qxcbconnection.cpp

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#include "qxcbconnection.h"
#include "qxcbkeyboard.h"
#include "qxcbscreen.h"
#include "qxcbwindow.h"

#include <QtAlgorithms>
#include <QSocketNotifier>
#include <QtGui/private/qapplication_p.h>
#include <QAbstractEventDispatcher>

#include <QtCore/QDebug>

#include <stdio.h>
#include <errno.h>

#ifdef XCB_USE_XLIB
#include <X11/Xlib.h>
#include <X11/Xlib-xcb.h>
#endif

#ifdef XCB_USE_EGL //don't pull in eglext prototypes
#include <EGL/egl.h>
#endif

#ifdef XCB_USE_DRI2
#include <xcb/dri2.h>
#include <xcb/xfixes.h>
extern "C" {
#include <xf86drm.h>
}
#define MESA_EGL_NO_X11_HEADERS
#define EGL_EGLEXT_PROTOTYPES
#include <EGL/egl.h>
#include <EGL/eglext.h>
#endif

QXcbConnection::QXcbConnection(const char *displayName)
    : m_displayName(displayName ? QByteArray(displayName) : qgetenv("DISPLAY"))
#ifdef XCB_USE_DRI2
    , m_dri2_major(0)
    , m_dri2_minor(0)
    , m_dri2_support_probed(false)
    , m_has_support_for_dri2(false)
#endif
{
    int primaryScreen = 0;

#ifdef XCB_USE_XLIB
    Display *dpy = XOpenDisplay(m_displayName.constData());
    primaryScreen = DefaultScreen(dpy);
    m_connection = XGetXCBConnection(dpy);
    XSetEventQueueOwner(dpy, XCBOwnsEventQueue);
    m_xlib_display = dpy;
#ifdef XCB_USE_EGL
    EGLDisplay eglDisplay = eglGetDisplay(dpy);
    m_egl_display = eglDisplay;
    EGLint major, minor;
    eglBindAPI(EGL_OPENGL_ES_API);
    m_has_egl = eglInitialize(eglDisplay,&major,&minor);
#endif //XCB_USE_EGL
#else
    m_connection = xcb_connect(m_displayName.constData(), &primaryScreen);

#endif //XCB_USE_XLIB
    m_setup = xcb_get_setup(xcb_connection());

    initializeAllAtoms();

    xcb_screen_iterator_t it = xcb_setup_roots_iterator(m_setup);

    int screenNumber = 0;
    while (it.rem) {
        m_screens << new QXcbScreen(this, it.data, screenNumber++);
        xcb_screen_next(&it);
    }

    m_keyboard = new QXcbKeyboard(this);

#ifdef XCB_USE_DRI2
    initializeDri2();
#endif

    QSocketNotifier *notifier = new QSocketNotifier(xcb_get_file_descriptor(xcb_connection()), QSocketNotifier::Read, this);
    connect(notifier, SIGNAL(activated(int)), this, SLOT(processXcbEvents()));

    QAbstractEventDispatcher *dispatcher = QAbstractEventDispatcher::instance(qApp->thread());
    connect(dispatcher, SIGNAL(aboutToBlock()), this, SLOT(processXcbEvents()));

    sync();
}

QXcbConnection::~QXcbConnection()
{
    qDeleteAll(m_screens);

#ifdef XCB_USE_XLIB
    XCloseDisplay((Display *)m_xlib_display);
#else
    xcb_disconnect(xcb_connection());
#endif

    delete m_keyboard;
}

QXcbWindow *platformWindowFromId(xcb_window_t id)
{
    QWidget *widget = QWidget::find(id);
    if (widget)
        return static_cast<QXcbWindow *>(widget->platformWindow());
    return 0;
}

#define HANDLE_PLATFORM_WINDOW_EVENT(event_t, window, handler) \
{ \
    event_t *e = (event_t *)event; \
    if (QXcbWindow *platformWindow = platformWindowFromId(e->window)) { \
        QObjectPrivate *d = QObjectPrivate::get(platformWindow->widget()); \
        if (!d->wasDeleted) \
            platformWindow->handler(e); \
    } \
} \
break;

#define HANDLE_KEYBOARD_EVENT(event_t, handler) \
{ \
    event_t *e = (event_t *)event; \
    if (QXcbWindow *platformWindow = platformWindowFromId(e->event)) \
        m_keyboard->handler(platformWindow->widget(), e); \
} \
break;

//#define XCB_EVENT_DEBUG

void printXcbEvent(const char *message, xcb_generic_event_t *event)
{
#ifdef XCB_EVENT_DEBUG
#define PRINT_XCB_EVENT(ev) \
    case ev: \
        printf("%s: %d - %s - sequence: %d\n", message, int(ev), #ev, event->sequence); \
        break;

    switch (event->response_type & ~0x80) {
    PRINT_XCB_EVENT(XCB_KEY_PRESS);
    PRINT_XCB_EVENT(XCB_KEY_RELEASE);
    PRINT_XCB_EVENT(XCB_BUTTON_PRESS);
    PRINT_XCB_EVENT(XCB_BUTTON_RELEASE);
    PRINT_XCB_EVENT(XCB_MOTION_NOTIFY);
    PRINT_XCB_EVENT(XCB_ENTER_NOTIFY);
    PRINT_XCB_EVENT(XCB_LEAVE_NOTIFY);
    PRINT_XCB_EVENT(XCB_FOCUS_IN);
    PRINT_XCB_EVENT(XCB_FOCUS_OUT);
    PRINT_XCB_EVENT(XCB_KEYMAP_NOTIFY);
    PRINT_XCB_EVENT(XCB_EXPOSE);
    PRINT_XCB_EVENT(XCB_GRAPHICS_EXPOSURE);
    PRINT_XCB_EVENT(XCB_VISIBILITY_NOTIFY);
    PRINT_XCB_EVENT(XCB_CREATE_NOTIFY);
    PRINT_XCB_EVENT(XCB_DESTROY_NOTIFY);
    PRINT_XCB_EVENT(XCB_UNMAP_NOTIFY);
    PRINT_XCB_EVENT(XCB_MAP_NOTIFY);
    PRINT_XCB_EVENT(XCB_MAP_REQUEST);
    PRINT_XCB_EVENT(XCB_REPARENT_NOTIFY);
    PRINT_XCB_EVENT(XCB_CONFIGURE_NOTIFY);
    PRINT_XCB_EVENT(XCB_CONFIGURE_REQUEST);
    PRINT_XCB_EVENT(XCB_GRAVITY_NOTIFY);
    PRINT_XCB_EVENT(XCB_RESIZE_REQUEST);
    PRINT_XCB_EVENT(XCB_CIRCULATE_NOTIFY);
    PRINT_XCB_EVENT(XCB_CIRCULATE_REQUEST);
    PRINT_XCB_EVENT(XCB_PROPERTY_NOTIFY);
    PRINT_XCB_EVENT(XCB_SELECTION_CLEAR);
    PRINT_XCB_EVENT(XCB_SELECTION_REQUEST);
    PRINT_XCB_EVENT(XCB_SELECTION_NOTIFY);
    PRINT_XCB_EVENT(XCB_COLORMAP_NOTIFY);
    PRINT_XCB_EVENT(XCB_CLIENT_MESSAGE);
    PRINT_XCB_EVENT(XCB_MAPPING_NOTIFY);
    default:
        printf("%s: unknown event - response_type: %d - sequence: %d\n", message, int(event->response_type & ~0x80), int(event->sequence));
    }
#else
    Q_UNUSED(message);
    Q_UNUSED(event);
#endif
}

const char *xcb_errors[] =
{
    "Success",
    "BadRequest",
    "BadValue",
    "BadWindow",
    "BadPixmap",
    "BadAtom",
    "BadCursor",
    "BadFont",
    "BadMatch",
    "BadDrawable",
    "BadAccess",
    "BadAlloc",
    "BadColor",
    "BadGC",
    "BadIDChoice",
    "BadName",
    "BadLength",
    "BadImplementation",
    "Unknown"
};

const char *xcb_protocol_request_codes[] =
{
    "Null",
    "CreateWindow",
    "ChangeWindowAttributes",
    "GetWindowAttributes",
    "DestroyWindow",
    "DestroySubwindows",
    "ChangeSaveSet",
    "ReparentWindow",
    "MapWindow",
    "MapSubwindows",
    "UnmapWindow",
    "UnmapSubwindows",
    "ConfigureWindow",
    "CirculateWindow",
    "GetGeometry",
    "QueryTree",
    "InternAtom",
    "GetAtomName",
    "ChangeProperty",
    "DeleteProperty",
    "GetProperty",
    "ListProperties",
    "SetSelectionOwner",
    "GetSelectionOwner",
    "ConvertSelection",
    "SendEvent",
    "GrabPointer",
    "UngrabPointer",
    "GrabButton",
    "UngrabButton",
    "ChangeActivePointerGrab",
    "GrabKeyboard",
    "UngrabKeyboard",
    "GrabKey",
    "UngrabKey",
    "AllowEvents",
    "GrabServer",
    "UngrabServer",
    "QueryPointer",
    "GetMotionEvents",
    "TranslateCoords",
    "WarpPointer",
    "SetInputFocus",
    "GetInputFocus",
    "QueryKeymap",
    "OpenFont",
    "CloseFont",
    "QueryFont",
    "QueryTextExtents",
    "ListFonts",
    "ListFontsWithInfo",
    "SetFontPath",
    "GetFontPath",
    "CreatePixmap",
    "FreePixmap",
    "CreateGC",
    "ChangeGC",
    "CopyGC",
    "SetDashes",
    "SetClipRectangles",
    "FreeGC",
    "ClearArea",
    "CopyArea",
    "CopyPlane",
    "PolyPoint",
    "PolyLine",
    "PolySegment",
    "PolyRectangle",
    "PolyArc",
    "FillPoly",
    "PolyFillRectangle",
    "PolyFillArc",
    "PutImage",
    "GetImage",
    "PolyText8",
    "PolyText16",
    "ImageText8",
    "ImageText16",
    "CreateColormap",
    "FreeColormap",
    "CopyColormapAndFree",
    "InstallColormap",
    "UninstallColormap",
    "ListInstalledColormaps",
    "AllocColor",
    "AllocNamedColor",
    "AllocColorCells",
    "AllocColorPlanes",
    "FreeColors",
    "StoreColors",
    "StoreNamedColor",
    "QueryColors",
    "LookupColor",
    "CreateCursor",
    "CreateGlyphCursor",
    "FreeCursor",
    "RecolorCursor",
    "QueryBestSize",
    "QueryExtension",
    "ListExtensions",
    "ChangeKeyboardMapping",
    "GetKeyboardMapping",
    "ChangeKeyboardControl",
    "GetKeyboardControl",
    "Bell",
    "ChangePointerControl",
    "GetPointerControl",
    "SetScreenSaver",
    "GetScreenSaver",
    "ChangeHosts",
    "ListHosts",
    "SetAccessControl",
    "SetCloseDownMode",
    "KillClient",
    "RotateProperties",
    "ForceScreenSaver",
    "SetPointerMapping",
    "GetPointerMapping",
    "SetModifierMapping",
    "GetModifierMapping",
    "Unknown"
};

#ifdef Q_XCB_DEBUG
void QXcbConnection::log(const char *file, int line, int sequence)
{
    CallInfo info;
    info.sequence = sequence;
    info.file = file;
    info.line = line;
    m_callLog << info;
}
#endif

void QXcbConnection::handleXcbError(xcb_generic_error_t *error)
{
    uint clamped_error_code = qMin<uint>(error->error_code, (sizeof(xcb_errors) / sizeof(xcb_errors[0])) - 1);
    uint clamped_major_code = qMin<uint>(error->major_code, (sizeof(xcb_protocol_request_codes) / sizeof(xcb_protocol_request_codes[0])) - 1);

    printf("XCB error: %d (%s), sequence: %d, resource id: %d, major code: %d (%s), minor code: %d\n",
           int(error->error_code), xcb_errors[clamped_error_code],
           int(error->sequence), int(error->resource_id),
           int(error->major_code), xcb_protocol_request_codes[clamped_major_code],
           int(error->minor_code));
#ifdef Q_XCB_DEBUG
    int i = 0;
    for (; i < m_callLog.size(); ++i) {
        if (m_callLog.at(i).sequence == error->sequence) {
            printf("Caused by: %s:%d\n", qPrintable(m_callLog.at(i).file), m_callLog.at(i).line);
            break;
        } else if (m_callLog.at(i).sequence > error->sequence) {
            printf("Caused some time before: %s:%d\n", qPrintable(m_callLog.at(i).file), m_callLog.at(i).line);
            if (i > 0)
                printf("and after: %s:%d\n", qPrintable(m_callLog.at(i-1).file), m_callLog.at(i-1).line);
            break;
        }
    }
    if (i == m_callLog.size() && !m_callLog.isEmpty())
        printf("Caused some time after: %s:%d\n", qPrintable(m_callLog.first().file), m_callLog.first().line);
#endif
}

void QXcbConnection::processXcbEvents()
{
    while (xcb_generic_event_t *event = xcb_poll_for_event(xcb_connection())) {
        bool handled = true;

        uint response_type = event->response_type & ~0x80;

        if (!response_type) {
            handleXcbError((xcb_generic_error_t *)event);
            continue;
        }

#ifdef Q_XCB_DEBUG
        {
            int i = 0;
            for (; i < m_callLog.size(); ++i)
                if (m_callLog.at(i).sequence >= event->sequence)
                    break;
            m_callLog.remove(0, i);
        }
#endif

        switch (response_type) {
        case XCB_EXPOSE:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_expose_event_t, window, handleExposeEvent);
        case XCB_BUTTON_PRESS:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_button_press_event_t, event, handleButtonPressEvent);
        case XCB_BUTTON_RELEASE:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_button_release_event_t, event, handleButtonReleaseEvent);
        case XCB_MOTION_NOTIFY:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_motion_notify_event_t, event, handleMotionNotifyEvent);
        case XCB_CONFIGURE_NOTIFY:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_configure_notify_event_t, event, handleConfigureNotifyEvent);
        case XCB_CLIENT_MESSAGE:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_client_message_event_t, window, handleClientMessageEvent);
        case XCB_ENTER_NOTIFY:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_enter_notify_event_t, event, handleEnterNotifyEvent);
        case XCB_LEAVE_NOTIFY:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_leave_notify_event_t, event, handleLeaveNotifyEvent);
        case XCB_FOCUS_IN:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_focus_in_event_t, event, handleFocusInEvent);
        case XCB_FOCUS_OUT:
            HANDLE_PLATFORM_WINDOW_EVENT(xcb_focus_out_event_t, event, handleFocusOutEvent);
        case XCB_KEY_PRESS:
            HANDLE_KEYBOARD_EVENT(xcb_key_press_event_t, handleKeyPressEvent);
        case XCB_KEY_RELEASE:
            HANDLE_KEYBOARD_EVENT(xcb_key_release_event_t, handleKeyReleaseEvent);
        case XCB_MAPPING_NOTIFY:
            m_keyboard->handleMappingNotifyEvent((xcb_mapping_notify_event_t *)event);
            break;
        default:
            handled = false;
            break;
        }
        if (handled)
            printXcbEvent("Handled XCB event", event);
        else
            printXcbEvent("Unhandled XCB event", event);
    }

    xcb_flush(xcb_connection());
}

static const char * xcb_atomnames = {
    // window-manager <-> client protocols
    "WM_PROTOCOLS\0"
    "WM_DELETE_WINDOW\0"
    "WM_TAKE_FOCUS\0"
    "_NET_WM_PING\0"
    "_NET_WM_CONTEXT_HELP\0"
    "_NET_WM_SYNC_REQUEST\0"
    "_NET_WM_SYNC_REQUEST_COUNTER\0"

    // ICCCM window state
    "WM_STATE\0"
    "WM_CHANGE_STATE\0"

    // Session management
    "WM_CLIENT_LEADER\0"
    "WM_WINDOW_ROLE\0"
    "SM_CLIENT_ID\0"

    // Clipboard
    "CLIPBOARD\0"
    "INCR\0"
    "TARGETS\0"
    "MULTIPLE\0"
    "TIMESTAMP\0"
    "SAVE_TARGETS\0"
    "CLIP_TEMPORARY\0"
    "_QT_SELECTION\0"
    "_QT_CLIPBOARD_SENTINEL\0"
    "_QT_SELECTION_SENTINEL\0"
    "CLIPBOARD_MANAGER\0"

    "RESOURCE_MANAGER\0"

    "_XSETROOT_ID\0"

    "_QT_SCROLL_DONE\0"
    "_QT_INPUT_ENCODING\0"

    "_MOTIF_WM_HINTS\0"

    "DTWM_IS_RUNNING\0"
    "ENLIGHTENMENT_DESKTOP\0"
    "_DT_SAVE_MODE\0"
    "_SGI_DESKS_MANAGER\0"

    // EWMH (aka NETWM)
    "_NET_SUPPORTED\0"
    "_NET_VIRTUAL_ROOTS\0"
    "_NET_WORKAREA\0"

    "_NET_MOVERESIZE_WINDOW\0"
    "_NET_WM_MOVERESIZE\0"

    "_NET_WM_NAME\0"
    "_NET_WM_ICON_NAME\0"
    "_NET_WM_ICON\0"

    "_NET_WM_PID\0"

    "_NET_WM_WINDOW_OPACITY\0"

    "_NET_WM_STATE\0"
    "_NET_WM_STATE_ABOVE\0"
    "_NET_WM_STATE_BELOW\0"
    "_NET_WM_STATE_FULLSCREEN\0"
    "_NET_WM_STATE_MAXIMIZED_HORZ\0"
    "_NET_WM_STATE_MAXIMIZED_VERT\0"
    "_NET_WM_STATE_MODAL\0"
    "_NET_WM_STATE_STAYS_ON_TOP\0"
    "_NET_WM_STATE_DEMANDS_ATTENTION\0"

    "_NET_WM_USER_TIME\0"
    "_NET_WM_USER_TIME_WINDOW\0"
    "_NET_WM_FULL_PLACEMENT\0"

    "_NET_WM_WINDOW_TYPE\0"
    "_NET_WM_WINDOW_TYPE_DESKTOP\0"
    "_NET_WM_WINDOW_TYPE_DOCK\0"
    "_NET_WM_WINDOW_TYPE_TOOLBAR\0"
    "_NET_WM_WINDOW_TYPE_MENU\0"
    "_NET_WM_WINDOW_TYPE_UTILITY\0"
    "_NET_WM_WINDOW_TYPE_SPLASH\0"
    "_NET_WM_WINDOW_TYPE_DIALOG\0"
    "_NET_WM_WINDOW_TYPE_DROPDOWN_MENU\0"
    "_NET_WM_WINDOW_TYPE_POPUP_MENU\0"
    "_NET_WM_WINDOW_TYPE_TOOLTIP\0"
    "_NET_WM_WINDOW_TYPE_NOTIFICATION\0"
    "_NET_WM_WINDOW_TYPE_COMBO\0"
    "_NET_WM_WINDOW_TYPE_DND\0"
    "_NET_WM_WINDOW_TYPE_NORMAL\0"
    "_KDE_NET_WM_WINDOW_TYPE_OVERRIDE\0"

    "_KDE_NET_WM_FRAME_STRUT\0"

    "_NET_STARTUP_INFO\0"
    "_NET_STARTUP_INFO_BEGIN\0"

    "_NET_SUPPORTING_WM_CHECK\0"

    "_NET_WM_CM_S0\0"

    "_NET_SYSTEM_TRAY_VISUAL\0"

    "_NET_ACTIVE_WINDOW\0"

    // Property formats
    "COMPOUND_TEXT\0"
    "TEXT\0"
    "UTF8_STRING\0"

    // xdnd
    "XdndEnter\0"
    "XdndPosition\0"
    "XdndStatus\0"
    "XdndLeave\0"
    "XdndDrop\0"
    "XdndFinished\0"
    "XdndTypeList\0"
    "XdndActionList\0"

    "XdndSelection\0"

    "XdndAware\0"
    "XdndProxy\0"

    "XdndActionCopy\0"
    "XdndActionLink\0"
    "XdndActionMove\0"
    "XdndActionPrivate\0"

    // Motif DND
    "_MOTIF_DRAG_AND_DROP_MESSAGE\0"
    "_MOTIF_DRAG_INITIATOR_INFO\0"
    "_MOTIF_DRAG_RECEIVER_INFO\0"
    "_MOTIF_DRAG_WINDOW\0"
    "_MOTIF_DRAG_TARGETS\0"

    "XmTRANSFER_SUCCESS\0"
    "XmTRANSFER_FAILURE\0"

    // Xkb
    "_XKB_RULES_NAMES\0"

    // XEMBED
    "_XEMBED\0"
    "_XEMBED_INFO\0"

    // Wacom old. (before version 0.10)
    "Wacom Stylus\0"
    "Wacom Cursor\0"
    "Wacom Eraser\0"

    // Tablet
    "STYLUS\0"
    "ERASER\0"
};

xcb_atom_t QXcbConnection::atom(QXcbAtom::Atom atom)
{
    return m_allAtoms[atom];
}

void QXcbConnection::initializeAllAtoms() {
    const char *names[QXcbAtom::NAtoms];
    const char *ptr = xcb_atomnames;

    int i = 0;
    while (*ptr) {
        names[i++] = ptr;
        while (*ptr)
            ++ptr;
        ++ptr;
    }

    Q_ASSERT(i == QXcbAtom::NPredefinedAtoms);

    QByteArray settings_atom_name("_QT_SETTINGS_TIMESTAMP_");
    settings_atom_name += m_displayName;
    names[i++] = settings_atom_name;

    xcb_intern_atom_cookie_t cookies[QXcbAtom::NAtoms];

    Q_ASSERT(i == QXcbAtom::NAtoms);
    for (i = 0; i < QXcbAtom::NAtoms; ++i)
        cookies[i] = xcb_intern_atom(xcb_connection(), false, strlen(names[i]), names[i]);

    for (i = 0; i < QXcbAtom::NAtoms; ++i)
        m_allAtoms[i] = xcb_intern_atom_reply(xcb_connection(), cookies[i], 0)->atom;
}

void QXcbConnection::sync()
{
    // from xcb_aux_sync
    xcb_get_input_focus_cookie_t cookie = Q_XCB_CALL(xcb_get_input_focus(xcb_connection()));
    free(xcb_get_input_focus_reply(xcb_connection(), cookie, 0));
}

#if defined(XCB_USE_EGL)
bool QXcbConnection::hasEgl() const
{
    return m_has_egl;
}
#endif // defined(XCB_USE_EGL)

#ifdef XCB_USE_DRI2
void QXcbConnection::initializeDri2()
{
    xcb_dri2_connect_cookie_t connect_cookie = xcb_dri2_connect_unchecked (m_connection,
                                                                           m_screens[0]->root(),
                                                                           XCB_DRI2_DRIVER_TYPE_DRI);

    xcb_dri2_connect_reply_t *connect = xcb_dri2_connect_reply (m_connection,
                                                                connect_cookie, NULL);

    if (! connect || connect->driver_name_length + connect->device_name_length == 0) {
        qDebug() << "Failed to connect to dri2";
        return;
    }

    m_dri2_device_name = QByteArray(xcb_dri2_connect_device_name (connect),
                                                    xcb_dri2_connect_device_name_length (connect));
    delete connect;

    int fd = open(m_dri2_device_name.constData(), O_RDWR);
    if (fd < 0) {
        qDebug() << "InitializeDri2: Could'nt open device << dri2DeviceName";
        m_dri2_device_name = QByteArray();
        return;
    }

    drm_magic_t magic;
    if (drmGetMagic(fd, &magic)) {
        qDebug() << "Failed to get drmMagic";
        return;
    }

    xcb_dri2_authenticate_cookie_t authenticate_cookie = xcb_dri2_authenticate_unchecked(m_connection,
                                                                                         m_screens[0]->root(), magic);
    xcb_dri2_authenticate_reply_t *authenticate = xcb_dri2_authenticate_reply(m_connection,
                                                                              authenticate_cookie, NULL);
    if (authenticate == NULL || !authenticate->authenticated) {
        fprintf(stderr, "DRI2: failed to authenticate\n");
        free(authenticate);
        return;
    }

    delete authenticate;

    EGLDisplay display = eglGetDRMDisplayMESA(fd);
    if (!display) {
        fprintf(stderr, "failed to create display\n");
        return;
    }

    m_egl_display = display;
    EGLint major,minor;
    if (!eglInitialize(display, &major, &minor)) {
        fprintf(stderr, "failed to initialize display\n");
        return;
    }
}

bool QXcbConnection::hasSupportForDri2() const
{
    if (!m_dri2_support_probed) {
        xcb_generic_error_t *error = 0;

        xcb_prefetch_extension_data (m_connection, &xcb_xfixes_id);
        xcb_prefetch_extension_data (m_connection, &xcb_dri2_id);

        xcb_xfixes_query_version_cookie_t xfixes_query_cookie = xcb_xfixes_query_version(m_connection,
                                                                                         XCB_XFIXES_MAJOR_VERSION,
                                                                                         XCB_XFIXES_MINOR_VERSION);

        xcb_dri2_query_version_cookie_t dri2_query_cookie = xcb_dri2_query_version (m_connection,
                                                                                    XCB_DRI2_MAJOR_VERSION,
                                                                                    XCB_DRI2_MINOR_VERSION);

        xcb_xfixes_query_version_reply_t *xfixes_query = xcb_xfixes_query_version_reply (m_connection,
                                                                                         xfixes_query_cookie, &error);
        if (!xfixes_query || error || xfixes_query->major_version < 2) {
            delete error;
            delete xfixes_query;
            return false;
        }
        delete xfixes_query;

        xcb_dri2_query_version_reply_t *dri2_query = xcb_dri2_query_version_reply (m_connection,
                                                                                   dri2_query_cookie, &error);
        if (!dri2_query || error) {
            delete error;
            delete dri2_query;
            return false;
        }

        QXcbConnection *that = const_cast<QXcbConnection *>(this);
        that->m_dri2_major = dri2_query->major_version;
        that->m_dri2_minor = dri2_query->minor_version;

        that->m_has_support_for_dri2 = true;
        that->m_dri2_support_probed = true;
    }
    return m_has_support_for_dri2;
}
#endif //XCB_USE_DRI2