src/joystick/hidapi/SDL_hidapijoystick.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2019 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"

#ifdef SDL_JOYSTICK_HIDAPI

#include "SDL_endian.h"
#include "SDL_hints.h"
#include "SDL_log.h"
#include "SDL_mutex.h"
#include "SDL_thread.h"
#include "SDL_timer.h"
#include "SDL_joystick.h"
#include "../SDL_sysjoystick.h"
#include "SDL_hidapijoystick_c.h"
#include "../../SDL_hints_c.h"

#if defined(__WIN32__)
#include "../../core/windows/SDL_windows.h"
#endif

#if defined(__MACOSX__)
#include <CoreFoundation/CoreFoundation.h>
#include <mach/mach.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/usb/USBSpec.h>
#endif

#if defined(__LINUX__)
#include "../../core/linux/SDL_udev.h"
#ifdef SDL_USE_LIBUDEV
#include <poll.h>
#endif
#endif

struct joystick_hwdata
{
    SDL_HIDAPI_DeviceDriver *driver;
    void *context;

    SDL_mutex *mutex;
    hid_device *dev;
};

typedef struct _SDL_HIDAPI_Device
{
    SDL_JoystickID instance_id;
    char *name;
    char *path;
    Uint16 vendor_id;
    Uint16 product_id;
    Uint16 version;
    SDL_JoystickGUID guid;
    int interface_number;   /* Available on Windows and Linux */
    Uint16 usage_page;      /* Available on Windows and Mac OS X */
    Uint16 usage;           /* Available on Windows and Mac OS X */
    SDL_HIDAPI_DeviceDriver *driver;

    /* Used during scanning for device changes */
    SDL_bool seen;

    struct _SDL_HIDAPI_Device *next;
} SDL_HIDAPI_Device;

static SDL_HIDAPI_DeviceDriver *SDL_HIDAPI_drivers[] = {
#ifdef SDL_JOYSTICK_HIDAPI_PS4
    &SDL_HIDAPI_DriverPS4,
#endif
#ifdef SDL_JOYSTICK_HIDAPI_STEAM
    &SDL_HIDAPI_DriverSteam,
#endif
#ifdef SDL_JOYSTICK_HIDAPI_SWITCH
    &SDL_HIDAPI_DriverSwitch,
#endif
#ifdef SDL_JOYSTICK_HIDAPI_XBOX360
    &SDL_HIDAPI_DriverXbox360,
#endif
#ifdef SDL_JOYSTICK_HIDAPI_XBOXONE
    &SDL_HIDAPI_DriverXboxOne,
#endif
};
static int SDL_HIDAPI_numdrivers = 0;
static SDL_HIDAPI_Device *SDL_HIDAPI_devices;
static int SDL_HIDAPI_numjoysticks = 0;
static SDL_bool initialized = SDL_FALSE;

#if defined(SDL_USE_LIBUDEV)
static const SDL_UDEV_Symbols * usyms = NULL;
#endif

static struct
{
    SDL_bool m_bHaveDevicesChanged;
    SDL_bool m_bCanGetNotifications;
    Uint32 m_unLastDetect;

#if defined(__WIN32__)
    SDL_threadID m_nThreadID;
    WNDCLASSEXA m_wndClass;
    HWND m_hwndMsg;
    HDEVNOTIFY m_hNotify;
    double m_flLastWin32MessageCheck;
#endif

#if defined(__MACOSX__)
    IONotificationPortRef m_notificationPort;
    mach_port_t m_notificationMach;
#endif

#if defined(SDL_USE_LIBUDEV)
    struct udev *m_pUdev;
    struct udev_monitor *m_pUdevMonitor;
    int m_nUdevFd;
#endif
} SDL_HIDAPI_discovery;


#ifdef __WIN32__
struct _DEV_BROADCAST_HDR
{
    DWORD       dbch_size;
    DWORD       dbch_devicetype;
    DWORD       dbch_reserved;
};

typedef struct _DEV_BROADCAST_DEVICEINTERFACE_A
{
    DWORD       dbcc_size;
    DWORD       dbcc_devicetype;
    DWORD       dbcc_reserved;
    GUID        dbcc_classguid;
    char        dbcc_name[ 1 ];
} DEV_BROADCAST_DEVICEINTERFACE_A, *PDEV_BROADCAST_DEVICEINTERFACE_A;

typedef struct  _DEV_BROADCAST_HDR      DEV_BROADCAST_HDR;
#define DBT_DEVICEARRIVAL               0x8000  /* system detected a new device */
#define DBT_DEVICEREMOVECOMPLETE        0x8004  /* device was removed from the system */
#define DBT_DEVTYP_DEVICEINTERFACE      0x00000005  /* device interface class */
#define DBT_DEVNODES_CHANGED            0x0007
#define DBT_CONFIGCHANGED               0x0018
#define DBT_DEVICETYPESPECIFIC          0x8005  /* type specific event */
#define DBT_DEVINSTSTARTED              0x8008  /* device installed and started */

#include <initguid.h>
DEFINE_GUID(GUID_DEVINTERFACE_USB_DEVICE, 0xA5DCBF10L, 0x6530, 0x11D2, 0x90, 0x1F, 0x00, 0xC0, 0x4F, 0xB9, 0x51, 0xED);

static LRESULT CALLBACK ControllerWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message) {
    case WM_DEVICECHANGE:
        switch (wParam) {
        case DBT_DEVICEARRIVAL:
        case DBT_DEVICEREMOVECOMPLETE:
            if (((DEV_BROADCAST_HDR*)lParam)->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
                SDL_HIDAPI_discovery.m_bHaveDevicesChanged = SDL_TRUE;
            }
            break;
        }
        return TRUE;
    }

    return DefWindowProc(hwnd, message, wParam, lParam);
}
#endif /* __WIN32__ */


#if defined(__MACOSX__)
static void CallbackIOServiceFunc(void *context, io_iterator_t portIterator)
{
    /* Must drain the iterator, or we won't receive new notifications */
    io_object_t entry;
    while ((entry = IOIteratorNext(portIterator)) != 0) {
        IOObjectRelease(entry);
        *(SDL_bool*)context = SDL_TRUE;
    }
}
#endif /* __MACOSX__ */

static void
HIDAPI_InitializeDiscovery()
{
    SDL_HIDAPI_discovery.m_bHaveDevicesChanged = SDL_TRUE;
    SDL_HIDAPI_discovery.m_bCanGetNotifications = SDL_FALSE;
    SDL_HIDAPI_discovery.m_unLastDetect = 0;

#if defined(__WIN32__)
    SDL_HIDAPI_discovery.m_nThreadID = SDL_ThreadID();

    SDL_memset(&SDL_HIDAPI_discovery.m_wndClass, 0x0, sizeof(SDL_HIDAPI_discovery.m_wndClass));
    SDL_HIDAPI_discovery.m_wndClass.hInstance = GetModuleHandle(NULL);
    SDL_HIDAPI_discovery.m_wndClass.lpszClassName = "SDL_HIDAPI_DEVICE_DETECTION";
    SDL_HIDAPI_discovery.m_wndClass.lpfnWndProc = ControllerWndProc;      /* This function is called by windows */
    SDL_HIDAPI_discovery.m_wndClass.cbSize = sizeof(WNDCLASSEX);

    RegisterClassExA(&SDL_HIDAPI_discovery.m_wndClass);
    SDL_HIDAPI_discovery.m_hwndMsg = CreateWindowExA(0, "SDL_HIDAPI_DEVICE_DETECTION", NULL, 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);

    {
        DEV_BROADCAST_DEVICEINTERFACE_A devBroadcast;
        SDL_memset( &devBroadcast, 0x0, sizeof( devBroadcast ) );

        devBroadcast.dbcc_size = sizeof( devBroadcast );
        devBroadcast.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
        devBroadcast.dbcc_classguid = GUID_DEVINTERFACE_USB_DEVICE;

        /* DEVICE_NOTIFY_ALL_INTERFACE_CLASSES is important, makes GUID_DEVINTERFACE_USB_DEVICE ignored,
         * but that seems to be necessary to get a notice after each individual usb input device actually
         * installs, rather than just as the composite device is seen.
         */
        SDL_HIDAPI_discovery.m_hNotify = RegisterDeviceNotification( SDL_HIDAPI_discovery.m_hwndMsg, &devBroadcast, DEVICE_NOTIFY_WINDOW_HANDLE | DEVICE_NOTIFY_ALL_INTERFACE_CLASSES );
        SDL_HIDAPI_discovery.m_bCanGetNotifications = ( SDL_HIDAPI_discovery.m_hNotify != 0 );
    }
#endif /* __WIN32__ */

#if defined(__MACOSX__)
    SDL_HIDAPI_discovery.m_notificationPort = IONotificationPortCreate(kIOMasterPortDefault);
    if (SDL_HIDAPI_discovery.m_notificationPort) {
        {
            CFMutableDictionaryRef matchingDict = IOServiceMatching("IOUSBDevice");

            /* Note: IOServiceAddMatchingNotification consumes the reference to matchingDict */
            io_iterator_t portIterator = 0;
            io_object_t entry;
            if (IOServiceAddMatchingNotification(SDL_HIDAPI_discovery.m_notificationPort, kIOMatchedNotification, matchingDict, CallbackIOServiceFunc, &SDL_HIDAPI_discovery.m_bHaveDevicesChanged, &portIterator) == 0) {
                /* Must drain the existing iterator, or we won't receive new notifications */
                while ((entry = IOIteratorNext(portIterator)) != 0) {
                    IOObjectRelease(entry);
                }
            } else {
                IONotificationPortDestroy(SDL_HIDAPI_discovery.m_notificationPort);
                SDL_HIDAPI_discovery.m_notificationPort = nil;
            }
        }
        {
            CFMutableDictionaryRef matchingDict = IOServiceMatching("IOBluetoothDevice");

            /* Note: IOServiceAddMatchingNotification consumes the reference to matchingDict */
            io_iterator_t portIterator = 0;
            io_object_t entry;
            if (IOServiceAddMatchingNotification(SDL_HIDAPI_discovery.m_notificationPort, kIOMatchedNotification, matchingDict, CallbackIOServiceFunc, &SDL_HIDAPI_discovery.m_bHaveDevicesChanged, &portIterator) == 0) {
                /* Must drain the existing iterator, or we won't receive new notifications */
                while ((entry = IOIteratorNext(portIterator)) != 0) {
                    IOObjectRelease(entry);
                }
            } else {
                IONotificationPortDestroy(SDL_HIDAPI_discovery.m_notificationPort);
                SDL_HIDAPI_discovery.m_notificationPort = nil;
            }
        }
    }

    SDL_HIDAPI_discovery.m_notificationMach = MACH_PORT_NULL;
    if (SDL_HIDAPI_discovery.m_notificationPort) {
        SDL_HIDAPI_discovery.m_notificationMach = IONotificationPortGetMachPort(SDL_HIDAPI_discovery.m_notificationPort);
    }

    SDL_HIDAPI_discovery.m_bCanGetNotifications = (SDL_HIDAPI_discovery.m_notificationMach != MACH_PORT_NULL);

#endif // __MACOSX__

#if defined(SDL_USE_LIBUDEV)
    SDL_HIDAPI_discovery.m_pUdev = NULL;
    SDL_HIDAPI_discovery.m_pUdevMonitor = NULL;
    SDL_HIDAPI_discovery.m_nUdevFd = -1;

    usyms = SDL_UDEV_GetUdevSyms();
    if (usyms) {
        SDL_HIDAPI_discovery.m_pUdev = usyms->udev_new();
    }
    if (SDL_HIDAPI_discovery.m_pUdev) {
        SDL_HIDAPI_discovery.m_pUdevMonitor = usyms->udev_monitor_new_from_netlink(SDL_HIDAPI_discovery.m_pUdev, "udev");
        if (SDL_HIDAPI_discovery.m_pUdevMonitor) {
            usyms->udev_monitor_enable_receiving(SDL_HIDAPI_discovery.m_pUdevMonitor);
            SDL_HIDAPI_discovery.m_nUdevFd = usyms->udev_monitor_get_fd(SDL_HIDAPI_discovery.m_pUdevMonitor);
            SDL_HIDAPI_discovery.m_bCanGetNotifications = SDL_TRUE;
        }
    }

#endif /* SDL_USE_LIBUDEV */
}

static void
HIDAPI_UpdateDiscovery()
{
    if (!SDL_HIDAPI_discovery.m_bCanGetNotifications) {
        const Uint32 SDL_HIDAPI_DETECT_INTERVAL_MS = 3000;  /* Update every 3 seconds */
        Uint32 now = SDL_GetTicks();
        if (!SDL_HIDAPI_discovery.m_unLastDetect || SDL_TICKS_PASSED(now, SDL_HIDAPI_discovery.m_unLastDetect + SDL_HIDAPI_DETECT_INTERVAL_MS)) {
            SDL_HIDAPI_discovery.m_bHaveDevicesChanged = SDL_TRUE;
            SDL_HIDAPI_discovery.m_unLastDetect = now;
        }
        return;
    }

#if defined(__WIN32__)
#if 0 /* just let the usual SDL_PumpEvents loop dispatch these, fixing bug 4286. --ryan. */
    /* We'll only get messages on the same thread that created the window */
    if (SDL_ThreadID() == SDL_HIDAPI_discovery.m_nThreadID) {
        MSG msg;
        while (PeekMessage(&msg, SDL_HIDAPI_discovery.m_hwndMsg, 0, 0, PM_NOREMOVE)) {
            if (GetMessageA(&msg, SDL_HIDAPI_discovery.m_hwndMsg, 0, 0) != 0) {
                TranslateMessage(&msg);
                DispatchMessage(&msg);
            }
        }
    }
#endif
#endif /* __WIN32__ */

#if defined(__MACOSX__)
    if (SDL_HIDAPI_discovery.m_notificationPort) {
        struct { mach_msg_header_t hdr; char payload[ 4096 ]; } msg;
        while (mach_msg(&msg.hdr, MACH_RCV_MSG | MACH_RCV_TIMEOUT, 0, sizeof(msg), SDL_HIDAPI_discovery.m_notificationMach, 0, MACH_PORT_NULL) == KERN_SUCCESS) {
            IODispatchCalloutFromMessage(NULL, &msg.hdr, SDL_HIDAPI_discovery.m_notificationPort);
        }
    }
#endif

#if defined(SDL_USE_LIBUDEV)
    if (SDL_HIDAPI_discovery.m_nUdevFd >= 0) {
        /* Drain all notification events.
         * We don't expect a lot of device notifications so just
         * do a new discovery on any kind or number of notifications.
         * This could be made more restrictive if necessary.
         */
        for (;;) {
            struct pollfd PollUdev;
            struct udev_device *pUdevDevice;

            PollUdev.fd = SDL_HIDAPI_discovery.m_nUdevFd;
            PollUdev.events = POLLIN;
            if (poll(&PollUdev, 1, 0) != 1) {
                break;
            }

            SDL_HIDAPI_discovery.m_bHaveDevicesChanged = SDL_TRUE;

            pUdevDevice = usyms->udev_monitor_receive_device(SDL_HIDAPI_discovery.m_pUdevMonitor);
            if (pUdevDevice) {
                usyms->udev_device_unref(pUdevDevice);
            }
        }
    }
#endif
}

static void
HIDAPI_ShutdownDiscovery()
{
#if defined(__WIN32__)
    if (SDL_HIDAPI_discovery.m_hNotify)
        UnregisterDeviceNotification(SDL_HIDAPI_discovery.m_hNotify);

    if (SDL_HIDAPI_discovery.m_hwndMsg) {
        DestroyWindow(SDL_HIDAPI_discovery.m_hwndMsg);
    }

    UnregisterClassA(SDL_HIDAPI_discovery.m_wndClass.lpszClassName, SDL_HIDAPI_discovery.m_wndClass.hInstance);
#endif

#if defined(__MACOSX__)
    if (SDL_HIDAPI_discovery.m_notificationPort) {
        IONotificationPortDestroy(SDL_HIDAPI_discovery.m_notificationPort);
    }
#endif

#if defined(SDL_USE_LIBUDEV)
    if (usyms) {
        if (SDL_HIDAPI_discovery.m_pUdevMonitor) {
            usyms->udev_monitor_unref(SDL_HIDAPI_discovery.m_pUdevMonitor);
        }
        if (SDL_HIDAPI_discovery.m_pUdev) {
            usyms->udev_unref(SDL_HIDAPI_discovery.m_pUdev);
        }
        SDL_UDEV_ReleaseUdevSyms();
        usyms = NULL;
    }
#endif
}

static SDL_bool
HIDAPI_IsDeviceSupported(Uint16 vendor_id, Uint16 product_id, Uint16 version, const char *name)
{
    int i;

    for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
        SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
        if (driver->enabled && driver->IsSupportedDevice(vendor_id, product_id, version, -1, name)) {
            return SDL_TRUE;
        }
    }
    return SDL_FALSE;
}

static SDL_HIDAPI_DeviceDriver *
HIDAPI_GetDeviceDriver(SDL_HIDAPI_Device *device)
{
    const Uint16 USAGE_PAGE_GENERIC_DESKTOP = 0x0001;
    const Uint16 USAGE_JOYSTICK = 0x0004;
    const Uint16 USAGE_GAMEPAD = 0x0005;
    const Uint16 USAGE_MULTIAXISCONTROLLER = 0x0008;
    int i;

    if (SDL_ShouldIgnoreJoystick(device->name, device->guid)) {
        return NULL;
    }

    if (device->usage_page && device->usage_page != USAGE_PAGE_GENERIC_DESKTOP) {
        return NULL;
    }
    if (device->usage && device->usage != USAGE_JOYSTICK && device->usage != USAGE_GAMEPAD && device->usage != USAGE_MULTIAXISCONTROLLER) {
        return NULL;
    }

    for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
        SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
        if (driver->enabled && driver->IsSupportedDevice(device->vendor_id, device->product_id, device->version, device->interface_number, device->name)) {
            return driver;
        }
    }
    return NULL;
}

static SDL_HIDAPI_Device *
HIDAPI_GetJoystickByIndex(int device_index)
{
    SDL_HIDAPI_Device *device = SDL_HIDAPI_devices;
    while (device) {
        if (device->driver) {
            if (device_index == 0) {
                break;
            }
            --device_index;
        }
        device = device->next;
    }
    return device;
}

static SDL_HIDAPI_Device *
HIDAPI_GetJoystickByInfo(const char *path, Uint16 vendor_id, Uint16 product_id)
{
    SDL_HIDAPI_Device *device = SDL_HIDAPI_devices;
    while (device) {
        if (device->vendor_id == vendor_id && device->product_id == product_id &&
            SDL_strcmp(device->path, path) == 0) {
            break;
        }
        device = device->next;
    }
    return device;
}

static void SDLCALL
SDL_HIDAPIDriverHintChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
{
    int i;
    SDL_HIDAPI_Device *device = SDL_HIDAPI_devices;
    SDL_bool enabled = SDL_GetStringBoolean(hint, SDL_TRUE);

    if (SDL_strcmp(name, SDL_HINT_JOYSTICK_HIDAPI) == 0) {
        for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
            SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
            driver->enabled = SDL_GetHintBoolean(driver->hint, enabled);
        }
    } else {
        for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
            SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
            if (SDL_strcmp(name, driver->hint) == 0) {
                driver->enabled = enabled;
                break;
            }
        }
    }

    SDL_HIDAPI_numdrivers = 0;
    for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
        SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
        if (driver->enabled) {
            ++SDL_HIDAPI_numdrivers;
        }
    }

    /* Update device list if driver availability changes */
    while (device) {
        if (device->driver) {
            if (!device->driver->enabled) {
                device->driver = NULL;

                --SDL_HIDAPI_numjoysticks;

                SDL_PrivateJoystickRemoved(device->instance_id);
            }
        } else {
            device->driver = HIDAPI_GetDeviceDriver(device);
            if (device->driver) {
                device->instance_id = SDL_GetNextJoystickInstanceID();

                ++SDL_HIDAPI_numjoysticks;

                SDL_PrivateJoystickAdded(device->instance_id);
            }
        }
        device = device->next;
    }
}

static void HIDAPI_JoystickDetect(void);

static int
HIDAPI_JoystickInit(void)
{
    int i;

    if (initialized) {
        return 0;
    }

    if (hid_init() < 0) {
        SDL_SetError("Couldn't initialize hidapi");
        return -1;
    }

    for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
        SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
        SDL_AddHintCallback(driver->hint, SDL_HIDAPIDriverHintChanged, NULL);
    }
    SDL_AddHintCallback(SDL_HINT_JOYSTICK_HIDAPI,
                        SDL_HIDAPIDriverHintChanged, NULL);
    HIDAPI_InitializeDiscovery();
    HIDAPI_JoystickDetect();

    initialized = SDL_TRUE;

    return 0;
}

static int
HIDAPI_JoystickGetCount(void)
{
    return SDL_HIDAPI_numjoysticks;
}

static void
HIDAPI_AddDevice(struct hid_device_info *info)
{
    SDL_HIDAPI_Device *device;
    SDL_HIDAPI_Device *curr, *last = NULL;

    for (curr = SDL_HIDAPI_devices, last = NULL; curr; last = curr, curr = curr->next) {
        continue;
    }

    device = (SDL_HIDAPI_Device *)SDL_calloc(1, sizeof(*device));
    if (!device) {
        return;
    }
    device->instance_id = -1;
    device->seen = SDL_TRUE;
    device->vendor_id = info->vendor_id;
    device->product_id = info->product_id;
    device->version = info->release_number;
    device->interface_number = info->interface_number;
    device->usage_page = info->usage_page;
    device->usage = info->usage;
    {
        /* FIXME: Is there any way to tell whether this is a Bluetooth device? */
        const Uint16 vendor = device->vendor_id;
        const Uint16 product = device->product_id;
        const Uint16 version = device->version;
        Uint16 *guid16 = (Uint16 *)device->guid.data;

        *guid16++ = SDL_SwapLE16(SDL_HARDWARE_BUS_USB);
        *guid16++ = 0;
        *guid16++ = SDL_SwapLE16(vendor);
        *guid16++ = 0;
        *guid16++ = SDL_SwapLE16(product);
        *guid16++ = 0;
        *guid16++ = SDL_SwapLE16(version);
        *guid16++ = 0;

        /* Note that this is a HIDAPI device for special handling elsewhere */
        device->guid.data[14] = 'h';
        device->guid.data[15] = 0;
    }

    /* Need the device name before getting the driver to know whether to ignore this device */
    if (!device->name) {
        const char *name = SDL_GetCustomJoystickName(device->vendor_id, device->product_id);
        if (name) {
            device->name = SDL_strdup(name);
        }
    }
    if (!device->name && info->manufacturer_string && info->product_string) {
        const char *manufacturer_remapped;
        char *manufacturer_string = SDL_iconv_string("UTF-8", "WCHAR_T", (char*)info->manufacturer_string, (SDL_wcslen(info->manufacturer_string)+1)*sizeof(wchar_t));
        char *product_string = SDL_iconv_string("UTF-8", "WCHAR_T", (char*)info->product_string, (SDL_wcslen(info->product_string)+1)*sizeof(wchar_t));
        if (!manufacturer_string && !product_string) {
            if (sizeof(wchar_t) == sizeof(Uint16)) {
                manufacturer_string = SDL_iconv_string("UTF-8", "UCS-2-INTERNAL", (char*)info->manufacturer_string, (SDL_wcslen(info->manufacturer_string)+1)*sizeof(wchar_t));
                product_string = SDL_iconv_string("UTF-8", "UCS-2-INTERNAL", (char*)info->product_string, (SDL_wcslen(info->product_string)+1)*sizeof(wchar_t));
            } else if (sizeof(wchar_t) == sizeof(Uint32)) {
                manufacturer_string = SDL_iconv_string("UTF-8", "UCS-4-INTERNAL", (char*)info->manufacturer_string, (SDL_wcslen(info->manufacturer_string)+1)*sizeof(wchar_t));
                product_string = SDL_iconv_string("UTF-8", "UCS-4-INTERNAL", (char*)info->product_string, (SDL_wcslen(info->product_string)+1)*sizeof(wchar_t));
            }
        }

        manufacturer_remapped = SDL_GetCustomJoystickManufacturer(manufacturer_string);
        if (manufacturer_remapped != manufacturer_string) {
            SDL_free(manufacturer_string);
            manufacturer_string = SDL_strdup(manufacturer_remapped);
        }

        if (manufacturer_string && product_string) {
            size_t name_size = (SDL_strlen(manufacturer_string) + 1 + SDL_strlen(product_string) + 1);
            device->name = (char *)SDL_malloc(name_size);
            if (device->name) {
                if (SDL_strncasecmp(manufacturer_string, product_string, SDL_strlen(manufacturer_string)) == 0) {
                    SDL_strlcpy(device->name, product_string, name_size);
                } else {
                    SDL_snprintf(device->name, name_size, "%s %s", manufacturer_string, product_string);
                }
            }
        }
        if (manufacturer_string) {
            SDL_free(manufacturer_string);
        }
        if (product_string) {
            SDL_free(product_string);
        }
    }
    if (!device->name) {
        size_t name_size = (6 + 1 + 6 + 1);
        device->name = (char *)SDL_malloc(name_size);
        if (!device->name) {
            SDL_free(device);
            return;
        }
        SDL_snprintf(device->name, name_size, "0x%.4x/0x%.4x", info->vendor_id, info->product_id);
    }

    device->driver = HIDAPI_GetDeviceDriver(device);

    if (device->driver) {
        const char *name = device->driver->GetDeviceName(device->vendor_id, device->product_id);
        if (name) {
            SDL_free(device->name);
            device->name = SDL_strdup(name);
        }
    }

    device->path = SDL_strdup(info->path);
    if (!device->path) {
        SDL_free(device->name);
        SDL_free(device);
        return;
    }

#ifdef DEBUG_HIDAPI
    SDL_Log("Adding HIDAPI device '%s' VID 0x%.4x, PID 0x%.4x, version %d, interface %d, usage page 0x%.4x, usage 0x%.4x, driver = %s\n", device->name, device->vendor_id, device->product_id, device->version, device->interface_number, device->usage_page, device->usage, device->driver ? device->driver->hint : "NONE");
#endif

    /* Add it to the list */
    if (last) {
        last->next = device;
    } else {
        SDL_HIDAPI_devices = device;
    }

    if (device->driver) {
        /* It's a joystick! */
        device->instance_id = SDL_GetNextJoystickInstanceID();

        ++SDL_HIDAPI_numjoysticks;

        SDL_PrivateJoystickAdded(device->instance_id);
    }
}


static void
HIDAPI_DelDevice(SDL_HIDAPI_Device *device, SDL_bool send_event)
{
    SDL_HIDAPI_Device *curr, *last;
    for (curr = SDL_HIDAPI_devices, last = NULL; curr; last = curr, curr = curr->next) {
        if (curr == device) {
            if (last) {
                last->next = curr->next;
            } else {
                SDL_HIDAPI_devices = curr->next;
            }

            if (device->driver && send_event) {
                /* Need to decrement the joystick count before we post the event */
                --SDL_HIDAPI_numjoysticks;

                SDL_PrivateJoystickRemoved(device->instance_id);
            }

            SDL_free(device->name);
            SDL_free(device->path);
            SDL_free(device);
            return;
        }
    }
}

static void
HIDAPI_UpdateDeviceList(void)
{
    SDL_HIDAPI_Device *device;
    struct hid_device_info *devs, *info;

    /* Prepare the existing device list */
    device = SDL_HIDAPI_devices;
    while (device) {
        device->seen = SDL_FALSE;
        device = device->next;
    }

    /* Enumerate the devices */
    if (SDL_HIDAPI_numdrivers > 0) {
        devs = hid_enumerate(0, 0);
        if (devs) {
            for (info = devs; info; info = info->next) {
                device = HIDAPI_GetJoystickByInfo(info->path, info->vendor_id, info->product_id);
                if (device) {
                    device->seen = SDL_TRUE;
                } else {
                    HIDAPI_AddDevice(info);
                }
            }
            hid_free_enumeration(devs);
        }
    }

    /* Remove any devices that weren't seen */
    device = SDL_HIDAPI_devices;
    while (device) {
        SDL_HIDAPI_Device *next = device->next;

        if (!device->seen) {
            HIDAPI_DelDevice(device, SDL_TRUE);
        }
        device = next;
    }
}

SDL_bool
HIDAPI_IsDevicePresent(Uint16 vendor_id, Uint16 product_id, Uint16 version, const char *name)
{
    SDL_HIDAPI_Device *device;

    /* Make sure we're initialized, as this could be called from other drivers during startup */
    if (HIDAPI_JoystickInit() < 0) {
        return SDL_FALSE;
    }

    /* Don't update the device list for devices we know aren't supported */
    if (!HIDAPI_IsDeviceSupported(vendor_id, product_id, version, name)) {
        return SDL_FALSE;
    }

    /* Make sure the device list is completely up to date when we check for device presence */
    HIDAPI_UpdateDeviceList();

    /* Note that this isn't a perfect check - there may be multiple devices with 0 VID/PID,
       or a different name than we have it listed here, etc, but if we support the device
       and we have something similar in our device list, mark it as present.
     */
    device = SDL_HIDAPI_devices;
    while (device) {
        if (device->vendor_id == vendor_id && device->product_id == product_id && device->driver) {
            return SDL_TRUE;
        }
        device = device->next;
    }
    return SDL_FALSE;
}

static void
HIDAPI_JoystickDetect(void)
{
    HIDAPI_UpdateDiscovery();
    if (SDL_HIDAPI_discovery.m_bHaveDevicesChanged) {
        /* FIXME: We probably need to schedule an update in a few seconds as well */
        HIDAPI_UpdateDeviceList();
        SDL_HIDAPI_discovery.m_bHaveDevicesChanged = SDL_FALSE;
    }
}

static const char *
HIDAPI_JoystickGetDeviceName(int device_index)
{
    return HIDAPI_GetJoystickByIndex(device_index)->name;
}

static int
HIDAPI_JoystickGetDevicePlayerIndex(int device_index)
{
    return -1;
}

static SDL_JoystickGUID
HIDAPI_JoystickGetDeviceGUID(int device_index)
{
    return HIDAPI_GetJoystickByIndex(device_index)->guid;
}

static SDL_JoystickID
HIDAPI_JoystickGetDeviceInstanceID(int device_index)
{
    return HIDAPI_GetJoystickByIndex(device_index)->instance_id;
}

static int
HIDAPI_JoystickOpen(SDL_Joystick * joystick, int device_index)
{
    SDL_HIDAPI_Device *device = HIDAPI_GetJoystickByIndex(device_index);
    struct joystick_hwdata *hwdata;

    hwdata = (struct joystick_hwdata *)SDL_calloc(1, sizeof(*hwdata));
    if (!hwdata) {
        return SDL_OutOfMemory();
    }

    hwdata->driver = device->driver;
    hwdata->dev = hid_open_path(device->path, 0);
    if (!hwdata->dev) {
        SDL_free(hwdata);
        return SDL_SetError("Couldn't open HID device %s", device->path);
    }
    hwdata->mutex = SDL_CreateMutex();

    if (!device->driver->Init(joystick, hwdata->dev, device->vendor_id, device->product_id, &hwdata->context)) {
        hid_close(hwdata->dev);
        SDL_free(hwdata);
        return -1;
    }

    joystick->hwdata = hwdata;
    return 0;
}

static int
HIDAPI_JoystickRumble(SDL_Joystick * joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble, Uint32 duration_ms)
{
    struct joystick_hwdata *hwdata = joystick->hwdata;
    SDL_HIDAPI_DeviceDriver *driver = hwdata->driver;
    int result;

    SDL_LockMutex(hwdata->mutex);
    result = driver->Rumble(joystick, hwdata->dev, hwdata->context, low_frequency_rumble, high_frequency_rumble, duration_ms);
    SDL_UnlockMutex(hwdata->mutex);
    return result;
}

static void
HIDAPI_JoystickUpdate(SDL_Joystick * joystick)
{
    struct joystick_hwdata *hwdata = joystick->hwdata;
    SDL_HIDAPI_DeviceDriver *driver = hwdata->driver;
    SDL_bool succeeded;

    SDL_LockMutex(hwdata->mutex);
    succeeded = driver->Update(joystick, hwdata->dev, hwdata->context);
    SDL_UnlockMutex(hwdata->mutex);
    
    if (!succeeded) {
        SDL_HIDAPI_Device *device;
        for (device = SDL_HIDAPI_devices; device; device = device->next) {
            if (device->instance_id == joystick->instance_id) {
                HIDAPI_DelDevice(device, SDL_TRUE);
                break;
            }
        }
    }
}

static void
HIDAPI_JoystickClose(SDL_Joystick * joystick)
{
    struct joystick_hwdata *hwdata = joystick->hwdata;
    SDL_HIDAPI_DeviceDriver *driver = hwdata->driver;
    driver->Quit(joystick, hwdata->dev, hwdata->context);

    hid_close(hwdata->dev);
    SDL_DestroyMutex(hwdata->mutex);
    SDL_free(hwdata);
    joystick->hwdata = NULL;
}

static void
HIDAPI_JoystickQuit(void)
{
    int i;

    HIDAPI_ShutdownDiscovery();

    while (SDL_HIDAPI_devices) {
        HIDAPI_DelDevice(SDL_HIDAPI_devices, SDL_FALSE);
    }
    for (i = 0; i < SDL_arraysize(SDL_HIDAPI_drivers); ++i) {
        SDL_HIDAPI_DeviceDriver *driver = SDL_HIDAPI_drivers[i];
        SDL_DelHintCallback(driver->hint, SDL_HIDAPIDriverHintChanged, NULL);
    }
    SDL_DelHintCallback(SDL_HINT_JOYSTICK_HIDAPI,
                        SDL_HIDAPIDriverHintChanged, NULL);
    SDL_HIDAPI_numjoysticks = 0;

    hid_exit();

    initialized = SDL_FALSE;
}

SDL_JoystickDriver SDL_HIDAPI_JoystickDriver =
{
    HIDAPI_JoystickInit,
    HIDAPI_JoystickGetCount,
    HIDAPI_JoystickDetect,
    HIDAPI_JoystickGetDeviceName,
    HIDAPI_JoystickGetDevicePlayerIndex,
    HIDAPI_JoystickGetDeviceGUID,
    HIDAPI_JoystickGetDeviceInstanceID,
    HIDAPI_JoystickOpen,
    HIDAPI_JoystickRumble,
    HIDAPI_JoystickUpdate,
    HIDAPI_JoystickClose,
    HIDAPI_JoystickQuit,
};

#endif /* SDL_JOYSTICK_HIDAPI */

/* vi: set ts=4 sw=4 expandtab: */