* continue_with.h
* Copyright (C) 2014 Ivan Čukić <ivan.cukic(at)kde.org>
*
* Distributed under terms of the MIT license.
*/
#ifndef UTILS_CONTINUE_WITH_H
#define UTILS_CONTINUE_WITH_H
#include <QFuture>
#include <QFutureWatcher>
#include <QDebug>
#include <boost/optional.hpp>
#ifdef ENABLE_QJSVALUE_CONTINUATION
#include <QJSValue>
#endif
namespace kamd {
namespace utils {
namespace detail {
#ifdef ENABLE_QJSVALUE_CONTINUATION
inline void test_continuation(const QJSValue &continuation)
{
if (!continuation.isCallable()) {
qWarning() << "Passed handler is not callable: " << continuation.toString();
}
}
template <typename _ReturnType>
inline void pass_value(const QFuture<_ReturnType> &future,
QJSValue continuation)
{
auto result = continuation.call({ future.result() });
if (result.isError()) {
qWarning() << "Handler returned this error: " << result.toString();
}
}
inline void pass_value(const QFuture<void> &future, QJSValue continuation)
{
Q_UNUSED(future);
auto result = continuation.call({});
if (result.isError()) {
qWarning() << "Handler returned this error: " << result.toString();
}
}
#endif
template <typename _Continuation>
inline void test_continuation(_Continuation &&continuation)
{
Q_UNUSED(continuation);
}
template <typename _ReturnType, typename _Continuation>
inline void pass_value(const QFuture<_ReturnType> &future,
_Continuation &&continuation)
{
continuation(future.resultCount() > 0
? boost::make_optional(future.result())
: boost::none);
}
template <typename _Continuation>
inline void pass_value(_Continuation &&continuation)
{
continuation();
}
}
template <typename _ReturnType, typename _Continuation>
inline void continue_with(const QFuture<_ReturnType> &future,
_Continuation &&continuation)
{
detail::test_continuation(continuation);
auto watcher = new QFutureWatcher<_ReturnType>();
QObject::connect(watcher, &QFutureWatcherBase::finished, [=]() mutable {
detail::pass_value(future, continuation);
});
watcher->setFuture(future);
}
}
}
#endif
