[ES6 modules] Introduce ModuleScript model object

third_party/WebKit/Source/core/dom/ModuleScript.h

Index: third_party/WebKit/Source/core/dom/ModuleScript.h
diff --git a/third_party/WebKit/Source/core/dom/ModuleScript.h b/third_party/WebKit/Source/core/dom/ModuleScript.h
new file mode 100644
index 0000000000000000000000000000000000000000..e8ba012fb7f6dded5dfd26c401517a1237deb7d0
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/ModuleScript.h
@@ -0,0 +1,93 @@
+// 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.
+
+#ifndef ModuleScript_h
+#define ModuleScript_h
+
+#include "bindings/core/v8/ScriptModule.h"
+#include "bindings/core/v8/ScriptValue.h"
+#include "core/fetch/ResourceLoaderOptions.h"
+#include "platform/heap/Handle.h"
+#include "platform/weborigin/KURL.h"
+#include "public/platform/WebURLRequest.h"
+
+namespace blink {
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-instantiation-state
+enum class InstantiationState {

[yhirano, 2017/01/19 04:17:04]

Isn't this too generic? Maybe ModuleInstantiationState is better?

[kouhei (in TOK), 2017/01/27 18:46:27]

Done.

+  Uninstantiated,
+  Errored,
+  Instantiated,
+};
+
+// ModuleScript is a model object for the "module script" spec concept.
+// https://html.spec.whatwg.org/multipage/webappapis.html#module-script
+class ModuleScript final : public GarbageCollectedFinalized<ModuleScript> {
+ public:
+  static ModuleScript* create(
+      ScriptModule record,
+      const KURL& baseURL,
+      const String& nonce,
+      ParserDisposition parserState,
+      WebURLRequest::FetchCredentialsMode credentialsMode) {
+    return new ModuleScript(record, baseURL, nonce, parserState,
+                            credentialsMode);
+  }
+  ~ModuleScript() = default;
+
+  ScriptModule record() { return m_record; }

[yhirano, 2017/01/19 04:17:04]

+const

[kouhei (in TOK), 2017/01/27 18:46:27]

Done.

+  const KURL& baseURL() { return m_baseURL; }

[yhirano, 2017/01/19 04:17:05]

+const

[kouhei (in TOK), 2017/01/27 18:46:27]

Done.

+
+  InstantiationState instantiationState() const { return m_instantiationState; }
+  void updateStateAfterInstantiation(ScriptValue maybeError);
+
+  ScriptValue instantiationError() { return m_instantiationError; }
+  void propagateUpstreamError(ScriptValue error);
+  void propagateUpstreamSuccess();
+
+  ParserDisposition parserState() const { return m_parserState; };
+  WebURLRequest::FetchCredentialsMode credentialsMode() const {
+    return m_credentialsMode;
+  }
+  const String& nonce() const { return m_nonce; }
+

[domenic, 2017/01/19 05:23:59]

I guess the spec's "settings object" (~ v8::Context) is not needed because V8
handles all the script execution? And you manage to architect the code so that
cases like
https://html.spec.whatwg.org/#hostresolveimportedmodule(referencingmodule,-sp...
step 3 get the module map a different way? Might be worth mentioning in a
comment in case someone is trying to do a direct-to-spec comparison.

[kouhei (in TOK), 2017/01/19 05:27:37]

We will use Modulator::m_scriptState->v8::Context. Currently, we always have
access to the corresponding Modulator when we want to operate, I've omit it.
Maybe I should add a comment.

[kouhei (in TOK), 2017/01/19 08:50:21]

The V8 callback for the abstract operation passes in v8::Context as its
argument, so I didn't need one there.

+  DEFINE_INLINE_TRACE() {}
+
+ private:
+  ModuleScript(ScriptModule record,
+               const KURL& baseURL,
+               const String& nonce,
+               ParserDisposition parserState,
+               WebURLRequest::FetchCredentialsMode credentialsMode)
+      : m_record(record),
+        m_baseURL(baseURL),
+        m_nonce(nonce),
+        m_parserState(parserState),
+        m_credentialsMode(credentialsMode) {}
+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-module-record
+  ScriptModule m_record;
+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-base-url
+  const KURL m_baseURL;
+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-instantiation-state
+  InstantiationState m_instantiationState = InstantiationState::Uninstantiated;
+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-instantiation-error
+  ScriptValue m_instantiationError;

[yhirano, 2017/01/19 04:17:04]

Having a ScriptValue is problematic because it can contain any value and create
a reference cycle.

[domenic, 2017/01/19 05:23:59]

I guess technically this can only be one of the errors given by
https://tc39.github.io/ecma262/#sec-moduledeclarationinstantiation, so
SyntaxError, TypeError (via HostResolveImportedModule), maybe a few more. But
that seems like it's baking in an assumption that's out of scope for this class;
having it as a dumb value holder (ScriptValue) seems better to me... I dunno.

[kouhei (in TOK), 2017/01/19 05:27:37]

Still trying to wrap around my head. I'm trying to figure out how V8 compilation
error is propagated to Blink.

+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-nonce
+  const String m_nonce;
+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-parser
+  const ParserDisposition m_parserState;
+
+  // https://html.spec.whatwg.org/multipage/webappapis.html#concept-module-script-credentials-mode
+  const WebURLRequest::FetchCredentialsMode m_credentialsMode;
+};
+
+}  // namespace blink
+
+#endif