/****************************************************************************
**
** Copyright (C) 1992-2004 Trolltech AS. All rights reserved.
**
** This file is part of the gui module of the Qt Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
**   information about Qt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for QPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

/* The following copyright notice pertains to the code as contributed
to Trolltech, not to Trolltech'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 : Trolltech AS */
/***********************************************************/

#include "qplatformdefs.h"

#include "qapplication.h"

#ifndef QT_NO_DRAGANDDROP

#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>

static bool in_drop_site = false;
static Window cur_window = 0;
static QWidget *drop_widget = 0L;

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)

/* 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 int _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)
{
    DndSrcProp * src_prop = 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,
                             (unsigned char **) &src_prop) != Success)
        || (type == XNone)) {
        *num_targets = 0;
        return ;
    }

    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 thru 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 thru, 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;
    Window         *property = 0;
    Window            motif_window ;

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

    if ((XGetWindowProperty (display, DefaultRootWindow(display),
                             ATOM(_MOTIF_DRAG_WINDOW),
                             0L, 100000L, False, AnyPropertyType,
                             &type, &format, &size, &bytes_after,
                             (unsigned char **) &property) == Success) &&
        (type != XNone)) {
        motif_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,
                                      DefaultRootWindow (display),
                                      -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) ;
    DndTargets * target_prop;
    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,
                             (unsigned char **) &target_prop) != Success) ||
        type == XNone) {
        qWarning("QMotifDND: cannot get property on motif window");
        return 0;
    }

    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 int _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)) {
        return -1;
    }

    /* 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;
}


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

    if (n == 0)
        return "text/plain";
    if (n == 1)
        return "text/uri-list";
    n -= 2;

    if (n >= num_src_targets)
        return 0;

    Atom target = src_targets[n];

    Atom xa_utf8_string = ATOM(UTF8_STRING);
    Atom xa_text = ATOM(TEXT);
    Atom xa_compound_text = ATOM(COMPOUND_TEXT);

    if (target == XA_STRING)
        return "text/plain;charset=ISO-8859-1";
    if (target == xa_utf8_string)
        return "text/plain;charset=UTF-8";
    if (target == xa_text ||
         target == xa_compound_text)
        return "text/plain";

    return X11->xdndAtomToString(target);
}


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

    Q_ASSERT(Dnd_selection != 0);

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

    int n=0;
    const char* f;
    do {
        f = motifdndFormat(n);
        if (!f)
            return result;
        n++;
    } while(qstricmp(mimeType, f));

    // found one
    Atom conversion_type;

    if (qstrnicmp(f, "text/", 5) == 0) {
        // always convert text to XA_STRING for compatibility with
        // prior Qt versions
        conversion_type = XA_STRING;
    } else {
        conversion_type = X11->xdndStringToAtom(f);
        // qDebug("found format '%s' 0x%lx '%s'", f, conversion_type,
        // X11->xdndAtomToString(conversion_type));
    }

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

    QWidget* tw = drop_widget;
    if (drop_widget->isDesktop()) {
        tw = new QWidget;
    }

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

    XFlush(X11->display);

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

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

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

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

    if (drop_widget->isDesktop()) {
        delete tw;
    }

    return result;
}


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


void QX11Data::motifdndHandle(QWidget * /* w */ , 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:

        {
            /* check if in drop site, and depending on the state,
               send a drop site enter or drop site leave or echo */

            QPoint p(dnd_data.x, dnd_data.y);
            QWidget *c = QApplication::widgetAt(p);
            if (c)
                p = c->mapFromGlobal(p);

            while (c && !c->acceptDrops() && !c->isTopLevel()) {
                p = c->mapToParent(p);
                c = c->parentWidget();
            }

            QDragMoveEvent me(p, QDrag::CopyAction, QDragManager::self()->dropData);

            if (c != 0L && c->acceptDrops()) {

                if (drop_widget != 0L && drop_widget->acceptDrops() &&
                     drop_widget != c) {
                    QDragLeaveEvent e;
                    QApplication::sendEvent(drop_widget, &e);
                    QDragEnterEvent de(p, QDrag::CopyAction, QDragManager::self()->dropData);
                    QApplication::sendEvent(c, &de);
                }

                drop_widget = c;

                if (!in_drop_site) {
                    in_drop_site = True ;

                    dnd_data.reason = DND_DROP_SITE_ENTER ;
                    dnd_data.time = CurrentTime ;
                    dnd_data.operation = DND_MOVE|DND_COPY;
                    dnd_data.operations = DND_MOVE|DND_COPY;

                    DndFillClientMessage (event.xclient.display,
                                          cur_window,
                                          &cm, &dnd_data, 0);

                    XSendEvent(event.xbutton.display,
                               cur_window, False, 0,
                               (XEvent *)&cm) ;

                    QDragEnterEvent de(p, QDrag::CopyAction, QDragManager::self()->dropData);
                    QApplication::sendEvent(drop_widget, &de);
                    if (de.isAccepted()) {
                        me.accept(de.answerRect());
                    } else {
                        me.ignore(de.answerRect());
                    }

                } else {
                    dnd_data.reason = DND_DRAG_MOTION ;
                    dnd_data.time = CurrentTime ;
                    dnd_data.operation = DND_MOVE|DND_COPY;
                    dnd_data.operations = DND_MOVE|DND_COPY;

                    DndFillClientMessage (event.xclient.display,
                                          cur_window,
                                          &cm, &dnd_data, 0);

                    XSendEvent(event.xbutton.display,
                               cur_window, False, 0,
                               (XEvent *)&cm) ;

                    QApplication::sendEvent(drop_widget, &me);
                }
            } else {
                if (in_drop_site) {
                    in_drop_site = False ;

                    dnd_data.reason = DND_DROP_SITE_LEAVE ;
                    dnd_data.time = CurrentTime ;

                    DndFillClientMessage (event.xclient.display,
                                          cur_window,
                                          &cm, &dnd_data, 0);

                    XSendEvent(event.xbutton.display,
                               cur_window, False, 0,
                               (XEvent *)&cm) ;

                    QDragLeaveEvent e;
                    QApplication::sendEvent(drop_widget, &e);
                }
            }
        }
        break;

    case DND_TOP_LEVEL_ENTER:

        /* get the size of our drop site for later use */

        cur_window = dnd_data.src_window ;
        motifdnd_active = true;

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

    case DND_TOP_LEVEL_LEAVE:
        /* no need to do anything */
        break;

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

    case DND_DROP_START:
        if (!in_drop_site) {
            // 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, cur_window, dnd_data.time);

            if (drop_widget) {
                QDragLeaveEvent e;
                QApplication::sendEvent(drop_widget, &e);
                drop_widget = 0;
            }

            return;
        }

        /* need to echo and then request a convert */
        dnd_data.reason = DND_DROP_START ;

        DndFillClientMessage (event.xclient.display,
                              drop_widget->winId(),
                              &cm, &dnd_data, 0);

        XSendEvent(event.xbutton.display,
                   cur_window, False, 0,
                   (XEvent *)&cm) ;

        // 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(drop_widget->mapFromGlobal(p), QDrag::CopyAction, QDragManager::self()->dropData);
        QApplication::sendEvent(drop_widget, &de);

        if (in_drop_site)
            in_drop_site = False ;

        drop_widget = 0;
        cur_window = 0;
        break;
    }   //  end of switch (dnd_data.reason)
}

#endif // QT_NO_DRAGANDDROP
