include/wx/cocoa/ObjcRef.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/cocoa/ObjcRef.h
   3 // Purpose:     wxObjcAutoRef template class
   4 // Author:      David Elliott
   5 // Modified by:
   6 // Created:     2004/03/28
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2004 David Elliott <dfe@cox.net>
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 /*
  13 wxObjcAutoRefFromAlloc: construct a reference to an object that was
  14 [NSObject -alloc]'ed and thus does not need a retain
  15 wxObjcAutoRef: construct a reference to an object that was
  16 either autoreleased or is retained by something else.
  17 */
  18
  19 struct objc_object;
  20
  21 // We must do any calls to Objective-C from an Objective-C++ source file
  22 class wxObjcAutoRefBase
  23 {
  24 protected:
  25     static struct objc_object* ObjcRetain(struct objc_object*);
  26     static struct objc_object* ObjcRelease(struct objc_object*);
  27 };
  28
  29 // T should be a pointer like NSObject*
  30
  31 template <class T>
  32 class wxObjcAutoRefFromAlloc: wxObjcAutoRefBase
  33 {
  34 public:
  35     wxObjcAutoRefFromAlloc(T p = 0)
  36     :   m_ptr(p)
  37     // NOTE: this is from alloc.  Do NOT retain
  38     {}
  39     wxObjcAutoRefFromAlloc(const wxObjcAutoRefFromAlloc& otherRef)
  40     :   m_ptr(otherRef.m_ptr)
  41     {   ObjcRetain(m_ptr); }
  42     ~wxObjcAutoRefFromAlloc()
  43     {   ObjcRelease(m_ptr); }
  44     wxObjcAutoRefFromAlloc& operator=(const wxObjcAutoRefFromAlloc& otherRef)
  45     {   ObjcRetain(otherRef.m_ptr);
  46         ObjcRelease(m_ptr);
  47         m_ptr = otherRef.m_ptr;
  48         return *this;
  49     }
  50     operator T() const
  51     {   return m_ptr; }
  52     T operator->() const
  53     {   return m_ptr; }
  54 protected:
  55     T m_ptr;
  56 };
  57
  58 // The only thing wxObjcAutoRef has to do is retain an initial object
  59 template <class T>
  60 class wxObjcAutoRef: public wxObjcAutoRefFromAlloc<T>
  61 {
  62 public:
  63     wxObjcAutoRef(T p = 0)
  64     :   wxObjcAutoRefFromAlloc<T>(p)
  65     {   ObjcRetain(m_ptr); }
  66     ~wxObjcAutoRef() {}
  67     wxObjcAutoRef(const wxObjcAutoRef& otherRef)
  68     :   wxObjcAutoRefFromAlloc<T>(otherRef)
  69     {}
  70     wxObjcAutoRef(const wxObjcAutoRefFromAlloc<T>& otherRef)
  71     :   wxObjcAutoRefFromAlloc<T>(otherRef)
  72     {}
  73     wxObjcAutoRef& operator=(const wxObjcAutoRef& otherRef)
  74     {   return wxObjcAutoRefFromAlloc<T>::operator=(otherRef); }
  75 };
  76