renderbug-cpp/lib/Figments/Figment.h

#pragma once
#include <Arduino.h>
#include <functional>
#include <ArduinoLog.h>

#define F_LIKELY(x) __builtin_expect(!!(x), true)
#define F_UNLIKELY(x) __builtin_expect(!!(x), false)

class Display;
class InputEvent;
class InputSource;

/**
 * A generic interface for anything that can be executed and respond to events.
 */
struct Loopable {

    /**
     * Called by the MainLoop to process events
     */
    virtual void handleEvent(const InputEvent& event) {}

    /**
     * Called on every MainLoop tick
     */
    virtual void loop() = 0;
};

/**
 * A Loopable that can be named and may be started or stopped in a MainLoop.
 */
struct Task : public virtual Loopable {
    /**
     * Implement in a subclass to run when the task is started
     * The default implementation does nothing.
     */
    virtual void onStart() {};

    /**
     * Implement in a subclass to run when the task is stopped.
     * The default implementation does nothing.
     */
    virtual void onStop() {};

    enum State {
        Running,
        Stopped,
    };

    Task() {}
    explicit Task(const char* name) : name(name) {}

    /**
     * Starts the task and makes it schedulable
     */
    void start() { state = Running; onStart(); }

    /**
     * Stops the task and makes it unschedulable
     */
    void stop() { onStop(); state = Stopped; }

    /**
     * A hacky way to determine if a task is a Figment subclass or not, without
     * having to resort to RTTI
     */
    virtual bool isFigment() const { return false; }

    const char* name = "";
    State state = Stopped;
};

/**
 * Functional lambda interface for creating Tasks
 */
struct TaskFunc: public Task {
    TaskFunc(std::function<void()> func) : Task("lambda"), func(func) {}
    void loop() override {func();}
    std::function<void()> func;
};

/**
 * A Task with a graphical output
 */
struct Figment: public Task {
    Figment() : Task() {}
    explicit Figment(const char* name) : Task(name) {}

    /**
     * Called when the Figment should render its output to a display
     */
    virtual void render(Display* dpy) const = 0;
    bool isFigment() const override { return true; }
};

/**
 * Functional lambda interface for creating Figments
 */
struct FigmentFunc: public Figment {
    FigmentFunc(std::function<void(Display*)> func) : Figment("lambda"), func(func) {}
    void loop() override {}
    void render(Display* dpy) const override {
        func(dpy);
    }
    std::function<void(Display*)> func;
};