base/prefs/writeable_pref_store.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 BASE_PREFS_WRITEABLE_PREF_STORE_H_
   6 #define BASE_PREFS_WRITEABLE_PREF_STORE_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/prefs/pref_store.h"
  12
  13 namespace base {
  14 class Value;
  15 }
  16
  17 // A pref store that can be written to as well as read from.
  18 class BASE_PREFS_EXPORT WriteablePrefStore : public PrefStore {
  19  public:
  20   WriteablePrefStore() {}
  21
  22   // Sets a |value| for |key| in the store. Assumes ownership of |value|, which
  23   // must be non-NULL.
  24   virtual void SetValue(const std::string& key, base::Value* value) = 0;
  25
  26   // Removes the value for |key|.
  27   virtual void RemoveValue(const std::string& key) = 0;
  28
  29   // Equivalent to PrefStore::GetValue but returns a mutable value.
  30   virtual bool GetMutableValue(const std::string& key,
  31                                base::Value** result) = 0;
  32
  33   // Triggers a value changed notification. This function needs to be called
  34   // if one retrieves a list or dictionary with GetMutableValue and change its
  35   // value. SetValue takes care of notifications itself. Note that
  36   // ReportValueChanged will trigger notifications even if nothing has changed.
  37   virtual void ReportValueChanged(const std::string& key) = 0;
  38
  39   // Same as SetValue, but doesn't generate notifications. This is used by
  40   // PrefService::GetMutableUserPref() in order to put empty entries
  41   // into the user pref store. Using SetValue is not an option since existing
  42   // tests rely on the number of notifications generated.
  43   virtual void SetValueSilently(const std::string& key, base::Value* value) = 0;
  44
  45  protected:
  46   virtual ~WriteablePrefStore() {}
  47
  48  private:
  49   DISALLOW_COPY_AND_ASSIGN(WriteablePrefStore);
  50 };
  51
  52 #endif  // BASE_PREFS_WRITEABLE_PREF_STORE_H_