summaryrefslogtreecommitdiffstats
path: root/widget/cocoa/nsDragService.mm
blob: c4d8e6ff066bc642eff0a14866a1d3dde6d76a21 (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
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
/* -*- 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 "mozilla/Logging.h"

#include "nsArrayUtils.h"
#include "nsDragService.h"
#include "nsArrayUtils.h"
#include "nsObjCExceptions.h"
#include "nsITransferable.h"
#include "nsString.h"
#include "nsClipboard.h"
#include "nsXPCOM.h"
#include "nsISupportsPrimitives.h"
#include "nsCOMPtr.h"
#include "nsPrimitiveHelpers.h"
#include "nsLinebreakConverter.h"
#include "nsIMacUtils.h"
#include "nsIDOMNode.h"
#include "nsRect.h"
#include "nsPoint.h"
#include "nsIIOService.h"
#include "nsIDocument.h"
#include "nsIContent.h"
#include "nsView.h"
#include "gfxContext.h"
#include "nsCocoaUtils.h"
#include "mozilla/gfx/2D.h"
#include "gfxPlatform.h"

using namespace mozilla;
using namespace mozilla::gfx;

extern PRLogModuleInfo* sCocoaLog;

extern void EnsureLogInitialized();

extern NSPasteboard* globalDragPboard;
extern NSView* gLastDragView;
extern NSEvent* gLastDragMouseDownEvent;
extern bool gUserCancelledDrag;

// This global makes the transferable array available to Cocoa's promised
// file destination callback.
nsIArray *gDraggedTransferables = nullptr;

NSString* const kWildcardPboardType = @"MozillaWildcard";
NSString* const kCorePboardType_url  = @"CorePasteboardFlavorType 0x75726C20"; // 'url '  url
NSString* const kCorePboardType_urld = @"CorePasteboardFlavorType 0x75726C64"; // 'urld'  desc
NSString* const kCorePboardType_urln = @"CorePasteboardFlavorType 0x75726C6E"; // 'urln'  title
NSString* const kUTTypeURLName = @"public.url-name";
NSString* const kCustomTypesPboardType = @"org.mozilla.custom-clipdata";

nsDragService::nsDragService()
{
  mNativeDragView = nil;
  mNativeDragEvent = nil;

  EnsureLogInitialized();
}

nsDragService::~nsDragService()
{
}

static nsresult SetUpDragClipboard(nsIArray* aTransferableArray)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  if (!aTransferableArray)
    return NS_ERROR_FAILURE;

  uint32_t count = 0;
  aTransferableArray->GetLength(&count);

  NSPasteboard* dragPBoard = [NSPasteboard pasteboardWithName:NSDragPboard];

  for (uint32_t j = 0; j < count; j++) {
    nsCOMPtr<nsITransferable> currentTransferable = do_QueryElementAt(aTransferableArray, j);
    if (!currentTransferable)
      return NS_ERROR_FAILURE;

    // Transform the transferable to an NSDictionary
    NSDictionary* pasteboardOutputDict = nsClipboard::PasteboardDictFromTransferable(currentTransferable);
    if (!pasteboardOutputDict)
      return NS_ERROR_FAILURE;

    // write everything out to the general pasteboard
    unsigned int typeCount = [pasteboardOutputDict count];
    NSMutableArray* types = [NSMutableArray arrayWithCapacity:typeCount + 1];
    [types addObjectsFromArray:[pasteboardOutputDict allKeys]];
    // Gecko is initiating this drag so we always want its own views to consider
    // it. Add our wildcard type to the pasteboard to accomplish this.
    [types addObject:kWildcardPboardType]; // we don't increase the count for the loop below on purpose
    [dragPBoard declareTypes:types owner:nil];
    for (unsigned int k = 0; k < typeCount; k++) {
      NSString* currentKey = [types objectAtIndex:k];
      id currentValue = [pasteboardOutputDict valueForKey:currentKey];
      if (currentKey == NSStringPboardType ||
          currentKey == kCorePboardType_url ||
          currentKey == kCorePboardType_urld ||
          currentKey == kCorePboardType_urln) {
        [dragPBoard setString:currentValue forType:currentKey];
      }
      else if (currentKey == NSHTMLPboardType) {
        [dragPBoard setString:(nsClipboard::WrapHtmlForSystemPasteboard(currentValue))
                      forType:currentKey];
      }
      else if (currentKey == NSTIFFPboardType ||
               currentKey == kCustomTypesPboardType) {
        [dragPBoard setData:currentValue forType:currentKey];
      }
      else if (currentKey == NSFilesPromisePboardType ||
               currentKey == NSFilenamesPboardType) {
        [dragPBoard setPropertyList:currentValue forType:currentKey];        
      }
    }
  }

  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

NSImage*
nsDragService::ConstructDragImage(nsIDOMNode* aDOMNode,
                                  LayoutDeviceIntRect* aDragRect,
                                  nsIScriptableRegion* aRegion)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NIL;

  CGFloat scaleFactor = nsCocoaUtils::GetBackingScaleFactor(gLastDragView);

  RefPtr<SourceSurface> surface;
  nsPresContext* pc;
  nsresult rv = DrawDrag(aDOMNode, aRegion, mScreenPosition,
                         aDragRect, &surface, &pc);
  if (pc && (!aDragRect->width || !aDragRect->height)) {
    // just use some suitable defaults
    int32_t size = nsCocoaUtils::CocoaPointsToDevPixels(20, scaleFactor);
    aDragRect->SetRect(pc->CSSPixelsToDevPixels(mScreenPosition.x),
                       pc->CSSPixelsToDevPixels(mScreenPosition.y), size, size);
  }

  if (NS_FAILED(rv) || !surface)
    return nil;

  uint32_t width = aDragRect->width;
  uint32_t height = aDragRect->height;

  RefPtr<DataSourceSurface> dataSurface =
    Factory::CreateDataSourceSurface(IntSize(width, height),
                                     SurfaceFormat::B8G8R8A8);
  DataSourceSurface::MappedSurface map;
  if (!dataSurface->Map(DataSourceSurface::MapType::READ_WRITE, &map)) {
    return nil;
  }

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

  dt->FillRect(gfx::Rect(0, 0, width, height),
               SurfacePattern(surface, ExtendMode::CLAMP),
               DrawOptions(1.0f, CompositionOp::OP_SOURCE));

  NSBitmapImageRep* imageRep =
    [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL
                                            pixelsWide:width
                                            pixelsHigh:height
                                         bitsPerSample:8
                                       samplesPerPixel:4
                                              hasAlpha:YES
                                              isPlanar:NO
                                        colorSpaceName:NSDeviceRGBColorSpace
                                           bytesPerRow:width * 4
                                          bitsPerPixel:32];

  uint8_t* dest = [imageRep bitmapData];
  for (uint32_t i = 0; i < height; ++i) {
    uint8_t* src = map.mData + i * map.mStride;
    for (uint32_t j = 0; j < width; ++j) {
      // Reduce transparency overall by multipying by a factor. Remember, Alpha
      // is premultipled here. Also, Quartz likes RGBA, so do that translation as well.
#ifdef IS_BIG_ENDIAN
      dest[0] = uint8_t(src[1] * DRAG_TRANSLUCENCY);
      dest[1] = uint8_t(src[2] * DRAG_TRANSLUCENCY);
      dest[2] = uint8_t(src[3] * DRAG_TRANSLUCENCY);
      dest[3] = uint8_t(src[0] * DRAG_TRANSLUCENCY);
#else
      dest[0] = uint8_t(src[2] * DRAG_TRANSLUCENCY);
      dest[1] = uint8_t(src[1] * DRAG_TRANSLUCENCY);
      dest[2] = uint8_t(src[0] * DRAG_TRANSLUCENCY);
      dest[3] = uint8_t(src[3] * DRAG_TRANSLUCENCY);
#endif
      src += 4;
      dest += 4;
    }
  }
  dataSurface->Unmap();

  NSImage* image =
    [[NSImage alloc] initWithSize:NSMakeSize(width / scaleFactor,
                                             height / scaleFactor)];
  [image addRepresentation:imageRep];
  [imageRep release];

  return [image autorelease];

  NS_OBJC_END_TRY_ABORT_BLOCK_NIL;
}

bool
nsDragService::IsValidType(NSString* availableType, bool allowFileURL)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_RETURN;

  // Prevent exposing fileURL for non-fileURL type.
  // We need URL provided by dropped webloc file, but don't need file's URL.
  // kUTTypeFileURL is returned by [NSPasteboard availableTypeFromArray:] for
  // kUTTypeURL, since it conforms to kUTTypeURL.
  if (!allowFileURL && [availableType isEqualToString:(id)kUTTypeFileURL]) {
    return false;
  }

  return true;

  NS_OBJC_END_TRY_ABORT_BLOCK_RETURN(false);
}

NSString*
nsDragService::GetStringForType(NSPasteboardItem* item, const NSString* type,
                                bool allowFileURL)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NIL;

  NSString* availableType = [item availableTypeFromArray:[NSArray arrayWithObjects:(id)type, nil]];
  if (availableType && IsValidType(availableType, allowFileURL)) {
    return [item stringForType:(id)availableType];
  }

  return nil;

  NS_OBJC_END_TRY_ABORT_BLOCK_NIL;
}

NSString*
nsDragService::GetTitleForURL(NSPasteboardItem* item)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NIL;

  NSString* name = GetStringForType(item, (const NSString*)kUTTypeURLName);
  if (name) {
    return name;
  }

  NSString* filePath = GetFilePath(item);
  if (filePath) {
    return [filePath lastPathComponent];
  }

  return nil;

  NS_OBJC_END_TRY_ABORT_BLOCK_NIL;
}

NSString*
nsDragService::GetFilePath(NSPasteboardItem* item)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NIL;

  NSString* urlString = GetStringForType(item, (const NSString*)kUTTypeFileURL, true);
  if (urlString) {
    NSURL* url = [NSURL URLWithString:urlString];
    if (url) {
      return [url path];
    }
  }

  return nil;

  NS_OBJC_END_TRY_ABORT_BLOCK_NIL;
}

// We can only invoke NSView's 'dragImage:at:offset:event:pasteboard:source:slideBack:' from
// within NSView's 'mouseDown:' or 'mouseDragged:'. Luckily 'mouseDragged' is always on the
// stack when InvokeDragSession gets called.
nsresult
nsDragService::InvokeDragSessionImpl(nsIArray* aTransferableArray,
                                     nsIScriptableRegion* aDragRgn,
                                     uint32_t aActionType)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  mDataItems = aTransferableArray;

  // put data on the clipboard
  if (NS_FAILED(SetUpDragClipboard(aTransferableArray)))
    return NS_ERROR_FAILURE;

  CGFloat scaleFactor = nsCocoaUtils::GetBackingScaleFactor(gLastDragView);

  LayoutDeviceIntRect dragRect(0, 0, 20, 20);
  NSImage* image = ConstructDragImage(mSourceNode, &dragRect, aDragRgn);
  if (!image) {
    // if no image was returned, just draw a rectangle
    NSSize size;
    size.width = nsCocoaUtils::DevPixelsToCocoaPoints(dragRect.width, scaleFactor);
    size.height = nsCocoaUtils::DevPixelsToCocoaPoints(dragRect.height, scaleFactor);
    image = [[NSImage alloc] initWithSize:size];
    [image lockFocus];
    [[NSColor grayColor] set];
    NSBezierPath* path = [NSBezierPath bezierPath];
    [path setLineWidth:2.0];
    [path moveToPoint:NSMakePoint(0, 0)];
    [path lineToPoint:NSMakePoint(0, size.height)];
    [path lineToPoint:NSMakePoint(size.width, size.height)];
    [path lineToPoint:NSMakePoint(size.width, 0)];
    [path lineToPoint:NSMakePoint(0, 0)];
    [path stroke];
    [image unlockFocus];
  }

  LayoutDeviceIntPoint pt(dragRect.x, dragRect.YMost());
  NSPoint point = nsCocoaUtils::DevPixelsToCocoaPoints(pt, scaleFactor);
  point.y = nsCocoaUtils::FlippedScreenY(point.y);

  point = nsCocoaUtils::ConvertPointFromScreen([gLastDragView window], point);
  NSPoint localPoint = [gLastDragView convertPoint:point fromView:nil];
 
  // Save the transferables away in case a promised file callback is invoked.
  gDraggedTransferables = aTransferableArray;

  nsBaseDragService::StartDragSession();
  nsBaseDragService::OpenDragPopup();

  // We need to retain the view and the event during the drag in case either gets destroyed.
  mNativeDragView = [gLastDragView retain];
  mNativeDragEvent = [gLastDragMouseDownEvent retain];

  gUserCancelledDrag = false;
  [mNativeDragView dragImage:image
                          at:localPoint
                      offset:NSZeroSize
                       event:mNativeDragEvent
                  pasteboard:[NSPasteboard pasteboardWithName:NSDragPboard]
                      source:mNativeDragView
                   slideBack:YES];
  gUserCancelledDrag = false;

  if (mDoingDrag)
    nsBaseDragService::EndDragSession(false);
  
  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

NS_IMETHODIMP
nsDragService::GetData(nsITransferable* aTransferable, uint32_t aItemIndex)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  if (!aTransferable)
    return NS_ERROR_FAILURE;

  // get flavor list that includes all acceptable flavors (including ones obtained through conversion)
  nsCOMPtr<nsIArray> flavorList;
  nsresult rv = aTransferable->FlavorsTransferableCanImport(getter_AddRefs(flavorList));
  if (NS_FAILED(rv))
    return NS_ERROR_FAILURE;

  uint32_t acceptableFlavorCount;
  flavorList->GetLength(&acceptableFlavorCount);

  // if this drag originated within Mozilla we should just use the cached data from
  // when the drag started if possible
  if (mDataItems) {
    nsCOMPtr<nsITransferable> currentTransferable = do_QueryElementAt(mDataItems, aItemIndex);
    if (currentTransferable) {
      for (uint32_t i = 0; i < acceptableFlavorCount; i++) {
        nsCOMPtr<nsISupportsCString> currentFlavor = do_QueryElementAt(flavorList, i);
        if (!currentFlavor)
          continue;
        nsXPIDLCString flavorStr;
        currentFlavor->ToString(getter_Copies(flavorStr));

        nsCOMPtr<nsISupports> dataSupports;
        uint32_t dataSize = 0;
        rv = currentTransferable->GetTransferData(flavorStr, getter_AddRefs(dataSupports), &dataSize);
        if (NS_SUCCEEDED(rv)) {
          aTransferable->SetTransferData(flavorStr, dataSupports, dataSize);
          return NS_OK; // maybe try to fill in more types? Is there a point?
        }
      }
    }
  }

  // now check the actual clipboard for data
  for (uint32_t i = 0; i < acceptableFlavorCount; i++) {
    nsCOMPtr<nsISupportsCString> currentFlavor = do_QueryElementAt(flavorList, i);
    if (!currentFlavor)
      continue;

    nsXPIDLCString flavorStr;
    currentFlavor->ToString(getter_Copies(flavorStr));

    MOZ_LOG(sCocoaLog, LogLevel::Info, ("nsDragService::GetData: looking for clipboard data of type %s\n", flavorStr.get()));

    NSArray* droppedItems = [globalDragPboard pasteboardItems];
    if (!droppedItems) {
      continue;
    }

    uint32_t itemCount = [droppedItems count];
    if (aItemIndex >= itemCount) {
      continue;
    }

    NSPasteboardItem* item = [droppedItems objectAtIndex:aItemIndex];
    if (!item) {
      continue;
    }

    if (flavorStr.EqualsLiteral(kFileMime)) {
      NSString* filePath = GetFilePath(item);
      if (!filePath)
        continue;

      unsigned int stringLength = [filePath length];
      unsigned int dataLength = (stringLength + 1) * sizeof(char16_t); // in bytes
      char16_t* clipboardDataPtr = (char16_t*)malloc(dataLength);
      if (!clipboardDataPtr)
        return NS_ERROR_OUT_OF_MEMORY;
      [filePath getCharacters:reinterpret_cast<unichar*>(clipboardDataPtr)];
      clipboardDataPtr[stringLength] = 0; // null terminate

      nsCOMPtr<nsIFile> file;
      rv = NS_NewLocalFile(nsDependentString(clipboardDataPtr), true, getter_AddRefs(file));
      free(clipboardDataPtr);
      if (NS_FAILED(rv))
        continue;

      aTransferable->SetTransferData(flavorStr, file, dataLength);
      
      break;
    }
    else if (flavorStr.EqualsLiteral(kCustomTypesMime)) {
      NSString* availableType = [item availableTypeFromArray:[NSArray arrayWithObject:kCustomTypesPboardType]];
      if (!availableType || !IsValidType(availableType, false)) {
          continue;
      }
      NSData *pasteboardData = [item dataForType:availableType];
      if (!pasteboardData) {
        continue;
      }

      unsigned int dataLength = [pasteboardData length];
      void* clipboardDataPtr = malloc(dataLength);
      if (!clipboardDataPtr) {
        return NS_ERROR_OUT_OF_MEMORY;
      }
      [pasteboardData getBytes:clipboardDataPtr];

      nsCOMPtr<nsISupports> genericDataWrapper;
      nsPrimitiveHelpers::CreatePrimitiveForData(flavorStr, clipboardDataPtr, dataLength,
                                                 getter_AddRefs(genericDataWrapper));

      aTransferable->SetTransferData(flavorStr, genericDataWrapper, sizeof(nsIInputStream*));
      free(clipboardDataPtr);
      break;
    }

    NSString* pString = nil;
    if (flavorStr.EqualsLiteral(kUnicodeMime)) {
      pString = GetStringForType(item, (const NSString*)kUTTypeUTF8PlainText);
    } else if (flavorStr.EqualsLiteral(kHTMLMime)) {
      pString = GetStringForType(item, (const NSString*)kUTTypeHTML);
    } else if (flavorStr.EqualsLiteral(kURLMime)) {
      pString = GetStringForType(item, (const NSString*)kUTTypeURL);
      if (pString) {
        NSString* title = GetTitleForURL(item);
        if (!title) {
          title = pString;
        }
        pString = [NSString stringWithFormat:@"%@\n%@", pString, title];
      }
    } else if (flavorStr.EqualsLiteral(kURLDataMime)) {
      pString = GetStringForType(item, (const NSString*)kUTTypeURL);
    } else if (flavorStr.EqualsLiteral(kURLDescriptionMime)) {
      pString = GetTitleForURL(item);
    } else if (flavorStr.EqualsLiteral(kRTFMime)) {
      pString = GetStringForType(item, (const NSString*)kUTTypeRTF);
    }
    if (pString) {
      NSData* stringData;
      if (flavorStr.EqualsLiteral(kRTFMime)) {
        stringData = [pString dataUsingEncoding:NSASCIIStringEncoding];
      } else {
        stringData = [pString dataUsingEncoding:NSUnicodeStringEncoding];
      }
      unsigned int dataLength = [stringData length];
      void* clipboardDataPtr = malloc(dataLength);
      if (!clipboardDataPtr)
        return NS_ERROR_OUT_OF_MEMORY;
      [stringData getBytes:clipboardDataPtr];

      // The DOM only wants LF, so convert from MacOS line endings to DOM line endings.
      int32_t signedDataLength = dataLength;
      nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(flavorStr, &clipboardDataPtr, &signedDataLength);
      dataLength = signedDataLength;

      // skip BOM (Byte Order Mark to distinguish little or big endian)      
      char16_t* clipboardDataPtrNoBOM = (char16_t*)clipboardDataPtr;
      if ((dataLength > 2) &&
          ((clipboardDataPtrNoBOM[0] == 0xFEFF) ||
           (clipboardDataPtrNoBOM[0] == 0xFFFE))) {
        dataLength -= sizeof(char16_t);
        clipboardDataPtrNoBOM += 1;
      }

      nsCOMPtr<nsISupports> genericDataWrapper;
      nsPrimitiveHelpers::CreatePrimitiveForData(flavorStr, clipboardDataPtrNoBOM, dataLength,
                                                 getter_AddRefs(genericDataWrapper));
      aTransferable->SetTransferData(flavorStr, genericDataWrapper, dataLength);
      free(clipboardDataPtr);
      break;
    }

    // We have never supported this on Mac OS X, we should someday. Normally dragging images
    // in is accomplished with a file path drag instead of the image data itself.
    /*
    if (flavorStr.EqualsLiteral(kPNGImageMime) || flavorStr.EqualsLiteral(kJPEGImageMime) ||
        flavorStr.EqualsLiteral(kJPGImageMime) || flavorStr.EqualsLiteral(kGIFImageMime)) {

    }
    */
  }
  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

NS_IMETHODIMP
nsDragService::IsDataFlavorSupported(const char *aDataFlavor, bool *_retval)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  *_retval = false;

  if (!globalDragPboard)
    return NS_ERROR_FAILURE;

  nsDependentCString dataFlavor(aDataFlavor);

  // first see if we have data for this in our cached transferable
  if (mDataItems) {
    uint32_t dataItemsCount;
    mDataItems->GetLength(&dataItemsCount);
    for (unsigned int i = 0; i < dataItemsCount; i++) {
      nsCOMPtr<nsITransferable> currentTransferable = do_QueryElementAt(mDataItems, i);
      if (!currentTransferable)
        continue;

      nsCOMPtr<nsIArray> flavorList;
      nsresult rv = currentTransferable->FlavorsTransferableCanImport(getter_AddRefs(flavorList));
      if (NS_FAILED(rv))
        continue;

      uint32_t flavorCount;
      flavorList->GetLength(&flavorCount);
      for (uint32_t j = 0; j < flavorCount; j++) {
        nsCOMPtr<nsISupportsCString> currentFlavor = do_QueryElementAt(flavorList, j);
        if (!currentFlavor)
          continue;
        nsXPIDLCString flavorStr;
        currentFlavor->ToString(getter_Copies(flavorStr));
        if (dataFlavor.Equals(flavorStr)) {
          *_retval = true;
          return NS_OK;
        }
      }
    }
  }

  const NSString* type = nil;
  bool allowFileURL = false;
  if (dataFlavor.EqualsLiteral(kFileMime)) {
    type = (const NSString*)kUTTypeFileURL;
    allowFileURL = true;
  } else if (dataFlavor.EqualsLiteral(kUnicodeMime)) {
    type = (const NSString*)kUTTypeUTF8PlainText;
  } else if (dataFlavor.EqualsLiteral(kHTMLMime)) {
    type = (const NSString*)kUTTypeHTML;
  } else if (dataFlavor.EqualsLiteral(kURLMime) ||
             dataFlavor.EqualsLiteral(kURLDataMime)) {
    type = (const NSString*)kUTTypeURL;
  } else if (dataFlavor.EqualsLiteral(kURLDescriptionMime)) {
    type = (const NSString*)kUTTypeURLName;
  } else if (dataFlavor.EqualsLiteral(kRTFMime)) {
    type = (const NSString*)kUTTypeRTF;
  } else if (dataFlavor.EqualsLiteral(kCustomTypesMime)) {
    type = (const NSString*)kCustomTypesPboardType;
  }

  NSString* availableType = [globalDragPboard availableTypeFromArray:[NSArray arrayWithObjects:(id)type, nil]];
  if (availableType && IsValidType(availableType, allowFileURL)) {
    *_retval = true;
  }

  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

NS_IMETHODIMP
nsDragService::GetNumDropItems(uint32_t* aNumItems)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  *aNumItems = 0;

  // first check to see if we have a number of items cached
  if (mDataItems) {
    mDataItems->GetLength(aNumItems);
    return NS_OK;
  }

  NSArray* droppedItems = [globalDragPboard pasteboardItems];
  if (droppedItems) {
    *aNumItems = [droppedItems count];
  }

  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

NS_IMETHODIMP
nsDragService::EndDragSession(bool aDoneDrag)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  if (mNativeDragView) {
    [mNativeDragView release];
    mNativeDragView = nil;
  }
  if (mNativeDragEvent) {
    [mNativeDragEvent release];
    mNativeDragEvent = nil;
  }

  mUserCancelled = gUserCancelledDrag;

  nsresult rv = nsBaseDragService::EndDragSession(aDoneDrag);
  mDataItems = nullptr;
  return rv;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}