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 #pragma once
  21
  22 #include <sal/config.h>
  23
  24 #include <source_location>
  25 #include <string>
  26 #include <string_view>
  27 #include <stdexcept>
  28 #include <type_traits>
  29 #include <utility>
  30
  31 #include <prewin.h>
  32 #include <objbase.h>
  33 #include <postwin.h>
  34
  35 namespace sal::systools
  36 {
  37     /* Simple exception class for propagating COM errors */
  38     class ComError : public std::runtime_error
  39     {
  40     public:
  41         ComError(std::string_view message, HRESULT hr,
  42                  const std::source_location& loc = std::source_location::current())
  43             : std::runtime_error(std::string(message))
  44             , hr_(hr)
  45             , loc_(loc)
  46         {}
  47
  48         HRESULT GetHresult() const { return hr_; }
  49         const std::source_location& GetLocation() const { return loc_; }
  50
  51     private:
  52         HRESULT hr_;
  53         std::source_location loc_;
  54     };
  55
  56     /* Convert failed HRESULT to thrown ComError */
  57     inline void ThrowIfFailed(HRESULT hr, std::string_view msg,
  58                               std::source_location loc = std::source_location::current())
  59     {
  60         if (FAILED(hr))
  61             throw ComError(msg, hr, loc);
  62     }
  63
  64     /* A guard class to call CoInitializeEx/CoUninitialize in proper pairs
  65      * See also: o3tl::safeCoInitializeEx doing dangerous re-initialization
  66      */
  67     class CoInitializeGuard
  68     {
  69     public:
  70         enum class WhenFailed
  71         {
  72             NoThrow, // do not throw
  73             Throw, // throw on failure
  74             Abort, // std::abort on failure
  75         };
  76         explicit CoInitializeGuard(DWORD dwCoInit, bool failChangeMode = false,
  77                                    WhenFailed whenFailed = WhenFailed::Throw)
  78         {
  79             HRESULT hr = ::CoInitializeEx(nullptr, dwCoInit);
  80             if (whenFailed != WhenFailed::NoThrow && FAILED(hr)
  81                 && (failChangeMode || hr != RPC_E_CHANGED_MODE))
  82             {
  83                 if (whenFailed == WhenFailed::Throw)
  84                     throw ComError("CoInitializeEx failed", hr);
  85                 else // if (whenFailed == Abort)
  86                     std::abort();
  87             }
  88             mbUninit = SUCCEEDED(hr);
  89         }
  90         CoInitializeGuard(const CoInitializeGuard&) = delete; // non-construction-copyable
  91         void operator=(const CoInitializeGuard&) = delete; // non-copyable
  92         ~CoInitializeGuard()
  93         {
  94             if (mbUninit)
  95                 ::CoUninitialize();
  96         }
  97
  98     private:
  99         bool mbUninit;
 100     };
 101
 102     struct COM_QUERY_TAG {} constexpr COM_QUERY;
 103     struct COM_QUERY_THROW_TAG : public COM_QUERY_TAG {} constexpr COM_QUERY_THROW;
 104
 105     /* A simple COM smart pointer template */
 106     template <typename T>
 107     class COMReference
 108     {
 109     public:
 110         /* Explicitly controllable whether AddRef will be called or not */
 111         COMReference(T* comptr = nullptr, bool bAddRef = true) :
 112             com_ptr_(comptr)
 113         {
 114             if (bAddRef)
 115                 addRef(com_ptr_);
 116         }
 117
 118         COMReference(const COMReference<T>& other) :
 119             COMReference(other.com_ptr_)
 120         {
 121         }
 122
 123         COMReference(COMReference<T>&& other) :
 124             COMReference(std::exchange(other.com_ptr_, nullptr), false)
 125         {
 126         }
 127
 128         // Query from IUnknown*, using COM_QUERY or COM_QUERY_THROW tags
 129         template <typename T2, typename TAG>
 130         COMReference(const COMReference<T2>& p, TAG t)
 131             : COMReference(p.template QueryInterface<T>(t))
 132         {
 133         }
 134
 135         // Using CoCreateInstance
 136         COMReference(REFCLSID clsid, IUnknown* pOuter = nullptr, DWORD nCtx = CLSCTX_ALL)
 137             : com_ptr_(nullptr)
 138         {
 139             ThrowIfFailed(CoCreateInstance(clsid, pOuter, nCtx), "CoCreateInstance failed");
 140         }
 141
 142         COMReference<T>& operator=(const COMReference<T>& other)
 143         {
 144             return operator=(other.com_ptr_);
 145         }
 146
 147         COMReference<T>& operator=(COMReference<T>&& other)
 148         {
 149             if (com_ptr_ != other.com_ptr_)
 150             {
 151                 clear();
 152                 std::swap(com_ptr_, other.com_ptr_);
 153             }
 154             return *this;
 155         }
 156
 157         COMReference<T>& operator=(T* comptr)
 158         {
 159             assign(comptr);
 160             return *this;
 161         }
 162
 163         ~COMReference() { release(com_ptr_); }
 164
 165         template <typename T2, typename TAG>
 166             requires std::is_base_of_v<COM_QUERY_TAG, TAG>
 167         COMReference<T2> QueryInterface(TAG) const
 168         {
 169             T2* ip = nullptr;
 170             HRESULT hr = E_POINTER;
 171             if (com_ptr_)
 172                 hr = com_ptr_->QueryInterface(&ip);
 173
 174             if constexpr (std::is_same_v<TAG, COM_QUERY_THROW_TAG>)
 175                 ThrowIfFailed(hr, "QueryInterface failed");
 176
 177             return { ip, false };
 178         }
 179
 180         template <typename T2, typename TAG>
 181         COMReference<T>& set(const COMReference<T2>& p, TAG t)
 182         {
 183             return operator=(p.template QueryInterface<T>(t));
 184         }
 185
 186         HRESULT CoCreateInstance(REFCLSID clsid, IUnknown* pOuter = nullptr,
 187                                  DWORD nCtx = CLSCTX_ALL)
 188         {
 189             T* ip;
 190             HRESULT hr = ::CoCreateInstance(clsid, pOuter, nCtx, IID_PPV_ARGS(&ip));
 191             if (SUCCEEDED(hr))
 192                 release(std::exchange(com_ptr_, ip));
 193             return hr;
 194         }
 195
 196         HRESULT CoGetClassObject(REFCLSID clsid, DWORD nCtx = CLSCTX_ALL)
 197         {
 198             T* ip;
 199             HRESULT hr = ::CoGetClassObject(clsid, nCtx, nullptr, IID_PPV_ARGS(&ip));
 200             if (SUCCEEDED(hr))
 201                 release(std::exchange(com_ptr_, ip));
 202             return hr;
 203         }
 204
 205         T* operator->() const { return com_ptr_; }
 206
 207         T& operator*() const { return *com_ptr_; }
 208
 209         /* Necessary for assigning com_ptr_ from functions like
 210            CoCreateInstance which require a 'void**' */
 211         T** operator&()
 212         {
 213             clear();
 214             return &com_ptr_;
 215         }
 216
 217         T* get() const { return com_ptr_; }
 218         operator T* () const { return get(); }
 219
 220         void clear() { assign(nullptr); }
 221
 222         bool is() const { return (com_ptr_ != nullptr); }
 223         operator bool() const { return is(); }
 224
 225     private:
 226         static void addRef(T* ptr)
 227         {
 228             if (ptr)
 229                 ptr->AddRef();
 230         }
 231
 232         static void release(T* ptr)
 233         {
 234             if (ptr)
 235                 ptr->Release();
 236         }
 237
 238         void assign(T* ptr)
 239         {
 240             if (com_ptr_ == ptr)
 241                 return;
 242             addRef(ptr);
 243             release(std::exchange(com_ptr_, ptr));
 244         }
 245
 246         T* com_ptr_;
 247     };
 248
 249     // A class to use with functions taking an out pointer argument,
 250     // that needs to be freed with CoTaskMemFree - like SHGetKnownFolderPath
 251     template <typename T> class CoTaskMemAllocated
 252     {
 253     public:
 254         ~CoTaskMemAllocated() { CoTaskMemFree(m_pv); }
 255
 256         T** operator&()
 257         {
 258             CoTaskMemFree(std::exchange(m_pv, nullptr));
 259             return &m_pv;
 260         };
 261
 262         operator T*() { return m_pv; }
 263
 264     private:
 265         T* m_pv = nullptr;
 266     };
 267
 268 } // sal::systools
 269
 270 /* Typedefs for some popular COM interfaces */
 271 typedef sal::systools::COMReference<IDataObject> IDataObjectPtr;
 272
 273 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */