/* -*- 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/. */

#ifndef mozilla_dom_SpiderMonkeyInterface_h

#define mozilla_dom_SpiderMonkeyInterface_h

#include "jsapi.h"

#include "jsfriendapi.h"

#include "js/TracingAPI.h"

namespace mozilla {

namespace dom {

/*

 * Class that just handles the JSObject storage and tracing for spidermonkey

 * interfaces

 */

struct SpiderMonkeyInterfaceObjectStorage {

 protected:

  JSObject* mImplObj;

  JSObject* mWrappedObj;

  SpiderMonkeyInterfaceObjectStorage()

      : mImplObj(nullptr), mWrappedObj(nullptr) {}

  SpiderMonkeyInterfaceObjectStorage(

      SpiderMonkeyInterfaceObjectStorage&& aOther)

      : mImplObj(aOther.mImplObj), mWrappedObj(aOther.mWrappedObj) {

    aOther.mImplObj = nullptr;

    aOther.mWrappedObj = nullptr;

  }

 public:

  inline void TraceSelf(JSTracer* trc) {

    JS::UnsafeTraceRoot(trc, &mImplObj,

                        "SpiderMonkeyInterfaceObjectStorage.mImplObj");

    JS::UnsafeTraceRoot(trc, &mWrappedObj,

                        "SpiderMonkeyInterfaceObjectStorage.mWrappedObj");

  }

  inline bool inited() const { return !!mImplObj; }

  inline bool WrapIntoNewCompartment(JSContext* cx) {

    return JS_WrapObject(

        cx, JS::MutableHandle<JSObject*>::fromMarkedLocation(&mWrappedObj));

  }

  inline JSObject* Obj() const {

    MOZ_ASSERT(inited());

    return mWrappedObj;

  }

 private:

  SpiderMonkeyInterfaceObjectStorage(

      const SpiderMonkeyInterfaceObjectStorage&) = delete;

};

// A class for rooting an existing SpiderMonkey Interface struct

template <typename InterfaceType>

class MOZ_RAII SpiderMonkeyInterfaceRooter : private JS::CustomAutoRooter {

 public:

  template <typename CX>

  SpiderMonkeyInterfaceRooter(

      const CX& cx, InterfaceType* aInterface MOZ_GUARD_OBJECT_NOTIFIER_PARAM)

      : JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),

        mInterface(aInterface) {}

  virtual void trace(JSTracer* trc) override { mInterface->TraceSelf(trc); }

 private:

  SpiderMonkeyInterfaceObjectStorage* const mInterface;

};

// And a specialization for dealing with nullable SpiderMonkey interfaces

template <typename Inner>

struct Nullable;

template <typename InterfaceType>

class MOZ_RAII SpiderMonkeyInterfaceRooter<Nullable<InterfaceType>>

    : private JS::CustomAutoRooter {

 public:

  template <typename CX>

  SpiderMonkeyInterfaceRooter(const CX& cx, Nullable<InterfaceType>* aInterface

                                                MOZ_GUARD_OBJECT_NOTIFIER_PARAM)

      : JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),

        mInterface(aInterface) {}

  virtual void trace(JSTracer* trc) override {

    if (!mInterface->IsNull()) {

      mInterface->Value().TraceSelf(trc);

    }

  }

 private:

  Nullable<InterfaceType>* const mInterface;

};

// Class for easily setting up a rooted SpiderMonkey interface object on the

// stack

template <typename InterfaceType>

class MOZ_RAII RootedSpiderMonkeyInterface final

    : public InterfaceType,

      private SpiderMonkeyInterfaceRooter<InterfaceType> {

 public:

  template <typename CX>

  explicit RootedSpiderMonkeyInterface(

      const CX& cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)

      : InterfaceType(),

        SpiderMonkeyInterfaceRooter<InterfaceType>(

            cx, this MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT) {}

  template <typename CX>

  RootedSpiderMonkeyInterface(const CX& cx,

                              JSObject* obj MOZ_GUARD_OBJECT_NOTIFIER_PARAM)

      : InterfaceType(obj),

        SpiderMonkeyInterfaceRooter<InterfaceType>(

            cx, this MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT) {}

};

}  // namespace dom

}  // namespace mozilla

#endif /* mozilla_dom_SpiderMonkeyInterface_h */