events.cpp

A simple demonstration of using the event system

#include <libfilezilla/event_handler.hpp>
 
#include <iostream>
#include <string>
#include <vector>
 
// A condition that we'll use in this example to signal the main
// thread that the worker has processed the event.
fz::condition c;
fz::mutex m;
 
 
// Define a new event.
// The event is uniquely identified via the incomplete my_event_type struct and
// has two arguments: A string and a vector of ints.
struct my_event_type;
typedef fz::simple_event<my_event_type, std::string, std::vector<int>> my_event;
 
// A simple event handler
class handler final : public fz::event_handler
{
public:
    handler(fz::event_loop& l)
        : fz::event_handler(l)
    {}
 
    virtual ~handler()
    {
        // This _MUST_ be called to avoid a race so that operator()(fz::event_base const&) is not called on a partially destructed object.
        remove_handler();
    }
 
private:
    // The event loop calls this function for every event sent to this handler.
    virtual void operator()(fz::event_base const& ev)
    {
        // Dispatch the event to the correct function.
        fz::dispatch<my_event>(ev, this, &handler::on_my_event);
    }
 
    void on_my_event(std::string const& s, std::vector<int> const& v)
    {
        std::cout << "Received event with text \"" << s << "\" and a vector with " << v.size() << " elements" << std::endl;
 
        // Signal the condition
        fz::scoped_lock lock(m);
        c.signal(lock);
    }
};
 
int main()
{
    // Start an event loop
    fz::event_loop l;
 
    // Create a handler
    handler h(l);
 
    // Send an event to the handler
    h.send_event<my_event>("Hello World!", std::vector<int>{23, 42, 666});
 
    // Wait until a signal from the worker thread
    fz::scoped_lock lock(m);
    c.wait(lock);
 
    // All done.
    return 0;
}