//
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// Copyright (C) 2012 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#ifndef UPDATE_ENGINE_COMMON_PREFS_H_
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#define UPDATE_ENGINE_COMMON_PREFS_H_
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#include <map>
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#include <string>
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#include <vector>
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#include <base/files/file_path.h>
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#include "gtest/gtest_prod.h" // for FRIEND_TEST
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#include "update_engine/common/prefs_interface.h"
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namespace chromeos_update_engine {
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// Implements a preference store by storing the value associated with a key
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// in a given storage passed during construction.
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class PrefsBase : public PrefsInterface {
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public:
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// Storage interface used to set and retrieve keys.
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class StorageInterface {
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public:
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StorageInterface() = default;
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virtual ~StorageInterface() = default;
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// Get the key named |key| and store its value in the referenced |value|.
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// Returns whether the operation succeeded.
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virtual bool GetKey(const std::string& key, std::string* value) const = 0;
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// Set the value of the key named |key| to |value| regardless of the
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// previous value. Returns whether the operation succeeded.
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virtual bool SetKey(const std::string& key, const std::string& value) = 0;
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// Returns whether the key named |key| exists.
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virtual bool KeyExists(const std::string& key) const = 0;
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// Deletes the value associated with the key name |key|. Returns whether the
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// key was deleted.
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virtual bool DeleteKey(const std::string& key) = 0;
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private:
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DISALLOW_COPY_AND_ASSIGN(StorageInterface);
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};
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explicit PrefsBase(StorageInterface* storage) : storage_(storage) {}
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// PrefsInterface methods.
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bool GetString(const std::string& key, std::string* value) const override;
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bool SetString(const std::string& key, const std::string& value) override;
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bool GetInt64(const std::string& key, int64_t* value) const override;
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bool SetInt64(const std::string& key, const int64_t value) override;
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bool GetBoolean(const std::string& key, bool* value) const override;
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bool SetBoolean(const std::string& key, const bool value) override;
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bool Exists(const std::string& key) const override;
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bool Delete(const std::string& key) override;
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void AddObserver(const std::string& key,
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ObserverInterface* observer) override;
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void RemoveObserver(const std::string& key,
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ObserverInterface* observer) override;
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private:
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// The registered observers watching for changes.
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std::map<std::string, std::vector<ObserverInterface*>> observers_;
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// The concrete implementation of the storage used for the keys.
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StorageInterface* storage_;
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DISALLOW_COPY_AND_ASSIGN(PrefsBase);
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};
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// Implements a preference store by storing the value associated with
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// a key in a separate file named after the key under a preference
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// store directory.
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class Prefs : public PrefsBase {
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public:
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Prefs() : PrefsBase(&file_storage_) {}
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// Initializes the store by associating this object with |prefs_dir|
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// as the preference store directory. Returns true on success, false
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// otherwise.
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bool Init(const base::FilePath& prefs_dir);
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private:
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FRIEND_TEST(PrefsTest, GetFileNameForKey);
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FRIEND_TEST(PrefsTest, GetFileNameForKeyBadCharacter);
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FRIEND_TEST(PrefsTest, GetFileNameForKeyEmpty);
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class FileStorage : public PrefsBase::StorageInterface {
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public:
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FileStorage() = default;
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bool Init(const base::FilePath& prefs_dir);
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// PrefsBase::StorageInterface overrides.
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bool GetKey(const std::string& key, std::string* value) const override;
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bool SetKey(const std::string& key, const std::string& value) override;
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bool KeyExists(const std::string& key) const override;
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bool DeleteKey(const std::string& key) override;
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private:
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FRIEND_TEST(PrefsTest, GetFileNameForKey);
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FRIEND_TEST(PrefsTest, GetFileNameForKeyBadCharacter);
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FRIEND_TEST(PrefsTest, GetFileNameForKeyEmpty);
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// Sets |filename| to the full path to the file containing the data
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// associated with |key|. Returns true on success, false otherwise.
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bool GetFileNameForKey(const std::string& key,
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base::FilePath* filename) const;
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// Preference store directory.
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base::FilePath prefs_dir_;
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};
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// The concrete file storage implementation.
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FileStorage file_storage_;
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DISALLOW_COPY_AND_ASSIGN(Prefs);
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};
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// Implements a preference store in memory. The stored values are lost when the
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// object is destroyed.
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class MemoryPrefs : public PrefsBase {
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public:
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MemoryPrefs() : PrefsBase(&mem_storage_) {}
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private:
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class MemoryStorage : public PrefsBase::StorageInterface {
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public:
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MemoryStorage() = default;
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// PrefsBase::StorageInterface overrides.
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bool GetKey(const std::string& key, std::string* value) const override;
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bool SetKey(const std::string& key, const std::string& value) override;
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bool KeyExists(const std::string& key) const override;
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bool DeleteKey(const std::string& key) override;
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private:
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// The std::map holding the values in memory.
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std::map<std::string, std::string> values_;
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};
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// The concrete memory storage implementation.
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MemoryStorage mem_storage_;
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DISALLOW_COPY_AND_ASSIGN(MemoryPrefs);
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};
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} // namespace chromeos_update_engine
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#endif // UPDATE_ENGINE_COMMON_PREFS_H_
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