summaryrefslogtreecommitdiffstats
path: root/dom/base/DOMIntersectionObserver.cpp
blob: 0834bc05c943c09c33166975233cf4401979fc59 (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
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "DOMIntersectionObserver.h"
#include "nsCSSParser.h"
#include "nsCSSPropertyID.h"
#include "nsIFrame.h"
#include "nsContentUtils.h"
#include "nsLayoutUtils.h"

namespace mozilla {
namespace dom {

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMIntersectionObserverEntry)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMIntersectionObserverEntry)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMIntersectionObserverEntry)

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DOMIntersectionObserverEntry, mOwner,
                                      mRootBounds, mBoundingClientRect,
                                      mIntersectionRect, mTarget)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMIntersectionObserver)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
  NS_INTERFACE_MAP_ENTRY(DOMIntersectionObserver)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMIntersectionObserver)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMIntersectionObserver)

NS_IMPL_CYCLE_COLLECTION_CLASS(DOMIntersectionObserver)

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(DOMIntersectionObserver)
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(DOMIntersectionObserver)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  tmp->Disconnect();
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mOwner)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mCallback)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRoot)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mQueuedEntries)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(DOMIntersectionObserver)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOwner)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCallback)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRoot)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mQueuedEntries)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

already_AddRefed<DOMIntersectionObserver>
DOMIntersectionObserver::Constructor(const mozilla::dom::GlobalObject& aGlobal,
                                     mozilla::dom::IntersectionCallback& aCb,
                                     mozilla::ErrorResult& aRv)
{
  return Constructor(aGlobal, aCb, IntersectionObserverInit(), aRv);
}

already_AddRefed<DOMIntersectionObserver>
DOMIntersectionObserver::Constructor(const mozilla::dom::GlobalObject& aGlobal,
                                     mozilla::dom::IntersectionCallback& aCb,
                                     const mozilla::dom::IntersectionObserverInit& aOptions,
                                     mozilla::ErrorResult& aRv)
{
  nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(aGlobal.GetAsSupports());
  if (!window) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }
  RefPtr<DOMIntersectionObserver> observer =
    new DOMIntersectionObserver(window.forget(), aCb);

  observer->mRoot = aOptions.mRoot;

  if (!observer->SetRootMargin(aOptions.mRootMargin)) {
    aRv.ThrowDOMException(NS_ERROR_DOM_SYNTAX_ERR,
      NS_LITERAL_CSTRING("rootMargin must be specified in pixels or percent."));
    return nullptr;
  }

  if (aOptions.mThreshold.IsDoubleSequence()) {
    const mozilla::dom::Sequence<double>& thresholds = aOptions.mThreshold.GetAsDoubleSequence();
    observer->mThresholds.SetCapacity(thresholds.Length());
    for (const auto& thresh : thresholds) {
      if (thresh < 0.0 || thresh > 1.0) {
        aRv.ThrowTypeError<dom::MSG_THRESHOLD_RANGE_ERROR>();
        return nullptr;
      }
      observer->mThresholds.AppendElement(thresh);
    }
    observer->mThresholds.Sort();
  } else {
    double thresh = aOptions.mThreshold.GetAsDouble();
    if (thresh < 0.0 || thresh > 1.0) {
      aRv.ThrowTypeError<dom::MSG_THRESHOLD_RANGE_ERROR>();
      return nullptr;
    }
    observer->mThresholds.AppendElement(thresh);
  }

  return observer.forget();
}

bool
DOMIntersectionObserver::SetRootMargin(const nsAString& aString)
{
  // By not passing a CSS Loader object we make sure we don't parse in quirks
  // mode so that pixel/percent and unit-less values will be differentiated.
  nsCSSParser parser(nullptr);
  nsCSSValue value;
  if (!parser.ParseMarginString(aString, nullptr, 0, value, true)) {
    return false;
  }

  mRootMargin = value.GetRectValue();

  for (uint32_t i = 0; i < ArrayLength(nsCSSRect::sides); ++i) {
    nsCSSValue value = mRootMargin.*nsCSSRect::sides[i];
    if (!(value.IsPixelLengthUnit() || value.IsPercentLengthUnit())) {
      return false;
    }
  }

  return true;
}

void
DOMIntersectionObserver::GetRootMargin(mozilla::dom::DOMString& aRetVal)
{
  mRootMargin.AppendToString(eCSSProperty_DOM, aRetVal, nsCSSValue::eNormalized);
}

void
DOMIntersectionObserver::GetThresholds(nsTArray<double>& aRetVal)
{
  aRetVal = mThresholds;
}

void
DOMIntersectionObserver::Observe(Element& aTarget)
{
  if (mObservationTargets.Contains(&aTarget)) {
    return;
  }
  aTarget.RegisterIntersectionObserver(this);
  mObservationTargets.PutEntry(&aTarget);
  Connect();
}

void
DOMIntersectionObserver::Unobserve(Element& aTarget)
{
  if (UnlinkTarget(aTarget)) {
    aTarget.UnregisterIntersectionObserver(this);
  }
}

bool
DOMIntersectionObserver::UnlinkTarget(Element& aTarget)
{
    if (!mObservationTargets.Contains(&aTarget)) {
        return false;
    }
    if (mObservationTargets.Count() == 1) {
        Disconnect();
        return false;
    }
    mObservationTargets.RemoveEntry(&aTarget);
    return true;
}

void
DOMIntersectionObserver::Connect()
{
  if (mConnected) {
    return;
  }
  
  mConnected = true;
  if(mDocument) {
    mDocument->AddIntersectionObserver(this);
  }
}

void
DOMIntersectionObserver::Disconnect()
{
  if (!mConnected) {
    return;
  }
  for (auto iter = mObservationTargets.Iter(); !iter.Done(); iter.Next()) {
    Element* target = iter.Get()->GetKey();
    target->UnregisterIntersectionObserver(this);
  }
  mObservationTargets.Clear();
  if (mDocument) {
    mDocument->RemoveIntersectionObserver(this);
  }
  mConnected = false;
}

void
DOMIntersectionObserver::TakeRecords(nsTArray<RefPtr<DOMIntersectionObserverEntry>>& aRetVal)
{
  aRetVal.SwapElements(mQueuedEntries);
  mQueuedEntries.Clear();
}

static bool
CheckSimilarOrigin(nsINode* aNode1, nsINode* aNode2)
{
  nsIPrincipal* principal1 = aNode1->NodePrincipal();
  nsIPrincipal* principal2 = aNode2->NodePrincipal();
  nsAutoCString baseDomain1;
  nsAutoCString baseDomain2;

  nsresult rv = principal1->GetBaseDomain(baseDomain1);
  if (NS_FAILED(rv)) {
    return principal1 == principal2;
  }

  rv = principal2->GetBaseDomain(baseDomain2);
  if (NS_FAILED(rv)) {
    return principal1 == principal2;
  }

  return baseDomain1 == baseDomain2;
}

static Maybe<nsRect>
EdgeInclusiveIntersection(const nsRect& aRect, const nsRect& aOtherRect)
{
  nscoord left = std::max(aRect.x, aOtherRect.x);
  nscoord top = std::max(aRect.y, aOtherRect.y);
  nscoord right = std::min(aRect.XMost(), aOtherRect.XMost());
  nscoord bottom = std::min(aRect.YMost(), aOtherRect.YMost());
  if (left > right || top > bottom) {
    return Nothing();
  }
  return Some(nsRect(left, top, right - left, bottom - top));
}

enum class BrowsingContextInfo {
  SimilarOriginBrowsingContext,
  DifferentOriginBrowsingContext,
  UnknownBrowsingContext
};

void
DOMIntersectionObserver::Update(nsIDocument* aDocument, DOMHighResTimeStamp time)
{
  Element* root = nullptr;
  nsIFrame* rootFrame = nullptr;
  nsRect rootRect;

  if (mRoot) {
    root = mRoot;
    rootFrame = root->GetPrimaryFrame();
    if (rootFrame) {
      if (rootFrame->GetType() == nsGkAtoms::scrollFrame) {
        nsIScrollableFrame* scrollFrame = do_QueryFrame(rootFrame);
        rootRect = nsLayoutUtils::TransformFrameRectToAncestor(
          rootFrame,
          rootFrame->GetContentRectRelativeToSelf(),
          scrollFrame->GetScrolledFrame());
      } else {
        rootRect = nsLayoutUtils::GetAllInFlowRectsUnion(rootFrame,
          nsLayoutUtils::GetContainingBlockForClientRect(rootFrame),
          nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS);
      }
    }
  } else {
    nsCOMPtr<nsIPresShell> presShell = aDocument->GetShell();
    if (presShell) {
      rootFrame = presShell->GetRootScrollFrame();
      if (rootFrame) {
        nsPresContext* presContext = rootFrame->PresContext();
        while (!presContext->IsRootContentDocument()) {
          presContext = rootFrame->PresContext()->GetParentPresContext();
          rootFrame = presContext->PresShell()->GetRootScrollFrame();
        }
        root = rootFrame->GetContent()->AsElement();
        nsIScrollableFrame* scrollFrame = do_QueryFrame(rootFrame);
        rootRect = scrollFrame->GetScrollPortRect();
      }
    }
  }

  nsMargin rootMargin;
  NS_FOR_CSS_SIDES(side) {
    nscoord basis = side == NS_SIDE_TOP || side == NS_SIDE_BOTTOM ?
      rootRect.height : rootRect.width;
    nsCSSValue value = mRootMargin.*nsCSSRect::sides[side];
    nsStyleCoord coord;
    if (value.IsPixelLengthUnit()) {
      coord.SetCoordValue(value.GetPixelLength());
    } else if (value.IsPercentLengthUnit()) {
      coord.SetPercentValue(value.GetPercentValue());
    } else {
      MOZ_ASSERT_UNREACHABLE("invalid length unit");
    }
    rootMargin.Side(side) = nsLayoutUtils::ComputeCBDependentValue(basis, coord);
  }

  for (auto iter = mObservationTargets.Iter(); !iter.Done(); iter.Next()) {
    Element* target = iter.Get()->GetKey();
    nsIFrame* targetFrame = target->GetPrimaryFrame();
    nsRect targetRect;
    Maybe<nsRect> intersectionRect;

    if (rootFrame && targetFrame) {
      // If mRoot is set we are testing intersection with a container element
      // instead of the implicit root.
      if (mRoot) {
        // Skip further processing of this target if it is not in the same
        // Document as the intersection root, e.g. if root is an element of
        // the main document and target an element from an embedded iframe.
        if (target->GetComposedDoc() != root->GetComposedDoc()) {
          continue;
        }
        // Skip further processing of this target if is not a descendant of the
        // intersection root in the containing block chain. E.g. this would be
        // the case if the target is in a position:absolute element whose
        // containing block is an ancestor of root.
        if (!nsLayoutUtils::IsAncestorFrameCrossDoc(rootFrame, targetFrame)) {
          continue;
        }
      }

      targetRect = nsLayoutUtils::GetAllInFlowRectsUnion(
        targetFrame,
        nsLayoutUtils::GetContainingBlockForClientRect(targetFrame),
        nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS
      );
      intersectionRect = Some(targetFrame->GetVisualOverflowRect());

      nsIFrame* containerFrame = nsLayoutUtils::GetCrossDocParentFrame(targetFrame);
      while (containerFrame && containerFrame != rootFrame) {
        if (containerFrame->GetType() == nsGkAtoms::scrollFrame) {
          nsIScrollableFrame* scrollFrame = do_QueryFrame(containerFrame);
          nsRect subFrameRect = scrollFrame->GetScrollPortRect();
          nsRect intersectionRectRelativeToContainer =
            nsLayoutUtils::TransformFrameRectToAncestor(targetFrame,
                                                        intersectionRect.value(),
                                                        containerFrame);
          intersectionRect = EdgeInclusiveIntersection(intersectionRectRelativeToContainer,
                                                       subFrameRect);
          if (!intersectionRect) {
            break;
          }
          targetFrame = containerFrame;
        }

        // TODO: Apply clip-path.

        containerFrame = nsLayoutUtils::GetCrossDocParentFrame(containerFrame);
      }
    }

    nsRect rootIntersectionRect;
    BrowsingContextInfo isInSimilarOriginBrowsingContext =
      BrowsingContextInfo::UnknownBrowsingContext;

    if (rootFrame && targetFrame) {
      rootIntersectionRect = rootRect;
    }
 
    if (root && target) {
      isInSimilarOriginBrowsingContext = CheckSimilarOrigin(root, target) ?
        BrowsingContextInfo::SimilarOriginBrowsingContext :
        BrowsingContextInfo::DifferentOriginBrowsingContext;
    }

    if (isInSimilarOriginBrowsingContext ==
        BrowsingContextInfo::SimilarOriginBrowsingContext) {
      rootIntersectionRect.Inflate(rootMargin);
    }

    if (intersectionRect.isSome()) {
      nsRect intersectionRectRelativeToRoot =
        nsLayoutUtils::TransformFrameRectToAncestor(
          targetFrame,
          intersectionRect.value(),
          nsLayoutUtils::GetContainingBlockForClientRect(rootFrame)
      );
      intersectionRect = EdgeInclusiveIntersection(
        intersectionRectRelativeToRoot,
        rootIntersectionRect
      );
      if (intersectionRect.isSome()) {
        intersectionRect = Some(nsLayoutUtils::TransformFrameRectToAncestor(
          nsLayoutUtils::GetContainingBlockForClientRect(rootFrame),
          intersectionRect.value(),
          targetFrame->PresContext()->PresShell()->GetRootScrollFrame()
        ));
      }
    }

    double targetArea = targetRect.width * targetRect.height;
    double intersectionArea = !intersectionRect ?
      0 : intersectionRect->width * intersectionRect->height;
    
    double intersectionRatio;
    if (targetArea > 0.0) {
      intersectionRatio = intersectionArea / targetArea;
    } else {
      intersectionRatio = intersectionRect.isSome() ? 1.0 : 0.0;
    }

    size_t threshold = -1;
    if (intersectionRatio > 0.0) {
      if (intersectionRatio >= 1.0) {
        intersectionRatio = 1.0;
        threshold = mThresholds.Length();
      } else {
        for (size_t k = 0; k < mThresholds.Length(); ++k) {
          if (mThresholds[k] <= intersectionRatio) {
            threshold = k + 1;
          } else {
            break;
          }
        }
      }
    } else if (intersectionRect.isSome()) {
      threshold = 0;
    }

    if (target->UpdateIntersectionObservation(this, threshold)) {
      QueueIntersectionObserverEntry(
        target, time,
        isInSimilarOriginBrowsingContext ==
          BrowsingContextInfo::DifferentOriginBrowsingContext ?
          Nothing() : Some(rootIntersectionRect),
        targetRect, intersectionRect, intersectionRatio
      );
    }
  }
}

void
DOMIntersectionObserver::QueueIntersectionObserverEntry(Element* aTarget,
                                                        DOMHighResTimeStamp time,
                                                        const Maybe<nsRect>& aRootRect,
                                                        const nsRect& aTargetRect,
                                                        const Maybe<nsRect>& aIntersectionRect,
                                                        double aIntersectionRatio)
{
  RefPtr<DOMRect> rootBounds;
  if (aRootRect.isSome()) {
    rootBounds = new DOMRect(this);
    rootBounds->SetLayoutRect(aRootRect.value());
  }
  RefPtr<DOMRect> boundingClientRect = new DOMRect(this);
  boundingClientRect->SetLayoutRect(aTargetRect);
  RefPtr<DOMRect> intersectionRect = new DOMRect(this);
  if (aIntersectionRect.isSome()) {
    intersectionRect->SetLayoutRect(aIntersectionRect.value());
  }
  RefPtr<DOMIntersectionObserverEntry> entry = new DOMIntersectionObserverEntry(
    this,
    time,
    rootBounds.forget(),
    boundingClientRect.forget(),
    intersectionRect.forget(),
    aTarget, aIntersectionRatio);
  mQueuedEntries.AppendElement(entry.forget());
}

void
DOMIntersectionObserver::Notify()
{
  if (!mQueuedEntries.Length()) {
    return;
  }
  mozilla::dom::Sequence<mozilla::OwningNonNull<DOMIntersectionObserverEntry>> entries;
  if (entries.SetCapacity(mQueuedEntries.Length(), mozilla::fallible)) {
    for (uint32_t i = 0; i < mQueuedEntries.Length(); ++i) {
      RefPtr<DOMIntersectionObserverEntry> next = mQueuedEntries[i];
      *entries.AppendElement(mozilla::fallible) = next;
    }
  }
  mQueuedEntries.Clear();
  mCallback->Call(this, entries, *this);
}


} // namespace dom
} // namespace mozilla