ezhangle / eventpp

Minimal C++ Event Bus

Event++ - Minimal C++ message system

Note

This project is no longer maintained.
The event handler and much more has conveyed in EnTT, another project of mine.
Please, refer to the official documentation for more details.

Feel free to keep using Event++ if you want, but do not expect support or new functionalities in future.
Otherwise, try to give a chance to EnTT and you'll see it will not disappoint you.

Synopsis

Minimal C++ message system aimed to work as an event bus for the application.

This class is not meant as a drop-in replacement for the std::function. That is not the purpose of these classes nor the expectation is to get better performance.
This is meant as an event bus, nothing more.

Code Example

Here is an example of use:

using namespace eventpp;

struct EventA: public Event<EventA> { EventA(int) { } };
struct EventB: public Event<EventB> { };
struct EventC: public Event<EventC> { };

void fn(const EventB &) { }

struct MyListener
{
    void receive(const EventA &) { }
    void listen(const EventB &) { }
    void receive(const EventC &) { }
};

using MyBus = Bus<EventA, EventB, EventC>;

// ...

std::shared_ptr<MyListener> listener = std::make_shared<MyListener>();
MyBus bus{};

// ...

// member methods named receive are automatically attached to the bus
bus.reg(listener);

// all the other member methods can be easily attached too
bus.add<EventB, MyListener, &MyListener::listen>(listener);

// also, member methods named receive can be added or removed as it follows
bus.remove<EventA>(listener);
bus.add<EventA>(listener);

// functions are accepted citizens as well
bus.add<EventB, fn>();
bus.remove<EventB, fn>();

// finally, events can be emitted with a single command
bus.publish<EventA>(42);
bus.publish<EventB>();
bus.publish<EventC>();

And that's all.

Motivation

Uhm... Well, I was experimenting. What else?
I needed a minimal event bus for my applications, something easy to use and with a bunch of features like auto disconnection support for the listeners and auto registration of the member methods.

Installation

The eventpp library is a header only library.
Because of that, a user is demanded simply to include it and all the functionalities will be available at once.
Please, note that all the types are part of the eventpp namespace.

Contributors

Michele Caini (skypjack)

License

The MIT License (MIT)

Copyright © 2016 Michele Caini

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.