/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * 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/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#ifndef INCLUDED_SYSTOOLS_WIN32_COMTOOLS_HXX
#define INCLUDED_SYSTOOLS_WIN32_COMTOOLS_HXX

#include <string>
#include <stdexcept>
#include <objbase.h>

namespace sal
{
namespace systools
{
    typedef int HRESULT;

    /* Simple exception class for propagating COM errors */
    class ComError : public std::runtime_error
    {
    public:
        ComError(const std::string& message, HRESULT hr) :
            std::runtime_error(message),
            hr_(hr)
        {}

        HRESULT GetHresult() const
        {
            return hr_;
        }

    private:
        HRESULT hr_;
    };

    /* A simple COM smart pointer template */
    template <typename T>
    class COMReference
    {
    public:
        COMReference() :
            com_ptr_(NULL)
        {
        }

        explicit COMReference(T* comptr) :
            com_ptr_(comptr)
        {
            addRef();
        }

        /* Explicitly controllable whether AddRef will be called or not */
        COMReference(T* comptr, bool bAddRef) :
            com_ptr_(comptr)
        {
            if (bAddRef)
                addRef();
        }

        COMReference(const COMReference<T>& other) :
            com_ptr_(other.com_ptr_)
        {
            addRef();
        }

        COMReference<T>& operator=(const COMReference<T>& other)
        {
            if (other.com_ptr_)
                other.com_ptr_->AddRef();
            release();
            com_ptr_ = other.com_ptr_;
            return *this;
        }

        COMReference<T>& operator=(T* comptr)
        {
            release();
            com_ptr_ = comptr;
            addRef();
            return *this;
        }

        ~COMReference()
        {
            release();
        }

        template<typename InterfaceType>
        COMReference<InterfaceType> QueryInterface(REFIID iid)
        {
            COMReference<InterfaceType> ip;
            HRESULT hr = E_FAIL;
            if (com_ptr_)
                hr = com_ptr_->QueryInterface(iid, reinterpret_cast<LPVOID*>(&ip));

            if (FAILED(hr))
                throw ComError("QueryInterface failed: Interface not supported!", hr);

            return ip;
        }

        T* operator->() const
        {
            return com_ptr_;
        }

        T& operator*() const
        {
            return *com_ptr_;
        }

        /* Necessary for assigning com_ptr_ from functions like
           CoCreateInstance which require a 'void**' */
        T** operator&()
        {
            release();
            com_ptr_ = NULL;
            return &com_ptr_;
        }

        T* get() const
        {
            return com_ptr_;
        }

        COMReference<T>& clear()
        {
            release();
            com_ptr_ = NULL;
            return *this;
        }

        bool is() const
        {
            return (com_ptr_ != NULL);
        }

    private:
        ULONG addRef()
        {
            ULONG cnt = 0;
            if (com_ptr_)
                cnt = com_ptr_->AddRef();
            return cnt;
        }

        ULONG release()
        {
            ULONG cnt = 0;
            if (com_ptr_)
                cnt = com_ptr_->Release();
            return cnt;
        }

    private:
        T* com_ptr_;
    };

} // systools
} // sal

/* Typedefs for some popular COM interfaces */
typedef sal::systools::COMReference<IDataObject> IDataObjectPtr;
typedef sal::systools::COMReference<IStream> IStreamPtr;

#endif // INCLUDED_SYSTOOLS_WIN32_COMTOOLS_HXX

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