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
  64     bool operator == ( const MyCar& car ) const;
  65     bool operator != (const MyCar& car) const { return !(*this == car); }
  66
  67     void SetPrice( int price );
  68     int GetPrice() const;
  69
  70     wxObjectRefPtr<MyCarRefData> m_data;
  71
  72 protected:
  73     void UnShare();
  74 };
  75
  76
  77 // implementation
  78
  79 MyCar::MyCar( int price )
  80 {
  81     m_data = new MyCarRefData;
  82     m_data.get()->SetPrice( price );
  83 }
  84
  85 bool MyCar::operator == ( const MyCar& car ) const
  86 {
  87     if (m_data.get() == car.m_data.get()) return true;
  88
  89     return (*m_data.get() == *car.m_data.get());
  90 }
  91
  92 void MyCar::SetPrice( int price )
  93 {
  94     UnShare();
  95
  96     m_data.get()->SetPrice( price );
  97 }
  98
  99 int MyCar::GetPrice() const
 100 {
 101     return m_data.get()->GetPrice();
 102 }
 103
 104 void MyCar::UnShare()
 105 {
 106     if (m_data.get()->GetCount() == 1)
 107         return;
 108
 109     m_data.reset( new MyCarRefData( *m_data.get() ) );
 110 }
 111
 112 \end{verbatim}
 113
 114
 115 \latexignore{\rtfignore{\wxheading{Members}}}
 116
 117 \membersection{wxObjectDataPtr<T>::wxObjectDataPtr<T>}\label{wxobjectdataptrwxobjectdataptr}
 118
 119 \func{wxEXPLICIT}{wxObjectDataPtr<T>}{\param{T* }{ptr = NULL}}
 120
 121 Constructor. {\it ptr} is a pointer to the reference
 122 counted object to which this class points.
 123
 124 \func{}{wxObjectDataPtr<T>}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
 125
 126 This copy constructor increases the count of the reference
 127 counted object to which {\it tocopy} points and then this
 128 class will point to, as well.
 129
 130 \membersection{wxObjectDataPtr<T>::\destruct{wxObjectDataPtr<T>}}\label{wxobjectdataptrdtor}
 131
 132 \func{}{\destruct{wxObjectDataPtr<T>}}{\void}
 133
 134 Calls \helpref{DecRef}{wxobjectrefdatadecref} on the reference
 135 counted object to which this class points.
 136
 137 \membersection{wxObjectDataPtr<T>::operator->}\label{wxobjectdataptroperatorpointer}
 138
 139 \constfunc{T*}{operator->}{\void}
 140
 141 Gets a pointer to the reference counted object to which
 142 this class points. Same as \helpref{get}{wxobjectdataptrget}.
 143
 144 \membersection{wxObjectDataPtr<T>::operator=}\label{wxobjectdataptroperatorassign}
 145
 146 \func{wxObjectDataPtr<T>\& operator}{operator=}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
 147
 148 \func{wxObjectDataPtr<T>\& operator}{operator=}{\param{T* }{ptr}}
 149
 150 Assignment operators.
 151
 152 \membersection{wxObjectDataPtr<T>::get}\label{wxobjectdataptrget}
 153
 154 \constfunc{T*}{get}{\void}
 155
 156 Gets a pointer to the reference counted object to which
 157 this class points.
 158
 159 \membersection{wxObjectDataPtr<T>::reset}\label{wxobjectdataptrreset}
 160
 161 \func{void}{reset}{\param{T* }{ptr}}
 162
 163 Reset this class to {\it ptr} which points to a reference
 164 counted object.