ClickHouse/contrib/libpoco/Foundation/include/Poco/TaskManager.h
2016-08-26 22:55:11 +03:00

140 lines
3.4 KiB
C++

//
// TaskManager.h
//
// $Id: //poco/1.4/Foundation/include/Poco/TaskManager.h#2 $
//
// Library: Foundation
// Package: Tasks
// Module: Tasks
//
// Definition of the TaskManager class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_TaskManager_INCLUDED
#define Foundation_TaskManager_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Mutex.h"
#include "Poco/Task.h"
#include "Poco/AutoPtr.h"
#include "Poco/NotificationCenter.h"
#include "Poco/Timestamp.h"
#include <list>
namespace Poco {
class Notification;
class ThreadPool;
class Exception;
class Foundation_API TaskManager
/// The TaskManager manages a collection of tasks
/// and monitors their lifetime.
///
/// A TaskManager has a built-in NotificationCenter that
/// is used to send out notifications on task progress
/// and task states. See the TaskNotification class and its
/// subclasses for the various events that result in a notification.
/// To keep the number of notifications small, a TaskProgressNotification
/// will only be sent out once in 100 milliseconds.
{
public:
typedef AutoPtr<Task> TaskPtr;
typedef std::list<TaskPtr> TaskList;
TaskManager();
/// Creates the TaskManager, using the
/// default ThreadPool.
TaskManager(ThreadPool& pool);
/// Creates the TaskManager, using the
/// given ThreadPool.
~TaskManager();
/// Destroys the TaskManager.
void start(Task* pTask);
/// Starts the given task in a thread obtained
/// from the thread pool.
///
/// The TaskManager takes ownership of the Task object
/// and deletes it when it it finished.
void cancelAll();
/// Requests cancellation of all tasks.
void joinAll();
/// Waits for the completion of all the threads
/// in the TaskManager's thread pool.
///
/// Note: joinAll() will wait for ALL tasks in the
/// TaskManager's ThreadPool to complete. If the
/// ThreadPool has threads created by other
/// facilities, these threads must also complete
/// before joinAll() can return.
TaskList taskList() const;
/// Returns a copy of the internal task list.
int count() const;
/// Returns the number of tasks in the internal task list.
void addObserver(const AbstractObserver& observer);
/// Registers an observer with the NotificationCenter.
/// Usage:
/// Observer<MyClass, MyNotification> obs(*this, &MyClass::handleNotification);
/// notificationCenter.addObserver(obs);
void removeObserver(const AbstractObserver& observer);
/// Unregisters an observer with the NotificationCenter.
static const int MIN_PROGRESS_NOTIFICATION_INTERVAL;
protected:
void postNotification(const Notification::Ptr& pNf);
/// Posts a notification to the task manager's
/// notification center.
void taskStarted(Task* pTask);
void taskProgress(Task* pTask, float progress);
void taskCancelled(Task* pTask);
void taskFinished(Task* pTask);
void taskFailed(Task* pTask, const Exception& exc);
private:
ThreadPool& _threadPool;
TaskList _taskList;
Timestamp _lastProgressNotification;
NotificationCenter _nc;
mutable FastMutex _mutex;
friend class Task;
};
//
// inlines
//
inline int TaskManager::count() const
{
FastMutex::ScopedLock lock(_mutex);
return static_cast<int>(_taskList.size());
}
} // namespace Poco
#endif // Foundation_TaskManager_INCLUDED