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

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

Index: third_party/WebKit/Source/core/dom/ScriptLoader.cpp
diff --git a/third_party/WebKit/Source/core/dom/ScriptLoader.cpp b/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
index 7b3915aaac0eec2ae7e42d89ecbea6a1915a3734..38e1429f6938a901f19c101d1a1211a711e4307d 100644
--- a/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
+++ b/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
@@ -26,11 +26,14 @@
 
 #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"
@@ -60,6 +63,48 @@
 
 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,
@@ -90,6 +135,7 @@ ScriptLoader::~ScriptLoader() {}
 DEFINE_TRACE(ScriptLoader) {
   visitor->trace(m_element);
   visitor->trace(m_resource);
+  visitor->trace(m_elementModuleClient);
   visitor->trace(m_pendingScript);
   PendingScriptClient::trace(visitor);
 }
@@ -260,6 +306,7 @@ bool ScriptLoader::prepareScript(const TextPosition& scriptStartPosition,
     if (m_documentWriteIntervention ==
         DocumentWriteIntervention::FetchDocWrittenScriptDeferIdle)
       defer = FetchRequest::IdleLoad;
+
     if (!fetchScript(client->sourceAttributeValue(), defer))
       return false;
   }
@@ -335,10 +382,24 @@ bool ScriptLoader::fetchScript(const String& sourceUrl,
     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));