xref: /foundation/distributeddatamgr/preferences/interfaces/inner_api/include/preferences_helper.h

/*
 * Copyright (c) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef PREFERENCES_HELPER_H
#define PREFERENCES_HELPER_H

#include <map>
#include <memory>
#include <mutex>
#include <string>

#include "preferences.h"

namespace OHOS {
namespace NativePreferences {
/**
 * The observer class of preferences. This class is used to obtain and delete preferences instances.
 */
class PREF_API_EXPORT PreferencesHelper {
public:

    /**
     * @brief Obtains a preferences instance matching a specified preferences file name.
     *
     * The preferences instance does not load data from the specified file every time. This is because if The
     * preferences instance is being used in another thread, it will be cached until it will no longer be used to and
     * performed {@link RemovePreferencesFromCache}.
     *
     * @param options Indicates the preferences configuration
     * @param errCode Indicates the error code. Returns 0 for success, others for failure.
     *
     * @return Returns a Preferences instance matching the specified preferences file name.
     */
    PREF_API_EXPORT static std::shared_ptr<Preferences> GetPreferences(const Options &options, int &errCode);

    /**
     * @brief Deletes a preferences instance matching a specified preferences file name.
     *
     * Calling this interface will delete both the preferences instance in the cache and the corresponding file on disk.
     * If you only want to remove preferences instances from cache, call interface {@link RemovePreferencesFromCache}.
     *
     * @param path Indicates the preferences file name.
     *
     * @return Returns 0 for success, others for failure.
     */
    PREF_API_EXPORT static int DeletePreferences(const std::string &path);

    /**
     * @brief Remove a preferences instance matching a specified preferences file name from cache.
     *
     * This function is used to remove a preferences instance matching a specified preferences file name from cache.
     *
     * @param path Indicates the preferences file name
     *
     * @return Returns 0 for success, others for failure.
     */
    PREF_API_EXPORT static int RemovePreferencesFromCache(const std::string &path);

private:
    // use bool to mark whether Preferences is EnhancePreferences or not
    static std::map<std::string, std::pair<std::shared_ptr<Preferences>, bool>> prefsCache_;
    static std::mutex prefsCacheMutex_;

    static std::string GetRealPath(const std::string &path, int &errorCode);
};
} // End of namespace NativePreferences
} // End of namespace OHOS
#endif // End of #ifndef PREFERENCES_HELPER_H