[WIP Prototype] ES6 https://html.spec.whatwg.org/#fetch-a-single-module-script implementation

third_party/WebKit/Source/core/dom/ScriptLoader.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/dom/ScriptLoader.h"
 
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/ScriptSourceCode.h"
+#include "bindings/core/v8/ScriptState.h"
 #include "core/HTMLNames.h"
 #include "core/SVGNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/DocumentParserTiming.h"
 #include "core/dom/IgnoreDestructiveWriteCountIncrementer.h"
+#include "core/dom/Modulator.h"
+#include "core/dom/ModuleScript.h"
 #include "core/dom/ScriptLoaderClient.h"
 #include "core/dom/ScriptRunner.h"
 #include "core/dom/ScriptableDocumentParser.h"
 #include "core/dom/Text.h"
 #include "core/events/Event.h"
 #include "core/fetch/AccessControlStatus.h"
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/MemoryCache.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/SubresourceIntegrity.h"
 #include "core/frame/UseCounter.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/CrossOriginAttribute.h"
 #include "core/html/HTMLScriptElement.h"
 #include "core/html/imports/HTMLImport.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/svg/SVGScriptElement.h"
 #include "platform/WebFrameScheduler.h"
 #include "platform/network/mime/MIMETypeRegistry.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "public/platform/WebCachePolicy.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/text/StringBuilder.h"
 #include "wtf/text/StringHash.h"
 
 namespace blink {
 
+class ScriptElementModuleClient
+    : public GarbageCollectedFinalized<ScriptElementModuleClient>,
+      public ModuleTreeClient {
+  USING_GARBAGE_COLLECTED_MIXIN(ScriptElementModuleClient);
+
+ public:
+  static ScriptElementModuleClient* create(Element* element) {
+    return new ScriptElementModuleClient(element);
+  }
+  virtual ~ScriptElementModuleClient() = default;
+
+  DECLARE_TRACE();
+
+ private:
+  ScriptElementModuleClient(Element* element) : m_element(element) {}
+
+  // Implements ModuleTreeClient
+  void notifyFinishedModuleTree(ModuleScript*) override;
+
+  Member<Element> m_element;
+};
+
+void ScriptElementModuleClient::notifyFinishedModuleTree(
+    ModuleScript* moduleScript) {
+  printf("notifyFinishedModuleTree!!! moduleScript: %p\n", moduleScript);
+  if (!moduleScript)
+    return;
+  DCHECK(moduleScript->instantiationState() ==
+         InstantiationState::Instantiated);
+
+  LocalFrame* frame = m_element->document().frame();
+
+  // TODO(kouhei): Actually we should just return w/ the prepared script here.
+  // In this prototype, we will execute the module immediately just for fun. :)
+  Modulator::from(frame)->executeModule(moduleScript->record());
+}
+
+DEFINE_TRACE(ScriptElementModuleClient) {
+  visitor->trace(m_element);
+  ModuleTreeClient::trace(visitor);
+}
+
 ScriptLoader::ScriptLoader(Element* element,
                            bool parserInserted,
                            bool alreadyStarted,
                            bool createdDuringDocumentWrite)
     : m_element(element),
       m_startLineNumber(WTF::OrdinalNumber::beforeFirst()),
       m_parserInserted(parserInserted),
       m_isExternalScript(false),
       m_alreadyStarted(alreadyStarted),
       m_haveFiredLoad(false),
@@ skipping 10 matching lines @@
       !element->document().isInDocumentWrite())
     m_startLineNumber =
         element->document().scriptableDocumentParser()->lineNumber();
 }
 
 ScriptLoader::~ScriptLoader() {}
 
 DEFINE_TRACE(ScriptLoader) {
   visitor->trace(m_element);
   visitor->trace(m_resource);
+  visitor->trace(m_elementModuleClient);
   visitor->trace(m_pendingScript);
   PendingScriptClient::trace(visitor);
 }
 
 void ScriptLoader::setFetchDocWrittenScriptDeferIdle() {
   DCHECK(!m_createdDuringDocumentWrite);
   m_documentWriteIntervention =
       DocumentWriteIntervention::FetchDocWrittenScriptDeferIdle;
 }
 
@@ skipping 150 matching lines @@
     m_characterEncoding = elementDocument.characterSet();
 
   if (client->hasSourceAttribute()) {
     FetchRequest::DeferOption defer = FetchRequest::NoDefer;
     if (!m_parserInserted || client->asyncAttributeValue() ||
         client->deferAttributeValue())
       defer = FetchRequest::LazyLoad;
     if (m_documentWriteIntervention ==
         DocumentWriteIntervention::FetchDocWrittenScriptDeferIdle)
       defer = FetchRequest::IdleLoad;
+
     if (!fetchScript(client->sourceAttributeValue(), defer))
       return false;
   }
 
   // Since the asynchronous, low priority fetch for doc.written blocked
   // script is not for execution, return early from here. Watch for its
   // completion to be able to remove it from the memory cache.
   if (m_documentWriteIntervention ==
       DocumentWriteIntervention::FetchDocWrittenScriptDeferIdle) {
     m_pendingScript = PendingScript::create(m_element, m_resource.get());
@@ skipping 55 matching lines @@
 
 bool ScriptLoader::fetchScript(const String& sourceUrl,
                                FetchRequest::DeferOption defer) {
   DCHECK(m_element);
 
   Document* elementDocument = &(m_element->document());
   if (!m_element->isConnected() || m_element->document() != elementDocument)
     return false;
 
   DCHECK(!m_resource);
+
   if (!stripLeadingAndTrailingHTMLSpaces(sourceUrl).isEmpty()) {
-    FetchRequest request(
-        ResourceRequest(elementDocument->completeURL(sourceUrl)),
-        m_element->localName());
+    KURL url = elementDocument->completeURL(sourceUrl);
+    if (RuntimeEnabledFeatures::moduleScriptsEnabled() &&
+        client()->typeAttributeValue() == "module") {
+      m_elementModuleClient = ScriptElementModuleClient::create(m_element);
+
+      // TODO(kouhei): Per spec, we should actually pass in "settings object"
+      // which contains the baseURL.
+      KURL baseURL = elementDocument->baseURL();
+
+      Document* elementDocument = &(m_element->document());
+      Modulator::from(elementDocument->frame())

[dominicc (has gone to gerrit), 2017/01/11 03:23:48]

Feel like all these places need guards against shutdown, WDYT?

[kouhei (in TOK), 2017/01/17 05:26:13]

Is Line 381 isConnected check enough? Would you help me find which condition to
check?

+          ->fetchTree(url, baseURL, m_elementModuleClient);
+      return true;
+    }
+
+    FetchRequest request(ResourceRequest(url), m_element->localName());
 
     CrossOriginAttributeValue crossOrigin = crossOriginAttributeValue(
         m_element->fastGetAttribute(HTMLNames::crossoriginAttr));
     if (crossOrigin != CrossOriginAttributeNotSet)
       request.setCrossOriginAccessControl(elementDocument->getSecurityOrigin(),
                                           crossOrigin);
     request.setCharset(scriptCharset());
 
     if (ContentSecurityPolicy::isNonceableElement(m_element.get())) {
       request.setContentSecurityPolicyNonce(
@@ skipping 295 matching lines @@
   if (isHTMLScriptLoader(element))
     return toHTMLScriptElement(element)->loader();
 
   if (isSVGScriptLoader(element))
     return toSVGScriptElement(element)->loader();
 
   return 0;
 }
 
 }  // namespace blink