#include "QueuedBackgroundTask.h"
#include "ScopeGuard.h"

//void QueuedBackgroundTask::requestPause()
//{}

QueuedBackgroundTask::QueuedBackgroundTask(CompletionFunction on_completion)
	: m_completionFunction(on_completion)
{
	setAutoDelete(false);
}

QueuedBackgroundTask::~QueuedBackgroundTask()
{
	cancel();
	wait();
}

void QueuedBackgroundTask::cancel()
{
	QMutexLocker lock(&stateMutex);
	if (!m_finished)
		m_canceled = true;
}

void QueuedBackgroundTask::wait()
{
	QMutexLocker lock(&stateMutex);
	if (!m_finished)
		finished.wait(&stateMutex);
}

bool QueuedBackgroundTask::hasException() const
{
	return doRunException != nullptr;
}

void QueuedBackgroundTask::rethrow()
{
	std::rethrow_exception(doRunException);
}

void QueuedBackgroundTask::run()
{
	SCOPE_EXIT {
		m_finished = true;
		QMutexLocker lock(&stateMutex);
		finished.notify_all();
	};
	QMutexLocker lock(&stateMutex);
	m_started = true;
	if (!m_canceled) {
		lock.unlock();
		try {
			doRun();
		}
		catch (...) {
			doRunException = std::current_exception();
		}

		if (!m_canceled && m_completionFunction)
			m_completionFunction(this);
	}
}