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strawberry-audio-player-win.../ext/libstrawberry-common/core/closure.h
2019-02-20 21:27:04 +01:00

232 lines
7.4 KiB
C++

/* This file is part of Strawberry.
Copyright 2011, 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 CLOSURE_H
#define CLOSURE_H
#include <functional>
#include <memory>
#include <chrono>
#include <QtGlobal>
#include <QObject>
#include <QFuture>
#include <QFutureWatcher>
#include <QMetaObject>
#include <QMetaMethod>
#include <QSharedPointer>
#include <QByteArray>
#include <QString>
#include <QList>
#include <QTimer>
namespace _detail {
class ObjectHelper;
// Interface for ObjectHelper to call on signal emission.
class ClosureBase {
public:
virtual ~ClosureBase();
virtual void Invoke() = 0;
// Tests only.
ObjectHelper *helper() const;
protected:
explicit ClosureBase(ObjectHelper*);
ObjectHelper *helper_;
private:
Q_DISABLE_COPY(ClosureBase);
};
// QObject helper as templated QObjects do not work.
// Connects to the given signal and invokes the closure when called.
// Deletes itself and the Closure after being invoked.
class ObjectHelper : public QObject {
Q_OBJECT
public:
ObjectHelper(QObject *parent, const char *signal, ClosureBase *closure);
private slots:
void Invoked();
private:
std::unique_ptr<ClosureBase> closure_;
Q_DISABLE_COPY(ObjectHelper);
};
// Helpers for unpacking a variadic template list.
// Base case of no arguments.
void Unpack(QList<QGenericArgument>*);
template <typename Arg>
void Unpack(QList<QGenericArgument> *list, const Arg &arg) {
list->append(Q_ARG(Arg, arg));
}
template <typename Head, typename... Tail>
void Unpack(QList<QGenericArgument> *list, const Head &head, const Tail&... tail) {
Unpack(list, head);
Unpack(list, tail...);
}
template <typename... Args>
class Closure : public ClosureBase {
public:
Closure(
QObject *sender,
const char *signal,
QObject *receiver,
const char *slot,
const Args&... args)
: ClosureBase(new ObjectHelper(sender, signal, this)),
// std::bind is the easiest way to store an argument list.
function_(std::bind(&Closure<Args...>::Call, this, args...)),
receiver_(receiver) {
const QMetaObject *meta_receiver = receiver->metaObject();
QByteArray normalised_slot = QMetaObject::normalizedSignature(slot + 1);
const int index = meta_receiver->indexOfSlot(normalised_slot.constData());
Q_ASSERT(index != -1);
slot_ = meta_receiver->method(index);
QObject::connect(receiver_, SIGNAL(destroyed()), helper_, SLOT(deleteLater()));
}
virtual void Invoke() {
function_();
}
private:
void Call(const Args&... args) {
QList<QGenericArgument> arg_list;
Unpack(&arg_list, args...);
slot_.invoke(
receiver_,
arg_list.size() > 0 ? arg_list[0] : QGenericArgument(),
arg_list.size() > 1 ? arg_list[1] : QGenericArgument(),
arg_list.size() > 2 ? arg_list[2] : QGenericArgument(),
arg_list.size() > 3 ? arg_list[3] : QGenericArgument(),
arg_list.size() > 4 ? arg_list[4] : QGenericArgument(),
arg_list.size() > 5 ? arg_list[5] : QGenericArgument(),
arg_list.size() > 6 ? arg_list[6] : QGenericArgument(),
arg_list.size() > 7 ? arg_list[7] : QGenericArgument(),
arg_list.size() > 8 ? arg_list[8] : QGenericArgument(),
arg_list.size() > 9 ? arg_list[9] : QGenericArgument());
}
std::function<void()> function_;
QObject *receiver_;
QMetaMethod slot_;
};
template <typename T, typename... Args>
class SharedClosure : public Closure<Args...> {
public:
SharedClosure(
QSharedPointer<T> sender,
const char *signal,
QObject *receiver,
const char *slot,
const Args&... args)
: Closure<Args...>(
sender.data(),
signal,
receiver,
slot,
args...),
data_(sender) {
}
private:
QSharedPointer<T> data_;
};
class CallbackClosure : public ClosureBase {
public:
CallbackClosure(QObject *sender, const char *signal, std::function<void()> callback);
virtual void Invoke();
private:
std::function<void()> callback_;
};
} // namespace _detail
template <typename... Args>
_detail::ClosureBase *NewClosure(QObject *sender, const char *signal, QObject *receiver, const char *slot, const Args&... args) {
return new _detail::Closure<Args...>(sender, signal, receiver, slot, args...);
}
// QSharedPointer variant
template <typename T, typename... Args>
_detail::ClosureBase *NewClosure(QSharedPointer<T> sender, const char *signal, QObject *receiver, const char *slot, const Args&... args) {
return new _detail::SharedClosure<T, Args...>(sender, signal, receiver, slot, args...);
}
_detail::ClosureBase *NewClosure(QObject *sender, const char *signal, std::function<void()> callback);
template <typename... Args>
_detail::ClosureBase *NewClosure(QObject *sender, const char *signal, std::function<void(Args...)> callback, const Args&... args) {
return NewClosure(sender, signal, std::bind(callback, args...));
}
template <typename... Args>
_detail::ClosureBase *NewClosure(QObject *sender, const char *signal, void (*callback)(Args...), const Args&... args) {
return NewClosure(sender, signal, std::bind(callback, args...));
}
template <typename T, typename Unused, typename... Args>
_detail::ClosureBase *NewClosure(QObject *sender, const char *signal, T *receiver, Unused (T::*callback)(Args...), const Args&... args) {
return NewClosure(sender, signal, std::bind(callback, receiver, args...));
}
template <typename T, typename... Args>
_detail::ClosureBase *NewClosure(QFuture<T> future, QObject *receiver, const char *slot, const Args&... args) {
QFutureWatcher<T> *watcher = new QFutureWatcher<T>;
watcher->setFuture(future);
QObject::connect(watcher, SIGNAL(finished()), watcher, SLOT(deleteLater()));
return NewClosure(watcher, SIGNAL(finished()), receiver, slot, args...);
}
template <typename T, typename F, typename... Args>
_detail::ClosureBase *NewClosure(QFuture<T> future, const F &callback, const Args&... args) {
QFutureWatcher<T> *watcher = new QFutureWatcher<T>;
watcher->setFuture(future);
QObject::connect(watcher, SIGNAL(finished()), watcher, SLOT(deleteLater()));
return NewClosure(watcher, SIGNAL(finished()), callback, args...);
}
void DoAfter(QObject *receiver, const char *slot, int msec);
void DoAfter(std::function<void()> callback, std::chrono::milliseconds msec);
void DoInAMinuteOrSo(QObject *receiver, const char *slot);
template <typename R, typename P>
void DoAfter(std::function<void()> callback, std::chrono::duration<R, P> duration) {
QTimer *timer = new QTimer;
timer->setSingleShot(true);
NewClosure(timer, SIGNAL(timeout()), callback);
QObject::connect(timer, SIGNAL(timeout()), timer, SLOT(deleteLater()));
std::chrono::milliseconds msec = std::chrono::duration_cast<std::chrono::milliseconds>(duration);
timer->start(msec.count());
}
#endif // CLOSURE_H