/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/* vim: set ts=8 sts=4 et sw=4 tw=99: */

/* 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 xpcObjectHelper_h

#define xpcObjectHelper_h

// Including 'windows.h' will #define GetClassInfo to something else.

#ifdef XP_WIN

#ifdef GetClassInfo

#undef GetClassInfo

#endif

#endif

#include "mozilla/Attributes.h"

#include <stdint.h>

#include "nsCOMPtr.h"

#include "nsIClassInfo.h"

#include "nsISupports.h"

#include "nsIXPCScriptable.h"

#include "nsWrapperCache.h"

class xpcObjectHelper

{

public:

    explicit xpcObjectHelper(nsISupports* aObject, nsWrapperCache* aCache = nullptr)

      : mObject(aObject)

      , mCache(aCache)

    {

        if (!mCache && aObject) {

            CallQueryInterface(aObject, &mCache);

        }

    }

    nsISupports* Object()

    {

        return mObject;

    }

    nsIClassInfo* GetClassInfo()

    {

        if (!mClassInfo) {

            mClassInfo = do_QueryInterface(mObject);

        }

        return mClassInfo;

    }

    // We assert that we can reach an nsIXPCScriptable somehow.

    uint32_t GetScriptableFlags()

    {

        nsCOMPtr<nsIXPCScriptable> sinfo = do_QueryInterface(mObject);

        // We should have something by now.

        MOZ_ASSERT(sinfo);

        // Grab the flags.

        return sinfo->GetScriptableFlags();

    }

    nsWrapperCache* GetWrapperCache()

    {

        return mCache;

    }

private:

    xpcObjectHelper(xpcObjectHelper& aOther) = delete;

    nsISupports* MOZ_UNSAFE_REF("xpcObjectHelper has been specifically optimized "

                                "to avoid unnecessary AddRefs and Releases. "

                                "(see bug 565742)") mObject;

    nsWrapperCache*          mCache;

    nsCOMPtr<nsIClassInfo>   mClassInfo;

};

#endif