Commit aa8c1138 authored by Em Zhan's avatar Em Zhan
Browse files

Bug 1425310 - Implement modulepreload for link rel. r=yulia,smaug,jonco 

Does perform the optional step of fetching descendants and linking:
https://html.spec.whatwg.org/multipage/webappapis.html#fetching-scripts:fetch-the-descendants-of-and-link-a-module-script-2

Partially implements some new destinations ("as" attribute values) for
modulepreload only (not for preload or link attribute reflection)

Differential Revision: https://phabricator.services.mozilla.com/D172368
parent d81ad62b

dom/html/HTMLLinkElement.cpp

+66 −29
Original line number Diff line number Diff line
@@ -311,36 +311,30 @@ void HTMLLinkElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName, 
      aNameSpaceID, aName, aValue, aOldValue, aSubjectPrincipal, aNotify);

}



static const DOMTokenListSupportedToken sSupportedRelValues[] = {

    // Keep this and the one below in sync with ToLinkMask in

    // LinkStyle.cpp.

    // "preload" must come first because it can be disabled.

    "preload", "prefetch",      "dns-prefetch", "stylesheet",

    "next",    "alternate",     "preconnect",   "icon",

    "search",  "modulepreload", nullptr};



static const DOMTokenListSupportedToken sSupportedRelValuesWithManifest[] = {

    // Keep this in sync with ToLinkMask in LinkStyle.cpp.

    // "preload" and "manifest" must come first because they can be disabled.

    "preload",   "manifest",   "prefetch", "dns-prefetch", "stylesheet", "next",

    "alternate", "preconnect", "icon",     "search",       nullptr};

// Keep this and the arrays below in sync with ToLinkMask in LinkStyle.cpp.

#define SUPPORTED_REL_VALUES_BASE                                              \

  "prefetch", "dns-prefetch", "stylesheet", "next", "alternate", "preconnect", \

      "icon", "search", nullptr



static const DOMTokenListSupportedToken sSupportedRelValueCombinations[][12] = {

    {SUPPORTED_REL_VALUES_BASE},

    {"manifest", SUPPORTED_REL_VALUES_BASE},

    {"preload", SUPPORTED_REL_VALUES_BASE},

    {"preload", "manifest", SUPPORTED_REL_VALUES_BASE},

    {"modulepreload", SUPPORTED_REL_VALUES_BASE},

    {"modulepreload", "manifest", SUPPORTED_REL_VALUES_BASE},

    {"modulepreload", "preload", SUPPORTED_REL_VALUES_BASE},

    {"modulepreload", "preload", "manifest", SUPPORTED_REL_VALUES_BASE}};

#undef SUPPORTED_REL_VALUES_BASE



nsDOMTokenList* HTMLLinkElement::RelList() {

  if (!mRelList) {

    auto preload = StaticPrefs::network_preload();

    auto manifest = StaticPrefs::dom_manifest_enabled();

    if (manifest && preload) {

      mRelList = new nsDOMTokenList(this, nsGkAtoms::rel,

                                    sSupportedRelValuesWithManifest);

    } else if (manifest && !preload) {

    int index = (StaticPrefs::dom_manifest_enabled() ? 1 : 0) |

                (StaticPrefs::network_preload() ? 2 : 0) |

                (StaticPrefs::network_modulepreload() ? 4 : 0);



    mRelList = new nsDOMTokenList(this, nsGkAtoms::rel,

                                    &sSupportedRelValuesWithManifest[1]);

    } else if (!manifest && preload) {

      mRelList = new nsDOMTokenList(this, nsGkAtoms::rel, sSupportedRelValues);

    } else {  // both false...drop preload

      mRelList =

          new nsDOMTokenList(this, nsGkAtoms::rel, &sSupportedRelValues[1]);

    }

                                  sSupportedRelValueCombinations[index]);

  }

  return mRelList;

}
@@ -490,7 +484,10 @@ void HTMLLinkElement:: 
  }



  if (linkTypes & eMODULE_PRELOAD) {

    if (!OwnerDoc()->ScriptLoader()->GetModuleLoader()) {

    ScriptLoader* scriptLoader = OwnerDoc()->ScriptLoader();

    ModuleLoader* moduleLoader = scriptLoader->GetModuleLoader();



    if (!moduleLoader) {

      // For the print preview documents, at this moment it doesn't have module

      // loader yet, as the (print preview) document is not attached to the

      // nsIContentViewer yet, so it doesn't have the GlobalObject.
@@ -500,9 +497,49 @@ void HTMLLinkElement:: 
      return;

    }



    if (!StaticPrefs::network_modulepreload()) {

      // Keep behavior from https://phabricator.services.mozilla.com/D149371,

      // prior to main implementation of modulepreload

      moduleLoader->DisallowImportMaps();

      return;

    }



    // https://html.spec.whatwg.org/multipage/semantics.html#processing-the-media-attribute

    // TODO: apply this check for all linkTypes

    nsAutoString media;

    if (GetAttr(nsGkAtoms::media, media)) {

      RefPtr<mozilla::dom::MediaList> mediaList =

          mozilla::dom::MediaList::Create(NS_ConvertUTF16toUTF8(media));

      if (!mediaList->Matches(*OwnerDoc())) {

        return;

      }

    }



    // TODO: per spec, apply this check for ePREFETCH as well

    if (!HasNonEmptyAttr(nsGkAtoms::href)) {

      return;

    }



    nsAutoString as;

    GetAttr(nsGkAtoms::as, as);



    if (!net::IsScriptLikeOrInvalid(as)) {

      RefPtr<AsyncEventDispatcher> asyncDispatcher = new AsyncEventDispatcher(

          this, u"error"_ns, CanBubble::eNo, ChromeOnlyDispatch::eNo);

      asyncDispatcher->PostDOMEvent();

      return;

    }



    nsCOMPtr<nsIURI> uri = GetURI();

    if (!uri) {

      return;

    }



    // https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-modulepreload-module-script-graph

    // Step 1. Disallow further import maps given settings object.

    OwnerDoc()->ScriptLoader()->GetModuleLoader()->DisallowImportMaps();

    moduleLoader->DisallowImportMaps();



    StartPreload(nsIContentPolicy::TYPE_SCRIPT);

    return;

  }

dom/script/ScriptLoadContext.h

+4 −3
Original line number Diff line number Diff line
@@ -62,9 +62,10 @@ class Element; 
 *        the script does not need to be fetched first.

 *    * mIsXSLT

 *        Set if we are in an XSLT request.

 *    * TODO: mIsPreload (will be moved from ScriptFetchOptions)

 *    * mIsPreload

 *        Set for scripts that are preloaded in a

 *        <link rel="preload" as="script"> element.

 *        <link rel="preload" as="script"> or <link rel="modulepreload">

 *        element.

 *

 * In addition to describing how the ScriptLoadRequest will be loaded by the

 * DOM ScriptLoader, the ScriptLoadContext contains fields that facilitate
@@ -113,7 +114,7 @@ class ScriptLoadContext : public JS::loader::LoadContextBase, 
    eDeferred,

    eAsync,

    eLinkPreload  // this is a load initiated by <link rel="preload"

                  // as="script"> tag

                  // as="script"> or <link rel="modulepreload"> tag

  };



  void SetScriptMode(bool aDeferAttr, bool aAsyncAttr, bool aLinkPreload);

dom/script/ScriptLoader.cpp

+8 −7
Original line number Diff line number Diff line
@@ -675,12 +675,12 @@ nsresult ScriptLoader::StartLoadInternal( 
       aRequest->GetScriptLoadContext()->IsTracking()));



  if (aRequest->GetScriptLoadContext()->IsLinkPreloadScript()) {

    // This is <link rel="preload" as="script"> initiated speculative load,

    // put it to the group that is not blocked by leaders and doesn't block

    // follower at the same time. Giving it a much higher priority will make

    // this request be processed ahead of other Unblocked requests, but with

    // the same weight as Leaders.  This will make us behave similar way for

    // both http2 and http1.

    // This is <link rel="preload" as="script"> or <link rel="modulepreload">

    // initiated speculative load, put it to the group that is not blocked by

    // leaders and doesn't block follower at the same time. Giving it a much

    // higher priority will make this request be processed ahead of other

    // Unblocked requests, but with the same weight as Leaders. This will make

    // us behave similar way for both http2 and http1.

    ScriptLoadContext::PrioritizeAsPreload(channel);

    ScriptLoadContext::AddLoadBackgroundFlag(channel);

  } else if (nsCOMPtr<nsIClassOfService> cos = do_QueryInterface(channel)) {
@@ -786,7 +786,8 @@ nsresult ScriptLoader::StartLoadInternal( 
      aRequest->mURI, aRequest->CORSMode(), aRequest->mKind);

  aRequest->GetScriptLoadContext()->NotifyOpen(

      key, channel, mDocument,

      aRequest->GetScriptLoadContext()->IsLinkPreloadScript());

      aRequest->GetScriptLoadContext()->IsLinkPreloadScript(),

      aRequest->IsModuleRequest());



  if (aEarlyHintPreloaderId) {

    nsCOMPtr<nsIHttpChannelInternal> channelInternal =

modules/libpref/init/StaticPrefList.yaml

+10 −1
Original line number Diff line number Diff line
@@ -11673,12 +11673,21 @@ 
  value: false

  mirror: always



# Enables `<link rel="preload">` tag and `Link: rel=preload` response header handling.

# Enables `<link rel="preload">` tag and `Link: rel=preload` response header

# handling.

- name: network.preload

  type: RelaxedAtomicBool

  value: true

  mirror: always



# Enables `<link rel="modulepreload">` tag and `Link: rel=modulepreload`

# response header handling. The latter is not yet implemented, see:

# https://bugzilla.mozilla.org/show_bug.cgi?id=1773056.

- name: network.modulepreload

  type: RelaxedAtomicBool

  value: true

  mirror: always



# Enable 103 Early Hint status code (RFC 8297)

- name: network.early-hints.enabled

  type: RelaxedAtomicBool

netwerk/base/nsNetUtil.cpp

+18 −0
Original line number Diff line number Diff line
@@ -3756,6 +3756,24 @@ nsContentPolicyType AsValueToContentPolicy(const nsAttrValue& aValue) { 
  return nsIContentPolicy::TYPE_INVALID;

}



// TODO: implement this using nsAttrValue's destination enums when support for

// the new destinations is added; see this diff for a possible start:

// https://phabricator.services.mozilla.com/D172368?vs=705114&id=708720

bool IsScriptLikeOrInvalid(const nsAString& aAs) {

  return !(

      aAs.LowerCaseEqualsASCII("fetch") || aAs.LowerCaseEqualsASCII("audio") ||

      aAs.LowerCaseEqualsASCII("document") ||

      aAs.LowerCaseEqualsASCII("embed") || aAs.LowerCaseEqualsASCII("font") ||

      aAs.LowerCaseEqualsASCII("frame") || aAs.LowerCaseEqualsASCII("iframe") ||

      aAs.LowerCaseEqualsASCII("image") ||

      aAs.LowerCaseEqualsASCII("manifest") ||

      aAs.LowerCaseEqualsASCII("object") ||

      aAs.LowerCaseEqualsASCII("report") || aAs.LowerCaseEqualsASCII("style") ||

      aAs.LowerCaseEqualsASCII("track") || aAs.LowerCaseEqualsASCII("video") ||

      aAs.LowerCaseEqualsASCII("webidentity") ||

      aAs.LowerCaseEqualsASCII("xslt"));

}



bool CheckPreloadAttrs(const nsAttrValue& aAs, const nsAString& aType,

                       const nsAString& aMedia,

                       mozilla::dom::Document* aDocument) {