chrome/browser/prefs/pref_hash_store_impl.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_STORE_IMPL_H_
   6 #define CHROME_BROWSER_PREFS_PREF_HASH_STORE_IMPL_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "chrome/browser/prefs/pref_hash_calculator.h"
  14 #include "chrome/browser/prefs/pref_hash_store.h"
  15
  16 class PrefRegistrySimple;
  17 class PrefService;
  18
  19 namespace base {
  20 class Value;
  21 }  // namespace base
  22
  23 // Implements PrefHashStoreImpl by storing preference hashes in a PrefService.
  24 class PrefHashStoreImpl : public PrefHashStore {
  25  public:
  26   // Constructs a PrefHashStoreImpl that calculates hashes using
  27   // |seed| and |device_id| and stores them in |local_state|. Multiple hash
  28   // stores can use the same |local_state| with distinct |hash_store_id|s.
  29   //
  30   // The same |seed|, |device_id|, and |hash_store_id| must be used to load and
  31   // validate previously stored hashes in |local_state|.
  32   //
  33   // |local_state| must have previously been passed to |RegisterPrefs|.
  34   PrefHashStoreImpl(const std::string& hash_store_id,
  35                     const std::string& seed,
  36                     const std::string& device_id,
  37                     PrefService* local_state);
  38
  39   // Registers required local state preferences.
  40   static void RegisterPrefs(PrefRegistrySimple* registry);
  41
  42   // PrefHashStore implementation.
  43   virtual ValueState CheckValue(const std::string& path,
  44                                 const base::Value* value) const OVERRIDE;
  45   virtual void StoreHash(const std::string& path,
  46                          const base::Value* value) OVERRIDE;
  47
  48  private:
  49   // Returns true if the dictionary of hashes stored for |hash_store_id_| is
  50   // trusted (which implies unknown values can be trusted as newly tracked
  51   // values).
  52   bool IsHashDictionaryTrusted() const;
  53
  54   std::string hash_store_id_;
  55   PrefHashCalculator pref_hash_calculator_;
  56   PrefService* local_state_;
  57   bool initial_hashes_dictionary_trusted_;
  58
  59   DISALLOW_COPY_AND_ASSIGN(PrefHashStoreImpl);
  60 };
  61
  62 #endif  // CHROME_BROWSER_PREFS_PREF_HASH_STORE_IMPL_H_