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/* -*- 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 .
*/
#pragma once
#include <string>
#include <stdexcept>
#include <type_traits>
#include <utility>
#include <prewin.h>
#include <objbase.h>
#include <postwin.h>
namespace sal::systools
{
/* 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_;
};
struct COM_QUERY_TAG {} constexpr COM_QUERY;
struct COM_QUERY_THROW_TAG {} constexpr COM_QUERY_THROW;
template <typename TAG>
constexpr bool is_COM_query_tag
= std::is_same_v<TAG, COM_QUERY_TAG> || std::is_same_v<TAG, COM_QUERY_THROW_TAG>;
/* A simple COM smart pointer template */
template <typename T>
class COMReference
{
public:
/* Explicitly controllable whether AddRef will be called or not */
COMReference(T* comptr = nullptr, bool bAddRef = true) :
com_ptr_(comptr)
{
if (bAddRef)
addRef(com_ptr_);
}
COMReference(const COMReference<T>& other) :
COMReference(other.com_ptr_)
{
}
COMReference(COMReference<T>&& other) :
COMReference(std::exchange(other.com_ptr_, nullptr), false)
{
}
// Query from IUnknown*, using COM_QUERY or COM_QUERY_THROW tags
template <typename T2, typename TAG>
COMReference(const COMReference<T2>& p, TAG t)
: COMReference(p.template QueryInterface<T>(t))
{
}
COMReference<T>& operator=(const COMReference<T>& other)
{
return operator=(other.com_ptr_);
}
COMReference<T>& operator=(COMReference<T>&& other)
{
if (com_ptr_ != other.com_ptr_)
{
clear();
std::swap(com_ptr_, other.com_ptr_);
}
return *this;
}
COMReference<T>& operator=(T* comptr)
{
assign(comptr);
return *this;
}
~COMReference() { release(com_ptr_); }
template <typename T2, typename TAG, std::enable_if_t<is_COM_query_tag<TAG>, int> = 0>
COMReference<T2> QueryInterface(TAG) const
{
void* ip = nullptr;
HRESULT hr = E_FAIL;
if (com_ptr_)
hr = com_ptr_->QueryInterface(__uuidof(T2), &ip);
if constexpr (std::is_same_v<TAG, COM_QUERY_THROW_TAG>)
if (FAILED(hr))
throw ComError("QueryInterface failed: Interface not supported!", hr);
return { static_cast<T2*>(ip), false };
}
template <typename T2, typename TAG>
COMReference<T>& set(const COMReference<T2>& p, TAG t)
{
return operator=(p.template QueryInterface<T>(t));
}
HRESULT TryCoCreateInstance(REFCLSID clsid, IUnknown* pOuter = nullptr,
DWORD nCtx = CLSCTX_ALL)
{
T* ip;
HRESULT hr = ::CoCreateInstance(clsid, pOuter, nCtx, __uuidof(T),
reinterpret_cast<void**>(&ip));
if (SUCCEEDED(hr))
release(std::exchange(com_ptr_, ip));
return hr;
}
COMReference<T>& CoCreateInstance(REFCLSID clsid, IUnknown* pOuter = nullptr,
DWORD nCtx = CLSCTX_ALL)
{
HRESULT hr = TryCoCreateInstance(clsid, pOuter, nCtx);
if (FAILED(hr))
throw ComError("CoCreateInstance failed!", hr);
return *this;
}
HRESULT TryCoGetClassObject(REFCLSID clsid, DWORD nCtx = CLSCTX_ALL)
{
T* i;
HRESULT hr = ::CoGetClassObject(clsid, nCtx, nullptr, __uuidof(T),
reinterpret_cast<void**>(&i));
if (SUCCEEDED(hr))
release(std::exchange(com_ptr_, i));
return hr;
}
COMReference<T>& CoGetClassObject(REFCLSID clsid, DWORD nCtx = CLSCTX_ALL)
{
HRESULT hr = TryCoGetClassObject(clsid, nCtx);
if (FAILED(hr))
throw ComError("CoGetClassObject failed!", hr);
return *this;
}
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&()
{
clear();
return &com_ptr_;
}
T* get() const { return com_ptr_; }
operator T* () const { return get(); }
void clear() { assign(nullptr); }
bool is() const { return (com_ptr_ != nullptr); }
operator bool() const { return is(); }
private:
static void addRef(T* ptr)
{
if (ptr)
ptr->AddRef();
}
static void release(T* ptr)
{
if (ptr)
ptr->Release();
}
void assign(T* ptr)
{
if (com_ptr_ == ptr)
return;
addRef(ptr);
release(std::exchange(com_ptr_, ptr));
}
T* com_ptr_;
};
} // sal::systools
/* Typedefs for some popular COM interfaces */
typedef sal::systools::COMReference<IDataObject> IDataObjectPtr;
typedef sal::systools::COMReference<IStream> IStreamPtr;
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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