/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this file,

 * You can obtain one at http://mozilla.org/MPL/2.0/. */

/**

 * A simplere nsIGlobalObject implementation that can be used to set up a new

 * global without anything interesting in it other than the JS builtins.  This

 * is safe to use on both mainthread and worker threads.

 */

#ifndef mozilla_dom_SimpleGlobalObject_h__

#define mozilla_dom_SimpleGlobalObject_h__

#include "nsIGlobalObject.h"

#include "nsWrapperCache.h"

#include "js/TypeDecls.h"

#include "nsISupportsImpl.h"

#include "nsCycleCollectionParticipant.h"

namespace mozilla {

namespace dom {

class SimpleGlobalObject : public nsIGlobalObject,

                           public nsWrapperCache

{

public:

  enum class GlobalType {

    BindingDetail, // Should only be used by DOM bindings code.

    WorkerDebuggerSandbox,

    NotSimpleGlobal // Sentinel to be used by BasicGlobalType.

  };

  // Create a new JS global object that can be used to do some work.  This

  // global will NOT have any DOM APIs exposed in it, will not be visible to the

  // debugger, and will not have a useful concept of principals, so don't try to

  // use it with any DOM objects.  Apart from that, running code with

  // side-effects is safe in this global.  Importantly, when you are first

  // handed this global it's guaranteed to have pristine built-ins.  The

  // corresponding nsIGlobalObject* for this global object will be a

  // SimpleGlobalObject of the type provided; JS_GetPrivate on the returned

  // JSObject* will return the SimpleGlobalObject*.

  //

  // If the provided prototype value is undefined, it is ignored.  If it's an

  // object or null, it's set as the prototype of the created global.  If it's

  // anything else, this function returns null.

  //

  // Note that creating new globals is not cheap and should not be done

  // gratuitously.  Please think carefully before you use this function.

  static JSObject* Create(GlobalType globalType,

                          JS::Handle<JS::Value> proto =

                            JS::UndefinedHandleValue);

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(SimpleGlobalObject,

                                                         nsIGlobalObject)

  // Gets the GlobalType of this SimpleGlobalObject.

  GlobalType Type() const

  {

    return mType;

  }

  // Gets the GlobalType of the SimpleGlobalObject for the given JSObject*, if

  // the given JSObject* is the global corresponding to a SimpleGlobalObject.

  // Oherwise, returns GlobalType::NotSimpleGlobal.

  static GlobalType SimpleGlobalType(JSObject* obj);

  virtual JSObject *GetGlobalJSObject() override

  {

    return GetWrapper();

  }

  virtual JSObject* WrapObject(JSContext* cx,

                               JS::Handle<JSObject*> aGivenProto) override

  {

    MOZ_CRASH("SimpleGlobalObject doesn't use DOM bindings!");

  }

private:

  SimpleGlobalObject(JSObject *global, GlobalType type)

    : mType(type)

  {

    SetWrapper(global);

  }

  virtual ~SimpleGlobalObject()

  {

    MOZ_ASSERT(!GetWrapperMaybeDead());

  }

  const GlobalType mType;

};

} // namespace dom

} // namespace mozilla

#endif /* mozilla_dom_SimpleGlobalObject_h__ */