dom/svg/SVGUseElement.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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/dom/SVGUseElement.h"
   8
   9 #include "mozilla/ArrayUtils.h"
  10 #include "mozilla/ErrorResult.h"
  11 #include "mozilla/ScopeExit.h"
  12 #include "mozilla/StaticPrefs_svg.h"
  13 #include "mozilla/SVGObserverUtils.h"
  14 #include "mozilla/SVGUseFrame.h"
  15 #include "mozilla/URLExtraData.h"
  16 #include "mozilla/dom/Document.h"
  17 #include "mozilla/dom/ReferrerInfo.h"
  18 #include "mozilla/dom/ShadowIncludingTreeIterator.h"
  19 #include "mozilla/dom/SVGGraphicsElement.h"
  20 #include "mozilla/dom/SVGLengthBinding.h"
  21 #include "mozilla/dom/SVGSVGElement.h"
  22 #include "mozilla/dom/SVGSymbolElement.h"
  23 #include "mozilla/dom/SVGUseElementBinding.h"
  24 #include "nsGkAtoms.h"
  25 #include "nsContentUtils.h"
  26 #include "nsIReferrerInfo.h"
  27 #include "nsIURI.h"
  28 #include "SVGGeometryProperty.h"
  29
  30 NS_IMPL_NS_NEW_SVG_ELEMENT(Use)
  31
  32 namespace mozilla::dom {
  33
  34 JSObject* SVGUseElement::WrapNode(JSContext* aCx,
  35                                   JS::Handle<JSObject*> aGivenProto) {
  36   return SVGUseElement_Binding::Wrap(aCx, this, aGivenProto);
  37 }
  38
  39 ////////////////////////////////////////////////////////////////////////
  40 // implementation
  41
  42 SVGElement::LengthInfo SVGUseElement::sLengthInfo[4] = {
  43     {nsGkAtoms::x, 0, SVGLength_Binding::SVG_LENGTHTYPE_NUMBER,
  44      SVGContentUtils::X},
  45     {nsGkAtoms::y, 0, SVGLength_Binding::SVG_LENGTHTYPE_NUMBER,
  46      SVGContentUtils::Y},
  47     {nsGkAtoms::width, 0, SVGLength_Binding::SVG_LENGTHTYPE_NUMBER,
  48      SVGContentUtils::X},
  49     {nsGkAtoms::height, 0, SVGLength_Binding::SVG_LENGTHTYPE_NUMBER,
  50      SVGContentUtils::Y},
  51 };
  52
  53 SVGElement::StringInfo SVGUseElement::sStringInfo[2] = {
  54     {nsGkAtoms::href, kNameSpaceID_None, true},
  55     {nsGkAtoms::href, kNameSpaceID_XLink, true}};
  56
  57 //----------------------------------------------------------------------
  58 // nsISupports methods
  59
  60 NS_IMPL_CYCLE_COLLECTION_CLASS(SVGUseElement)
  61
  62 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(SVGUseElement,
  63                                                 SVGUseElementBase)
  64   NS_IMPL_CYCLE_COLLECTION_UNLINK(mOriginal)
  65   tmp->UnlinkSource();
  66 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  67 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(SVGUseElement,
  68                                                   SVGUseElementBase)
  69   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOriginal)
  70   tmp->mReferencedElementTracker.Traverse(&cb);
  71 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  72
  73 NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED(SVGUseElement, SVGUseElementBase,
  74                                              nsIMutationObserver)
  75
  76 //----------------------------------------------------------------------
  77 // Implementation
  78
  79 SVGUseElement::SVGUseElement(
  80     already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
  81     : SVGUseElementBase(std::move(aNodeInfo)), mReferencedElementTracker(this) {
  82   SetEnabledCallbacks(kCharacterDataChanged | kAttributeChanged |
  83                       kContentAppended | kContentInserted | kContentRemoved |
  84                       kNodeWillBeDestroyed);
  85 }
  86
  87 SVGUseElement::~SVGUseElement() {
  88   UnlinkSource();
  89   MOZ_DIAGNOSTIC_ASSERT(!OwnerDoc()->SVGUseElementNeedsShadowTreeUpdate(*this),
  90                         "Dying without unbinding?");
  91 }
  92
  93 namespace SVGT = SVGGeometryProperty::Tags;
  94
  95 //----------------------------------------------------------------------
  96 // nsINode methods
  97
  98 void SVGUseElement::ProcessAttributeChange(int32_t aNamespaceID,
  99                                            nsAtom* aAttribute) {
 100   if (OwnerDoc()->CloningForSVGUse()) {
 101     return;
 102   }
 103   if (aNamespaceID == kNameSpaceID_None) {
 104     if (aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height) {
 105       const bool hadValidDimensions = HasValidDimensions();
 106       const bool isUsed = OurWidthAndHeightAreUsed();
 107       if (isUsed) {
 108         SyncWidthOrHeight(aAttribute);
 109       }
 110
 111       if (auto* frame = GetFrame()) {
 112         frame->DimensionAttributeChanged(hadValidDimensions, isUsed);
 113       }
 114     }
 115   }
 116
 117   if ((aNamespaceID == kNameSpaceID_XLink ||
 118        aNamespaceID == kNameSpaceID_None) &&
 119       aAttribute == nsGkAtoms::href) {
 120     // We're changing our nature, clear out the clone information.
 121     if (auto* frame = GetFrame()) {
 122       frame->HrefChanged();
 123     }
 124     UnlinkSource();
 125     TriggerReclone();
 126   }
 127 }
 128
 129 void SVGUseElement::AfterSetAttr(int32_t aNamespaceID, nsAtom* aAttribute,
 130                                  const nsAttrValue* aValue,
 131                                  const nsAttrValue* aOldValue,
 132                                  nsIPrincipal* aSubjectPrincipal,
 133                                  bool aNotify) {
 134   ProcessAttributeChange(aNamespaceID, aAttribute);
 135   return SVGUseElementBase::AfterSetAttr(aNamespaceID, aAttribute, aValue,
 136                                          aOldValue, aSubjectPrincipal, aNotify);
 137 }
 138
 139 nsresult SVGUseElement::Clone(dom::NodeInfo* aNodeInfo,
 140                               nsINode** aResult) const {
 141   *aResult = nullptr;
 142   SVGUseElement* it =
 143       new (aNodeInfo->NodeInfoManager()) SVGUseElement(do_AddRef(aNodeInfo));
 144
 145   nsCOMPtr<nsINode> kungFuDeathGrip(it);
 146   nsresult rv1 = it->Init();
 147   nsresult rv2 = const_cast<SVGUseElement*>(this)->CopyInnerTo(it);
 148
 149   if (aNodeInfo->GetDocument()->CloningForSVGUse()) {
 150     // SVGUseElement specific portion - record who we cloned from
 151     it->mOriginal = const_cast<SVGUseElement*>(this);
 152   }
 153
 154   if (NS_SUCCEEDED(rv1) && NS_SUCCEEDED(rv2)) {
 155     kungFuDeathGrip.swap(*aResult);
 156   }
 157
 158   return NS_FAILED(rv1) ? rv1 : rv2;
 159 }
 160
 161 nsresult SVGUseElement::BindToTree(BindContext& aContext, nsINode& aParent) {
 162   nsresult rv = SVGUseElementBase::BindToTree(aContext, aParent);
 163   NS_ENSURE_SUCCESS(rv, rv);
 164
 165   TriggerReclone();
 166   return NS_OK;
 167 }
 168
 169 void SVGUseElement::UnbindFromTree(bool aNullParent) {
 170   SVGUseElementBase::UnbindFromTree(aNullParent);
 171   OwnerDoc()->UnscheduleSVGUseElementShadowTreeUpdate(*this);
 172 }
 173
 174 already_AddRefed<DOMSVGAnimatedString> SVGUseElement::Href() {
 175   return mStringAttributes[HREF].IsExplicitlySet()
 176              ? mStringAttributes[HREF].ToDOMAnimatedString(this)
 177              : mStringAttributes[XLINK_HREF].ToDOMAnimatedString(this);
 178 }
 179
 180 //----------------------------------------------------------------------
 181
 182 already_AddRefed<DOMSVGAnimatedLength> SVGUseElement::X() {
 183   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 184 }
 185
 186 already_AddRefed<DOMSVGAnimatedLength> SVGUseElement::Y() {
 187   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 188 }
 189
 190 already_AddRefed<DOMSVGAnimatedLength> SVGUseElement::Width() {
 191   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 192 }
 193
 194 already_AddRefed<DOMSVGAnimatedLength> SVGUseElement::Height() {
 195   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 196 }
 197
 198 //----------------------------------------------------------------------
 199 // nsIMutationObserver methods
 200
 201 void SVGUseElement::CharacterDataChanged(nsIContent* aContent,
 202                                          const CharacterDataChangeInfo&) {
 203   if (nsContentUtils::IsInSameAnonymousTree(mReferencedElementTracker.get(),
 204                                             aContent)) {
 205     TriggerReclone();
 206   }
 207 }
 208
 209 void SVGUseElement::AttributeChanged(Element* aElement, int32_t aNamespaceID,
 210                                      nsAtom* aAttribute, int32_t aModType,
 211                                      const nsAttrValue* aOldValue) {
 212   if (nsContentUtils::IsInSameAnonymousTree(mReferencedElementTracker.get(),
 213                                             aElement)) {
 214     TriggerReclone();
 215   }
 216 }
 217
 218 void SVGUseElement::ContentAppended(nsIContent* aFirstNewContent) {
 219   // FIXME(emilio, bug 1442336): Why does this check the parent but
 220   // ContentInserted the child?
 221   if (nsContentUtils::IsInSameAnonymousTree(mReferencedElementTracker.get(),
 222                                             aFirstNewContent->GetParent())) {
 223     TriggerReclone();
 224   }
 225 }
 226
 227 void SVGUseElement::ContentInserted(nsIContent* aChild) {
 228   // FIXME(emilio, bug 1442336): Why does this check the child but
 229   // ContentAppended the parent?
 230   if (nsContentUtils::IsInSameAnonymousTree(mReferencedElementTracker.get(),
 231                                             aChild)) {
 232     TriggerReclone();
 233   }
 234 }
 235
 236 void SVGUseElement::ContentRemoved(nsIContent* aChild,
 237                                    nsIContent* aPreviousSibling) {
 238   if (nsContentUtils::IsInSameAnonymousTree(mReferencedElementTracker.get(),
 239                                             aChild)) {
 240     TriggerReclone();
 241   }
 242 }
 243
 244 void SVGUseElement::NodeWillBeDestroyed(nsINode* aNode) {
 245   nsCOMPtr<nsIMutationObserver> kungFuDeathGrip(this);
 246   UnlinkSource();
 247 }
 248
 249 // Returns whether this node could ever be displayed.
 250 static bool NodeCouldBeRendered(const nsINode& aNode) {
 251   if (const auto* symbol = SVGSymbolElement::FromNode(aNode)) {
 252     return symbol->CouldBeRendered();
 253   }
 254   // TODO: Do we have other cases we can optimize out easily?
 255   return true;
 256 }
 257
 258 // <svg:use> can be used (no pun intended) to trivially cause an explosion of
 259 // clones that could potentially DoS the browser. We have a configurable limit
 260 // to control this.
 261 static bool IsTooMuchRecursion(uint32_t aCount) {
 262   switch (StaticPrefs::svg_use_element_recursive_clone_limit_enabled()) {
 263     case 0:
 264       return false;
 265     case 1:
 266       break;
 267     default:
 268       if (!XRE_IsParentProcess()) {
 269         return false;
 270       }
 271       break;
 272   }
 273   return aCount >= StaticPrefs::svg_use_element_recursive_clone_limit();
 274 }
 275
 276 // Circular loop detection, plus detection of whether this shadow tree is
 277 // rendered at all.
 278 auto SVGUseElement::ScanAncestors(const Element& aTarget) const -> ScanResult {
 279   uint32_t count = 0;
 280   return ScanAncestorsInternal(aTarget, count);
 281 }
 282
 283 auto SVGUseElement::ScanAncestorsInternal(const Element& aTarget,
 284                                           uint32_t& aCount) const
 285     -> ScanResult {
 286   if (&aTarget == this) {
 287     return ScanResult::CyclicReference;
 288   }
 289   if (mOriginal) {
 290     if (IsTooMuchRecursion(++aCount)) {
 291       return ScanResult::TooDeep;
 292     }
 293     auto result = mOriginal->ScanAncestorsInternal(aTarget, aCount);
 294     switch (result) {
 295       case ScanResult::TooDeep:
 296       case ScanResult::CyclicReference:
 297         return result;
 298       case ScanResult::Ok:
 299       case ScanResult::Invisible:
 300         break;
 301     }
 302   }
 303
 304   auto result = ScanResult::Ok;
 305   for (nsINode* parent = GetParentOrShadowHostNode(); parent;
 306        parent = parent->GetParentOrShadowHostNode()) {
 307     if (parent == &aTarget) {
 308       return ScanResult::CyclicReference;
 309     }
 310     if (auto* use = SVGUseElement::FromNode(*parent)) {
 311       if (IsTooMuchRecursion(++aCount)) {
 312         return ScanResult::TooDeep;
 313       }
 314       if (mOriginal && use->mOriginal == mOriginal) {
 315         return ScanResult::CyclicReference;
 316       }
 317     }
 318     // Do we have other similar cases we can optimize out easily?
 319     if (!NodeCouldBeRendered(*parent)) {
 320       // NOTE(emilio): We can't just return here. If we're cyclic, we need to
 321       // know.
 322       result = ScanResult::Invisible;
 323     }
 324   }
 325   return result;
 326 }
 327
 328 //----------------------------------------------------------------------
 329
 330 static bool IsForbiddenUseNode(const nsINode& aNode) {
 331   if (!aNode.IsElement()) {
 332     return false;
 333   }
 334   const auto* svg = SVGElement::FromNode(aNode);
 335   return !svg || !svg->IsSVGGraphicsElement();
 336 }
 337
 338 static void CollectForbiddenNodes(Element& aRoot,
 339                                   nsTArray<RefPtr<nsINode>>& aNodes) {
 340   auto iter = dom::ShadowIncludingTreeIterator(aRoot);
 341   while (iter) {
 342     nsINode* node = *iter;
 343     if (IsForbiddenUseNode(*node)) {
 344       aNodes.AppendElement(node);
 345       iter.SkipChildren();
 346       continue;
 347     }
 348     ++iter;
 349   }
 350 }
 351
 352 // SVG1 restricted <use> trees to SVGGraphicsElements.
 353 // https://www.w3.org/TR/SVG11/struct.html#UseElement:
 354 //
 355 //    Any ‘svg’, ‘symbol’, ‘g’, graphics element or other ‘use’ is potentially a
 356 //    template object that can be re-used (i.e., "instanced") in the SVG
 357 //    document via a ‘use’ element. The ‘use’ element references another element
 358 //    and indicates that the graphical contents of that element is
 359 //    included/drawn at that given point in the document.
 360 //
 361 // SVG2 doesn't have that same restriction.
 362 // https://www.w3.org/TR/SVG2/struct.html#UseShadowTree:
 363 //
 364 //    Previous versions of SVG restricted the contents of the shadow tree to SVG
 365 //    graphics elements. This specification allows any valid SVG document
 366 //    subtree to be cloned. Cloning non-graphical content, however, will not
 367 //    usually have any visible effect.
 368 //
 369 // But it's pretty ambiguous as to what the behavior should be for some
 370 // elements, because <script> is inert, but <iframe> is not, see:
 371 // https://github.com/w3c/svgwg/issues/876
 372 //
 373 // So, fairly confusing, all-in-all.
 374 static void RemoveForbiddenNodes(Element& aRoot, bool aIsCrossDocument) {
 375   switch (StaticPrefs::svg_use_element_graphics_element_restrictions()) {
 376     case 0:
 377       return;
 378     case 1:
 379       if (!aIsCrossDocument) {
 380         return;
 381       }
 382       break;
 383     default:
 384       break;
 385   }
 386
 387   AutoTArray<RefPtr<nsINode>, 10> unsafeNodes;
 388   CollectForbiddenNodes(aRoot, unsafeNodes);
 389   for (auto& unsafeNode : unsafeNodes) {
 390     unsafeNode->Remove();
 391   }
 392 }
 393
 394 void SVGUseElement::UpdateShadowTree() {
 395   MOZ_ASSERT(IsInComposedDoc());
 396
 397   if (mReferencedElementTracker.get()) {
 398     mReferencedElementTracker.get()->RemoveMutationObserver(this);
 399   }
 400
 401   LookupHref();
 402
 403   RefPtr<ShadowRoot> shadow = GetShadowRoot();
 404   if (!shadow) {
 405     shadow = AttachShadowWithoutNameChecks(ShadowRootMode::Closed);
 406   }
 407   MOZ_ASSERT(shadow);
 408
 409   auto* targetElement =
 410       SVGGraphicsElement::FromNodeOrNull(mReferencedElementTracker.get());
 411   RefPtr<Element> newElement;
 412
 413   auto UpdateShadowTree = mozilla::MakeScopeExit([&]() {
 414     if (nsIContent* firstChild = shadow->GetFirstChild()) {
 415       MOZ_ASSERT(!firstChild->GetNextSibling());
 416       shadow->RemoveChildNode(firstChild, /* aNotify = */ true);
 417     }
 418
 419     if (newElement) {
 420       shadow->AppendChildTo(newElement, /* aNotify = */ true, IgnoreErrors());
 421     }
 422   });
 423
 424   // make sure target is valid type for <use>
 425   if (!targetElement) {
 426     return;
 427   }
 428
 429   if (ScanAncestors(*targetElement) != ScanResult::Ok) {
 430     return;
 431   }
 432
 433   nsCOMPtr<nsIURI> baseURI = targetElement->GetBaseURI();
 434   if (!baseURI) {
 435     return;
 436   }
 437
 438   {
 439     const bool isCrossDocument = targetElement->OwnerDoc() != OwnerDoc();
 440
 441     nsNodeInfoManager* nodeInfoManager =
 442         isCrossDocument ? OwnerDoc()->NodeInfoManager() : nullptr;
 443
 444     nsCOMPtr<nsINode> newNode =
 445         targetElement->Clone(true, nodeInfoManager, IgnoreErrors());
 446     if (!newNode) {
 447       return;
 448     }
 449
 450     MOZ_ASSERT(newNode->IsElement());
 451     newElement = newNode.forget().downcast<Element>();
 452     RemoveForbiddenNodes(*newElement, isCrossDocument);
 453   }
 454
 455   if (newElement->IsAnyOfSVGElements(nsGkAtoms::svg, nsGkAtoms::symbol)) {
 456     auto* newSVGElement = static_cast<SVGElement*>(newElement.get());
 457     if (mLengthAttributes[ATTR_WIDTH].IsExplicitlySet())
 458       newSVGElement->SetLength(nsGkAtoms::width, mLengthAttributes[ATTR_WIDTH]);
 459     if (mLengthAttributes[ATTR_HEIGHT].IsExplicitlySet())
 460       newSVGElement->SetLength(nsGkAtoms::height,
 461                                mLengthAttributes[ATTR_HEIGHT]);
 462   }
 463
 464   // Bug 1415044 the specs do not say which referrer information we should use.
 465   // This may change if there's any spec comes out.
 466   auto referrerInfo = MakeRefPtr<ReferrerInfo>(*this);
 467   mContentURLData = new URLExtraData(baseURI.forget(), referrerInfo.forget(),
 468                                      do_AddRef(NodePrincipal()));
 469
 470   targetElement->AddMutationObserver(this);
 471 }
 472
 473 nsIURI* SVGUseElement::GetSourceDocURI() {
 474   nsIContent* targetElement = mReferencedElementTracker.get();
 475   if (!targetElement) {
 476     return nullptr;
 477   }
 478
 479   return targetElement->OwnerDoc()->GetDocumentURI();
 480 }
 481
 482 const Encoding* SVGUseElement::GetSourceDocCharacterSet() {
 483   nsIContent* targetElement = mReferencedElementTracker.get();
 484   if (!targetElement) {
 485     return nullptr;
 486   }
 487
 488   return targetElement->OwnerDoc()->GetDocumentCharacterSet();
 489 }
 490
 491 static nsINode* GetClonedChild(const SVGUseElement& aUseElement) {
 492   const ShadowRoot* shadow = aUseElement.GetShadowRoot();
 493   return shadow ? shadow->GetFirstChild() : nullptr;
 494 }
 495
 496 bool SVGUseElement::OurWidthAndHeightAreUsed() const {
 497   nsINode* clonedChild = GetClonedChild(*this);
 498   return clonedChild &&
 499          clonedChild->IsAnyOfSVGElements(nsGkAtoms::svg, nsGkAtoms::symbol);
 500 }
 501
 502 //----------------------------------------------------------------------
 503 // implementation helpers
 504
 505 void SVGUseElement::SyncWidthOrHeight(nsAtom* aName) {
 506   NS_ASSERTION(aName == nsGkAtoms::width || aName == nsGkAtoms::height,
 507                "The clue is in the function name");
 508   NS_ASSERTION(OurWidthAndHeightAreUsed(), "Don't call this");
 509
 510   if (!OurWidthAndHeightAreUsed()) {
 511     return;
 512   }
 513
 514   auto* target = SVGElement::FromNode(GetClonedChild(*this));
 515   uint32_t index =
 516       sLengthInfo[ATTR_WIDTH].mName == aName ? ATTR_WIDTH : ATTR_HEIGHT;
 517
 518   if (mLengthAttributes[index].IsExplicitlySet()) {
 519     target->SetLength(aName, mLengthAttributes[index]);
 520     return;
 521   }
 522   if (target->IsSVGElement(nsGkAtoms::svg)) {
 523     // Our width/height attribute is now no longer explicitly set, so we
 524     // need to revert the clone's width/height to the width/height of the
 525     // content that's being cloned.
 526     TriggerReclone();
 527     return;
 528   }
 529   // Our width/height attribute is now no longer explicitly set, so we
 530   // need to set the value to 100%
 531   SVGAnimatedLength length;
 532   length.Init(SVGContentUtils::XY, 0xff, 100,
 533               SVGLength_Binding::SVG_LENGTHTYPE_PERCENTAGE);
 534   target->SetLength(aName, length);
 535 }
 536
 537 void SVGUseElement::LookupHref() {
 538   nsAutoString href;
 539   if (mStringAttributes[HREF].IsExplicitlySet()) {
 540     mStringAttributes[HREF].GetAnimValue(href, this);
 541   } else {
 542     mStringAttributes[XLINK_HREF].GetAnimValue(href, this);
 543   }
 544
 545   if (href.IsEmpty()) {
 546     return;
 547   }
 548
 549   Element* treeToWatch = mOriginal ? mOriginal.get() : this;
 550   if (nsContentUtils::IsLocalRefURL(href)) {
 551     mReferencedElementTracker.ResetWithLocalRef(*treeToWatch, href);
 552     return;
 553   }
 554
 555   nsCOMPtr<nsIURI> baseURI = treeToWatch->GetBaseURI();
 556   nsCOMPtr<nsIURI> targetURI;
 557   nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(targetURI), href,
 558                                             GetComposedDoc(), baseURI);
 559   if (!targetURI) {
 560     return;
 561   }
 562
 563   // Don't allow <use href="data:...">. Using "#ref" inside a data: document is
 564   // handled above.
 565   if (targetURI->SchemeIs("data") &&
 566       !StaticPrefs::svg_use_element_data_url_href_allowed()) {
 567     return;
 568   }
 569
 570   nsIReferrerInfo* referrer =
 571       OwnerDoc()->ReferrerInfoForInternalCSSAndSVGResources();
 572   mReferencedElementTracker.ResetToURIFragmentID(treeToWatch, targetURI,
 573                                                  referrer);
 574 }
 575
 576 void SVGUseElement::TriggerReclone() {
 577   if (Document* doc = GetComposedDoc()) {
 578     doc->ScheduleSVGUseElementShadowTreeUpdate(*this);
 579   }
 580 }
 581
 582 void SVGUseElement::UnlinkSource() {
 583   if (mReferencedElementTracker.get()) {
 584     mReferencedElementTracker.get()->RemoveMutationObserver(this);
 585   }
 586   mReferencedElementTracker.Unlink();
 587 }
 588
 589 //----------------------------------------------------------------------
 590 // SVGElement methods
 591
 592 /* virtual */
 593 gfxMatrix SVGUseElement::PrependLocalTransformsTo(
 594     const gfxMatrix& aMatrix, SVGTransformTypes aWhich) const {
 595   // 'transform' attribute:
 596   gfxMatrix userToParent;
 597
 598   if (aWhich == eUserSpaceToParent || aWhich == eAllTransforms) {
 599     userToParent = GetUserToParentTransform(mAnimateMotionTransform.get(),
 600                                             mTransforms.get());
 601     if (aWhich == eUserSpaceToParent) {
 602       return userToParent * aMatrix;
 603     }
 604   }
 605
 606   // our 'x' and 'y' attributes:
 607   float x, y;
 608   if (!SVGGeometryProperty::ResolveAll<SVGT::X, SVGT::Y>(this, &x, &y)) {
 609     const_cast<SVGUseElement*>(this)->GetAnimatedLengthValues(&x, &y, nullptr);
 610   }
 611
 612   gfxMatrix childToUser = gfxMatrix::Translation(x, y);
 613
 614   if (aWhich == eAllTransforms) {
 615     return childToUser * userToParent * aMatrix;
 616   }
 617
 618   MOZ_ASSERT(aWhich == eChildToUserSpace, "Unknown TransformTypes");
 619
 620   // The following may look broken because pre-multiplying our eChildToUserSpace
 621   // transform with another matrix without including our eUserSpaceToParent
 622   // transform between the two wouldn't make sense.  We don't expect that to
 623   // ever happen though.  We get here either when the identity matrix has been
 624   // passed because our caller just wants our eChildToUserSpace transform, or
 625   // when our eUserSpaceToParent transform has already been multiplied into the
 626   // matrix that our caller passes (such as when we're called from PaintSVG).
 627   return childToUser * aMatrix;
 628 }
 629
 630 /* virtual */
 631 bool SVGUseElement::HasValidDimensions() const {
 632   if (!OurWidthAndHeightAreUsed()) {
 633     return true;
 634   }
 635
 636   return (!mLengthAttributes[ATTR_WIDTH].IsExplicitlySet() ||
 637           mLengthAttributes[ATTR_WIDTH].GetAnimValInSpecifiedUnits() > 0) &&
 638          (!mLengthAttributes[ATTR_HEIGHT].IsExplicitlySet() ||
 639           mLengthAttributes[ATTR_HEIGHT].GetAnimValInSpecifiedUnits() > 0);
 640 }
 641
 642 SVGElement::LengthAttributesInfo SVGUseElement::GetLengthInfo() {
 643   return LengthAttributesInfo(mLengthAttributes, sLengthInfo,
 644                               ArrayLength(sLengthInfo));
 645 }
 646
 647 SVGElement::StringAttributesInfo SVGUseElement::GetStringInfo() {
 648   return StringAttributesInfo(mStringAttributes, sStringInfo,
 649                               ArrayLength(sStringInfo));
 650 }
 651
 652 SVGUseFrame* SVGUseElement::GetFrame() const {
 653   nsIFrame* frame = GetPrimaryFrame();
 654   // We might be a plain SVGContainerFrame if we didn't pass the conditional
 655   // processing checks.
 656   if (!frame || !frame->IsSVGUseFrame()) {
 657     MOZ_ASSERT_IF(frame, frame->Type() == LayoutFrameType::None);
 658     return nullptr;
 659   }
 660   return static_cast<SVGUseFrame*>(frame);
 661 }
 662
 663 //----------------------------------------------------------------------
 664 // nsIContent methods
 665
 666 NS_IMETHODIMP_(bool)
 667 SVGUseElement::IsAttributeMapped(const nsAtom* name) const {
 668   return name == nsGkAtoms::x || name == nsGkAtoms::y ||
 669          SVGUseElementBase::IsAttributeMapped(name);
 670 }
 671
 672 nsCSSPropertyID SVGUseElement::GetCSSPropertyIdForAttrEnum(uint8_t aAttrEnum) {
 673   switch (aAttrEnum) {
 674     case ATTR_X:
 675       return eCSSProperty_x;
 676     case ATTR_Y:
 677       return eCSSProperty_y;
 678     default:
 679       // Currently we don't map width or height to style
 680       return eCSSProperty_UNKNOWN;
 681   }
 682 }
 683
 684 }  // namespace mozilla::dom