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

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

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/dom/ScriptModuleResolverImpl.h"
+
+#include "bindings/core/v8/ScriptModule.h"
+#include "core/dom/Modulator.h"
+#include "core/dom/ModuleScript.h"
+
+namespace blink {
+
+void ScriptModuleResolverImpl::registerModuleScript(
+    ModuleScript* moduleScript) {
+#ifndef NDEBUG
+  printf(
+      "ScriptModuleResolverImpl::registerModuleScript(url=\"%s\", hash=%u)\n",
+      moduleScript->baseURL().getString().utf8().data(),
+      ScriptModuleIdentifierHash::hash(moduleScript->record().identifier()));
+#endif
+
+  DCHECK(moduleScript);
+  DCHECK(!moduleScript->record().isNull());
+  auto result = m_recordToModuleScriptMap.set(
+      moduleScript->record().identifier(), moduleScript);
+  DCHECK(result.isNewEntry);
+}
+
+ScriptModule ScriptModuleResolverImpl::resolve(const String& specifier,
+                                               ScriptModuleIdentifier referrer,
+                                               ExceptionState& exceptionState) {
+// TODO(kouhei):
+// https://html.spec.whatwg.org/#hostresolveimportedmodule(referencingmodule,-specifier)
+#ifndef NDEBUG
+  printf("ScriptModuleResolverImpl::resolve(\"%s\") hash: %u\n",
+         specifier.utf8().data(), ScriptModuleIdentifierHash::hash(referrer));
+#endif
+
+  const auto it = m_recordToModuleScriptMap.find(referrer);
+  CHECK_NE(it, m_recordToModuleScriptMap.end())
+      << "Failed to find referrer ModuleScript corresponding to the record";
+  ModuleScript* referrerModule = it->value;
+
+  KURL url =
+      Modulator::resolveModuleSpecifier(specifier, referrerModule->baseURL());
+  ModuleScript* moduleScript = m_modulator->retrieveFetchedModuleScript(url);
+  return moduleScript->record();
+}
+
+DEFINE_TRACE(ScriptModuleResolverImpl) {
+  ScriptModuleResolver::trace(visitor);
+  visitor->trace(m_recordToModuleScriptMap);
+  visitor->trace(m_modulator);
+}
+
+}  // namespace blink