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

third_party/WebKit/Source/bindings/core/v8/ScriptModule.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 "bindings/core/v8/ScriptModule.h"
+
+#include "bindings/core/v8/ScriptModuleResolver.h"
+#include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8PerContextData.h"
+#include "core/dom/Modulator.h"
+
+namespace blink {
+
+ScriptModule::ScriptModule(v8::Isolate* isolate, v8::Local<v8::Module> module)
+    : m_module(SharedPersistent<v8::Module>::create(module, isolate)),
+      m_identityHash(static_cast<unsigned>(module->GetIdentityHash())) {}
+
+ScriptModule::~ScriptModule() {}
+
+ScriptModule ScriptModule::compile(v8::Isolate* isolate,
+                                   const String& source,
+                                   const String& fileName) {
+  // TODO(adamk): Pass more info into ScriptOrigin.
+  v8::ScriptOrigin origin(v8String(isolate, fileName));
+  v8::ScriptCompiler::Source scriptSource(v8String(isolate, source), origin);
+  v8::TryCatch tryCatch(isolate);
+  tryCatch.SetVerbose(true);
+  v8::Local<v8::Module> module;
+  // TODO(kouhei): Add a helper function in V8ScriptRunner so that we can
+  // centralize all code to compile & run scripts in V8ScriptRunner.
+  if (!v8Call(v8::ScriptCompiler::CompileModule(isolate, &scriptSource), module,
+              tryCatch)) {
+    // TODO(adamk): Signal failure somehow.
+    return ScriptModule(isolate, module);
+  }
+  return ScriptModule(isolate, module);
+}
+
+v8::MaybeLocal<v8::Module> ScriptModule::resolveModuleCallback(
+    v8::Local<v8::Context> context,
+    v8::Local<v8::String> specifier,
+    v8::Local<v8::Module> referrer) {
+  v8::Isolate* isolate = context->GetIsolate();
+  Modulator* modulator = V8PerContextData::from(context)->modulator();
+  DCHECK(modulator);
+
+  ScriptModule referrerRecord(isolate, referrer);
+  // TODO(kouhei): Construct ScriptModuleIdentifier w/o creating extra
+  // Persistent.
+  ScriptModule resolved = modulator->scriptModuleResolver()->resolve(
+      toCoreStringWithNullCheck(specifier), referrerRecord.identifier());
+  if (resolved.isNull())
+    return v8::MaybeLocal<v8::Module>();
+
+  return v8::MaybeLocal<v8::Module>(resolved.m_module->newLocal(isolate));
+}
+
+bool ScriptModule::instantiate(ScriptState* scriptState) {
+  DCHECK(!isNull());
+  v8::Local<v8::Context> context = scriptState->context();
+  // TODO(adamk): pass in a real callback.
+  return m_module->newLocal(scriptState->isolate())
+      ->Instantiate(context, &resolveModuleCallback);
+}
+
+void ScriptModule::evaluate(ScriptState* scriptState) {
+  v8::TryCatch tryCatch(scriptState->isolate());
+  tryCatch.SetVerbose(true);
+  v8::Local<v8::Value> result;
+  if (!v8Call(m_module->newLocal(scriptState->isolate())
+                  ->Evaluate(scriptState->context()),
+              result, tryCatch)) {
+    // TODO(adamk): report error
+  }
+}
+
+Vector<String> ScriptModule::moduleRequests(ScriptState* scriptState) {
+  if (isNull())
+    return Vector<String>();
+
+  v8::Local<v8::Module> module = m_module->newLocal(scriptState->isolate());

[dominicc (has gone to gerrit), 2017/01/11 03:23:47]

HandleScope here?

[kouhei (in TOK), 2017/01/17 05:26:12]

Provided by caller.

+
+  Vector<String> ret;
+
+  int length = module->GetModuleRequestsLength();
+  ret.reserveInitialCapacity(length);
+  for (int i = 0; i < length; ++i) {
+    v8::Local<v8::String> v8Name = module->GetModuleRequest(i);
+    String name = toCoreStringWithNullCheck(v8Name);

[dominicc (has gone to gerrit), 2017/01/11 03:23:47]

Just toCoreString? Why would you expect null?

[kouhei (in TOK), 2017/01/17 05:26:12]

Done.

+    ret.push_back(name);
+  }
+  return ret;
+}
+
+ScriptModuleIdentifier ScriptModule::identifier() {
+  if (isNull())
+    return ScriptModuleIdentifier();
+
+  return ScriptModuleIdentifier(m_module, m_identityHash);
+}
+
+}  // namespace blink