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 <stdint.h> 9 10 #include <string> 11 12 #include "base/macros.h" 13 #include "base/memory/scoped_ptr.h" 14 #include "base/prefs/pref_store.h" 15 16 namespace base { 17 class Value; 18 } 19 20 // A pref store that can be written to as well as read from. 21 class BASE_PREFS_EXPORT WriteablePrefStore : public PrefStore { 22 public: 23 // PrefWriteFlags can be used to change the way a pref will be written to 24 // storage. 25 enum PrefWriteFlags : uint32_t { 26 // No flags are specified. 27 DEFAULT_PREF_WRITE_FLAGS = 0, 28 29 // This marks the pref as "lossy". There is no strict time guarantee on when 30 // a lossy pref will be persisted to permanent storage when it is modified. 31 LOSSY_PREF_WRITE_FLAG = 1 << 1 32 }; 33 WriteablePrefStore()34 WriteablePrefStore() {} 35 36 // Sets a |value| for |key| in the store. |value| must be non-NULL. |flags| is 37 // a bitmask of PrefWriteFlags. 38 virtual void SetValue(const std::string& key, 39 scoped_ptr<base::Value> value, 40 uint32_t flags) = 0; 41 42 // Removes the value for |key|. 43 virtual void RemoveValue(const std::string& key, uint32_t flags) = 0; 44 45 // Equivalent to PrefStore::GetValue but returns a mutable value. 46 virtual bool GetMutableValue(const std::string& key, 47 base::Value** result) = 0; 48 49 // Triggers a value changed notification. This function needs to be called 50 // if one retrieves a list or dictionary with GetMutableValue and change its 51 // value. SetValue takes care of notifications itself. Note that 52 // ReportValueChanged will trigger notifications even if nothing has changed. 53 // |flags| is a bitmask of PrefWriteFlags. 54 virtual void ReportValueChanged(const std::string& key, uint32_t flags) = 0; 55 56 // Same as SetValue, but doesn't generate notifications. This is used by 57 // PrefService::GetMutableUserPref() in order to put empty entries 58 // into the user pref store. Using SetValue is not an option since existing 59 // tests rely on the number of notifications generated. |flags| is a bitmask 60 // of PrefWriteFlags. 61 virtual void SetValueSilently(const std::string& key, 62 scoped_ptr<base::Value> value, 63 uint32_t flags) = 0; 64 65 protected: ~WriteablePrefStore()66 ~WriteablePrefStore() override {} 67 68 private: 69 DISALLOW_COPY_AND_ASSIGN(WriteablePrefStore); 70 }; 71 72 #endif // BASE_PREFS_WRITEABLE_PREF_STORE_H_ 73