components/pref_registry/pref_registry_syncable.h

   1 // Copyright (c) 2012 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_PREF_REGISTRY_PREF_REGISTRY_SYNCABLE_H_
   6 #define COMPONENTS_PREF_REGISTRY_PREF_REGISTRY_SYNCABLE_H_
   7
   8 #include <string>
   9
  10 #include "base/callback.h"
  11 #include "base/prefs/pref_registry_simple.h"
  12
  13 namespace base {
  14 class DictionaryValue;
  15 class FilePath;
  16 class ListValue;
  17 class Value;
  18 }
  19
  20 // TODO(tfarina): Change this namespace to pref_registry.
  21 namespace user_prefs {
  22
  23 // A PrefRegistry that forces users to choose whether each registered
  24 // preference is syncable or not.
  25 //
  26 // Classes or components that want to register such preferences should
  27 // define a static function named RegisterUserPrefs that takes a
  28 // PrefRegistrySyncable*, and the top-level application using the
  29 // class or embedding the component should call this function at an
  30 // appropriate time before the PrefService for these preferences is
  31 // constructed. See e.g. chrome/browser/prefs/browser_prefs.cc which
  32 // does this for Chrome.
  33 //
  34 // TODO(raymes): This class only exists to support SyncableRegistrationCallback
  35 // logic which is only required to support pref registration after the
  36 // PrefService has been created which is only used by tests. We can remove this
  37 // entire class and those tests with some work.
  38 class PrefRegistrySyncable : public PrefRegistrySimple {
  39  public:
  40   // Enum of flags used when registering preferences to determine if it should
  41   // be synced or not. These flags are mutually exclusive, only one of them
  42   // should ever be specified.
  43   //
  44   // Note: These must NOT overlap with PrefRegistry::PrefRegistrationFlags.
  45   enum PrefRegistrationFlags : uint32 {
  46     // The pref will be synced.
  47     SYNCABLE_PREF = 1 << 0,
  48
  49     // The pref will be synced. The pref will never be encrypted and will be
  50     // synced before other datatypes. Because they're never encrypted, on first
  51     // sync, they can be synced down before the user is prompted for a
  52     // passphrase.
  53     SYNCABLE_PRIORITY_PREF = 1 << 1,
  54   };
  55
  56   typedef base::Callback<void(const std::string& path, uint32 flags)>
  57       SyncableRegistrationCallback;
  58
  59   PrefRegistrySyncable();
  60
  61   // Exactly one callback can be set for the event of a syncable
  62   // preference being registered. It will be fired after the
  63   // registration has occurred.
  64   //
  65   // Calling this method after a callback has already been set will
  66   // make the object forget the previous callback and use the new one
  67   // instead.
  68   void SetSyncableRegistrationCallback(const SyncableRegistrationCallback& cb);
  69
  70   // Returns a new PrefRegistrySyncable that uses the same defaults
  71   // store.
  72   scoped_refptr<PrefRegistrySyncable> ForkForIncognito();
  73
  74  private:
  75   ~PrefRegistrySyncable() override;
  76
  77   // PrefRegistrySimple overrides.
  78   void OnPrefRegistered(const std::string& path,
  79                         base::Value* default_value,
  80                         uint32 flags) override;
  81
  82   SyncableRegistrationCallback callback_;
  83
  84   DISALLOW_COPY_AND_ASSIGN(PrefRegistrySyncable);
  85 };
  86
  87 }  // namespace user_prefs
  88
  89 #endif  // COMPONENTS_PREF_REGISTRY_PREF_REGISTRY_SYNCABLE_H_