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 {
+
+class OncValueSignature;
+
+// Iterate over both a hierarchical onc signature and an onc value. By comparing
+// the address of a signature object to the list of signatures in
+// "onc_signature.h", accurate signature-specific functions can be applied.  It
+// is expected that the hierarchy of the signature is complete.
+class Mapper {
+ public:
+  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|, which drops unknown fields by default. Sets
+  // |found_unknown_fieldname| to true if this dictionary contains any unknown
+  // fields. Returns false if nested errors occured.
+  virtual bool MapFields(
+      const OncValueSignature& object_signature,
+      const base::DictionaryValue& onc_object,
+      bool* found_unknown_fieldname,
+      base::DictionaryValue* result);

[stevenjb, 2012/10/11 19:54:00]

Returning a bool here is inconsistent and confusing; could we return a scoped
Dictionary instead and either return an empty dictionary on error, pass multiple
bool*, or use a result code?

[pneubeck (no reviews), 2012/10/15 13:57:44]

I opted for a second bool argument. This keeps the flexibility of the passed
Dictionary* (there may be already some previously created fields) and makes the
meaning clearer.

+
+  // Maps the value |onc_value| of field |field_name| according to its field
+  // signature in |object_signature| using |MapValue|. Sets
+  // |found_unknown_fieldname| 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_fieldname);
+
+  // 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 (doesn't happen in the default
+  // implementation).
+  virtual scoped_ptr<base::ListValue> MapArray(
+      const OncValueSignature& array_signature,
+      const base::ListValue& onc_array,
+      bool* nested_error_occured);
+
+  DISALLOW_COPY_AND_ASSIGN(Mapper);
+};
+
+}  // namespace onc
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_NETWORK_SETTINGS_ONC_MAPPER_H_