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      1 /*
      2  *  Copyright (C) 2006, 2010 Apple Inc. All rights reserved.
      3  *
      4  *  This library is free software; you can redistribute it and/or
      5  *  modify it under the terms of the GNU Library General Public
      6  *  License as published by the Free Software Foundation; either
      7  *  version 2 of the License, or (at your option) any later version.
      8  *
      9  *  This library is distributed in the hope that it will be useful,
     10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  *  Library General Public License for more details.
     13  *
     14  *  You should have received a copy of the GNU Library General Public License
     15  *  along with this library; see the file COPYING.LIB.  If not, write to
     16  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     17  *  Boston, MA 02110-1301, USA.
     18  *
     19  */
     20 
     21 #ifndef WTF_OwnArrayPtr_h
     22 #define WTF_OwnArrayPtr_h
     23 
     24 #include "wtf/Assertions.h"
     25 #include "wtf/Noncopyable.h"
     26 #include "wtf/NullPtr.h"
     27 #include "wtf/PassOwnArrayPtr.h"
     28 #include <algorithm>
     29 
     30 namespace WTF {
     31 
     32 template<typename T> class PassOwnArrayPtr;
     33 template<typename T> PassOwnArrayPtr<T> adoptArrayPtr(T*);
     34 
     35 template <typename T> class OwnArrayPtr {
     36 public:
     37     typedef T* PtrType;
     38 
     39     OwnArrayPtr() : m_ptr(0) { }
     40 
     41     // See comment in PassOwnArrayPtr.h for why this takes a const reference.
     42     template<typename U> OwnArrayPtr(const PassOwnArrayPtr<U>& o);
     43 
     44     // This copy constructor is used implicitly by gcc when it generates
     45     // transients for assigning a PassOwnArrayPtr<T> object to a stack-allocated
     46     // OwnArrayPtr<T> object. It should never be called explicitly and gcc
     47     // should optimize away the constructor when generating code.
     48     OwnArrayPtr(const OwnArrayPtr<T>&);
     49 
     50     ~OwnArrayPtr() { deleteOwnedArrayPtr(m_ptr); }
     51 
     52     PtrType get() const { return m_ptr; }
     53 
     54     void clear();
     55     PassOwnArrayPtr<T> release();
     56     PtrType leakPtr() WARN_UNUSED_RETURN;
     57 
     58     T& operator*() const { ASSERT(m_ptr); return *m_ptr; }
     59     PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
     60 
     61     T& operator[](std::ptrdiff_t i) const { ASSERT(m_ptr); ASSERT(i >= 0); return m_ptr[i]; }
     62 
     63     bool operator!() const { return !m_ptr; }
     64 
     65     // This conversion operator allows implicit conversion to bool but not to other integer types.
     66     typedef T* OwnArrayPtr::*UnspecifiedBoolType;
     67     operator UnspecifiedBoolType() const { return m_ptr ? &OwnArrayPtr::m_ptr : 0; }
     68 
     69     OwnArrayPtr& operator=(const PassOwnArrayPtr<T>&);
     70     OwnArrayPtr& operator=(std::nullptr_t) { clear(); return *this; }
     71     template<typename U> OwnArrayPtr& operator=(const PassOwnArrayPtr<U>&);
     72 
     73     void swap(OwnArrayPtr& o) { std::swap(m_ptr, o.m_ptr); }
     74 
     75 private:
     76     PtrType m_ptr;
     77 };
     78 
     79 template<typename T> template<typename U> inline OwnArrayPtr<T>::OwnArrayPtr(const PassOwnArrayPtr<U>& o)
     80     : m_ptr(o.leakPtr())
     81 {
     82 }
     83 
     84 template<typename T> inline void OwnArrayPtr<T>::clear()
     85 {
     86     PtrType ptr = m_ptr;
     87     m_ptr = 0;
     88     deleteOwnedArrayPtr(ptr);
     89 }
     90 
     91 template<typename T> inline PassOwnArrayPtr<T> OwnArrayPtr<T>::release()
     92 {
     93     PtrType ptr = m_ptr;
     94     m_ptr = 0;
     95     return adoptArrayPtr(ptr);
     96 }
     97 
     98 template<typename T> inline typename OwnArrayPtr<T>::PtrType OwnArrayPtr<T>::leakPtr()
     99 {
    100     PtrType ptr = m_ptr;
    101     m_ptr = 0;
    102     return ptr;
    103 }
    104 
    105 template<typename T> inline OwnArrayPtr<T>& OwnArrayPtr<T>::operator=(const PassOwnArrayPtr<T>& o)
    106 {
    107     PtrType ptr = m_ptr;
    108     m_ptr = o.leakPtr();
    109     ASSERT(!ptr || m_ptr != ptr);
    110     deleteOwnedArrayPtr(ptr);
    111     return *this;
    112 }
    113 
    114 template<typename T> template<typename U> inline OwnArrayPtr<T>& OwnArrayPtr<T>::operator=(const PassOwnArrayPtr<U>& o)
    115 {
    116     PtrType ptr = m_ptr;
    117     m_ptr = o.leakPtr();
    118     ASSERT(!ptr || m_ptr != ptr);
    119     deleteOwnedArrayPtr(ptr);
    120     return *this;
    121 }
    122 
    123 template <typename T> inline void swap(OwnArrayPtr<T>& a, OwnArrayPtr<T>& b)
    124 {
    125     a.swap(b);
    126 }
    127 
    128 template<typename T, typename U> inline bool operator==(const OwnArrayPtr<T>& a, U* b)
    129 {
    130     return a.get() == b;
    131 }
    132 
    133 template<typename T, typename U> inline bool operator==(T* a, const OwnArrayPtr<U>& b)
    134 {
    135     return a == b.get();
    136 }
    137 
    138 template<typename T, typename U> inline bool operator!=(const OwnArrayPtr<T>& a, U* b)
    139 {
    140     return a.get() != b;
    141 }
    142 
    143 template<typename T, typename U> inline bool operator!=(T* a, const OwnArrayPtr<U>& b)
    144 {
    145     return a != b.get();
    146 }
    147 
    148 template <typename T> inline T* getPtr(const OwnArrayPtr<T>& p)
    149 {
    150     return p.get();
    151 }
    152 
    153 } // namespace WTF
    154 
    155 using WTF::OwnArrayPtr;
    156 
    157 #endif // WTF_OwnArrayPtr_h
    158