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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 {
template<typename Out, typename ... In>
class Job;
template<typename Out, typename ... In>
Job<Out, In ...> start(const std::function<Async::Future<Out>(In ...)> &func);
class JobBase
{
public:
JobBase(JobBase *prev = nullptr)
: mPrev(prev)
, mResult(0)
{}
virtual void exec() = 0;
public:
JobBase *mPrev;
void *mResult;
};
namespace Private {
template<typename Out, typename In>
typename std::enable_if<!std::is_void<In>::value, void>::type
doExec(JobBase *prev, JobBase *jobBase);
template<typename Out, typename ... In>
typename std::enable_if<sizeof...(In) == 0, void>::type
doExec(JobBase *prev, JobBase *jobBase, int * /* disambiguate */ = 0);
}
template<typename Out, typename ... In>
class Job : public JobBase
{
template<typename Out_, typename ... In_>
friend class Job;
template<typename Out_, typename ... In_, typename F_>
friend Job<Out_, In_ ...> start(F_ func);
public:
~Job()
{
// Can't delete in JobBase, since we don't know the type
// and deleting void* is undefined
delete reinterpret_cast<Async::Future<Out>*>(mResult);
}
template<typename Out_, typename ... In_, typename F>
Job<Out_, In_ ...> then(F func)
{
Job<Out_, In_ ...> job(this);
job.mFunc = func;
return job;
}
Async::Future<Out> result() const
{
return *reinterpret_cast<Async::Future<Out>*>(mResult);
}
void exec()
{
Async::Private::doExec<Out, In ...>(mPrev, this);
}
private:
Job(JobBase *parent = nullptr)
: JobBase(parent)
{}
public:
std::function<Async::Future<Out>(In ...)> mFunc;
};
template<typename Out, typename ... In, typename F>
Job<Out, In ...> start(F func)
{
Job<Out, In ...> job;
job.mFunc = std::function<Async::Future<Out>(In ...)>(func);
return job;
}
} // namespace Async
template<typename Out, typename In>
typename std::enable_if<!std::is_void<In>::value, void>::type
Async::Private::doExec(JobBase *prev, JobBase *jobBase)
{
prev->exec();
Async::Future<In> *in = reinterpret_cast<Async::Future<In>*>(prev->mResult);
assert(in->isFinished());
Job<Out, In> *job = dynamic_cast<Job<Out, In>*>(jobBase);
Async::Future<Out> *out = new Async::Future<Out>(job->mFunc(in->value()));
out->waitForFinished();
job->mResult = reinterpret_cast<void*>(out);
};
template<typename Out, typename ... In>
typename std::enable_if<sizeof...(In) == 0, void>::type
Async::Private::doExec(JobBase *prev, JobBase *jobBase, int * /* disambiguation */ = 0)
{
if (prev) {
prev->exec();
Async::Future<void> *in = reinterpret_cast<Async::Future<void>*>(prev->mResult);
assert(in->isFinished());
}
Job<Out> *job = dynamic_cast<Job<Out>*>(jobBase);
Async::Future<Out> *out = new Async::Future<Out>(job->mFunc());
out->waitForFinished();
job->mResult = reinterpret_cast<void*>(out);
};
#endif // ASYNC_H
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