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
iaxat · May 8, 2023 · 3fec06e · 3fec06e
1 parent 55eb6bc
commit 3fec06e
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Showing 18 changed files with 351 additions and 107 deletions.
diff --git a/dom/html/HTMLLinkElement.cpp b/dom/html/HTMLLinkElement.cpp
@@ -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) {
-      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]);
-    }
+    int index = (StaticPrefs::dom_manifest_enabled() ? 1 : 0) |
+                (StaticPrefs::network_preload() ? 2 : 0) |
+                (StaticPrefs::network_modulepreload() ? 4 : 0);
+
+    mRelList = new nsDOMTokenList(this, nsGkAtoms::rel,
+                                  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;
   }
 

diff --git a/dom/script/ScriptLoadContext.h b/dom/script/ScriptLoadContext.h
@@ -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);

diff --git a/dom/script/ScriptLoader.cpp b/dom/script/ScriptLoader.cpp
@@ -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 =

diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
@@ -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

diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
@@ -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) {

diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
@@ -1039,6 +1039,7 @@ enum ASDestination : uint8_t {
 
 void ParseAsValue(const nsAString& aValue, nsAttrValue& aResult);
 nsContentPolicyType AsValueToContentPolicy(const nsAttrValue& aValue);
+bool IsScriptLikeOrInvalid(const nsAString& aAs);
 
 bool CheckPreloadAttrs(const nsAttrValue& aAs, const nsAString& aType,
                        const nsAString& aMedia,

diff --git a/parser/html/nsHtml5SpeculativeLoad.h b/parser/html/nsHtml5SpeculativeLoad.h
@@ -334,8 +334,8 @@ class nsHtml5SpeculativeLoad {
 
   /**
    * True if and only if this is a speculative load initiated by <link
-   * rel="preload"> tag encounter.  Passed to the handling loader as an
-   * indication to raise the priority.
+   * rel="preload"> or <link rel="modulepreload"> tag encounter.  Passed to the
+   * handling loader as an indication to raise the priority.
    */
   bool mIsLinkPreload;
 
@@ -387,8 +387,8 @@ class nsHtml5SpeculativeLoad {
    * value of the "sizes" attribute. If the attribute is not set, this will
    * be a void string. If mOpCode is eSpeculativeLoadStyle, this
    * is the value of the "integrity" attribute. If the attribute is not set,
-   * this will be a void string. Otherwise it is empty or the value of the
-   * referrer policy. Otherwise, it is empty or the value of the type attribute.
+   * this will be a void string. Otherwise, it is empty or the value of the type
+   * attribute.
    */
   nsString mTypeOrCharsetSourceOrDocumentModeOrMetaCSPOrSizesOrIntegrity;
   /**

diff --git a/parser/html/nsHtml5TreeBuilderCppSupplement.h b/parser/html/nsHtml5TreeBuilderCppSupplement.h
@@ -336,6 +336,35 @@ nsIContentHandle* nsHtml5TreeBuilder::createElement(
                 }
                 // Other "as" values will be supported later.
               }
+            } else if (mozilla::StaticPrefs::network_modulepreload() &&
+                       rel.LowerCaseEqualsASCII("modulepreload")) {
+              nsHtml5String url =
+                  aAttributes->getValue(nsHtml5AttributeName::ATTR_HREF);
+              if (url && url.Length() != 0) {
+                nsHtml5String as =
+                    aAttributes->getValue(nsHtml5AttributeName::ATTR_AS);
+                nsAutoString asString;
+                as.ToString(asString);
+                if (net::IsScriptLikeOrInvalid(asString)) {
+                  nsHtml5String charset =
+                      aAttributes->getValue(nsHtml5AttributeName::ATTR_CHARSET);
+                  RefPtr<nsAtom> moduleType = nsGkAtoms::_module;
+                  nsHtml5String type =
+                      nsHtml5String::FromAtom(moduleType.forget());
+                  nsHtml5String crossOrigin = aAttributes->getValue(
+                      nsHtml5AttributeName::ATTR_CROSSORIGIN);
+                  nsHtml5String media =
+                      aAttributes->getValue(nsHtml5AttributeName::ATTR_MEDIA);
+                  nsHtml5String integrity = aAttributes->getValue(
+                      nsHtml5AttributeName::ATTR_INTEGRITY);
+                  nsHtml5String referrerPolicy = aAttributes->getValue(
+                      nsHtml5AttributeName::ATTR_REFERRERPOLICY);
+                  mSpeculativeLoadQueue.AppendElement()->InitScript(
+                      url, charset, type, crossOrigin, media, integrity,
+                      referrerPolicy, mode == nsHtml5TreeBuilder::IN_HEAD,
+                      false, false, false, true);
+                }
+              }
             }
           }
         } else if (nsGkAtoms::video == aName) {

diff --git a/testing/web-platform/meta/preload/avoid-delaying-onload-link-modulepreload-exec.html.ini b/testing/web-platform/meta/preload/avoid-delaying-onload-link-modulepreload-exec.html.ini
diff --git a/testing/web-platform/meta/preload/avoid-delaying-onload-link-modulepreload.html.ini b/testing/web-platform/meta/preload/avoid-delaying-onload-link-modulepreload.html.ini
diff --git a/testing/web-platform/meta/preload/modulepreload.html.ini b/testing/web-platform/meta/preload/modulepreload.html.ini