include/systools/win32/comtools.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_SYSTOOLS_WIN32_COMTOOLS_HXX
  21 #define INCLUDED_SYSTOOLS_WIN32_COMTOOLS_HXX
  22
  23 #include <string>
  24 #include <stdexcept>
  25 #if defined _MSC_VER
  26 #pragma warning(push,1)
  27 #endif
  28 #include <objbase.h>
  29 #if defined _MSC_VER
  30 #pragma warning(pop)
  31 #endif
  32
  33 namespace sal
  34 {
  35 namespace systools
  36 {
  37     typedef int HRESULT;
  38
  39     /* Simple exception class for propagating COM errors */
  40     class ComError : public std::runtime_error
  41     {
  42     public:
  43         ComError(const std::string& message, HRESULT hr) :
  44             std::runtime_error(message),
  45             hr_(hr)
  46         {}
  47
  48         HRESULT GetHresult() const
  49         {
  50             return hr_;
  51         }
  52
  53     private:
  54         HRESULT hr_;
  55     };
  56
  57     /* A simple COM smart pointer template */
  58     template <typename T>
  59     class COMReference
  60     {
  61     public:
  62         COMReference() :
  63             com_ptr_(NULL)
  64         {
  65         }
  66
  67         explicit COMReference(T* comptr) :
  68             com_ptr_(comptr)
  69         {
  70             addRef();
  71         }
  72
  73         /* Explicitly controllable whether AddRef will be called or not */
  74         COMReference(T* comptr, bool bAddRef) :
  75             com_ptr_(comptr)
  76         {
  77             if (bAddRef)
  78                 addRef();
  79         }
  80
  81         COMReference(const COMReference<T>& other) :
  82             com_ptr_(other.com_ptr_)
  83         {
  84             addRef();
  85         }
  86
  87         COMReference<T>& operator=(const COMReference<T>& other)
  88         {
  89             if (other.com_ptr_)
  90                 other.com_ptr_->AddRef();
  91             release();
  92             com_ptr_ = other.com_ptr_;
  93             return *this;
  94         }
  95
  96         COMReference<T>& operator=(T* comptr)
  97         {
  98             release();
  99             com_ptr_ = comptr;
 100             addRef();
 101             return *this;
 102         }
 103
 104         ~COMReference()
 105         {
 106             release();
 107         }
 108
 109         template<typename InterfaceType>
 110         COMReference<InterfaceType> QueryInterface(REFIID iid)
 111         {
 112             COMReference<InterfaceType> ip;
 113             HRESULT hr = E_FAIL;
 114             if (com_ptr_)
 115                 hr = com_ptr_->QueryInterface(iid, reinterpret_cast<LPVOID*>(&ip));
 116
 117             if (FAILED(hr))
 118                 throw ComError("QueryInterface failed: Interface not supported!", hr);
 119
 120             return ip;
 121         }
 122
 123         T* operator->() const
 124         {
 125             return com_ptr_;
 126         }
 127
 128         T& operator*() const
 129         {
 130             return *com_ptr_;
 131         }
 132
 133         /* Necessary for assigning com_ptr_ from functions like
 134            CoCreateInstance which require a 'void**' */
 135         T** operator&()
 136         {
 137             release();
 138             com_ptr_ = NULL;
 139             return &com_ptr_;
 140         }
 141
 142         T* get() const
 143         {
 144             return com_ptr_;
 145         }
 146
 147         COMReference<T>& clear()
 148         {
 149             release();
 150             com_ptr_ = NULL;
 151             return *this;
 152         }
 153
 154         bool is() const
 155         {
 156             return (com_ptr_ != NULL);
 157         }
 158
 159     private:
 160         ULONG addRef()
 161         {
 162             ULONG cnt = 0;
 163             if (com_ptr_)
 164                 cnt = com_ptr_->AddRef();
 165             return cnt;
 166         }
 167
 168         ULONG release()
 169         {
 170             ULONG cnt = 0;
 171             if (com_ptr_)
 172                 cnt = com_ptr_->Release();
 173             return cnt;
 174         }
 175
 176     private:
 177         T* com_ptr_;
 178     };
 179
 180 } // systools
 181 } // sal
 182
 183 /* Typedefs for some popular COM interfaces */
 184 typedef sal::systools::COMReference<IDataObject> IDataObjectPtr;
 185 typedef sal::systools::COMReference<IStream> IStreamPtr;
 186 typedef sal::systools::COMReference<IEnumFORMATETC> IEnumFORMATETCPtr;
 187
 188 #endif // INCLUDED_SYSTOOLS_WIN32_COMTOOLS_HXX
 189
 190 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */