[ES6 modules] Document ScriptModule

third_party/WebKit/Source/bindings/core/v8/ScriptModule.h

 // 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 ScriptModule_h
 #define ScriptModule_h
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/SharedPersistent.h"
 #include "core/CoreExport.h"
 #include "v8/include/v8.h"
 #include "wtf/Allocator.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
+// ScriptModule wraps a handle to a v8::Module for use in core.
+//
+// Using ScriptModules needs a ScriptState and its scope to operate in. You
+// should always provide the same ScriptState and not try to reuse ScriptModules
+// across different contexts.
+// Currently all ScriptModule users can easily access its context Modulator, so
+// we use it to fill ScriptState in.

[haraken, 2017/04/04 05:28:26]

Would it be nicer to pass in the ScriptState to ScriptModule's constructor, save
it in ScriptModule's member and then use it for instantiate & evaluate?

[kouhei (in TOK), 2017/04/04 06:39:48]

I'd like to try ScriptModule lightweight w/o ScriptState for now, as then
Modulator will have to check ScriptState* is valid every time.

 class CORE_EXPORT ScriptModule final {
   DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
 
  public:
   static ScriptModule compile(v8::Isolate*,
                               const String& source,
                               const String& fileName);
 
   ScriptModule() {}
   ScriptModule(const ScriptModule& module) : m_module(module.m_module) {}
   ~ScriptModule();
 
   bool instantiate(ScriptState*);
   void evaluate(ScriptState*);
 
   bool isNull() const { return m_module->isEmpty(); }
 
  private:
   ScriptModule(v8::Isolate*, v8::Local<v8::Module>);
 
   RefPtr<SharedPersistent<v8::Module>> m_module;
 };
 
 }  // namespace blink
 
 #endif  // ScriptModule_h