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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 <list>
#include <vector>
namespace libcamera {
template<typename... Args>
class Signal;
template<typename... Args>
class SlotBase
{
public:
SlotBase(void *obj)
: obj_(obj) { }
virtual ~SlotBase() { }
virtual void invoke(Args... args) = 0;
protected:
friend class Signal<Args...>;
void *obj_;
};
template<typename T, typename... Args>
class SlotMember : public SlotBase<Args...>
{
public:
SlotMember(T *obj, void(T::*func)(Args...))
: SlotBase<Args...>(obj), func_(func) { }
void invoke(Args... args) { (reinterpret_cast<T *>(this->obj_)->*func_)(args...); }
private:
friend class Signal<Args...>;
void(T::*func_)(Args...);
};
template<typename... Args>
class SlotStatic : public SlotBase<Args...>
{
public:
SlotStatic(void(*func)(Args...))
: SlotBase<Args...>(nullptr), func_(func) { }
void invoke(Args... args) { (*func_)(args...); }
private:
friend class Signal<Args...>;
void(*func_)(Args...);
};
template<typename... Args>
class Signal
{
public:
Signal() { }
~Signal()
{
for (SlotBase<Args...> *slot : slots_)
delete slot;
}
template<typename T>
void connect(T *object, void(T::*func)(Args...))
{
slots_.push_back(new SlotMember<T, Args...>(object, func));
}
void connect(void(*func)(Args...))
{
slots_.push_back(new SlotStatic<Args...>(func));
}
void disconnect()
{
for (SlotBase<Args...> *slot : slots_)
delete slot;
slots_.clear();
}
template<typename T>
void disconnect(T *object)
{
for (auto iter = slots_.begin(); iter != slots_.end(); ) {
SlotBase<Args...> *slot = *iter;
if (slot->obj_ == object) {
iter = slots_.erase(iter);
delete slot;
} else {
++iter;
}
}
}
template<typename T>
void disconnect(T *object, void(T::*func)(Args...))
{
for (auto iter = slots_.begin(); iter != slots_.end(); ) {
SlotBase<Args...> *slot = *iter;
/*
* If the obj_ pointer matches the object types must
* match, so we can safely cast to SlotMember<T, Args>.
*/
if (slot->obj_ == object &&
reinterpret_cast<SlotMember<T, Args...> *>(slot)->func_ == func) {
iter = slots_.erase(iter);
delete slot;
} else {
++iter;
}
}
}
void disconnect(void(*func)(Args...))
{
for (auto iter = slots_.begin(); iter != slots_.end(); ) {
SlotBase<Args...> *slot = *iter;
if (slot->obj_ == nullptr &&
reinterpret_cast<SlotStatic<Args...> *>(slot)->func_ == func) {
iter = slots_.erase(iter);
delete slot;
} else {
++iter;
}
}
}
void emit(Args... args)
{
/*
* Make a copy of the slots list as the slot could call the
* disconnect operation, invalidating the iterator.
*/
std::vector<SlotBase<Args...> *> slots{ slots_.begin(), slots_.end() };
for (SlotBase<Args...> *slot : slots)
slot->invoke(args...);
}
private:
std::list<SlotBase<Args...> *> slots_;
};
} /* namespace libcamera */
#endif /* __LIBCAMERA_SIGNAL_H__ */
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