components/user_prefs/tracked/hash_store_contents.h

   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 COMPONENTS_USER_PREFS_TRACKED_HASH_STORE_CONTENTS_H_
   6 #define COMPONENTS_USER_PREFS_TRACKED_HASH_STORE_CONTENTS_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11
  12 namespace base {
  13 class DictionaryValue;
  14 }  // namespace base
  15
  16 // Provides access to the contents of a preference hash store. The store
  17 // contains the following data:
  18 // Contents: a client-defined dictionary that should map preference names to
  19 // MACs.
  20 // Version: a client-defined version number for the format of Contents.
  21 // Super MAC: a MAC that authenticates the entirety of Contents.
  22 // Legacy hash stores may have an ID that was incorporated into MAC
  23 // calculations. The ID, if any, is available via |hash_store_id()|.
  24 class HashStoreContents {
  25  public:
  26   // Used to modify a DictionaryValue stored in the preference hash store. The
  27   // MutableDictionary should be destroyed when modifications are complete in
  28   // order to allow them to be committed to the underlying storage.
  29   class MutableDictionary {
  30    public:
  31     virtual ~MutableDictionary() {}
  32     // Returns the DictionaryValue, which will be created if it does not already
  33     // exist.
  34     virtual base::DictionaryValue* operator->() = 0;
  35   };
  36
  37   virtual ~HashStoreContents() {}
  38
  39   // Returns the hash-store ID. May be empty.
  40   virtual std::string hash_store_id() const = 0;
  41
  42   // Discards all data related to this hash store.
  43   virtual void Reset() = 0;
  44
  45   // Indicates whether any data is currently stored for this hash store.
  46   virtual bool IsInitialized() const = 0;
  47
  48   // Retrieves the contents of this hash store. May return NULL if the hash
  49   // store has not been initialized.
  50   virtual const base::DictionaryValue* GetContents() const = 0;
  51
  52   // Provides mutable access to the contents of this hash store.
  53   virtual scoped_ptr<MutableDictionary> GetMutableContents() = 0;
  54
  55   // Retrieves the super MAC value previously stored by SetSuperMac. May be
  56   // empty if no super MAC has been stored.
  57   virtual std::string GetSuperMac() const = 0;
  58
  59   // Stores a super MAC value for this hash store.
  60   virtual void SetSuperMac(const std::string& super_mac) = 0;
  61 };
  62
  63 #endif  // COMPONENTS_USER_PREFS_TRACKED_HASH_STORE_CONTENTS_H_