Asynco

A C++ library for event-driven asynchronous multi-threaded programming.

Motivation

The original concept was to create an interface capable of asynchronously calling any function. It has since evolved into a library that incorporates a thread pool, each with its own event loop, event-driven programming, and functions inherently designed for asynchronous operation (including periodic and delayed functions).

The asynchronous filesystem is provided solely to guide users on how to wrap any time- or IO-intensive function for asynchronous execution.

Features

• Object oriented
• Small and easy to integrate
• Header only
• Asynchronous programming
• Multithread
• Asynchronous timer functions: periodic, delayed (like setInterval and setTimeout from JS)
• Typed events (on, tick, off) (like EventEmitter from JS: on, emit, etc)
• Event loops
• Multiple parallel execution loops
• Asynchronous file IO
• Based on ASIO (Boost Asio)

Installation

Just download the latest release and unzip it into your project.

#define NUM_OF_RUNNERS 8                // To change the number of threads used by asynco, without this it runs according to the number of cores

#include "asynco/lib/asynco.hpp"        // async_ (), await_()
#include "asynco/lib/triggers.hpp"      // trigger (event emitter)
#include "asynco/lib/timers.hpp"        // periodic, delayed (like setInterval and setTimeout from JS)
#include "asynco/lib/filesystem.hpp"    // for async read and write files

using namespace marcelb;
using namespace asynco;
using namespace triggers;

// At the end of the main function, always set
_asynco_engine.run();
return 0;

Usage

Time asynchronous functions

// start periodic
periodic inter1 ([]() {
     cout << "Interval 1" << endl;
}, 1000);

// stop periodic
inter1.stop();

// how many times it has expired
int t = inter1.ticks();

// is it stopped
bool stoped = inter1.stoped();

// start delayed
delayed time1 ( [] () {
    cout << "Timeout 1 " << endl;
}, 10000);

// stop delayed
time1.stop();

// is it expired
int t = time1.expired();

// is it stopped
bool stoped = time1.stoped();

// If you don't want to save in a variable, but you want to start a timer, use these functions
// And you can also save them, they are only of the shared pointer type

auto d = Delayed( [](){
    cout << "Delayed" << endl;
}, 2000);

auto p = Periodic( [](){
    cout << "Periodic" << endl;
}, 700);

Periodic( [&] (){
    cout << "Delayed expire " << d->expired() << endl;
    cout << "Periodic ticks " << p->ticks() << endl;
    cout << "Delayed stoped " << d->stoped() << endl;
    cout << "Periodic stoped " << p->stoped() << endl;
}, 1000);

Delayed( [&](){
    p->stop();
}, 10000);

Make functions asynchronous

/**
* Run an lambda function asynchronously
*/

async_ ( []() {
    sleep_for(2s);   // only for simulating long duration function
    cout << "nonsync " << endl;
    return 5;
});


/**
 * Run not lambda function
*/

void notLambdaFunction() {
    cout << "Call to not lambda function" << endl;
}

async_ (notLambdaFunction);

/**
 * Run class method
*/

class clm {
    public:
    void classMethode() {
        cout << "Call class method" << endl;
    }
};

clm classes;
async_ ( [&classes] () {
    classes.classMethode();
});



/**
* await_ after runned as async
*/

auto a = async_ ( []() {
    sleep_for(2s);   // only for simulating long duration function
    cout << "nonsync " << endl;
    return 5;
});

cout << await_(a) << endl;

/**
* await_ async function call and use i cout
*/

cout << await_(async_ ( [] () {
    sleep_for(chrono::seconds(1)); // only for simulating long duration function
    cout << "await_ end" << endl;
    return 4;
})) << endl;


/**
 *  Await all
 **/

auto a = async_ ( []() {
    cout << "A" << endl;
    return 3;
});

auto b = async_ ( []() {
    cout << "B" << endl;
    throw runtime_error("Test exception");
    return;
});

auto c = async_ ( []() {
    cout << "C" << endl;
    return "Hello";
});

int a_;
string c_;

auto await_all = [&] () {
    a_ = await_(a);
    await_(b);
    c_ = await_(c);
};

try {
    await_all();
    cout << "a_ " << a_ << " c_ " << c_ << endl;
} catch (const exception& exc) {
    cout << exc.what() << endl;
}

// //  same type 

vector<future<void>> fut_vec;
for (int i=0; i<5; i++) {
    fut_vec.push_back(
        async_ ( [i]() {
            cout << "Async_ " << i << endl;
        })
    );
}

auto await_all = [&] () {
    for (int i=0; i<fut_vec.size(); i++) {
        await_ (fut_vec[i]);
    }
};

/**
* Sleep with delayed sleep implement
*/

void sleep_to (int _time) {
    promise<void> _promise;
    delayed t( [&]() {
        _promise.set_value();
    }, _time);

    return _promise.get_future().get();
}

sleep_to(3000);

/**
* Catch promise reject
*/

void promise_reject (int _time) {
    promise<void> _promise;
    delayed t( [&]() {
        try {
            // simulate except
            throw runtime_error("Error simulation");
            _promise.set_value();
        } catch (...) {
            _promise.set_exception(current_exception());
        }
    }, _time);

    return _promise.get_future().get();
}

try {
    promise_reject(3000);
} catch (runtime_error err) {
    cout<< err.what() << endl;
}

Events

/**
* initialization of typed events
*/

trigger<int, int> ev2int;
trigger<int, string> evintString;
trigger<> evoid;

ev2int.on("sum", [](int a, int b) {
    cout << "Sum " << a+b << endl;
});

evintString.on("substract", [](int a, string b) {
    cout << "Substract " << a-stoi(b) << endl;
});

evoid.on("void", []() {
    cout << "Void emited" << endl;
});

// multiple listeners

string emited2 = "2";

evoid.on("void", [&]() {
    cout << "Void emited " << emited2 << endl;
});

sleep(1);

/**
* Emit
*/

ev2int.tick("sum", 5, 8);

sleep(1);
evintString.tick("substract", 3, to_string(2));

sleep(1);
evoid.tick("void");

// Turn off the event listener

evoid.off("void");
evoid.tick("void"); // nothing is happening

Extend own class whit events

class myOwnClass : public trigger<int> {
    public:
    myOwnClass() : trigger() {};
};

myOwnClass myclass;

delayed t( [&] {
    myclass.tick("constructed", 1);
}, 200);

myclass.on("constructed", [] (int i) {
    cout << "Constructed " << i  << endl;
});

Implementing a class with multiple triggers of different types

class ClassWithTriggers {
    trigger<int> emitter1;
    trigger<string> emitter2;

public:
    template<typename... T>
    void on(const string& key, function<void(T...)> callback) {
        if constexpr (sizeof...(T) == 1 && is_same_v<tuple_element_t<0, tuple<T...>>, int>) {
            emitter1.on(key, callback);
        }
        else if constexpr (sizeof...(T) == 1 && is_same_v<tuple_element_t<0, tuple<T...>>, string>) {
            emitter2.on(key, callback);
        }
    }

    template <typename... Args>
    void tick(const string& key, Args&&... args) {
        if constexpr (sizeof...(Args) == 1 && is_same_v<tuple_element_t<0, tuple<Args...>>, int>) {
            emitter1.tick(key, forward<Args>(args)...);
        }
        else if constexpr (sizeof...(Args) == 1 && is_same_v<tuple_element_t<0, tuple<Args...>>, string>) {
            emitter2.tick(key, forward<Args>(args)...);
        }
        else {
            static_assert(sizeof...(Args) == 0, "Unsupported number or types of arguments");
        }
    }
};

ClassWithTriggers mt;

mt.on<int>("int", function<void(int)>([&](int i) {
    cout << "Emit int " << i << endl;
}));

mt.on<string>("string", function<void(string)>([&](string s) {
    cout << "Emit string " << s << endl;
}));

mt.tick("int", 5);
mt.tick("string", string("Hello world"));

Asynchronous file IO

string data_;

fs::read("test.txt", [&data_] (string data, exception* error) {
    if (error) {
        cout << "Error " << error->what() << endl;
    } else {
        cout << "Data " << endl << data << endl;
        data_ = data;
        cout << "Data_" << data_ << endl;
    }
});

fs::write("test1.txt", "Hello world", [] (exception* error) {
    if (error) {
        cout << "Error " << error->what() << endl;
    } else {
        cout << "Write successfuly" << endl;
    }
});

auto future_data = fs::read("test.txt");

try {
    string data = await_(future_data);
} catch (exception& err) {
    cout << err.what() << endl;
}

auto future_status = fs::write("test.txt", "Hello world");

try {
    await_(future_status);
} catch (exception& err) {
    cout << err.what() << endl;
}

License

APACHE 2.0

Support & Feedback

For support and any feedback, contact the address: marcelb96@yahoo.com.

Contributing

Contributions are always welcome!

Feel free to fork and start working with or without a later pull request. Or contact for suggest and request an option.