[ tor-browser ].git.dasho

HTMLLinkElement.cpp (25311B)
      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/HTMLLinkElement.h"
      8 
      9 #include "DecoderDoctorDiagnostics.h"
     10 #include "DecoderTraits.h"
     11 #include "MediaContainerType.h"
     12 #include "MediaList.h"
     13 #include "imgLoader.h"
     14 #include "mozilla/AsyncEventDispatcher.h"
     15 #include "mozilla/Components.h"
     16 #include "mozilla/EventDispatcher.h"
     17 #include "mozilla/Preferences.h"
     18 #include "mozilla/StaticPrefs_dom.h"
     19 #include "mozilla/StaticPrefs_network.h"
     20 #include "mozilla/dom/BindContext.h"
     21 #include "mozilla/dom/Document.h"
     22 #include "mozilla/dom/DocumentInlines.h"
     23 #include "mozilla/dom/HTMLDNSPrefetch.h"
     24 #include "mozilla/dom/HTMLLinkElementBinding.h"
     25 #include "mozilla/dom/ReferrerInfo.h"
     26 #include "mozilla/dom/ScriptLoader.h"
     27 #include "nsAttrValueInlines.h"
     28 #include "nsAttrValueOrString.h"
     29 #include "nsContentUtils.h"
     30 #include "nsDOMTokenList.h"
     31 #include "nsGenericHTMLElement.h"
     32 #include "nsGkAtoms.h"
     33 #include "nsIContentInlines.h"
     34 #include "nsIContentPolicy.h"
     35 #include "nsINode.h"
     36 #include "nsIPrefetchService.h"
     37 #include "nsMimeTypes.h"
     38 #include "nsPIDOMWindow.h"
     39 #include "nsReadableUtils.h"
     40 #include "nsStyleConsts.h"
     41 #include "nsUnicharUtils.h"
     42 #include "nsWindowSizes.h"
     43 
     44 NS_IMPL_NS_NEW_HTML_ELEMENT(Link)
     45 
     46 namespace mozilla::dom {
     47 
     48 HTMLLinkElement::HTMLLinkElement(
     49    already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
     50    : nsGenericHTMLElement(std::move(aNodeInfo)) {}
     51 
     52 HTMLLinkElement::~HTMLLinkElement() { SupportsDNSPrefetch::Destroyed(*this); }
     53 
     54 NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLLinkElement)
     55 
     56 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(HTMLLinkElement,
     57                                                  nsGenericHTMLElement)
     58  tmp->LinkStyle::Traverse(cb);
     59  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRelList)
     60  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSizes)
     61  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mBlocking)
     62 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
     63 
     64 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(HTMLLinkElement,
     65                                                nsGenericHTMLElement)
     66  tmp->LinkStyle::Unlink();
     67  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRelList)
     68  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSizes)
     69  NS_IMPL_CYCLE_COLLECTION_UNLINK(mBlocking)
     70 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
     71 
     72 NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(HTMLLinkElement,
     73                                               nsGenericHTMLElement)
     74 
     75 NS_IMPL_ELEMENT_CLONE(HTMLLinkElement)
     76 
     77 bool HTMLLinkElement::Disabled() const {
     78  return GetBoolAttr(nsGkAtoms::disabled);
     79 }
     80 
     81 void HTMLLinkElement::SetDisabled(bool aDisabled, ErrorResult& aRv) {
     82  return SetHTMLBoolAttr(nsGkAtoms::disabled, aDisabled, aRv);
     83 }
     84 
     85 nsresult HTMLLinkElement::BindToTree(BindContext& aContext, nsINode& aParent) {
     86  nsresult rv = nsGenericHTMLElement::BindToTree(aContext, aParent);
     87  NS_ENSURE_SUCCESS(rv, rv);
     88 
     89  if (IsInComposedDoc()) {
     90    TryDNSPrefetchOrPreconnectOrPrefetchOrPreloadOrPrerender();
     91  }
     92 
     93  LinkStyle::BindToTree();
     94 
     95  if (IsInUncomposedDoc()) {
     96    if (AttrValueIs(kNameSpaceID_None, nsGkAtoms::rel, nsGkAtoms::localization,
     97                    eIgnoreCase)) {
     98      aContext.OwnerDoc().LocalizationLinkAdded(this);
     99    }
    100 
    101    LinkAdded();
    102  }
    103 
    104  return rv;
    105 }
    106 
    107 void HTMLLinkElement::LinkAdded() {
    108  CreateAndDispatchEvent(u"DOMLinkAdded"_ns);
    109 }
    110 
    111 void HTMLLinkElement::UnbindFromTree(UnbindContext& aContext) {
    112  CancelDNSPrefetch(*this);
    113  CancelPrefetchOrPreload();
    114 
    115  // If this is reinserted back into the document it will not be
    116  // from the parser.
    117  Document* oldDoc = GetUncomposedDoc();
    118  ShadowRoot* oldShadowRoot = GetContainingShadow();
    119 
    120  // We want to update the localization but only if the link is removed from a
    121  // DOM change, and not because the document is going away.
    122  bool ignore;
    123  if (oldDoc) {
    124    if (oldDoc->GetScriptHandlingObject(ignore) &&
    125        AttrValueIs(kNameSpaceID_None, nsGkAtoms::rel, nsGkAtoms::localization,
    126                    eIgnoreCase)) {
    127      oldDoc->LocalizationLinkRemoved(this);
    128    }
    129  }
    130 
    131  nsGenericHTMLElement::UnbindFromTree(aContext);
    132 
    133  (void)UpdateStyleSheetInternal(oldDoc, oldShadowRoot);
    134 }
    135 
    136 bool HTMLLinkElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
    137                                     const nsAString& aValue,
    138                                     nsIPrincipal* aMaybeScriptedPrincipal,
    139                                     nsAttrValue& aResult) {
    140  if (aNamespaceID == kNameSpaceID_None) {
    141    if (aAttribute == nsGkAtoms::crossorigin) {
    142      ParseCORSValue(aValue, aResult);
    143      return true;
    144    }
    145 
    146    if (aAttribute == nsGkAtoms::as) {
    147      net::ParseAsValue(aValue, aResult);
    148      return true;
    149    }
    150 
    151    if (aAttribute == nsGkAtoms::sizes) {
    152      aResult.ParseAtomArray(aValue);
    153      return true;
    154    }
    155 
    156    if (aAttribute == nsGkAtoms::integrity) {
    157      aResult.ParseStringOrAtom(aValue);
    158      return true;
    159    }
    160 
    161    if (aAttribute == nsGkAtoms::fetchpriority) {
    162      ParseFetchPriority(aValue, aResult);
    163      return true;
    164    }
    165 
    166    if (aAttribute == nsGkAtoms::blocking &&
    167        StaticPrefs::dom_element_blocking_enabled()) {
    168      aResult.ParseAtomArray(aValue);
    169      return true;
    170    }
    171  }
    172 
    173  return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
    174                                              aMaybeScriptedPrincipal, aResult);
    175 }
    176 
    177 void HTMLLinkElement::CreateAndDispatchEvent(const nsAString& aEventName) {
    178  MOZ_ASSERT(IsInUncomposedDoc());
    179 
    180  // In the unlikely case that both rev is specified *and* rel=stylesheet,
    181  // this code will cause the event to fire, on the principle that maybe the
    182  // page really does want to specify that its author is a stylesheet. Since
    183  // this should never actually happen and the performance hit is minimal,
    184  // doing the "right" thing costs virtually nothing here, even if it doesn't
    185  // make much sense.
    186  static AttrArray::AttrValuesArray strings[] = {
    187      nsGkAtoms::_empty, nsGkAtoms::stylesheet, nullptr};
    188 
    189  if (!nsContentUtils::HasNonEmptyAttr(this, kNameSpaceID_None,
    190                                       nsGkAtoms::rev) &&
    191      FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::rel, strings,
    192                      eIgnoreCase) != AttrArray::ATTR_VALUE_NO_MATCH) {
    193    return;
    194  }
    195 
    196  RefPtr<AsyncEventDispatcher> asyncDispatcher = new AsyncEventDispatcher(
    197      this, aEventName, CanBubble::eYes, ChromeOnlyDispatch::eYes);
    198  // Always run async in order to avoid running script when the content
    199  // sink isn't expecting it.
    200  asyncDispatcher->PostDOMEvent();
    201 }
    202 
    203 void HTMLLinkElement::BeforeSetAttr(int32_t aNameSpaceID, nsAtom* aName,
    204                                    const nsAttrValue* aValue, bool aNotify) {
    205  if (aNameSpaceID == kNameSpaceID_None &&
    206      (aName == nsGkAtoms::href || aName == nsGkAtoms::rel)) {
    207    CancelDNSPrefetch(*this);
    208    CancelPrefetchOrPreload();
    209  }
    210 
    211  return nsGenericHTMLElement::BeforeSetAttr(aNameSpaceID, aName, aValue,
    212                                             aNotify);
    213 }
    214 
    215 void HTMLLinkElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
    216                                   const nsAttrValue* aValue,
    217                                   const nsAttrValue* aOldValue,
    218                                   nsIPrincipal* aSubjectPrincipal,
    219                                   bool aNotify) {
    220  if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::href) {
    221    mCachedURI = nullptr;
    222    if (IsInUncomposedDoc()) {
    223      CreateAndDispatchEvent(u"DOMLinkChanged"_ns);
    224    }
    225    mTriggeringPrincipal = nsContentUtils::GetAttrTriggeringPrincipal(
    226        this, nsAttrValueOrString(aValue).String(), aSubjectPrincipal);
    227 
    228    // If the link has `rel=localization` and its `href` attribute is changed,
    229    // update the list of localization links.
    230    if (AttrValueIs(kNameSpaceID_None, nsGkAtoms::rel, nsGkAtoms::localization,
    231                    eIgnoreCase)) {
    232      if (Document* doc = GetUncomposedDoc()) {
    233        if (aOldValue) {
    234          doc->LocalizationLinkRemoved(this);
    235        }
    236        if (aValue) {
    237          doc->LocalizationLinkAdded(this);
    238        }
    239      }
    240    }
    241  }
    242 
    243  // If a link's `rel` attribute was changed from or to `localization`,
    244  // update the list of localization links.
    245  if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::rel) {
    246    if (Document* doc = GetUncomposedDoc()) {
    247      if ((aValue && aValue->Equals(nsGkAtoms::localization, eIgnoreCase)) &&
    248          (!aOldValue ||
    249           !aOldValue->Equals(nsGkAtoms::localization, eIgnoreCase))) {
    250        doc->LocalizationLinkAdded(this);
    251      } else if ((aOldValue &&
    252                  aOldValue->Equals(nsGkAtoms::localization, eIgnoreCase)) &&
    253                 (!aValue ||
    254                  !aValue->Equals(nsGkAtoms::localization, eIgnoreCase))) {
    255        doc->LocalizationLinkRemoved(this);
    256      }
    257    }
    258  }
    259 
    260  if (aValue) {
    261    if (aNameSpaceID == kNameSpaceID_None &&
    262        (aName == nsGkAtoms::href || aName == nsGkAtoms::rel ||
    263         aName == nsGkAtoms::title || aName == nsGkAtoms::media ||
    264         aName == nsGkAtoms::type || aName == nsGkAtoms::as ||
    265         aName == nsGkAtoms::crossorigin || aName == nsGkAtoms::disabled)) {
    266      bool dropSheet = false;
    267      if (aName == nsGkAtoms::rel) {
    268        nsAutoString value;
    269        aValue->ToString(value);
    270        uint32_t linkTypes = ParseLinkTypes(value);
    271        if (GetSheet()) {
    272          dropSheet = !(linkTypes & eSTYLESHEET);
    273        }
    274      }
    275 
    276      if ((aName == nsGkAtoms::rel || aName == nsGkAtoms::href) &&
    277          IsInComposedDoc()) {
    278        TryDNSPrefetchOrPreconnectOrPrefetchOrPreloadOrPrerender();
    279      }
    280 
    281      if ((aName == nsGkAtoms::as || aName == nsGkAtoms::type ||
    282           aName == nsGkAtoms::crossorigin || aName == nsGkAtoms::media) &&
    283          IsInComposedDoc()) {
    284        UpdatePreload(aName, aValue, aOldValue);
    285      }
    286 
    287      const bool forceUpdate =
    288          dropSheet || aName == nsGkAtoms::title || aName == nsGkAtoms::media ||
    289          aName == nsGkAtoms::type || aName == nsGkAtoms::disabled;
    290 
    291      (void)UpdateStyleSheetInternal(
    292          nullptr, nullptr, forceUpdate ? ForceUpdate::Yes : ForceUpdate::No);
    293    }
    294  } else {
    295    if (aNameSpaceID == kNameSpaceID_None) {
    296      if (aName == nsGkAtoms::disabled) {
    297        mExplicitlyEnabled = true;
    298      }
    299      // Since removing href or rel makes us no longer link to a stylesheet,
    300      // force updates for those too.
    301      if (aName == nsGkAtoms::href || aName == nsGkAtoms::rel ||
    302          aName == nsGkAtoms::title || aName == nsGkAtoms::media ||
    303          aName == nsGkAtoms::type || aName == nsGkAtoms::disabled) {
    304        (void)UpdateStyleSheetInternal(nullptr, nullptr, ForceUpdate::Yes);
    305      }
    306      if ((aName == nsGkAtoms::as || aName == nsGkAtoms::type ||
    307           aName == nsGkAtoms::crossorigin || aName == nsGkAtoms::media) &&
    308          IsInComposedDoc()) {
    309        UpdatePreload(aName, aValue, aOldValue);
    310      }
    311    }
    312  }
    313 
    314  return nsGenericHTMLElement::AfterSetAttr(
    315      aNameSpaceID, aName, aValue, aOldValue, aSubjectPrincipal, aNotify);
    316 }
    317 
    318 // Keep this and the arrays below in sync with ToLinkMask in LinkStyle.cpp.
    319 #define SUPPORTED_REL_VALUES_BASE                                           \
    320  "preload", "prefetch", "dns-prefetch", "stylesheet", "next", "alternate", \
    321      "preconnect", "icon", "search", nullptr
    322 
    323 static const DOMTokenListSupportedToken sSupportedRelValueCombinations[][13] = {
    324    {SUPPORTED_REL_VALUES_BASE},
    325    {"manifest", SUPPORTED_REL_VALUES_BASE},
    326    {"modulepreload", SUPPORTED_REL_VALUES_BASE},
    327    {"modulepreload", "manifest", SUPPORTED_REL_VALUES_BASE},
    328    {"compression-dictionary", SUPPORTED_REL_VALUES_BASE},
    329    {"compression-dictionary", "manifest", SUPPORTED_REL_VALUES_BASE},
    330    {"compression-dictionary", "modulepreload", SUPPORTED_REL_VALUES_BASE},
    331    {"compression-dictionary", "modulepreload", "manifest",
    332     SUPPORTED_REL_VALUES_BASE}};
    333 #undef SUPPORTED_REL_VALUES_BASE
    334 
    335 nsDOMTokenList* HTMLLinkElement::RelList() {
    336  if (!mRelList) {
    337    int index = (StaticPrefs::dom_manifest_enabled() ? 1 : 0) |
    338                (StaticPrefs::network_modulepreload() ? 2 : 0) |
    339                (StaticPrefs::network_http_dictionaries_enable() ? 4 : 0);
    340 
    341    mRelList = new nsDOMTokenList(this, nsGkAtoms::rel,
    342                                  sSupportedRelValueCombinations[index]);
    343  }
    344  return mRelList;
    345 }
    346 
    347 Maybe<LinkStyle::SheetInfo> HTMLLinkElement::GetStyleSheetInfo() {
    348  nsAutoString rel;
    349  GetAttr(nsGkAtoms::rel, rel);
    350  uint32_t linkTypes = ParseLinkTypes(rel);
    351  if (!(linkTypes & eSTYLESHEET)) {
    352    return Nothing();
    353  }
    354 
    355  if (!IsCSSMimeTypeAttributeForLinkElement(*this)) {
    356    return Nothing();
    357  }
    358 
    359  if (Disabled()) {
    360    return Nothing();
    361  }
    362 
    363  nsAutoString title;
    364  nsAutoString media;
    365  GetTitleAndMediaForElement(*this, title, media);
    366 
    367  bool alternate = linkTypes & eALTERNATE;
    368  if (alternate && title.IsEmpty()) {
    369    // alternates must have title.
    370    return Nothing();
    371  }
    372 
    373  if (!HasNonEmptyAttr(nsGkAtoms::href)) {
    374    return Nothing();
    375  }
    376 
    377  nsAutoString integrity;
    378  GetAttr(nsGkAtoms::integrity, integrity);
    379 
    380  nsCOMPtr<nsIURI> uri = GetURI();
    381  nsCOMPtr<nsIPrincipal> prin = mTriggeringPrincipal;
    382 
    383  nsAutoString nonce;
    384  nsString* cspNonce = static_cast<nsString*>(GetProperty(nsGkAtoms::nonce));
    385  if (cspNonce) {
    386    nonce = *cspNonce;
    387  }
    388 
    389  return Some(SheetInfo{
    390      *OwnerDoc(),
    391      this,
    392      uri.forget(),
    393      prin.forget(),
    394      MakeAndAddRef<ReferrerInfo>(*this),
    395      GetCORSMode(),
    396      title,
    397      media,
    398      integrity,
    399      nonce,
    400      alternate ? HasAlternateRel::Yes : HasAlternateRel::No,
    401      IsInline::No,
    402      mExplicitlyEnabled ? IsExplicitlyEnabled::Yes : IsExplicitlyEnabled::No,
    403      Element::GetFetchPriority(),
    404  });
    405 }
    406 
    407 void HTMLLinkElement::AddSizeOfExcludingThis(nsWindowSizes& aSizes,
    408                                             size_t* aNodeSize) const {
    409  nsGenericHTMLElement::AddSizeOfExcludingThis(aSizes, aNodeSize);
    410 
    411  // It is okay to include the size of mCachedURI here even though it might have
    412  // strong references from elsewhere because the URI was created for this
    413  // object, in nsGenericHTMLElement::GetURIAttr(). Only objects that created
    414  // their own URI will call nsIURI::SizeOfIncludingThis().
    415  if (mCachedURI) {
    416    *aNodeSize += mCachedURI->SizeOfIncludingThis(aSizes.mState.mMallocSizeOf);
    417  }
    418 }
    419 
    420 JSObject* HTMLLinkElement::WrapNode(JSContext* aCx,
    421                                    JS::Handle<JSObject*> aGivenProto) {
    422  return HTMLLinkElement_Binding::Wrap(aCx, this, aGivenProto);
    423 }
    424 
    425 void HTMLLinkElement::GetAs(nsAString& aResult) {
    426  GetEnumAttr(nsGkAtoms::as, "", aResult);
    427 }
    428 
    429 void HTMLLinkElement::GetContentPolicyMimeTypeMedia(
    430    nsAttrValue& aAsAttr, nsContentPolicyType& aPolicyType, nsString& aMimeType,
    431    nsAString& aMedia) {
    432  nsAutoString as;
    433  GetAttr(nsGkAtoms::as, as);
    434  net::ParseAsValue(as, aAsAttr);
    435  aPolicyType = net::AsValueToContentPolicy(aAsAttr);
    436 
    437  nsAutoString type;
    438  GetAttr(nsGkAtoms::type, type);
    439  nsAutoString notUsed;
    440  nsContentUtils::SplitMimeType(type, aMimeType, notUsed);
    441 
    442  GetAttr(nsGkAtoms::media, aMedia);
    443 }
    444 
    445 void HTMLLinkElement::
    446    TryDNSPrefetchOrPreconnectOrPrefetchOrPreloadOrPrerender() {
    447  MOZ_ASSERT(IsInComposedDoc());
    448  if (!HasAttr(nsGkAtoms::href)) {
    449    return;
    450  }
    451 
    452  nsAutoString rel;
    453  if (!GetAttr(nsGkAtoms::rel, rel)) {
    454    return;
    455  }
    456 
    457  if (!nsContentUtils::PrefetchPreloadEnabled(OwnerDoc()->GetDocShell())) {
    458    return;
    459  }
    460 
    461  uint32_t linkTypes = ParseLinkTypes(rel);
    462 
    463  if ((linkTypes & ePREFETCH) || (linkTypes & eNEXT)) {
    464    nsCOMPtr<nsIPrefetchService> prefetchService(
    465        components::Prefetch::Service());
    466    if (prefetchService) {
    467      if (nsCOMPtr<nsIURI> uri = GetURI()) {
    468        auto referrerInfo = MakeRefPtr<ReferrerInfo>(*this);
    469        prefetchService->PrefetchURI(uri, referrerInfo, this,
    470                                     linkTypes & ePREFETCH);
    471        return;
    472      }
    473    }
    474  }
    475 
    476  if (linkTypes & eCOMPRESSION_DICTIONARY) {
    477    if (nsCOMPtr<nsIURI> uri = GetURI()) {
    478      StartPreload(nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD);
    479      return;
    480    }
    481  }
    482 
    483  if (linkTypes & ePRELOAD) {
    484    if (nsCOMPtr<nsIURI> uri = GetURI()) {
    485      nsContentPolicyType policyType;
    486 
    487      nsAttrValue asAttr;
    488      nsAutoString mimeType;
    489      nsAutoString media;
    490      GetContentPolicyMimeTypeMedia(asAttr, policyType, mimeType, media);
    491 
    492      if (policyType == nsIContentPolicy::TYPE_INVALID ||
    493          !net::CheckPreloadAttrs(asAttr, mimeType, media, OwnerDoc())) {
    494        // Ignore preload with a wrong or empty as attribute.
    495        net::WarnIgnoredPreload(*OwnerDoc(), *uri);
    496        return;
    497      }
    498 
    499      // https://html.spec.whatwg.org/#translate-a-preload-destination
    500      // If destination is not "fetch", "font", "image", "script", "style", or
    501      // "track", then return null.
    502      int16_t asValue = asAttr.GetEnumValue();
    503      if (asValue != net::DESTINATION_FETCH &&
    504          asValue != net::DESTINATION_FONT &&
    505          asValue != net::DESTINATION_IMAGE &&
    506          asValue != net::DESTINATION_SCRIPT &&
    507          asValue != net::DESTINATION_STYLE &&
    508          asValue != net::DESTINATION_TRACK) {
    509        // TODO: Currently the spec doesn't define an event handler to be called
    510        // , but this is under discussion.
    511        // See: https://github.com/whatwg/html/issues/10940
    512        //
    513        // Post a "load" event here to match the legacy behavior.
    514        RefPtr<AsyncEventDispatcher> asyncDispatcher = new AsyncEventDispatcher(
    515            this, u"load"_ns, CanBubble::eNo, ChromeOnlyDispatch::eNo);
    516        asyncDispatcher->PostDOMEvent();
    517        return;
    518      }
    519 
    520      StartPreload(policyType);
    521      return;
    522    }
    523  }
    524 
    525  if (linkTypes & eMODULE_PRELOAD) {
    526    ScriptLoader* scriptLoader = OwnerDoc()->GetScriptLoader();
    527    if (!scriptLoader) {
    528      return;
    529    }
    530    ModuleLoader* moduleLoader = scriptLoader->GetModuleLoader();
    531 
    532    if (!moduleLoader) {
    533      // For the print preview documents, at this moment it doesn't have module
    534      // loader yet, as the (print preview) document is not attached to the
    535      // nsIDocumentViewer yet, so it doesn't have the GlobalObject.
    536      // Also, the script elements won't be processed as they are also cloned
    537      // from the original document.
    538      // So we simply bail out if the module loader is null.
    539      return;
    540    }
    541 
    542    if (!StaticPrefs::network_modulepreload()) {
    543      // Keep behavior from https://phabricator.services.mozilla.com/D149371,
    544      // prior to main implementation of modulepreload
    545      moduleLoader->DisallowImportMaps();
    546      return;
    547    }
    548 
    549    // https://html.spec.whatwg.org/multipage/semantics.html#processing-the-media-attribute
    550    // TODO: apply this check for all linkTypes
    551    nsAutoString media;
    552    if (GetAttr(nsGkAtoms::media, media)) {
    553      RefPtr<mozilla::dom::MediaList> mediaList =
    554          mozilla::dom::MediaList::Create(NS_ConvertUTF16toUTF8(media));
    555      if (!mediaList->Matches(*OwnerDoc())) {
    556        return;
    557      }
    558    }
    559 
    560    // TODO: per spec, apply this check for ePREFETCH as well
    561    if (!HasNonEmptyAttr(nsGkAtoms::href)) {
    562      return;
    563    }
    564 
    565    nsAutoString as;
    566    GetAttr(nsGkAtoms::as, as);
    567 
    568    if (!net::IsScriptLikeOrInvalid(as)) {
    569      RefPtr<AsyncEventDispatcher> asyncDispatcher = new AsyncEventDispatcher(
    570          this, u"error"_ns, CanBubble::eNo, ChromeOnlyDispatch::eNo);
    571      asyncDispatcher->PostDOMEvent();
    572      return;
    573    }
    574 
    575    nsCOMPtr<nsIURI> uri = GetURI();
    576    if (!uri) {
    577      return;
    578    }
    579 
    580    // https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-modulepreload-module-script-graph
    581    // Step 1. Disallow further import maps given settings object.
    582    moduleLoader->DisallowImportMaps();
    583 
    584    StartPreload(nsIContentPolicy::TYPE_SCRIPT);
    585    return;
    586  }
    587 
    588  if (linkTypes & ePRECONNECT) {
    589    if (nsCOMPtr<nsIURI> uri = GetURI()) {
    590      OwnerDoc()->MaybePreconnect(
    591          uri, AttrValueToCORSMode(GetParsedAttr(nsGkAtoms::crossorigin)));
    592      return;
    593    }
    594  }
    595 
    596  if (linkTypes & eDNS_PREFETCH) {
    597    TryDNSPrefetch(*this, HTMLDNSPrefetch::PrefetchSource::LinkDnsPrefetch);
    598  }
    599 }
    600 
    601 void HTMLLinkElement::UpdatePreload(nsAtom* aName, const nsAttrValue* aValue,
    602                                    const nsAttrValue* aOldValue) {
    603  MOZ_ASSERT(IsInComposedDoc());
    604 
    605  if (!HasAttr(nsGkAtoms::href)) {
    606    return;
    607  }
    608 
    609  nsAutoString rel;
    610  if (!GetAttr(nsGkAtoms::rel, rel)) {
    611    return;
    612  }
    613 
    614  if (!nsContentUtils::PrefetchPreloadEnabled(OwnerDoc()->GetDocShell())) {
    615    return;
    616  }
    617 
    618  uint32_t linkTypes = ParseLinkTypes(rel);
    619 
    620  if (!(linkTypes & ePRELOAD)) {
    621    return;
    622  }
    623 
    624  nsCOMPtr<nsIURI> uri = GetURI();
    625  if (!uri) {
    626    return;
    627  }
    628 
    629  nsAttrValue asAttr;
    630  nsContentPolicyType asPolicyType;
    631  nsAutoString mimeType;
    632  nsAutoString media;
    633  GetContentPolicyMimeTypeMedia(asAttr, asPolicyType, mimeType, media);
    634 
    635  if (asPolicyType == nsIContentPolicy::TYPE_INVALID ||
    636      !net::CheckPreloadAttrs(asAttr, mimeType, media, OwnerDoc())) {
    637    // Ignore preload with a wrong or empty as attribute, but be sure to cancel
    638    // the old one.
    639    CancelPrefetchOrPreload();
    640    net::WarnIgnoredPreload(*OwnerDoc(), *uri);
    641    return;
    642  }
    643 
    644  if (aName == nsGkAtoms::crossorigin) {
    645    CORSMode corsMode = AttrValueToCORSMode(aValue);
    646    CORSMode oldCorsMode = AttrValueToCORSMode(aOldValue);
    647    if (corsMode != oldCorsMode) {
    648      CancelPrefetchOrPreload();
    649      StartPreload(asPolicyType);
    650    }
    651    return;
    652  }
    653 
    654  nsContentPolicyType oldPolicyType;
    655 
    656  if (aName == nsGkAtoms::as) {
    657    if (aOldValue) {
    658      oldPolicyType = net::AsValueToContentPolicy(*aOldValue);
    659      if (!net::CheckPreloadAttrs(*aOldValue, mimeType, media, OwnerDoc())) {
    660        oldPolicyType = nsIContentPolicy::TYPE_INVALID;
    661      }
    662    } else {
    663      oldPolicyType = nsIContentPolicy::TYPE_INVALID;
    664    }
    665  } else if (aName == nsGkAtoms::type) {
    666    nsAutoString oldType;
    667    nsAutoString notUsed;
    668    if (aOldValue) {
    669      aOldValue->ToString(oldType);
    670    }
    671    nsAutoString oldMimeType;
    672    nsContentUtils::SplitMimeType(oldType, oldMimeType, notUsed);
    673    if (net::CheckPreloadAttrs(asAttr, oldMimeType, media, OwnerDoc())) {
    674      oldPolicyType = asPolicyType;
    675    } else {
    676      oldPolicyType = nsIContentPolicy::TYPE_INVALID;
    677    }
    678  } else {
    679    MOZ_ASSERT(aName == nsGkAtoms::media);
    680    nsAutoString oldMedia;
    681    if (aOldValue) {
    682      aOldValue->ToString(oldMedia);
    683    }
    684    if (net::CheckPreloadAttrs(asAttr, mimeType, oldMedia, OwnerDoc())) {
    685      oldPolicyType = asPolicyType;
    686    } else {
    687      oldPolicyType = nsIContentPolicy::TYPE_INVALID;
    688    }
    689  }
    690 
    691  if (asPolicyType != oldPolicyType &&
    692      oldPolicyType != nsIContentPolicy::TYPE_INVALID) {
    693    CancelPrefetchOrPreload();
    694  }
    695 
    696  // Trigger a new preload if the policy type has changed.
    697  if (asPolicyType != oldPolicyType) {
    698    StartPreload(asPolicyType);
    699  }
    700 }
    701 
    702 void HTMLLinkElement::CancelPrefetchOrPreload() {
    703  CancelPreload();
    704 
    705  nsCOMPtr<nsIPrefetchService> prefetchService(components::Prefetch::Service());
    706  if (prefetchService) {
    707    if (nsCOMPtr<nsIURI> uri = GetURI()) {
    708      prefetchService->CancelPrefetchPreloadURI(uri, this);
    709    }
    710  }
    711 }
    712 
    713 void HTMLLinkElement::StartPreload(nsContentPolicyType aPolicyType) {
    714  MOZ_ASSERT(!mPreload, "Forgot to cancel the running preload");
    715  RefPtr<PreloaderBase> preload =
    716      OwnerDoc()->Preloads().PreloadLinkElement(this, aPolicyType);
    717  mPreload = preload.get();
    718 }
    719 
    720 void HTMLLinkElement::CancelPreload() {
    721  if (mPreload) {
    722    // This will cancel the loading channel if this was the last referred node
    723    // and the preload is not used up until now to satisfy a regular tag load
    724    // request.
    725    mPreload->RemoveLinkPreloadNode(this);
    726    mPreload = nullptr;
    727  }
    728 }
    729 
    730 bool HTMLLinkElement::IsCSSMimeTypeAttributeForLinkElement(
    731    const Element& aSelf) {
    732  // Processing the type attribute per
    733  // https://html.spec.whatwg.org/multipage/semantics.html#processing-the-type-attribute
    734  // for HTML link elements.
    735  nsAutoString type;
    736  nsAutoString mimeType;
    737  nsAutoString notUsed;
    738  aSelf.GetAttr(nsGkAtoms::type, type);
    739  nsContentUtils::SplitMimeType(type, mimeType, notUsed);
    740  return mimeType.IsEmpty() || mimeType.LowerCaseEqualsLiteral("text/css");
    741 }
    742 
    743 nsDOMTokenList* HTMLLinkElement::Blocking() {
    744  if (!mBlocking) {
    745    mBlocking =
    746        new nsDOMTokenList(this, nsGkAtoms::blocking, sSupportedBlockingValues);
    747  }
    748  return mBlocking;
    749 }
    750 
    751 bool HTMLLinkElement::IsPotentiallyRenderBlocking() {
    752  return BlockingContainsRender();
    753 
    754  // TODO: handle implicitly potentially render blocking
    755  // https://html.spec.whatwg.org/#implicitly-potentially-render-blocking
    756  // The default type for resources given by the stylesheet keyword is text/css.
    757  // A link element of this type is implicitly potentially render-blocking if
    758  // the element was created by its node document's parser.
    759 }
    760 
    761 nsresult HTMLLinkElement::CopyInnerTo(HTMLLinkElement* aDest) {
    762  nsresult rv = Element::CopyInnerTo(aDest);
    763  NS_ENSURE_SUCCESS(rv, rv);
    764  MaybeStartCopyStyleSheetTo(aDest, aDest->OwnerDoc());
    765  return NS_OK;
    766 }
    767 
    768 }  // namespace mozilla::dom
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