summaryrefslogtreecommitdiffstats
path: root/widget/windows/nsDragService.cpp
blob: 0040f550f9765ad7f92d8380278809f9420b2a01 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <ole2.h>
#include <oleidl.h>
#include <shlobj.h>
#include <shlwapi.h>

// shellapi.h is needed to build with WIN32_LEAN_AND_MEAN
#include <shellapi.h>

#include "mozilla/RefPtr.h"
#include "nsDragService.h"
#include "nsITransferable.h"
#include "nsDataObj.h"

#include "nsWidgetsCID.h"
#include "nsNativeDragTarget.h"
#include "nsNativeDragSource.h"
#include "nsClipboard.h"
#include "nsIDocument.h"
#include "nsDataObjCollection.h"

#include "nsArrayUtils.h"
#include "nsString.h"
#include "nsEscape.h"
#include "nsIScreenManager.h"
#include "nsISupportsPrimitives.h"
#include "nsIURL.h"
#include "nsCWebBrowserPersist.h"
#include "nsToolkit.h"
#include "nsCRT.h"
#include "nsDirectoryServiceDefs.h"
#include "nsUnicharUtils.h"
#include "gfxContext.h"
#include "nsRect.h"
#include "nsMathUtils.h"
#include "WinUtils.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/DataSurfaceHelpers.h"
#include "mozilla/gfx/Tools.h"

using namespace mozilla;
using namespace mozilla::gfx;

//-------------------------------------------------------------------------
//
// DragService constructor
//
//-------------------------------------------------------------------------
nsDragService::nsDragService()
  : mDataObject(nullptr), mSentLocalDropEvent(false)
{
}

//-------------------------------------------------------------------------
//
// DragService destructor
//
//-------------------------------------------------------------------------
nsDragService::~nsDragService()
{
  NS_IF_RELEASE(mDataObject);
}

bool
nsDragService::CreateDragImage(nsIDOMNode *aDOMNode,
                               nsIScriptableRegion *aRegion,
                               SHDRAGIMAGE *psdi)
{
  if (!psdi)
    return false;

  memset(psdi, 0, sizeof(SHDRAGIMAGE));
  if (!aDOMNode)
    return false;

  // Prepare the drag image
  LayoutDeviceIntRect dragRect;
  RefPtr<SourceSurface> surface;
  nsPresContext* pc;
  DrawDrag(aDOMNode, aRegion, mScreenPosition, &dragRect, &surface, &pc);
  if (!surface)
    return false;

  uint32_t bmWidth = dragRect.width, bmHeight = dragRect.height;

  if (bmWidth == 0 || bmHeight == 0)
    return false;

  psdi->crColorKey = CLR_NONE;

  RefPtr<DataSourceSurface> dataSurface =
    Factory::CreateDataSourceSurface(IntSize(bmWidth, bmHeight),
                                     SurfaceFormat::B8G8R8A8);
  NS_ENSURE_TRUE(dataSurface, false);

  DataSourceSurface::MappedSurface map;
  if (!dataSurface->Map(DataSourceSurface::MapType::READ_WRITE, &map)) {
    return false;
  }

  RefPtr<DrawTarget> dt =
    Factory::CreateDrawTargetForData(BackendType::CAIRO,
                                     map.mData,
                                     dataSurface->GetSize(),
                                     map.mStride,
                                     dataSurface->GetFormat());
  if (!dt) {
    dataSurface->Unmap();
    return false;
  }

  dt->DrawSurface(surface,
                  Rect(0, 0, dataSurface->GetSize().width, dataSurface->GetSize().height),
                  Rect(0, 0, surface->GetSize().width, surface->GetSize().height),
                  DrawSurfaceOptions(),
                  DrawOptions(1.0f, CompositionOp::OP_SOURCE));
  dt->Flush();

  BITMAPV5HEADER bmih;
  memset((void*)&bmih, 0, sizeof(BITMAPV5HEADER));
  bmih.bV5Size        = sizeof(BITMAPV5HEADER);
  bmih.bV5Width       = bmWidth;
  bmih.bV5Height      = -(int32_t)bmHeight; // flip vertical
  bmih.bV5Planes      = 1;
  bmih.bV5BitCount    = 32;
  bmih.bV5Compression = BI_BITFIELDS;
  bmih.bV5RedMask     = 0x00FF0000;
  bmih.bV5GreenMask   = 0x0000FF00;
  bmih.bV5BlueMask    = 0x000000FF;
  bmih.bV5AlphaMask   = 0xFF000000;

  HDC hdcSrc = CreateCompatibleDC(nullptr);
  void *lpBits = nullptr;
  if (hdcSrc) {
    psdi->hbmpDragImage =
    ::CreateDIBSection(hdcSrc, (BITMAPINFO*)&bmih, DIB_RGB_COLORS,
                       (void**)&lpBits, nullptr, 0);
    if (psdi->hbmpDragImage && lpBits) {
      CopySurfaceDataToPackedArray(map.mData, static_cast<uint8_t*>(lpBits),
                                   dataSurface->GetSize(), map.mStride,
                                   BytesPerPixel(dataSurface->GetFormat()));
    }

    psdi->sizeDragImage.cx = bmWidth;
    psdi->sizeDragImage.cy = bmHeight;

    LayoutDeviceIntPoint screenPoint =
      ConvertToUnscaledDevPixels(pc, mScreenPosition);
    psdi->ptOffset.x = screenPoint.x - dragRect.x;
    psdi->ptOffset.y = screenPoint.y - dragRect.y;

    DeleteDC(hdcSrc);
  }

  dataSurface->Unmap();

  return psdi->hbmpDragImage != nullptr;
}

//-------------------------------------------------------------------------
nsresult
nsDragService::InvokeDragSessionImpl(nsIArray* anArrayTransferables,
                                     nsIScriptableRegion* aRegion,
                                     uint32_t aActionType)
{
  // Try and get source URI of the items that are being dragged
  nsIURI *uri = nullptr;

  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mSourceDocument));
  if (doc) {
    uri = doc->GetDocumentURI();
  }

  uint32_t numItemsToDrag = 0;
  nsresult rv = anArrayTransferables->GetLength(&numItemsToDrag);
  if (!numItemsToDrag)
    return NS_ERROR_FAILURE;

  // The clipboard class contains some static utility methods that we
  // can use to create an IDataObject from the transferable

  // if we're dragging more than one item, we need to create a
  // "collection" object to fake out the OS. This collection contains
  // one |IDataObject| for each transferable. If there is just the one
  // (most cases), only pass around the native |IDataObject|.
  RefPtr<IDataObject> itemToDrag;
  if (numItemsToDrag > 1) {
    nsDataObjCollection * dataObjCollection = new nsDataObjCollection();
    if (!dataObjCollection)
      return NS_ERROR_OUT_OF_MEMORY;
    itemToDrag = dataObjCollection;
    for (uint32_t i=0; i<numItemsToDrag; ++i) {
      nsCOMPtr<nsITransferable> trans =
          do_QueryElementAt(anArrayTransferables, i);
      if (trans) {
        // set the requestingPrincipal on the transferable
        nsCOMPtr<nsINode> node = do_QueryInterface(mSourceNode);
        trans->SetRequestingPrincipal(node->NodePrincipal());
        trans->SetContentPolicyType(mContentPolicyType);
        RefPtr<IDataObject> dataObj;
        rv = nsClipboard::CreateNativeDataObject(trans,
                                                 getter_AddRefs(dataObj), uri);
        NS_ENSURE_SUCCESS(rv, rv);
        // Add the flavors to the collection object too
        rv = nsClipboard::SetupNativeDataObject(trans, dataObjCollection);
        NS_ENSURE_SUCCESS(rv, rv);

        dataObjCollection->AddDataObject(dataObj);
      }
    }
  } // if dragging multiple items
  else {
    nsCOMPtr<nsITransferable> trans =
        do_QueryElementAt(anArrayTransferables, 0);
    if (trans) {
      // set the requestingPrincipal on the transferable
      nsCOMPtr<nsINode> node = do_QueryInterface(mSourceNode);
      trans->SetRequestingPrincipal(node->NodePrincipal());
      trans->SetContentPolicyType(mContentPolicyType);
      rv = nsClipboard::CreateNativeDataObject(trans,
                                               getter_AddRefs(itemToDrag),
                                               uri);
      NS_ENSURE_SUCCESS(rv, rv);
    }
  } // else dragging a single object

  // Create a drag image if support is available
  IDragSourceHelper *pdsh;
  if (SUCCEEDED(CoCreateInstance(CLSID_DragDropHelper, nullptr,
                                 CLSCTX_INPROC_SERVER,
                                 IID_IDragSourceHelper, (void**)&pdsh))) {
    SHDRAGIMAGE sdi;
    if (CreateDragImage(mSourceNode, aRegion, &sdi)) {
      if (FAILED(pdsh->InitializeFromBitmap(&sdi, itemToDrag)))
        DeleteObject(sdi.hbmpDragImage);
    }
    pdsh->Release();
  }

  // Kick off the native drag session
  return StartInvokingDragSession(itemToDrag, aActionType);
}

static bool
LayoutDevicePointToCSSPoint(const LayoutDevicePoint& aDevPos,
                            CSSPoint& aCSSPos)
{
  nsCOMPtr<nsIScreenManager> screenMgr =
    do_GetService("@mozilla.org/gfx/screenmanager;1");
  if (!screenMgr) {
    return false;
  }

  nsCOMPtr<nsIScreen> screen;
  screenMgr->ScreenForRect(NSToIntRound(aDevPos.x), NSToIntRound(aDevPos.y),
                           1, 1, getter_AddRefs(screen));
  if (!screen) {
    return false;
  }

  int32_t w,h; // unused
  LayoutDeviceIntPoint screenOriginDev;
  screen->GetRect(&screenOriginDev.x, &screenOriginDev.y, &w, &h);

  double scale;
  screen->GetDefaultCSSScaleFactor(&scale);
  LayoutDeviceToCSSScale devToCSSScale =
    CSSToLayoutDeviceScale(scale).Inverse();

  // Desktop pixels and CSS pixels share the same screen origin.
  CSSIntPoint screenOriginCSS;
  screen->GetRectDisplayPix(&screenOriginCSS.x, &screenOriginCSS.y, &w, &h);

  aCSSPos = (aDevPos - screenOriginDev) * devToCSSScale + screenOriginCSS;
  return true;
}

//-------------------------------------------------------------------------
NS_IMETHODIMP
nsDragService::StartInvokingDragSession(IDataObject * aDataObj,
                                        uint32_t aActionType)
{
  // To do the drag we need to create an object that
  // implements the IDataObject interface (for OLE)
  RefPtr<nsNativeDragSource> nativeDragSrc =
    new nsNativeDragSource(mDataTransfer);

  // Now figure out what the native drag effect should be
  DWORD winDropRes;
  DWORD effects = DROPEFFECT_SCROLL;
  if (aActionType & DRAGDROP_ACTION_COPY) {
    effects |= DROPEFFECT_COPY;
  }
  if (aActionType & DRAGDROP_ACTION_MOVE) {
    effects |= DROPEFFECT_MOVE;
  }
  if (aActionType & DRAGDROP_ACTION_LINK) {
    effects |= DROPEFFECT_LINK;
  }

  // XXX not sure why we bother to cache this, it can change during
  // the drag
  mDragAction = aActionType;
  mSentLocalDropEvent = false;

  // Start dragging
  StartDragSession();
  OpenDragPopup();

  RefPtr<IAsyncOperation> pAsyncOp;
  // Offer to do an async drag
  if (SUCCEEDED(aDataObj->QueryInterface(IID_IAsyncOperation,
                                         getter_AddRefs(pAsyncOp)))) {
    pAsyncOp->SetAsyncMode(VARIANT_TRUE);
  } else {
    NS_NOTREACHED("When did our data object stop being async");
  }

  // Call the native D&D method
  HRESULT res = ::DoDragDrop(aDataObj, nativeDragSrc, effects, &winDropRes);

  // In  cases where the drop operation completed outside the application, update
  // the source node's nsIDOMDataTransfer dropEffect value so it is up to date.
  if (!mSentLocalDropEvent) {
    uint32_t dropResult;
    // Order is important, since multiple flags can be returned.
    if (winDropRes & DROPEFFECT_COPY)
        dropResult = DRAGDROP_ACTION_COPY;
    else if (winDropRes & DROPEFFECT_LINK)
        dropResult = DRAGDROP_ACTION_LINK;
    else if (winDropRes & DROPEFFECT_MOVE)
        dropResult = DRAGDROP_ACTION_MOVE;
    else
        dropResult = DRAGDROP_ACTION_NONE;

    if (mDataTransfer) {
      if (res == DRAGDROP_S_DROP) // Success
        mDataTransfer->SetDropEffectInt(dropResult);
      else
        mDataTransfer->SetDropEffectInt(DRAGDROP_ACTION_NONE);
    }
  }

  mUserCancelled = nativeDragSrc->UserCancelled();

  // We're done dragging, get the cursor position and end the drag
  // Use GetMessagePos to get the position of the mouse at the last message
  // seen by the event loop. (Bug 489729)
  // Note that we must convert this from device pixels back to Windows logical
  // pixels (bug 818927).
  DWORD pos = ::GetMessagePos();
  CSSPoint cssPos;
  if (!LayoutDevicePointToCSSPoint(LayoutDevicePoint(GET_X_LPARAM(pos),
                                                     GET_Y_LPARAM(pos)),
                                   cssPos)) {
    // fallback to the simple scaling
    POINT pt = { GET_X_LPARAM(pos), GET_Y_LPARAM(pos) };
    HMONITOR monitor = ::MonitorFromPoint(pt, MONITOR_DEFAULTTOPRIMARY);
    double dpiScale = widget::WinUtils::LogToPhysFactor(monitor);
    cssPos.x = GET_X_LPARAM(pos) / dpiScale;
    cssPos.y = GET_Y_LPARAM(pos) / dpiScale;
  }
  // We have to abuse SetDragEndPoint to pass CSS pixels because
  // Event::GetScreenCoords will not convert pixels for dragend events
  // until bug 1224754 is fixed.
  SetDragEndPoint(LayoutDeviceIntPoint(NSToIntRound(cssPos.x),
                                       NSToIntRound(cssPos.y)));
  EndDragSession(true);

  mDoingDrag = false;

  return DRAGDROP_S_DROP == res ? NS_OK : NS_ERROR_FAILURE;
}

//-------------------------------------------------------------------------
// Make Sure we have the right kind of object
nsDataObjCollection*
nsDragService::GetDataObjCollection(IDataObject* aDataObj)
{
  nsDataObjCollection * dataObjCol = nullptr;
  if (aDataObj) {
    nsIDataObjCollection* dataObj;
    if (aDataObj->QueryInterface(IID_IDataObjCollection,
                                 (void**)&dataObj) == S_OK) {
      dataObjCol = static_cast<nsDataObjCollection*>(aDataObj);
      dataObj->Release();
    }
  }

  return dataObjCol;
}

//-------------------------------------------------------------------------
NS_IMETHODIMP
nsDragService::GetNumDropItems(uint32_t * aNumItems)
{
  if (!mDataObject) {
    *aNumItems = 0;
    return NS_OK;
  }

  if (IsCollectionObject(mDataObject)) {
    nsDataObjCollection * dataObjCol = GetDataObjCollection(mDataObject);
    if (dataObjCol) {
      *aNumItems = dataObjCol->GetNumDataObjects();
    }
    else {
      // If the count cannot be determined just return 0.
      // This can happen if we have collection data of type
      // MULTI_MIME ("Mozilla/IDataObjectCollectionFormat") on the clipboard
      // from another process but we can't obtain an IID_IDataObjCollection
      // from this process.
      *aNumItems = 0;
    }
  }
  else {
    // Next check if we have a file drop. Return the number of files in
    // the file drop as the number of items we have, pretending like we
    // actually have > 1 drag item.
    FORMATETC fe2;
    SET_FORMATETC(fe2, CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
    if (mDataObject->QueryGetData(&fe2) == S_OK) {
      STGMEDIUM stm;
      if (mDataObject->GetData(&fe2, &stm) == S_OK) {
        HDROP hdrop = (HDROP)GlobalLock(stm.hGlobal);
        *aNumItems = ::DragQueryFileW(hdrop, 0xFFFFFFFF, nullptr, 0);
        ::GlobalUnlock(stm.hGlobal);
        ::ReleaseStgMedium(&stm);
        // Data may be provided later, so assume we have 1 item
        if (*aNumItems == 0)
          *aNumItems = 1;
      }
      else
        *aNumItems = 1;
    }
    else
      *aNumItems = 1;
  }

  return NS_OK;
}

//-------------------------------------------------------------------------
NS_IMETHODIMP
nsDragService::GetData(nsITransferable * aTransferable, uint32_t anItem)
{
  // This typcially happens on a drop, the target would be asking
  // for it's transferable to be filled in
  // Use a static clipboard utility method for this
  if (!mDataObject)
    return NS_ERROR_FAILURE;

  nsresult dataFound = NS_ERROR_FAILURE;

  if (IsCollectionObject(mDataObject)) {
    // multiple items, use |anItem| as an index into our collection
    nsDataObjCollection * dataObjCol = GetDataObjCollection(mDataObject);
    uint32_t cnt = dataObjCol->GetNumDataObjects();
    if (anItem < cnt) {
      IDataObject * dataObj = dataObjCol->GetDataObjectAt(anItem);
      dataFound = nsClipboard::GetDataFromDataObject(dataObj, 0, nullptr,
                                                     aTransferable);
    }
    else
      NS_WARNING("Index out of range!");
  }
  else {
    // If they are asking for item "0", we can just get it...
    if (anItem == 0) {
       dataFound = nsClipboard::GetDataFromDataObject(mDataObject, anItem,
                                                      nullptr, aTransferable);
    } else {
      // It better be a file drop, or else non-zero indexes are invalid!
      FORMATETC fe2;
      SET_FORMATETC(fe2, CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
      if (mDataObject->QueryGetData(&fe2) == S_OK)
        dataFound = nsClipboard::GetDataFromDataObject(mDataObject, anItem,
                                                       nullptr, aTransferable);
      else
        NS_WARNING("Reqesting non-zero index, but clipboard data is not a collection!");
    }
  }
  return dataFound;
}

//---------------------------------------------------------
NS_IMETHODIMP
nsDragService::SetIDataObject(IDataObject * aDataObj)
{
  // When the native drag starts the DragService gets
  // the IDataObject that is being dragged
  NS_IF_RELEASE(mDataObject);
  mDataObject = aDataObj;
  NS_IF_ADDREF(mDataObject);

  return NS_OK;
}

//---------------------------------------------------------
void
nsDragService::SetDroppedLocal()
{
  // Sent from the native drag handler, letting us know
  // a drop occurred within the application vs. outside of it.
  mSentLocalDropEvent = true;
  return;
}

//-------------------------------------------------------------------------
NS_IMETHODIMP
nsDragService::IsDataFlavorSupported(const char *aDataFlavor, bool *_retval)
{
  if (!aDataFlavor || !mDataObject || !_retval)
    return NS_ERROR_FAILURE;

#ifdef DEBUG
  if (strcmp(aDataFlavor, kTextMime) == 0)
    NS_WARNING("DO NOT USE THE text/plain DATA FLAVOR ANY MORE. USE text/unicode INSTEAD");
#endif

  *_retval = false;

  FORMATETC fe;
  UINT format = 0;

  if (IsCollectionObject(mDataObject)) {
    // We know we have one of our special collection objects.
    format = nsClipboard::GetFormat(aDataFlavor);
    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
                  TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);

    // See if any one of the IDataObjects in the collection supports
    // this data type
    nsDataObjCollection* dataObjCol = GetDataObjCollection(mDataObject);
    if (dataObjCol) {
      uint32_t cnt = dataObjCol->GetNumDataObjects();
      for (uint32_t i=0;i<cnt;++i) {
        IDataObject * dataObj = dataObjCol->GetDataObjectAt(i);
        if (S_OK == dataObj->QueryGetData(&fe))
          *_retval = true;             // found it!
      }
    }
  } // if special collection object
  else {
    // Ok, so we have a single object. Check to see if has the correct
    // data type. Since this can come from an outside app, we also
    // need to see if we need to perform text->unicode conversion if
    // the client asked for unicode and it wasn't available.
    format = nsClipboard::GetFormat(aDataFlavor);
    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
                  TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
    if (mDataObject->QueryGetData(&fe) == S_OK)
      *_retval = true;                 // found it!
    else {
      // We haven't found the exact flavor the client asked for, but
      // maybe we can still find it from something else that's on the
      // clipboard
      if (strcmp(aDataFlavor, kUnicodeMime) == 0) {
        // client asked for unicode and it wasn't present, check if we
        // have CF_TEXT.  We'll handle the actual data substitution in
        // the data object.
        format = nsClipboard::GetFormat(kTextMime);
        SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
                      TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
        if (mDataObject->QueryGetData(&fe) == S_OK)
          *_retval = true;                 // found it!
      }
      else if (strcmp(aDataFlavor, kURLMime) == 0) {
        // client asked for a url and it wasn't present, but if we
        // have a file, then we have a URL to give them (the path, or
        // the internal URL if an InternetShortcut).
        format = nsClipboard::GetFormat(kFileMime);
        SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
                      TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
        if (mDataObject->QueryGetData(&fe) == S_OK)
          *_retval = true;                 // found it!
      }
    } // else try again
  }

  return NS_OK;
}


//
// IsCollectionObject
//
// Determine if this is a single |IDataObject| or one of our private
// collection objects. We know the difference because our collection
// object will respond to supporting the private |MULTI_MIME| format.
//
bool
nsDragService::IsCollectionObject(IDataObject* inDataObj)
{
  bool isCollection = false;

  // setup the format object to ask for the MULTI_MIME format. We only
  // need to do this once
  static UINT sFormat = 0;
  static FORMATETC sFE;
  if (!sFormat) {
    sFormat = nsClipboard::GetFormat(MULTI_MIME);
    SET_FORMATETC(sFE, sFormat, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
  }

  // ask the object if it supports it. If yes, we have a collection
  // object
  if (inDataObj->QueryGetData(&sFE) == S_OK)
    isCollection = true;

  return isCollection;

} // IsCollectionObject


//
// EndDragSession
//
// Override the default to make sure that we release the data object
// when the drag ends. It seems that OLE doesn't like to let apps quit
// w/out crashing when we're still holding onto their data
//
NS_IMETHODIMP
nsDragService::EndDragSession(bool aDoneDrag)
{
  // Bug 100180: If we've got mouse events captured, make sure we release it -
  // that way, if we happen to call EndDragSession before diving into a nested
  // event loop, we can still respond to mouse events.
  if (::GetCapture()) {
    ::ReleaseCapture();
  }

  nsBaseDragService::EndDragSession(aDoneDrag);
  NS_IF_RELEASE(mDataObject);

  return NS_OK;
}