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

third_party/WebKit/Source/core/dom/ModulatorImpl.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/ModulatorImpl.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/ExecutionContext.h"
+#include "core/dom/ModuleMap.h"
+#include "core/dom/ModuleScript.h"
+#include "core/dom/ScriptModuleResolverImpl.h"
+#include "core/dom/TaskRunnerHelper.h"
+#include "core/frame/LocalFrame.h"
+#include "core/loader/modulescript//ModuleScriptFetchRequest.h"
+#include "core/loader/modulescript/ModuleScriptLoaderRegistry.h"
+#include "core/loader/modulescript/ModuleTreeLinkerRegistry.h"
+#include "platform/loader/fetch/ResourceFetcher.h"
+
+namespace blink {
+
+ModulatorImpl* ModulatorImpl::create(RefPtr<ScriptState> scriptState,
+                                     Document& document) {
+  return new ModulatorImpl(
+      std::move(scriptState),
+      TaskRunnerHelper::get(TaskType::Networking, &document), &document,
+      document.fetcher());
+}
+
+ModulatorImpl::ModulatorImpl(RefPtr<ScriptState> scriptState,
+                             RefPtr<WebTaskRunner> taskRunner,
+                             ExecutionContext* executionContext,
+                             ResourceFetcher* fetcher)
+    : m_scriptState(std::move(scriptState)),
+      m_taskRunner(std::move(taskRunner)),
+      m_executionContext(executionContext),
+      m_fetcher(fetcher),
+      m_map(ModuleMap::create(this)),
+      m_loaderRegistry(ModuleScriptLoaderRegistry::create()),
+      m_treeLinkerRegistry(ModuleTreeLinkerRegistry::create()),
+      m_scriptModuleResolver(ScriptModuleResolverImpl::create(this)) {
+  DCHECK(m_scriptState);
+  DCHECK(m_taskRunner);
+  DCHECK(m_executionContext);
+  DCHECK(m_fetcher);
+}
+
+ModulatorImpl::~ModulatorImpl() {}
+
+ReferrerPolicy ModulatorImpl::referrerPolicy() {
+  return m_executionContext->getReferrerPolicy();
+}
+
+void ModulatorImpl::fetchTree(const ModuleScriptFetchRequest& request,
+                              ModuleTreeClient* client) {
+  // Step 1. Perform the internal module script graph fetching procedure given
+  // url, settings object, destination, cryptographic nonce, parser state,
+  // credentials mode, settings object, a new empty list, "client", and with the
+  // top-level module fetch flag set. If the caller of this algorithm specified
+  // custom perform the fetch steps, pass those along as well.
+
+  // Note: "Fetch a module script graph" algorithm doesn't have "referrer" as
+  // its argument.
+  DCHECK(request.referrer().isNull());
+
+  AncestorList emptyAncestorList;
+  fetchTreeInternal(request, emptyAncestorList,
+                    ModuleGraphLevel::TopLevelModuleFetch, client);
+
+  // Step 2. When the internal module script graph fetching procedure
+  // asynchronously completes with result, asynchronously complete this
+  // algorithm with result.
+  // Note: We delegate to ModuleTreeLinker to notify ModuleTreeClient.
+}
+
+void ModulatorImpl::fetchTreeInternal(const ModuleScriptFetchRequest& request,
+                                      const AncestorList& ancestorList,
+                                      ModuleGraphLevel level,
+                                      ModuleTreeClient* client) {
+  m_treeLinkerRegistry->fetch(request, ancestorList, level, this, client);
+}
+
+void ModulatorImpl::fetchSingle(const ModuleScriptFetchRequest& request,
+                                ModuleGraphLevel level,
+                                SingleModuleClient* client) {
+  m_map->retrieveAndFetchIfNeeded(request, level, client);
+}
+
+void ModulatorImpl::fetchNewSingleModule(
+    const ModuleScriptFetchRequest& request,
+    ModuleGraphLevel level,
+    ModuleScriptLoaderClient* client) {
+  m_loaderRegistry->fetch(request, level, this, m_fetcher.get(), client);
+}
+
+ModuleScript* ModulatorImpl::retrieveFetchedModuleScript(const KURL& url) {
+  return m_map->retrieveFetchedModuleScript(url);
+}
+
+ScriptModule ModulatorImpl::compileModule(const String& script,
+                                          const String& urlStr) {
+  // Implements Steps 3-6 of
+  // https://html.spec.whatwg.org/multipage/webappapis.html#creating-a-module-script
+
+  // Step 3. Let realm be the provided environment settings object's Realm.
+  // Note: Realm is v8::Context.
+  // Step 4. If scripting is disabled for the given environment settings
+  // object's responsible browsing context, then let script source be the empty
+  // string. Otherwise, let script source be the provided script source.
+  // TODO(kouhei): if(m_executionContext->canExecuteScripts) after the CL
+  // landed.
+  // Step 5. Let result be ParseModule(script source, realm, script).
+  // Step 6. If result is a List of errors, report the exception given by the
+  // first element of result for script, return null, and abort these steps.
+  // Note: reporting is routed via V8Initializer::messageHandlerInMainThread.
+  ScriptState::Scope scope(m_scriptState.get());
+  return ScriptModule::compile(m_scriptState->isolate(), script, urlStr);
+}
+
+ScriptValue ModulatorImpl::instantiateModule(ScriptModule scriptModule) {
+  ScriptState::Scope scope(m_scriptState.get());
+  return scriptModule.instantiate(m_scriptState.get());
+}
+
+Vector<String> ModulatorImpl::moduleRequestsFromScriptModule(
+    ScriptModule scriptModule) {
+  ScriptState::Scope scope(m_scriptState.get());
+  return scriptModule.moduleRequests(m_scriptState.get());
+}
+
+void ModulatorImpl::executeModule(ScriptModule scriptModule) {
+  ScriptState::Scope scope(m_scriptState.get());
+  scriptModule.evaluate(m_scriptState.get());
+}
+
+DEFINE_TRACE(ModulatorImpl) {
+  visitor->trace(m_executionContext);
+  visitor->trace(m_fetcher);
+  visitor->trace(m_map);
+  visitor->trace(m_loaderRegistry);
+  visitor->trace(m_treeLinkerRegistry);
+  visitor->trace(m_scriptModuleResolver);
+}
+
+}  // namespace blink