JUCE/modules/juce_gui_basics/native/x11/juce_linux_XWindowSystem.cpp

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.

   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

#if JUCE_DEBUG && ! defined (JUCE_DEBUG_XERRORS)
 #define JUCE_DEBUG_XERRORS 1

 #if ! defined (JUCE_DEBUG_XERRORS_SYNCHRONOUSLY)
  #define JUCE_DEBUG_XERRORS_SYNCHRONOUSLY 0
 #endif
#endif

#if JUCE_MODULE_AVAILABLE_juce_gui_extra
 #define JUCE_X11_SUPPORTS_XEMBED 1
#else
 #define JUCE_X11_SUPPORTS_XEMBED 0
#endif

namespace
{
    struct XFreeDeleter
    {
        void operator() (void* ptr) const
        {
            if (ptr != nullptr)
                X11Symbols::getInstance()->xFree (ptr);
        }
    };

    template <typename Data>
    std::unique_ptr<Data, XFreeDeleter> makeXFreePtr (Data* raw) { return std::unique_ptr<Data, XFreeDeleter> (raw); }

    template <typename Data, typename Deleter>
    std::unique_ptr<Data, Deleter> makeDeletedPtr (Data* raw, const Deleter& d) { return std::unique_ptr<Data, Deleter> (raw, d); }

    template <typename XValueType>
    struct XValueHolder
    {
        XValueHolder (XValueType&& xv, const std::function<void(XValueType&)>& cleanup)
            : value (std::move (xv)), cleanupFunc (cleanup)
        {}

        ~XValueHolder()
        {
            cleanupFunc (value);
        }

        XValueType value;
        std::function<void(XValueType&)> cleanupFunc;
    };
}

//==============================================================================
XWindowSystemUtilities::ScopedXLock::ScopedXLock()
{
    if (auto* xWindow = XWindowSystem::getInstanceWithoutCreating())
        if (auto* d = xWindow->getDisplay())
            X11Symbols::getInstance()->xLockDisplay (d);
}

XWindowSystemUtilities::ScopedXLock::~ScopedXLock()
{
    if (auto* xWindow = XWindowSystem::getInstanceWithoutCreating())
        if (auto* d = xWindow->getDisplay())
            X11Symbols::getInstance()->xUnlockDisplay (d);
}

//==============================================================================
XWindowSystemUtilities::Atoms::Atoms (::Display* display)
{
    protocols                    = getIfExists (display, "WM_PROTOCOLS");
    protocolList [TAKE_FOCUS]    = getIfExists (display, "WM_TAKE_FOCUS");
    protocolList [DELETE_WINDOW] = getIfExists (display, "WM_DELETE_WINDOW");
    protocolList [PING]          = getIfExists (display, "_NET_WM_PING");
    changeState                  = getIfExists (display, "WM_CHANGE_STATE");
    state                        = getIfExists (display, "WM_STATE");
    userTime                     = getCreating (display, "_NET_WM_USER_TIME");
    activeWin                    = getCreating (display, "_NET_ACTIVE_WINDOW");
    pid                          = getCreating (display, "_NET_WM_PID");
    windowType                   = getIfExists (display, "_NET_WM_WINDOW_TYPE");
    windowState                  = getIfExists (display, "_NET_WM_STATE");
    windowStateHidden            = getIfExists (display, "_NET_WM_STATE_HIDDEN");

    XdndAware                    = getCreating (display, "XdndAware");
    XdndEnter                    = getCreating (display, "XdndEnter");
    XdndLeave                    = getCreating (display, "XdndLeave");
    XdndPosition                 = getCreating (display, "XdndPosition");
    XdndStatus                   = getCreating (display, "XdndStatus");
    XdndDrop                     = getCreating (display, "XdndDrop");
    XdndFinished                 = getCreating (display, "XdndFinished");
    XdndSelection                = getCreating (display, "XdndSelection");

    XdndTypeList                 = getCreating (display, "XdndTypeList");
    XdndActionList               = getCreating (display, "XdndActionList");
    XdndActionCopy               = getCreating (display, "XdndActionCopy");
    XdndActionPrivate            = getCreating (display, "XdndActionPrivate");
    XdndActionDescription        = getCreating (display, "XdndActionDescription");

    XembedMsgType                = getCreating (display, "_XEMBED");
    XembedInfo                   = getCreating (display, "_XEMBED_INFO");

    allowedMimeTypes[0]          = getCreating (display, "UTF8_STRING");
    allowedMimeTypes[1]          = getCreating (display, "text/plain;charset=utf-8");
    allowedMimeTypes[2]          = getCreating (display, "text/plain");
    allowedMimeTypes[3]          = getCreating (display, "text/uri-list");

    allowedActions[0]            = getCreating (display, "XdndActionMove");
    allowedActions[1]            = XdndActionCopy;
    allowedActions[2]            = getCreating (display, "XdndActionLink");
    allowedActions[3]            = getCreating (display, "XdndActionAsk");
    allowedActions[4]            = XdndActionPrivate;

    utf8String                   = getCreating (display, "UTF8_STRING");
    clipboard                    = getCreating (display, "CLIPBOARD");
    targets                      = getCreating (display, "TARGETS");
}

Atom XWindowSystemUtilities::Atoms::getIfExists (::Display* display, const char* name)
{
    return X11Symbols::getInstance()->xInternAtom (display, name, True);
}

Atom XWindowSystemUtilities::Atoms::getCreating (::Display* display, const char* name)
{
    return X11Symbols::getInstance()->xInternAtom (display, name, False);
}

String XWindowSystemUtilities::Atoms::getName (::Display* display, Atom atom)
{
    if (atom == None)
        return "None";

    return makeXFreePtr (X11Symbols::getInstance()->xGetAtomName (display, atom)).get();
}

bool XWindowSystemUtilities::Atoms::isMimeTypeFile (::Display* display, Atom atom)
{
    return getName (display, atom).equalsIgnoreCase ("text/uri-list");
}

//==============================================================================
XWindowSystemUtilities::GetXProperty::GetXProperty (::Display* display, Window window, Atom atom,
                                                    long offset, long length, bool shouldDelete, Atom requestedType)
{
    success = (X11Symbols::getInstance()->xGetWindowProperty (display, window, atom, offset, length,
                                                              (Bool) shouldDelete, requestedType, &actualType,
                                                              &actualFormat, &numItems, &bytesLeft, &data) == Success)
                && data != nullptr;
}

XWindowSystemUtilities::GetXProperty::~GetXProperty()
{
    if (data != nullptr)
        X11Symbols::getInstance()->xFree (data);
}

//==============================================================================
std::unique_ptr<XWindowSystemUtilities::XSettings> XWindowSystemUtilities::XSettings::createXSettings (::Display* d)
{
    const auto settingsAtom = Atoms::getCreating (d, "_XSETTINGS_SETTINGS");
    const auto settingsWindow = X11Symbols::getInstance()->xGetSelectionOwner (d,
                                                                               Atoms::getCreating (d, "_XSETTINGS_S0"));

    if (settingsWindow == None)
        return {};

    return rawToUniquePtr (new XWindowSystemUtilities::XSettings (d, settingsWindow, settingsAtom));
}

XWindowSystemUtilities::XSettings::XSettings (::Display* d, ::Window settingsWindowIn, Atom settingsAtomIn)
    : display (d), settingsWindow (settingsWindowIn), settingsAtom (settingsAtomIn)
{
    update();
}

XWindowSystemUtilities::XSetting XWindowSystemUtilities::XSettings::getSetting (const String& name) const
{
    const auto iter = settings.find (name);

    if (iter != settings.end())
        return iter->second;

    return {};
}

void XWindowSystemUtilities::XSettings::update()
{
    const GetXProperty prop { display,
                              settingsWindow,
                              settingsAtom,
                              0L,
                              std::numeric_limits<long>::max(),
                              false,
                              settingsAtom };

    if (prop.success
        && prop.actualType == settingsAtom
        && prop.actualFormat == 8
        && prop.numItems > 0)
    {
        const auto bytes = (size_t) prop.numItems;
        auto* data = prop.data;
        size_t byteNum = 0;

        const auto increment = [&] (size_t amount)
        {
            data    += amount;
            byteNum += amount;
        };

        struct Header
        {
            CARD8 byteOrder;
            CARD8 padding[3];
            CARD32 serial;
            CARD32 nSettings;
        };

        const auto* header = unalignedPointerCast<const Header*> (data);
        const auto headerSerial = (int) header->serial;
        increment (sizeof (Header));

        const auto readCARD16 = [&]() -> CARD16
        {
            if (byteNum + sizeof (CARD16) > bytes)
                return {};

            const auto value = header->byteOrder == MSBFirst ? ByteOrder::bigEndianShort (data)
                                                             : ByteOrder::littleEndianShort (data);
            increment (sizeof (CARD16));
            return value;
        };

        const auto readCARD32 = [&]() -> CARD32
        {
            if (byteNum + sizeof (CARD32) > bytes)
                return {};

            const auto value = header->byteOrder == MSBFirst ? ByteOrder::bigEndianInt (data)
                                                             : ByteOrder::littleEndianInt (data);
            increment (sizeof (CARD32));
            return value;
        };

        const auto readString = [&] (size_t nameLen) -> String
        {
            const auto padded = (nameLen + 3) & (~(size_t) 3);

            if (byteNum + padded > bytes)
                return {};

            auto* ptr = reinterpret_cast<const char*> (data);
            const String result (ptr, nameLen);
            increment (padded);
            return result;
        };

        CARD16 setting = 0;

        while (byteNum < bytes && setting < header->nSettings)
        {
            const auto type = *reinterpret_cast<const char*> (data);
            increment (2);

            const auto name   = readString (readCARD16());
            const auto serial = (int) readCARD32();

            enum { XSettingsTypeInteger, XSettingsTypeString, XSettingsTypeColor };

            const auto parsedSetting = [&]() -> XSetting
            {
                switch (type)
                {
                    case XSettingsTypeInteger:
                        return { name, (int) readCARD32() };

                    case XSettingsTypeString:
                        return { name, readString (readCARD32()) };

                    case XSettingsTypeColor:
                        // Order is important, these should be kept as separate statements!
                        const auto r = (uint8) readCARD16();
                        const auto g = (uint8) readCARD16();
                        const auto b = (uint8) readCARD16();
                        const auto a = (uint8) readCARD16();
                        return { name, Colour { r, g, b, a } };
                }

                return {};
            }();

            if (serial > lastUpdateSerial)
            {
                settings[parsedSetting.name] = parsedSetting;
                listeners.call ([&parsedSetting] (Listener& l) { l.settingChanged (parsedSetting); });
            }

            setting += 1;
        }

        lastUpdateSerial = headerSerial;
    }
}

//==============================================================================
::Window juce_messageWindowHandle;
XContext windowHandleXContext;

#if JUCE_X11_SUPPORTS_XEMBED
 bool juce_handleXEmbedEvent (ComponentPeer*, void*);
 unsigned long juce_getCurrentFocusWindow (ComponentPeer*);
#endif

struct MotifWmHints
{
    unsigned long flags       = 0;
    unsigned long functions   = 0;
    unsigned long decorations = 0;
    long          input_mode  = 0;
    unsigned long status      = 0;
};

//=============================== X11 - Error Handling =========================
namespace X11ErrorHandling
{
    static XErrorHandler   oldErrorHandler   = {};
    static XIOErrorHandler oldIOErrorHandler = {};

    // Usually happens when client-server connection is broken
    static int ioErrorHandler (::Display*)
    {
        DBG ("ERROR: connection to X server broken.. terminating.");

        if (JUCEApplicationBase::isStandaloneApp())
            MessageManager::getInstance()->stopDispatchLoop();

        return 0;
    }

    static int errorHandler (::Display* display, XErrorEvent* event)
    {
        ignoreUnused (display, event);

       #if JUCE_DEBUG_XERRORS
        char errorStr[64]   = { 0 };
        char requestStr[64] = { 0 };

        X11Symbols::getInstance()->xGetErrorText (display, event->error_code, errorStr, 64);
        X11Symbols::getInstance()->xGetErrorDatabaseText (display, "XRequest", String (event->request_code).toUTF8(), "Unknown", requestStr, 64);

        DBG ("ERROR: X returned " << errorStr << " for operation " << requestStr);
       #endif

        return 0;
    }

    static void installXErrorHandlers()
    {
        oldIOErrorHandler = X11Symbols::getInstance()->xSetIOErrorHandler (ioErrorHandler);
        oldErrorHandler   = X11Symbols::getInstance()->xSetErrorHandler   (errorHandler);
    }

    static void removeXErrorHandlers()
    {
        X11Symbols::getInstance()->xSetIOErrorHandler (oldIOErrorHandler);
        oldIOErrorHandler = {};

        X11Symbols::getInstance()->xSetErrorHandler (oldErrorHandler);
        oldErrorHandler = {};
    }
}

//=============================== X11 - Keys ===================================
namespace Keys
{
    enum MouseButtons
    {
        NoButton = 0,
        LeftButton = 1,
        MiddleButton = 2,
        RightButton = 3,
        WheelUp = 4,
        WheelDown = 5
    };

    static int AltMask = 0;
    static int NumLockMask = 0;
    static bool numLock = false;
    static bool capsLock = false;
    static char keyStates [32];
    static constexpr int extendedKeyModifier = 0x10000000;
    static bool modifierKeysAreStale = false;

    static void refreshStaleModifierKeys()
    {
        if (modifierKeysAreStale)
        {
            XWindowSystem::getInstance()->getNativeRealtimeModifiers();
            modifierKeysAreStale = false;
        }
    }

    // Call this function when only the mouse keys need to be refreshed e.g. when the event
    // parameter already has information about the keys.
    static void refreshStaleMouseKeys()
    {
        if (modifierKeysAreStale)
        {
            const auto oldMods = ModifierKeys::currentModifiers;
            XWindowSystem::getInstance()->getNativeRealtimeModifiers();
            ModifierKeys::currentModifiers = oldMods.withoutMouseButtons()
                                                    .withFlags (ModifierKeys::currentModifiers.withOnlyMouseButtons()
                                                                                              .getRawFlags());
            modifierKeysAreStale = false;
        }
    }
}

const int KeyPress::spaceKey              = XK_space         & 0xff;
const int KeyPress::returnKey             = XK_Return        & 0xff;
const int KeyPress::escapeKey             = XK_Escape        & 0xff;
const int KeyPress::backspaceKey          = XK_BackSpace     & 0xff;
const int KeyPress::leftKey               = (XK_Left         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::rightKey              = (XK_Right        & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::upKey                 = (XK_Up           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::downKey               = (XK_Down         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::pageUpKey             = (XK_Page_Up      & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::pageDownKey           = (XK_Page_Down    & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::endKey                = (XK_End          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::homeKey               = (XK_Home         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::insertKey             = (XK_Insert       & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::deleteKey             = (XK_Delete       & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::tabKey                = XK_Tab           & 0xff;
const int KeyPress::F1Key                 = (XK_F1           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F2Key                 = (XK_F2           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F3Key                 = (XK_F3           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F4Key                 = (XK_F4           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F5Key                 = (XK_F5           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F6Key                 = (XK_F6           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F7Key                 = (XK_F7           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F8Key                 = (XK_F8           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F9Key                 = (XK_F9           & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F10Key                = (XK_F10          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F11Key                = (XK_F11          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F12Key                = (XK_F12          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F13Key                = (XK_F13          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F14Key                = (XK_F14          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F15Key                = (XK_F15          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F16Key                = (XK_F16          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F17Key                = (XK_F17          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F18Key                = (XK_F18          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F19Key                = (XK_F19          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F20Key                = (XK_F20          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F21Key                = (XK_F21          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F22Key                = (XK_F22          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F23Key                = (XK_F23          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F24Key                = (XK_F24          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F25Key                = (XK_F25          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F26Key                = (XK_F26          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F27Key                = (XK_F27          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F28Key                = (XK_F28          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F29Key                = (XK_F29          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F30Key                = (XK_F30          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F31Key                = (XK_F31          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F32Key                = (XK_F32          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F33Key                = (XK_F33          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F34Key                = (XK_F34          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::F35Key                = (XK_F35          & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad0            = (XK_KP_0         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad1            = (XK_KP_1         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad2            = (XK_KP_2         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad3            = (XK_KP_3         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad4            = (XK_KP_4         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad5            = (XK_KP_5         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad6            = (XK_KP_6         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad7            = (XK_KP_7         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad8            = (XK_KP_8         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPad9            = (XK_KP_9         & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadAdd          = (XK_KP_Add       & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadSubtract     = (XK_KP_Subtract  & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadMultiply     = (XK_KP_Multiply  & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadDivide       = (XK_KP_Divide    & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadSeparator    = (XK_KP_Separator & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadDecimalPoint = (XK_KP_Decimal   & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadEquals       = (XK_KP_Equal     & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::numberPadDelete       = (XK_KP_Delete    & 0xff) | Keys::extendedKeyModifier;
const int KeyPress::playKey               = ((int) 0xffeeff00)       | Keys::extendedKeyModifier;
const int KeyPress::stopKey               = ((int) 0xffeeff01)       | Keys::extendedKeyModifier;
const int KeyPress::fastForwardKey        = ((int) 0xffeeff02)       | Keys::extendedKeyModifier;
const int KeyPress::rewindKey             = ((int) 0xffeeff03)       | Keys::extendedKeyModifier;

static void updateKeyStates (int keycode, bool press) noexcept
{
    auto keybyte = keycode >> 3;
    auto keybit = (1 << (keycode & 7));

    if (press)
        Keys::keyStates [keybyte] |= keybit;
    else
        Keys::keyStates [keybyte] &= ~keybit;
}

static void updateKeyModifiers (int status) noexcept
{
    int keyMods = 0;

    if ((status & ShiftMask)     != 0) keyMods |= ModifierKeys::shiftModifier;
    if ((status & ControlMask)   != 0) keyMods |= ModifierKeys::ctrlModifier;
    if ((status & Keys::AltMask) != 0) keyMods |= ModifierKeys::altModifier;

    ModifierKeys::currentModifiers = ModifierKeys::currentModifiers.withOnlyMouseButtons().withFlags (keyMods);

    Keys::numLock  = ((status & Keys::NumLockMask) != 0);
    Keys::capsLock = ((status & LockMask)          != 0);
}

static bool updateKeyModifiersFromSym (KeySym sym, bool press) noexcept
{
    int modifier = 0;
    bool isModifier = true;

    switch (sym)
    {
        case XK_Shift_L:
        case XK_Shift_R:   modifier = ModifierKeys::shiftModifier; break;

        case XK_Control_L:
        case XK_Control_R: modifier = ModifierKeys::ctrlModifier; break;

        case XK_Alt_L:
        case XK_Alt_R:     modifier = ModifierKeys::altModifier; break;

        case XK_Num_Lock:
            if (press)
                Keys::numLock = ! Keys::numLock;

            break;

        case XK_Caps_Lock:
            if (press)
                Keys::capsLock = ! Keys::capsLock;

            break;

        case XK_Scroll_Lock:
            break;

        default:
            isModifier = false;
            break;
    }

    ModifierKeys::currentModifiers = press ? ModifierKeys::currentModifiers.withFlags (modifier)
                                           : ModifierKeys::currentModifiers.withoutFlags (modifier);

    return isModifier;
}

enum
{
    KeyPressEventType = 2
};

//================================== X11 - Shm =================================
#if JUCE_USE_XSHM
 namespace XSHMHelpers
 {
     static int trappedErrorCode = 0;

     extern "C" int errorTrapHandler (Display*, XErrorEvent* err);
     extern "C" int errorTrapHandler (Display*, XErrorEvent* err)
     {
         trappedErrorCode = err->error_code;
         return 0;
     }

     static bool isShmAvailable (::Display* display)
     {
         static bool isChecked = false;
         static bool isAvailable = false;

         if (! isChecked)
         {
             isChecked = true;

             if (display != nullptr)
             {
                 int major, minor;
                 Bool pixmaps;

                 XWindowSystemUtilities::ScopedXLock xLock;

                 if (X11Symbols::getInstance()->xShmQueryVersion (display, &major, &minor, &pixmaps))
                 {
                     trappedErrorCode = 0;
                     auto oldHandler = X11Symbols::getInstance()->xSetErrorHandler (errorTrapHandler);

                     XShmSegmentInfo segmentInfo;
                     zerostruct (segmentInfo);

                     if (auto* xImage = X11Symbols::getInstance()->xShmCreateImage (display,
                                                                                    X11Symbols::getInstance()->xDefaultVisual (display, X11Symbols::getInstance()->xDefaultScreen (display)),
                                                                                    24, ZPixmap, nullptr, &segmentInfo, 50, 50))
                     {
                         if ((segmentInfo.shmid = shmget (IPC_PRIVATE,
                                                          (size_t) (xImage->bytes_per_line * xImage->height),
                                                          IPC_CREAT | 0777)) >= 0)
                         {
                             segmentInfo.shmaddr = (char*) shmat (segmentInfo.shmid, nullptr, 0);

                             if (segmentInfo.shmaddr != (void*) -1)
                             {
                                 segmentInfo.readOnly = False;
                                 xImage->data = segmentInfo.shmaddr;
                                 X11Symbols::getInstance()->xSync (display, False);

                                 if (X11Symbols::getInstance()->xShmAttach (display, &segmentInfo) != 0)
                                 {
                                     X11Symbols::getInstance()->xSync (display, False);
                                     X11Symbols::getInstance()->xShmDetach (display, &segmentInfo);

                                     isAvailable = true;
                                 }
                             }

                             X11Symbols::getInstance()->xFlush (display);
                             X11Symbols::getInstance()->xDestroyImage (xImage);

                             shmdt (segmentInfo.shmaddr);
                         }

                         shmctl (segmentInfo.shmid, IPC_RMID, nullptr);

                         X11Symbols::getInstance()->xSetErrorHandler (oldHandler);

                         if (trappedErrorCode != 0)
                             isAvailable = false;
                     }
                 }
             }
         }

         return isAvailable;
     }
 }
#endif

//=============================== X11 - Render =================================
#if JUCE_USE_XRENDER
 namespace XRender
 {
     static bool isAvailable (::Display* display)
     {
         int major, minor;
         return X11Symbols::getInstance()->xRenderQueryVersion (display, &major, &minor);
     }

     static bool hasCompositingWindowManager (::Display* display)
     {
         return display != nullptr
                 && X11Symbols::getInstance()->xGetSelectionOwner (display,
                                                                   XWindowSystemUtilities::Atoms::getCreating (display, "_NET_WM_CM_S0")) != 0;
     }

     static XRenderPictFormat* findPictureFormat (::Display* display)
     {
         XWindowSystemUtilities::ScopedXLock xLock;

         if (isAvailable (display))
         {
             if (auto* pictFormat = X11Symbols::getInstance()->xRenderFindStandardFormat (display, PictStandardARGB32))
             {
                 XRenderPictFormat desiredFormat;
                 desiredFormat.type = PictTypeDirect;
                 desiredFormat.depth = 32;

                 desiredFormat.direct.alphaMask = 0xff;
                 desiredFormat.direct.redMask   = 0xff;
                 desiredFormat.direct.greenMask = 0xff;
                 desiredFormat.direct.blueMask  = 0xff;

                 desiredFormat.direct.alpha = 24;
                 desiredFormat.direct.red   = 16;
                 desiredFormat.direct.green = 8;
                 desiredFormat.direct.blue  = 0;

                 pictFormat = X11Symbols::getInstance()->xRenderFindFormat (display,
                                                                            PictFormatType | PictFormatDepth
                                                                             | PictFormatRedMask | PictFormatRed
                                                                             | PictFormatGreenMask | PictFormatGreen
                                                                             | PictFormatBlueMask | PictFormatBlue
                                                                             | PictFormatAlphaMask | PictFormatAlpha,
                                                                            &desiredFormat,
                                                                            0);

                 return pictFormat;
             }
         }

         return nullptr;
     }
 }
#endif

//================================ X11 - Visuals ===============================
namespace Visuals
{
    static Visual* findVisualWithDepth (::Display* display, int desiredDepth)
    {
        XWindowSystemUtilities::ScopedXLock xLock;

        Visual* visual = nullptr;
        int numVisuals = 0;
        auto desiredMask = VisualNoMask;
        XVisualInfo desiredVisual;

        desiredVisual.screen = X11Symbols::getInstance()->xDefaultScreen (display);
        desiredVisual.depth = desiredDepth;

        desiredMask = VisualScreenMask | VisualDepthMask;

        if (desiredDepth == 32)
        {
            desiredVisual.c_class    = TrueColor;
            desiredVisual.red_mask   = 0x00FF0000;
            desiredVisual.green_mask = 0x0000FF00;
            desiredVisual.blue_mask  = 0x000000FF;
            desiredVisual.bits_per_rgb = 8;

            desiredMask |= VisualClassMask;
            desiredMask |= VisualRedMaskMask;
            desiredMask |= VisualGreenMaskMask;
            desiredMask |= VisualBlueMaskMask;
            desiredMask |= VisualBitsPerRGBMask;
        }

        if (auto xvinfos = makeXFreePtr (X11Symbols::getInstance()->xGetVisualInfo (display, desiredMask, &desiredVisual, &numVisuals)))
        {
            for (int i = 0; i < numVisuals; i++)
            {
                if (xvinfos.get()[i].depth == desiredDepth)
                {
                    visual = xvinfos.get()[i].visual;
                    break;
                }
            }
        }

        return visual;
    }

    static Visual* findVisualFormat (::Display* display, int desiredDepth, int& matchedDepth)
    {
        Visual* visual = nullptr;

        if (desiredDepth == 32)
        {
           #if JUCE_USE_XSHM
            if (XSHMHelpers::isShmAvailable (display))
            {
               #if JUCE_USE_XRENDER
                if (XRender::isAvailable (display))
                {
                    if (XRender::findPictureFormat (display) != nullptr)
                    {
                        int numVisuals = 0;
                        XVisualInfo desiredVisual;
                        desiredVisual.screen = X11Symbols::getInstance()->xDefaultScreen (display);
                        desiredVisual.depth = 32;
                        desiredVisual.bits_per_rgb = 8;

                        if (auto xvinfos = makeXFreePtr (X11Symbols::getInstance()->xGetVisualInfo (display,
                                                                                                    VisualScreenMask | VisualDepthMask | VisualBitsPerRGBMask,
                                                                                                    &desiredVisual, &numVisuals)))
                        {
                            for (int i = 0; i < numVisuals; ++i)
                            {
                                auto pictVisualFormat = X11Symbols::getInstance()->xRenderFindVisualFormat (display, xvinfos.get()[i].visual);

                                if (pictVisualFormat != nullptr
                                     && pictVisualFormat->type == PictTypeDirect
                                     && pictVisualFormat->direct.alphaMask)
                                {
                                    visual = xvinfos.get()[i].visual;
                                    matchedDepth = 32;
                                    break;
                                }
                            }
                        }
                    }
                }
               #endif
                if (visual == nullptr)
                {
                    visual = findVisualWithDepth (display, 32);

                    if (visual != nullptr)
                        matchedDepth = 32;
                }
            }
           #endif
        }

        if (visual == nullptr && desiredDepth >= 24)
        {
            visual = findVisualWithDepth (display, 24);

            if (visual != nullptr)
                matchedDepth = 24;
        }

        if (visual == nullptr && desiredDepth >= 16)
        {
            visual = findVisualWithDepth (display, 16);

            if (visual != nullptr)
                matchedDepth = 16;
        }

        return visual;
    }
}

//================================= X11 - Bitmap ===============================
class XBitmapImage  : public ImagePixelData
{
public:
    explicit XBitmapImage (XImage* image)
        : ImagePixelData (image->depth == 24 ? Image::RGB : Image::ARGB, image->width, image->height),
          xImage (image),
          imageDepth ((unsigned int) xImage->depth)
    {
        pixelStride = xImage->bits_per_pixel / 8;
        lineStride = xImage->bytes_per_line;
        imageData = reinterpret_cast<uint8*> (xImage->data);
    }

    XBitmapImage (Image::PixelFormat format, int w, int h,
                  bool clearImage, unsigned int imageDepth_, Visual* visual)
        : ImagePixelData (format, w, h),
          imageDepth (imageDepth_)
    {
        jassert (format == Image::RGB || format == Image::ARGB);

        pixelStride = (format == Image::RGB) ? 3 : 4;
        lineStride = ((w * pixelStride + 3) & ~3);

        XWindowSystemUtilities::ScopedXLock xLock;

       #if JUCE_USE_XSHM
        usingXShm = false;

        if ((imageDepth > 16) && XSHMHelpers::isShmAvailable (display))
        {
            zerostruct (segmentInfo);

            segmentInfo.shmid = -1;
            segmentInfo.shmaddr = (char *) -1;
            segmentInfo.readOnly = False;

            xImage.reset (X11Symbols::getInstance()->xShmCreateImage (display, visual, imageDepth, ZPixmap, nullptr,
                                                                      &segmentInfo, (unsigned int) w, (unsigned int) h));

            if (xImage != nullptr)
            {
                if ((segmentInfo.shmid = shmget (IPC_PRIVATE,
                                                 (size_t) (xImage->bytes_per_line * xImage->height),
                                                 IPC_CREAT | 0777)) >= 0)
                {
                    if (segmentInfo.shmid != -1)
                    {
                        segmentInfo.shmaddr = (char*) shmat (segmentInfo.shmid, nullptr, 0);

                        if (segmentInfo.shmaddr != (void*) -1)
                        {
                            segmentInfo.readOnly = False;

                            xImage->data = segmentInfo.shmaddr;
                            imageData = (uint8*) segmentInfo.shmaddr;

                            if (X11Symbols::getInstance()->xShmAttach (display, &segmentInfo) != 0)
                                usingXShm = true;
                            else
                                jassertfalse;
                        }
                        else
                        {
                            shmctl (segmentInfo.shmid, IPC_RMID, nullptr);
                        }
                    }
                }
            }
        }

        if (! isUsingXShm())
       #endif
        {
            imageDataAllocated.allocate ((size_t) (lineStride * h), format == Image::ARGB && clearImage);
            imageData = imageDataAllocated;

            xImage.reset ((XImage*) ::calloc (1, sizeof (XImage)));

            xImage->width = w;
            xImage->height = h;
            xImage->xoffset = 0;
            xImage->format = ZPixmap;
            xImage->data = (char*) imageData;
            xImage->byte_order = X11Symbols::getInstance()->xImageByteOrder (display);
            xImage->bitmap_unit = X11Symbols::getInstance()->xBitmapUnit (display);
            xImage->bitmap_bit_order = X11Symbols::getInstance()->xBitmapBitOrder (display);
            xImage->bitmap_pad = 32;
            xImage->depth = pixelStride * 8;
            xImage->bytes_per_line = lineStride;
            xImage->bits_per_pixel = pixelStride * 8;
            xImage->red_mask   = 0x00FF0000;
            xImage->green_mask = 0x0000FF00;
            xImage->blue_mask  = 0x000000FF;

            if (imageDepth == 16)
            {
                int pixStride = 2;
                auto stride = ((w * pixStride + 3) & ~3);

                imageData16Bit.malloc (stride * h);
                xImage->data = imageData16Bit;
                xImage->bitmap_pad = 16;
                xImage->depth = pixStride * 8;
                xImage->bytes_per_line = stride;
                xImage->bits_per_pixel = pixStride * 8;
                xImage->red_mask   = visual->red_mask;
                xImage->green_mask = visual->green_mask;
                xImage->blue_mask  = visual->blue_mask;
            }

            if (! X11Symbols::getInstance()->xInitImage (xImage.get()))
                jassertfalse;
        }
    }

    ~XBitmapImage() override
    {
        XWindowSystemUtilities::ScopedXLock xLock;

        if (gc != None)
            X11Symbols::getInstance()->xFreeGC (display, gc);

       #if JUCE_USE_XSHM
        if (isUsingXShm())
        {
            X11Symbols::getInstance()->xShmDetach (display, &segmentInfo);

            X11Symbols::getInstance()->xFlush (display);

            shmdt (segmentInfo.shmaddr);
            shmctl (segmentInfo.shmid, IPC_RMID, nullptr);
        }
        else
       #endif
        {
            xImage->data = nullptr;
        }
    }

    std::unique_ptr<LowLevelGraphicsContext> createLowLevelContext() override
    {
        sendDataChangeMessage();
        return std::make_unique<LowLevelGraphicsSoftwareRenderer> (Image (this));
    }

    void initialiseBitmapData (Image::BitmapData& bitmap, int x, int y,
                               Image::BitmapData::ReadWriteMode mode) override
    {
        const auto offset = (size_t) (x * pixelStride + y * lineStride);
        bitmap.data = imageData + offset;
        bitmap.size = (size_t) (lineStride * height) - offset;
        bitmap.pixelFormat = pixelFormat;
        bitmap.lineStride = lineStride;
        bitmap.pixelStride = pixelStride;

        if (mode != Image::BitmapData::readOnly)
            sendDataChangeMessage();
    }

    ImagePixelData::Ptr clone() override
    {
        jassertfalse;
        return nullptr;
    }

    std::unique_ptr<ImageType> createType() const override     { return std::make_unique<NativeImageType>(); }

    void blitToWindow (::Window window, int dx, int dy, unsigned int dw, unsigned int dh, int sx, int sy)
    {
        XWindowSystemUtilities::ScopedXLock xLock;

       #if JUCE_USE_XSHM
        if (isUsingXShm())
            XWindowSystem::getInstance()->addPendingPaintForWindow (window);
       #endif

        if (gc == None)
        {
            XGCValues gcvalues;
            gcvalues.foreground = None;
            gcvalues.background = None;
            gcvalues.function = GXcopy;
            gcvalues.plane_mask = AllPlanes;
            gcvalues.clip_mask = None;
            gcvalues.graphics_exposures = False;

            gc = X11Symbols::getInstance()->xCreateGC (display, window,
                                                       GCBackground | GCForeground | GCFunction | GCPlaneMask | GCClipMask | GCGraphicsExposures,
                                                       &gcvalues);
        }

        if (imageDepth == 16)
        {
            auto rMask   = (uint32) xImage->red_mask;
            auto gMask   = (uint32) xImage->green_mask;
            auto bMask   = (uint32) xImage->blue_mask;
            auto rShiftL = (uint32) jmax (0,  getShiftNeeded (rMask));
            auto rShiftR = (uint32) jmax (0, -getShiftNeeded (rMask));
            auto gShiftL = (uint32) jmax (0,  getShiftNeeded (gMask));
            auto gShiftR = (uint32) jmax (0, -getShiftNeeded (gMask));
            auto bShiftL = (uint32) jmax (0,  getShiftNeeded (bMask));
            auto bShiftR = (uint32) jmax (0, -getShiftNeeded (bMask));

            Image::BitmapData srcData (Image (this), Image::BitmapData::readOnly);

            for (int y = sy; y < sy + (int) dh; ++y)
            {
                auto* p = srcData.getPixelPointer (sx, y);

                for (int x = sx; x < sx + (int) dw; ++x)
                {
                    auto* pixel = (PixelRGB*) p;
                    p += srcData.pixelStride;

                    X11Symbols::getInstance()->xPutPixel (xImage.get(), x, y,
                                                              (((((uint32) pixel->getRed())   << rShiftL) >> rShiftR) & rMask)
                                                            | (((((uint32) pixel->getGreen()) << gShiftL) >> gShiftR) & gMask)
                                                            | (((((uint32) pixel->getBlue())  << bShiftL) >> bShiftR) & bMask));
                }
            }
        }

        // blit results to screen.
       #if JUCE_USE_XSHM
        if (isUsingXShm())
            X11Symbols::getInstance()->xShmPutImage (display, (::Drawable) window, gc, xImage.get(), sx, sy, dx, dy, dw, dh, True);
        else
       #endif
            X11Symbols::getInstance()->xPutImage (display, (::Drawable) window, gc, xImage.get(), sx, sy, dx, dy, dw, dh);
    }

    #if JUCE_USE_XSHM
     bool isUsingXShm() const noexcept       { return usingXShm; }
    #endif

private:
    //==============================================================================
    struct Deleter
    {
        void operator() (XImage* img) const noexcept
        {
            X11Symbols::getInstance()->xDestroyImage (img);
        }
    };

    std::unique_ptr<XImage, Deleter> xImage;
    const unsigned int imageDepth;
    HeapBlock<uint8> imageDataAllocated;
    HeapBlock<char> imageData16Bit;
    int pixelStride, lineStride;
    uint8* imageData = nullptr;
    GC gc = None;
    ::Display* display = XWindowSystem::getInstance()->getDisplay();

   #if JUCE_USE_XSHM
    XShmSegmentInfo segmentInfo;
    bool usingXShm;
   #endif

    static int getShiftNeeded (const uint32 mask) noexcept
    {
        for (int i = 32; --i >= 0;)
            if (((mask >> i) & 1) != 0)
                return i - 7;

        jassertfalse;
        return 0;
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (XBitmapImage)
};

//=============================== X11 - Displays ===============================
namespace DisplayHelpers
{
    static double getDisplayDPI (::Display* display, int index)
    {
        auto widthMM  = X11Symbols::getInstance()->xDisplayWidthMM  (display, index);
        auto heightMM = X11Symbols::getInstance()->xDisplayHeightMM (display, index);

        if (widthMM > 0 && heightMM > 0)
            return (((X11Symbols::getInstance()->xDisplayWidth (display, index) * 25.4) / widthMM)
                    + ((X11Symbols::getInstance()->xDisplayHeight (display, index) * 25.4) / heightMM)) / 2.0;

        return 96.0;
    }

    static double getDisplayScale (const String& name, double dpi)
    {
        if (auto* xSettings = XWindowSystem::getInstance()->getXSettings())
        {
            auto windowScalingFactorSetting = xSettings->getSetting (XWindowSystem::getWindowScalingFactorSettingName());

            if (windowScalingFactorSetting.isValid()
                && windowScalingFactorSetting.integerValue > 0)
            {
                return (double) windowScalingFactorSetting.integerValue;
            }
        }

        if (name.isNotEmpty())
        {
            // Ubuntu and derived distributions now save a per-display scale factor as a configuration
            // variable. This can be changed in the Monitor system settings panel.
            ChildProcess dconf;

            if (File ("/usr/bin/dconf").existsAsFile()
                && dconf.start ("/usr/bin/dconf read /com/ubuntu/user-interface/scale-factor", ChildProcess::wantStdOut))
            {
                if (dconf.waitForProcessToFinish (200))
                {
                    auto jsonOutput = dconf.readAllProcessOutput().replaceCharacter ('\'', '"');

                    if (dconf.getExitCode() == 0 && jsonOutput.isNotEmpty())
                    {
                        auto jsonVar = JSON::parse (jsonOutput);

                        if (auto* object = jsonVar.getDynamicObject())
                        {
                            auto scaleFactorVar = object->getProperty (name);

                            if (! scaleFactorVar.isVoid())
                            {
                                auto scaleFactor = ((double) scaleFactorVar) / 8.0;

                                if (scaleFactor > 0.0)
                                    return scaleFactor;
                            }
                        }
                    }
                }
            }
        }

        {
            // Other gnome based distros now use gsettings for a global scale factor
            ChildProcess gsettings;

            if (File ("/usr/bin/gsettings").existsAsFile()
                && gsettings.start ("/usr/bin/gsettings get org.gnome.desktop.interface scaling-factor", ChildProcess::wantStdOut))
            {
                if (gsettings.waitForProcessToFinish (200))
                {
                    auto gsettingsOutput = StringArray::fromTokens (gsettings.readAllProcessOutput(), true);

                    if (gsettingsOutput.size() >= 2 && gsettingsOutput[1].length() > 0)
                    {
                        auto scaleFactor = gsettingsOutput[1].getDoubleValue();

                        if (scaleFactor > 0.0)
                            return scaleFactor;

                        return 1.0;
                    }
                }
            }
        }

        // If no scale factor is set by GNOME or Ubuntu then calculate from monitor dpi
        // We use the same approach as chromium which simply divides the dpi by 96
        // and then rounds the result
        return round (dpi / 96.0);
    }

   #if JUCE_USE_XINERAMA
    static Array<XineramaScreenInfo> xineramaQueryDisplays (::Display* display)
    {
        int major_opcode, first_event, first_error;

        if (X11Symbols::getInstance()->xQueryExtension (display, "XINERAMA", &major_opcode, &first_event, &first_error)
            && (X11Symbols::getInstance()->xineramaIsActive (display) != 0))
        {
            int numScreens;

            if (auto xinfo = makeXFreePtr (X11Symbols::getInstance()->xineramaQueryScreens (display, &numScreens)))
                return { xinfo.get(), numScreens };
        }

        return {};
    }
   #endif
}

//=============================== X11 - Pixmap =================================
namespace PixmapHelpers
{
    static Pixmap createColourPixmapFromImage (::Display* display, const Image& image)
    {
        XWindowSystemUtilities::ScopedXLock xLock;

        auto width  = (unsigned int) image.getWidth();
        auto height = (unsigned int) image.getHeight();
        HeapBlock<uint32> colour (width * height);
        int index = 0;

        for (int y = 0; y < (int) height; ++y)
            for (int x = 0; x < (int) width; ++x)
                colour[index++] = image.getPixelAt (x, y).getARGB();

        auto ximage = makeXFreePtr (X11Symbols::getInstance()->xCreateImage (display, (Visual*) CopyFromParent, 24, ZPixmap,
                                                                             0, reinterpret_cast<const char*> (colour.getData()),
                                                                             width, height, 32, 0));

        auto pixmap = X11Symbols::getInstance()->xCreatePixmap (display,
                                                                X11Symbols::getInstance()->xDefaultRootWindow (display),
                                                                width, height, 24);

        XValueHolder<GC> gc (X11Symbols::getInstance()->xCreateGC (display, pixmap, 0, nullptr),
                             [&display] (GC& g) { X11Symbols::getInstance()->xFreeGC (display, g); });
        X11Symbols::getInstance()->xPutImage (display, pixmap, gc.value, ximage.get(), 0, 0, 0, 0, width, height);

        return pixmap;
    }

    static Pixmap createMaskPixmapFromImage (::Display* display, const Image& image)
    {
        XWindowSystemUtilities::ScopedXLock xLock;

        auto width  = (unsigned int) image.getWidth();
        auto height = (unsigned int) image.getHeight();
        auto stride = (width + 7) >> 3;
        HeapBlock<char> mask;
        mask.calloc (stride * height);

        auto msbfirst = (X11Symbols::getInstance()->xBitmapBitOrder (display) == MSBFirst);

        for (unsigned int y = 0; y < height; ++y)
        {
            for (unsigned int x = 0; x < width; ++x)
            {
                auto bit = (char) (1 << (msbfirst ? (7 - (x & 7)) : (x & 7)));
                auto offset = y * stride + (x >> 3);

                if (image.getPixelAt ((int) x, (int) y).getAlpha() >= 128)
                    mask[offset] |= bit;
            }
        }

        return X11Symbols::getInstance()->xCreatePixmapFromBitmapData (display, X11Symbols::getInstance()->xDefaultRootWindow (display),
                                                                       mask.getData(), width, height, 1, 0, 1);
    }
}

//=============================== X11 - Clipboard ==============================
namespace ClipboardHelpers
{
    //==============================================================================
    // Read the content of a window property as either a locale-dependent string or an utf8 string
    // works only for strings shorter than 1000000 bytes
    static String readWindowProperty (::Display* display, Window window, Atom atom)
    {
        if (display != nullptr)
        {
            XWindowSystemUtilities::GetXProperty prop (display, window, atom, 0L, 100000, false, AnyPropertyType);

            if (prop.success)
            {
                if (prop.actualType == XWindowSystem::getInstance()->getAtoms().utf8String && prop.actualFormat == 8)
                    return String::fromUTF8 ((const char*) prop.data, (int) prop.numItems);

                if (prop.actualType == XA_STRING && prop.actualFormat == 8)
                    return String ((const char*) prop.data, prop.numItems);
            }
        }

        return {};
    }

    //==============================================================================
    // Send a SelectionRequest to the window owning the selection and waits for its answer (with a timeout) */
    static bool requestSelectionContent (::Display* display, String& selectionContent, Atom selection, Atom requestedFormat)
    {
        auto property_name = X11Symbols::getInstance()->xInternAtom (display, "JUCE_SEL", false);

        // The selection owner will be asked to set the JUCE_SEL property on the
        // juce_messageWindowHandle with the selection content
        X11Symbols::getInstance()->xConvertSelection (display, selection, requestedFormat, property_name,
                                                      juce_messageWindowHandle, CurrentTime);

        int count = 50; // will wait at most for 200 ms

        while (--count >= 0)
        {
            XEvent event;

            if (X11Symbols::getInstance()->xCheckTypedWindowEvent (display, juce_messageWindowHandle, SelectionNotify, &event))
            {
                if (event.xselection.property == property_name)
                {
                    jassert (event.xselection.requestor == juce_messageWindowHandle);

                    selectionContent = readWindowProperty (display, event.xselection.requestor, event.xselection.property);
                    return true;
                }

                return false;  // the format we asked for was denied.. (event.xselection.property == None)
            }

            // not very elegant.. we could do a select() or something like that...
            // however clipboard content requesting is inherently slow on x11, it
            // often takes 50ms or more so...
            Thread::sleep (4);
        }

        return false;
    }

    //==============================================================================
    // Called from the event loop in juce_linux_Messaging in response to SelectionRequest events
    static void handleSelection (XSelectionRequestEvent& evt)
    {
        // the selection content is sent to the target window as a window property
        XSelectionEvent reply;
        reply.type = SelectionNotify;
        reply.display = evt.display;
        reply.requestor = evt.requestor;
        reply.selection = evt.selection;
        reply.target = evt.target;
        reply.property = None; // == "fail"
        reply.time = evt.time;

        HeapBlock<char> data;
        int propertyFormat = 0;
        size_t numDataItems = 0;

        const auto& atoms = XWindowSystem::getInstance()->getAtoms();

        if (evt.selection == XA_PRIMARY || evt.selection == atoms.clipboard)
        {
            if (evt.target == XA_STRING || evt.target == atoms.utf8String)
            {
                auto localContent = XWindowSystem::getInstance()->getLocalClipboardContent();

                // Translate to utf8
                numDataItems = localContent.getNumBytesAsUTF8();
                auto numBytesRequiredToStore = numDataItems + 1;
                data.calloc (numBytesRequiredToStore);
                localContent.copyToUTF8 (data, numBytesRequiredToStore);
                propertyFormat = 8;   // bits per item
            }
            else if (evt.target == atoms.targets)
            {
                // Another application wants to know what we are able to send

                numDataItems = 2;
                data.calloc (numDataItems * sizeof (Atom));

                // Atoms are flagged as 32-bit irrespective of sizeof (Atom)
                propertyFormat = 32;

                auto* dataAtoms = unalignedPointerCast<Atom*> (data.getData());

                dataAtoms[0] = atoms.utf8String;
                dataAtoms[1] = XA_STRING;

                evt.target = XA_ATOM;
            }
        }
        else
        {
            DBG ("requested unsupported clipboard");
        }

        if (data != nullptr)
        {
            const size_t maxReasonableSelectionSize = 1000000;

            // for very big chunks of data, we should use the "INCR" protocol , which is a pain in the *ss
            if (evt.property != None && numDataItems < maxReasonableSelectionSize)
            {
                X11Symbols::getInstance()->xChangeProperty (evt.display, evt.requestor,
                                                            evt.property, evt.target,
                                                            propertyFormat, PropModeReplace,
                                                            reinterpret_cast<const unsigned char*> (data.getData()), (int) numDataItems);
                reply.property = evt.property; // " == success"
            }
        }

        X11Symbols::getInstance()->xSendEvent (evt.display, evt.requestor, 0, NoEventMask, (XEvent*) &reply);
    }
}

//==============================================================================
ComponentPeer* getPeerFor (::Window windowH)
{
    if (windowH == 0)
        return nullptr;

    XPointer peer = nullptr;

    if (auto* display = XWindowSystem::getInstance()->getDisplay())
    {
        XWindowSystemUtilities::ScopedXLock xLock;
        X11Symbols::getInstance()->xFindContext (display, (XID) windowH, windowHandleXContext, &peer);
    }

    return unalignedPointerCast<ComponentPeer*> (peer);
}

//==============================================================================
static std::unordered_map<LinuxComponentPeer*, X11DragState> dragAndDropStateMap;

XWindowSystem::XWindowSystem()
{
    xIsAvailable = X11Symbols::getInstance()->loadAllSymbols();

    if (! xIsAvailable)
        return;

    if (JUCEApplicationBase::isStandaloneApp())
    {
        // Initialise xlib for multiple thread support
        static bool initThreadCalled = false;

        if (! initThreadCalled)
        {
            if (! X11Symbols::getInstance()->xInitThreads())
            {
                // This is fatal!  Print error and closedown
                Logger::outputDebugString ("Failed to initialise xlib thread support.");
                Process::terminate();

                return;
            }

            initThreadCalled = true;
        }

        X11ErrorHandling::installXErrorHandlers();
    }

    if (! initialiseXDisplay())
    {
        if (JUCEApplicationBase::isStandaloneApp())
            X11ErrorHandling::removeXErrorHandlers();

        X11Symbols::deleteInstance();
        xIsAvailable = false;
    }
}

XWindowSystem::~XWindowSystem()
{
    if (xIsAvailable)
    {
        destroyXDisplay();

        if (JUCEApplicationBase::isStandaloneApp())
            X11ErrorHandling::removeXErrorHandlers();
    }

    X11Symbols::deleteInstance();
    clearSingletonInstance();
}

//==============================================================================
static int getAllEventsMask (bool ignoresMouseClicks)
{
    return NoEventMask | KeyPressMask | KeyReleaseMask
             | EnterWindowMask | LeaveWindowMask | PointerMotionMask | KeymapStateMask
             | ExposureMask | StructureNotifyMask | FocusChangeMask | PropertyChangeMask
             | (ignoresMouseClicks ? 0 : (ButtonPressMask | ButtonReleaseMask));
}

::Window XWindowSystem::createWindow (::Window parentToAddTo, LinuxComponentPeer* peer) const
{
    if (! xIsAvailable)
    {
        // can't open a window on a system that doesn't have X11 installed!
        jassertfalse;
        return 0;
    }

    auto styleFlags = peer->getStyleFlags();

    XWindowSystemUtilities::ScopedXLock xLock;

    auto root = X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display));

    auto visualAndDepth = displayVisuals->getBestVisualForWindow ((styleFlags & ComponentPeer::windowIsSemiTransparent) != 0);

    auto colormap = X11Symbols::getInstance()->xCreateColormap (display, root, visualAndDepth.visual, AllocNone);
    X11Symbols::getInstance()->xInstallColormap (display, colormap);

    // Set up the window attributes
    XSetWindowAttributes swa;
    swa.border_pixel = 0;
    swa.background_pixmap = None;
    swa.colormap = colormap;
    swa.override_redirect = ((styleFlags & ComponentPeer::windowIsTemporary) != 0) ? True : False;
    swa.event_mask = getAllEventsMask (styleFlags & ComponentPeer::windowIgnoresMouseClicks);

    auto windowH = X11Symbols::getInstance()->xCreateWindow (display, parentToAddTo != 0 ? parentToAddTo : root,
                                                             0, 0, 1, 1,
                                                             0, visualAndDepth.depth, InputOutput, visualAndDepth.visual,
                                                             CWBorderPixel | CWColormap | CWBackPixmap | CWEventMask | CWOverrideRedirect,
                                                             &swa);

    // Set the window context to identify the window handle object
    if (X11Symbols::getInstance()->xSaveContext (display, (XID) windowH, windowHandleXContext, (XPointer) peer))
    {
        // Failed
        jassertfalse;

        Logger::outputDebugString ("Failed to create context information for window.\n");
        X11Symbols::getInstance()->xDestroyWindow (display, windowH);

        return 0;
    }

    // Set window manager hints
    if (auto wmHints = makeXFreePtr (X11Symbols::getInstance()->xAllocWMHints()))
    {
        wmHints->flags = InputHint | StateHint;
        wmHints->input = True;
        wmHints->initial_state = NormalState;
        X11Symbols::getInstance()->xSetWMHints (display, windowH, wmHints.get());
    }

    // Set class hint
    if (auto* app = JUCEApplicationBase::getInstance())
    {
        if (auto classHint = makeXFreePtr (X11Symbols::getInstance()->xAllocClassHint()))
        {
            auto appName = app->getApplicationName();
            classHint->res_name  = (char*) appName.getCharPointer().getAddress();
            classHint->res_class = (char*) appName.getCharPointer().getAddress();

            X11Symbols::getInstance()->xSetClassHint (display, windowH, classHint.get());
        }
    }

    // Set the window type
    setWindowType (windowH, styleFlags);

    // Define decoration
    if ((styleFlags & ComponentPeer::windowHasTitleBar) == 0)
        removeWindowDecorations (windowH);
    else
        addWindowButtons (windowH, styleFlags);

    // Associate the PID, allowing to be shut down when something goes wrong
    auto pid = (unsigned long) getpid();
    xchangeProperty (windowH, atoms.pid, XA_CARDINAL, 32, &pid, 1);

    // Set window manager protocols
    xchangeProperty (windowH, atoms.protocols, XA_ATOM, 32, atoms.protocolList, 2);

    // Set drag and drop flags
    xchangeProperty (windowH, atoms.XdndTypeList, XA_ATOM, 32, atoms.allowedMimeTypes, numElementsInArray (atoms.allowedMimeTypes));
    xchangeProperty (windowH, atoms.XdndActionList, XA_ATOM, 32, atoms.allowedActions, numElementsInArray (atoms.allowedActions));
    xchangeProperty (windowH, atoms.XdndActionDescription, XA_STRING, 8, "", 0);

    auto dndVersion = XWindowSystemUtilities::Atoms::DndVersion;
    xchangeProperty (windowH, atoms.XdndAware, XA_ATOM, 32, &dndVersion, 1);

    unsigned long info[2] = { 0, 1 };
    xchangeProperty (windowH, atoms.XembedInfo, atoms.XembedInfo, 32, (unsigned char*) info, 2);

    return windowH;
}

void XWindowSystem::destroyWindow (::Window windowH)
{
    auto* peer = dynamic_cast<LinuxComponentPeer*> (getPeerFor (windowH));

    if (peer == nullptr)
    {
        jassertfalse;
        return;
    }

   #if JUCE_X11_SUPPORTS_XEMBED
    juce_handleXEmbedEvent (peer, nullptr);
   #endif

    deleteIconPixmaps (windowH);
    dragAndDropStateMap.erase (peer);

    XWindowSystemUtilities::ScopedXLock xLock;

    XPointer handlePointer;

    if (! X11Symbols::getInstance()->xFindContext (display, (XID) windowH, windowHandleXContext, &handlePointer))
        X11Symbols::getInstance()->xDeleteContext (display, (XID) windowH, windowHandleXContext);

    X11Symbols::getInstance()->xDestroyWindow (display, windowH);

    // Wait for it to complete and then remove any events for this
    // window from the event queue.
    X11Symbols::getInstance()->xSync (display, false);

    XEvent event;
    while (X11Symbols::getInstance()->xCheckWindowEvent (display, windowH,
                                                         getAllEventsMask (peer->getStyleFlags() & ComponentPeer::windowIgnoresMouseClicks),
                                                         &event) == True)
    {}

   #if JUCE_USE_XSHM
    if (XSHMHelpers::isShmAvailable (display))
        shmPaintsPendingMap.erase (windowH);
   #endif
}

//==============================================================================
void XWindowSystem::setTitle (::Window windowH, const String& title) const
{
    jassert (windowH != 0);

    XTextProperty nameProperty{};
    char* strings[] = { const_cast<char*> (title.toRawUTF8()) };

    XWindowSystemUtilities::ScopedXLock xLock;

    if (X11Symbols::getInstance()->xutf8TextListToTextProperty (display,
                                                                strings,
                                                                numElementsInArray (strings),
                                                                XUTF8StringStyle,
                                                                &nameProperty) >= 0)
    {
        X11Symbols::getInstance()->xSetWMName (display, windowH, &nameProperty);
        X11Symbols::getInstance()->xSetWMIconName (display, windowH, &nameProperty);

        X11Symbols::getInstance()->xFree (nameProperty.value);
    }
}


void XWindowSystem::setIcon (::Window windowH, const Image& newIcon) const
{
    jassert (windowH != 0);

    auto dataSize = newIcon.getWidth() * newIcon.getHeight() + 2;
    HeapBlock<unsigned long> data (dataSize);

    int index = 0;
    data[index++] = (unsigned long) newIcon.getWidth();
    data[index++] = (unsigned long) newIcon.getHeight();

    for (int y = 0; y < newIcon.getHeight(); ++y)
        for (int x = 0; x < newIcon.getWidth(); ++x)
            data[index++] = (unsigned long) newIcon.getPixelAt (x, y).getARGB();

    XWindowSystemUtilities::ScopedXLock xLock;
    xchangeProperty (windowH, XWindowSystemUtilities::Atoms::getCreating (display, "_NET_WM_ICON"),
                     XA_CARDINAL, 32, data.getData(), dataSize);

    deleteIconPixmaps (windowH);

    auto wmHints = makeXFreePtr (X11Symbols::getInstance()->xGetWMHints (display, windowH));

    if (wmHints == nullptr)
        wmHints = makeXFreePtr (X11Symbols::getInstance()->xAllocWMHints());

    if (wmHints != nullptr)
    {
        wmHints->flags |= IconPixmapHint | IconMaskHint;
        wmHints->icon_pixmap = PixmapHelpers::createColourPixmapFromImage (display, newIcon);
        wmHints->icon_mask = PixmapHelpers::createMaskPixmapFromImage (display, newIcon);

        X11Symbols::getInstance()->xSetWMHints (display, windowH, wmHints.get());
    }

    X11Symbols::getInstance()->xSync (display, False);
}

void XWindowSystem::setVisible (::Window windowH, bool shouldBeVisible) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;

    if (shouldBeVisible)
        X11Symbols::getInstance()->xMapWindow (display, windowH);
    else
        X11Symbols::getInstance()->xUnmapWindow (display, windowH);
}

void XWindowSystem::setBounds (::Window windowH, Rectangle<int> newBounds, bool isFullScreen) const
{
    jassert (windowH != 0);

    if (auto* peer = getPeerFor (windowH))
    {
        if (peer->isFullScreen() && ! isFullScreen)
        {
            // When transitioning back from fullscreen, we might need to remove
            // the FULLSCREEN window property
            Atom fs = XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WM_STATE_FULLSCREEN");

            if (fs != None)
            {
                auto root = X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display));

                XClientMessageEvent clientMsg;
                clientMsg.display = display;
                clientMsg.window = windowH;
                clientMsg.type = ClientMessage;
                clientMsg.format = 32;
                clientMsg.message_type = atoms.windowState;
                clientMsg.data.l[0] = 0;  // Remove
                clientMsg.data.l[1] = (long) fs;
                clientMsg.data.l[2] = 0;
                clientMsg.data.l[3] = 1;  // Normal Source

                XWindowSystemUtilities::ScopedXLock xLock;
                X11Symbols::getInstance()->xSendEvent (display, root, false,
                                                       SubstructureRedirectMask | SubstructureNotifyMask,
                                                       (XEvent*) &clientMsg);
            }
        }

        updateConstraints (windowH, *peer);

        XWindowSystemUtilities::ScopedXLock xLock;

        if (auto hints = makeXFreePtr (X11Symbols::getInstance()->xAllocSizeHints()))
        {
            hints->flags  = USSize | USPosition;
            hints->x      = newBounds.getX();
            hints->y      = newBounds.getY();
            hints->width  = newBounds.getWidth();
            hints->height = newBounds.getHeight();
            X11Symbols::getInstance()->xSetWMNormalHints (display, windowH, hints.get());
        }

        const auto nativeWindowBorder = [&]() -> BorderSize<int>
        {
            if (const auto& frameSize = peer->getFrameSizeIfPresent())
                return frameSize->multipliedBy (peer->getPlatformScaleFactor());

            return {};
        }();

        X11Symbols::getInstance()->xMoveResizeWindow (display, windowH,
                                                      newBounds.getX() - nativeWindowBorder.getLeft(),
                                                      newBounds.getY() - nativeWindowBorder.getTop(),
                                                      (unsigned int) newBounds.getWidth(),
                                                      (unsigned int) newBounds.getHeight());
    }
}

void XWindowSystem::updateConstraints (::Window windowH) const
{
    if (auto* peer = getPeerFor (windowH))
        updateConstraints (windowH, *peer);
}

void XWindowSystem::updateConstraints (::Window windowH, ComponentPeer& peer) const
{
    XWindowSystemUtilities::ScopedXLock xLock;

    if (auto hints = makeXFreePtr (X11Symbols::getInstance()->xAllocSizeHints()))
    {
        if ((peer.getStyleFlags() & ComponentPeer::windowIsResizable) == 0)
        {
            hints->min_width  = hints->max_width  = peer.getBounds().getWidth();
            hints->min_height = hints->max_height = peer.getBounds().getHeight();
            hints->flags = PMinSize | PMaxSize;
        }
        else if (auto* c = peer.getConstrainer())
        {
            const auto windowBorder = [&]() -> BorderSize<int>
            {
                if (const auto& frameSize = peer.getFrameSizeIfPresent())
                    return *frameSize;

                return {};
            }();

            const auto factor       = peer.getPlatformScaleFactor();
            const auto leftAndRight = windowBorder.getLeftAndRight();
            const auto topAndBottom = windowBorder.getTopAndBottom();
            hints->min_width  = jmax (1, (int) (factor * c->getMinimumWidth())  - leftAndRight);
            hints->max_width  = jmax (1, (int) (factor * c->getMaximumWidth())  - leftAndRight);
            hints->min_height = jmax (1, (int) (factor * c->getMinimumHeight()) - topAndBottom);
            hints->max_height = jmax (1, (int) (factor * c->getMaximumHeight()) - topAndBottom);
            hints->flags = PMinSize | PMaxSize;
        }

        X11Symbols::getInstance()->xSetWMNormalHints (display, windowH, hints.get());
    }
}

bool XWindowSystem::contains (::Window windowH, Point<int> localPos) const
{
    ::Window root, child;
    int wx, wy;
    unsigned int ww, wh, bw, bitDepth;

    XWindowSystemUtilities::ScopedXLock xLock;

    return X11Symbols::getInstance()->xGetGeometry (display, (::Drawable) windowH, &root, &wx, &wy, &ww, &wh, &bw, &bitDepth)
          && X11Symbols::getInstance()->xTranslateCoordinates (display, windowH, windowH, localPos.getX(), localPos.getY(), &wx, &wy, &child)
          && child == None;
}

ComponentPeer::OptionalBorderSize XWindowSystem::getBorderSize (::Window windowH) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;
    auto hints = XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_FRAME_EXTENTS");

    if (hints != None)
    {
        XWindowSystemUtilities::GetXProperty prop (display, windowH, hints, 0, 4, false, XA_CARDINAL);

        if (prop.success && prop.actualFormat == 32)
        {
            auto data = prop.data;
            std::array<unsigned long, 4> sizes;

            for (auto& size : sizes)
            {
                memcpy (&size, data, sizeof (unsigned long));
                data += sizeof (unsigned long);
            }

            return ComponentPeer::OptionalBorderSize ({ (int) sizes[2], (int) sizes[0], (int) sizes[3], (int) sizes[1] });
        }
    }

    return {};
}

Rectangle<int> XWindowSystem::getWindowBounds (::Window windowH, ::Window parentWindow)
{
    jassert (windowH != 0);

    Window root, child;
    int wx = 0, wy = 0;
    unsigned int ww = 0, wh = 0, bw, bitDepth;

    XWindowSystemUtilities::ScopedXLock xLock;

    if (X11Symbols::getInstance()->xGetGeometry (display, (::Drawable) windowH, &root, &wx, &wy, &ww, &wh, &bw, &bitDepth))
    {
        int rootX = 0, rootY = 0;

        if (! X11Symbols::getInstance()->xTranslateCoordinates (display, windowH, root, 0, 0, &rootX, &rootY, &child))
            rootX = rootY = 0;

        if (parentWindow == 0)
        {
            wx = rootX;
            wy = rootY;
        }
        else
        {
            // XGetGeometry returns wx and wy relative to the parent window's origin.
            // XTranslateCoordinates returns rootX and rootY relative to the root window.
            parentScreenPosition = Point<int> (rootX - wx, rootY - wy);
        }
    }

    return { wx, wy, (int) ww, (int) wh };
}

Point<int> XWindowSystem::getPhysicalParentScreenPosition() const
{
    return parentScreenPosition;
}

void XWindowSystem::setMinimised (::Window windowH, bool shouldBeMinimised) const
{
    jassert (windowH != 0);

    if (shouldBeMinimised)
    {
        auto root = X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display));

        XClientMessageEvent clientMsg;
        clientMsg.display = display;
        clientMsg.window = windowH;
        clientMsg.type = ClientMessage;
        clientMsg.format = 32;
        clientMsg.message_type = atoms.changeState;
        clientMsg.data.l[0] = IconicState;

        XWindowSystemUtilities::ScopedXLock xLock;
        X11Symbols::getInstance()->xSendEvent (display, root, false, SubstructureRedirectMask | SubstructureNotifyMask, (XEvent*) &clientMsg);
    }
}

bool XWindowSystem::isMinimised (::Window windowH) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;
    XWindowSystemUtilities::GetXProperty prop (display, windowH, atoms.state, 0, 64, false, atoms.state);

    if (prop.success && prop.actualType == atoms.state
        && prop.actualFormat == 32 && prop.numItems > 0)
    {
        unsigned long state;
        memcpy (&state, prop.data, sizeof (unsigned long));

        return state == IconicState;
    }

    return false;
}

void XWindowSystem::setMaximised (::Window windowH, bool shouldBeMaximised) const
{
    const auto root = X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display));

    XEvent ev;
    ev.xclient.window = windowH;
    ev.xclient.type   = ClientMessage;
    ev.xclient.format = 32;
    ev.xclient.message_type = XWindowSystemUtilities::Atoms::getCreating (display, "_NET_WM_STATE");
    ev.xclient.data.l[0] = shouldBeMaximised;
    ev.xclient.data.l[1] = (long) XWindowSystemUtilities::Atoms::getCreating (display, "_NET_WM_STATE_MAXIMIZED_HORZ");
    ev.xclient.data.l[2] = (long) XWindowSystemUtilities::Atoms::getCreating (display, "_NET_WM_STATE_MAXIMIZED_VERT");
    ev.xclient.data.l[3] = 1;
    ev.xclient.data.l[4] = 0;

    XWindowSystemUtilities::ScopedXLock xLock;
    X11Symbols::getInstance()->xSendEvent (display, root, false, SubstructureRedirectMask | SubstructureNotifyMask, &ev);
}

void XWindowSystem::toFront (::Window windowH, bool) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;
    XEvent ev;
    ev.xclient.type = ClientMessage;
    ev.xclient.serial = 0;
    ev.xclient.send_event = True;
    ev.xclient.message_type = atoms.activeWin;
    ev.xclient.window = windowH;
    ev.xclient.format = 32;
    ev.xclient.data.l[0] = 2;
    ev.xclient.data.l[1] = getUserTime (windowH);
    ev.xclient.data.l[2] = 0;
    ev.xclient.data.l[3] = 0;
    ev.xclient.data.l[4] = 0;

    X11Symbols::getInstance()->xSendEvent (display, X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display)),
                                           False, SubstructureRedirectMask | SubstructureNotifyMask, &ev);

    X11Symbols::getInstance()->xSync (display, False);
}

void XWindowSystem::toBehind (::Window windowH, ::Window otherWindow) const
{
    jassert (windowH != 0 && otherWindow != 0);

    const auto topLevelA = findTopLevelWindowOf (windowH);
    const auto topLevelB = findTopLevelWindowOf (otherWindow);

    Window newStack[] = { topLevelA, topLevelB };

    XWindowSystemUtilities::ScopedXLock xLock;
    X11Symbols::getInstance()->xRestackWindows (display, newStack, numElementsInArray (newStack));
}

bool XWindowSystem::isFocused (::Window windowH) const
{
    jassert (windowH != 0);

    int revert = 0;
    Window focusedWindow = 0;
    XWindowSystemUtilities::ScopedXLock xLock;
    X11Symbols::getInstance()->xGetInputFocus (display, &focusedWindow, &revert);

    if (focusedWindow == PointerRoot)
        return false;

    return isParentWindowOf (windowH, focusedWindow);
}

::Window XWindowSystem::getFocusWindow (::Window windowH) const
{
    jassert (windowH != 0);

   #if JUCE_X11_SUPPORTS_XEMBED
    if (auto w = (::Window) juce_getCurrentFocusWindow (dynamic_cast<LinuxComponentPeer*> (getPeerFor (windowH))))
        return w;
   #endif

    return windowH;
}

bool XWindowSystem::grabFocus (::Window windowH) const
{
    jassert (windowH != 0);

    XWindowAttributes atts;
    XWindowSystemUtilities::ScopedXLock xLock;

    if (windowH != 0
        && X11Symbols::getInstance()->xGetWindowAttributes (display, windowH, &atts)
        && atts.map_state == IsViewable
        && ! isFocused (windowH))
    {
        X11Symbols::getInstance()->xSetInputFocus (display, getFocusWindow (windowH), RevertToParent, (::Time) getUserTime (windowH));
        return true;
    }

    return false;
}

bool XWindowSystem::canUseSemiTransparentWindows() const
{
   #if JUCE_USE_XRENDER
    if (XRender::hasCompositingWindowManager (display))
    {
        int matchedDepth = 0, desiredDepth = 32;

        return Visuals::findVisualFormat (display, desiredDepth, matchedDepth) != nullptr
                && matchedDepth == desiredDepth;
    }
   #endif

    return false;
}

bool XWindowSystem::canUseARGBImages() const
{
    static bool canUseARGB = false;

   #if JUCE_USE_XSHM
    static bool checked = false;

    if (! checked)
    {
        if (XSHMHelpers::isShmAvailable (display))
        {
            XWindowSystemUtilities::ScopedXLock xLock;
            XShmSegmentInfo segmentinfo;

            auto testImage = X11Symbols::getInstance()->xShmCreateImage (display,
                                                                         X11Symbols::getInstance()->xDefaultVisual (display, X11Symbols::getInstance()->xDefaultScreen (display)),
                                                                         24, ZPixmap, nullptr, &segmentinfo, 64, 64);

            canUseARGB = testImage != nullptr && testImage->bits_per_pixel == 32;
            X11Symbols::getInstance()->xDestroyImage (testImage);
        }
        else
        {
            canUseARGB = false;
        }

        checked = true;
    }
   #endif

    return canUseARGB;
}

bool XWindowSystem::isDarkModeActive() const
{
    const auto themeName = [this]() -> String
    {
        if (xSettings != nullptr)
        {
            const auto themeNameSetting = xSettings->getSetting (getThemeNameSettingName());

            if (themeNameSetting.isValid()
                && themeNameSetting.stringValue.isNotEmpty())
            {
                return themeNameSetting.stringValue;
            }
        }

        ChildProcess gsettings;

        if (File ("/usr/bin/gsettings").existsAsFile()
            && gsettings.start ("/usr/bin/gsettings get org.gnome.desktop.interface gtk-theme", ChildProcess::wantStdOut))
        {
            if (gsettings.waitForProcessToFinish (200))
                return gsettings.readAllProcessOutput();
        }

        return {};
    }();

    return (themeName.isNotEmpty()
          && (themeName.containsIgnoreCase ("dark") || themeName.containsIgnoreCase ("black")));
}

Image XWindowSystem::createImage (bool isSemiTransparent, int width, int height, bool argb) const
{
    auto visualAndDepth = displayVisuals->getBestVisualForWindow (isSemiTransparent);

   #if JUCE_USE_XSHM
    return Image (new XBitmapImage (argb ? Image::ARGB : Image::RGB,
   #else
    return Image (new XBitmapImage (Image::RGB,
   #endif
                                    (width + 31) & ~31,
                                    (height + 31) & ~31,
                                    false, (unsigned int) visualAndDepth.depth, visualAndDepth.visual));
}

void XWindowSystem::blitToWindow (::Window windowH, Image image, Rectangle<int> destinationRect, Rectangle<int> totalRect) const
{
    jassert (windowH != 0);

    auto* xbitmap = static_cast<XBitmapImage*> (image.getPixelData());

    xbitmap->blitToWindow (windowH,
                           destinationRect.getX(), destinationRect.getY(),
                           (unsigned int) destinationRect.getWidth(),
                           (unsigned int) destinationRect.getHeight(),
                           destinationRect.getX() - totalRect.getX(), destinationRect.getY() - totalRect.getY());
}

void XWindowSystem::processPendingPaintsForWindow (::Window windowH)
{
   #if JUCE_USE_XSHM
    if (! XSHMHelpers::isShmAvailable (display))
        return;

    if (getNumPaintsPendingForWindow (windowH) > 0)
    {
        XWindowSystemUtilities::ScopedXLock xLock;

        XEvent evt;
        while (X11Symbols::getInstance()->xCheckTypedWindowEvent (display, windowH, shmCompletionEvent, &evt))
            removePendingPaintForWindow (windowH);
    }
   #endif
}

int XWindowSystem::getNumPaintsPendingForWindow (::Window windowH)
{
   #if JUCE_USE_XSHM
    if (XSHMHelpers::isShmAvailable (display))
        return shmPaintsPendingMap[windowH];
   #endif

    return 0;
}

void XWindowSystem::addPendingPaintForWindow (::Window windowH)
{
   #if JUCE_USE_XSHM
    if (XSHMHelpers::isShmAvailable (display))
        ++shmPaintsPendingMap[windowH];
   #endif
}

void XWindowSystem::removePendingPaintForWindow (::Window windowH)
{
   #if JUCE_USE_XSHM
    if (XSHMHelpers::isShmAvailable (display))
        --shmPaintsPendingMap[windowH];
   #endif
}

void XWindowSystem::setScreenSaverEnabled (bool enabled) const
{
    using tXScreenSaverSuspend = void (*) (Display*, Bool);
    static tXScreenSaverSuspend xScreenSaverSuspend = nullptr;

    if (xScreenSaverSuspend == nullptr)
        if (void* h = dlopen ("libXss.so.1", RTLD_GLOBAL | RTLD_NOW))
            xScreenSaverSuspend = (tXScreenSaverSuspend) dlsym (h, "XScreenSaverSuspend");

    XWindowSystemUtilities::ScopedXLock xLock;

    if (xScreenSaverSuspend != nullptr)
        xScreenSaverSuspend (display, ! enabled);
}

Point<float> XWindowSystem::getCurrentMousePosition() const
{
    Window root, child;
    int x, y, winx, winy;
    unsigned int mask;

    XWindowSystemUtilities::ScopedXLock xLock;

    if (X11Symbols::getInstance()->xQueryPointer (display,
                                                  X11Symbols::getInstance()->xRootWindow (display,
                                                                                          X11Symbols::getInstance()->xDefaultScreen (display)),
                                                  &root, &child,
                                                  &x, &y, &winx, &winy, &mask) == False)
    {
        x = y = -1;
    }

    return { (float) x, (float) y };
}

void XWindowSystem::setMousePosition (Point<float> pos) const
{
    XWindowSystemUtilities::ScopedXLock xLock;

    auto root = X11Symbols::getInstance()->xRootWindow (display,
                                                        X11Symbols::getInstance()->xDefaultScreen (display));

    X11Symbols::getInstance()->xWarpPointer (display, None, root, 0, 0, 0, 0,
                                             roundToInt (pos.getX()), roundToInt (pos.getY()));
}

Cursor XWindowSystem::createCustomMouseCursorInfo (const Image& image, Point<int> hotspot) const
{
    if (display == nullptr)
        return {};

    XWindowSystemUtilities::ScopedXLock xLock;

    auto imageW = (unsigned int) image.getWidth();
    auto imageH = (unsigned int) image.getHeight();
    auto hotspotX = hotspot.x;
    auto hotspotY = hotspot.y;

   #if JUCE_USE_XCURSOR
    if (auto xcImage = makeDeletedPtr (X11Symbols::getInstance()->xcursorImageCreate ((int) imageW, (int) imageH),
                                       [] (XcursorImage* i) { X11Symbols::getInstance()->xcursorImageDestroy (i); }))
    {
        xcImage->xhot = (XcursorDim) hotspotX;
        xcImage->yhot = (XcursorDim) hotspotY;
        auto* dest = xcImage->pixels;

        for (int y = 0; y < (int) imageH; ++y)
            for (int x = 0; x < (int) imageW; ++x)
                *dest++ = image.getPixelAt (x, y).getARGB();

        auto result = X11Symbols::getInstance()->xcursorImageLoadCursor (display, xcImage.get());

        if (result != Cursor{})
            return result;
    }
   #endif

    auto root = X11Symbols::getInstance()->xRootWindow (display,
                                                        X11Symbols::getInstance()->xDefaultScreen (display));

    unsigned int cursorW, cursorH;
    if (! X11Symbols::getInstance()->xQueryBestCursor (display, root, imageW, imageH, &cursorW, &cursorH))
        return {};

    Image im (Image::ARGB, (int) cursorW, (int) cursorH, true);

    {
        Graphics g (im);

        if (imageW > cursorW || imageH > cursorH)
        {
            hotspotX = (hotspotX * (int) cursorW) / (int) imageW;
            hotspotY = (hotspotY * (int) cursorH) / (int) imageH;

            g.drawImage (image, Rectangle<float> ((float) imageW, (float) imageH),
                         RectanglePlacement::xLeft | RectanglePlacement::yTop | RectanglePlacement::onlyReduceInSize);
        }
        else
        {
            g.drawImageAt (image, 0, 0);
        }
    }

    auto stride = (cursorW + 7) >> 3;
    HeapBlock<char> maskPlane, sourcePlane;
    maskPlane.calloc (stride * cursorH);
    sourcePlane.calloc (stride * cursorH);

    auto msbfirst = (X11Symbols::getInstance()->xBitmapBitOrder (display) == MSBFirst);

    for (auto y = (int) cursorH; --y >= 0;)
    {
        for (auto x = (int) cursorW; --x >= 0;)
        {
            auto mask   = (char) (1 << (msbfirst ? (7 - (x & 7)) : (x & 7)));
            auto offset = (unsigned int) y * stride + ((unsigned int) x >> 3);

            auto c = im.getPixelAt (x, y);

            if (c.getAlpha() >= 128)        maskPlane[offset]   |= mask;
            if (c.getBrightness() >= 0.5f)  sourcePlane[offset] |= mask;
        }
    }

    auto xFreePixmap = [this] (Pixmap& p) { X11Symbols::getInstance()->xFreePixmap (display, p); };
    XValueHolder<Pixmap> sourcePixmap (X11Symbols::getInstance()->xCreatePixmapFromBitmapData (display, root, sourcePlane.getData(), cursorW, cursorH, 0xffff, 0, 1), xFreePixmap);
    XValueHolder<Pixmap> maskPixmap   (X11Symbols::getInstance()->xCreatePixmapFromBitmapData (display, root, maskPlane.getData(),   cursorW, cursorH, 0xffff, 0, 1), xFreePixmap);

    XColor white, black;
    black.red = black.green = black.blue = 0;
    white.red = white.green = white.blue = 0xffff;

    return X11Symbols::getInstance()->xCreatePixmapCursor (display, sourcePixmap.value, maskPixmap.value, &white, &black,
                                                           (unsigned int) hotspotX, (unsigned int) hotspotY);
}

void XWindowSystem::deleteMouseCursor (Cursor cursorHandle) const
{
    if (cursorHandle != Cursor{} && display != nullptr)
    {
        XWindowSystemUtilities::ScopedXLock xLock;
        X11Symbols::getInstance()->xFreeCursor (display, (Cursor) cursorHandle);
    }
}

static Cursor createDraggingHandCursor()
{
    constexpr unsigned char dragHandData[] = {
        71,73,70,56,57,97,16,0,16,0,145,2,0,0,0,0,255,255,255,0,0,0,0,0,0,33,249,4,1,0,0,2,0,44,0,0,0,0,16,0,16,0,
        0,2,52,148,47,0,200,185,16,130,90,12,74,139,107,84,123,39,132,117,151,116,132,146,248,60,209,138,98,22,203,
        114,34,236,37,52,77,217, 247,154,191,119,110,240,193,128,193,95,163,56,60,234,98,135,2,0,59
    };

    auto image = ImageFileFormat::loadFrom (dragHandData, (size_t) numElementsInArray (dragHandData));
    return XWindowSystem::getInstance()->createCustomMouseCursorInfo (std::move (image), { 8, 7 });
}

Cursor XWindowSystem::createStandardMouseCursor (MouseCursor::StandardCursorType type) const
{
    if (display == nullptr)
        return None;

    unsigned int shape;

    switch (type)
    {
        case MouseCursor::NormalCursor:
        case MouseCursor::ParentCursor:                  return None; // Use parent cursor
        case MouseCursor::NoCursor:                      return XWindowSystem::createCustomMouseCursorInfo (Image (Image::ARGB, 16, 16, true), {});

        case MouseCursor::WaitCursor:                    shape = XC_watch; break;
        case MouseCursor::IBeamCursor:                   shape = XC_xterm; break;
        case MouseCursor::PointingHandCursor:            shape = XC_hand2; break;
        case MouseCursor::LeftRightResizeCursor:         shape = XC_sb_h_double_arrow; break;
        case MouseCursor::UpDownResizeCursor:            shape = XC_sb_v_double_arrow; break;
        case MouseCursor::UpDownLeftRightResizeCursor:   shape = XC_fleur; break;
        case MouseCursor::TopEdgeResizeCursor:           shape = XC_top_side; break;
        case MouseCursor::BottomEdgeResizeCursor:        shape = XC_bottom_side; break;
        case MouseCursor::LeftEdgeResizeCursor:          shape = XC_left_side; break;
        case MouseCursor::RightEdgeResizeCursor:         shape = XC_right_side; break;
        case MouseCursor::TopLeftCornerResizeCursor:     shape = XC_top_left_corner; break;
        case MouseCursor::TopRightCornerResizeCursor:    shape = XC_top_right_corner; break;
        case MouseCursor::BottomLeftCornerResizeCursor:  shape = XC_bottom_left_corner; break;
        case MouseCursor::BottomRightCornerResizeCursor: shape = XC_bottom_right_corner; break;
        case MouseCursor::CrosshairCursor:               shape = XC_crosshair; break;
        case MouseCursor::DraggingHandCursor:            return createDraggingHandCursor();

        case MouseCursor::CopyingCursor:
        {
            constexpr unsigned char copyCursorData[] = {
                71,73,70,56,57,97,21,0,21,0,145,0,0,0,0,0,255,255,255,0,128,128,255,255,255,33,249,4,1,0,0,3,0,44,0,0,0,0,
                21,0,21,0,0,2,72,4,134,169,171,16,199,98,11,79,90,71,161,93,56,111,78,133,218,215,137,31,82,154,100,200,
                86,91,202,142,12,108,212,87,235,174,15,54,214,126,237,226,37,96,59,141,16,37,18,201,142,157,230,204,51,112,
                252,114,147,74,83,5,50,68,147,208,217,16,71,149,252,124,5,0,59,0,0
            };

            auto image = ImageFileFormat::loadFrom (copyCursorData, (size_t) numElementsInArray (copyCursorData));
            return createCustomMouseCursorInfo (std::move (image), { 1, 3 });
        }

        case MouseCursor::NumStandardCursorTypes:
        default:
        {
            jassertfalse;
            return None;
        }
    }

    XWindowSystemUtilities::ScopedXLock xLock;

    return X11Symbols::getInstance()->xCreateFontCursor (display, shape);
}

void XWindowSystem::showCursor (::Window windowH, Cursor cursorHandle) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;
    X11Symbols::getInstance()->xDefineCursor (display, windowH, (Cursor) cursorHandle);
}

bool XWindowSystem::isKeyCurrentlyDown (int keyCode) const
{
    int keysym;

    if (keyCode & Keys::extendedKeyModifier)
    {
        keysym = 0xff00 | (keyCode & 0xff);
    }
    else
    {
        keysym = keyCode;

        if (keysym == (XK_Tab & 0xff)
            || keysym == (XK_Return & 0xff)
            || keysym == (XK_Escape & 0xff)
            || keysym == (XK_BackSpace & 0xff))
        {
            keysym |= 0xff00;
        }
    }

    XWindowSystemUtilities::ScopedXLock xLock;

    auto keycode = X11Symbols::getInstance()->xKeysymToKeycode (display, (KeySym) keysym);
    auto keybyte = keycode >> 3;
    auto keybit = (1 << (keycode & 7));

    return (Keys::keyStates [keybyte] & keybit) != 0;
}

ModifierKeys XWindowSystem::getNativeRealtimeModifiers() const
{
    ::Window root, child;
    int x, y, winx, winy;
    unsigned int mask;
    int mouseMods = 0;

    XWindowSystemUtilities::ScopedXLock xLock;

    if (X11Symbols::getInstance()->xQueryPointer (display,
                                                  X11Symbols::getInstance()->xRootWindow (display,
                                                                                          X11Symbols::getInstance()->xDefaultScreen (display)),
                                                  &root, &child, &x, &y, &winx, &winy, &mask) != False)
    {
        if ((mask & Button1Mask) != 0)  mouseMods |= ModifierKeys::leftButtonModifier;
        if ((mask & Button2Mask) != 0)  mouseMods |= ModifierKeys::middleButtonModifier;
        if ((mask & Button3Mask) != 0)  mouseMods |= ModifierKeys::rightButtonModifier;
    }

    ModifierKeys::currentModifiers = ModifierKeys::currentModifiers.withoutMouseButtons().withFlags (mouseMods);

    // We are keeping track of the state of modifier keys and mouse buttons with the assumption that
    // for every mouse down we are going to receive a mouse up etc.
    //
    // This assumption is broken when getNativeRealtimeModifiers() is called. If for example we call
    // this function when the mouse cursor is in another application and the mouse button happens to
    // be down, then its represented state in currentModifiers may remain down indefinitely, since
    // we aren't going to receive an event when it's released.
    //
    // We mark this state in this variable, and we can restore synchronization when our window
    // receives an event again.
    Keys::modifierKeysAreStale = true;

    return ModifierKeys::currentModifiers;
}

static bool hasWorkAreaData (const XWindowSystemUtilities::GetXProperty& prop)
{
    return prop.success
        && prop.actualType == XA_CARDINAL
        && prop.actualFormat == 32
        && prop.numItems == 4
        && prop.data != nullptr;
}

static Rectangle<int> getWorkArea (const XWindowSystemUtilities::GetXProperty& prop)
{
    if (hasWorkAreaData (prop))
    {
        auto* positionData = prop.data;
        std::array<long, 4> position;

        for (auto& p : position)
        {
            memcpy (&p, positionData, sizeof (long));
            positionData += sizeof (long);
        }

        return { (int) position[0], (int) position[1],
                 (int) position[2], (int) position[3] };
    }

    return {};
}

Array<Displays::Display> XWindowSystem::findDisplays (float masterScale) const
{
    Array<Displays::Display> displays;
    auto workAreaHints = XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WORKAREA");

   #if JUCE_USE_XRANDR
    if (workAreaHints != None)
    {
        int major_opcode, first_event, first_error;

        if (X11Symbols::getInstance()->xQueryExtension (display, "RANDR", &major_opcode, &first_event, &first_error))
        {
            auto numMonitors = X11Symbols::getInstance()->xScreenCount (display);
            auto mainDisplay = X11Symbols::getInstance()->xRRGetOutputPrimary (display, X11Symbols::getInstance()->xRootWindow (display, 0));

            for (int i = 0; i < numMonitors; ++i)
            {
                auto rootWindow = X11Symbols::getInstance()->xRootWindow (display, i);
                XWindowSystemUtilities::GetXProperty prop (display, rootWindow, workAreaHints, 0, 4, false, XA_CARDINAL);

                if (! hasWorkAreaData (prop))
                    continue;

                if (auto screens = makeDeletedPtr (X11Symbols::getInstance()->xRRGetScreenResources (display, rootWindow),
                                                   [] (XRRScreenResources* srs) { X11Symbols::getInstance()->xRRFreeScreenResources (srs); }))
                {
                    for (int j = 0; j < screens->noutput; ++j)
                    {
                        if (screens->outputs[j])
                        {
                            // Xrandr on the raspberry pi fails to determine the main display (mainDisplay == 0)!
                            // Detect this edge case and make the first found display the main display
                            if (! mainDisplay)
                                mainDisplay = screens->outputs[j];

                            if (auto output = makeDeletedPtr (X11Symbols::getInstance()->xRRGetOutputInfo (display, screens.get(), screens->outputs[j]),
                                                              [] (XRROutputInfo* oi) { X11Symbols::getInstance()->xRRFreeOutputInfo (oi); }))
                            {
                                if (output->crtc)
                                {
                                    if (auto crtc = makeDeletedPtr (X11Symbols::getInstance()->xRRGetCrtcInfo (display, screens.get(), output->crtc),
                                                                    [] (XRRCrtcInfo* ci) { X11Symbols::getInstance()->xRRFreeCrtcInfo (ci); }))
                                    {
                                        Displays::Display d;
                                        d.totalArea = { crtc->x, crtc->y, (int) crtc->width, (int) crtc->height };
                                        d.isMain = (mainDisplay == screens->outputs[j]) && (i == 0);
                                        d.dpi = DisplayHelpers::getDisplayDPI (display, 0);

                                        // The raspberry pi returns a zero sized display, so we need to guard for divide-by-zero
                                        if (output->mm_width > 0 && output->mm_height > 0)
                                            d.dpi = ((static_cast<double> (crtc->width)  * 25.4 * 0.5) / static_cast<double> (output->mm_width))
                                                  + ((static_cast<double> (crtc->height) * 25.4 * 0.5) / static_cast<double> (output->mm_height));

                                        auto scale = DisplayHelpers::getDisplayScale (output->name, d.dpi);
                                        scale = (scale <= 0.1 || ! JUCEApplicationBase::isStandaloneApp()) ? 1.0 : scale;

                                        d.scale = masterScale * scale;

                                        if (d.isMain)
                                            displays.insert (0, d);
                                        else
                                            displays.add (d);
                                    }
                                }
                            }
                        }
                    }
                }
            }

            if (! displays.isEmpty() && ! displays.getReference (0).isMain)
                displays.getReference (0).isMain = true;
        }
    }

    if (displays.isEmpty())
   #endif
   #if JUCE_USE_XINERAMA
    {
        auto screens = DisplayHelpers::xineramaQueryDisplays (display);
        auto numMonitors = screens.size();

        for (int index = 0; index < numMonitors; ++index)
        {
            for (auto j = numMonitors; --j >= 0;)
            {
                if (screens[j].screen_number == index)
                {
                    Displays::Display d;
                    d.totalArea = { screens[j].x_org, screens[j].y_org,
                                    screens[j].width, screens[j].height };
                    d.isMain = (index == 0);
                    d.scale = masterScale;
                    d.dpi = DisplayHelpers::getDisplayDPI (display, 0); // (all screens share the same DPI)

                    displays.add (d);
                }
            }
        }
    }

    if (displays.isEmpty())
   #endif
    {
        if (workAreaHints != None)
        {
            auto numMonitors = X11Symbols::getInstance()->xScreenCount (display);

            for (int i = 0; i < numMonitors; ++i)
            {
                XWindowSystemUtilities::GetXProperty prop (display,
                                                           X11Symbols::getInstance()->xRootWindow (display, i),
                                                           workAreaHints, 0, 4, false, XA_CARDINAL);

                auto workArea = getWorkArea (prop);

                if (! workArea.isEmpty())
                {
                    Displays::Display d;

                    d.totalArea = workArea;
                    d.isMain = displays.isEmpty();
                    d.scale = masterScale;
                    d.dpi = DisplayHelpers::getDisplayDPI (display, i);

                    displays.add (d);
                }
            }
        }

        if (displays.isEmpty())
        {
            Displays::Display d;
            d.totalArea = { X11Symbols::getInstance()->xDisplayWidth  (display, X11Symbols::getInstance()->xDefaultScreen (display)),
                            X11Symbols::getInstance()->xDisplayHeight (display, X11Symbols::getInstance()->xDefaultScreen (display)) };
            d.isMain = true;
            d.scale = masterScale;
            d.dpi = DisplayHelpers::getDisplayDPI (display, 0);

            displays.add (d);
        }
    }

    for (auto& d : displays)
        d.userArea = d.totalArea; // JUCE currently does not support requesting the user area on Linux

    return displays;
}

::Window XWindowSystem::createKeyProxy (::Window windowH) const
{
    jassert (windowH != 0);

    XSetWindowAttributes swa;
    swa.event_mask = KeyPressMask | KeyReleaseMask | FocusChangeMask;

    auto keyProxy = X11Symbols::getInstance()->xCreateWindow (display, windowH,
                                                              -1, -1, 1, 1, 0, 0,
                                                              InputOnly, CopyFromParent,
                                                              CWEventMask,
                                                              &swa);

    X11Symbols::getInstance()->xMapWindow (display, keyProxy);
    X11Symbols::getInstance()->xSaveContext (display, (XID) keyProxy, windowHandleXContext, (XPointer) this);

    return keyProxy;
}

void XWindowSystem::deleteKeyProxy (::Window keyProxy) const
{
    jassert (keyProxy != 0);

    XPointer handlePointer;

    if (! X11Symbols::getInstance()->xFindContext (display, (XID) keyProxy, windowHandleXContext, &handlePointer))
          X11Symbols::getInstance()->xDeleteContext (display, (XID) keyProxy, windowHandleXContext);

    X11Symbols::getInstance()->xDestroyWindow (display, keyProxy);
    X11Symbols::getInstance()->xSync (display, false);

    XEvent event;
    while (X11Symbols::getInstance()->xCheckWindowEvent (display, keyProxy, getAllEventsMask (false), &event) == True)
    {}
}

bool XWindowSystem::externalDragFileInit (LinuxComponentPeer* peer, const StringArray& files, bool, std::function<void()>&& callback) const
{
    auto& dragState = dragAndDropStateMap[peer];

    if (dragState.isDragging())
        return false;

    StringArray uriList;

    for (auto& f : files)
    {
        if (f.matchesWildcard ("?*://*", false))
            uriList.add (f);
        else
            uriList.add ("file://" + f);
    }

    return dragState.externalDragInit ((::Window) peer->getNativeHandle(), false, uriList.joinIntoString ("\r\n"), std::move (callback));
}

bool XWindowSystem::externalDragTextInit (LinuxComponentPeer* peer, const String& text, std::function<void()>&& callback) const
{
    auto& dragState = dragAndDropStateMap[peer];

    if (dragState.isDragging())
        return false;

    return dragState.externalDragInit ((::Window) peer->getNativeHandle(), true, text, std::move (callback));
}

void XWindowSystem::copyTextToClipboard (const String& clipText)
{
    localClipboardContent = clipText;

    X11Symbols::getInstance()->xSetSelectionOwner (display, XA_PRIMARY,      juce_messageWindowHandle, CurrentTime);
    X11Symbols::getInstance()->xSetSelectionOwner (display, atoms.clipboard, juce_messageWindowHandle, CurrentTime);
}

String XWindowSystem::getTextFromClipboard() const
{
    /* 1) try to read from the "CLIPBOARD" selection first (the "high
       level" clipboard that is supposed to be filled by ctrl-C
       etc). When a clipboard manager is running, the content of this
       selection is preserved even when the original selection owner
       exits.

       2) and then try to read from "PRIMARY" selection (the "legacy" selection
       filled by good old x11 apps such as xterm)
    */

    auto getContentForSelection = [this] (Atom selectionAtom) -> String
    {
        auto selectionOwner = X11Symbols::getInstance()->xGetSelectionOwner (display, selectionAtom);

        if (selectionOwner == None)
            return {};

        if (selectionOwner == juce_messageWindowHandle)
            return localClipboardContent;

        String content;

        if (! ClipboardHelpers::requestSelectionContent (display, content, selectionAtom, atoms.utf8String))
            ClipboardHelpers::requestSelectionContent (display, content, selectionAtom, XA_STRING);

        return content;
    };

    auto content = getContentForSelection (atoms.clipboard);

    if (content.isEmpty())
        content = getContentForSelection (XA_PRIMARY);

    return content;
}

//==============================================================================
::Window XWindowSystem::findTopLevelWindowOf (::Window w) const
{
    if (w == 0)
        return 0;

    Window* windowList = nullptr;
    uint32 windowListSize = 0;
    Window parent, root;

    XWindowSystemUtilities::ScopedXLock xLock;
    const auto result = X11Symbols::getInstance()->xQueryTree (display, w, &root, &parent, &windowList, &windowListSize);
    const auto deleter = makeXFreePtr (windowList);

    if (result == 0)
        return 0;

    if (parent == root)
        return w;

    return findTopLevelWindowOf (parent);
}

bool XWindowSystem::isParentWindowOf (::Window windowH, ::Window possibleChild) const
{
    if (windowH == 0 || possibleChild == 0)
        return false;

    if (possibleChild == windowH)
        return true;

    Window* windowList = nullptr;
    uint32 windowListSize = 0;
    Window parent, root;

    XWindowSystemUtilities::ScopedXLock xLock;
    const auto result = X11Symbols::getInstance()->xQueryTree (display, possibleChild, &root, &parent, &windowList, &windowListSize);
    const auto deleter = makeXFreePtr (windowList);

    if (result == 0 || parent == root)
        return false;

    return isParentWindowOf (windowH, parent);
}

bool XWindowSystem::isFrontWindow (::Window windowH) const
{
    jassert (windowH != 0);

    Window* windowList = nullptr;
    uint32 windowListSize = 0;

    XWindowSystemUtilities::ScopedXLock xLock;
    Window parent;
    auto root = X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display));

    const auto queryResult = X11Symbols::getInstance()->xQueryTree (display, root, &root, &parent, &windowList, &windowListSize);
    const auto deleter = makeXFreePtr (windowList);

    if (queryResult == 0)
        return false;

    for (int i = (int) windowListSize; --i >= 0;)
    {
        if (auto* peer = dynamic_cast<LinuxComponentPeer*> (getPeerFor (windowList[i])))
            return peer == dynamic_cast<LinuxComponentPeer*> (getPeerFor (windowH));
    }

    return false;
}

void XWindowSystem::xchangeProperty (::Window windowH, Atom property, Atom type, int format, const void* data, int numElements) const
{
    jassert (windowH != 0);

    X11Symbols::getInstance()->xChangeProperty (display, windowH, property, type, format, PropModeReplace, (const unsigned char*) data, numElements);
}

void XWindowSystem::removeWindowDecorations (::Window windowH) const
{
    jassert (windowH != 0);

    auto hints = XWindowSystemUtilities::Atoms::getIfExists (display, "_MOTIF_WM_HINTS");

    if (hints != None)
    {
        MotifWmHints motifHints;
        zerostruct (motifHints);

        motifHints.flags = 2; /* MWM_HINTS_DECORATIONS */
        motifHints.decorations = 0;

        XWindowSystemUtilities::ScopedXLock xLock;
        xchangeProperty (windowH, hints, hints, 32, &motifHints, 4);
    }

    hints = XWindowSystemUtilities::Atoms::getIfExists (display, "_WIN_HINTS");

    if (hints != None)
    {
        long gnomeHints = 0;

        XWindowSystemUtilities::ScopedXLock xLock;
        xchangeProperty (windowH, hints, hints, 32, &gnomeHints, 1);
    }

    hints = XWindowSystemUtilities::Atoms::getIfExists (display, "KWM_WIN_DECORATION");

    if (hints != None)
    {
        long kwmHints = 2; /*KDE_tinyDecoration*/

        XWindowSystemUtilities::ScopedXLock xLock;
        xchangeProperty (windowH, hints, hints, 32, &kwmHints, 1);
    }

    hints = XWindowSystemUtilities::Atoms::getIfExists (display, "_KDE_NET_WM_WINDOW_TYPE_OVERRIDE");

    if (hints != None)
    {
        XWindowSystemUtilities::ScopedXLock xLock;
        xchangeProperty (windowH, atoms.windowType, XA_ATOM, 32, &hints, 1);
    }
}

static void addAtomIfExists (bool condition, const char* key, ::Display* display, std::vector<Atom>& atoms)
{
    if (condition)
    {
        auto atom = XWindowSystemUtilities::Atoms::getIfExists (display, key);

        if (atom != None)
            atoms.push_back (atom);
    }
}

void XWindowSystem::addWindowButtons (::Window windowH, int styleFlags) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;
    auto motifAtom = XWindowSystemUtilities::Atoms::getIfExists (display, "_MOTIF_WM_HINTS");

    if (motifAtom != None)
    {
        MotifWmHints motifHints;
        zerostruct (motifHints);

        motifHints.flags = 1 | 2; /* MWM_HINTS_FUNCTIONS | MWM_HINTS_DECORATIONS */
        motifHints.decorations = 2 /* MWM_DECOR_BORDER */ | 8 /* MWM_DECOR_TITLE */ | 16; /* MWM_DECOR_MENU */

        motifHints.functions = 4 /* MWM_FUNC_MOVE */;

        if ((styleFlags & ComponentPeer::windowHasCloseButton) != 0)
            motifHints.functions |= 32; /* MWM_FUNC_CLOSE */

        if ((styleFlags & ComponentPeer::windowHasMinimiseButton) != 0)
        {
            motifHints.functions |= 8; /* MWM_FUNC_MINIMIZE */
            motifHints.decorations |= 0x20; /* MWM_DECOR_MINIMIZE */
        }

        if ((styleFlags & ComponentPeer::windowHasMaximiseButton) != 0)
        {
            motifHints.functions |= 0x10; /* MWM_FUNC_MAXIMIZE */
            motifHints.decorations |= 0x40; /* MWM_DECOR_MAXIMIZE */
        }

        if ((styleFlags & ComponentPeer::windowIsResizable) != 0)
        {
            motifHints.functions |= 2; /* MWM_FUNC_RESIZE */
            motifHints.decorations |= 0x4; /* MWM_DECOR_RESIZEH */
        }

        xchangeProperty (windowH, motifAtom, motifAtom, 32, &motifHints, 5);
    }

    auto actionsAtom = XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WM_ALLOWED_ACTIONS");

    if (actionsAtom != None)
    {
        std::vector<Atom> netHints;

        addAtomIfExists ((styleFlags & ComponentPeer::windowIsResizable)       != 0, "_NET_WM_ACTION_RESIZE",     display, netHints);
        addAtomIfExists ((styleFlags & ComponentPeer::windowHasMaximiseButton) != 0, "_NET_WM_ACTION_FULLSCREEN", display, netHints);
        addAtomIfExists ((styleFlags & ComponentPeer::windowHasMinimiseButton) != 0, "_NET_WM_ACTION_MINIMIZE",   display, netHints);
        addAtomIfExists ((styleFlags & ComponentPeer::windowHasCloseButton)    != 0, "_NET_WM_ACTION_CLOSE",      display, netHints);

        auto numHints = (int) netHints.size();

        if (numHints > 0)
            xchangeProperty (windowH, actionsAtom, XA_ATOM, 32, netHints.data(), numHints);
    }
}

void XWindowSystem::setWindowType (::Window windowH, int styleFlags) const
{
    jassert (windowH != 0);

    if (atoms.windowType != None)
    {
        auto hint = (styleFlags & ComponentPeer::windowIsTemporary) != 0
                    || ((styleFlags & ComponentPeer::windowHasDropShadow) == 0 && Desktop::canUseSemiTransparentWindows())
                        ? XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WM_WINDOW_TYPE_COMBO")
                        : XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WM_WINDOW_TYPE_NORMAL");

        if (hint != None)
            xchangeProperty (windowH, atoms.windowType, XA_ATOM, 32, &hint, 1);
    }

    if (atoms.windowState != None)
    {
        std::vector<Atom> netStateHints;

        addAtomIfExists ((styleFlags & ComponentPeer::windowAppearsOnTaskbar) == 0, "_NET_WM_STATE_SKIP_TASKBAR", display, netStateHints);
        addAtomIfExists (getPeerFor (windowH)->getComponent().isAlwaysOnTop(),      "_NET_WM_STATE_ABOVE",        display, netStateHints);

        auto numHints = (int) netStateHints.size();

        if (numHints > 0)
            xchangeProperty (windowH, atoms.windowState, XA_ATOM, 32, netStateHints.data(), numHints);
    }
}

void XWindowSystem::initialisePointerMap()
{
    auto numButtons = X11Symbols::getInstance()->xGetPointerMapping (display, nullptr, 0);
    pointerMap[2] = pointerMap[3] = pointerMap[4] = Keys::NoButton;

    if (numButtons == 2)
    {
        pointerMap[0] = Keys::LeftButton;
        pointerMap[1] = Keys::RightButton;
    }
    else if (numButtons >= 3)
    {
        pointerMap[0] = Keys::LeftButton;
        pointerMap[1] = Keys::MiddleButton;
        pointerMap[2] = Keys::RightButton;

        if (numButtons >= 5)
        {
            pointerMap[3] = Keys::WheelUp;
            pointerMap[4] = Keys::WheelDown;
        }
    }
}

void XWindowSystem::deleteIconPixmaps (::Window windowH) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::ScopedXLock xLock;

    if (auto wmHints = makeXFreePtr (X11Symbols::getInstance()->xGetWMHints (display, windowH)))
    {
        if ((wmHints->flags & IconPixmapHint) != 0)
        {
            wmHints->flags &= ~IconPixmapHint;
            X11Symbols::getInstance()->xFreePixmap (display, wmHints->icon_pixmap);
        }

        if ((wmHints->flags & IconMaskHint) != 0)
        {
            wmHints->flags &= ~IconMaskHint;
            X11Symbols::getInstance()->xFreePixmap (display, wmHints->icon_mask);
        }

        X11Symbols::getInstance()->xSetWMHints (display, windowH, wmHints.get());
    }
}

// Alt and Num lock are not defined by standard X modifier constants: check what they're mapped to
void XWindowSystem::updateModifierMappings() const
{
    XWindowSystemUtilities::ScopedXLock xLock;
    auto altLeftCode = X11Symbols::getInstance()->xKeysymToKeycode (display, XK_Alt_L);
    auto numLockCode = X11Symbols::getInstance()->xKeysymToKeycode (display, XK_Num_Lock);

    Keys::AltMask = 0;
    Keys::NumLockMask = 0;

    if (auto mapping = makeDeletedPtr (X11Symbols::getInstance()->xGetModifierMapping (display),
                                       [] (XModifierKeymap* mk) { X11Symbols::getInstance()->xFreeModifiermap (mk); }))
    {
        for (int modifierIdx = 0; modifierIdx < 8; ++modifierIdx)
        {
            for (int keyIndex = 0; keyIndex < mapping->max_keypermod; ++keyIndex)
            {
                auto key = mapping->modifiermap[(modifierIdx * mapping->max_keypermod) + keyIndex];

                if (key == altLeftCode)
                    Keys::AltMask = 1 << modifierIdx;
                else if (key == numLockCode)
                    Keys::NumLockMask = 1 << modifierIdx;
            }
        }
    }
}

long XWindowSystem::getUserTime (::Window windowH) const
{
    jassert (windowH != 0);

    XWindowSystemUtilities::GetXProperty prop (display, windowH, atoms.userTime, 0, 65536, false, XA_CARDINAL);

    if (! prop.success)
        return 0;

    long result = 0;
    std::memcpy (&result, prop.data, sizeof (long));

    return result;
}

void XWindowSystem::initialiseXSettings()
{
    xSettings = XWindowSystemUtilities::XSettings::createXSettings (display);

    if (xSettings != nullptr)
        X11Symbols::getInstance()->xSelectInput (display,
                                                 xSettings->getSettingsWindow(),
                                                 StructureNotifyMask | PropertyChangeMask);
}

XWindowSystem::DisplayVisuals::DisplayVisuals (::Display* xDisplay)
{
    auto findVisualWithDepthOrNull = [&] (int desiredDepth) -> Visual*
    {
        int matchedDepth = 0;
        auto* visual = Visuals::findVisualFormat (xDisplay, desiredDepth, matchedDepth);

        if (desiredDepth == matchedDepth)
            return visual;

        return nullptr;
    };

    visual16Bit = findVisualWithDepthOrNull (16);
    visual24Bit = findVisualWithDepthOrNull (24);
    visual32Bit = findVisualWithDepthOrNull (32);
}

XWindowSystem::VisualAndDepth XWindowSystem::DisplayVisuals::getBestVisualForWindow (bool isSemiTransparent) const
{
    if (isSemiTransparent && visual32Bit != nullptr)
        return { visual32Bit, 32 };

    if (visual24Bit != nullptr)
        return { visual24Bit, 24 };

    return { visual16Bit, 16 };
}

bool XWindowSystem::DisplayVisuals::isValid() const noexcept
{
    return (visual32Bit != nullptr || visual24Bit != nullptr || visual16Bit != nullptr);
}

//==============================================================================
bool XWindowSystem::initialiseXDisplay()
{
    jassert (display == nullptr);

    String displayName (getenv ("DISPLAY"));

    if (displayName.isEmpty())
        displayName = ":0.0";

    // it seems that on some systems XOpenDisplay will occasionally
    // fail the first time, but succeed on a second attempt..
    for (int retries = 2; --retries >= 0;)
    {
        display = X11Symbols::getInstance()->xOpenDisplay (displayName.toUTF8());

        if (display != nullptr)
            break;
    }

    // No X Server running
    if (display == nullptr)
        return false;

   #if JUCE_DEBUG_XERRORS_SYNCHRONOUSLY
    X11Symbols::getInstance()->xSynchronize (display, True);
   #endif

    // Create a context to store user data associated with Windows we create
    windowHandleXContext = (XContext) X11Symbols::getInstance()->xrmUniqueQuark();

    // Create our message window (this will never be mapped)
    auto screen = X11Symbols::getInstance()->xDefaultScreen (display);
    auto root = X11Symbols::getInstance()->xRootWindow (display, screen);
    X11Symbols::getInstance()->xSelectInput (display, root, SubstructureNotifyMask);

    // We're only interested in client messages for this window, which are always sent
    XSetWindowAttributes swa;
    swa.event_mask = NoEventMask;
    juce_messageWindowHandle = X11Symbols::getInstance()->xCreateWindow (display, root,
                                                                         0, 0, 1, 1, 0, 0, InputOnly,
                                                                         X11Symbols::getInstance()->xDefaultVisual (display, screen),
                                                                         CWEventMask, &swa);

    X11Symbols::getInstance()->xSync (display, False);

    atoms = XWindowSystemUtilities::Atoms (display);

    initialisePointerMap();
    updateModifierMappings();
    initialiseXSettings();

   #if JUCE_USE_XSHM
    if (XSHMHelpers::isShmAvailable (display))
        shmCompletionEvent = X11Symbols::getInstance()->xShmGetEventBase (display) + ShmCompletion;
   #endif

    displayVisuals = std::make_unique<DisplayVisuals> (display);

    if (! displayVisuals->isValid())
    {
        Logger::outputDebugString ("ERROR: System doesn't support 32, 24 or 16 bit RGB display.\n");
        return false;
    }

    // Setup input event handler
    LinuxEventLoop::registerFdCallback (X11Symbols::getInstance()->xConnectionNumber (display),
                                        [this] (int)
                                        {
                                            do
                                            {
                                                XEvent evt;

                                                {
                                                    XWindowSystemUtilities::ScopedXLock xLock;

                                                    if (! X11Symbols::getInstance()->xPending (display))
                                                        return;

                                                    X11Symbols::getInstance()->xNextEvent (display, &evt);
                                                }

                                                if (evt.type == SelectionRequest && evt.xany.window == juce_messageWindowHandle)
                                                {
                                                    ClipboardHelpers::handleSelection (evt.xselectionrequest);
                                                }
                                                else if (evt.xany.window != juce_messageWindowHandle)
                                                {
                                                    windowMessageReceive (evt);
                                                }

                                            } while (display != nullptr);
                                        });

    return true;
}

void XWindowSystem::destroyXDisplay()
{
    if (xIsAvailable)
    {
        jassert (display != nullptr);

        {
            XWindowSystemUtilities::ScopedXLock xLock;

            X11Symbols::getInstance()->xDestroyWindow (display, juce_messageWindowHandle);
            juce_messageWindowHandle = 0;
            X11Symbols::getInstance()->xSync (display, True);
        }

        LinuxEventLoop::unregisterFdCallback (X11Symbols::getInstance()->xConnectionNumber (display));

        {
            XWindowSystemUtilities::ScopedXLock xLock;
            X11Symbols::getInstance()->xCloseDisplay (display);
            display = nullptr;
            displayVisuals = nullptr;
        }
    }
}

//==============================================================================
::Window juce_createKeyProxyWindow (ComponentPeer* peer);
::Window juce_createKeyProxyWindow (ComponentPeer* peer)
{
    return XWindowSystem::getInstance()->createKeyProxy ((::Window) peer->getNativeHandle());
}

void juce_deleteKeyProxyWindow (::Window keyProxy);
void juce_deleteKeyProxyWindow (::Window keyProxy)
{
    XWindowSystem::getInstance()->deleteKeyProxy (keyProxy);
}

//==============================================================================
template <typename EventType>
static Point<float> getLogicalMousePos (const EventType& e, double scaleFactor) noexcept
{
    return Point<float> ((float) e.x, (float) e.y) / scaleFactor;
}

static int64 getEventTime (::Time t)
{
    static int64 eventTimeOffset = 0x12345678;
    auto thisMessageTime = (int64) t;

    if (eventTimeOffset == 0x12345678)
        eventTimeOffset = Time::currentTimeMillis() - thisMessageTime;

    return eventTimeOffset + thisMessageTime;
}

template <typename EventType>
static int64 getEventTime (const EventType& t)
{
    return getEventTime (t.time);
}

void XWindowSystem::handleWindowMessage (LinuxComponentPeer* peer, XEvent& event) const
{
    switch (event.xany.type)
    {
        case KeyPressEventType:     handleKeyPressEvent        (peer, event.xkey);                     break;
        case KeyRelease:            handleKeyReleaseEvent      (peer, event.xkey);                     break;
        case ButtonPress:           handleButtonPressEvent     (peer, event.xbutton);                  break;
        case ButtonRelease:         handleButtonReleaseEvent   (peer, event.xbutton);                  break;
        case MotionNotify:          handleMotionNotifyEvent    (peer, event.xmotion);                  break;
        case EnterNotify:           handleEnterNotifyEvent     (peer, event.xcrossing);                break;
        case LeaveNotify:           handleLeaveNotifyEvent     (peer, event.xcrossing);                break;
        case FocusIn:               handleFocusInEvent         (peer);                                 break;
        case FocusOut:              handleFocusOutEvent        (peer);                                 break;
        case Expose:                handleExposeEvent          (peer, event.xexpose);                  break;
        case MappingNotify:         handleMappingNotify        (event.xmapping);                       break;
        case ClientMessage:         handleClientMessageEvent   (peer, event.xclient, event);           break;
        case SelectionNotify:       dragAndDropStateMap[peer].handleDragAndDropSelection (event);      break;
        case ConfigureNotify:       handleConfigureNotifyEvent (peer, event.xconfigure);               break;
        case ReparentNotify:
        case GravityNotify:         handleGravityNotify (peer);                                        break;
        case SelectionClear:        dragAndDropStateMap[peer].handleExternalSelectionClear();          break;
        case SelectionRequest:      dragAndDropStateMap[peer].handleExternalSelectionRequest (event);  break;
        case PropertyNotify:        propertyNotifyEvent        (peer, event.xproperty);                break;

        case CirculateNotify:
        case CreateNotify:
        case DestroyNotify:
        case UnmapNotify:
            break;

        case MapNotify:
            peer->handleBroughtToFront();
            break;

        default:
           #if JUCE_USE_XSHM
            if (XSHMHelpers::isShmAvailable (display))
            {
                XWindowSystemUtilities::ScopedXLock xLock;

                if (event.xany.type == shmCompletionEvent)
                    XWindowSystem::getInstance()->removePendingPaintForWindow ((::Window) peer->getNativeHandle());
            }
           #endif
            break;
    }
}

void XWindowSystem::handleKeyPressEvent (LinuxComponentPeer* peer, XKeyEvent& keyEvent) const
{
    auto oldMods = ModifierKeys::currentModifiers;
    Keys::refreshStaleModifierKeys();

    char utf8 [64] = { 0 };
    juce_wchar unicodeChar = 0;
    int keyCode = 0;
    bool keyDownChange = false;
    KeySym sym;

    {
        XWindowSystemUtilities::ScopedXLock xLock;
        updateKeyStates ((int) keyEvent.keycode, true);

        String oldLocale (::setlocale (LC_ALL, nullptr));
        ::setlocale (LC_ALL, "");
        X11Symbols::getInstance()->xLookupString (&keyEvent, utf8, sizeof (utf8), &sym, nullptr);

        if (oldLocale.isNotEmpty())
            ::setlocale (LC_ALL, oldLocale.toRawUTF8());

        unicodeChar = *CharPointer_UTF8 (utf8);
        keyCode = (int) unicodeChar;

        if (keyCode < 0x20)
            keyCode = (int) X11Symbols::getInstance()->xkbKeycodeToKeysym (display, (::KeyCode) keyEvent.keycode, 0,
                                                                           ModifierKeys::currentModifiers.isShiftDown() ? 1 : 0);

        keyDownChange = (sym != NoSymbol) && ! updateKeyModifiersFromSym (sym, true);
    }

    bool keyPressed = false;

    if ((sym & 0xff00) == 0xff00 || keyCode == XK_ISO_Left_Tab)
    {
        switch (sym)  // Translate keypad
        {
            case XK_KP_Add:         keyCode = XK_plus;      break;
            case XK_KP_Subtract:    keyCode = XK_hyphen;    break;
            case XK_KP_Divide:      keyCode = XK_slash;     break;
            case XK_KP_Multiply:    keyCode = XK_asterisk;  break;
            case XK_KP_Enter:       keyCode = XK_Return;    break;
            case XK_KP_Insert:      keyCode = XK_Insert;    break;
            case XK_Delete:
            case XK_KP_Delete:      keyCode = XK_Delete;    break;
            case XK_KP_Left:        keyCode = XK_Left;      break;
            case XK_KP_Right:       keyCode = XK_Right;     break;
            case XK_KP_Up:          keyCode = XK_Up;        break;
            case XK_KP_Down:        keyCode = XK_Down;      break;
            case XK_KP_Home:        keyCode = XK_Home;      break;
            case XK_KP_End:         keyCode = XK_End;       break;
            case XK_KP_Page_Down:   keyCode = XK_Page_Down; break;
            case XK_KP_Page_Up:     keyCode = XK_Page_Up;   break;

            case XK_KP_0:           keyCode = XK_0;         break;
            case XK_KP_1:           keyCode = XK_1;         break;
            case XK_KP_2:           keyCode = XK_2;         break;
            case XK_KP_3:           keyCode = XK_3;         break;
            case XK_KP_4:           keyCode = XK_4;         break;
            case XK_KP_5:           keyCode = XK_5;         break;
            case XK_KP_6:           keyCode = XK_6;         break;
            case XK_KP_7:           keyCode = XK_7;         break;
            case XK_KP_8:           keyCode = XK_8;         break;
            case XK_KP_9:           keyCode = XK_9;         break;

            default:                break;
        }

        switch (keyCode)
        {
            case XK_Left:
            case XK_Right:
            case XK_Up:
            case XK_Down:
            case XK_Page_Up:
            case XK_Page_Down:
            case XK_End:
            case XK_Home:
            case XK_Delete:
            case XK_Insert:
                keyPressed = true;
                keyCode = (keyCode & 0xff) | Keys::extendedKeyModifier;
                break;

            case XK_Tab:
            case XK_Return:
            case XK_Escape:
            case XK_BackSpace:
                keyPressed = true;
                keyCode &= 0xff;
                break;

            case XK_ISO_Left_Tab:
                keyPressed = true;
                keyCode = XK_Tab & 0xff;
                break;

            default:
                if (sym >= XK_F1 && sym <= XK_F35)
                {
                    keyPressed = true;
                    keyCode = static_cast<int> ((sym & 0xff) | Keys::extendedKeyModifier);
                }
                break;
        }
    }

    if (utf8[0] != 0 || ((sym & 0xff00) == 0 && sym >= 8))
        keyPressed = true;

    if (oldMods != ModifierKeys::currentModifiers)
        peer->handleModifierKeysChange();

    if (keyDownChange)
        peer->handleKeyUpOrDown (true);

    if (keyPressed)
        peer->handleKeyPress (keyCode, unicodeChar);
}

void XWindowSystem::handleKeyReleaseEvent (LinuxComponentPeer* peer, const XKeyEvent& keyEvent) const
{
    auto isKeyReleasePartOfAutoRepeat = [&]() -> bool
    {
        if (X11Symbols::getInstance()->xPending (display))
        {
            XEvent e;
            X11Symbols::getInstance()->xPeekEvent (display, &e);

            // Look for a subsequent key-down event with the same timestamp and keycode
            return e.type           == KeyPressEventType
                  && e.xkey.keycode == keyEvent.keycode
                  && e.xkey.time    == keyEvent.time;
        }

        return false;
    }();

    if (! isKeyReleasePartOfAutoRepeat)
    {
        updateKeyStates ((int) keyEvent.keycode, false);
        KeySym sym;

        {
            XWindowSystemUtilities::ScopedXLock xLock;
            sym = X11Symbols::getInstance()->xkbKeycodeToKeysym (display, (::KeyCode) keyEvent.keycode, 0, 0);
        }

        auto oldMods = ModifierKeys::currentModifiers;
        auto keyDownChange = (sym != NoSymbol) && ! updateKeyModifiersFromSym (sym, false);

        if (oldMods != ModifierKeys::currentModifiers)
            peer->handleModifierKeysChange();

        if (keyDownChange)
            peer->handleKeyUpOrDown (false);
    }
}

void XWindowSystem::handleWheelEvent (LinuxComponentPeer* peer, const XButtonPressedEvent& buttonPressEvent, float amount) const
{
    MouseWheelDetails wheel;
    wheel.deltaX = 0.0f;
    wheel.deltaY = amount;
    wheel.isReversed = false;
    wheel.isSmooth = false;
    wheel.isInertial = false;

    peer->handleMouseWheel (MouseInputSource::InputSourceType::mouse, getLogicalMousePos (buttonPressEvent, peer->getPlatformScaleFactor()),
                            getEventTime (buttonPressEvent), wheel);
}

void XWindowSystem::handleButtonPressEvent (LinuxComponentPeer* peer, const XButtonPressedEvent& buttonPressEvent, int buttonModifierFlag) const
{
    ModifierKeys::currentModifiers = ModifierKeys::currentModifiers.withFlags (buttonModifierFlag);
    peer->toFront (true);
    peer->handleMouseEvent (MouseInputSource::InputSourceType::mouse, getLogicalMousePos (buttonPressEvent, peer->getPlatformScaleFactor()),
                            ModifierKeys::currentModifiers, MouseInputSource::defaultPressure,
                            MouseInputSource::defaultOrientation, getEventTime (buttonPressEvent), {});
}

void XWindowSystem::handleButtonPressEvent (LinuxComponentPeer* peer, const XButtonPressedEvent& buttonPressEvent) const
{
    updateKeyModifiers ((int) buttonPressEvent.state);

    auto mapIndex = (uint32) (buttonPressEvent.button - Button1);

    if (mapIndex < (uint32) numElementsInArray (pointerMap))
    {
        switch (pointerMap[mapIndex])
        {
            case Keys::WheelUp:         handleWheelEvent (peer, buttonPressEvent,  50.0f / 256.0f); break;
            case Keys::WheelDown:       handleWheelEvent (peer, buttonPressEvent, -50.0f / 256.0f); break;
            case Keys::LeftButton:      handleButtonPressEvent (peer, buttonPressEvent, ModifierKeys::leftButtonModifier); break;
            case Keys::RightButton:     handleButtonPressEvent (peer, buttonPressEvent, ModifierKeys::rightButtonModifier); break;
            case Keys::MiddleButton:    handleButtonPressEvent (peer, buttonPressEvent, ModifierKeys::middleButtonModifier); break;
            default: break;
        }
    }
}

void XWindowSystem::handleButtonReleaseEvent (LinuxComponentPeer* peer, const XButtonReleasedEvent& buttonRelEvent) const
{
    updateKeyModifiers ((int) buttonRelEvent.state);

    if (peer->getParentWindow() != 0)
        peer->updateWindowBounds();

    auto mapIndex = (uint32) (buttonRelEvent.button - Button1);

    if (mapIndex < (uint32) numElementsInArray (pointerMap))
    {
        switch (pointerMap[mapIndex])
        {
            case Keys::LeftButton:      ModifierKeys::currentModifiers = ModifierKeys::currentModifiers.withoutFlags (ModifierKeys::leftButtonModifier);   break;
            case Keys::RightButton:     ModifierKeys::currentModifiers = ModifierKeys::currentModifiers.withoutFlags (ModifierKeys::rightButtonModifier);  break;
            case Keys::MiddleButton:    ModifierKeys::currentModifiers = ModifierKeys::currentModifiers.withoutFlags (ModifierKeys::middleButtonModifier); break;
            default: break;
        }
    }

    auto& dragState = dragAndDropStateMap[peer];

    if (dragState.isDragging())
        dragState.handleExternalDragButtonReleaseEvent();

    peer->handleMouseEvent (MouseInputSource::InputSourceType::mouse, getLogicalMousePos (buttonRelEvent, peer->getPlatformScaleFactor()),
                            ModifierKeys::currentModifiers, MouseInputSource::defaultPressure, MouseInputSource::defaultOrientation, getEventTime (buttonRelEvent));
}

void XWindowSystem::handleMotionNotifyEvent (LinuxComponentPeer* peer, const XPointerMovedEvent& movedEvent) const
{
    updateKeyModifiers ((int) movedEvent.state);
    Keys::refreshStaleMouseKeys();

    auto& dragState = dragAndDropStateMap[peer];

    if (dragState.isDragging())
        dragState.handleExternalDragMotionNotify();

    peer->handleMouseEvent (MouseInputSource::InputSourceType::mouse, getLogicalMousePos (movedEvent, peer->getPlatformScaleFactor()),
                            ModifierKeys::currentModifiers, MouseInputSource::defaultPressure,
                            MouseInputSource::defaultOrientation, getEventTime (movedEvent));
}

void XWindowSystem::handleEnterNotifyEvent (LinuxComponentPeer* peer, const XEnterWindowEvent& enterEvent) const
{
    if (peer->getParentWindow() != 0)
        peer->updateWindowBounds();

    if (! ModifierKeys::currentModifiers.isAnyMouseButtonDown())
    {
        updateKeyModifiers ((int) enterEvent.state);
        peer->handleMouseEvent (MouseInputSource::InputSourceType::mouse, getLogicalMousePos (enterEvent, peer->getPlatformScaleFactor()),
                                ModifierKeys::currentModifiers, MouseInputSource::defaultPressure,
                                MouseInputSource::defaultOrientation, getEventTime (enterEvent));
    }
}

void XWindowSystem::handleLeaveNotifyEvent (LinuxComponentPeer* peer, const XLeaveWindowEvent& leaveEvent) const
{
    // Suppress the normal leave if we've got a pointer grab, or if
    // it's a bogus one caused by clicking a mouse button when running
    // in a Window manager
    if (((! ModifierKeys::currentModifiers.isAnyMouseButtonDown()) && leaveEvent.mode == NotifyNormal)
         || leaveEvent.mode == NotifyUngrab)
    {
        updateKeyModifiers ((int) leaveEvent.state);
        peer->handleMouseEvent (MouseInputSource::InputSourceType::mouse, getLogicalMousePos (leaveEvent, peer->getPlatformScaleFactor()),
                                ModifierKeys::currentModifiers, MouseInputSource::defaultPressure,
                                MouseInputSource::defaultOrientation, getEventTime (leaveEvent));
    }
}

void XWindowSystem::handleFocusInEvent (LinuxComponentPeer* peer) const
{
    peer->isActiveApplication = true;

    if (isFocused ((::Window) peer->getNativeHandle()) && ! peer->focused)
    {
        peer->focused = true;
        peer->handleFocusGain();
    }
}

void XWindowSystem::handleFocusOutEvent (LinuxComponentPeer* peer) const
{
    if (! isFocused ((::Window) peer->getNativeHandle()) && peer->focused)
    {
        peer->focused = false;
        peer->isActiveApplication = false;

        peer->handleFocusLoss();
    }
}

void XWindowSystem::handleExposeEvent (LinuxComponentPeer* peer, XExposeEvent& exposeEvent) const
{
    // Batch together all pending expose events
    XEvent nextEvent;
    XWindowSystemUtilities::ScopedXLock xLock;

    // if we have opengl contexts then just repaint them all
    // regardless if this is really necessary
    peer->repaintOpenGLContexts();

    auto windowH = (::Window) peer->getNativeHandle();

    if (exposeEvent.window != windowH)
    {
        Window child;
        X11Symbols::getInstance()->xTranslateCoordinates (display, exposeEvent.window, windowH,
                                                          exposeEvent.x, exposeEvent.y, &exposeEvent.x, &exposeEvent.y,
                                                          &child);
    }

    // exposeEvent is in local window local coordinates so do not convert with
    // physicalToScaled, but rather use currentScaleFactor
    auto currentScaleFactor = peer->getPlatformScaleFactor();

    peer->repaint (Rectangle<int> (exposeEvent.x, exposeEvent.y,
                                   exposeEvent.width, exposeEvent.height) / currentScaleFactor);

    while (X11Symbols::getInstance()->xEventsQueued (display, QueuedAfterFlush) > 0)
    {
        X11Symbols::getInstance()->xPeekEvent (display, &nextEvent);

        if (nextEvent.type != Expose || nextEvent.xany.window != exposeEvent.window)
            break;

        X11Symbols::getInstance()->xNextEvent (display, &nextEvent);
        auto& nextExposeEvent = (XExposeEvent&) nextEvent.xexpose;

        peer->repaint (Rectangle<int> (nextExposeEvent.x, nextExposeEvent.y,
                                       nextExposeEvent.width, nextExposeEvent.height) / currentScaleFactor);
    }
}

void XWindowSystem::dismissBlockingModals (LinuxComponentPeer* peer) const
{
    if (peer->getComponent().isCurrentlyBlockedByAnotherModalComponent())
        if (auto* currentModalComp = Component::getCurrentlyModalComponent())
            if (auto* otherPeer = currentModalComp->getPeer())
                if ((otherPeer->getStyleFlags() & ComponentPeer::windowIsTemporary) != 0)
                    currentModalComp->inputAttemptWhenModal();
}

void XWindowSystem::handleConfigureNotifyEvent (LinuxComponentPeer* peer, XConfigureEvent& confEvent) const
{
    peer->updateWindowBounds();
    peer->updateBorderSize();
    peer->handleMovedOrResized();

    // if the native title bar is dragged, need to tell any active menus, etc.
    if ((peer->getStyleFlags() & ComponentPeer::windowHasTitleBar) != 0)
        dismissBlockingModals (peer);

    auto windowH = (::Window) peer->getNativeHandle();

    if (confEvent.window == windowH && confEvent.above != 0 && isFrontWindow (windowH))
        peer->handleBroughtToFront();
}

void XWindowSystem::handleGravityNotify (LinuxComponentPeer* peer) const
{
    peer->updateWindowBounds();
    peer->updateBorderSize();
    peer->handleMovedOrResized();
}

void XWindowSystem::propertyNotifyEvent (LinuxComponentPeer* peer, const XPropertyEvent& event) const
{
    const auto isStateChangeEvent = [&]
    {
        if (event.atom != atoms.state)
            return false;

        return isMinimised (event.window);
    };

    const auto isHidden = [&]
    {
        if (event.atom != atoms.windowState)
            return false;

        XWindowSystemUtilities::ScopedXLock xLock;
        XWindowSystemUtilities::GetXProperty prop (display, event.window, atoms.windowState, 0, 128, false, XA_ATOM);

        if (! (prop.success && prop.actualFormat == 32 && prop.actualType == XA_ATOM))
            return false;

        const auto* data = unalignedPointerCast<const long*> (prop.data);
        const auto end = data + prop.numItems;

        return std::find (data, end, atoms.windowStateHidden) != end;
    };

    if (isStateChangeEvent() || isHidden())
        dismissBlockingModals (peer);

    if (event.atom == XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_FRAME_EXTENTS"))
        peer->updateBorderSize();
}

void XWindowSystem::handleMappingNotify (XMappingEvent& mappingEvent) const
{
    if (mappingEvent.request != MappingPointer)
    {
        // Deal with modifier/keyboard mapping
        XWindowSystemUtilities::ScopedXLock xLock;
        X11Symbols::getInstance()->xRefreshKeyboardMapping (&mappingEvent);
        updateModifierMappings();
    }
}

void XWindowSystem::handleClientMessageEvent (LinuxComponentPeer* peer, XClientMessageEvent& clientMsg, XEvent& event) const
{
    if (clientMsg.message_type == atoms.protocols && clientMsg.format == 32)
    {
        auto atom = (Atom) clientMsg.data.l[0];

        if (atom == atoms.protocolList [XWindowSystemUtilities::Atoms::PING])
        {
            auto root = X11Symbols::getInstance()->xRootWindow (display, X11Symbols::getInstance()->xDefaultScreen (display));

            clientMsg.window = root;

            X11Symbols::getInstance()->xSendEvent (display, root, False, NoEventMask, &event);
            X11Symbols::getInstance()->xFlush (display);
        }
        else if (atom == atoms.protocolList [XWindowSystemUtilities::Atoms::TAKE_FOCUS])
        {
            if ((peer->getStyleFlags() & ComponentPeer::windowIgnoresKeyPresses) == 0)
            {
                XWindowAttributes atts;

                XWindowSystemUtilities::ScopedXLock xLock;
                if (clientMsg.window != 0
                     && X11Symbols::getInstance()->xGetWindowAttributes (display, clientMsg.window, &atts))
                {
                    if (atts.map_state == IsViewable)
                    {
                        auto windowH = (::Window) peer->getNativeHandle();

                        X11Symbols::getInstance()->xSetInputFocus (display, (clientMsg.window == windowH ? getFocusWindow (windowH)
                                                                                                         : clientMsg.window),
                                                                   RevertToParent, (::Time) clientMsg.data.l[1]);
                    }
                }
            }
        }
        else if (atom == atoms.protocolList [XWindowSystemUtilities::Atoms::DELETE_WINDOW])
        {
            peer->handleUserClosingWindow();
        }
    }
    else if (clientMsg.message_type == atoms.XdndEnter)
    {
        dragAndDropStateMap[peer].handleDragAndDropEnter (clientMsg, peer);
    }
    else if (clientMsg.message_type == atoms.XdndLeave)
    {
        dragAndDropStateMap[peer].handleDragAndDropExit();
    }
    else if (clientMsg.message_type == atoms.XdndPosition)
    {
        dragAndDropStateMap[peer].handleDragAndDropPosition (clientMsg, peer);
    }
    else if (clientMsg.message_type == atoms.XdndDrop)
    {
        dragAndDropStateMap[peer].handleDragAndDropDrop (clientMsg, peer);
    }
    else if (clientMsg.message_type == atoms.XdndStatus)
    {
        dragAndDropStateMap[peer].handleExternalDragAndDropStatus (clientMsg);
    }
    else if (clientMsg.message_type == atoms.XdndFinished)
    {
        dragAndDropStateMap[peer].externalResetDragAndDrop();
    }
    else if (clientMsg.message_type == atoms.XembedMsgType && clientMsg.format == 32)
    {
        handleXEmbedMessage (peer, clientMsg);
    }
}

void XWindowSystem::handleXEmbedMessage (LinuxComponentPeer* peer, XClientMessageEvent& clientMsg) const
{
    switch (clientMsg.data.l[1])
    {
        case 0:   // XEMBED_EMBEDDED_NOTIFY
            peer->setParentWindow ((::Window) clientMsg.data.l[3]);
            peer->updateWindowBounds();
            peer->getComponent().setBounds (peer->getBounds());
            break;
        case 4:   // XEMBED_FOCUS_IN
            handleFocusInEvent (peer);
            break;
        case 5:   // XEMBED_FOCUS_OUT
            handleFocusOutEvent (peer);
            break;

        default:
            break;
    }
}

//==============================================================================
void XWindowSystem::dismissBlockingModals (LinuxComponentPeer* peer, const XConfigureEvent& configure) const
{
    if (peer == nullptr)
        return;

    const auto peerHandle = peer->getWindowHandle();

    if (configure.window != peerHandle && isParentWindowOf (configure.window, peerHandle))
        dismissBlockingModals (peer);
}

void XWindowSystem::windowMessageReceive (XEvent& event)
{
    if (event.xany.window != None)
    {
       #if JUCE_X11_SUPPORTS_XEMBED
        if (! juce_handleXEmbedEvent (nullptr, &event))
       #endif
        {
            auto* instance = XWindowSystem::getInstance();

            if (auto* xSettings = instance->getXSettings())
            {
                if (event.xany.window == xSettings->getSettingsWindow())
                {
                    if (event.xany.type == PropertyNotify)
                        xSettings->update();
                    else if (event.xany.type == DestroyNotify)
                        instance->initialiseXSettings();

                    return;
                }
            }

            if (auto* peer = dynamic_cast<LinuxComponentPeer*> (getPeerFor (event.xany.window)))
            {
                XWindowSystem::getInstance()->handleWindowMessage (peer, event);
                return;
            }

            if (event.type != ConfigureNotify)
                return;

            for (auto i = ComponentPeer::getNumPeers(); --i >= 0;)
                instance->dismissBlockingModals (dynamic_cast<LinuxComponentPeer*> (ComponentPeer::getPeer (i)),
                                                 event.xconfigure);
        }
    }
    else if (event.xany.type == KeymapNotify)
    {
        auto& keymapEvent = (const XKeymapEvent&) event.xkeymap;
        memcpy (Keys::keyStates, keymapEvent.key_vector, 32);
    }
}

//==============================================================================
JUCE_IMPLEMENT_SINGLETON (XWindowSystem)

Image createSnapshotOfNativeWindow (void* window)
{
    ::Window root;
    int wx, wy;
    unsigned int ww, wh, bw, bitDepth;

    XWindowSystemUtilities::ScopedXLock xLock;

    const auto display = XWindowSystem::getInstance()->getDisplay();

    if (! X11Symbols::getInstance()->xGetGeometry (display, (::Drawable) window, &root, &wx, &wy, &ww, &wh, &bw, &bitDepth))
        return {};

    const auto scale = []
    {
        if (auto* d = Desktop::getInstance().getDisplays().getPrimaryDisplay())
            return d->scale;

        return 1.0;
    }();

    auto image = Image { new XBitmapImage { X11Symbols::getInstance()->xGetImage (display,
                                                                                  (::Drawable) window,
                                                                                  0,
                                                                                  0,
                                                                                  ww,
                                                                                  wh,
                                                                                  AllPlanes,
                                                                                  ZPixmap) } };
    return image.rescaled ((int) ((double) ww / scale), (int) ((double) wh / scale));
}

} // namespace juce