1 // 2 // Copyright (C) 2012 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef UPDATE_ENGINE_COMMON_FAKE_PREFS_H_ 18 #define UPDATE_ENGINE_COMMON_FAKE_PREFS_H_ 19 20 #include <functional> 21 #include <map> 22 #include <string> 23 #include <string_view> 24 #include <vector> 25 26 #include <base/macros.h> 27 28 #include "update_engine/common/prefs_interface.h" 29 30 namespace chromeos_update_engine { 31 32 // Implements a fake preference store by storing the value associated with 33 // a key in a std::map, suitable for testing. It doesn't allow to set a value on 34 // a key with a different type than the previously set type. This enforces the 35 // type of a given key to be fixed. Also the class checks that the Get*() 36 // methods aren't called on a key set with a different type. 37 38 class FakePrefs : public PrefsInterface { 39 public: 40 FakePrefs() = default; 41 ~FakePrefs(); 42 43 // PrefsInterface methods. 44 bool GetString(std::string_view key, std::string* value) const override; 45 bool SetString(std::string_view key, std::string_view value) override; 46 bool GetInt64(std::string_view key, int64_t* value) const override; 47 bool SetInt64(std::string_view key, const int64_t value) override; 48 bool GetBoolean(std::string_view key, bool* value) const override; 49 bool SetBoolean(std::string_view key, const bool value) override; 50 51 bool Exists(std::string_view key) const override; 52 bool Delete(std::string_view key) override; 53 bool Delete(std::string_view key, 54 const std::vector<std::string>& nss) override; 55 56 bool GetSubKeys(std::string_view ns, 57 std::vector<std::string>* keys) const override; 58 59 void AddObserver(std::string_view key, ObserverInterface* observer) override; 60 void RemoveObserver(std::string_view key, 61 ObserverInterface* observer) override; 62 63 private: 64 enum class PrefType { 65 kString, 66 kInt64, 67 kBool, 68 }; 69 struct PrefValue { 70 std::string as_str; 71 int64_t as_int64; 72 bool as_bool; 73 }; 74 75 struct PrefTypeValue { 76 PrefType type; 77 PrefValue value; 78 }; 79 80 // Class to store compile-time type-dependent constants. 81 template <typename T> 82 class PrefConsts { 83 public: 84 // The PrefType associated with T. 85 static FakePrefs::PrefType const type; 86 87 // The data member pointer to PrefValue associated with T. 88 static T FakePrefs::PrefValue::*const member; 89 }; 90 91 // Returns a string representation of the PrefType useful for logging. 92 static std::string GetTypeName(PrefType type); 93 94 // Checks that the |key| is either not present or has the given |type|. 95 void CheckKeyType(std::string_view key, PrefType type) const; 96 97 // Helper function to set a value of the passed |key|. It sets the type based 98 // on the template parameter T. 99 template <typename T> 100 void SetValue(std::string_view key, T value); 101 102 // Helper function to get a value from the map checking for invalid calls. 103 // The function fails the test if you attempt to read a value defined as a 104 // different type. Returns whether the get succeeded. 105 template <typename T> 106 bool GetValue(std::string_view key, T* value) const; 107 108 // Container for all the key/value pairs. 109 std::map<std::string, PrefTypeValue, std::less<>> values_; 110 111 // The registered observers watching for changes. 112 std::map<std::string, std::vector<ObserverInterface*>, std::less<>> 113 observers_; 114 115 DISALLOW_COPY_AND_ASSIGN(FakePrefs); 116 }; 117 118 } // namespace chromeos_update_engine 119 120 #endif // UPDATE_ENGINE_COMMON_FAKE_PREFS_H_ 121