summaryrefslogtreecommitdiffstats
path: root/xpfe/appshell/nsWindowMediator.cpp
blob: 35ae550ae2c099fc9241c82be67c44aa0ea74f36 (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
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
/* -*- 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 "nsCOMPtr.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "nsUnicharUtils.h"
#include "nsTArray.h"
#include "nsIBaseWindow.h"
#include "nsIWidget.h"
#include "nsIDOMWindow.h"
#include "nsIObserverService.h"
#include "nsIServiceManager.h"
#include "nsISimpleEnumerator.h"
#include "nsAppShellWindowEnumerator.h"
#include "nsWindowMediator.h"
#include "nsIWindowMediatorListener.h"
#include "nsXPIDLString.h"
#include "nsGlobalWindow.h"

#include "nsIDocShell.h"
#include "nsIInterfaceRequestor.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsIXULWindow.h"

using namespace mozilla;

static bool notifyOpenWindow(nsIWindowMediatorListener *aElement, void* aData);
static bool notifyCloseWindow(nsIWindowMediatorListener *aElement, void* aData);
static bool notifyWindowTitleChange(nsIWindowMediatorListener *aElement, void* aData);

// for notifyWindowTitleChange
struct WindowTitleData {
  nsIXULWindow* mWindow;
  const char16_t *mTitle;
};

nsresult
nsWindowMediator::GetDOMWindow(nsIXULWindow* inWindow,
                               nsCOMPtr<nsPIDOMWindowOuter>& outDOMWindow)
{
  nsCOMPtr<nsIDocShell> docShell;

  outDOMWindow = nullptr;
  inWindow->GetDocShell(getter_AddRefs(docShell));
  NS_ENSURE_TRUE(docShell, NS_ERROR_FAILURE);

  outDOMWindow = docShell->GetWindow();
  return outDOMWindow ? NS_OK : NS_ERROR_FAILURE;
}

nsWindowMediator::nsWindowMediator() :
  mEnumeratorList(), mOldestWindow(nullptr), mTopmostWindow(nullptr),
  mTimeStamp(0), mSortingZOrder(false), mReady(false)
{
}

nsWindowMediator::~nsWindowMediator()
{
  while (mOldestWindow)
    UnregisterWindow(mOldestWindow);
}

nsresult nsWindowMediator::Init()
{
  nsresult rv;
  nsCOMPtr<nsIObserverService> obsSvc =
    do_GetService("@mozilla.org/observer-service;1", &rv);
  NS_ENSURE_SUCCESS(rv, rv);
  rv = obsSvc->AddObserver(this, "xpcom-shutdown", true);
  NS_ENSURE_SUCCESS(rv, rv);

  mReady = true;
  return NS_OK;
}

NS_IMETHODIMP nsWindowMediator::RegisterWindow(nsIXULWindow* inWindow)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_STATE(mReady);

  if (GetInfoFor(inWindow)) {
    NS_ERROR("multiple window registration");
    return NS_ERROR_FAILURE;
  }

  mTimeStamp++;

  // Create window info struct and add to list of windows
  nsWindowInfo* windowInfo = new nsWindowInfo(inWindow, mTimeStamp);

  WindowTitleData winData = { inWindow, nullptr };
  mListeners.EnumerateForwards(notifyOpenWindow, &winData);
  
  if (mOldestWindow)
    windowInfo->InsertAfter(mOldestWindow->mOlder, nullptr);
  else
    mOldestWindow = windowInfo;

  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::UnregisterWindow(nsIXULWindow* inWindow)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_STATE(mReady);
  nsWindowInfo *info = GetInfoFor(inWindow);
  if (info)
    return UnregisterWindow(info);
  return NS_ERROR_INVALID_ARG;
}

nsresult
nsWindowMediator::UnregisterWindow(nsWindowInfo *inInfo)
{
  // Inform the iterators
  uint32_t index = 0;
  while (index < mEnumeratorList.Length()) {
    mEnumeratorList[index]->WindowRemoved(inInfo);
    index++;
  }
  
  WindowTitleData winData = { inInfo->mWindow.get(), nullptr };
  mListeners.EnumerateForwards(notifyCloseWindow, &winData);

  // Remove from the lists and free up 
  if (inInfo == mOldestWindow)
    mOldestWindow = inInfo->mYounger;
  if (inInfo == mTopmostWindow)
    mTopmostWindow = inInfo->mLower;
  inInfo->Unlink(true, true);
  if (inInfo == mOldestWindow)
    mOldestWindow = nullptr;
  if (inInfo == mTopmostWindow)
    mTopmostWindow = nullptr;
  delete inInfo;  

  return NS_OK;
}

nsWindowInfo*
nsWindowMediator::GetInfoFor(nsIXULWindow *aWindow)
{
  nsWindowInfo *info,
               *listEnd;

  if (!aWindow)
    return nullptr;

  info = mOldestWindow;
  listEnd = nullptr;
  while (info != listEnd) {
    if (info->mWindow.get() == aWindow)
      return info;
    info = info->mYounger;
    listEnd = mOldestWindow;
  }
  return nullptr;
}

nsWindowInfo*
nsWindowMediator::GetInfoFor(nsIWidget *aWindow)
{
  nsWindowInfo *info,
               *listEnd;

  if (!aWindow)
    return nullptr;

  info = mOldestWindow;
  listEnd = nullptr;

  nsCOMPtr<nsIWidget> scanWidget;
  while (info != listEnd) {
    nsCOMPtr<nsIBaseWindow> base(do_QueryInterface(info->mWindow));
    if (base)
      base->GetMainWidget(getter_AddRefs(scanWidget));
    if (aWindow == scanWidget.get())
      return info;
    info = info->mYounger;
    listEnd = mOldestWindow;
  }
  return nullptr;
}

NS_IMETHODIMP
nsWindowMediator::GetEnumerator(const char16_t* inType, nsISimpleEnumerator** outEnumerator)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(outEnumerator);
  NS_ENSURE_STATE(mReady);

  RefPtr<nsAppShellWindowEnumerator> enumerator = new nsASDOMWindowEarlyToLateEnumerator(inType, *this);
  enumerator.forget(outEnumerator);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::GetXULWindowEnumerator(const char16_t* inType, nsISimpleEnumerator** outEnumerator)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(outEnumerator);
  NS_ENSURE_STATE(mReady);

  RefPtr<nsAppShellWindowEnumerator> enumerator = new nsASXULWindowEarlyToLateEnumerator(inType, *this);
  enumerator.forget(outEnumerator);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::GetZOrderDOMWindowEnumerator(
            const char16_t *aWindowType, bool aFrontToBack,
            nsISimpleEnumerator **_retval)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(_retval);
  NS_ENSURE_STATE(mReady);

  RefPtr<nsAppShellWindowEnumerator> enumerator;
  if (aFrontToBack)
    enumerator = new nsASDOMWindowFrontToBackEnumerator(aWindowType, *this);
  else
    enumerator = new nsASDOMWindowBackToFrontEnumerator(aWindowType, *this);

  enumerator.forget(_retval);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::GetZOrderXULWindowEnumerator(
            const char16_t *aWindowType, bool aFrontToBack,
            nsISimpleEnumerator **_retval)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(_retval);
  NS_ENSURE_STATE(mReady);

  RefPtr<nsAppShellWindowEnumerator> enumerator;
  if (aFrontToBack)
    enumerator = new nsASXULWindowFrontToBackEnumerator(aWindowType, *this);
  else
    enumerator = new nsASXULWindowBackToFrontEnumerator(aWindowType, *this);

  enumerator.forget(_retval);
  return NS_OK;
}

int32_t
nsWindowMediator::AddEnumerator(nsAppShellWindowEnumerator * inEnumerator)
{
  return mEnumeratorList.AppendElement(inEnumerator) != nullptr;
}

int32_t
nsWindowMediator::RemoveEnumerator(nsAppShellWindowEnumerator * inEnumerator)
{
  return mEnumeratorList.RemoveElement(inEnumerator);
}

// Returns the window of type inType ( if null return any window type ) which has the most recent
// time stamp
NS_IMETHODIMP
nsWindowMediator::GetMostRecentWindow(const char16_t* inType,
                                      mozIDOMWindowProxy** outWindow)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(outWindow);
  *outWindow = nullptr;
  if (!mReady)
    return NS_OK;

  // Find the most window with the highest time stamp that matches
  // the requested type
  nsWindowInfo* info = MostRecentWindowInfo(inType, false);
  if (info && info->mWindow) {
    nsCOMPtr<nsPIDOMWindowOuter> DOMWindow;
    if (NS_SUCCEEDED(GetDOMWindow(info->mWindow, DOMWindow))) {  
      DOMWindow.forget(outWindow);
      return NS_OK;
    }
    return NS_ERROR_FAILURE;
  }

  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::GetMostRecentNonPBWindow(const char16_t* aType, mozIDOMWindowProxy** aWindow)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(aWindow);
  *aWindow = nullptr;

  nsWindowInfo *info = MostRecentWindowInfo(aType, true);
  nsCOMPtr<nsPIDOMWindowOuter> domWindow;
  if (info && info->mWindow) {
    GetDOMWindow(info->mWindow, domWindow);
  }

  if (!domWindow) {
    return NS_ERROR_FAILURE;
  }

  domWindow.forget(aWindow);
  return NS_OK;
}

nsWindowInfo*
nsWindowMediator::MostRecentWindowInfo(const char16_t* inType,
                                       bool aSkipPrivateBrowsingOrClosed)
{
  int32_t       lastTimeStamp = -1;
  nsAutoString  typeString(inType);
  bool          allWindows = !inType || typeString.IsEmpty();

  // Find the most recent window with the highest time stamp that matches
  // the requested type and has the correct browsing mode.
  nsWindowInfo* searchInfo = mOldestWindow;
  nsWindowInfo* listEnd = nullptr;
  nsWindowInfo* foundInfo = nullptr;
  for (; searchInfo != listEnd; searchInfo = searchInfo->mYounger) {
    listEnd = mOldestWindow;

    if (!allWindows && !searchInfo->TypeEquals(typeString)) {
      continue;
    }
    if (searchInfo->mTimeStamp < lastTimeStamp) {
      continue;
    }
    if (!searchInfo->mWindow) {
      continue;
    }
    if (aSkipPrivateBrowsingOrClosed) {
      nsCOMPtr<nsIDocShell> docShell;
      searchInfo->mWindow->GetDocShell(getter_AddRefs(docShell));
      nsCOMPtr<nsILoadContext> loadContext = do_QueryInterface(docShell);
      if (!loadContext || loadContext->UsePrivateBrowsing()) {
        continue;
      }

      nsCOMPtr<nsPIDOMWindowOuter> piwindow = docShell->GetWindow();
      if (!piwindow || piwindow->Closed()) {
        continue;
      }
    }

    foundInfo = searchInfo;
    lastTimeStamp = searchInfo->mTimeStamp;
  }

  return foundInfo;
}

NS_IMETHODIMP
nsWindowMediator::GetOuterWindowWithId(uint64_t aWindowID,
                                       mozIDOMWindowProxy** aWindow)
{
  RefPtr<nsGlobalWindow> window = nsGlobalWindow::GetOuterWindowWithId(aWindowID);
  nsCOMPtr<nsPIDOMWindowOuter> outer = window ? window->AsOuter() : nullptr;
  outer.forget(aWindow);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::GetCurrentInnerWindowWithId(uint64_t aWindowID,
                                              mozIDOMWindow** aWindow)
{
  RefPtr<nsGlobalWindow> window = nsGlobalWindow::GetInnerWindowWithId(aWindowID);

  // not found
  if (!window)
    return NS_OK;

  nsCOMPtr<nsPIDOMWindowInner> inner = window->AsInner();
  nsCOMPtr<nsPIDOMWindowOuter> outer = inner->GetOuterWindow();
  NS_ENSURE_TRUE(outer, NS_ERROR_UNEXPECTED);

  // outer is already using another inner, so it's same as not found
  if (outer->GetCurrentInnerWindow() != inner)
    return NS_OK;

  inner.forget(aWindow);
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::UpdateWindowTimeStamp(nsIXULWindow* inWindow)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_STATE(mReady);
  nsWindowInfo *info = GetInfoFor(inWindow);
  if (info) {
    // increment the window's time stamp
    info->mTimeStamp = ++mTimeStamp;
    return NS_OK;
  }
  return NS_ERROR_FAILURE; 
}

NS_IMETHODIMP
nsWindowMediator::UpdateWindowTitle(nsIXULWindow* inWindow,
                                    const char16_t* inTitle)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_STATE(mReady);
  if (GetInfoFor(inWindow)) {
    WindowTitleData winData = { inWindow, inTitle };
    mListeners.EnumerateForwards(notifyWindowTitleChange, &winData);
  }

  return NS_OK;
}

/* This method's plan is to intervene only when absolutely necessary.
   We will get requests to place our windows behind unknown windows.
   For the most part, we need to leave those alone (turning them into
   explicit requests to be on top breaks Windows.) So generally we
   calculate a change as seldom as possible.
*/
NS_IMETHODIMP
nsWindowMediator::CalculateZPosition(
                nsIXULWindow   *inWindow,
                uint32_t        inPosition,
                nsIWidget      *inBelow,
                uint32_t       *outPosition,
                nsIWidget     **outBelow,
                bool           *outAltered)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_ARG_POINTER(outBelow);
  NS_ENSURE_STATE(mReady);

  *outBelow = nullptr;

  if (!inWindow || !outPosition || !outAltered)
    return NS_ERROR_NULL_POINTER;

  if (inPosition != nsIWindowMediator::zLevelTop &&
      inPosition != nsIWindowMediator::zLevelBottom &&
      inPosition != nsIWindowMediator::zLevelBelow)
    return NS_ERROR_INVALID_ARG;

  nsWindowInfo *info = mTopmostWindow;
  nsIXULWindow *belowWindow = nullptr;
  bool          found = false;
  nsresult      result = NS_OK;

  *outPosition = inPosition;
  *outAltered = false;

  if (mSortingZOrder) { // don't fight SortZOrder()
    *outBelow = inBelow;
    NS_IF_ADDREF(*outBelow);
    return NS_OK;
  }

  uint32_t inZ;
  GetZLevel(inWindow, &inZ);

  if (inPosition == nsIWindowMediator::zLevelBelow) {
    // locate inBelow. use topmost if it can't be found or isn't in the
    // z-order list
    info = GetInfoFor(inBelow);
    if (!info || (info->mYounger != info && info->mLower == info))
      info = mTopmostWindow;
    else
      found = true;

    if (!found) {
      /* Treat unknown windows as a request to be on top.
         Not as it should be, but that's what Windows gives us.
         Note we change inPosition, but not *outPosition. This forces
         us to go through the "on top" calculation just below, without
         necessarily changing the output parameters. */
      inPosition = nsIWindowMediator::zLevelTop;
    }
  }

  if (inPosition == nsIWindowMediator::zLevelTop) {
    if (mTopmostWindow && mTopmostWindow->mZLevel > inZ) {
      // asked for topmost, can't have it. locate highest allowed position.
      do {
        if (info->mZLevel <= inZ)
          break;
        info = info->mLower;
      } while (info != mTopmostWindow);

      *outPosition = nsIWindowMediator::zLevelBelow;
      belowWindow = info->mHigher->mWindow;
      *outAltered = true;
    }
  } else if (inPosition == nsIWindowMediator::zLevelBottom) {
    if (mTopmostWindow && mTopmostWindow->mHigher->mZLevel < inZ) {
      // asked for bottommost, can't have it. locate lowest allowed position.
      do {
        info = info->mHigher;
        if (info->mZLevel >= inZ)
          break;
      } while (info != mTopmostWindow);

      *outPosition = nsIWindowMediator::zLevelBelow;
      belowWindow = info->mWindow;
      *outAltered = true;
    }
  } else {
    unsigned long relativeZ;

    // check that we're in the right z-plane
    if (found) {
      belowWindow = info->mWindow;
      relativeZ = info->mZLevel;
      if (relativeZ > inZ) {
        // might be OK. is lower window, if any, lower?
        if (info->mLower != info && info->mLower->mZLevel > inZ) {
          do {
            if (info->mZLevel <= inZ)
              break;
            info = info->mLower;
          } while (info != mTopmostWindow);

          belowWindow = info->mHigher->mWindow;
          *outAltered = true;
        }
      } else if (relativeZ < inZ) {
        // nope. look for a higher window to be behind.
        do {
          info = info->mHigher;
          if (info->mZLevel >= inZ)
            break;
        } while (info != mTopmostWindow);

        if (info->mZLevel >= inZ)
          belowWindow = info->mWindow;
        else
          *outPosition = nsIWindowMediator::zLevelTop;
        *outAltered = true;
      } // else they're equal, so it's OK
    }
  }

  if (NS_SUCCEEDED(result) && belowWindow) {
    nsCOMPtr<nsIBaseWindow> base(do_QueryInterface(belowWindow));
    if (base)
      base->GetMainWidget(outBelow);
    else
      result = NS_ERROR_NO_INTERFACE;
  }

  return result;
}

NS_IMETHODIMP
nsWindowMediator::SetZPosition(
                nsIXULWindow *inWindow,
                uint32_t      inPosition,
                nsIXULWindow *inBelow)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  nsWindowInfo *inInfo,
               *belowInfo;

  if ((inPosition != nsIWindowMediator::zLevelTop &&
       inPosition != nsIWindowMediator::zLevelBottom &&
       inPosition != nsIWindowMediator::zLevelBelow) ||
      !inWindow) {
    return NS_ERROR_INVALID_ARG;
  }

  if (mSortingZOrder) // don't fight SortZOrder()
    return NS_OK;

  NS_ENSURE_STATE(mReady);

  /* Locate inWindow and unlink it from the z-order list.
     It's important we look for it in the age list, not the z-order list.
     This is because the former is guaranteed complete, while
     now may be this window's first exposure to the latter. */
  inInfo = GetInfoFor(inWindow);
  if (!inInfo)
    return NS_ERROR_INVALID_ARG;

  // locate inBelow, place inWindow behind it
  if (inPosition == nsIWindowMediator::zLevelBelow) {
    belowInfo = GetInfoFor(inBelow);
    // it had better also be in the z-order list
    if (belowInfo &&
        belowInfo->mYounger != belowInfo && belowInfo->mLower == belowInfo) {
      belowInfo = nullptr;
    }
    if (!belowInfo) {
      if (inBelow)
        return NS_ERROR_INVALID_ARG;
      else
        inPosition = nsIWindowMediator::zLevelTop;
    }
  }
  if (inPosition == nsIWindowMediator::zLevelTop ||
      inPosition == nsIWindowMediator::zLevelBottom)
    belowInfo = mTopmostWindow ? mTopmostWindow->mHigher : nullptr;

  if (inInfo != belowInfo) {
    inInfo->Unlink(false, true);
    inInfo->InsertAfter(nullptr, belowInfo);
  }
  if (inPosition == nsIWindowMediator::zLevelTop)
    mTopmostWindow = inInfo;

  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::GetZLevel(nsIXULWindow *aWindow, uint32_t *_retval)
{
  NS_ENSURE_ARG_POINTER(_retval);
  *_retval = nsIXULWindow::normalZ;
  // This can fail during window destruction.
  nsWindowInfo *info = GetInfoFor(aWindow);
  if (info) {
    *_retval = info->mZLevel;
  }
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::SetZLevel(nsIXULWindow *aWindow, uint32_t aZLevel)
{
  MOZ_RELEASE_ASSERT(NS_IsMainThread());
  NS_ENSURE_STATE(mReady);

  nsWindowInfo *info = GetInfoFor(aWindow);
  NS_ASSERTION(info, "setting z level of unregistered window");
  if (!info)
    return NS_ERROR_FAILURE;

  if (info->mZLevel != aZLevel) {
    bool lowered = info->mZLevel > aZLevel;
    info->mZLevel = aZLevel;
    if (lowered)
      SortZOrderFrontToBack();
    else
      SortZOrderBackToFront();
  }
  return NS_OK;
}

/*   Fix potentially out-of-order windows by performing an insertion sort
   on the z-order list. The method will work no matter how broken the
   list, but its assumed usage is immediately after one window's z level
   has been changed, so one window is potentially out of place. Such a sort
   is most efficiently done in a particular direction. Use this one
   if a window's z level has just been reduced, so the sort is most efficiently
   done front to back.
     Note it's hardly worth going to all the trouble to write two versions
   of this method except that if we choose the inefficient sorting direction,
   on slow systems windows could visibly bubble around the window that
   was moved.
*/
void
nsWindowMediator::SortZOrderFrontToBack()
{
  nsWindowInfo *scan,   // scans list looking for problems
               *search, // searches for correct placement for scan window
               *prev,   // previous search element
               *lowest; // bottom-most window in list
  bool         finished;

  if (!mTopmostWindow) // early during program execution there's no z list yet
    return;            // there's also only one window, so this is not dangerous

  mSortingZOrder = true;

  /* Step through the list from top to bottom. If we find a window which
     should be moved down in the list, move it to its highest legal position. */
  do {
    finished = true;
    lowest = mTopmostWindow->mHigher;
    scan = mTopmostWindow;
    while (scan != lowest) {
      uint32_t scanZ = scan->mZLevel;
      if (scanZ < scan->mLower->mZLevel) { // out of order
        search = scan->mLower;
        do {
          prev = search;
          search = search->mLower;
        } while (prev != lowest && scanZ < search->mZLevel);

        // reposition |scan| within the list
        if (scan == mTopmostWindow)
          mTopmostWindow = scan->mLower;
        scan->Unlink(false, true);
        scan->InsertAfter(nullptr, prev);

        // fix actual window order
        nsCOMPtr<nsIBaseWindow> base;
        nsCOMPtr<nsIWidget> scanWidget;
        nsCOMPtr<nsIWidget> prevWidget;
        base = do_QueryInterface(scan->mWindow);
        if (base)
          base->GetMainWidget(getter_AddRefs(scanWidget));
        base = do_QueryInterface(prev->mWindow);
        if (base)
          base->GetMainWidget(getter_AddRefs(prevWidget));
        if (scanWidget)
          scanWidget->PlaceBehind(eZPlacementBelow, prevWidget, false);

        finished = false;
        break;
      }
      scan = scan->mLower;
    }
  } while (!finished);

  mSortingZOrder = false;
}

// see comment for SortZOrderFrontToBack
void
nsWindowMediator::SortZOrderBackToFront()
{
  nsWindowInfo *scan,   // scans list looking for problems
               *search, // searches for correct placement for scan window
               *lowest; // bottom-most window in list
  bool         finished;

  if (!mTopmostWindow) // early during program execution there's no z list yet
    return;            // there's also only one window, so this is not dangerous

  mSortingZOrder = true;

  /* Step through the list from bottom to top. If we find a window which
     should be moved up in the list, move it to its lowest legal position. */
  do {
    finished = true;
    lowest = mTopmostWindow->mHigher;
    scan = lowest;
    while (scan != mTopmostWindow) {
      uint32_t scanZ = scan->mZLevel;
      if (scanZ > scan->mHigher->mZLevel) { // out of order
        search = scan;
        do {
          search = search->mHigher;
        } while (search != lowest && scanZ > search->mZLevel);

        // reposition |scan| within the list
        if (scan != search && scan != search->mLower) {
          scan->Unlink(false, true);
          scan->InsertAfter(nullptr, search);
        }
        if (search == lowest)
          mTopmostWindow = scan;

        // fix actual window order
        nsCOMPtr<nsIBaseWindow> base;
        nsCOMPtr<nsIWidget> scanWidget;
        nsCOMPtr<nsIWidget> searchWidget;
        base = do_QueryInterface(scan->mWindow);
        if (base)
          base->GetMainWidget(getter_AddRefs(scanWidget));
        if (mTopmostWindow != scan) {
          base = do_QueryInterface(search->mWindow);
          if (base)
            base->GetMainWidget(getter_AddRefs(searchWidget));
        }
        if (scanWidget)
          scanWidget->PlaceBehind(eZPlacementBelow, searchWidget, false);
        finished = false;
        break;
      }
      scan = scan->mHigher;
    }
  } while (!finished);

  mSortingZOrder = false;
}

NS_IMPL_ISUPPORTS(nsWindowMediator,
  nsIWindowMediator_44,
  nsIWindowMediator,
  nsIObserver,
  nsISupportsWeakReference)

NS_IMETHODIMP
nsWindowMediator::AddListener(nsIWindowMediatorListener* aListener)
{
  NS_ENSURE_ARG_POINTER(aListener);
  
  mListeners.AppendObject(aListener);
  
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::RemoveListener(nsIWindowMediatorListener* aListener)
{
  NS_ENSURE_ARG_POINTER(aListener);

  mListeners.RemoveObject(aListener);
  
  return NS_OK;
}

NS_IMETHODIMP
nsWindowMediator::Observe(nsISupports* aSubject,
                          const char* aTopic,
                          const char16_t* aData)
{
  if (!strcmp(aTopic, "xpcom-shutdown") && mReady) {
    MOZ_RELEASE_ASSERT(NS_IsMainThread());
    while (mOldestWindow)
      UnregisterWindow(mOldestWindow);
    mReady = false;
  }
  return NS_OK;
}

bool
notifyOpenWindow(nsIWindowMediatorListener *aListener, void* aData)
{
  WindowTitleData* winData = static_cast<WindowTitleData*>(aData);
  aListener->OnOpenWindow(winData->mWindow);

  return true;
}

bool
notifyCloseWindow(nsIWindowMediatorListener *aListener, void* aData)
{
  WindowTitleData* winData = static_cast<WindowTitleData*>(aData);
  aListener->OnCloseWindow(winData->mWindow);

  return true;
}

bool 
notifyWindowTitleChange(nsIWindowMediatorListener *aListener, void* aData)
{
  WindowTitleData* titleData = reinterpret_cast<WindowTitleData*>(aData);
  aListener->OnWindowTitleChange(titleData->mWindow, titleData->mTitle);

  return true;
}