2024-02-06 17:50:22 +01:00

69 lines
2.7 KiB
C++

#pragma once
#include "Error.h"
#include "Value.h"
#include <filesystem>
#include <future>
#include <utility>
#include <variant>
/// The Plugin class is an abstract interface for any plugin.
///
/// A plugin must itself figure out how to deal with events, load itself,
/// and must react quickly and appropriately to any incoming events or function calls.
/// A plugin may *not* ever block a calling thread unless explicitly marked with
/// "this may block the caller" or similar.
class Plugin {
public:
/// Self-managing pointer type of this plugin.
using Pointer = std::shared_ptr<Plugin>;
/// Allocates a Plugin of the specific derived plugin type.
template <typename T, typename... Args>
static Pointer make_pointer(Args&&... args) {
return std::shared_ptr<Plugin>(new T(std::forward<Args>(args)...));
}
/// Default constructor to enable derived classes to default-construct.
Plugin() = default;
/// Plugin is not copyable.
Plugin(const Plugin&) = delete;
/// Plugin is not copyable.
Plugin& operator=(const Plugin&) = delete;
/// Plugin is movable.
Plugin(Plugin&&) = default;
/// Plugin is movable.
Plugin& operator=(Plugin&&) = default;
/// Default destructor but virtual, to make the compiler happy.
virtual ~Plugin() = default;
/// Called when the plugin should initialize its state.
/// This may block the caller.
virtual Error initialize() = 0;
/// Called when the plugin should tear down and clean up its state.
/// This may block the caller.
virtual Error cleanup() = 0;
/// Called when the plugin should be reloaded. Usually it's a good idea
/// to notify the plugin's code, call cleanup(), etc. internally.
virtual Error reload() = 0;
/// Returns the name of the plugin.
virtual std::string name() const = 0;
/// Returns the path to the plugin - this can either be the folder in which
/// the plugin's files live, or the plugin itself if it's a single file.
/// The exact format of what this returns (directory/file) is implementation defined.
virtual std::filesystem::path path() const = 0;
/// Instructs the plugin to handle the given event, with the given arguments.
/// Returns a future with a result if this event will be handled by the plugin, otherwise must return
/// std::nullopt.
virtual std::shared_future<std::vector<Value>> handle_event(const std::string& event_name, const std::shared_ptr<Value>& args) = 0;
/// Returns how much memory this state thinks it uses.
///
/// This value is difficult to calculate for some use-cases, but a rough ballpark
/// should be returned regardless.
virtual size_t memory_usage() const = 0;
};