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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* signal.h - Signal & slot implementation
*/
#ifndef __LIBCAMERA_SIGNAL_H__
#define __LIBCAMERA_SIGNAL_H__
#include <functional>
#include <list>
#include <type_traits>
#include <vector>
#include <libcamera/bound_method.h>
#include <libcamera/object.h>
namespace libcamera {
class SignalBase
{
public:
void disconnect(Object *object);
protected:
using SlotList = std::list<BoundMethodBase *>;
void connect(BoundMethodBase *slot);
void disconnect(std::function<bool(SlotList::iterator &)> match);
SlotList slots();
private:
SlotList slots_;
};
template<typename... Args>
class Signal : public SignalBase
{
public:
Signal() {}
~Signal()
{
disconnect();
}
#ifndef __DOXYGEN__
template<typename T, typename R, typename std::enable_if_t<std::is_base_of<Object, T>::value> * = nullptr>
void connect(T *obj, R (T::*func)(Args...),
ConnectionType type = ConnectionTypeAuto)
{
Object *object = static_cast<Object *>(obj);
SignalBase::connect(new BoundMethodMember<T, void, Args...>(obj, object, func, type));
}
template<typename T, typename R, typename std::enable_if_t<!std::is_base_of<Object, T>::value> * = nullptr>
#else
template<typename T, typename R>
#endif
void connect(T *obj, R (T::*func)(Args...))
{
SignalBase::connect(new BoundMethodMember<T, R, Args...>(obj, nullptr, func));
}
template<typename R>
void connect(R (*func)(Args...))
{
SignalBase::connect(new BoundMethodStatic<R, Args...>(func));
}
void disconnect()
{
SignalBase::disconnect([]([[maybe_unused]] SlotList::iterator &iter) {
return true;
});
}
template<typename T>
void disconnect(T *obj)
{
SignalBase::disconnect([obj](SlotList::iterator &iter) {
return (*iter)->match(obj);
});
}
template<typename T, typename R>
void disconnect(T *obj, R (T::*func)(Args...))
{
SignalBase::disconnect([obj, func](SlotList::iterator &iter) {
BoundMethodArgs<R, Args...> *slot =
static_cast<BoundMethodArgs<R, Args...> *>(*iter);
if (!slot->match(obj))
return false;
/*
* If the object matches the slot, the slot is
* guaranteed to be a member slot, so we can safely
* cast it to BoundMethodMember<T, Args...> to match
* func.
*/
return static_cast<BoundMethodMember<T, R, Args...> *>(slot)->match(func);
});
}
template<typename R>
void disconnect(R (*func)(Args...))
{
SignalBase::disconnect([func](SlotList::iterator &iter) {
BoundMethodArgs<R, Args...> *slot =
static_cast<BoundMethodArgs<R, Args...> *>(*iter);
if (!slot->match(nullptr))
return false;
return static_cast<BoundMethodStatic<R, Args...> *>(slot)->match(func);
});
}
void emit(Args... args)
{
/*
* Make a copy of the slots list as the slot could call the
* disconnect operation, invalidating the iterator.
*/
for (BoundMethodBase *slot : slots())
static_cast<BoundMethodArgs<void, Args...> *>(slot)->activate(args...);
}
};
} /* namespace libcamera */
#endif /* __LIBCAMERA_SIGNAL_H__ */
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