| 1 | ///////////////////////////////////////////////////////////////////////////// |
| 2 | // Name: wx/ptr_shrd.h |
| 3 | // Purpose: Shared pointer based on the counted_ptr<> template, which |
| 4 | // is in the public domain |
| 5 | // Author: Robert Roebling, Yonat Sharon |
| 6 | // RCS-ID: $Id: object.h 47254 2007-07-09 10:09:52Z VS $ |
| 7 | // Copyright: Robert Roebling |
| 8 | // Licence: wxWindows licence |
| 9 | ///////////////////////////////////////////////////////////////////////////// |
| 10 | |
| 11 | #ifndef _WX_SHARED_PTRH__ |
| 12 | #define _WX_SHARED_PTRH__ |
| 13 | |
| 14 | #include "wx/defs.h" |
| 15 | #include "wx/atomic.h" |
| 16 | |
| 17 | // ---------------------------------------------------------------------------- |
| 18 | // wxSharedPtr: A smart pointer with non-intrusive reference counting. |
| 19 | // ---------------------------------------------------------------------------- |
| 20 | |
| 21 | template <class T> |
| 22 | class wxSharedPtr |
| 23 | { |
| 24 | public: |
| 25 | typedef T element_type; |
| 26 | |
| 27 | wxEXPLICIT wxSharedPtr( T* ptr = NULL ) |
| 28 | : m_ref(NULL) |
| 29 | { |
| 30 | if (ptr) |
| 31 | m_ref = new reftype(ptr); |
| 32 | } |
| 33 | |
| 34 | ~wxSharedPtr() { Release(); } |
| 35 | wxSharedPtr(const wxSharedPtr& tocopy) { Acquire(tocopy.m_ref); } |
| 36 | |
| 37 | wxSharedPtr& operator=( const wxSharedPtr& tocopy ) |
| 38 | { |
| 39 | if (this != &tocopy) |
| 40 | { |
| 41 | Release(); |
| 42 | Acquire(tocopy.m_ref); |
| 43 | } |
| 44 | return *this; |
| 45 | } |
| 46 | |
| 47 | wxSharedPtr& operator=( T* ptr ) |
| 48 | { |
| 49 | if (get() != ptr) |
| 50 | { |
| 51 | Release(); |
| 52 | if (ptr) |
| 53 | m_ref = new reftype(ptr); |
| 54 | } |
| 55 | return *this; |
| 56 | } |
| 57 | |
| 58 | // test for pointer validity: defining conversion to unspecified_bool_type |
| 59 | // and not more obvious bool to avoid implicit conversions to integer types |
| 60 | typedef T *(wxSharedPtr<T>::*unspecified_bool_type)() const; |
| 61 | operator unspecified_bool_type() const |
| 62 | { |
| 63 | if (m_ref && m_ref->m_ptr) |
| 64 | return &wxSharedPtr<T>::get; |
| 65 | else |
| 66 | return NULL; |
| 67 | } |
| 68 | |
| 69 | T& operator*() const |
| 70 | { |
| 71 | wxASSERT(m_ref != NULL); |
| 72 | wxASSERT(m_ref->m_ptr != NULL); |
| 73 | return *(m_ref->m_ptr); |
| 74 | } |
| 75 | |
| 76 | T* operator->() const |
| 77 | { |
| 78 | wxASSERT(m_ref != NULL); |
| 79 | wxASSERT(m_ref->m_ptr != NULL); |
| 80 | return m_ref->m_ptr; |
| 81 | } |
| 82 | |
| 83 | T* get() const |
| 84 | { |
| 85 | return m_ref ? m_ref->m_ptr : NULL; |
| 86 | } |
| 87 | |
| 88 | void reset( T* ptr = NULL ) |
| 89 | { |
| 90 | Release(); |
| 91 | if (ptr) |
| 92 | m_ref = new reftype(ptr); |
| 93 | } |
| 94 | |
| 95 | bool unique() const { return (m_ref ? m_ref->m_count == 1 : true); } |
| 96 | long use_count() const { return (m_ref ? (long)m_ref->m_count : 0); } |
| 97 | |
| 98 | private: |
| 99 | |
| 100 | struct reftype |
| 101 | { |
| 102 | reftype( T* ptr = NULL, unsigned count = 1 ) : m_ptr(ptr), m_count(count) {} |
| 103 | T* m_ptr; |
| 104 | wxAtomicInt m_count; |
| 105 | }* m_ref; |
| 106 | |
| 107 | void Acquire(reftype* ref) |
| 108 | { |
| 109 | m_ref = ref; |
| 110 | if (ref) |
| 111 | wxAtomicInc( ref->m_count ); |
| 112 | } |
| 113 | |
| 114 | void Release() |
| 115 | { |
| 116 | if (m_ref) |
| 117 | { |
| 118 | wxAtomicDec( m_ref->m_count ); |
| 119 | if (m_ref->m_count == 0) |
| 120 | { |
| 121 | delete m_ref->m_ptr; |
| 122 | delete m_ref; |
| 123 | } |
| 124 | m_ref = NULL; |
| 125 | } |
| 126 | } |
| 127 | }; |
| 128 | |
| 129 | template <class T, class U> |
| 130 | bool operator == (wxSharedPtr<T> const &a, wxSharedPtr<U> const &b ) |
| 131 | { |
| 132 | return a.get() == b.get(); |
| 133 | } |
| 134 | |
| 135 | template <class T, class U> |
| 136 | bool operator != (wxSharedPtr<T> const &a, wxSharedPtr<U> const &b ) |
| 137 | { |
| 138 | return a.get() != b.get(); |
| 139 | } |
| 140 | |
| 141 | |
| 142 | |
| 143 | #endif // _WX_SHARED_PTRH__ |