SignalSlot.cpp

// clang-format off
#include <ImFusion/Core/Signal.h>
using namespace ImFusion;

class MySubject
{
public:
    Signal<> signal1;
    ProtectedSignal<int, std::string> signal2;
};
 
MySubject subject;
 

subject.signal2.connect([](int i, std::string s) {
    std::cout << "Signal2 was emitted with int " << i << " and string " << s << ".";
});
 

// create a connection and store the connection object.
std::shared_ptr<const SignalConnection> connection = subject.signal1.connect([]() { std::cout << "Signal1 was emitted."; });
 
// ...
 
// when needed disconnect the observer
connection->disconnect();
 

// Inherit from SignalReceiver to allow for lifetime-tracking.
class MyObserver : public SignalReceiver
{
public:
    void onEvent() { std::cout << "MyObserver has been notified."; }
}
 
{
    MyObserver observer;
 
    // establish automatic lifetime tracking by passing a reference to the observer instance
    subject.signal1.connect(&observer, [&observer]() { observer.onEvent(); });
    // alternative/simpler overload for member functions:
    subject.signal1.connect(&observer, &MyObserver::onEvent);
}
// Since MyObserver inherits from SignalReceiver and the object instance was provided when
// connecting to the signal, both connections will be disconnected automatically when observer
// is destroyed on scope exit.
 

Signal<> signal;
MyObserver observer1, observer2;
auto connection1 = signal.connect(&observer1, &MyObserver::onEvent);
auto connection2 = signal.connect(&observer2, &MyObserver::onEvent);
 
{
    SignalBlocker blocker(signal);    // temporary blocks all connections of signal
    signal.emitSignal();              // neither observer1 nor observer2 will be notified
}
{
    SignalBlocker blocker(*connection1);    // temporary blocks only connection1
    signal.emitSignal();                    // only observer2 will  be notified
}
{
    SignalBlocker b(signal, observer2);    // temporary blocks all connections between signal and observer2
    signal.emitSignal();                   // only observer1 will  be notified
}
 
// notifies both observer1 and observer2 since signals/connections are no longer blocked
signal.emitSignal();