chrome/browser/prefs/pref_hash_calculator.h

   1 // Copyright 2013 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_CALCULATOR_H_
   6 #define CHROME_BROWSER_PREFS_PREF_HASH_CALCULATOR_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11
  12 namespace base {
  13 class Value;
  14 }  // namespace base
  15
  16 // Calculates and validates preference value hashes.
  17 class PrefHashCalculator {
  18  public:
  19   enum ValidationResult {
  20     INVALID,
  21     VALID,
  22     VALID_LEGACY,
  23   };
  24
  25   // Constructs a PrefHashCalculator using |seed| and |device_id|. The same
  26   // parameters must be used in order to successfully validate generated hashes.
  27   // |device_id| may be empty.
  28   PrefHashCalculator(const std::string& seed, const std::string& device_id);
  29
  30   // Calculates a hash value for the supplied preference |path| and |value|.
  31   // |value| may be null if the preference has no value.
  32   std::string Calculate(const std::string& path, const base::Value* value)
  33       const;
  34
  35   // Validates the provided preference hash using current and legacy hashing
  36   // algorithms.
  37   ValidationResult Validate(const std::string& path,
  38                             const base::Value* value,
  39                             const std::string& hash) const;
  40
  41  private:
  42   // Concatenates |device_id_|, |path|, and |value| to give the hash input.
  43   std::string GetMessage(const std::string& path,
  44                          const base::Value* value) const;
  45
  46   std::string seed_;
  47   std::string device_id_;
  48
  49   DISALLOW_COPY_AND_ASSIGN(PrefHashCalculator);
  50 };
  51
  52 #endif  // CHROME_BROWSER_PREFS_PREF_HASH_CALCULATOR_H_