future considerations

menu.cpp

// UPDATE: So, I've implemented a packaged_future template which makes it possible to use just a single variable:
// https://gist.github.com/geneotech/c9e8177b34dbace6b1fa23129977c9d1

// Original problem:

// UPDATE: Okay, so apparently, std::shared_future can get multiple times...
// But should I use std::shared_future even though just one thread queries it for value?

// Consider a main menu class which, on construction, 
// is supposed to query a website for a news headline in order 
// to render it later on top of the game's main menu.
// (which I already had before, just uglier).
// This sounds like a task for std::future, but I think using two member variables for this is ugly, 
// and I don't see a way to use just a single variable

// Or maybe it is in fact good to use two variables?
// Or maybe we should make a packaged_future template helper which stores both and returns an std::optional?

// Helper template (recommended by SO folks)
template <class T>
bool is_ready(const std::future<T>& f) {
    return f.wait_for(std::chrono::seconds(0)) == std::future_status::ready;
}

class main_menu_setup {
    std::future<void> latest_news_future;
    std::wstring latest_news; 

    main_menu_setup(const main_menu_settings settings) {
        query_latest_news(settings.latest_news_url);
        // more ...
    }

    void query_latest_news(const std::string& url) {
        latest_news_future = std::async(std::launc::async, [&]() {
            auto html = augs::http_get_request(url);

            // processing...
            
            latest_news = to_wstring(html);
        });
    }

    // these are meant to be called repeatedly later
    
    void draw() const {
        if (latest_news_future.valid() && is_ready(latest_news_future)) {
            print(latest_news);
        };
    }
}

// Do you think there's a better way?