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/*
* Copyright 2014 Daniel Vrátil <dvratil@redhat.com>
*
* 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 2 of
* the License or (at your option) version 3 or any later version
* accepted by the membership of KDE e.V. (or its successor approved
* by the membership of KDE e.V.), which shall act as a proxy
* defined in Section 14 of version 3 of the license.
*
* 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 ASYNC_H
#define ASYNC_H
#include <functional>
#include <list>
#include <type_traits>
#include <iostream>
#include <cassert>
#include "future.h"
#include "async_impl.h"
namespace Async {
class JobBase;
template<typename Out, typename ... In>
class Job;
template<typename Out, typename ... In>
using ThenTask = typename detail::identity<std::function<void(In ..., Async::Future<Out>&)>>::type;
template<typename Out, typename In>
using EachTask = typename detail::identity<std::function<void(In, Async::Future<Out>&)>>::type;
template<typename Out, typename In>
using ReduceTask = typename detail::identity<std::function<void(In, Async::Future<Out>&)>>::type;
template<typename Out, typename ... In>
Job<Out, In ...> start(ThenTask<Out, In ...> func);
namespace Private
{
template<typename Out, typename ... In>
void doExec(Job<Out, In ...> *job, Async::Future<Out> &out, const In & ... args);
}
class JobBase
{
template<typename Out, typename ... In>
friend class Job;
protected:
enum JobType {
Then,
Each,
Reduce
};
public:
JobBase(JobType jobType, JobBase *prev = nullptr);
virtual void exec() = 0;
protected:
JobBase *mPrev;
void *mResult;
JobType mJobType;
};
template<typename Out, typename ... In>
class Job : public JobBase
{
template<typename Out_, typename ... In_>
friend class Job;
template<typename Out_, typename ... In_>
friend Job<Out_, In_ ...> start(Async::ThenTask<Out_, In_ ...> func);
typedef Out OutType;
typedef typename std::tuple_element<0, std::tuple<In ..., void>>::type InType;
public:
~Job()
{
delete reinterpret_cast<Async::Future<Out>*>(mResult);
}
template<typename Out_, typename ... In_>
Job<Out_, In_ ...> then(ThenTask<Out_, In_ ...> func)
{
return Job<Out_, In_ ...>::create(func, JobBase::Then, this);
}
template<typename Out_, typename In_>
Job<Out_, In_> each(EachTask<Out_, In_> func)
{
static_assert(detail::isIterable<OutType>::value,
"The 'Each' task can only be connected to a job that returns a list or array.");
static_assert(detail::isIterable<Out_>::value,
"The result type of 'Each' task must be a list or an array.");
return Job<Out_, In_>::create(func, JobBase::Each, this);
}
template<typename Out_, typename In_>
Job<Out_, In_> reduce(ReduceTask<Out_, In_> func)
{
static_assert(Async::detail::isIterable<OutType>::value,
"The result type of 'Reduce' task must be a list or an array.");
return Job<Out_, In_>::create(func, JobBase::Reduce, this);
}
Async::Future<Out> result() const
{
return *reinterpret_cast<Async::Future<Out>*>(mResult);
}
void exec();
private:
Job(JobBase::JobType jobType, JobBase *parent = nullptr)
: JobBase(jobType, parent)
{
}
template<typename F>
static Job<Out, In ... > create(F func, JobBase::JobType jobType, JobBase *parent = nullptr);
public:
std::function<void(In ..., Async::Future<Out>&)> mFunc;
};
} // namespace Async
// ********** Out of line definitions ****************
template<typename Out, typename ... In>
Async::Job<Out, In ...> Async::start(ThenTask<Out, In ...> func)
{
return Job<Out, In ...>::create(func, JobBase::Then);
}
template<typename Out, typename ... In>
void Async::Private::doExec(Job<Out, In ...> *job, Async::Future<Out> &out, const In & ... args)
{
job->mFunc(args ..., out);
};
template<typename Out, typename ... In>
void Async::Job<Out, In ...>::exec()
{
Async::Future<InType> *in = nullptr;
if (mPrev) {
mPrev->exec();
in = reinterpret_cast<Async::Future<InType>*>(mPrev->mResult);
assert(in->isFinished());
}
auto out = new Async::Future<Out>();
Private::doExec<Out, In ...>(this, *out, in ? in->value() : In() ...);
out->waitForFinished();
mResult = reinterpret_cast<void*>(out);
}
template<typename Out, typename ... In>
template<typename F>
Async::Job<Out, In ...> Async::Job<Out, In ...>::create(F func, Async::JobBase::JobType jobType, Async::JobBase* parent)
{
Job<Out, In ...> job(jobType, parent);
job.mFunc = func;
return job;
}
#endif // ASYNC_H
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