DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (4a108e94d3e2)

VCS Links

Line Code
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
/* -*- Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 8; -*- */
/* vim: set sw=4 ts=8 et 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/. */

#ifndef nsDOMMutationObserver_h
#define nsDOMMutationObserver_h

#include "mozilla/Attributes.h"
#include "nsCycleCollectionParticipant.h"
#include "nsPIDOMWindow.h"
#include "nsIScriptContext.h"
#include "nsStubMutationObserver.h"
#include "nsCOMArray.h"
#include "nsTArray.h"
#include "nsAutoPtr.h"
#include "nsIVariant.h"
#include "nsContentList.h"
#include "mozilla/dom/Element.h"
#include "nsClassHashtable.h"
#include "nsNodeUtils.h"
#include "nsIDOMMutationEvent.h"
#include "nsWrapperCache.h"
#include "mozilla/dom/MutationObserverBinding.h"
#include "nsIDocument.h"

class nsDOMMutationObserver;
using mozilla::dom::MutationObservingInfo;

class nsDOMMutationRecord final : public nsISupports,
                                      public nsWrapperCache
{
  virtual ~nsDOMMutationRecord() {}

public:
  nsDOMMutationRecord(nsIAtom* aType, nsISupports* aOwner)
  : mType(aType), mAttrNamespace(NullString()), mPrevValue(NullString()), mOwner(aOwner)
  {
  }

  nsISupports* GetParentObject() const
  {
    return mOwner;
  }

  virtual JSObject* WrapObject(JSContext* aCx) override
  {
    return mozilla::dom::MutationRecordBinding::Wrap(aCx, this);
  }

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsDOMMutationRecord)

  void GetType(mozilla::dom::DOMString& aRetVal) const
  {
    aRetVal.SetOwnedAtom(mType, mozilla::dom::DOMString::eNullNotExpected);
  }

  nsINode* GetTarget() const
  {
    return mTarget;
  }

  nsINodeList* AddedNodes();

  nsINodeList* RemovedNodes();

  nsINode* GetPreviousSibling() const
  {
    return mPreviousSibling;
  }

  nsINode* GetNextSibling() const
  {
    return mNextSibling;
  }

  void GetAttributeName(mozilla::dom::DOMString& aRetVal) const
  {
    aRetVal.SetOwnedAtom(mAttrName, mozilla::dom::DOMString::eTreatNullAsNull);
  }

  void GetAttributeNamespace(mozilla::dom::DOMString& aRetVal) const
  {
    aRetVal.SetOwnedString(mAttrNamespace);
  }

  void GetOldValue(mozilla::dom::DOMString& aRetVal) const
  {
    aRetVal.SetOwnedString(mPrevValue);
  }

  nsCOMPtr<nsINode>             mTarget;
  nsCOMPtr<nsIAtom>             mType;
  nsCOMPtr<nsIAtom>             mAttrName;
  nsString                      mAttrNamespace;
  nsString                      mPrevValue;
  nsRefPtr<nsSimpleContentList> mAddedNodes;
  nsRefPtr<nsSimpleContentList> mRemovedNodes;
  nsCOMPtr<nsINode>             mPreviousSibling;
  nsCOMPtr<nsINode>             mNextSibling;

  nsRefPtr<nsDOMMutationRecord> mNext;
  nsCOMPtr<nsISupports>         mOwner;
};
 
// Base class just prevents direct access to
// members to make sure we go through getters/setters.
class nsMutationReceiverBase : public nsStubMutationObserver
{
public:
  virtual ~nsMutationReceiverBase() { }

  nsDOMMutationObserver* Observer();
  nsINode* Target() { return mParent ? mParent->Target() : mTarget; }
  nsINode* RegisterTarget() { return mRegisterTarget; }

  bool Subtree() { return mParent ? mParent->Subtree() : mSubtree; }
  void SetSubtree(bool aSubtree)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mSubtree = aSubtree;
  }

  bool ChildList() { return mParent ? mParent->ChildList() : mChildList; }
  void SetChildList(bool aChildList)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mChildList = aChildList;
  }

  bool CharacterData()
  {
    return mParent ? mParent->CharacterData() : mCharacterData;
  }
  void SetCharacterData(bool aCharacterData)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mCharacterData = aCharacterData;
  }

  bool CharacterDataOldValue()
  {
    return mParent ? mParent->CharacterDataOldValue() : mCharacterDataOldValue;
  }
  void SetCharacterDataOldValue(bool aOldValue)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mCharacterDataOldValue = aOldValue;
  }

  bool Attributes() { return mParent ? mParent->Attributes() : mAttributes; }
  void SetAttributes(bool aAttributes)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mAttributes = aAttributes;
  }

  bool AllAttributes()
  {
    return mParent ? mParent->AllAttributes()
                   : mAllAttributes;
  }
  void SetAllAttributes(bool aAll)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mAllAttributes = aAll;
  }

  bool AttributeOldValue() {
    return mParent ? mParent->AttributeOldValue()
                   : mAttributeOldValue;
  }
  void SetAttributeOldValue(bool aOldValue)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mAttributeOldValue = aOldValue;
  }

  nsCOMArray<nsIAtom>& AttributeFilter() { return mAttributeFilter; }
  void SetAttributeFilter(nsCOMArray<nsIAtom>& aFilter)
  {
    NS_ASSERTION(!mParent, "Shouldn't have parent");
    mAttributeFilter.Clear();
    mAttributeFilter.AppendObjects(aFilter);
  }

  void AddClone(nsMutationReceiverBase* aClone)
  {
    mTransientReceivers.AppendObject(aClone);
  }

  void RemoveClone(nsMutationReceiverBase* aClone)
  {
    mTransientReceivers.RemoveObject(aClone);
  }
  
protected:
  nsMutationReceiverBase(nsINode* aTarget, nsDOMMutationObserver* aObserver)
  : mTarget(aTarget), mObserver(aObserver), mRegisterTarget(aTarget)
  {
    mRegisterTarget->AddMutationObserver(this);
    mRegisterTarget->SetMayHaveDOMMutationObserver();
    mRegisterTarget->OwnerDoc()->SetMayHaveDOMMutationObservers();
  }

  nsMutationReceiverBase(nsINode* aRegisterTarget,
                         nsMutationReceiverBase* aParent)
  : mTarget(nullptr), mObserver(nullptr), mParent(aParent),
    mRegisterTarget(aRegisterTarget), mKungFuDeathGrip(aParent->Target())
  {
    NS_ASSERTION(mParent->Subtree(), "Should clone a non-subtree observer!");
    mRegisterTarget->AddMutationObserver(this);
    mRegisterTarget->SetMayHaveDOMMutationObserver();
    mRegisterTarget->OwnerDoc()->SetMayHaveDOMMutationObservers();
  }

  bool ObservesAttr(mozilla::dom::Element* aElement,
                    int32_t aNameSpaceID,
                    nsIAtom* aAttr)
  {
    if (mParent) {
      return mParent->ObservesAttr(aElement, aNameSpaceID, aAttr);
    }
    if (!Attributes() || (!Subtree() && aElement != Target())) {
      return false;
    }
    if (AllAttributes()) {
      return true;
    }

    if (aNameSpaceID != kNameSpaceID_None) {
      return false;
    }

    nsCOMArray<nsIAtom>& filters = AttributeFilter();
    for (int32_t i = 0; i < filters.Count(); ++i) {
      if (filters[i] == aAttr) {
        return true;
      }
    }
    return false;
  }

  // The target for the MutationObserver.observe() method.
  nsINode*                           mTarget;
  nsDOMMutationObserver*             mObserver;
  nsRefPtr<nsMutationReceiverBase>   mParent; // Cleared after microtask.
  // The node to which Gecko-internal nsIMutationObserver was registered to.
  // This is different than mTarget when dealing with transient observers.
  nsINode*                           mRegisterTarget;
  nsCOMArray<nsMutationReceiverBase> mTransientReceivers;
  // While we have transient receivers, keep the original mutation receiver
  // alive so it doesn't go away and disconnect all its transient receivers.
  nsCOMPtr<nsINode>                  mKungFuDeathGrip;
  
private:
  bool                               mSubtree;
  bool                               mChildList;
  bool                               mCharacterData;
  bool                               mCharacterDataOldValue;
  bool                               mAttributes;
  bool                               mAllAttributes;
  bool                               mAttributeOldValue;
  nsCOMArray<nsIAtom>                mAttributeFilter;
};


class nsMutationReceiver : public nsMutationReceiverBase
{
protected:
  virtual ~nsMutationReceiver() { Disconnect(false); }

public:
  nsMutationReceiver(nsINode* aTarget, nsDOMMutationObserver* aObserver);

  nsMutationReceiver(nsINode* aRegisterTarget, nsMutationReceiverBase* aParent)
  : nsMutationReceiverBase(aRegisterTarget, aParent)
  {
    NS_ASSERTION(!static_cast<nsMutationReceiver*>(aParent)->GetParent(),
                 "Shouldn't create deep observer hierarchies!");
    aParent->AddClone(this);
  }

  nsMutationReceiver* GetParent()
  {
    return static_cast<nsMutationReceiver*>(mParent.get());
  }

  void RemoveClones()
  {
    for (int32_t i = 0; i < mTransientReceivers.Count(); ++i) {
      nsMutationReceiver* r =
        static_cast<nsMutationReceiver*>(mTransientReceivers[i]);
      r->DisconnectTransientReceiver();
    }
    mTransientReceivers.Clear();
  }

  void DisconnectTransientReceiver()
  {
    if (mRegisterTarget) {
      mRegisterTarget->RemoveMutationObserver(this);
      mRegisterTarget = nullptr;
    }

    mParent = nullptr;
    NS_ASSERTION(!mTarget, "Should not have mTarget");
    NS_ASSERTION(!mObserver, "Should not have mObserver");
  }

  void Disconnect(bool aRemoveFromObserver);

  NS_DECL_AND_IMPL_ZEROING_OPERATOR_NEW
  NS_DECL_ISUPPORTS

  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTEWILLCHANGE
  NS_DECL_NSIMUTATIONOBSERVER_CHARACTERDATAWILLCHANGE
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
  NS_DECL_NSIMUTATIONOBSERVER_NODEWILLBEDESTROYED

  virtual void AttributeSetToCurrentValue(nsIDocument* aDocument,
                                          mozilla::dom::Element* aElement,
                                          int32_t aNameSpaceID,
                                          nsIAtom* aAttribute) override
  {
    // We can reuse AttributeWillChange implementation.
    AttributeWillChange(aDocument, aElement, aNameSpaceID, aAttribute,
                        nsIDOMMutationEvent::MODIFICATION);
  }
};

#define NS_DOM_MUTATION_OBSERVER_IID \
{ 0x0c3b91f8, 0xcc3b, 0x4b08, \
  { 0x9e, 0xab, 0x07, 0x47, 0xa9, 0xe4, 0x65, 0xb4 } }

class nsDOMMutationObserver final : public nsISupports,
                                        public nsWrapperCache
{
public:
  nsDOMMutationObserver(already_AddRefed<nsPIDOMWindow>&& aOwner,
                        mozilla::dom::MutationCallback& aCb)
  : mOwner(aOwner), mLastPendingMutation(nullptr), mPendingMutationCount(0),
    mCallback(&aCb), mWaitingForRun(false), mId(++sCount)
  {
  }
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsDOMMutationObserver)
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_DOM_MUTATION_OBSERVER_IID)

  static already_AddRefed<nsDOMMutationObserver>
  Constructor(const mozilla::dom::GlobalObject& aGlobal,
              mozilla::dom::MutationCallback& aCb,
              mozilla::ErrorResult& aRv);

  virtual JSObject* WrapObject(JSContext* aCx) override
  {
    return mozilla::dom::MutationObserverBinding::Wrap(aCx, this);
  }

  nsISupports* GetParentObject() const
  {
    return mOwner;
  }

  void Observe(nsINode& aTarget,
               const mozilla::dom::MutationObserverInit& aOptions,
               mozilla::ErrorResult& aRv);

  void Disconnect();

  void TakeRecords(nsTArray<nsRefPtr<nsDOMMutationRecord> >& aRetVal);

  void HandleMutation();

  void GetObservingInfo(nsTArray<Nullable<MutationObservingInfo> >& aResult);

  mozilla::dom::MutationCallback* MutationCallback() { return mCallback; }

  void AppendMutationRecord(already_AddRefed<nsDOMMutationRecord> aRecord)
  {
    nsRefPtr<nsDOMMutationRecord> record = aRecord;
    MOZ_ASSERT(record);
    if (!mLastPendingMutation) {
      MOZ_ASSERT(!mFirstPendingMutation);
      mFirstPendingMutation = record.forget();
      mLastPendingMutation = mFirstPendingMutation;
    } else {
      MOZ_ASSERT(mFirstPendingMutation);
      mLastPendingMutation->mNext = record.forget();
      mLastPendingMutation = mLastPendingMutation->mNext;
    }
    ++mPendingMutationCount;
  }

  void ClearPendingRecords()
  {
    mFirstPendingMutation = nullptr;
    mLastPendingMutation = nullptr;
    mPendingMutationCount = 0;
  }

  // static methods
  static void HandleMutations()
  {
    if (sScheduledMutationObservers) {
      HandleMutationsInternal();
    }
  }

  static void EnterMutationHandling();
  static void LeaveMutationHandling();

  static void Shutdown();
protected:
  virtual ~nsDOMMutationObserver();

  friend class nsMutationReceiver;
  friend class nsAutoMutationBatch;
  nsMutationReceiver* GetReceiverFor(nsINode* aNode, bool aMayCreate);
  void RemoveReceiver(nsMutationReceiver* aReceiver);

  already_AddRefed<nsIVariant> TakeRecords();

  void GetAllSubtreeObserversFor(nsINode* aNode,
                                 nsTArray<nsMutationReceiver*>& aObservers);
  void ScheduleForRun();
  void RescheduleForRun();

  nsDOMMutationRecord* CurrentRecord(nsIAtom* aType);
  bool HasCurrentRecord(const nsAString& aType);

  bool Suppressed()
  {
    if (mOwner) {
      nsCOMPtr<nsIDocument> d = mOwner->GetExtantDoc();
      return d && d->IsInSyncOperation();
    }
    return false;
  }

  static void HandleMutationsInternal();

  static void AddCurrentlyHandlingObserver(nsDOMMutationObserver* aObserver);

  nsCOMPtr<nsPIDOMWindow>                            mOwner;

  nsCOMArray<nsMutationReceiver>                     mReceivers;
  nsClassHashtable<nsISupportsHashKey,
                   nsCOMArray<nsMutationReceiver> >  mTransientReceivers;
  // MutationRecords which are being constructed.
  nsAutoTArray<nsDOMMutationRecord*, 4>              mCurrentMutations;
  // MutationRecords which will be handed to the callback at the end of
  // the microtask.
  nsRefPtr<nsDOMMutationRecord>                      mFirstPendingMutation;
  nsDOMMutationRecord*                               mLastPendingMutation;
  uint32_t                                           mPendingMutationCount;

  nsRefPtr<mozilla::dom::MutationCallback>           mCallback;

  bool                                               mWaitingForRun;

  uint64_t                                           mId;

  static uint64_t                                    sCount;
  static nsAutoTArray<nsRefPtr<nsDOMMutationObserver>, 4>* sScheduledMutationObservers;
  static nsDOMMutationObserver*                      sCurrentObserver;

  static uint32_t                                    sMutationLevel;
  static nsAutoTArray<nsAutoTArray<nsRefPtr<nsDOMMutationObserver>, 4>, 4>*
                                                     sCurrentlyHandlingObservers;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsDOMMutationObserver, NS_DOM_MUTATION_OBSERVER_IID)

class nsAutoMutationBatch
{
public:
  nsAutoMutationBatch()
  : mPreviousBatch(nullptr), mBatchTarget(nullptr), mRemovalDone(false),
    mFromFirstToLast(false), mAllowNestedBatches(false)    
  {
  }

  nsAutoMutationBatch(nsINode* aTarget, bool aFromFirstToLast,
                      bool aAllowNestedBatches)
  : mPreviousBatch(nullptr), mBatchTarget(nullptr), mRemovalDone(false),
    mFromFirstToLast(false), mAllowNestedBatches(false)
  {
    Init(aTarget, aFromFirstToLast, aAllowNestedBatches);
  }

  void Init(nsINode* aTarget, bool aFromFirstToLast, bool aAllowNestedBatches)
  {
    if (aTarget && aTarget->OwnerDoc()->MayHaveDOMMutationObservers()) {
      if (sCurrentBatch && !sCurrentBatch->mAllowNestedBatches) {
        return;
      }
      mBatchTarget = aTarget;
      mFromFirstToLast = aFromFirstToLast;
      mAllowNestedBatches = aAllowNestedBatches;
      mPreviousBatch = sCurrentBatch;
      sCurrentBatch = this;
      nsDOMMutationObserver::EnterMutationHandling();
    }
  }

  void RemovalDone() { mRemovalDone = true; }
  static bool IsRemovalDone() { return sCurrentBatch->mRemovalDone; }

  void SetPrevSibling(nsINode* aNode) { mPrevSibling = aNode; }
  void SetNextSibling(nsINode* aNode) { mNextSibling = aNode; }

  void Done();

  ~nsAutoMutationBatch() { NodesAdded(); }

  static bool IsBatching()
  {
    return !!sCurrentBatch;
  }

  static nsAutoMutationBatch* GetCurrentBatch()
  {
    return sCurrentBatch;
  }

  static void UpdateObserver(nsDOMMutationObserver* aObserver,
                             bool aWantsChildList)
  {
    uint32_t l = sCurrentBatch->mObservers.Length();
    for (uint32_t i = 0; i < l; ++i) {
      if (sCurrentBatch->mObservers[i].mObserver == aObserver) {
        if (aWantsChildList) {
          sCurrentBatch->mObservers[i].mWantsChildList = aWantsChildList;
        } 
        return;
      }
    }
    BatchObserver* bo = sCurrentBatch->mObservers.AppendElement(); 
    bo->mObserver = aObserver;
    bo->mWantsChildList = aWantsChildList;
  }


  static nsINode* GetBatchTarget() { return sCurrentBatch->mBatchTarget; }

  // Mutation receivers notify the batch about removed child nodes.
  static void NodeRemoved(nsIContent* aChild)
  {
    if (IsBatching() && !sCurrentBatch->mRemovalDone) {
      uint32_t len = sCurrentBatch->mRemovedNodes.Length();
      if (!len ||
          sCurrentBatch->mRemovedNodes[len - 1] != aChild) {
        sCurrentBatch->mRemovedNodes.AppendElement(aChild);
      }
    }
  }

  // Called after new child nodes have been added to the batch target.
  void NodesAdded()
  {
    if (sCurrentBatch != this) {
      return;
    }

    nsIContent* c =
      mPrevSibling ? mPrevSibling->GetNextSibling() :
                     mBatchTarget->GetFirstChild();
    for (; c != mNextSibling; c = c->GetNextSibling()) {
      mAddedNodes.AppendElement(c);
    }
    Done();
  }

private:
  struct BatchObserver
  {
    nsDOMMutationObserver* mObserver;
    bool                   mWantsChildList;
  };
  
  static nsAutoMutationBatch* sCurrentBatch;
  nsAutoMutationBatch* mPreviousBatch;
  nsAutoTArray<BatchObserver, 2> mObservers;
  nsTArray<nsCOMPtr<nsIContent> > mRemovedNodes;
  nsTArray<nsCOMPtr<nsIContent> > mAddedNodes;
  nsINode* mBatchTarget;
  bool mRemovalDone;
  bool mFromFirstToLast;
  bool mAllowNestedBatches;
  nsCOMPtr<nsINode> mPrevSibling;
  nsCOMPtr<nsINode> mNextSibling;
};

inline
nsDOMMutationObserver*
nsMutationReceiverBase::Observer()
{
  return mParent ?
    mParent->Observer() : static_cast<nsDOMMutationObserver*>(mObserver);
}

#endif