/*
 * Copyright (c) 2020 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.
 */

/**
 * @addtogroup AbilityKit
 * @{
 *
 * @brief Provides ability-related functions, including ability lifecycle callbacks and functions for connecting to or
 *        disconnecting from Particle Abilities.
 *
 * Abilities are classified into Feature Abilities and Particle Abilities. Feature Abilities support the Page template,
 * and Particle Abilities support the Service template. An ability using the Page template is called a Page ability for
 * short and that using the Service template is called a Service ability.
 *
 * @since 1.0
 * @version 1.0
 */

/**
 * @file ability_event_handler.h
 *
 * @brief Declares functions for performing operations during inter-thread communication, including running and
 *        quitting the event loop of the current thread and posting tasks to an asynchronous thread.
 *
 * @since 1.0
 * @version 1.0
 */

#ifndef OHOS_ABILITY_EVENT_HANDLER_H
#define OHOS_ABILITY_EVENT_HANDLER_H

#include <functional>
#include <pthread.h>
#include <queue>

namespace OHOS {
/**
 * @brief Declares functions for performing operations during inter-thread communication, including running and
 *        quitting the event loop of the current thread and posting tasks to an asynchronous thread.
 *
 * @since 1.0
 * @version 1.0
 */
class AbilityEventHandler {
public:
    using Task = std::function<void()>;

    AbilityEventHandler();
    ~AbilityEventHandler();

    /**
     * @brief Starts running the event loop of the current thread.
     */
    void Run();

    /**
     * @brief Posts a task to an asynchronous thread.
     *
     * @param task Indicates the task to post.
     */
    void PostTask(const Task &task);

    /**
     * @brief Quits the event loop of the current thread.
     */
    void PostQuit();

    /**
     * @brief Obtains the event handler of the current thread.
     *
     * @return Returns the pointer to the {@link AbilityEventHandler} object of the current thread.
     */
    static AbilityEventHandler* GetCurrentHandler();
private:
    std::queue<Task> taskQueue_;

    pthread_cond_t pthreadCond_ = PTHREAD_COND_INITIALIZER;
    pthread_mutex_t queueMutex_ = PTHREAD_MUTEX_INITIALIZER;

    bool quit_ { false };

    AbilityEventHandler(const AbilityEventHandler&) = delete;
    AbilityEventHandler& operator = (const AbilityEventHandler&) = delete;
    AbilityEventHandler(AbilityEventHandler&&) = delete;
    AbilityEventHandler& operator= (AbilityEventHandler&&) = delete;
};
}  // namespace OHOS
#endif  // OHOS_ABILITY_EVENT_HANDLER_H