base/prefs/pref_value_map.h

   1 // Copyright (c) 2011 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_VALUE_MAP_H_
   6 #define BASE_PREFS_PREF_VALUE_MAP_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/containers/scoped_ptr_hash_map.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/prefs/base_prefs_export.h"
  15
  16 namespace base {
  17 class Value;
  18 }
  19
  20 // A generic string to value map used by the PrefStore implementations.
  21 class BASE_PREFS_EXPORT PrefValueMap {
  22  public:
  23   using Map = base::ScopedPtrHashMap<std::string, scoped_ptr<base::Value>>;
  24   using iterator = Map::iterator;
  25   using const_iterator = Map::const_iterator;
  26
  27   PrefValueMap();
  28   virtual ~PrefValueMap();
  29
  30   // Gets the value for |key| and stores it in |value|. Ownership remains with
  31   // the map. Returns true if a value is present. If not, |value| is not
  32   // touched.
  33   bool GetValue(const std::string& key, const base::Value** value) const;
  34   bool GetValue(const std::string& key, base::Value** value);
  35
  36   // Sets a new |value| for |key|. |value| must be non-null. Returns true if the
  37   // value changed.
  38   bool SetValue(const std::string& key, scoped_ptr<base::Value> value);
  39
  40   // Removes the value for |key| from the map. Returns true if a value was
  41   // removed.
  42   bool RemoveValue(const std::string& key);
  43
  44   // Clears the map.
  45   void Clear();
  46
  47   // Swaps the contents of two maps.
  48   void Swap(PrefValueMap* other);
  49
  50   iterator begin();
  51   iterator end();
  52   const_iterator begin() const;
  53   const_iterator end() const;
  54
  55   // Gets a boolean value for |key| and stores it in |value|. Returns true if
  56   // the value was found and of the proper type.
  57   bool GetBoolean(const std::string& key, bool* value) const;
  58
  59   // Sets the value for |key| to the boolean |value|.
  60   void SetBoolean(const std::string& key, bool value);
  61
  62   // Gets a string value for |key| and stores it in |value|. Returns true if
  63   // the value was found and of the proper type.
  64   bool GetString(const std::string& key, std::string* value) const;
  65
  66   // Sets the value for |key| to the string |value|.
  67   void SetString(const std::string& key, const std::string& value);
  68
  69   // Gets an int value for |key| and stores it in |value|. Returns true if
  70   // the value was found and of the proper type.
  71   bool GetInteger(const std::string& key, int* value) const;
  72
  73   // Sets the value for |key| to the int |value|.
  74   void SetInteger(const std::string& key, const int value);
  75
  76   // Sets the value for |key| to the double |value|.
  77   void SetDouble(const std::string& key, const double value);
  78
  79   // Compares this value map against |other| and stores all key names that have
  80   // different values in |differing_keys|. This includes keys that are present
  81   // only in one of the maps.
  82   void GetDifferingKeys(const PrefValueMap* other,
  83                         std::vector<std::string>* differing_keys) const;
  84
  85  private:
  86   Map prefs_;
  87
  88   DISALLOW_COPY_AND_ASSIGN(PrefValueMap);
  89 };
  90
  91 #endif  // BASE_PREFS_PREF_VALUE_MAP_H_