onc_mapper.h revision 2a99a7e74a7f215066514fe81d2bfa6639d9eddd 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROMEOS_NETWORK_ONC_ONC_MAPPER_H_
6#define CHROMEOS_NETWORK_ONC_ONC_MAPPER_H_
7
8#include <string>
9
10#include "base/memory/scoped_ptr.h"
11#include "chromeos/chromeos_export.h"
12
13namespace base {
14class DictionaryValue;
15class ListValue;
16class Value;
17}
18
19namespace chromeos {
20namespace onc {
21
22struct OncValueSignature;
23
24// This class implements a DeepCopy of base::Values for ONC objects that
25// iterates over both the ONC signature and the object hierarchy. DCHECKs if a
26// field signature without value signature or an array signature without entry
27// signature is reached.
28//
29// The general term "map" is used here, as this class is meant as base class and
30// the copy behavior can be adapted by overriding the methods. By comparing the
31// address of a signature object to the list of signatures in "onc_signature.h",
32// accurate signature-specific translations or validations can be applied in the
33// overriding methods.
34//
35// The ONC validator and normalizer derive from this class and adapt the default
36// copy behavior.
37class Mapper {
38 public:
39  Mapper();
40  virtual ~Mapper();
41
42 protected:
43  // Calls |MapObject|, |MapArray| and |MapPrimitive| according to |onc_value|'s
44  // type, which always return an object of the according type. Result of the
45  // mapping is returned. Only on error sets |error| to true.
46  virtual scoped_ptr<base::Value> MapValue(const OncValueSignature& signature,
47                                           const base::Value& onc_value,
48                                           bool* error);
49
50  // Maps objects/dictionaries. By default calls |MapFields|, which recurses
51  // into each field of |onc_object|, and drops unknown fields. Result of the
52  // mapping is returned. Only on error sets |error| to true. In this
53  // implementation only unknown fields are errors.
54  virtual scoped_ptr<base::DictionaryValue> MapObject(
55      const OncValueSignature& signature,
56      const base::DictionaryValue& onc_object,
57      bool* error);
58
59  // Maps primitive values like BinaryValue, StringValue, IntegerValue... (all
60  // but dictionaries and lists). By default copies |onc_primitive|. Result of
61  // the mapping is returned. Only on error sets |error| to true.
62  virtual scoped_ptr<base::Value> MapPrimitive(
63      const OncValueSignature& signature,
64      const base::Value& onc_primitive,
65      bool* error);
66
67  // Maps each field of the given |onc_object| according to |object_signature|.
68  // Adds the mapping of each field to |result| using |MapField| and drops
69  // unknown fields by default. Sets |found_unknown_field| to true if this
70  // dictionary contains any unknown fields. Set |nested_error| to true only if
71  // nested errors occured.
72  virtual void MapFields(const OncValueSignature& object_signature,
73                         const base::DictionaryValue& onc_object,
74                         bool* found_unknown_field,
75                         bool* nested_error,
76                         base::DictionaryValue* result);
77
78  // Maps the value |onc_value| of field |field_name| according to its field
79  // signature in |object_signature| using |MapValue|. Sets
80  // |found_unknown_field| to true and returns NULL if |field_name| cannot be
81  // found in |object_signature|. Otherwise returns the mapping of |onc_value|.
82  virtual scoped_ptr<base::Value> MapField(
83      const std::string& field_name,
84      const OncValueSignature& object_signature,
85      const base::Value& onc_value,
86      bool* found_unknown_field,
87      bool* error);
88
89  // Maps the array |onc_array| according to |array_signature|, which defines
90  // the type of the entries. Maps each entry by calling |MapValue|. If any of
91  // the nested mappings failed, the flag |nested_error| is set to true and the
92  // entry is dropped from the result. Otherwise |nested_error| isn't
93  // modified. The resulting array is returned.
94  virtual scoped_ptr<base::ListValue> MapArray(
95      const OncValueSignature& array_signature,
96      const base::ListValue& onc_array,
97      bool* nested_error);
98
99  // Calls |MapValue| and returns its result. Called by |MapArray| for each
100  // entry and its index in the enclosing array.
101  virtual scoped_ptr<base::Value> MapEntry(int index,
102                                           const OncValueSignature& signature,
103                                           const base::Value& onc_value,
104                                           bool* error);
105
106 private:
107  DISALLOW_COPY_AND_ASSIGN(Mapper);
108};
109
110}  // namespace onc
111}  // namespace chromeos
112
113#endif  // CHROMEOS_NETWORK_ONC_ONC_MAPPER_H_
114