1 // Copyright 2008 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_SMART_POINTER_H_ 29 #define V8_SMART_POINTER_H_ 30 31 namespace v8 { 32 namespace internal { 33 34 35 // A 'scoped array pointer' that calls DeleteArray on its pointer when the 36 // destructor is called. 37 template<typename T> 38 class SmartPointer { 39 public: 40 41 // Default constructor. Construct an empty scoped pointer. 42 inline SmartPointer() : p(NULL) {} 43 44 45 // Construct a scoped pointer from a plain one. 46 explicit inline SmartPointer(T* pointer) : p(pointer) {} 47 48 49 // Copy constructor removes the pointer from the original to avoid double 50 // freeing. 51 inline SmartPointer(const SmartPointer<T>& rhs) : p(rhs.p) { 52 const_cast<SmartPointer<T>&>(rhs).p = NULL; 53 } 54 55 56 // When the destructor of the scoped pointer is executed the plain pointer 57 // is deleted using DeleteArray. This implies that you must allocate with 58 // NewArray. 59 inline ~SmartPointer() { if (p) DeleteArray(p); } 60 61 62 // You can get the underlying pointer out with the * operator. 63 inline T* operator*() { return p; } 64 65 66 // You can use [n] to index as if it was a plain pointer 67 inline T& operator[](size_t i) { 68 return p[i]; 69 } 70 71 // We don't have implicit conversion to a T* since that hinders migration: 72 // You would not be able to change a method from returning a T* to 73 // returning an SmartPointer<T> and then get errors wherever it is used. 74 75 76 // If you want to take out the plain pointer and don't want it automatically 77 // deleted then call Detach(). Afterwards, the smart pointer is empty 78 // (NULL). 79 inline T* Detach() { 80 T* temp = p; 81 p = NULL; 82 return temp; 83 } 84 85 86 // Assignment requires an empty (NULL) SmartPointer as the receiver. Like 87 // the copy constructor it removes the pointer in the original to avoid 88 // double freeing. 89 inline SmartPointer& operator=(const SmartPointer<T>& rhs) { 90 ASSERT(is_empty()); 91 T* tmp = rhs.p; // swap to handle self-assignment 92 const_cast<SmartPointer<T>&>(rhs).p = NULL; 93 p = tmp; 94 return *this; 95 } 96 97 98 inline bool is_empty() { 99 return p == NULL; 100 } 101 102 103 private: 104 T* p; 105 }; 106 107 } } // namespace v8::internal 108 109 #endif // V8_SMART_POINTER_H_ 110