path: root/src/gui/kernel/qmotifdnd_x11.cpp

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** contained in the Technology Preview License Agreement accompanying
** this package.
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/* The following copyright notice pertains to the code as contributed
to Qt, not to Nokia's modifications. It is replicated
in doc/dnd.doc, where the documentation system can see it. */

/* Copyright 1996 Daniel Dardailler.

   Permission to use, copy, modify, distribute, and sell this software
   for any purpose is hereby granted without fee, provided that the above
   copyright notice appear in all copies and that both that copyright
   notice and this permission notice appear in supporting documentation,
   and that the name of Daniel Dardailler not be used in advertising or
   publicity pertaining to distribution of the software without specific,
   written prior permission.  Daniel Dardailler makes no representations
   about the suitability of this software for any purpose.  It is
   provided "as is" without express or implied warranty.

   Modifications Copyright 1999 Matt Koss, under the same license as
   above.
************************************************************/

/***********************************************************/
/* Motif Drag&Drop Dynamic Protocol messaging API code */
/* Only requires Xlib layer - not MT safe */
/* Author: Daniel Dardailler, daniel@x.org */
/* Adapted by: Matt Koss, koss@napri.sk */
/* Further adaptions by: Nokia Corporation and/or its subsidiary(-ies) */
/***********************************************************/

#include "qplatformdefs.h"

#include "qapplication.h"

#ifndef QT_NO_DRAGANDDROP

#include "qdebug.h"
#include "qtextcodec.h"
#include "qwidget.h"
#include "qevent.h"
#include "qt_x11_p.h"
#include "qx11info_x11.h"
#include "qiodevice.h"
#include "qdnd_p.h"

#include <stdlib.h>

QT_BEGIN_NAMESPACE

static Window sourceWindow = XNone;
static QWidget *dropWidget = 0;
static Qt::DropAction lastAcceptedAction = Qt::IgnoreAction;

static Atom Dnd_selection = 0;
static Time Dnd_selection_time;

static Atom * src_targets ;
static ushort num_src_targets ;

// Motif definitions
#define DndVersion 1
#define DndRevision 0
#define DndIncludeVersion (DndVersion * 10 + DndRevision)

/* The following values are used in the DndData structure */

/* protocol style */
#define DND_DRAG_NONE            0
#define DND_DRAG_DROP_ONLY       1
#define DND_DRAG_DYNAMIC         5

/* message type */
#define DND_TOP_LEVEL_ENTER   0
#define DND_TOP_LEVEL_LEAVE   1
#define DND_DRAG_MOTION       2
#define DND_DROP_SITE_ENTER   3
#define DND_DROP_SITE_LEAVE   4
#define DND_DROP_START        5
#define DND_OPERATION_CHANGED 8

/* operation(s) */
#define DND_NOOP        0L
#define DND_MOVE         (1L << 0)
#define DND_COPY        (1L << 1)
#define DND_LINK        (1L << 2)

static Qt::DropActions DndOperationsToQtDropActions(uchar op)
{
    Qt::DropActions actions = Qt::IgnoreAction;
    if (op | DND_MOVE)
        actions |= Qt::MoveAction;
    if (op | DND_COPY)
        actions |= Qt::CopyAction;
    if (op | DND_LINK)
        actions |= Qt::LinkAction;
    return actions;
}

static uchar QtDropActionToDndOperation(Qt::DropAction action)
{
    switch (action & Qt::ActionMask) {
    case Qt::CopyAction:
    default:
        return DND_COPY;
    case Qt::MoveAction:
        return DND_MOVE;
    case Qt::LinkAction:
        return DND_LINK;
    }
}


/* status */
#define DND_NO_DROP_SITE        1
#define DND_INVALID_DROP_SITE   2
#define DND_VALID_DROP_SITE        3

/* completion */
#define DND_DROP        0
#define DND_DROP_HELP   1
#define DND_DROP_CANCEL 2

#define BYTE unsigned char
#define CARD32 unsigned int
#define CARD16 unsigned short
#define INT16  signed short

/* Client side structure used in the API */
typedef struct {
    unsigned char       reason;  /* message type: DND_TOP_LEVEL_ENTER, etc */
    Time                time ;
    unsigned char       operation;
    unsigned char       operations;
    unsigned char       status;
    unsigned char       completion;
    short               x ;
    short               y ;
    Window              src_window ;
    Atom                property ;
} DndData ;


typedef struct _DndSrcProp {
    BYTE                byte_order ;
    BYTE                protocol_version ;
    CARD16              target_index ;
    CARD32              selection ;
} DndSrcProp ;

typedef struct _DndReceiverProp {
    BYTE                byte_order ;
    BYTE                protocol_version ;
    BYTE                protocol_style ;
    BYTE                pad1;
    CARD32              proxy_window;
    CARD16              num_drop_sites ;
    CARD16              pad2;
    CARD32              total_size;
} DndReceiverProp ;

/* need to use some union hack since window and property are in
   different order depending on the message ... */
typedef struct _DndTop {
    CARD32                src_window;
    CARD32                property;
} DndTop ;

typedef struct _DndPot {
    INT16                x;
    INT16                y;
    CARD32                property;
    CARD32                src_window;
} DndPot ;

typedef struct _DndMessage {
    BYTE                reason;
    BYTE                byte_order;
    CARD16                flags;
    CARD32                time;
    union {
        DndTop top ;
        DndPot pot ;
    } data ;
} DndMessage ;

typedef struct {
    BYTE        byte_order;
    BYTE        protocol_version;
    CARD16        num_target_lists;
    CARD32        data_size;
    /* then come series of CARD16,CARD32,CARD32,CARD32... */
} DndTargets;


/* protocol version */
#define DND_PROTOCOL_VERSION 0


#define DND_EVENT_TYPE_MASK  ((BYTE)0x80)
#define DND_EVENT_TYPE_SHIFT 7
#define DND_CLEAR_EVENT_TYPE  ((BYTE)0x7F)

/* message_type is data[0] of the client_message
   this return 1 (receiver bit up) or 0 (initiator) */
#define DND_GET_EVENT_TYPE(message_type) \
((char) (((message_type) & DND_EVENT_TYPE_MASK) >> DND_EVENT_TYPE_SHIFT))

/* event_type can be 0 (initiator) or 1 (receiver) */
#define DND_SET_EVENT_TYPE(event_type) \
(((BYTE)(event_type) << DND_EVENT_TYPE_SHIFT) & DND_EVENT_TYPE_MASK)


#define DND_OPERATION_MASK ((CARD16) 0x000F)
#define DND_OPERATION_SHIFT 0
#define DND_STATUS_MASK ((CARD16) 0x00F0)
#define DND_STATUS_SHIFT 4
#define DND_OPERATIONS_MASK ((CARD16) 0x0F00)
#define DND_OPERATIONS_SHIFT 8
#define DND_COMPLETION_MASK ((CARD16) 0xF000)
#define DND_COMPLETION_SHIFT 12

#define DND_GET_OPERATION(flags) \
((unsigned char) \
(((flags) & DND_OPERATION_MASK) >> DND_OPERATION_SHIFT))

#define DND_SET_OPERATION(operation) \
(((CARD16)(operation) << DND_OPERATION_SHIFT)\
& DND_OPERATION_MASK)

#define DND_GET_STATUS(flags) \
((unsigned char) \
(((flags) & DND_STATUS_MASK) >> DND_STATUS_SHIFT))

#define DND_SET_STATUS(status) \
(((CARD16)(status) << DND_STATUS_SHIFT)\
& DND_STATUS_MASK)

#define DND_GET_OPERATIONS(flags) \
((unsigned char) \
(((flags) & DND_OPERATIONS_MASK) >> DND_OPERATIONS_SHIFT))

#define DND_SET_OPERATIONS(operation) \
(((CARD16)(operation) << DND_OPERATIONS_SHIFT)\
& DND_OPERATIONS_MASK)

#define DND_GET_COMPLETION(flags) \
((unsigned char) \
(((flags) & DND_COMPLETION_MASK) >> DND_COMPLETION_SHIFT))

#define DND_SET_COMPLETION(completion) \
(((CARD16)(completion) << DND_COMPLETION_SHIFT)\
& DND_COMPLETION_MASK)


#define SWAP4BYTES(l) {\
struct { unsigned t :32;} bit32;\
char n, *tp = (char *) &bit32;\
bit32.t = l;\
n = tp[0]; tp[0] = tp[3]; tp[3] = n;\
n = tp[1]; tp[1] = tp[2]; tp[2] = n;\
l = bit32.t;\
}

#define SWAP2BYTES(s) {\
struct { unsigned t :16; } bit16;\
char n, *tp = (char *) &bit16;\
bit16.t = s;\
n = tp[0]; tp[0] = tp[1]; tp[1] = n;\
s = bit16.t;\
}


/** Private extern functions */

static unsigned char DndByteOrder ();


/***** Targets/Index stuff */

typedef struct {
    int            num_targets;
    Atom    *targets;
} DndTargetsTableEntryRec, * DndTargetsTableEntry;

typedef struct {
    int        num_entries;
    DndTargetsTableEntry entries;
} DndTargetsTableRec, * DndTargetsTable;


static ushort _DndIndexToTargets(Display * display,
                                 int index,
                                 Atom ** targets);

extern void qt_x11_intern_atom(const char *, Atom *);

/////////////////////////////////////////////////////////////////

static unsigned char DndByteOrder ()
{
    static unsigned char byte_order = 0;

    if (!byte_order) {
        unsigned int endian = 1;
        byte_order = (*((char *)&endian))?'l':'B';
    }
    return byte_order ;
}



static void DndReadSourceProperty(Display * dpy,
                                  Window window, Atom dnd_selection,
                                  Atom ** targets, unsigned short * num_targets)
{
    unsigned char *retval = 0;
    Atom type ;
    int format ;
    unsigned long bytesafter, lengthRtn;

    if ((XGetWindowProperty (dpy, window, dnd_selection, 0L, 100000L,
                             False, ATOM(_MOTIF_DRAG_INITIATOR_INFO), &type,
                             &format, &lengthRtn, &bytesafter,
                             &retval) != Success)
        || (type == XNone)) {
        *num_targets = 0;
        return ;
    }

    DndSrcProp * src_prop = (DndSrcProp *)retval;

    if (src_prop->byte_order != DndByteOrder()) {
        SWAP2BYTES(src_prop->target_index);
        SWAP4BYTES(src_prop->selection);
    }

    *num_targets = _DndIndexToTargets(dpy, src_prop->target_index, targets);

    XFree((char*)src_prop);
}


/* Position the _MOTIF_DRAG_RECEIVER_INFO property on the dropsite window.
   Called by the receiver of the drop to indicate the
   supported protocol style : dynamic, drop_only or none */
static void DndWriteReceiverProperty(Display * dpy, Window window,
                                     unsigned char protocol_style)
{
    DndReceiverProp receiver_prop ;

    receiver_prop.byte_order = DndByteOrder() ;
    receiver_prop.protocol_version = DND_PROTOCOL_VERSION;
    receiver_prop.protocol_style = protocol_style ;
    receiver_prop.proxy_window =  XNone ;
    receiver_prop.num_drop_sites = 0 ;
    receiver_prop.total_size = sizeof(DndReceiverProp);

    /* write the buffer to the property */
    XChangeProperty (dpy, window, ATOM(_MOTIF_DRAG_RECEIVER_INFO), ATOM(_MOTIF_DRAG_RECEIVER_INFO),
                     8, PropModeReplace,
                     (unsigned char *)&receiver_prop,
                     sizeof(DndReceiverProp));
}


/* protocol style equiv (preregister stuff really) */
#define DND_DRAG_DROP_ONLY_EQUIV 3
#define DND_DRAG_DYNAMIC_EQUIV1  2
#define DND_DRAG_DYNAMIC_EQUIV2  4


/* Produce a client message to be sent by the caller */
static void DndFillClientMessage(Display * dpy, Window window,
                                 XClientMessageEvent *cm,
                                 DndData * dnd_data,
                                 char receiver)
{
    DndMessage * dnd_message = (DndMessage*)&cm->data.b[0] ;

    cm->display = dpy;
    cm->type = ClientMessage;
    cm->serial = LastKnownRequestProcessed(dpy);
    cm->send_event = True;
    cm->window = window;
    cm->format = 8;
    cm->message_type = ATOM(_MOTIF_DRAG_AND_DROP_MESSAGE);

    dnd_message->reason = dnd_data->reason | DND_SET_EVENT_TYPE(receiver);

    dnd_message->byte_order = DndByteOrder();

    /* we're filling in flags with more stuff that necessary,
       depending on the reason, but it doesn't matter */
    dnd_message->flags = 0 ;
    dnd_message->flags |= DND_SET_STATUS(dnd_data->status) ;
    dnd_message->flags |= DND_SET_OPERATION(dnd_data->operation) ;
    dnd_message->flags |= DND_SET_OPERATIONS(dnd_data->operations) ;
    dnd_message->flags |= DND_SET_COMPLETION(dnd_data->completion) ;

    dnd_message->time = dnd_data->time ;

    switch(dnd_data->reason) {
    case DND_DROP_SITE_LEAVE: break ;
    case DND_TOP_LEVEL_ENTER:
    case DND_TOP_LEVEL_LEAVE:
        dnd_message->data.top.src_window = dnd_data->src_window ;
        dnd_message->data.top.property = dnd_data->property ;
        break ; /* cannot fall through since the byte layout is different in
                   both set of messages, see top and pot union stuff */

    case DND_DRAG_MOTION:
    case DND_OPERATION_CHANGED:
    case DND_DROP_SITE_ENTER:
    case DND_DROP_START:
        dnd_message->data.pot.x = dnd_data->x ; /* mouse position */
        dnd_message->data.pot.y = dnd_data->y ;
        dnd_message->data.pot.src_window = dnd_data->src_window ;
        dnd_message->data.pot.property = dnd_data->property ;
        break ;
    default:
        break ;
    }

}

static Bool DndParseClientMessage(XClientMessageEvent *cm, DndData * dnd_data,
                                  char * receiver)
{
    DndMessage * dnd_message = (DndMessage*)&cm->data.b[0] ;

    if (cm->message_type != ATOM(_MOTIF_DRAG_AND_DROP_MESSAGE)) {
        return False ;
    }

    if (dnd_message->byte_order != DndByteOrder()) {
        SWAP2BYTES(dnd_message->flags);
        SWAP4BYTES(dnd_message->time);
    } /* do the rest in the switch */

    dnd_data->reason = dnd_message->reason  ;
    if (DND_GET_EVENT_TYPE(dnd_data->reason))
        *receiver = 1 ;
    else
        *receiver = 0 ;
    dnd_data->reason &= DND_CLEAR_EVENT_TYPE ;

    dnd_data->time = dnd_message->time ;

    /* we're reading in more stuff that necessary. but who cares */
    dnd_data->status = DND_GET_STATUS(dnd_message->flags) ;
    dnd_data->operation = DND_GET_OPERATION(dnd_message->flags) ;
    dnd_data->operations = DND_GET_OPERATIONS(dnd_message->flags) ;
    dnd_data->completion = DND_GET_COMPLETION(dnd_message->flags) ;

    switch(dnd_data->reason) {
    case DND_TOP_LEVEL_ENTER:
    case DND_TOP_LEVEL_LEAVE:
        if (dnd_message->byte_order != DndByteOrder()) {
            SWAP4BYTES(dnd_message->data.top.src_window);
            SWAP4BYTES(dnd_message->data.top.property);
        }
        dnd_data->src_window = dnd_message->data.top.src_window ;
        dnd_data->property = dnd_message->data.top.property ;
        break ; /* cannot fall through, see above comment in write msg */

    case DND_DRAG_MOTION:
    case DND_OPERATION_CHANGED:
    case DND_DROP_SITE_ENTER:
    case DND_DROP_START:
        if (dnd_message->byte_order != DndByteOrder()) {
            SWAP2BYTES(dnd_message->data.pot.x);
            SWAP2BYTES(dnd_message->data.pot.y);
            SWAP4BYTES(dnd_message->data.pot.property);
            SWAP4BYTES(dnd_message->data.pot.src_window);
        }
        dnd_data->x = dnd_message->data.pot.x ;
        dnd_data->y = dnd_message->data.pot.y ;
        dnd_data->property = dnd_message->data.pot.property ;
        dnd_data->src_window = dnd_message->data.pot.src_window ;
        break ;

    case DND_DROP_SITE_LEAVE:
        break;
    default:
        break ;
    }

    return True ;
}


static Window MotifWindow(Display *display)
{
    Atom            type;
    int             format;
    unsigned long   size;
    unsigned long   bytes_after;
    unsigned char  *property = 0;
    Window            motif_window ;

    /* this version does no caching, so it's slow: round trip each time */

    if ((XGetWindowProperty (display, RootWindow(display, 0),
                             ATOM(_MOTIF_DRAG_WINDOW),
                             0L, 100000L, False, AnyPropertyType,
                             &type, &format, &size, &bytes_after,
                             &property) == Success) &&
        (type != XNone)) {
        motif_window = *(Window *)property;
    } else {
        XSetWindowAttributes sAttributes;

        /* really, this should be done on a separate connection,
           with XSetCloseDownMode (RetainPermanent), so that
           others don't have to recreate it; hopefully, some real
           Motif application will be around to do it */

        sAttributes.override_redirect = True;
        sAttributes.event_mask = PropertyChangeMask;
        motif_window = XCreateWindow (display,
                                      RootWindow (display, 0),
                                      -170, -560, 1, 1, 0, 0,
                                      InputOnly, CopyFromParent,
                                      (CWOverrideRedirect |CWEventMask),
                                      &sAttributes);
        XMapWindow (display, motif_window);
    }

    if (property) {
        XFree ((char *)property);
    }

    return (motif_window);
}


static DndTargetsTable TargetsTable(Display *display)
{
    Atom            type;
    int             format;
    unsigned long   size;
    unsigned long   bytes_after;
    Window motif_window = MotifWindow(display) ;
    unsigned char  *retval;
    DndTargetsTable targets_table ;
    int i,j ;
    char * target_data ;

    /* this version does no caching, so it's slow: round trip each time */
    /* ideally, register for property notify on this target_list
       atom and update when necessary only */

    if ((XGetWindowProperty (display, motif_window,
                             ATOM(_MOTIF_DRAG_TARGETS), 0L, 100000L,
                             False, ATOM(_MOTIF_DRAG_TARGETS),
                             &type, &format, &size, &bytes_after,
                             &retval) != Success) ||
        type == XNone) {
        qWarning("QMotifDND: Cannot get property on Motif window");
        return 0;
    }

    DndTargets * target_prop = (DndTargets *)retval;

    if (target_prop->protocol_version != DND_PROTOCOL_VERSION) {
        qWarning("QMotifDND: Protocol mismatch");
    }

    if (target_prop->byte_order != DndByteOrder()) {
        /* need to swap num_target_lists and size */
        SWAP2BYTES(target_prop->num_target_lists);
        SWAP4BYTES(target_prop->data_size);
    }

    /* now parse DndTarget prop data in a TargetsTable */

    targets_table = (DndTargetsTable)malloc(sizeof(DndTargetsTableRec));
    targets_table->num_entries = target_prop->num_target_lists ;
    targets_table->entries = (DndTargetsTableEntry)
                             malloc(sizeof(DndTargetsTableEntryRec) * target_prop->num_target_lists);

    target_data = (char*)target_prop + sizeof(*target_prop) ;

    for (i = 0 ; i < targets_table->num_entries; i++) {
        CARD16 num_targets ;
        CARD32 atom ;

        memcpy(&num_targets, target_data, 2);
        target_data += 2;

        /* potential swap needed here */
        if (target_prop->byte_order != DndByteOrder())
            SWAP2BYTES(num_targets);

        targets_table->entries[i].num_targets = num_targets ;
        targets_table->entries[i].targets = (Atom *)
                                            malloc(sizeof(Atom) * targets_table->entries[i].num_targets);


        for (j = 0; j < num_targets; j++) {
            memcpy(&atom, target_data, 4);
            target_data += 4;

            /* another potential swap needed here */
            if (target_prop->byte_order != DndByteOrder())
                SWAP4BYTES(atom);

            targets_table->entries[i].targets[j] = (Atom) atom ;
        }
    }

    if (target_prop) {
        XFree((char *)target_prop);
    }

    return targets_table ;
}


static ushort _DndIndexToTargets(Display * display,
                              int index,
                              Atom ** targets)
{
    DndTargetsTable        targets_table;
    int i ;

    /* again, slow: no caching here, alloc/free each time */

    if (!(targets_table = TargetsTable (display)) ||
        (index >= targets_table->num_entries)) {
        if (targets_table)
            XFree((char*)targets_table);
        return 0;
    }

    /* transfer the correct target list index */
    *targets = (Atom*)malloc(sizeof(Atom)*targets_table->
                             entries[index].num_targets);
    memcpy((char*)*targets,
           (char*)targets_table->entries[index].targets,
           sizeof(Atom)*targets_table->entries[index].num_targets);

    /* free the target table and its guts */
    for (i=0 ; i < targets_table->num_entries; i++)
        XFree((char*)targets_table->entries[i].targets);

    int tmp = targets_table->entries[index].num_targets;
    XFree((char*)targets_table);

    return tmp; // targets_table->entries[index].num_targets;
}


QByteArray QX11Data::motifdndFormat(int n)
{
    if (!motifdnd_active)
        return 0; // should not happen

    if (n >= num_src_targets)
        return 0;

    Atom target = src_targets[n];

    if (target == XA_STRING)
        return "text/plain;charset=ISO-8859-1";
    if (target == ATOM(UTF8_STRING))
        return "text/plain;charset=UTF-8";
    if (target == ATOM(COMPOUND_TEXT))
        return QByteArray("text/plain;charset=") + QTextCodec::codecForLocale()->name();
    if (target == ATOM(TEXT))
        return "text/plain";

    return ("x-motif-dnd/" + X11->xdndAtomToString(target));
}


QVariant QX11Data::motifdndObtainData(const char *mimeType)
{
    QByteArray result;

    if (Dnd_selection == 0 || !dropWidget)
        return result;

    // try to convert the selection to the requested property
    // qDebug("trying to convert to '%s'", mimeType);

    int n=0;
    QByteArray f;
    do {
        f = motifdndFormat(n);
        if (f.isEmpty())
            return result;
        n++;
    } while(qstricmp(mimeType, f.data()));

    Atom conversion_type = XNone;
    if (f == "text/plain;charset=ISO-8859-1") {
        conversion_type = XA_STRING;
    } else if (f == "text/plain;charset=UTF-8") {
        conversion_type = ATOM(UTF8_STRING);
    } else if (f == (QByteArray("text/plain;charset=") + QTextCodec::codecForLocale()->name())) {
        conversion_type = ATOM(COMPOUND_TEXT);
    } else if (f == "text/plain") {
        conversion_type = ATOM(TEXT);
    } else if (f.startsWith("x-motif-dnd/")) {
        // strip off the "x-motif-dnd/" prefix
        conversion_type = X11->xdndStringToAtom(f.remove(0, 12));
    }

    if (XGetSelectionOwner(X11->display, Dnd_selection) == XNone) {
        return result; // should never happen?
    }

    QWidget* tw = dropWidget;
    if ((dropWidget->windowType() == Qt::Desktop)) {
        tw = new QWidget;
    }

    // convert selection to the appropriate type
    XConvertSelection (X11->display, Dnd_selection, conversion_type,
                       Dnd_selection, tw->internalWinId(), Dnd_selection_time);

    XFlush(X11->display);

    XEvent xevent;
    bool got=X11->clipboardWaitForEvent(tw->internalWinId(), SelectionNotify, &xevent, 5000);
    if (got) {
        Atom type;

        if (X11->clipboardReadProperty(tw->internalWinId(), Dnd_selection, true, &result, 0, &type, 0, false)) {
        }
    }

    //   we have to convert selection in order to indicate success to the initiator
    XConvertSelection (X11->display, Dnd_selection, ATOM(XmTRANSFER_SUCCESS),
                       Dnd_selection, tw->internalWinId(), Dnd_selection_time);

    // wait again for SelectionNotify event
    X11->clipboardWaitForEvent(tw->internalWinId(), SelectionNotify, &xevent, 5000);

    if ((dropWidget->windowType() == Qt::Desktop)) {
        delete tw;
    }

    return result;
}


void QX11Data::motifdndEnable(QWidget *widget, bool)
{
    DndWriteReceiverProperty(display, widget->internalWinId(), DND_DRAG_DYNAMIC);
}


void QX11Data::motifdndHandle(QWidget *widget, const XEvent * xe, bool /* passive */)
{
    XEvent event = *xe;
    XClientMessageEvent cm ;
    DndData dnd_data ;
    char receiver ;

    if (!(DndParseClientMessage ((XClientMessageEvent*)&event,
                                 &dnd_data, &receiver))) {
        return;
    }

    switch (dnd_data.reason) {

    case DND_DRAG_MOTION:
        {
            QPoint p = widget->mapFromGlobal(QPoint(dnd_data.x, dnd_data.y));
            QWidget *c = widget->childAt(p);

            if (!c || !c->acceptDrops()) {
                // not over a drop site
                if (dropWidget) {
                    QDragLeaveEvent dragLeaveEvent;
                    QApplication::sendEvent(dropWidget, &dragLeaveEvent);

                    dropWidget = 0;
                    lastAcceptedAction = Qt::IgnoreAction;

                    dnd_data.reason = DND_DROP_SITE_LEAVE;
                    dnd_data.time = X11->time;
                    DndFillClientMessage (event.xclient.display, sourceWindow, &cm, &dnd_data, receiver);
                    XSendEvent(event.xbutton.display, sourceWindow, False, 0, (XEvent *)&cm) ;
                } else {
                    dnd_data.reason = DND_DRAG_MOTION;
                    dnd_data.status = DND_NO_DROP_SITE;
                    dnd_data.time = X11->time;
                    dnd_data.operation = DND_NOOP;
                    dnd_data.operations = DND_NOOP;
                    DndFillClientMessage (event.xclient.display, sourceWindow, &cm, &dnd_data, receiver);
                    XSendEvent(event.xbutton.display, sourceWindow, False, 0, (XEvent *)&cm) ;
                }
            } else {
                Q_ASSERT(c != 0);
                p = c->mapFrom(widget, p);

                if (dropWidget != c) {
                    if (dropWidget) {
                        QDragLeaveEvent le;
                        QApplication::sendEvent(dropWidget, &le);
                    }

                    dropWidget = c;
                    lastAcceptedAction = Qt::IgnoreAction;

                    const Qt::DropActions possibleActions =
                        DndOperationsToQtDropActions(dnd_data.operations);
                    QDragEnterEvent de(p, possibleActions, QDragManager::self()->dropData,
                                       QApplication::mouseButtons(), QApplication::keyboardModifiers());
                    QApplication::sendEvent(dropWidget, &de);

                    dnd_data.reason = DND_DROP_SITE_ENTER;
                    dnd_data.time = X11->time;
                    if (de.isAccepted()) {
                        lastAcceptedAction = de.dropAction();

                        dnd_data.status = DND_VALID_DROP_SITE;
                        dnd_data.operation = QtDropActionToDndOperation(lastAcceptedAction);
                    } else {
                        dnd_data.status = DND_INVALID_DROP_SITE;
                        dnd_data.operation = DND_NOOP;
                        dnd_data.operations = DND_NOOP;
                    }
                    DndFillClientMessage (event.xclient.display, sourceWindow, &cm, &dnd_data, receiver);
                    XSendEvent(event.xbutton.display, sourceWindow, False, 0, (XEvent *)&cm);
                } else {
                    const Qt::DropActions possibleActions =
                        DndOperationsToQtDropActions(dnd_data.operations);
                    QDragMoveEvent me(p, possibleActions, QDragManager::self()->dropData,
                                      QApplication::mouseButtons(), QApplication::keyboardModifiers());
                    if (lastAcceptedAction != Qt::IgnoreAction) {
                        me.setDropAction(lastAcceptedAction);
                        me.accept();
                    }
                    QApplication::sendEvent(dropWidget, &me);

                    dnd_data.reason = DND_DRAG_MOTION;
                    dnd_data.time = X11->time;

                    if (me.isAccepted()) {
                        lastAcceptedAction = me.dropAction();

                        dnd_data.status = DND_VALID_DROP_SITE;
                        dnd_data.operation = QtDropActionToDndOperation(lastAcceptedAction);
                    } else {
                        dnd_data.status = DND_INVALID_DROP_SITE;
                        dnd_data.operation = DND_NOOP;
                        dnd_data.operations = DND_NOOP;
                    }

                    DndFillClientMessage (event.xclient.display, sourceWindow, &cm, &dnd_data, receiver);
                    XSendEvent(event.xbutton.display, sourceWindow, False, 0, (XEvent *)&cm);
                }
            }

            break;
        }

    case DND_TOP_LEVEL_ENTER:
        {
            /* get the size of our drop site for later use */

            motifdnd_active = true;
            sourceWindow = dnd_data.src_window;

            /* no answer needed, just read source property */
            DndReadSourceProperty (event.xclient.display,
                                   sourceWindow,
                                   dnd_data.property,
                                   &src_targets, &num_src_targets);

            break;
        }

    case DND_TOP_LEVEL_LEAVE:
        {
            XEvent nextEvent;
            if (XCheckTypedWindowEvent(X11->display, widget->winId(), ClientMessage, &nextEvent)) {
                // we just want to check, not eat (should use XPeekIfEvent)
                XPutBackEvent(X11->display, &nextEvent);

                if (DndParseClientMessage (&nextEvent.xclient, &dnd_data, &receiver)
                    && dnd_data.reason == DND_DROP_START) {
                    // expecting drop next, keeping DnD alive
                    break;
                }
            }

            // not expecting drop, need to send drag leave events and such here
            if (dropWidget) {
                QDragLeaveEvent le;
                QApplication::sendEvent(dropWidget, &le);
            }

            sourceWindow = XNone;
            dropWidget = 0;
            lastAcceptedAction = Qt::IgnoreAction;

            motifdnd_active = false;

            break;
        }

    case DND_OPERATION_CHANGED:
        // ### need to echo
        break;

    case DND_DROP_START:
        {
            Q_ASSERT(motifdnd_active);
            Q_ASSERT(sourceWindow == dnd_data.src_window);

            if (!dropWidget || lastAcceptedAction == Qt::IgnoreAction) {
                // echo DROP_START
                dnd_data.reason = DND_DROP_START;
                dnd_data.status = DND_NO_DROP_SITE;
                dnd_data.operation = DND_NOOP;
                dnd_data.operations = DND_NOOP;
                DndFillClientMessage (event.xclient.display, sourceWindow, &cm, &dnd_data, 0);
                XSendEvent(event.xbutton.display, sourceWindow, False, 0, (XEvent *)&cm);

                // we have to convert selection in order to indicate failure to the initiator
                XConvertSelection (X11->display, dnd_data.property, ATOM(XmTRANSFER_FAILURE),
                                   dnd_data.property, dnd_data.src_window, dnd_data.time);

                if (dropWidget) {
                    QDragLeaveEvent e;
                    QApplication::sendEvent(dropWidget, &e);
                }

                motifdnd_active = false;
                sourceWindow = XNone;
                dropWidget = 0;
                lastAcceptedAction = Qt::IgnoreAction;

                return;
            }

            // store selection and its time
            Dnd_selection = dnd_data.property;
            Dnd_selection_time = dnd_data.time;

            QPoint p(dnd_data.x, dnd_data.y);
            QDropEvent de(dropWidget->mapFromGlobal(p), Qt::CopyAction, QDragManager::self()->dropData,
                          QApplication::mouseButtons(), QApplication::keyboardModifiers());
            if (lastAcceptedAction != Qt::IgnoreAction) {
                de.setDropAction(lastAcceptedAction);
                de.accept();
            }
            QApplication::sendEvent(dropWidget, &de);

            // reset
            Dnd_selection = XNone;
            Dnd_selection_time = 0;

            // echo DROP_START depending on the result of the dropEvent
            if (de.isAccepted()) {
                dnd_data.reason = DND_DROP_START;
                dnd_data.status = DND_VALID_DROP_SITE;
                dnd_data.operation = QtDropActionToDndOperation(de.dropAction());
            } else {
                dnd_data.reason = DND_DROP_START;
                dnd_data.status = DND_NO_DROP_SITE;
                dnd_data.operation = DND_NOOP;
                dnd_data.operations = DND_NOOP;
            }
            DndFillClientMessage (event.xclient.display, sourceWindow, &cm, &dnd_data, 0);
            XSendEvent(event.xbutton.display, sourceWindow, False, 0, (XEvent *)&cm);

            sourceWindow = XNone;
            dropWidget = 0;
            lastAcceptedAction = Qt::IgnoreAction;

            motifdnd_active = false;

            break;
        }

    default:
        break;
    }   //  end of switch (dnd_data.reason)
}

QT_END_NAMESPACE

#endif // QT_NO_DRAGANDDROP