sal/inc/systools/win32/comtools.hxx

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  30
  31 #pragma once
  32
  33 #include <string>
  34 #include <stdexcept>
  35 #if defined _MSC_VER
  36 #pragma warning(push,1)
  37 #endif
  38 #include <objbase.h>
  39 #if defined _MSC_VER
  40 #pragma warning(pop)
  41 #endif
  42
  43 namespace sal
  44 {
  45 namespace systools
  46 {
  47     typedef int HRESULT;
  48
  49     /* Simple exception class for propagating COM errors */
  50     class ComError : public std::runtime_error
  51     {
  52     public:
  53         ComError(const std::string& message, HRESULT hr) :
  54             std::runtime_error(message),
  55             hr_(hr)
  56         {}
  57
  58         HRESULT GetHresult() const
  59         {
  60             return hr_;
  61         }
  62
  63     private:
  64         HRESULT hr_;
  65     };
  66
  67     /* A simple COM smart pointer template */
  68     template <typename T>
  69     class COMReference
  70     {
  71     public:
  72         COMReference() :
  73             com_ptr_(NULL)
  74         {
  75         }
  76
  77         explicit COMReference(T* comptr) :
  78             com_ptr_(comptr)
  79         {
  80             addRef();
  81         }
  82
  83         /* Explicitly controllable whether AddRef will be called or not */
  84         COMReference(T* comptr, bool bAddRef) :
  85             com_ptr_(comptr)
  86         {
  87             if (bAddRef)
  88                 addRef();
  89         }
  90
  91         COMReference(const COMReference<T>& other) :
  92             com_ptr_(other.com_ptr_)
  93         {
  94             addRef();
  95         }
  96
  97         COMReference<T>& operator=(const COMReference<T>& other)
  98         {
  99             if (other.com_ptr_)
 100                 other.com_ptr_->AddRef();
 101             release();
 102             com_ptr_ = other.com_ptr_;
 103             return *this;
 104         }
 105
 106         COMReference<T>& operator=(T* comptr)
 107         {
 108             release();
 109             com_ptr_ = comptr;
 110             addRef();
 111             return *this;
 112         }
 113
 114         ~COMReference()
 115         {
 116             release();
 117         }
 118
 119         template<typename InterfaceType>
 120         COMReference<InterfaceType> QueryInterface(REFIID iid)
 121         {
 122             COMReference<InterfaceType> ip;
 123             HRESULT hr = E_FAIL;
 124             if (com_ptr_)
 125                 hr = com_ptr_->QueryInterface(iid, reinterpret_cast<LPVOID*>(&ip));
 126
 127             if (FAILED(hr))
 128                 throw ComError("QueryInterface failed: Interface not supported!", hr);
 129
 130             return ip;
 131         }
 132
 133         T* operator->() const
 134         {
 135             return com_ptr_;
 136         }
 137
 138         T& operator*() const
 139         {
 140             return *com_ptr_;
 141         }
 142
 143         /* Necessary for assigning com_ptr_ from functions like
 144            CoCreateInstance which require a 'void**' */
 145         T** operator&()
 146         {
 147             release();
 148             com_ptr_ = NULL;
 149             return &com_ptr_;
 150         }
 151
 152         T* get() const
 153         {
 154             return com_ptr_;
 155         }
 156
 157         COMReference<T>& clear()
 158         {
 159             release();
 160             com_ptr_ = NULL;
 161             return *this;
 162         }
 163
 164         bool is() const
 165         {
 166             return (com_ptr_ != NULL);
 167         }
 168
 169     private:
 170         ULONG addRef()
 171         {
 172             ULONG cnt = 0;
 173             if (com_ptr_)
 174                 cnt = com_ptr_->AddRef();
 175             return cnt;
 176         }
 177
 178         ULONG release()
 179         {
 180             ULONG cnt = 0;
 181             if (com_ptr_)
 182                 cnt = com_ptr_->Release();
 183             return cnt;
 184         }
 185
 186     private:
 187         T* com_ptr_;
 188     };
 189
 190 } // systools
 191 } // sal
 192
 193 /* Typedefs for some popular COM interfaces */
 194 typedef sal::systools::COMReference<IDataObject> IDataObjectPtr;
 195 typedef sal::systools::COMReference<IStream> IStreamPtr;
 196 typedef sal::systools::COMReference<IEnumFORMATETC> IEnumFORMATETCPtr;
 197