dom/base/nsDOMMutationObserver.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsDOMMutationObserver.h"
   8
   9 #include "mozilla/AnimationTarget.h"
  10 #include "mozilla/CycleCollectedJSContext.h"
  11 #include "mozilla/Maybe.h"
  12 #include "mozilla/OwningNonNull.h"
  13
  14 #include "mozilla/dom/Animation.h"
  15 #include "mozilla/dom/KeyframeEffect.h"
  16 #include "mozilla/dom/DocGroup.h"
  17
  18 #include "mozilla/BasePrincipal.h"
  19
  20 #include "nsContentUtils.h"
  21 #include "nsCSSPseudoElements.h"
  22 #include "nsError.h"
  23 #include "nsIScriptGlobalObject.h"
  24 #include "nsNameSpaceManager.h"
  25 #include "nsServiceManagerUtils.h"
  26 #include "nsTextFragment.h"
  27 #include "nsThreadUtils.h"
  28
  29 using namespace mozilla;
  30 using namespace mozilla::dom;
  31
  32 AutoTArray<RefPtr<nsDOMMutationObserver>, 4>*
  33     nsDOMMutationObserver::sScheduledMutationObservers = nullptr;
  34
  35 uint32_t nsDOMMutationObserver::sMutationLevel = 0;
  36 uint64_t nsDOMMutationObserver::sCount = 0;
  37
  38 AutoTArray<AutoTArray<RefPtr<nsDOMMutationObserver>, 4>, 4>*
  39     nsDOMMutationObserver::sCurrentlyHandlingObservers = nullptr;
  40
  41 nsINodeList* nsDOMMutationRecord::AddedNodes() {
  42   if (!mAddedNodes) {
  43     mAddedNodes = new nsSimpleContentList(mTarget);
  44   }
  45   return mAddedNodes;
  46 }
  47
  48 nsINodeList* nsDOMMutationRecord::RemovedNodes() {
  49   if (!mRemovedNodes) {
  50     mRemovedNodes = new nsSimpleContentList(mTarget);
  51   }
  52   return mRemovedNodes;
  53 }
  54
  55 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMMutationRecord)
  56   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  57   NS_INTERFACE_MAP_ENTRY(nsISupports)
  58 NS_INTERFACE_MAP_END
  59
  60 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMMutationRecord)
  61 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMMutationRecord)
  62
  63 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(nsDOMMutationRecord, mTarget,
  64                                       mPreviousSibling, mNextSibling,
  65                                       mAddedNodes, mRemovedNodes,
  66                                       mAddedAnimations, mRemovedAnimations,
  67                                       mChangedAnimations, mNext, mOwner)
  68
  69 // Observer
  70
  71 bool nsMutationReceiverBase::IsObservable(nsIContent* aContent) {
  72   return !aContent->ChromeOnlyAccess() || ChromeOnlyNodes();
  73 }
  74
  75 bool nsMutationReceiverBase::ObservesAttr(nsINode* aRegisterTarget,
  76                                           Element* aElement,
  77                                           int32_t aNameSpaceID, nsAtom* aAttr) {
  78   if (mParent) {
  79     return mParent->ObservesAttr(aRegisterTarget, aElement, aNameSpaceID,
  80                                  aAttr);
  81   }
  82   if (!Attributes() || (!Subtree() && aElement != Target()) ||
  83       (Subtree() &&
  84        aRegisterTarget->SubtreeRoot() != aElement->SubtreeRoot()) ||
  85       !IsObservable(aElement)) {
  86     return false;
  87   }
  88   if (AllAttributes()) {
  89     return true;
  90   }
  91
  92   if (aNameSpaceID != kNameSpaceID_None) {
  93     return false;
  94   }
  95
  96   nsTArray<RefPtr<nsAtom>>& filters = AttributeFilter();
  97   for (size_t i = 0; i < filters.Length(); ++i) {
  98     if (filters[i] == aAttr) {
  99       return true;
 100     }
 101   }
 102   return false;
 103 }
 104
 105 NS_IMPL_ADDREF(nsMutationReceiver)
 106 NS_IMPL_RELEASE(nsMutationReceiver)
 107
 108 NS_INTERFACE_MAP_BEGIN(nsMutationReceiver)
 109   NS_INTERFACE_MAP_ENTRY(nsISupports)
 110   NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
 111 NS_INTERFACE_MAP_END
 112
 113 nsMutationReceiver::nsMutationReceiver(nsINode* aTarget,
 114                                        nsDOMMutationObserver* aObserver)
 115     : nsMutationReceiverBase(aTarget, aObserver) {
 116   mTarget->BindObject(aObserver);
 117 }
 118
 119 void nsMutationReceiver::Disconnect(bool aRemoveFromObserver) {
 120   if (mRegisterTarget) {
 121     mRegisterTarget->RemoveMutationObserver(this);
 122     mRegisterTarget = nullptr;
 123   }
 124
 125   mParent = nullptr;
 126   nsINode* target = mTarget;
 127   mTarget = nullptr;
 128   nsDOMMutationObserver* observer = mObserver;
 129   mObserver = nullptr;
 130   RemoveClones();
 131
 132   if (target && observer) {
 133     if (aRemoveFromObserver) {
 134       static_cast<nsDOMMutationObserver*>(observer)->RemoveReceiver(this);
 135     }
 136     // UnbindObject may delete 'this'!
 137     target->UnbindObject(observer);
 138   }
 139 }
 140
 141 void nsMutationReceiver::AttributeWillChange(Element* aElement,
 142                                              int32_t aNameSpaceID,
 143                                              nsAtom* aAttribute,
 144                                              int32_t aModType) {
 145   if (nsAutoMutationBatch::IsBatching() ||
 146       !ObservesAttr(RegisterTarget(), aElement, aNameSpaceID, aAttribute)) {
 147     return;
 148   }
 149
 150   nsDOMMutationRecord* m = Observer()->CurrentRecord(nsGkAtoms::attributes);
 151
 152   NS_ASSERTION(!m->mTarget || m->mTarget == aElement, "Wrong target!");
 153   NS_ASSERTION(!m->mAttrName || m->mAttrName == aAttribute, "Wrong attribute!");
 154   if (!m->mTarget) {
 155     m->mTarget = aElement;
 156     m->mAttrName = aAttribute;
 157     if (aNameSpaceID == kNameSpaceID_None) {
 158       m->mAttrNamespace.SetIsVoid(true);
 159     } else {
 160       nsNameSpaceManager::GetInstance()->GetNameSpaceURI(aNameSpaceID,
 161                                                          m->mAttrNamespace);
 162     }
 163   }
 164
 165   if (AttributeOldValue() && m->mPrevValue.IsVoid()) {
 166     if (!aElement->GetAttr(aNameSpaceID, aAttribute, m->mPrevValue)) {
 167       m->mPrevValue.SetIsVoid(true);
 168     }
 169   }
 170 }
 171
 172 void nsMutationReceiver::CharacterDataWillChange(
 173     nsIContent* aContent, const CharacterDataChangeInfo&) {
 174   if (nsAutoMutationBatch::IsBatching() || !CharacterData() ||
 175       (!Subtree() && aContent != Target()) ||
 176       (Subtree() &&
 177        RegisterTarget()->SubtreeRoot() != aContent->SubtreeRoot()) ||
 178       !IsObservable(aContent)) {
 179     return;
 180   }
 181
 182   nsDOMMutationRecord* m = Observer()->CurrentRecord(nsGkAtoms::characterData);
 183
 184   NS_ASSERTION(!m->mTarget || m->mTarget == aContent, "Wrong target!");
 185
 186   if (!m->mTarget) {
 187     m->mTarget = aContent;
 188   }
 189   if (CharacterDataOldValue() && m->mPrevValue.IsVoid()) {
 190     aContent->GetText()->AppendTo(m->mPrevValue);
 191   }
 192 }
 193
 194 void nsMutationReceiver::ContentAppended(nsIContent* aFirstNewContent) {
 195   nsINode* parent = aFirstNewContent->GetParentNode();
 196   bool wantsChildList =
 197       ChildList() && ((Subtree() && RegisterTarget()->SubtreeRoot() ==
 198                                         parent->SubtreeRoot()) ||
 199                       parent == Target());
 200   if (!wantsChildList || !IsObservable(aFirstNewContent)) {
 201     return;
 202   }
 203
 204   if (nsAutoMutationBatch::IsBatching()) {
 205     if (parent == nsAutoMutationBatch::GetBatchTarget()) {
 206       nsAutoMutationBatch::UpdateObserver(Observer(), wantsChildList);
 207     }
 208     return;
 209   }
 210
 211   nsDOMMutationRecord* m = Observer()->CurrentRecord(nsGkAtoms::childList);
 212   NS_ASSERTION(!m->mTarget || m->mTarget == parent, "Wrong target!");
 213   if (m->mTarget) {
 214     // Already handled case.
 215     return;
 216   }
 217   m->mTarget = parent;
 218   m->mAddedNodes = new nsSimpleContentList(parent);
 219
 220   nsINode* n = aFirstNewContent;
 221   while (n) {
 222     m->mAddedNodes->AppendElement(static_cast<nsIContent*>(n));
 223     n = n->GetNextSibling();
 224   }
 225   m->mPreviousSibling = aFirstNewContent->GetPreviousSibling();
 226 }
 227
 228 void nsMutationReceiver::ContentInserted(nsIContent* aChild) {
 229   nsINode* parent = aChild->GetParentNode();
 230   bool wantsChildList =
 231       ChildList() && ((Subtree() && RegisterTarget()->SubtreeRoot() ==
 232                                         parent->SubtreeRoot()) ||
 233                       parent == Target());
 234   if (!wantsChildList || !IsObservable(aChild)) {
 235     return;
 236   }
 237
 238   if (nsAutoMutationBatch::IsBatching()) {
 239     if (parent == nsAutoMutationBatch::GetBatchTarget()) {
 240       nsAutoMutationBatch::UpdateObserver(Observer(), wantsChildList);
 241     }
 242     return;
 243   }
 244
 245   nsDOMMutationRecord* m = Observer()->CurrentRecord(nsGkAtoms::childList);
 246   if (m->mTarget) {
 247     // Already handled case.
 248     return;
 249   }
 250   m->mTarget = parent;
 251   m->mAddedNodes = new nsSimpleContentList(parent);
 252   m->mAddedNodes->AppendElement(aChild);
 253   m->mPreviousSibling = aChild->GetPreviousSibling();
 254   m->mNextSibling = aChild->GetNextSibling();
 255 }
 256
 257 void nsMutationReceiver::ContentWillBeRemoved(nsIContent* aChild,
 258                                               const BatchRemovalState*) {
 259   if (!IsObservable(aChild)) {
 260     return;
 261   }
 262
 263   nsINode* parent = aChild->GetParentNode();
 264   if (Subtree() && parent->SubtreeRoot() != RegisterTarget()->SubtreeRoot()) {
 265     return;
 266   }
 267   if (nsAutoMutationBatch::IsBatching()) {
 268     if (nsAutoMutationBatch::IsRemovalDone()) {
 269       // This can happen for example if HTML parser parses to
 270       // context node, but needs to move elements around.
 271       return;
 272     }
 273     if (nsAutoMutationBatch::GetBatchTarget() != parent) {
 274       return;
 275     }
 276
 277     bool wantsChildList = ChildList() && (Subtree() || parent == Target());
 278     if (wantsChildList || Subtree()) {
 279       nsAutoMutationBatch::NodeRemoved(aChild);
 280       nsAutoMutationBatch::UpdateObserver(Observer(), wantsChildList);
 281     }
 282
 283     return;
 284   }
 285
 286   if (Subtree()) {
 287     // Try to avoid creating transient observer if the node
 288     // already has an observer observing the same set of nodes.
 289     nsMutationReceiver* orig = GetParent() ? GetParent() : this;
 290     if (Observer()->GetReceiverFor(aChild, false, false) != orig) {
 291       bool transientExists = false;
 292       bool isNewEntry = false;
 293       auto* const transientReceivers =
 294           Observer()
 295               ->mTransientReceivers
 296               .LookupOrInsertWith(
 297                   aChild,
 298                   [&isNewEntry] {
 299                     isNewEntry = true;
 300                     return MakeUnique<nsCOMArray<nsMutationReceiver>>();
 301                   })
 302               .get();
 303       if (!isNewEntry) {
 304         for (int32_t i = 0; i < transientReceivers->Count(); ++i) {
 305           nsMutationReceiver* r = transientReceivers->ObjectAt(i);
 306           if (r->GetParent() == orig) {
 307             transientExists = true;
 308           }
 309         }
 310       }
 311       if (!transientExists) {
 312         // Make sure the elements which are removed from the
 313         // subtree are kept in the same observation set.
 314         nsMutationReceiver* tr;
 315         if (orig->Animations()) {
 316           tr = nsAnimationReceiver::Create(aChild, orig);
 317         } else {
 318           tr = nsMutationReceiver::Create(aChild, orig);
 319         }
 320         transientReceivers->AppendObject(tr);
 321       }
 322     }
 323   }
 324
 325   if (ChildList() && (Subtree() || parent == Target())) {
 326     nsDOMMutationRecord* m = Observer()->CurrentRecord(nsGkAtoms::childList);
 327     if (m->mTarget) {
 328       // Already handled case.
 329       return;
 330     }
 331     MOZ_ASSERT(parent);
 332
 333     m->mTarget = parent;
 334     m->mRemovedNodes = new nsSimpleContentList(parent);
 335     m->mRemovedNodes->AppendElement(aChild);
 336     m->mPreviousSibling = aChild->GetPreviousSibling();
 337     m->mNextSibling = aChild->GetNextSibling();
 338   }
 339   // We need to schedule always, so that after microtask mTransientReceivers
 340   // can be cleared correctly.
 341   Observer()->ScheduleForRun();
 342 }
 343
 344 void nsMutationReceiver::NodeWillBeDestroyed(nsINode* aNode) {
 345   NS_ASSERTION(!mParent, "Shouldn't have mParent here!");
 346   Disconnect(true);
 347 }
 348
 349 void nsAnimationReceiver::RecordAnimationMutation(
 350     Animation* aAnimation, AnimationMutation aMutationType) {
 351   AnimationEffect* effect = aAnimation->GetEffect();
 352   if (!effect) {
 353     return;
 354   }
 355
 356   KeyframeEffect* keyframeEffect = effect->AsKeyframeEffect();
 357   if (!keyframeEffect) {
 358     return;
 359   }
 360
 361   NonOwningAnimationTarget animationTarget =
 362       keyframeEffect->GetAnimationTarget();
 363   if (!animationTarget) {
 364     return;
 365   }
 366
 367   Element* elem = animationTarget.mElement;
 368   if (!Animations() || !(Subtree() || elem == Target()) ||
 369       elem->ChromeOnlyAccess()) {
 370     return;
 371   }
 372
 373   // Record animations targeting to a pseudo element only when subtree is true.
 374   if (!animationTarget.mPseudoRequest.IsNotPseudo() && !Subtree()) {
 375     return;
 376   }
 377
 378   if (nsAutoAnimationMutationBatch::IsBatching()) {
 379     switch (aMutationType) {
 380       case eAnimationMutation_Added:
 381         nsAutoAnimationMutationBatch::AnimationAdded(aAnimation, elem);
 382         break;
 383       case eAnimationMutation_Changed:
 384         nsAutoAnimationMutationBatch::AnimationChanged(aAnimation, elem);
 385         break;
 386       case eAnimationMutation_Removed:
 387         nsAutoAnimationMutationBatch::AnimationRemoved(aAnimation, elem);
 388         break;
 389     }
 390
 391     nsAutoAnimationMutationBatch::AddObserver(Observer());
 392     return;
 393   }
 394
 395   nsDOMMutationRecord* m = Observer()->CurrentRecord(nsGkAtoms::animations);
 396
 397   NS_ASSERTION(!m->mTarget, "Wrong target!");
 398
 399   m->mTarget = elem;
 400
 401   switch (aMutationType) {
 402     case eAnimationMutation_Added:
 403       m->mAddedAnimations.AppendElement(aAnimation);
 404       break;
 405     case eAnimationMutation_Changed:
 406       m->mChangedAnimations.AppendElement(aAnimation);
 407       break;
 408     case eAnimationMutation_Removed:
 409       m->mRemovedAnimations.AppendElement(aAnimation);
 410       break;
 411   }
 412 }
 413
 414 void nsAnimationReceiver::AnimationAdded(Animation* aAnimation) {
 415   RecordAnimationMutation(aAnimation, eAnimationMutation_Added);
 416 }
 417
 418 void nsAnimationReceiver::AnimationChanged(Animation* aAnimation) {
 419   RecordAnimationMutation(aAnimation, eAnimationMutation_Changed);
 420 }
 421
 422 void nsAnimationReceiver::AnimationRemoved(Animation* aAnimation) {
 423   RecordAnimationMutation(aAnimation, eAnimationMutation_Removed);
 424 }
 425
 426 NS_IMPL_ISUPPORTS_INHERITED(nsAnimationReceiver, nsMutationReceiver,
 427                             nsIAnimationObserver)
 428
 429 // Observer
 430
 431 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMMutationObserver)
 432   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
 433   NS_INTERFACE_MAP_ENTRY(nsISupports)
 434   NS_INTERFACE_MAP_ENTRY(nsDOMMutationObserver)
 435 NS_INTERFACE_MAP_END
 436
 437 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMMutationObserver)
 438 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMMutationObserver)
 439
 440 NS_IMPL_CYCLE_COLLECTION_CLASS(nsDOMMutationObserver)
 441
 442 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(nsDOMMutationObserver)
 443   NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
 444 NS_IMPL_CYCLE_COLLECTION_TRACE_END
 445
 446 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDOMMutationObserver)
 447   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
 448   NS_IMPL_CYCLE_COLLECTION_UNLINK(mOwner)
 449   for (int32_t i = 0; i < tmp->mReceivers.Count(); ++i) {
 450     tmp->mReceivers[i]->Disconnect(false);
 451   }
 452   tmp->mReceivers.Clear();
 453   tmp->ClearPendingRecords();
 454   NS_IMPL_CYCLE_COLLECTION_UNLINK(mCallback)
 455 // No need to handle mTransientReceivers
 456 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 457
 458 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDOMMutationObserver)
 459   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOwner)
 460   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mReceivers)
 461   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFirstPendingMutation)
 462   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCallback)
 463   // No need to handle mTransientReceivers
 464 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 465
 466 nsMutationReceiver* nsDOMMutationObserver::GetReceiverFor(
 467     nsINode* aNode, bool aMayCreate, bool aWantsAnimations) {
 468   MOZ_ASSERT(aMayCreate || !aWantsAnimations,
 469              "the value of aWantsAnimations doesn't matter when aMayCreate is "
 470              "false, so just pass in false for it");
 471
 472   if (!aMayCreate && !aNode->MayHaveDOMMutationObserver()) {
 473     return nullptr;
 474   }
 475
 476   for (int32_t i = 0; i < mReceivers.Count(); ++i) {
 477     if (mReceivers[i]->Target() == aNode) {
 478       return mReceivers[i];
 479     }
 480   }
 481   if (!aMayCreate) {
 482     return nullptr;
 483   }
 484
 485   nsMutationReceiver* r;
 486   if (aWantsAnimations) {
 487     r = nsAnimationReceiver::Create(aNode, this);
 488   } else {
 489     r = nsMutationReceiver::Create(aNode, this);
 490   }
 491   mReceivers.AppendObject(r);
 492   return r;
 493 }
 494
 495 void nsDOMMutationObserver::RemoveReceiver(nsMutationReceiver* aReceiver) {
 496   mReceivers.RemoveObject(aReceiver);
 497 }
 498
 499 void nsDOMMutationObserver::GetAllSubtreeObserversFor(
 500     nsINode* aNode, nsTArray<nsMutationReceiver*>& aReceivers) {
 501   nsINode* n = aNode;
 502   while (n) {
 503     if (n->MayHaveDOMMutationObserver()) {
 504       nsMutationReceiver* r = GetReceiverFor(n, false, false);
 505       if (r && r->Subtree() && !aReceivers.Contains(r)) {
 506         aReceivers.AppendElement(r);
 507         // If we've found all the receivers the observer has,
 508         // no need to search for more.
 509         if (mReceivers.Count() == int32_t(aReceivers.Length())) {
 510           return;
 511         }
 512       }
 513       nsCOMArray<nsMutationReceiver>* transientReceivers = nullptr;
 514       if (mTransientReceivers.Get(n, &transientReceivers) &&
 515           transientReceivers) {
 516         for (int32_t i = 0; i < transientReceivers->Count(); ++i) {
 517           nsMutationReceiver* r = transientReceivers->ObjectAt(i);
 518           nsMutationReceiver* parent = r->GetParent();
 519           if (r->Subtree() && parent && !aReceivers.Contains(parent)) {
 520             aReceivers.AppendElement(parent);
 521           }
 522         }
 523         if (mReceivers.Count() == int32_t(aReceivers.Length())) {
 524           return;
 525         }
 526       }
 527     }
 528     n = n->GetParentNode();
 529   }
 530 }
 531
 532 void nsDOMMutationObserver::ScheduleForRun() {
 533   nsDOMMutationObserver::AddCurrentlyHandlingObserver(this, sMutationLevel);
 534
 535   if (mWaitingForRun) {
 536     return;
 537   }
 538   mWaitingForRun = true;
 539   RescheduleForRun();
 540 }
 541
 542 class MutationObserverMicroTask final : public MicroTaskRunnable {
 543  public:
 544   MOZ_CAN_RUN_SCRIPT
 545   virtual void Run(AutoSlowOperation& aAso) override {
 546     nsDOMMutationObserver::HandleMutations(aAso);
 547   }
 548
 549   virtual bool Suppressed() override {
 550     return nsDOMMutationObserver::AllScheduledMutationObserversAreSuppressed();
 551   }
 552 };
 553
 554 /* static */
 555 void nsDOMMutationObserver::QueueMutationObserverMicroTask() {
 556   CycleCollectedJSContext* ccjs = CycleCollectedJSContext::Get();
 557   if (!ccjs) {
 558     return;
 559   }
 560
 561   RefPtr<MutationObserverMicroTask> momt = new MutationObserverMicroTask();
 562   ccjs->DispatchToMicroTask(momt.forget());
 563 }
 564
 565 void nsDOMMutationObserver::HandleMutations(mozilla::AutoSlowOperation& aAso) {
 566   if (sScheduledMutationObservers || DocGroup::sPendingDocGroups) {
 567     HandleMutationsInternal(aAso);
 568   }
 569 }
 570
 571 void nsDOMMutationObserver::RescheduleForRun() {
 572   if (!sScheduledMutationObservers) {
 573     CycleCollectedJSContext* ccjs = CycleCollectedJSContext::Get();
 574     if (!ccjs) {
 575       return;
 576     }
 577
 578     RefPtr<MutationObserverMicroTask> momt = new MutationObserverMicroTask();
 579     ccjs->DispatchToMicroTask(momt.forget());
 580     sScheduledMutationObservers =
 581         new AutoTArray<RefPtr<nsDOMMutationObserver>, 4>;
 582   }
 583
 584   bool didInsert = false;
 585   for (uint32_t i = 0; i < sScheduledMutationObservers->Length(); ++i) {
 586     if (static_cast<nsDOMMutationObserver*>((*sScheduledMutationObservers)[i])
 587             ->mId > mId) {
 588       sScheduledMutationObservers->InsertElementAt(i, this);
 589       didInsert = true;
 590       break;
 591     }
 592   }
 593   if (!didInsert) {
 594     sScheduledMutationObservers->AppendElement(this);
 595   }
 596 }
 597
 598 void nsDOMMutationObserver::Observe(nsINode& aTarget,
 599                                     const MutationObserverInit& aOptions,
 600                                     nsIPrincipal& aSubjectPrincipal,
 601                                     ErrorResult& aRv) {
 602   bool childList = aOptions.mChildList;
 603   bool attributes =
 604       aOptions.mAttributes.WasPassed() && aOptions.mAttributes.Value();
 605   bool characterData =
 606       aOptions.mCharacterData.WasPassed() && aOptions.mCharacterData.Value();
 607   bool subtree = aOptions.mSubtree;
 608   bool attributeOldValue = aOptions.mAttributeOldValue.WasPassed() &&
 609                            aOptions.mAttributeOldValue.Value();
 610   bool characterDataOldValue = aOptions.mCharacterDataOldValue.WasPassed() &&
 611                                aOptions.mCharacterDataOldValue.Value();
 612   bool animations = aOptions.mAnimations;
 613   bool chromeOnlyNodes = aOptions.mChromeOnlyNodes;
 614
 615   if (!aOptions.mAttributes.WasPassed() &&
 616       (aOptions.mAttributeOldValue.WasPassed() ||
 617        aOptions.mAttributeFilter.WasPassed())) {
 618     attributes = true;
 619   }
 620
 621   if (!aOptions.mCharacterData.WasPassed() &&
 622       aOptions.mCharacterDataOldValue.WasPassed()) {
 623     characterData = true;
 624   }
 625
 626   if (!(childList || attributes || characterData || animations)) {
 627     aRv.ThrowTypeError(
 628         "One of 'childList', 'attributes', 'characterData' must not be false.");
 629     return;
 630   }
 631
 632   if (aOptions.mAttributeOldValue.WasPassed() &&
 633       aOptions.mAttributeOldValue.Value() && !attributes) {
 634     aRv.ThrowTypeError(
 635         "If 'attributeOldValue' is true, 'attributes' must not be false.");
 636     return;
 637   }
 638
 639   if (aOptions.mAttributeFilter.WasPassed() && !attributes) {
 640     aRv.ThrowTypeError(
 641         "If 'attributesFilter' is present, 'attributes' must not be false.");
 642     return;
 643   }
 644
 645   if (aOptions.mCharacterDataOldValue.WasPassed() &&
 646       aOptions.mCharacterDataOldValue.Value() && !characterData) {
 647     aRv.ThrowTypeError(
 648         "If 'characterDataOldValue' is true, 'characterData' must not be "
 649         "false.");
 650     return;
 651   }
 652
 653   nsTArray<RefPtr<nsAtom>> filters;
 654   bool allAttrs = true;
 655   if (aOptions.mAttributeFilter.WasPassed()) {
 656     allAttrs = false;
 657     const Sequence<nsString>& filtersAsString =
 658         aOptions.mAttributeFilter.Value();
 659     uint32_t len = filtersAsString.Length();
 660     filters.SetCapacity(len);
 661
 662     for (uint32_t i = 0; i < len; ++i) {
 663       filters.AppendElement(NS_Atomize(filtersAsString[i]));
 664     }
 665   }
 666
 667   nsMutationReceiver* r = GetReceiverFor(&aTarget, true, animations);
 668   r->SetChildList(childList);
 669   r->SetAttributes(attributes);
 670   r->SetCharacterData(characterData);
 671   r->SetSubtree(subtree);
 672   r->SetAttributeOldValue(attributeOldValue);
 673   r->SetCharacterDataOldValue(characterDataOldValue);
 674   r->SetAttributeFilter(std::move(filters));
 675   r->SetAllAttributes(allAttrs);
 676   r->SetAnimations(animations);
 677   r->SetChromeOnlyNodes(chromeOnlyNodes);
 678   r->RemoveClones();
 679
 680   if (!aSubjectPrincipal.IsSystemPrincipal() &&
 681       !aSubjectPrincipal.GetIsAddonOrExpandedAddonPrincipal()) {
 682     if (nsPIDOMWindowInner* window = aTarget.OwnerDoc()->GetInnerWindow()) {
 683       window->SetMutationObserverHasObservedNodeForTelemetry();
 684     }
 685   }
 686
 687 #ifdef DEBUG
 688   for (int32_t i = 0; i < mReceivers.Count(); ++i) {
 689     NS_WARNING_ASSERTION(mReceivers[i]->Target(),
 690                          "All the receivers should have a target!");
 691   }
 692 #endif
 693 }
 694
 695 void nsDOMMutationObserver::Disconnect() {
 696   for (int32_t i = 0; i < mReceivers.Count(); ++i) {
 697     mReceivers[i]->Disconnect(false);
 698   }
 699   mReceivers.Clear();
 700   mCurrentMutations.Clear();
 701   ClearPendingRecords();
 702 }
 703
 704 void nsDOMMutationObserver::TakeRecords(
 705     nsTArray<RefPtr<nsDOMMutationRecord>>& aRetVal) {
 706   aRetVal.Clear();
 707   aRetVal.SetCapacity(mPendingMutationCount);
 708   RefPtr<nsDOMMutationRecord> current;
 709   current.swap(mFirstPendingMutation);
 710   for (uint32_t i = 0; i < mPendingMutationCount; ++i) {
 711     RefPtr<nsDOMMutationRecord> next;
 712     current->mNext.swap(next);
 713     if (!mMergeAttributeRecords ||
 714         !MergeableAttributeRecord(aRetVal.SafeLastElement(nullptr), current)) {
 715       *aRetVal.AppendElement() = std::move(current);
 716     }
 717     current.swap(next);
 718   }
 719   ClearPendingRecords();
 720 }
 721
 722 void nsDOMMutationObserver::GetObservingInfo(
 723     nsTArray<Nullable<MutationObservingInfo>>& aResult,
 724     mozilla::ErrorResult& aRv) {
 725   aResult.SetCapacity(mReceivers.Count());
 726   for (int32_t i = 0; i < mReceivers.Count(); ++i) {
 727     MutationObservingInfo& info = aResult.AppendElement()->SetValue();
 728     nsMutationReceiver* mr = mReceivers[i];
 729     info.mChildList = mr->ChildList();
 730     info.mAttributes.Construct(mr->Attributes());
 731     info.mCharacterData.Construct(mr->CharacterData());
 732     info.mSubtree = mr->Subtree();
 733     info.mAttributeOldValue.Construct(mr->AttributeOldValue());
 734     info.mCharacterDataOldValue.Construct(mr->CharacterDataOldValue());
 735     info.mAnimations = mr->Animations();
 736     nsTArray<RefPtr<nsAtom>>& filters = mr->AttributeFilter();
 737     if (filters.Length()) {
 738       info.mAttributeFilter.Construct();
 739       Sequence<nsString>& filtersAsStrings = info.mAttributeFilter.Value();
 740       nsString* strings =
 741           filtersAsStrings.AppendElements(filters.Length(), mozilla::fallible);
 742       if (!strings) {
 743         aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
 744         return;
 745       }
 746       for (size_t j = 0; j < filters.Length(); ++j) {
 747         filters[j]->ToString(strings[j]);
 748       }
 749     }
 750     info.mObservedNode = mr->Target();
 751   }
 752 }
 753
 754 // static
 755 already_AddRefed<nsDOMMutationObserver> nsDOMMutationObserver::Constructor(
 756     const GlobalObject& aGlobal, dom::MutationCallback& aCb, ErrorResult& aRv) {
 757   nsCOMPtr<nsPIDOMWindowInner> window =
 758       do_QueryInterface(aGlobal.GetAsSupports());
 759   if (!window) {
 760     aRv.Throw(NS_ERROR_FAILURE);
 761     return nullptr;
 762   }
 763   return MakeAndAddRef<nsDOMMutationObserver>(std::move(window), aCb);
 764 }
 765
 766 bool nsDOMMutationObserver::MergeableAttributeRecord(
 767     nsDOMMutationRecord* aOldRecord, nsDOMMutationRecord* aRecord) {
 768   MOZ_ASSERT(mMergeAttributeRecords);
 769   return aOldRecord && aOldRecord->mType == nsGkAtoms::attributes &&
 770          aOldRecord->mType == aRecord->mType &&
 771          aOldRecord->mTarget == aRecord->mTarget &&
 772          aOldRecord->mAttrName == aRecord->mAttrName &&
 773          aOldRecord->mAttrNamespace.Equals(aRecord->mAttrNamespace);
 774 }
 775
 776 void nsDOMMutationObserver::HandleMutation() {
 777   NS_ASSERTION(nsContentUtils::IsSafeToRunScript(), "Whaat!");
 778   NS_ASSERTION(mCurrentMutations.IsEmpty(),
 779                "Still generating MutationRecords?");
 780
 781   mWaitingForRun = false;
 782
 783   for (int32_t i = 0; i < mReceivers.Count(); ++i) {
 784     mReceivers[i]->RemoveClones();
 785   }
 786   mTransientReceivers.Clear();
 787
 788   nsPIDOMWindowOuter* outer = mOwner->GetOuterWindow();
 789   if (!mPendingMutationCount || !outer ||
 790       outer->GetCurrentInnerWindow() != mOwner) {
 791     ClearPendingRecords();
 792     return;
 793   }
 794
 795   mozilla::dom::Sequence<mozilla::OwningNonNull<nsDOMMutationRecord>> mutations;
 796   if (mutations.SetCapacity(mPendingMutationCount, mozilla::fallible)) {
 797     // We can't use TakeRecords easily here, because it deals with a
 798     // different type of array, and we want to optimize out any extra copying.
 799     RefPtr<nsDOMMutationRecord> current;
 800     current.swap(mFirstPendingMutation);
 801     for (uint32_t i = 0; i < mPendingMutationCount; ++i) {
 802       RefPtr<nsDOMMutationRecord> next;
 803       current->mNext.swap(next);
 804       if (!mMergeAttributeRecords ||
 805           !MergeableAttributeRecord(
 806               mutations.Length() ? mutations.LastElement().get() : nullptr,
 807               current)) {
 808         *mutations.AppendElement(mozilla::fallible) = current;
 809       }
 810       current.swap(next);
 811     }
 812   }
 813   ClearPendingRecords();
 814
 815   RefPtr<dom::MutationCallback> callback(mCallback);
 816   callback->Call(this, mutations, *this);
 817 }
 818
 819 void nsDOMMutationObserver::HandleMutationsInternal(AutoSlowOperation& aAso) {
 820   nsTArray<RefPtr<nsDOMMutationObserver>>* suppressedObservers = nullptr;
 821
 822   // This loop implements:
 823   //  * Let signalList be a copy of unit of related similar-origin browsing
 824   //    contexts' signal slot list.
 825   //  * Empty unit of related similar-origin browsing contexts' signal slot
 826   //    list.
 827   nsTArray<nsTArray<RefPtr<HTMLSlotElement>>> signalLists;
 828   if (DocGroup::sPendingDocGroups) {
 829     signalLists.SetCapacity(DocGroup::sPendingDocGroups->Length());
 830     for (DocGroup* docGroup : *DocGroup::sPendingDocGroups) {
 831       signalLists.AppendElement(docGroup->MoveSignalSlotList());
 832     }
 833     delete DocGroup::sPendingDocGroups;
 834     DocGroup::sPendingDocGroups = nullptr;
 835   }
 836
 837   if (sScheduledMutationObservers) {
 838     AutoTArray<RefPtr<nsDOMMutationObserver>, 4>* observers =
 839         sScheduledMutationObservers;
 840     sScheduledMutationObservers = nullptr;
 841     for (uint32_t i = 0; i < observers->Length(); ++i) {
 842       RefPtr<nsDOMMutationObserver> currentObserver =
 843           static_cast<nsDOMMutationObserver*>((*observers)[i]);
 844       if (!currentObserver->Suppressed()) {
 845         currentObserver->HandleMutation();
 846       } else {
 847         if (!suppressedObservers) {
 848           suppressedObservers = new nsTArray<RefPtr<nsDOMMutationObserver>>;
 849         }
 850         if (!suppressedObservers->Contains(currentObserver)) {
 851           suppressedObservers->AppendElement(currentObserver);
 852         }
 853       }
 854     }
 855     delete observers;
 856     aAso.CheckForInterrupt();
 857   }
 858
 859   if (suppressedObservers) {
 860     for (uint32_t i = 0; i < suppressedObservers->Length(); ++i) {
 861       static_cast<nsDOMMutationObserver*>(suppressedObservers->ElementAt(i))
 862           ->RescheduleForRun();
 863     }
 864     delete suppressedObservers;
 865     suppressedObservers = nullptr;
 866   }
 867
 868   // Fire slotchange event for each slot in signalLists.
 869   for (const nsTArray<RefPtr<HTMLSlotElement>>& signalList : signalLists) {
 870     for (const RefPtr<HTMLSlotElement>& signal : signalList) {
 871       signal->FireSlotChangeEvent();
 872     }
 873   }
 874 }
 875
 876 nsDOMMutationRecord* nsDOMMutationObserver::CurrentRecord(nsAtom* aType) {
 877   NS_ASSERTION(sMutationLevel > 0, "Unexpected mutation level!");
 878
 879   while (mCurrentMutations.Length() < sMutationLevel) {
 880     mCurrentMutations.AppendElement(static_cast<nsDOMMutationRecord*>(nullptr));
 881   }
 882
 883   uint32_t last = sMutationLevel - 1;
 884   if (!mCurrentMutations[last]) {
 885     RefPtr<nsDOMMutationRecord> r =
 886         new nsDOMMutationRecord(aType, GetParentObject());
 887     mCurrentMutations[last] = r;
 888     AppendMutationRecord(r.forget());
 889     ScheduleForRun();
 890   }
 891
 892 #ifdef DEBUG
 893   MOZ_ASSERT(sCurrentlyHandlingObservers->Length() == sMutationLevel);
 894   for (size_t i = 0; i < sCurrentlyHandlingObservers->Length(); ++i) {
 895     MOZ_ASSERT(sCurrentlyHandlingObservers->ElementAt(i).Contains(this),
 896                "MutationObserver should be added as an observer of all the "
 897                "nested mutations!");
 898   }
 899 #endif
 900
 901   NS_ASSERTION(mCurrentMutations[last]->mType == aType,
 902                "Unexpected MutationRecord type!");
 903
 904   return mCurrentMutations[last];
 905 }
 906
 907 nsDOMMutationObserver::~nsDOMMutationObserver() {
 908   for (int32_t i = 0; i < mReceivers.Count(); ++i) {
 909     mReceivers[i]->RemoveClones();
 910   }
 911 }
 912
 913 void nsDOMMutationObserver::EnterMutationHandling() { ++sMutationLevel; }
 914
 915 // Leave the current mutation level (there can be several levels if in case
 916 // of nested calls to the nsIMutationObserver methods).
 917 // The most recent mutation record is removed from mCurrentMutations, so
 918 // that is doesn't get modified anymore by receivers.
 919 void nsDOMMutationObserver::LeaveMutationHandling() {
 920   if (sCurrentlyHandlingObservers &&
 921       sCurrentlyHandlingObservers->Length() == sMutationLevel) {
 922     nsTArray<RefPtr<nsDOMMutationObserver>> obs =
 923         sCurrentlyHandlingObservers->PopLastElement();
 924     for (uint32_t i = 0; i < obs.Length(); ++i) {
 925       nsDOMMutationObserver* o = static_cast<nsDOMMutationObserver*>(obs[i]);
 926       if (o->mCurrentMutations.Length() == sMutationLevel) {
 927         // It is already in pending mutations.
 928         o->mCurrentMutations.RemoveLastElement();
 929       }
 930     }
 931   }
 932   --sMutationLevel;
 933 }
 934
 935 void nsDOMMutationObserver::AddCurrentlyHandlingObserver(
 936     nsDOMMutationObserver* aObserver, uint32_t aMutationLevel) {
 937   NS_ASSERTION(aMutationLevel > 0, "Unexpected mutation level!");
 938
 939   if (aMutationLevel > 1) {
 940     // MutationObserver must be in the currently handling observer list
 941     // in all the nested levels.
 942     AddCurrentlyHandlingObserver(aObserver, aMutationLevel - 1);
 943   }
 944
 945   if (!sCurrentlyHandlingObservers) {
 946     sCurrentlyHandlingObservers =
 947         new AutoTArray<AutoTArray<RefPtr<nsDOMMutationObserver>, 4>, 4>;
 948   }
 949
 950   while (sCurrentlyHandlingObservers->Length() < aMutationLevel) {
 951     sCurrentlyHandlingObservers->InsertElementAt(
 952         sCurrentlyHandlingObservers->Length());
 953   }
 954
 955   uint32_t index = aMutationLevel - 1;
 956   if (!sCurrentlyHandlingObservers->ElementAt(index).Contains(aObserver)) {
 957     sCurrentlyHandlingObservers->ElementAt(index).AppendElement(aObserver);
 958   }
 959 }
 960
 961 void nsDOMMutationObserver::Shutdown() {
 962   delete sCurrentlyHandlingObservers;
 963   sCurrentlyHandlingObservers = nullptr;
 964   delete sScheduledMutationObservers;
 965   sScheduledMutationObservers = nullptr;
 966 }
 967
 968 nsAutoMutationBatch* nsAutoMutationBatch::sCurrentBatch = nullptr;
 969
 970 void nsAutoMutationBatch::Done() {
 971   if (sCurrentBatch != this) {
 972     return;
 973   }
 974
 975   sCurrentBatch = mPreviousBatch;
 976   if (mObservers.IsEmpty()) {
 977     nsDOMMutationObserver::LeaveMutationHandling();
 978     // Nothing to do.
 979     return;
 980   }
 981
 982   uint32_t len = mObservers.Length();
 983   for (uint32_t i = 0; i < len; ++i) {
 984     nsDOMMutationObserver* ob = mObservers[i].mObserver;
 985     bool wantsChildList = mObservers[i].mWantsChildList;
 986
 987     RefPtr<nsSimpleContentList> removedList;
 988     if (wantsChildList) {
 989       removedList = new nsSimpleContentList(mBatchTarget);
 990     }
 991
 992     nsTArray<nsMutationReceiver*> allObservers;
 993     ob->GetAllSubtreeObserversFor(mBatchTarget, allObservers);
 994
 995     int32_t j = mFromFirstToLast ? 0 : mRemovedNodes.Length() - 1;
 996     int32_t end = mFromFirstToLast ? mRemovedNodes.Length() : -1;
 997     for (; j != end; mFromFirstToLast ? ++j : --j) {
 998       nsCOMPtr<nsIContent> removed = mRemovedNodes[j];
 999       if (removedList) {
1000         removedList->AppendElement(removed);
1001       }
1002
1003       if (allObservers.Length()) {
1004         auto* const transientReceivers =
1005             ob->mTransientReceivers.GetOrInsertNew(removed);
1006         for (uint32_t k = 0; k < allObservers.Length(); ++k) {
1007           nsMutationReceiver* r = allObservers[k];
1008           nsMutationReceiver* orig = r->GetParent() ? r->GetParent() : r;
1009           if (ob->GetReceiverFor(removed, false, false) != orig) {
1010             // Make sure the elements which are removed from the
1011             // subtree are kept in the same observation set.
1012             nsMutationReceiver* tr;
1013             if (orig->Animations()) {
1014               tr = nsAnimationReceiver::Create(removed, orig);
1015             } else {
1016               tr = nsMutationReceiver::Create(removed, orig);
1017             }
1018             transientReceivers->AppendObject(tr);
1019           }
1020         }
1021       }
1022     }
1023     if (wantsChildList && (mRemovedNodes.Length() || mAddedNodes.Length())) {
1024       RefPtr<nsSimpleContentList> addedList =
1025           new nsSimpleContentList(mBatchTarget);
1026       for (uint32_t i = 0; i < mAddedNodes.Length(); ++i) {
1027         addedList->AppendElement(mAddedNodes[i]);
1028       }
1029       RefPtr<nsDOMMutationRecord> m =
1030           new nsDOMMutationRecord(nsGkAtoms::childList, ob->GetParentObject());
1031       m->mTarget = mBatchTarget;
1032       m->mRemovedNodes = removedList;
1033       m->mAddedNodes = addedList;
1034       m->mPreviousSibling = mPrevSibling;
1035       m->mNextSibling = mNextSibling;
1036       ob->AppendMutationRecord(m.forget());
1037     }
1038     // Always schedule the observer so that transient receivers are
1039     // removed correctly.
1040     ob->ScheduleForRun();
1041   }
1042   nsDOMMutationObserver::LeaveMutationHandling();
1043 }
1044
1045 nsAutoAnimationMutationBatch* nsAutoAnimationMutationBatch::sCurrentBatch =
1046     nullptr;
1047
1048 void nsAutoAnimationMutationBatch::Done() {
1049   if (sCurrentBatch != this) {
1050     return;
1051   }
1052
1053   sCurrentBatch = nullptr;
1054   if (mObservers.IsEmpty()) {
1055     nsDOMMutationObserver::LeaveMutationHandling();
1056     // Nothing to do.
1057     return;
1058   }
1059
1060   mBatchTargets.Sort(TreeOrderComparator());
1061
1062   for (nsDOMMutationObserver* ob : mObservers) {
1063     bool didAddRecords = false;
1064
1065     for (nsINode* target : mBatchTargets) {
1066       EntryArray* entries = mEntryTable.Get(target);
1067       MOZ_ASSERT(entries,
1068                  "Targets in entry table and targets list should match");
1069
1070       RefPtr<nsDOMMutationRecord> m =
1071           new nsDOMMutationRecord(nsGkAtoms::animations, ob->GetParentObject());
1072       m->mTarget = target;
1073
1074       for (const Entry& e : *entries) {
1075         if (e.mState == eState_Added) {
1076           m->mAddedAnimations.AppendElement(e.mAnimation);
1077         } else if (e.mState == eState_Removed) {
1078           m->mRemovedAnimations.AppendElement(e.mAnimation);
1079         } else if (e.mState == eState_RemainedPresent && e.mChanged) {
1080           m->mChangedAnimations.AppendElement(e.mAnimation);
1081         }
1082       }
1083
1084       if (!m->mAddedAnimations.IsEmpty() || !m->mChangedAnimations.IsEmpty() ||
1085           !m->mRemovedAnimations.IsEmpty()) {
1086         ob->AppendMutationRecord(m.forget());
1087         didAddRecords = true;
1088       }
1089     }
1090
1091     if (didAddRecords) {
1092       ob->ScheduleForRun();
1093     }
1094   }
1095   nsDOMMutationObserver::LeaveMutationHandling();
1096 }