xwrapper.cpp

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/

#include "xwrapper.h"
#include <limits>
#include <type_traits>
#include <bit>
#include <QString>
#include <QPixmap>
#include <QIcon>
#include <QApplication>
#include <QWidget>
#include <QAbstractEventDispatcher>
#include <QtDebug>
#include <QScreen>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>
#include <xcb/xcb.h>
#include <util/sll/qtutil.h>

namespace LC::Util
{
    const int SourcePager = 2;

    const int StateRemove = 0;
    const int StateAdd = 1;

    XWrapper::XWrapper ()
    {
        const auto x11app = qGuiApp->nativeInterface<QNativeInterface::QX11Application> ();
        if (!x11app)
            throw std::runtime_error { "XWrapper used on non-X11" };

        Conn_ = x11app->connection ();
        Display_ = x11app->display ();
        AppWin_ = DefaultRootWindow (Display_);

        if (!Display_)
            throw std::runtime_error { "No X11 display" };

        QAbstractEventDispatcher::instance ()->installNativeEventFilter (this);

        const uint32_t rootEvents [] =
        {
            XCB_EVENT_MASK_STRUCTURE_NOTIFY |
                XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY |
                XCB_EVENT_MASK_PROPERTY_CHANGE
        };
        xcb_change_window_attributes (Conn_,
                AppWin_, XCB_CW_EVENT_MASK, rootEvents);
    }

    XWrapper& XWrapper::Instance ()
    {
        static XWrapper w;
        return w;
    }

    xcb_connection_t* XWrapper::GetConnection () const
    {
        return Conn_;
    }

    Display* XWrapper::GetDisplay () const
    {
        return Display_;
    }

    Window XWrapper::GetRootWindow () const
    {
        return AppWin_;
    }

    bool XWrapper::nativeEventFilter (const QByteArray& eventType, void *msg, qintptr*)
    {
        if (eventType != "xcb_generic_event_t")
            return false;

        const auto ev = static_cast<xcb_generic_event_t*> (msg);
        if ((ev->response_type & ~0x80) == XCB_PROPERTY_NOTIFY)
            HandlePropNotify (static_cast<xcb_property_notify_event_t*> (msg));

        return false;
    }

    namespace
    {
        template<typename T>
        struct IsDoublePtr : std::false_type {};

        template<typename T>
        struct IsDoublePtr<T**> : std::true_type {};

        template<typename T>
        class Guarded
        {
            T *Data_ = nullptr;
        public:
            Guarded () = default;

            Guarded (const Guarded&) = delete;
            Guarded& operator= (const Guarded&) = delete;

            Guarded (Guarded&& other) noexcept
            : Data_ { other.Data_ }
            {
                other.Data_ = nullptr;
            }

            Guarded& operator= (Guarded&& other) noexcept
            {
                std::swap (Data_, other.Data_);
                return *this;
            }

            ~Guarded () noexcept
            {
                if (Data_)
                    XFree (Data_);
            }

            T** Get (bool clear = true) noexcept
            {
                if (clear && Data_)
                    XFree (Data_);
                return &Data_;
            }

            template<typename U>
            U GetAs (bool clear = true) noexcept
            {
                if (clear && Data_)
                    XFree (Data_);
                return IsDoublePtr<U>::value ?
                        reinterpret_cast<U> (&Data_) :
                        reinterpret_cast<U> (Data_);
            }

            T operator[] (size_t idx) const noexcept
            {
                return Data_ [idx];
            }

            T& operator[] (size_t idx) noexcept
            {
                return Data_ [idx];
            }

            explicit operator bool () const noexcept
            {
                return Data_ != nullptr;
            }

            bool operator! () const noexcept
            {
                return !Data_;
            }
        };
    }

    void XWrapper::Sync ()
    {
        XFlush (Display_);
        XSync (Display_, False);
    }

    QList<Window> XWrapper::GetWindows ()
    {
        ulong length = 0;
        Guarded<Window> data;

        QList<Window> result;
        if (GetRootWinProp (GetAtom ("_NET_CLIENT_LIST"), &length, data.GetAs<uchar**> ()))
            for (ulong i = 0; i < length; ++i)
                result << data [i];
        return result;
    }

    QString XWrapper::GetWindowTitle (Window wid)
    {
        QString name;

        ulong length = 0;
        Guarded<uchar> data;

        auto utf8Str = GetAtom ("UTF8_STRING");

        if (GetWinProp (wid, GetAtom ("_NET_WM_VISIBLE_NAME"), &length, data.Get (), utf8Str))
            name = QString::fromUtf8 (data.GetAs<char*> (false));

        if (name.isEmpty () && GetWinProp (wid, GetAtom ("_NET_WM_NAME"), &length, data.Get (), utf8Str))
            name = QString::fromUtf8 (data.GetAs<char*> (false));

        if (name.isEmpty () && GetWinProp (wid, GetAtom ("XA_WM_NAME"), &length, data.Get (), XA_STRING))
            name = QString::fromUtf8 (data.GetAs<char*> (false));

        if (name.isEmpty ())
        {
            XFetchName (Display_, wid, data.GetAs<char**> ());
            name = QString (data.GetAs<char*> (false));
        }

        if (name.isEmpty ())
        {
            XTextProperty prop;
            if (XGetWMName (Display_, wid, &prop))
            {
                name = QString::fromUtf8 (reinterpret_cast<char*> (prop.value));
                XFree (prop.value);
            }
        }

        return name;
    }

    QIcon XWrapper::GetWindowIcon (Window wid)
    {
        int fmt = 0;
        ulong type, count, extra;
        Guarded<ulong> data;

        XGetWindowProperty (Display_, wid, GetAtom ("_NET_WM_ICON"),
                0, std::numeric_limits<long>::max (), False, AnyPropertyType,
                &type, &fmt, &count, &extra,
                data.GetAs<uchar**> ());

        if (!data)
            return {};

        QIcon icon;

        auto cur = *data.Get (false);
        auto end = cur + count;
        while (cur < end)
        {
            QImage img (cur [0], cur [1], QImage::Format_ARGB32);
            cur += 2;
            const auto bytesCount = img.sizeInBytes ();
            for (int i = 0; i < bytesCount / 4; ++i, ++cur)
                reinterpret_cast<uint*> (img.bits ()) [i] = *cur;

            icon.addPixmap (QPixmap::fromImage (img));
        }

        return icon;
    }

    template<typename Flag>
    QFlags<Flag> XWrapper::GetFlagsList (Window wid, Atom property, const QHash<Atom, Flag>& atom2flag) const
    {
        QFlags<Flag> result;

        ulong length = 0;
        ulong *data = 0;
        if (!GetWinProp (wid, property, &length, reinterpret_cast<uchar**> (&data), XA_ATOM))
            return result;

        for (ulong i = 0; i < length; ++i)
            result |= atom2flag.value (data [i], static_cast<Flag> (0));

        XFree (data);

        return result;
    }

    WinStateFlags XWrapper::GetWindowState (Window wid)
    {
        auto get = [this] (const QByteArray& atom) { return GetAtom (AsStringView ("_NET_WM_STATE_" + atom)); };
        static const QHash<Atom, WinStateFlag> atom2flag
        {
            { get ("MODAL"), WinStateFlag::Modal },
            { get ("STICKY"), WinStateFlag::Sticky },
            { get ("MAXIMIZED_VERT"), WinStateFlag::MaximizedVert },
            { get ("MAXIMIZED_HORZ"), WinStateFlag::MaximizedHorz },
            { get ("SHADED"), WinStateFlag::Shaded },
            { get ("SKIP_TASKBAR"), WinStateFlag::SkipTaskbar },
            { get ("SKIP_PAGER"), WinStateFlag::SkipPager },
            { get ("HIDDEN"), WinStateFlag::Hidden },
            { get ("FULLSCREEN"), WinStateFlag::Fullscreen },
            { get ("ABOVE"), WinStateFlag::OnTop },
            { get ("BELOW"), WinStateFlag::OnBottom },
            { get ("DEMANDS_ATTENTION"), WinStateFlag::Attention },
        };

        return GetFlagsList (wid, GetAtom ("_NET_WM_STATE"), atom2flag);
    }

    AllowedActionFlags XWrapper::GetWindowActions (Window wid)
    {
        auto get = [this] (const QByteArray& atom) { return GetAtom (AsStringView ("_NET_WM_ACTION_" + atom)); };
        static const QHash<Atom, AllowedActionFlag> atom2flag
        {
            { get ("MOVE"), AllowedActionFlag::Move },
            { get ("RESIZE"), AllowedActionFlag::Resize },
            { get ("MINIMIZE"), AllowedActionFlag::Minimize },
            { get ("SHADE"), AllowedActionFlag::Shade },
            { get ("STICK"), AllowedActionFlag::Stick },
            { get ("MAXIMIZE_HORZ"), AllowedActionFlag::MaximizeHorz },
            { get ("MAXIMIZE_VERT"), AllowedActionFlag::MaximizeVert },
            { get ("FULLSCREEN"), AllowedActionFlag::ShowFullscreen },
            { get ("CHANGE_DESKTOP"), AllowedActionFlag::ChangeDesktop },
            { get ("CLOSE"), AllowedActionFlag::Close },
            { get ("ABOVE"), AllowedActionFlag::MoveToTop },
            { get ("BELOW"), AllowedActionFlag::MoveToBottom },
        };

        return GetFlagsList (wid, GetAtom ("_NET_WM_ALLOWED_ACTIONS"), atom2flag);
    }

    Window XWrapper::GetActiveApp ()
    {
        auto win = GetActiveWindow ();
        if (!win)
            return 0;

        Window transient = None;
        if (!ShouldShow (win) && XGetTransientForHint (Display_, win, &transient))
            return transient;

        return win;
    }

    bool XWrapper::IsLCWindow (Window wid)
    {
        ulong length = 0;
        Guarded<uchar> data;
        return GetWinProp (wid, GetAtom ("WM_CLASS"), &length, data.Get ()) &&
                QString (data.GetAs<char*> (false)).startsWith ("leechcraft"_ql);
    }

    bool XWrapper::ShouldShow (Window wid)
    {
        static const QList<Atom> ignoreAtoms
        {
            GetAtom ("_NET_WM_WINDOW_TYPE_DESKTOP"),
            GetAtom ("_NET_WM_WINDOW_TYPE_DOCK"),
            GetAtom ("_NET_WM_WINDOW_TYPE_TOOLBAR"),
            GetAtom ("_NET_WM_WINDOW_TYPE_UTILITY"),
            GetAtom ("_NET_WM_WINDOW_TYPE_MENU"),
            GetAtom ("_NET_WM_WINDOW_TYPE_SPLASH"),
            GetAtom ("_NET_WM_WINDOW_TYPE_POPUP_MENU")
        };

        for (const auto& type : GetWindowType (wid))
            if (ignoreAtoms.contains (type))
                return false;

        if (GetWindowState (wid) & WinStateFlag::SkipTaskbar)
            return false;

        Window transient = None;
        if (!XGetTransientForHint (Display_, wid, &transient))
            return true;

        if (transient == 0 || transient == wid || transient == AppWin_)
            return true;

        return !GetWindowType (transient).contains (GetAtom ("_NET_WM_WINDOW_TYPE_NORMAL"));
    }

    void XWrapper::Subscribe (Window wid)
    {
        if (IsLCWindow (wid))
            return;

        XSelectInput (Display_, wid, PropertyChangeMask);
    }

    void XWrapper::SetStrut (QWidget *widget, Qt::ToolBarArea area)
    {
        const auto wid = widget->effectiveWinId ();

        const auto& winGeom = widget->geometry ();

        switch (area)
        {
        case Qt::BottomToolBarArea:
            SetStrut (wid,
                    0, 0, 0, winGeom.height (),
                    0, 0,
                    0, 0,
                    0, 0,
                    winGeom.left (), winGeom.right ());
            break;
        case Qt::TopToolBarArea:
            SetStrut (wid,
                    0, 0, winGeom.height (), 0,
                    0, 0,
                    0, 0,
                    winGeom.left (), winGeom.right (),
                    0, 0);
            break;
        case Qt::LeftToolBarArea:
            SetStrut (wid,
                    winGeom.width (), 0, 0, 0,
                    winGeom.top (), winGeom.bottom (),
                    0, 0,
                    0, 0,
                    0, 0);
            break;
        case Qt::RightToolBarArea:
            SetStrut (wid,
                    0, winGeom.width (), 0, 0,
                    0, 0,
                    winGeom.top (), winGeom.bottom (),
                    0, 0,
                    0, 0);
            break;
        default:
            qWarning () << Q_FUNC_INFO
                    << "incorrect area passed"
                    << area;
            break;
        }
    }

    void XWrapper::ClearStrut (QWidget *w)
    {
        const auto wid = w->effectiveWinId ();
        XDeleteProperty (Display_, wid, GetAtom ("_NET_WM_STRUT"));
        XDeleteProperty (Display_, wid, GetAtom ("_NET_WM_STRUT_PARTIAL"));
    }

    void XWrapper::SetStrut (Window wid,
            ulong left, ulong right, ulong top, ulong bottom,
            ulong leftStartY, ulong leftEndY,
            ulong rightStartY, ulong rightEndY,
            ulong topStartX, ulong topEndX,
            ulong bottomStartX, ulong bottomEndX)
    {
        ulong struts [12] =
        {
            left,
            right,
            top,
            bottom,

            leftStartY,
            leftEndY,
            rightStartY,
            rightEndY,

            topStartX,
            topEndX,
            bottomStartX,
            bottomEndX
        };

        XChangeProperty (Display_, wid, GetAtom ("_NET_WM_STRUT_PARTIAL"),
                XA_CARDINAL, 32, PropModeReplace, reinterpret_cast<uchar*> (struts), 12);

        XChangeProperty (Display_, wid, GetAtom ("_NET_WM_STRUT"),
                XA_CARDINAL, 32, PropModeReplace, reinterpret_cast<uchar*> (struts), 4);
    }

    void XWrapper::RaiseWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("_NET_ACTIVE_WINDOW"), SourcePager);
    }

    void XWrapper::MinimizeWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("WM_CHANGE_STATE"), IconicState);
    }

    void XWrapper::MaximizeWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("_NET_WM_STATE"), StateAdd,
                GetAtom ("_NET_WM_STATE_MAXIMIZED_VERT"),
                GetAtom ("_NET_WM_STATE_MAXIMIZED_HORZ"),
                SourcePager);
    }

    void XWrapper::UnmaximizeWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("_NET_WM_STATE"), StateRemove,
                GetAtom ("_NET_WM_STATE_MAXIMIZED_VERT"),
                GetAtom ("_NET_WM_STATE_MAXIMIZED_HORZ"),
                SourcePager);
    }

    void XWrapper::ResizeWindow (Window wid, int width, int height)
    {
        XResizeWindow (Display_, wid, width, height);
    }

    void XWrapper::ShadeWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("_NET_WM_STATE"),
                StateAdd, GetAtom ("_NET_WM_STATE_SHADED"), 0, SourcePager);
    }

    void XWrapper::UnshadeWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("_NET_WM_STATE"),
                StateRemove, GetAtom ("_NET_WM_STATE_SHADED"), 0, SourcePager);
    }

    void XWrapper::MoveWindowTo (Window wid, Layer layer)
    {
        const auto top = layer == Layer::Top ? StateAdd : StateRemove;
        const auto bottom = layer == Layer::Bottom ? StateAdd : StateRemove;

        SendMessage (wid, GetAtom ("_NET_WM_STATE"), top,
                GetAtom ("_NET_WM_STATE_ABOVE"), 0, SourcePager);

        SendMessage (wid, GetAtom ("_NET_WM_STATE"), bottom,
                GetAtom ("_NET_WM_STATE_BELOW"), 0, SourcePager);
    }

    void XWrapper::CloseWindow (Window wid)
    {
        SendMessage (wid, GetAtom ("_NET_CLOSE_WINDOW"), 0, SourcePager);
    }

    template<typename T>
    void XWrapper::HandlePropNotify (T ev)
    {
        if (ev->state == XCB_PROPERTY_DELETE)
            return;

        const auto wid = ev->window;

        if (wid == AppWin_)
        {
            if (ev->atom == GetAtom ("_NET_CLIENT_LIST"))
                emit windowListChanged ();
            else if (ev->atom == GetAtom ("_NET_ACTIVE_WINDOW"))
                emit activeWindowChanged ();
            else if (ev->atom == GetAtom ("_NET_CURRENT_DESKTOP"))
                emit desktopChanged ();
        }
        else
        {
            if (ev->atom == GetAtom ("_NET_WM_VISIBLE_NAME") ||
                    ev->atom == GetAtom ("WM_NAME"))
                emit windowNameChanged (wid);
            else if (ev->atom == GetAtom ("_NET_WM_ICON"))
                emit windowIconChanged (wid);
            else if (ev->atom == GetAtom ("_NET_WM_DESKTOP"))
                emit windowDesktopChanged (wid);
            else if (ev->atom == GetAtom ("_NET_WM_STATE"))
                emit windowStateChanged (wid);
            else if (ev->atom == GetAtom ("_NET_WM_ALLOWED_ACTIONS"))
                emit windowActionsChanged (wid);
        }
    }

    Window XWrapper::GetActiveWindow ()
    {
        ulong length = 0;
        Guarded<ulong> data;

        if (!GetRootWinProp (GetAtom ("_NET_ACTIVE_WINDOW"), &length, data.GetAs<uchar**> (), XA_WINDOW))
            return 0;

        if (!length)
            return 0;

        return data [0];
    }

    int XWrapper::GetDesktopCount ()
    {
        ulong length = 0;
        Guarded<ulong> data;

        if (GetRootWinProp (GetAtom ("_NET_NUMBER_OF_DESKTOPS"), &length, data.GetAs<uchar**> (), XA_CARDINAL))
            return length > 0 ? data [0] : -1;

        return -1;
    }

    int XWrapper::GetCurrentDesktop ()
    {
        ulong length = 0;
        Guarded<ulong> data;

        if (GetRootWinProp (GetAtom ("_NET_CURRENT_DESKTOP"), &length, data.GetAs<uchar**> (), XA_CARDINAL))
            return length > 0 ? data [0] : -1;

        return -1;
    }

    void XWrapper::SetCurrentDesktop (int desktop)
    {
        SendMessage (AppWin_, GetAtom ("_NET_CURRENT_DESKTOP"), desktop);
    }

    QStringList XWrapper::GetDesktopNames ()
    {
        ulong length = 0;
        Guarded<uchar> data;

        if (!GetRootWinProp (GetAtom ("_NET_DESKTOP_NAMES"),
                &length, data.GetAs<uchar**> (), GetAtom ("UTF8_STRING")))
            return {};

        if (!data)
            return {};

        QStringList result;
        for (char *pos = data.GetAs<char*> (false), *end = data.GetAs<char*> (false) + length; pos < end; )
        {
            const auto& str = QString::fromUtf8 (pos);
            result << str;
            pos += str.toUtf8 ().size () + 1;
        }
        return result;
    }

    QString XWrapper::GetDesktopName (int desktop, const QString& def)
    {
        return GetDesktopNames ().value (desktop, def);
    }

    int XWrapper::GetWindowDesktop (Window wid)
    {
        ulong length = 0;
        Guarded<ulong> data;
        if (GetWinProp (wid, GetAtom ("_NET_WM_DESKTOP"), &length, data.GetAs<uchar**> (), XA_CARDINAL) && length)
            return data [0];

        if (GetWinProp (wid, GetAtom ("_WIN_WORKSPACE"), &length, data.GetAs<uchar**> (), XA_CARDINAL) && length)
            return data [0];

        return -1;
    }

    void XWrapper::MoveWindowToDesktop (Window wid, int num)
    {
        unsigned long data = num;
        XChangeProperty (Display_,
                    wid,
                    GetAtom ("_NET_WM_DESKTOP"),
                    XA_CARDINAL,
                    32,
                    PropModeReplace,
                    reinterpret_cast<unsigned char*> (&data),
                    1);
    }

    QRect XWrapper::GetAvailableGeometry (QScreen& screen)
    {
        auto available = screen.geometry ();
        const auto deskGeom = screen.virtualGeometry ();

        for (const auto wid : GetWindows ())
        {
            ulong length = 0;
            Guarded<ulong> struts;
            const auto status = GetWinProp (wid, GetAtom ("_NET_WM_STRUT_PARTIAL"),
                    &length, struts.GetAs<uchar**> (), XA_CARDINAL);
            if (!status || length != 12)
                continue;

            const QRect left
            {
                static_cast<int> (deskGeom.x ()),
                static_cast<int> (deskGeom.y () + struts [4]),
                static_cast<int> (struts [0]),
                static_cast<int> (struts [5] - struts [4])
            };
            if (available.intersects (left))
                available.setX (left.width ());

            const QRect right
            {
                static_cast<int> (deskGeom.x () + deskGeom.width () - struts [1]),
                static_cast<int> (deskGeom.y () + struts [6]),
                static_cast<int> (struts [1]),
                static_cast<int> (struts [7] - struts [6])
            };
            if (available.intersects (right))
                available.setWidth (right.x () - available.x ());

            const QRect top
            {
                static_cast<int> (deskGeom.x () + struts [8]),
                static_cast<int> (deskGeom.y ()),
                static_cast<int> (struts [9] - struts [8]),
                static_cast<int> (struts [2])
            };
            if (available.intersects (top))
                available.setY (top.height ());

            const QRect bottom
            {
                static_cast<int> (deskGeom.x () + struts [10]),
                static_cast<int> (deskGeom.y () + deskGeom.height () - struts [3]),
                static_cast<int> (struts [11] - struts [10]),
                static_cast<int> (struts [3])
            };
            if (available.intersects (bottom))
                available.setHeight (bottom.y () - available.y ());
        }

        return available;
    }

    QRect XWrapper::GetAvailableGeometry (QWidget *widget)
    {
        return GetAvailableGeometry (*widget->screen ());
    }

    Atom XWrapper::GetAtom (std::string_view name)
    {
        const auto pos = Atoms_.find (AsByteArray (name));
        if (pos != Atoms_.end ())
            return *pos;

        auto atom = XInternAtom (Display_, name.data (), false);
        Atoms_ [ToByteArray (name)] = atom;
        return atom;
    }

    bool XWrapper::GetWinProp (Window win, Atom property,
            ulong *length, unsigned char **result, Atom req) const
    {
        int fmt = 0;
        ulong type = 0, rest = 0;
        return XGetWindowProperty (Display_, win,
                property, 0, 1024, false, req, &type,
                &fmt, length, &rest, result) == Success;
    }

    bool XWrapper::GetRootWinProp (Atom property,
            ulong *length, uchar **result, Atom req) const
    {
        return GetWinProp (AppWin_, property, length, result, req);
    }

    QList<Atom> XWrapper::GetWindowType (Window wid)
    {
        QList<Atom> result;

        ulong length = 0;
        ulong *data = nullptr;

        if (!GetWinProp (wid, GetAtom ("_NET_WM_WINDOW_TYPE"),
                &length, reinterpret_cast<uchar**> (&data)))
            return result;

        for (ulong i = 0; i < length; ++i)
            result << data [i];

        XFree (data);
        return result;
    }

    bool XWrapper::SendMessage (Window wid, Atom atom, ulong d0, ulong d1, ulong d2, ulong d3, ulong d4)
    {
        XEvent msg;
        msg.xclient.window = wid;
        msg.xclient.type = ClientMessage;
        msg.xclient.message_type = atom;
        msg.xclient.send_event = true;
        msg.xclient.display = Display_;
        msg.xclient.format = 32;
        msg.xclient.data.l [0] = d0;
        msg.xclient.data.l [1] = d1;
        msg.xclient.data.l [2] = d2;
        msg.xclient.data.l [3] = d3;
        msg.xclient.data.l [4] = d4;

        auto flags = SubstructureRedirectMask | SubstructureNotifyMask;
        return XSendEvent (Display_, AppWin_, false, flags, &msg) == Success;
    }

    void XWrapper::initialize ()
    {
    }
}