1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 #ifndef GOOGLE_PROTOBUF_STUBS_SCOPED_PTR_H_ 32 #define GOOGLE_PROTOBUF_STUBS_SCOPED_PTR_H_ 33 34 #include <google/protobuf/stubs/port.h> 35 36 namespace google { 37 namespace protobuf { 38 39 // =================================================================== 40 // from google3/base/scoped_ptr.h 41 42 namespace internal { 43 44 // This is an implementation designed to match the anticipated future TR2 45 // implementation of the scoped_ptr class, and its closely-related brethren, 46 // scoped_array, scoped_ptr_malloc, and make_scoped_ptr. 47 48 template <class C> class scoped_ptr; 49 template <class C> class scoped_array; 50 51 // A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T> 52 // automatically deletes the pointer it holds (if any). 53 // That is, scoped_ptr<T> owns the T object that it points to. 54 // Like a T*, a scoped_ptr<T> may hold either NULL or a pointer to a T object. 55 // 56 // The size of a scoped_ptr is small: 57 // sizeof(scoped_ptr<C>) == sizeof(C*) 58 template <class C> 59 class scoped_ptr { 60 public: 61 62 // The element type 63 typedef C element_type; 64 65 // Constructor. Defaults to initializing with NULL. 66 // There is no way to create an uninitialized scoped_ptr. 67 // The input parameter must be allocated with new. ptr_(p)68 explicit scoped_ptr(C* p = NULL) : ptr_(p) { } 69 70 // Destructor. If there is a C object, delete it. 71 // We don't need to test ptr_ == NULL because C++ does that for us. ~scoped_ptr()72 ~scoped_ptr() { 73 enum { type_must_be_complete = sizeof(C) }; 74 delete ptr_; 75 } 76 77 // Reset. Deletes the current owned object, if any. 78 // Then takes ownership of a new object, if given. 79 // this->reset(this->get()) works. 80 void reset(C* p = NULL) { 81 if (p != ptr_) { 82 enum { type_must_be_complete = sizeof(C) }; 83 delete ptr_; 84 ptr_ = p; 85 } 86 } 87 88 // Accessors to get the owned object. 89 // operator* and operator-> will assert() if there is no current object. 90 C& operator*() const { 91 assert(ptr_ != NULL); 92 return *ptr_; 93 } 94 C* operator->() const { 95 assert(ptr_ != NULL); 96 return ptr_; 97 } get()98 C* get() const { return ptr_; } 99 100 // Comparison operators. 101 // These return whether two scoped_ptr refer to the same object, not just to 102 // two different but equal objects. 103 bool operator==(C* p) const { return ptr_ == p; } 104 bool operator!=(C* p) const { return ptr_ != p; } 105 106 // Swap two scoped pointers. swap(scoped_ptr & p2)107 void swap(scoped_ptr& p2) { 108 C* tmp = ptr_; 109 ptr_ = p2.ptr_; 110 p2.ptr_ = tmp; 111 } 112 113 // Release a pointer. 114 // The return value is the current pointer held by this object. 115 // If this object holds a NULL pointer, the return value is NULL. 116 // After this operation, this object will hold a NULL pointer, 117 // and will not own the object any more. release()118 C* release() { 119 C* retVal = ptr_; 120 ptr_ = NULL; 121 return retVal; 122 } 123 124 private: 125 C* ptr_; 126 127 // Forbid comparison of scoped_ptr types. If C2 != C, it totally doesn't 128 // make sense, and if C2 == C, it still doesn't make sense because you should 129 // never have the same object owned by two different scoped_ptrs. 130 template <class C2> bool operator==(scoped_ptr<C2> const& p2) const; 131 template <class C2> bool operator!=(scoped_ptr<C2> const& p2) const; 132 133 // Disallow evil constructors 134 scoped_ptr(const scoped_ptr&); 135 void operator=(const scoped_ptr&); 136 }; 137 138 // scoped_array<C> is like scoped_ptr<C>, except that the caller must allocate 139 // with new [] and the destructor deletes objects with delete []. 140 // 141 // As with scoped_ptr<C>, a scoped_array<C> either points to an object 142 // or is NULL. A scoped_array<C> owns the object that it points to. 143 // 144 // Size: sizeof(scoped_array<C>) == sizeof(C*) 145 template <class C> 146 class scoped_array { 147 public: 148 149 // The element type 150 typedef C element_type; 151 152 // Constructor. Defaults to initializing with NULL. 153 // There is no way to create an uninitialized scoped_array. 154 // The input parameter must be allocated with new []. array_(p)155 explicit scoped_array(C* p = NULL) : array_(p) { } 156 157 // Destructor. If there is a C object, delete it. 158 // We don't need to test ptr_ == NULL because C++ does that for us. ~scoped_array()159 ~scoped_array() { 160 enum { type_must_be_complete = sizeof(C) }; 161 delete[] array_; 162 } 163 164 // Reset. Deletes the current owned object, if any. 165 // Then takes ownership of a new object, if given. 166 // this->reset(this->get()) works. 167 void reset(C* p = NULL) { 168 if (p != array_) { 169 enum { type_must_be_complete = sizeof(C) }; 170 delete[] array_; 171 array_ = p; 172 } 173 } 174 175 // Get one element of the current object. 176 // Will assert() if there is no current object, or index i is negative. 177 C& operator[](std::ptrdiff_t i) const { 178 assert(i >= 0); 179 assert(array_ != NULL); 180 return array_[i]; 181 } 182 183 // Get a pointer to the zeroth element of the current object. 184 // If there is no current object, return NULL. get()185 C* get() const { 186 return array_; 187 } 188 189 // Comparison operators. 190 // These return whether two scoped_array refer to the same object, not just to 191 // two different but equal objects. 192 bool operator==(C* p) const { return array_ == p; } 193 bool operator!=(C* p) const { return array_ != p; } 194 195 // Swap two scoped arrays. swap(scoped_array & p2)196 void swap(scoped_array& p2) { 197 C* tmp = array_; 198 array_ = p2.array_; 199 p2.array_ = tmp; 200 } 201 202 // Release an array. 203 // The return value is the current pointer held by this object. 204 // If this object holds a NULL pointer, the return value is NULL. 205 // After this operation, this object will hold a NULL pointer, 206 // and will not own the object any more. release()207 C* release() { 208 C* retVal = array_; 209 array_ = NULL; 210 return retVal; 211 } 212 213 private: 214 C* array_; 215 216 // Forbid comparison of different scoped_array types. 217 template <class C2> bool operator==(scoped_array<C2> const& p2) const; 218 template <class C2> bool operator!=(scoped_array<C2> const& p2) const; 219 220 // Disallow evil constructors 221 scoped_array(const scoped_array&); 222 void operator=(const scoped_array&); 223 }; 224 225 } // namespace internal 226 227 // We made these internal so that they would show up as such in the docs, 228 // but we don't want to stick "internal::" in front of them everywhere. 229 using internal::scoped_ptr; 230 using internal::scoped_array; 231 232 233 } // namespace protobuf 234 } // namespace google 235 236 #endif // GOOGLE_PROTOBUF_STUBS_SCOPED_PTR_H_ 237