Implementation of ONC signature, validator and normalizer.

chrome/browser/chromeos/network_settings/onc_mapper.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_NETWORK_SETTINGS_ONC_MAPPER_H_
+#define CHROME_BROWSER_CHROMEOS_NETWORK_SETTINGS_ONC_MAPPER_H_
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+class Value;
+class DictionaryValue;
+class ListValue;
+}
+
+namespace chromeos {
+namespace onc {
+
+struct OncValueSignature;
+
+// This class implements a DeepCopy of base::Values for ONC objects that
+// iterates over both the ONC signature and the object hierarchy. DCHECKs if a
+// field signature without value signature or an array signature without entry
+// signature is reached.
+//
+// The general term "map" is used here, as this class is meant as base class and
+// the copy behavior can be adapted by overriding the methods. By comparing the
+// address of a signature object to the list of signatures in "onc_signature.h",
+// accurate signature-specific translations or validations can be applied in the
+// overriding methods.
+//
+// The ONC validator and normalizer derive from this class and adapt the default
+// copy behavior.
+class Mapper {
+ public:
+  Mapper();
+  virtual ~Mapper();
+
+ protected:
+  // Calls |MapObject|, |MapArray| and |MapPrimitive| according to |onc_value|'s
+  // type. By default aborts on nested errors in arrays. Result of the mapping
+  // is returned. On error returns NULL.
+  virtual scoped_ptr<base::Value> MapValue(
+    const OncValueSignature& signature,
+    const base::Value& onc_value);
+
+  // Maps objects/dictionaries. By default calls |MapFields|, which recurses
+  // into each field of |onc_object|, and aborts on unknown fields. Result of
+  // the mapping is returned. On error returns NULL.
+  virtual scoped_ptr<base::DictionaryValue> MapObject(
+      const OncValueSignature& signature,
+      const base::DictionaryValue& onc_object);
+
+  // Maps primitive values like BinaryValue, StringValue, IntegerValue... (all
+  // but dictionaries and lists). By default copies |onc_primitive|. Result of
+  // the mapping is returned. On error returns NULL.
+  virtual scoped_ptr<base::Value> MapPrimitive(
+    const OncValueSignature& signature,
+    const base::Value& onc_primitive);
+
+  // Maps each field of the given |onc_object| according to
+  // |object_signature|. Adds the mapping of each field to |result| using
+  // |MapField| and drops unknown fields by default. Sets
+  // |found_unknown_field| to true if this dictionary contains any unknown
+  // fields. Set |nested_error_occured| to true if nested errors occured.
+  virtual void MapFields(
+      const OncValueSignature& object_signature,
+      const base::DictionaryValue& onc_object,
+      bool* found_unknown_field,
+      bool* nested_error_occured,
+      base::DictionaryValue* result);
+
+  // Maps the value |onc_value| of field |field_name| according to its field
+  // signature in |object_signature| using |MapValue|. Sets
+  // |found_unknown_field| to true if |field_name| cannot be found in
+  // |object_signature|, which by default is an error. Result of the mapping is
+  // returned. On error returns NULL.
+  virtual scoped_ptr<base::Value> MapField(
+      const std::string& field_name,
+      const OncValueSignature& object_signature,
+      const base::Value& onc_value,
+      bool* found_unknown_field);
+
+  // Maps the array |onc_array| according to |array_signature|, which defines
+  // the type of the entries. Maps each entry by calling |MapValue|. If any of
+  // the nested mappings failed, the flag |nested_error_occured| is set to true
+  // and the entry is dropped from the result. The resulting array is
+  // returned. On error returns NULL.
+  virtual scoped_ptr<base::ListValue> MapArray(
+      const OncValueSignature& array_signature,
+      const base::ListValue& onc_array,
+      bool* nested_error_occured);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Mapper);
+};
+
+}  // namespace onc
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_NETWORK_SETTINGS_ONC_MAPPER_H_