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