1// Copyright 2014 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 CHROME_BROWSER_PREFS_PREF_HASH_STORE_TRANSACTION_H_
6#define CHROME_BROWSER_PREFS_PREF_HASH_STORE_TRANSACTION_H_
7
8#include <string>
9#include <vector>
10
11namespace base {
12class DictionaryValue;
13class Value;
14}  // namespace base
15
16// Used to perform a series of checks/transformations on a PrefHashStore.
17class PrefHashStoreTransaction {
18 public:
19  enum ValueState {
20    // The preference value corresponds to its stored hash.
21    UNCHANGED,
22    // The preference has been cleared since the last hash.
23    CLEARED,
24    // The preference value corresponds to its stored hash, but the hash was
25    // calculated using a deprecated hash algorithm which is just as safe as
26    // the current one.
27    SECURE_LEGACY,
28    // The preference value has been changed since the last hash.
29    CHANGED,
30    // No stored hash exists for the preference value.
31    UNTRUSTED_UNKNOWN_VALUE,
32    // No stored hash exists for the preference value, but the current set of
33    // hashes stored is trusted and thus this value can safely be seeded. This
34    // happens when all hashes are already properly seeded and a newly
35    // tracked value needs to be seeded). NULL values are inherently trusted as
36    // well.
37    TRUSTED_UNKNOWN_VALUE,
38  };
39
40  // Finalizes any remaining work after the transaction has been performed.
41  virtual ~PrefHashStoreTransaction() {}
42
43  // Checks |initial_value| against the existing stored value hash.
44  virtual ValueState CheckValue(
45      const std::string& path, const base::Value* initial_value) const = 0;
46
47  // Stores a hash of the current |value| of the preference at |path|.
48  virtual void StoreHash(const std::string& path,
49                         const base::Value* value) = 0;
50
51  // Checks |initial_value| against the existing stored hashes for the split
52  // preference at |path|. |initial_split_value| being an empty dictionary or
53  // NULL is equivalent. |invalid_keys| must initially be empty. |invalid_keys|
54  // will not be modified unless the return value is CHANGED, in which case it
55  // will be filled with the keys that are considered invalid (unknown or
56  // changed).
57  virtual ValueState CheckSplitValue(
58      const std::string& path,
59      const base::DictionaryValue* initial_split_value,
60      std::vector<std::string>* invalid_keys) const = 0;
61
62  // Stores hashes for the |value| of the split preference at |path|.
63  // |split_value| being an empty dictionary or NULL is equivalent.
64  virtual void StoreSplitHash(
65      const std::string& path,
66      const base::DictionaryValue* split_value) = 0;
67
68  // Indicates whether the store contains a hash for the preference at |path|.
69  virtual bool HasHash(const std::string& path) const = 0;
70
71  // Sets the hash for the preference at |path|.
72  // If |path| is a split preference |hash| must be a DictionaryValue whose
73  // keys are keys in the split preference and whose values are MACs of the
74  // corresponding values in the split preference.
75  // If |path| is an atomic preference |hash| must be a StringValue
76  // containing a MAC of the preference value.
77  // |hash| should originate from a PrefHashStore sharing the same MAC
78  // parameters as this transaction's store.
79  // The (in)validity of the super MAC will be maintained by this call.
80  virtual void ImportHash(const std::string& path, const base::Value* hash) = 0;
81
82  // Removes the hash stored at |path|. The (in)validity of the super MAC will
83  // be maintained by this call.
84  virtual void ClearHash(const std::string& path) = 0;
85
86  // Indicates whether the super MAC was successfully verified at the beginning
87  // of this transaction.
88  virtual bool IsSuperMACValid() const = 0;
89
90  // Forces a valid super MAC to be stored when this transaction terminates.
91  // Returns true if this results in a change to the store contents.
92  virtual bool StampSuperMac() = 0;
93};
94
95#endif  // CHROME_BROWSER_PREFS_PREF_HASH_STORE_TRANSACTION_H_
96