1 // Copyright 2014 The Chromium Authors 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 COMPONENTS_PREFS_WRITEABLE_PREF_STORE_H_ 6 #define COMPONENTS_PREFS_WRITEABLE_PREF_STORE_H_ 7 8 #include <stdint.h> 9 10 #include <memory> 11 #include <set> 12 #include <string> 13 #include <string_view> 14 #include <vector> 15 16 #include "components/prefs/pref_store.h" 17 18 namespace base { 19 class Value; 20 } 21 22 // A pref store that can be written to as well as read from. 23 class COMPONENTS_PREFS_EXPORT WriteablePrefStore : public PrefStore { 24 public: 25 // PrefWriteFlags can be used to change the way a pref will be written to 26 // storage. 27 enum PrefWriteFlags : uint32_t { 28 // No flags are specified. 29 DEFAULT_PREF_WRITE_FLAGS = 0, 30 31 // This marks the pref as "lossy". There is no strict time guarantee on when 32 // a lossy pref will be persisted to permanent storage when it is modified. 33 LOSSY_PREF_WRITE_FLAG = 1 << 1 34 }; 35 36 WriteablePrefStore() = default; 37 38 WriteablePrefStore(const WriteablePrefStore&) = delete; 39 WriteablePrefStore& operator=(const WriteablePrefStore&) = delete; 40 41 // Sets a `value` for `key` in the store. `flags` is a bitmask of 42 // PrefWriteFlags. 43 virtual void SetValue(std::string_view key, 44 base::Value value, 45 uint32_t flags) = 0; 46 47 // Removes the value for `key`. `flags` is a bitmask of 48 // PrefWriteFlags. 49 virtual void RemoveValue(std::string_view key, uint32_t flags) = 0; 50 51 // Equivalent to PrefStore::GetValue but returns a mutable value. 52 virtual bool GetMutableValue(std::string_view key, base::Value** result) = 0; 53 54 // Triggers a value changed notification. This function or 55 // ReportSubValuesChanged needs to be called if one retrieves a list or 56 // dictionary with GetMutableValue and change its value. SetValue takes care 57 // of notifications itself. Note that ReportValueChanged will trigger 58 // notifications even if nothing has changed. `flags` is a bitmask of 59 // PrefWriteFlags. 60 virtual void ReportValueChanged(std::string_view key, uint32_t flags) = 0; 61 62 // Triggers a value changed notification for `path_components` in the `key` 63 // pref. This function or ReportValueChanged needs to be called if one 64 // retrieves a list or dictionary with GetMutableValue and change its value. 65 // SetValue takes care of notifications itself. Note that 66 // ReportSubValuesChanged will trigger notifications even if nothing has 67 // changed. `flags` is a bitmask of PrefWriteFlags. 68 virtual void ReportSubValuesChanged( 69 std::string_view key, 70 std::set<std::vector<std::string>> path_components, 71 uint32_t flags); 72 73 // Same as SetValue, but doesn't generate notifications. This is used by 74 // PrefService::GetMutableUserPref() in order to put empty entries 75 // into the user pref store. Using SetValue is not an option since existing 76 // tests rely on the number of notifications generated. `flags` is a bitmask 77 // of PrefWriteFlags. 78 virtual void SetValueSilently(std::string_view key, 79 base::Value value, 80 uint32_t flags) = 0; 81 82 // Clears all the preferences which names start with `prefix` and doesn't 83 // generate update notifications. 84 virtual void RemoveValuesByPrefixSilently(std::string_view prefix) = 0; 85 86 protected: 87 ~WriteablePrefStore() override = default; 88 }; 89 90 #endif // COMPONENTS_PREFS_WRITEABLE_PREF_STORE_H_ 91