docs/latex/wx/objectdataptr.tex

   1 \section{\class{wxObjectDataPtr<T>}}\label{wxobjectdataptr}
   2
   3 This is helper template class to avoid memleaks because of missing calls
   4 to \helpref{wxObjectRefData::DecRef}{wxobjectrefdatadecref}.
   5
   6 Despite the name this template can actually be used for any
   7 class implementing the reference counting interface and it
   8 does not use or depend on wxObject.
   9
  10 \wxheading{See also}
  11
  12 \helpref{wxObject}{wxobject},
  13 \helpref{wxObjectRefData}{wxobjectrefdata},
  14 \helpref{Reference counting}{trefcount}
  15
  16 \wxheading{Derived from}
  17
  18 No base class
  19
  20 \wxheading{Include files}
  21
  22 <object.h>
  23
  24 \wxheading{Data structures}
  25
  26 {\small%
  27 \begin{verbatim}
  28 typedef T element_type
  29 \end{verbatim}
  30 }%
  31
  32 \wxheading{Example}
  33
  34 \begin{verbatim}
  35
  36 // include file
  37
  38 class MyCarRefData: public wxObjectRefData
  39 {
  40 public:
  41     MyCarRefData()  { m_price = 0; }
  42
  43     MyCarRefData( const MyCarRefData& data )
  44         : wxObjectRefData()
  45     {
  46         m_price = data.m_price;
  47     }
  48
  49     bool operator == (const MyCarRefData& data) const
  50     {
  51         return m_price == data.m_price;
  52     }
  53
  54     void SetPrice( int price )  { m_price = price; }
  55     int GetPrice()              { return m_price; }
  56
  57 protected:
  58     int m_price;
  59 };
  60
  61 class MyCar
  62 {
  63 public:
  64     MyCar( int price );
  65     MyCar( const MyCar& data );
  66
  67     bool operator == ( const MyCar& car ) const;
  68     bool operator != (const MyCar& car) const { return !(*this == car); }
  69
  70     void SetPrice( int price );
  71     int GetPrice() const;
  72
  73     wxObjectRefPtr<MyCarRefData> m_data;
  74
  75 protected:
  76     void UnShare();
  77 };
  78
  79
  80 // implementation
  81
  82 MyCar::MyCar( int price )
  83 {
  84     m_data = new MyCarRefData;
  85     m_data.get()->SetPrice( price );
  86 }
  87
  88 MyCar::MyCar( const MyCar& car )
  89 {
  90     m_data.reset( car.m_data.get() );
  91 }
  92
  93 bool MyCar::operator == ( const MyCar& car ) const
  94 {
  95     if (m_data.get() == car.m_data.get()) return true;
  96
  97     return (*m_data.get() == *car.m_data.get());
  98 }
  99
 100 void MyCar::SetPrice( int price )
 101 {
 102     UnShare();
 103
 104     m_data.get()->SetPrice( price );
 105 }
 106
 107 int MyCar::GetPrice() const
 108 {
 109     return m_data.get()->GetPrice();
 110 }
 111
 112 void MyCar::UnShare()
 113 {
 114     if (m_data.get()->GetCount() == 1)
 115         return;
 116
 117     m_data.reset( new MyCarRefData( *m_data.get() ) );
 118 }
 119
 120 \end{verbatim}
 121
 122
 123 \latexignore{\rtfignore{\wxheading{Members}}}
 124
 125 \membersection{wxObjectDataPtr<T>::wxObjectDataPtr<T>}\label{wxobjectdataptrwxobjectdataptr}
 126
 127 \func{wxEXPLICIT}{wxObjectDataPtr<T>}{\param{T* }{ptr = NULL}}
 128
 129 Constructor. {\it ptr} is a pointer to the reference
 130 counted object to which this class points.
 131
 132 \func{}{wxObjectDataPtr<T>}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
 133
 134 This copy constructor increases the count of the reference
 135 counted object to which {\it tocopy} points and then this
 136 class will point to, as well.
 137
 138 \membersection{wxObjectDataPtr<T>::\destruct{wxObjectDataPtr<T>}}\label{wxobjectdataptrdtor}
 139
 140 \func{}{\destruct{wxObjectDataPtr<T>}}{\void}
 141
 142 Calls \helpref{DecRef}{wxobjectrefdatadecref} on the reference
 143 counted object to which this class points.
 144
 145 \membersection{wxObjectDataPtr<T>::operator->}\label{wxobjectdataptroperatorpointer}
 146
 147 \constfunc{T*}{operator->}{\void}
 148
 149 Gets a pointer to the reference counted object to which
 150 this class points. Same as \helpref{get}{wxobjectdataptrget}.
 151
 152 \membersection{wxObjectDataPtr<T>::operator=}\label{wxobjectdataptroperatorassign}
 153
 154 \func{wxObjectDataPtr<T>\& operator}{operator=}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
 155
 156 \func{wxObjectDataPtr<T>\& operator}{operator=}{\param{T* }{ptr}}
 157
 158 Assignment operators.
 159
 160 \membersection{wxObjectDataPtr<T>::get}\label{wxobjectdataptrget}
 161
 162 \constfunc{T*}{get}{\void}
 163
 164 Gets a pointer to the reference counted object to which
 165 this class points.
 166
 167 \membersection{wxObjectDataPtr<T>::reset}\label{wxobjectdataptrreset}
 168
 169 \func{void}{reset}{\param{T* }{ptr}}
 170
 171 Reset this class to {\it ptr} which points to a reference
 172 counted object.