base/prefs/pref_registry.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 BASE_PREFS_PREF_REGISTRY_H_
   6 #define BASE_PREFS_PREF_REGISTRY_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "base/prefs/base_prefs_export.h"
  10 #include "base/prefs/pref_value_map.h"
  11
  12 namespace base {
  13 class Value;
  14 }
  15
  16 class DefaultPrefStore;
  17 class PrefStore;
  18
  19 // Preferences need to be registered with a type and default value
  20 // before they are used.
  21 //
  22 // The way you use a PrefRegistry is that you register all required
  23 // preferences on it (via one of its subclasses), then pass it as a
  24 // construction parameter to PrefService.
  25 //
  26 // Currently, registrations after constructing the PrefService will
  27 // also work, but this is being deprecated.
  28 class BASE_PREFS_EXPORT PrefRegistry : public base::RefCounted<PrefRegistry> {
  29  public:
  30   typedef PrefValueMap::const_iterator const_iterator;
  31
  32   PrefRegistry();
  33
  34   // Gets the registered defaults.
  35   scoped_refptr<PrefStore> defaults();
  36
  37   // Allows iteration over defaults.
  38   const_iterator begin() const;
  39   const_iterator end() const;
  40
  41   // Changes the default value for a preference. Takes ownership of |value|.
  42   //
  43   // |pref_name| must be a previously registered preference.
  44   void SetDefaultPrefValue(const std::string& pref_name, base::Value* value);
  45
  46  protected:
  47   friend class base::RefCounted<PrefRegistry>;
  48   virtual ~PrefRegistry();
  49
  50   // Used by subclasses to register a default value for a preference.
  51   void RegisterPreference(const std::string& path, base::Value* default_value);
  52
  53   scoped_refptr<DefaultPrefStore> defaults_;
  54
  55  private:
  56   DISALLOW_COPY_AND_ASSIGN(PrefRegistry);
  57 };
  58
  59 #endif  // BASE_PREFS_PREF_REGISTRY_H_