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signal.h
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* Signal & slot implementation
*/
#pragma once
#include <functional>
#include <list>
#include <type_traits>
#include <libcamera/base/bound_method.h>
namespace libcamera {
class Object;
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()
{
disconnect();
}
#ifndef __DOXYGEN__
template<typename T, typename R, 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, R, Args...>(obj, object, func, type));
}
template<typename T, typename R, 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));
}
#ifndef __DOXYGEN__
template<typename T, typename Func,
std::enable_if_t<std::is_base_of<Object, T>::value &&
std::is_invocable_v<Func, Args...>> * = nullptr>
void connect(T *obj, Func func, ConnectionType type = ConnectionTypeAuto)
{
Object *object = static_cast<Object *>(obj);
SignalBase::connect(new BoundMethodFunctor<T, void, Func, Args...>(obj, object, func, type));
}
template<typename T, typename Func,
std::enable_if_t<!std::is_base_of<Object, T>::value &&
std::is_invocable_v<Func, Args...>> * = nullptr>
#else
template<typename T, typename Func>
#endif
void connect(T *obj, Func func)
{
SignalBase::connect(new BoundMethodFunctor<T, void, Func, 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 */
bound_method.h
Method bind and invocation.
libcamera::Signal
Generic signal and slot communication mechanism.
Definition signal.h:39
libcamera::Signal::disconnect
void disconnect()
Disconnect the signal from all slots.
Definition signal.h:91
libcamera::Signal::emit
void emit(Args... args)
Emit the signal and call all connected slots.
Definition signal.h:140
libcamera::Signal::connect
void connect(T *obj, R(T::*func)(Args...))
Connect the signal to a member function slot.
Definition signal.h:59
libcamera::Signal::connect
void connect(R(*func)(Args...))
Connect the signal to a static function slot.
Definition signal.h:86
libcamera::Signal::connect
void connect(T *obj, Func func)
Connect the signal to a function object slot.
Definition signal.h:80
libcamera::Signal::disconnect
void disconnect(T *obj)
Disconnect the signal from all slots of the object.
Definition signal.h:99
libcamera::Signal::disconnect
void disconnect(R(*func)(Args...))
Disconnect the signal from the slot static function func.
Definition signal.h:127
libcamera::Signal::disconnect
void disconnect(T *obj, R(T::*func)(Args...))
Disconnect the signal from the object slot member function func.
Definition signal.h:107
libcamera
Top-level libcamera namespace.
Definition bound_method.h:15
libcamera::ConnectionType
ConnectionType
Connection type for asynchronous communication.
Definition bound_method.h:19
libcamera::ConnectionTypeAuto
@ ConnectionTypeAuto
If the sender and the receiver live in the same thread, ConnectionTypeDirect is used....
Definition bound_method.h:20