strawberry-audio-player-win.../ext/libstrawberry-common/core/concurrentrun.h

138 lines
4.1 KiB
C++

/* This file is part of Strawberry.
Copyright 2012, David Sansome <me@davidsansome.com>
Strawberry 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 3 of the License, or
(at your option) any later version.
Strawberry 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 Strawberry. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef CONCURRENTRUN_H
#define CONCURRENTRUN_H
#include <functional>
#include <QFuture>
#include <QRunnable>
#include <QThreadPool>
/*
The aim of ThreadFunctor classes and ConcurrentRun::Run() functions is to
complete QtConcurrentRun, which lack support for using a particular
QThreadPool, as it always uses QThreadPool::globalInstance().
This is problematic when we do not want to share the same thread pool over
all the application, but want to keep the convenient QtConcurrent::run()
functor syntax.
With ConcurrentRun::Run(), time critical changes can be performed in their
own pool, which is not empty by other actions (as it happens when using
QtConcurrentRun::run()).
ThreadFunctor classes are used to store a functor and its arguments, and
Run() functions are used for convenience: to directly create a new
ThreadFunctor object and start it.
*/
/*
Base abstract classes ThreadFunctorBase and ThreadFunctor (for void and
non-void result):
*/
template<typename ReturnType>
class ThreadFunctorBase : public QFutureInterface<ReturnType>, public QRunnable {
public:
ThreadFunctorBase() {}
QFuture<ReturnType> Start(QThreadPool* thread_pool) {
this->setRunnable(this);
this->reportStarted();
Q_ASSERT(thread_pool);
QFuture<ReturnType> future = this->future();
thread_pool->start(this, 0 /* priority: currently we do not support
changing the priority. Might be added later
if needed */);
return future;
}
virtual void run() = 0;
};
template <typename ReturnType, typename... Args>
class ThreadFunctor : public ThreadFunctorBase<ReturnType> {
public:
ThreadFunctor(std::function<ReturnType (Args...)> function,
Args... args)
: function_(std::bind(function, args...)) {
}
virtual void run() {
this->reportResult(function_());
this->reportFinished();
}
private:
std::function<ReturnType()> function_;
};
// Partial specialisation for void return type.
template <typename... Args>
class ThreadFunctor <void, Args...> : public ThreadFunctorBase<void> {
public:
ThreadFunctor(std::function<void (Args...)> function,
Args... args)
: function_(std::bind(function, args...)) {
}
virtual void run() {
function_();
this->reportFinished();
}
private:
std::function<void()> function_;
};
/*
Run functions
*/
namespace ConcurrentRun {
// Empty argument form.
template <typename ReturnType>
QFuture<ReturnType> Run(
QThreadPool* threadpool,
std::function<ReturnType ()> function) {
return (new ThreadFunctor<ReturnType>(function))->Start(threadpool);
}
// Function object with arguments form.
template <typename ReturnType, typename... Args>
QFuture<ReturnType> Run(
QThreadPool* threadpool,
std::function<ReturnType (Args...)> function,
const Args&... args) {
return (new ThreadFunctor<ReturnType, Args...>(
function, args...))->Start(threadpool);
}
// Support passing C function pointers instead of function objects.
template <typename ReturnType, typename... Args>
QFuture<ReturnType> Run(
QThreadPool* threadpool,
ReturnType (*function) (Args...),
const Args&... args) {
return Run(
threadpool, std::function<ReturnType (Args...)>(function), args...);
}
}
#endif // CONCURRENTRUN_H