wtf/RetainPtr.h

   1 // -*- mode: c++; c-basic-offset: 4 -*-
   2 /*
   3  *  This file is part of the KDE libraries
   4  *  Copyright (C) 2005, 2006 Apple Computer, Inc.
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Library General Public
   8  *  License as published by the Free Software Foundation; either
   9  *  version 2 of the License, or (at your option) any later version.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Library General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Library General Public License
  17  *  along with this library; see the file COPYING.LIB.  If not, write to
  18  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  *  Boston, MA 02110-1301, USA.
  20  *
  21  */
  22
  23 #ifndef RetainPtr_h
  24 #define RetainPtr_h
  25
  26 #include <algorithm>
  27 #include <CoreFoundation/CoreFoundation.h>
  28
  29 #ifdef __OBJC__
  30 #import <Foundation/Foundation.h>
  31 #endif
  32
  33 namespace WTF {
  34
  35     template <typename T> struct RemovePointer {
  36         typedef T type;
  37     };
  38
  39     template <typename T> struct RemovePointer<T*> {
  40         typedef T type;
  41     };
  42
  43     // Unlike most most of our smart pointers, RetainPtr can take either the pointer type or the pointed-to type,
  44     // so both RetainPtr<NSDictionary> and RetainPtr<CFDictionaryRef> will work.
  45
  46     enum AdoptCFTag { AdoptCF };
  47     enum AdoptNSTag { AdoptNS };
  48
  49 #ifdef __OBJC__
  50     inline void adoptNSReference(id ptr)
  51     {
  52         if (ptr) {
  53             CFRetain(ptr);
  54             [ptr release];
  55         }
  56     }
  57 #endif
  58
  59     template <typename T> class RetainPtr {
  60     public:
  61         typedef typename RemovePointer<T>::type ValueType;
  62         typedef ValueType* PtrType;
  63
  64         RetainPtr() : m_ptr(0) {}
  65         RetainPtr(PtrType ptr) : m_ptr(ptr) { if (ptr) CFRetain(ptr); }
  66
  67         RetainPtr(AdoptCFTag, PtrType ptr) : m_ptr(ptr) { }
  68         RetainPtr(AdoptNSTag, PtrType ptr) : m_ptr(ptr) { adoptNSReference(ptr); }
  69
  70         RetainPtr(const RetainPtr& o) : m_ptr(o.m_ptr) { if (PtrType ptr = m_ptr) CFRetain(ptr); }
  71
  72         ~RetainPtr() { if (PtrType ptr = m_ptr) CFRelease(ptr); }
  73
  74         template <typename U> RetainPtr(const RetainPtr<U>& o) : m_ptr(o.get()) { if (PtrType ptr = m_ptr) CFRetain(ptr); }
  75
  76         PtrType get() const { return m_ptr; }
  77
  78         PtrType releaseRef() { PtrType tmp = m_ptr; m_ptr = 0; return tmp; }
  79
  80         PtrType operator->() const { return m_ptr; }
  81
  82         bool operator!() const { return !m_ptr; }
  83
  84         // This conversion operator allows implicit conversion to bool but not to other integer types.
  85         typedef PtrType RetainPtr::*UnspecifiedBoolType;
  86         operator UnspecifiedBoolType() const { return m_ptr ? &RetainPtr::m_ptr : 0; }
  87
  88         RetainPtr& operator=(const RetainPtr&);
  89         template <typename U> RetainPtr& operator=(const RetainPtr<U>&);
  90         RetainPtr& operator=(PtrType);
  91         template <typename U> RetainPtr& operator=(U*);
  92
  93         void adoptCF(PtrType);
  94         void adoptNS(PtrType);
  95
  96         void swap(RetainPtr&);
  97
  98     private:
  99         PtrType m_ptr;
 100     };
 101
 102     template <typename T> inline RetainPtr<T>& RetainPtr<T>::operator=(const RetainPtr<T>& o)
 103     {
 104         PtrType optr = o.get();
 105         if (optr)
 106             CFRetain(optr);
 107         PtrType ptr = m_ptr;
 108         m_ptr = optr;
 109         if (ptr)
 110             CFRelease(ptr);
 111         return *this;
 112     }
 113
 114     template <typename T> template <typename U> inline RetainPtr<T>& RetainPtr<T>::operator=(const RetainPtr<U>& o)
 115     {
 116         PtrType optr = o.get();
 117         if (optr)
 118             CFRetain(optr);
 119         PtrType ptr = m_ptr;
 120         m_ptr = optr;
 121         if (ptr)
 122             CFRelease(ptr);
 123         return *this;
 124     }
 125
 126     template <typename T> inline RetainPtr<T>& RetainPtr<T>::operator=(PtrType optr)
 127     {
 128         if (optr)
 129             CFRetain(optr);
 130         PtrType ptr = m_ptr;
 131         m_ptr = optr;
 132         if (ptr)
 133             CFRelease(ptr);
 134         return *this;
 135     }
 136
 137     template <typename T> inline void RetainPtr<T>::adoptCF(PtrType optr)
 138     {
 139         PtrType ptr = m_ptr;
 140         m_ptr = optr;
 141         if (ptr)
 142             CFRelease(ptr);
 143     }
 144
 145     template <typename T> inline void RetainPtr<T>::adoptNS(PtrType optr)
 146     {
 147         adoptNSReference(optr);
 148
 149         PtrType ptr = m_ptr;
 150         m_ptr = optr;
 151         if (ptr)
 152             CFRelease(ptr);
 153     }
 154
 155     template <typename T> template <typename U> inline RetainPtr<T>& RetainPtr<T>::operator=(U* optr)
 156     {
 157         if (optr)
 158             CFRetain(optr);
 159         PtrType ptr = m_ptr;
 160         m_ptr = optr;
 161         if (ptr)
 162             CFRelease(ptr);
 163         return *this;
 164     }
 165
 166     template <class T> inline void RetainPtr<T>::swap(RetainPtr<T>& o)
 167     {
 168         std::swap(m_ptr, o.m_ptr);
 169     }
 170
 171     template <class T> inline void swap(RetainPtr<T>& a, RetainPtr<T>& b)
 172     {
 173         a.swap(b);
 174     }
 175
 176     template <typename T, typename U> inline bool operator==(const RetainPtr<T>& a, const RetainPtr<U>& b)
 177     {
 178         return a.get() == b.get();
 179     }
 180
 181     template <typename T, typename U> inline bool operator==(const RetainPtr<T>& a, U* b)
 182     {
 183         return a.get() == b;
 184     }
 185
 186     template <typename T, typename U> inline bool operator==(T* a, const RetainPtr<U>& b)
 187     {
 188         return a == b.get();
 189     }
 190
 191     template <typename T, typename U> inline bool operator!=(const RetainPtr<T>& a, const RetainPtr<U>& b)
 192     {
 193         return a.get() != b.get();
 194     }
 195
 196     template <typename T, typename U> inline bool operator!=(const RetainPtr<T>& a, U* b)
 197     {
 198         return a.get() != b;
 199     }
 200
 201     template <typename T, typename U> inline bool operator!=(T* a, const RetainPtr<U>& b)
 202     {
 203         return a != b.get();
 204     }
 205
 206 } // namespace WTF
 207
 208 using WTF::AdoptCF;
 209 using WTF::AdoptNS;
 210 using WTF::RetainPtr;
 211
 212 #endif // WTF_RetainPtr_h