Luna/kernel/src/fs/devices/DeviceRegistry.cpp

#include "fs/devices/DeviceRegistry.h"
#include "Log.h"
#include "fs/devices/ConsoleDevice.h"
#include "fs/devices/FramebufferDevice.h"
#include "fs/devices/NullDevice.h"
#include "fs/devices/ZeroDevice.h"
#include <luna/Vector.h>

struct DeviceDescriptor
{
    device_create_func_t initializer;
    u32 major;
    u32 minor;
};

Vector<DeviceDescriptor> g_available_devices = {};

namespace DeviceRegistry
{
    Result<SharedPtr<Device>> create_special_device(u32 major, u32 minor)
    {
        for (const auto& descriptor : g_available_devices)
        {
            if (descriptor.major == major && descriptor.minor == minor) return descriptor.initializer();
        }

        return err(ENODEV);
    }

    Result<void> register_special_device(u32 major, u32 minor, device_create_func_t initializer)
    {
        for (const auto& descriptor : g_available_devices)
        {
            if (descriptor.major == major && descriptor.minor == minor) return err(EEXIST);
        }

        kdbgln("DeviceRegistry: registered new device type %u:%u", major, minor);

        return g_available_devices.try_append(
            DeviceDescriptor { .initializer = initializer, .major = major, .minor = minor });
    }

    Result<void> init()
    {
        // Hardcode default devices.
        TRY(register_special_device(DeviceMajorTypes::Memory, 0, NullDevice::create));
        TRY(register_special_device(DeviceMajorTypes::Memory, 1, ZeroDevice::create));
        TRY(register_special_device(DeviceMajorTypes::Console, 0, ConsoleDevice::create));
        TRY(register_special_device(DeviceMajorTypes::Framebuffer, 0, FramebufferDevice::create));

        return {};
    }
}