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#include "qeglfshooks.h"

#include <qpa/qwindowsysteminterface.h>
#include <qpa/qplatformwindow.h>
#include <QThread>

#include <X11/Xlib.h>
#include <X11/Xlib-xcb.h>
#include <xcb/xcb.h>

QT_BEGIN_NAMESPACE

class QEglFSX11Hooks;

class EventReader : public QThread
{
public:
    EventReader(QEglFSX11Hooks *hooks)
        : m_hooks(hooks) { }

    void run();

private:
    QEglFSX11Hooks *m_hooks;
};

namespace Atoms {
    enum {
        _NET_WM_NAME = 0,
        UTF8_STRING,
        WM_PROTOCOLS,
        WM_DELETE_WINDOW,
        _NET_WM_STATE,
        _NET_WM_STATE_FULLSCREEN,

        N_ATOMS
    };
}

class QEglFSX11Hooks : public QEglFSHooks
{
public:
    QEglFSX11Hooks() : m_connection(0), m_window(0), m_eventReader(0) {}

    virtual void platformInit();
    virtual void platformDestroy();
    virtual EGLNativeDisplayType platformDisplay() const;
    virtual QSize screenSize() const;
    virtual EGLNativeWindowType createNativeWindow(QPlatformWindow *window,
                                                   const QSize &size,
                                                   const QSurfaceFormat &format);
    virtual void destroyNativeWindow(EGLNativeWindowType window);
    virtual bool hasCapability(QPlatformIntegration::Capability cap) const;

    xcb_connection_t *connection() { return m_connection; }
    const xcb_atom_t *atoms() const { return m_atoms; }
    QPlatformWindow *platformWindow() { return m_platformWindow; }

private:
    void sendConnectionEvent(xcb_atom_t a);

    Display *m_display;
    xcb_connection_t *m_connection;
    xcb_atom_t m_atoms[Atoms::N_ATOMS];
    xcb_window_t m_window;
    EventReader *m_eventReader;
    xcb_window_t m_connectionEventListener;
    QPlatformWindow *m_platformWindow;
    mutable QSize m_screenSize;
};

QAtomicInt running;

static Qt::MouseButtons translateMouseButtons(int s)
{
    Qt::MouseButtons ret = 0;
    if (s & XCB_BUTTON_MASK_1)
        ret |= Qt::LeftButton;
    if (s & XCB_BUTTON_MASK_2)
        ret |= Qt::MidButton;
    if (s & XCB_BUTTON_MASK_3)
        ret |= Qt::RightButton;
    return ret;
}

static Qt::MouseButton translateMouseButton(xcb_button_t s)
{
    switch (s) {
    case 1: return Qt::LeftButton;
    case 2: return Qt::MidButton;
    case 3: return Qt::RightButton;
    // Button values 4-7 were already handled as Wheel events, and won't occur here.
    case 8: return Qt::BackButton;      // Also known as Qt::ExtraButton1
    case 9: return Qt::ForwardButton;   // Also known as Qt::ExtraButton2
    case 10: return Qt::ExtraButton3;
    case 11: return Qt::ExtraButton4;
    case 12: return Qt::ExtraButton5;
    case 13: return Qt::ExtraButton6;
    case 14: return Qt::ExtraButton7;
    case 15: return Qt::ExtraButton8;
    case 16: return Qt::ExtraButton9;
    case 17: return Qt::ExtraButton10;
    case 18: return Qt::ExtraButton11;
    case 19: return Qt::ExtraButton12;
    case 20: return Qt::ExtraButton13;
    case 21: return Qt::ExtraButton14;
    case 22: return Qt::ExtraButton15;
    case 23: return Qt::ExtraButton16;
    case 24: return Qt::ExtraButton17;
    case 25: return Qt::ExtraButton18;
    case 26: return Qt::ExtraButton19;
    case 27: return Qt::ExtraButton20;
    case 28: return Qt::ExtraButton21;
    case 29: return Qt::ExtraButton22;
    case 30: return Qt::ExtraButton23;
    case 31: return Qt::ExtraButton24;
    default: return Qt::NoButton;
    }
}

void EventReader::run()
{
    Qt::MouseButtons buttons;

    xcb_generic_event_t *event;
    while (running.load() && (event = xcb_wait_for_event(m_hooks->connection()))) {
        uint response_type = event->response_type & ~0x80;
        switch (response_type) {
        case XCB_BUTTON_PRESS: {
            xcb_button_press_event_t *press = (xcb_button_press_event_t *)event;
            QPoint p(press->event_x, press->event_y);
            buttons = (buttons & ~0x7) | translateMouseButtons(press->state);
            buttons |= translateMouseButton(press->detail);
            QWindowSystemInterface::handleMouseEvent(0, press->time, p, p, buttons);
            break;
            }
        case XCB_BUTTON_RELEASE: {
            xcb_button_release_event_t *release = (xcb_button_release_event_t *)event;
            QPoint p(release->event_x, release->event_y);
            buttons = (buttons & ~0x7) | translateMouseButtons(release->state);
            buttons &= ~translateMouseButton(release->detail);
            QWindowSystemInterface::handleMouseEvent(0, release->time, p, p, buttons);
            break;
            }
        case XCB_MOTION_NOTIFY: {
            xcb_motion_notify_event_t *motion = (xcb_motion_notify_event_t *)event;
            QPoint p(motion->event_x, motion->event_y);
            QWindowSystemInterface::handleMouseEvent(0, motion->time, p, p, buttons);
            break;
            }
        case XCB_CLIENT_MESSAGE: {
            xcb_client_message_event_t *client = (xcb_client_message_event_t *) event;
            const xcb_atom_t *atoms = m_hooks->atoms();
            if (client->format == 32
                && client->type == atoms[Atoms::WM_PROTOCOLS]
                && client->data.data32[0] == atoms[Atoms::WM_DELETE_WINDOW]) {
                QWindow *window = m_hooks->platformWindow() ? m_hooks->platformWindow()->window() : 0;
                if (window)
                    QWindowSystemInterface::handleCloseEvent(window);
            }
            break;
            }
        default:
            break;
        }
    }
}

void QEglFSX11Hooks::sendConnectionEvent(xcb_atom_t a)
{
    xcb_client_message_event_t event;
    memset(&event, 0, sizeof(event));

    event.response_type = XCB_CLIENT_MESSAGE;
    event.format = 32;
    event.sequence = 0;
    event.window = m_connectionEventListener;
    event.type = a;

    xcb_send_event(m_connection, false, m_connectionEventListener, XCB_EVENT_MASK_NO_EVENT, (const char *)&event);
    xcb_flush(m_connection);
}

void QEglFSX11Hooks::platformInit()
{
    m_display = XOpenDisplay(0);
    if (!m_display)
        qFatal("Could not open display");

    XSetEventQueueOwner(m_display, XCBOwnsEventQueue);
    m_connection = XGetXCBConnection(m_display);

    running.ref();

    xcb_screen_iterator_t it = xcb_setup_roots_iterator(xcb_get_setup(m_connection));

    m_connectionEventListener = xcb_generate_id(m_connection);
    xcb_create_window(m_connection, XCB_COPY_FROM_PARENT,
                      m_connectionEventListener, it.data->root,
                      0, 0, 1, 1, 0, XCB_WINDOW_CLASS_INPUT_ONLY,
                      it.data->root_visual, 0, 0);

    m_eventReader = new EventReader(this);
    m_eventReader->start();
}

void QEglFSX11Hooks::platformDestroy()
{
    running.deref();

    sendConnectionEvent(XCB_ATOM_NONE);

    m_eventReader->wait();
    delete m_eventReader;
    m_eventReader = 0;

    XCloseDisplay(m_display);
    m_display = 0;
    m_connection = 0;
}

EGLNativeDisplayType QEglFSX11Hooks::platformDisplay() const
{
    return m_display;
}

QSize QEglFSX11Hooks::screenSize() const
{
    if (m_screenSize.isEmpty()) {
        QList<QByteArray> env = qgetenv("EGLFS_X11_SIZE").split('x');
        if (env.length() == 2) {
            m_screenSize = QSize(env.at(0).toInt(), env.at(1).toInt());
        } else {
            m_screenSize = QSize(640, 480);
            qDebug("EGLFS_X11_SIZE not set, falling back to 640x480");
        }
    }
    return m_screenSize;
}

EGLNativeWindowType QEglFSX11Hooks::createNativeWindow(QPlatformWindow *platformWindow,
                                                       const QSize &size,
                                                       const QSurfaceFormat &format)
{
    Q_UNUSED(format);

    m_platformWindow = platformWindow;

    xcb_screen_iterator_t it = xcb_setup_roots_iterator(xcb_get_setup(m_connection));
    m_window = xcb_generate_id(m_connection);
    xcb_create_window(m_connection, XCB_COPY_FROM_PARENT, m_window, it.data->root,
                      0, 0, size.width(), size.height(), 0,
                      XCB_WINDOW_CLASS_INPUT_OUTPUT, it.data->root_visual,
                      0, 0);

    xcb_map_window(m_connection, m_window);

    xcb_intern_atom_cookie_t cookies[Atoms::N_ATOMS];
    static const char *atomNames[Atoms::N_ATOMS] = {
        "_NET_WM_NAME",
        "UTF8_STRING",
        "WM_PROTOCOLS",
        "WM_DELETE_WINDOW",
        "_NET_WM_STATE",
        "_NET_WM_STATE_FULLSCREEN"
    };

    for (int i = 0; i < Atoms::N_ATOMS; ++i) {
        cookies[i] = xcb_intern_atom(m_connection, false, strlen(atomNames[i]), atomNames[i]);
        xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(m_connection, cookies[i], 0);
        m_atoms[i] = reply->atom;
        free(reply);
    }

    // Set window title
    xcb_change_property(m_connection, XCB_PROP_MODE_REPLACE, m_window,
                        m_atoms[Atoms::_NET_WM_NAME], m_atoms[Atoms::UTF8_STRING], 8, 5, "EGLFS");

    // Enable WM_DELETE_WINDOW
    xcb_change_property(m_connection, XCB_PROP_MODE_REPLACE, m_window,
                        m_atoms[Atoms::WM_PROTOCOLS], XCB_ATOM_ATOM, 32, 1, &m_atoms[Atoms::WM_DELETE_WINDOW]);

    if (qgetenv("EGLFS_X11_FULLSCREEN").toInt()) {
        // Go fullscreen. The QScreen and QWindow size is controlled by EGLFS_X11_SIZE regardless,
        // this is just the native window.
        xcb_change_property(m_connection, XCB_PROP_MODE_REPLACE, m_window,
                            m_atoms[Atoms::_NET_WM_STATE], XCB_ATOM_ATOM, 32, 1, &m_atoms[Atoms::_NET_WM_STATE_FULLSCREEN]);
    }

    xcb_flush(m_connection);

    return m_window;
}

void QEglFSX11Hooks::destroyNativeWindow(EGLNativeWindowType window)
{
    xcb_destroy_window(m_connection, window);
}

bool QEglFSX11Hooks::hasCapability(QPlatformIntegration::Capability cap) const
{
    Q_UNUSED(cap);
    return false;
}

static QEglFSX11Hooks eglFSX11Hooks;
QEglFSHooks *platformHooks = &eglFSX11Hooks;

QT_END_NAMESPACE