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oak-editor/app/task/taskmanager.h
T
2019-06-27 11:23:17 -07:00

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/***
Olive - Non-Linear Video Editor
Copyright (C) 2019 Olive Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
***/
#ifndef TASKMANAGER_H
#define TASKMANAGER_H
#include <QVector>
#include "task/task.h"
/**
* @brief The TaskManager class
*
* TaskManager handles the life of a Task object. After a new Task is created, it should be sent to TaskManager through
* AddTask(). TaskManager will take ownership of the task and add it to a queue until it system resources are available
* for it to run. Currently, TaskManager will run no more Tasks than there are threads on the system (one task per
* thread). As Tasks finished, TaskManager will start the next in the queue.
*/
class TaskManager : public QObject
{
Q_OBJECT
public:
/**
* @brief TaskManager Constructor
*/
TaskManager();
/**
* @brief Add a new Task
*
* Adds a new Task to the queue. If there are available threads to run it, it'll also run immediately. Otherwise,
* it'll be placed into the queue and run when resources are available.
*
* NOTE: This function is NOT thread-safe and is currently intended to only be used from the main/GUI thread.
*
* @param t
*
* The task to add and run. TaskManager takes ownership of this Task and will be responsible for freeing it.
*/
void AddTask(Task *t);
private:
/**
* @brief Scan through the task queue and start any Tasks that are able to start
*
* This function is run whenever a Task is added and whenever a Task finishes. It determines how many Tasks are
* currently running and therefore how many Tasks can be started (if any). It will then start ones that can.
*
* Like AddTask, this function is NOT thread-safe and currently only intended to be run from the main thread.
*/
void StartNextWaiting();
/**
* @brief Internal task array
*/
QVector<Task*> tasks_;
/**
* @brief Constant set at run-time of how many Tasks can run concurrently
*
* Currently set in the Constructor to QThread::idealThreadCount()
*/
int maximum_task_count_;
private slots:
/**
* @brief Callback when a Task's status changes
*
* When a Task is added, it's connected to this so TaskManager is alerted whenever a Task's status changes. It can
* therefore keep track of Tasks starting, completing, or failing.
*
* @param status
*
* The new status of the Task
*/
void TaskCallback(Task::Status status);
};
namespace olive {
extern TaskManager task_manager;
}
#endif // TASKMANAGER_H