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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>
#include <libcamera/object.h>
namespace libcamera {
template<typename... Args>
class Signal;
class SlotBase
{
public:
SlotBase(void *obj, bool isObject)
: obj_(obj), isObject_(isObject) {}
virtual ~SlotBase() {}
void *obj() { return obj_; }
bool isObject() const { return isObject_; }
protected:
void *obj_;
bool isObject_;
};
template<typename... Args>
class SlotArgs : public SlotBase
{
public:
SlotArgs(void *obj, bool isObject)
: SlotBase(obj, isObject) {}
virtual void invoke(Args... args) = 0;
protected:
friend class Signal<Args...>;
};
template<typename T, typename... Args>
class SlotMember : public SlotArgs<Args...>
{
public:
SlotMember(T *obj, bool isObject, void (T::*func)(Args...))
: SlotArgs<Args...>(obj, isObject), func_(func) {}
void invoke(Args... args) { (static_cast<T *>(this->obj_)->*func_)(args...); }
private:
friend class Signal<Args...>;
void (T::*func_)(Args...);
};
template<typename... Args>
class SlotStatic : public SlotArgs<Args...>
{
public:
SlotStatic(void (*func)(Args...))
: SlotArgs<Args...>(nullptr, false), func_(func) {}
void invoke(Args... args) { (*func_)(args...); }
private:
friend class Signal<Args...>;
void (*func_)(Args...);
};
class SignalBase
{
public:
template<typename T>
void disconnect(T *object)
{
for (auto iter = slots_.begin(); iter != slots_.end(); ) {
SlotBase *slot = *iter;
if (slot->obj() == object) {
iter = slots_.erase(iter);
delete slot;
} else {
++iter;
}
}
}
protected:
friend class Object;
std::list<SlotBase *> slots_;
};
template<typename... Args>
class Signal : public SignalBase
{
public:
Signal() {}
~Signal()
{
for (SlotBase *slot : slots_) {
if (slot->isObject())
static_cast<Object *>(slot->obj())->disconnect(this);
delete slot;
}
}
#ifndef __DOXYGEN__
template<typename T, typename std::enable_if<std::is_base_of<Object, T>::value>::type * = nullptr>
void connect(T *object, void (T::*func)(Args...))
{
object->connect(this);
slots_.push_back(new SlotMember<T, Args...>(object, true, func));
}
template<typename T, typename std::enable_if<!std::is_base_of<Object, T>::value>::type * = nullptr>
#else
template<typename T>
#endif
void connect(T *object, void (T::*func)(Args...))
{
slots_.push_back(new SlotMember<T, Args...>(object, false, func));
}
void connect(void (*func)(Args...))
{
slots_.push_back(new SlotStatic<Args...>(func));
}
void disconnect()
{
for (SlotBase *slot : slots_)
delete slot;
slots_.clear();
}
template<typename T>
void disconnect(T *object)
{
SignalBase::disconnect(object);
}
template<typename T>
void disconnect(T *object, void (T::*func)(Args...))
{
for (auto iter = slots_.begin(); iter != slots_.end(); ) {
SlotArgs<Args...> *slot = static_cast<SlotArgs<Args...> *>(*iter);
/*
* If the obj() pointer matches the object, the slot is
* guaranteed to be a member slot, so we can safely
* cast it to SlotMember<T, Args...> and access its
* func_ member.
*/
if (slot->obj() == object &&
static_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(); ) {
SlotArgs<Args...> *slot = *iter;
if (slot->obj() == nullptr &&
static_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 *> slots{ slots_.begin(), slots_.end() };
for (SlotBase *slot : slots) {
static_cast<SlotArgs<Args...> *>(slot)->invoke(args...);
}
}
};
} /* namespace libcamera */
#endif /* __LIBCAMERA_SIGNAL_H__ */
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