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      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/compiler_specific.h"
     11 #include "base/macros.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 HashStoreContents;
     17 class PrefHashStoreTransaction;
     18 
     19 // Implements PrefHashStoreImpl by storing preference hashes in a
     20 // HashStoreContents.
     21 class PrefHashStoreImpl : public PrefHashStore {
     22  public:
     23   enum StoreVersion {
     24     // No hashes have been stored in this PrefHashStore yet.
     25     VERSION_UNINITIALIZED = 0,
     26     // The hashes in this PrefHashStore were stored before the introduction
     27     // of a version number and should be re-initialized.
     28     VERSION_PRE_MIGRATION = 1,
     29     // The hashes in this PrefHashStore were stored using the latest algorithm.
     30     VERSION_LATEST = 2,
     31   };
     32 
     33   // Constructs a PrefHashStoreImpl that calculates hashes using
     34   // |seed| and |device_id| and stores them in |contents|.
     35   //
     36   // The same |seed| and |device_id| must be used to load and validate
     37   // previously stored hashes in |contents|.
     38   PrefHashStoreImpl(const std::string& seed,
     39                     const std::string& device_id,
     40                     bool use_super_mac);
     41 
     42   virtual ~PrefHashStoreImpl();
     43 
     44   // Provides an external HashStoreContents implementation to be used.
     45   // BeginTransaction() will ignore |storage| if this is provided.
     46   void set_legacy_hash_store_contents(
     47       scoped_ptr<HashStoreContents> legacy_hash_store_contents);
     48 
     49   // Clears the contents of this PrefHashStore. |IsInitialized()| will return
     50   // false after this call.
     51   void Reset();
     52 
     53   // PrefHashStore implementation.
     54   virtual scoped_ptr<PrefHashStoreTransaction> BeginTransaction(
     55       scoped_ptr<HashStoreContents> storage) OVERRIDE;
     56 
     57  private:
     58   class PrefHashStoreTransactionImpl;
     59 
     60   const PrefHashCalculator pref_hash_calculator_;
     61   scoped_ptr<HashStoreContents> legacy_hash_store_contents_;
     62   bool use_super_mac_;
     63 
     64   DISALLOW_COPY_AND_ASSIGN(PrefHashStoreImpl);
     65 };
     66 
     67 #endif  // CHROME_BROWSER_PREFS_PREF_HASH_STORE_IMPL_H_
     68