolicyLineToCsv serializes a policy type and its rule fields into a CSV-safe line.
+// Fields are separated by ", " to match the conventional layout of Casbin policy
+// files, which LoadPolicyLine accepts because its reader trims leading spaces.
+// Fields containing commas are properly quoted so the line can be round-tripped
+// through LoadPolicyLine without corruption.
+func PolicyLineToCsv(ptype string, rule []string) (string, error) {
+	record := append([]string{ptype}, rule...)
+
+	// Each field is written as its own single-field record so that the standard
+	// library decides on quoting, then the fields are joined with ", ".
+	var buf bytes.Buffer
+	w := csv.NewWriter(&buf)
+	fields := make([]string, 0, len(record))
+	for _, field := range record {
+		buf.Reset()
+		if err := w.Write([]string{field}); err != nil {
+			return "", err
+		}
+		w.Flush()
+		if err := w.Error(); err != nil {
+			return "", err
+		}
+		fields = append(fields, strings.TrimRight(buf.String(), "\r\n"))
+	}
+
+	return strings.Join(fields, ", "), nil
+}
+
+// LoadPolicyArray loads a policy rule to model.
+func LoadPolicyArray(rule []string, m model.Model) error {
+	if len(rule) == 0 || rule[0] == "" {
+		return errors.New("invalid policy rule: missing policy type")
+	}
+
+	key := rule[0]
+	sec := key[:1]
+	ok, err := m.HasPolicyEx(sec, key, rule[1:])
+	if err != nil {
+		return err
+	}
+	if ok {
+		return nil // skip duplicated policy
+	}
+
+	err = m.AddPolicy(sec, key, rule[1:])
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Adapter is the interface for Casbin adapters.
+type Adapter interface {
+	// LoadPolicy loads all policy rules from the storage.
+	LoadPolicy(model model.Model) error
+	// SavePolicy saves all policy rules to the storage.
+	SavePolicy(model model.Model) error
+
+	// AddPolicy adds a policy rule to the storage.
+	// This is part of the Auto-Save feature.
+	AddPolicy(sec string, ptype string, rule []string) error
+	// RemovePolicy removes a policy rule from the storage.
+	// This is part of the Auto-Save feature.
+	RemovePolicy(sec string, ptype string, rule []string) error
+	// RemoveFilteredPolicy removes policy rules that match the filter from the storage.
+	// This is part of the Auto-Save feature.
+	RemoveFilteredPolicy(sec string, ptype string, fieldIndex int, fieldValues ...string) error
+}