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 \begin{verbatim}
  27 typedef T element\_type
  28 \end{verbatim}}
  29
  30 \wxheading{Example}
  31
  32 \begin{verbatim}
  33
  34 // include file
  35
  36 class MyCarRefData: public wxObjectRefData
  37 {
  38 public:
  39     MyCarRefData()  { m_price = 0; }
  40
  41     MyCarRefData( const MyCarRefData& data )
  42         : wxObjectRefData()
  43     {
  44         m_price = data.m_price;
  45     }
  46
  47     bool operator == (const MyCarRefData& data) const
  48     {
  49         return m_price == data.m_price;
  50     }
  51
  52     void SetPrice( int price )  { m_price = price; }
  53     int GetPrice()              { return m_price; }
  54
  55 protected:
  56     int m_price;
  57 };
  58
  59 class MyCar
  60 {
  61 public:
  62     MyCar( int price );
  63     MyCar( const MyCar& data );
  64
  65     bool operator == ( const MyCar& car ) const;
  66     bool operator != (const MyCar& car) const { return !(*this == car); }
  67
  68     void SetPrice( int price );
  69     int GetPrice() const;
  70
  71     wxObjectRefPtr<MyCarRefData> m_data;
  72
  73 protected:
  74     void UnShare();
  75 };
  76
  77
  78 // implementation
  79
  80 MyCar::MyCar( int price )
  81 {
  82     m_data = new MyCarRefData;
  83     m_data.get()->SetPrice( price );
  84 }
  85
  86 MyCar::MyCar( const MyCar& car )
  87 {
  88     m_data.reset( car.m_data.get() );
  89 }
  90
  91 bool MyCar::operator == ( const MyCar& car ) const
  92 {
  93     if (m_data.get() == car.m_data.get()) return true;
  94
  95     return (*m_data.get() == *car.m_data.get());
  96 }
  97
  98 void MyCar::SetPrice( int price )
  99 {
 100     UnShare();
 101
 102     m_data.get()->SetPrice( price );
 103 }
 104
 105 int MyCar::GetPrice() const
 106 {
 107     return m_data.get()->GetPrice();
 108 }
 109
 110 void MyCar::UnShare()
 111 {
 112     if (m_data.get()->GetCount() == 1)
 113         return;
 114
 115     m_data.reset( new MyCarRefData( *m_data.get() ) );
 116 }
 117
 118 \end{verbatim}
 119
 120
 121 \latexignore{\rtfignore{\wxheading{Members}}}
 122
 123 \membersection{wxObjectDataPtr<T>::wxObjectDataPtr<T>}\label{wxobjectdataptrwxobjectdataptr}
 124
 125 \func{wxEXPLICIT}{wxObjectDataPtr<T>}{\param{T* }{ptr = NULL}}
 126
 127 Constructor. {\it ptr} is a pointer to the reference
 128 counted object to which this class points.
 129
 130 \func{}{wxObjectDataPtr<T>}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
 131
 132 This copy constructor increases the count of the reference
 133 counted object to which {\it tocopy} points and then this
 134 class will point to, as well.
 135
 136 \membersection{wxObjectDataPtr<T>::\destruct{wxObjectDataPtr<T>}}\label{wxobjectdataptrdtor}
 137
 138 \func{}{\destruct{wxObjectDataPtr<T>}}{\void}
 139
 140 Calls \helpref{DecRef}{wxobjectrefdatadecref} on the reference
 141 counted object to which this class points.
 142
 143 \membersection{wxObjectDataPtr<T>::operator->}\label{wxobjectdataptroperatorpointer}
 144
 145 \constfunc{T*}{operator->}{\void}
 146
 147 Gets a pointer to the reference counted object to which
 148 this class points. Same as \helpref{get}{wxobjectdataptrget}.
 149
 150 \membersection{wxObjectDataPtr<T>::operator=}\label{wxobjectdataptroperatorassign}
 151
 152 \func{wxObjectDataPtr<T>\& operator}{operator=}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
 153
 154 \func{wxObjectDataPtr<T>\& operator}{operator=}{\param{T* }{ptr}}
 155
 156 Assignment operators.
 157
 158 \membersection{wxObjectDataPtr<T>::get}\label{wxobjectdataptrget}
 159
 160 \constfunc{T*}{get}{\void}
 161
 162 Gets a pointer to the reference counted object to which
 163 this class points.
 164
 165 \membersection{wxObjectDataPtr<T>::reset}\label{wxobjectdataptrreset}
 166
 167 \func{void}{reset}{\param{T* }{ptr}}
 168
 169 Reset this class to {\it ptr} which points to a reference
 170 counted object.