1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef V8_SMART_POINTERS_H_
6 #define V8_SMART_POINTERS_H_
12 template<typename Deallocator, typename T>
13 class SmartPointerBase {
15 // Default constructor. Constructs an empty scoped pointer.
16 SmartPointerBase() : p_(NULL) {}
18 // Constructs a scoped pointer from a plain one.
19 explicit SmartPointerBase(T* ptr) : p_(ptr) {}
21 // Copy constructor removes the pointer from the original to avoid double
23 SmartPointerBase(const SmartPointerBase<Deallocator, T>& rhs)
25 const_cast<SmartPointerBase<Deallocator, T>&>(rhs).p_ = NULL;
28 T* operator->() const { return p_; }
30 T& operator*() const { return *p_; }
32 T* get() const { return p_; }
34 // You can use [n] to index as if it was a plain pointer.
35 T& operator[](size_t i) {
39 // You can use [n] to index as if it was a plain pointer.
40 const T& operator[](size_t i) const {
44 // We don't have implicit conversion to a T* since that hinders migration:
45 // You would not be able to change a method from returning a T* to
46 // returning an SmartArrayPointer<T> and then get errors wherever it is used.
49 // If you want to take out the plain pointer and don't want it automatically
50 // deleted then call Detach(). Afterwards, the smart pointer is empty
58 void Reset(T* new_value) {
59 DCHECK(p_ == NULL || p_ != new_value);
60 if (p_) Deallocator::Delete(p_);
64 // Assignment requires an empty (NULL) SmartArrayPointer as the receiver. Like
65 // the copy constructor it removes the pointer in the original to avoid
67 SmartPointerBase<Deallocator, T>& operator=(
68 const SmartPointerBase<Deallocator, T>& rhs) {
70 T* tmp = rhs.p_; // swap to handle self-assignment
71 const_cast<SmartPointerBase<Deallocator, T>&>(rhs).p_ = NULL;
76 bool is_empty() const { return p_ == NULL; }
79 // When the destructor of the scoped pointer is executed the plain pointer
80 // is deleted using DeleteArray. This implies that you must allocate with
82 ~SmartPointerBase() { if (p_) Deallocator::Delete(p_); }
88 // A 'scoped array pointer' that calls DeleteArray on its pointer when the
89 // destructor is called.
92 struct ArrayDeallocator {
93 static void Delete(T* array) {
100 class SmartArrayPointer: public SmartPointerBase<ArrayDeallocator<T>, T> {
102 SmartArrayPointer() { }
103 explicit SmartArrayPointer(T* ptr)
104 : SmartPointerBase<ArrayDeallocator<T>, T>(ptr) { }
105 SmartArrayPointer(const SmartArrayPointer<T>& rhs)
106 : SmartPointerBase<ArrayDeallocator<T>, T>(rhs) { }
111 struct ObjectDeallocator {
112 static void Delete(T* object) {
119 class SmartPointer: public SmartPointerBase<ObjectDeallocator<T>, T> {
122 explicit SmartPointer(T* ptr)
123 : SmartPointerBase<ObjectDeallocator<T>, T>(ptr) { }
124 SmartPointer(const SmartPointer<T>& rhs)
125 : SmartPointerBase<ObjectDeallocator<T>, T>(rhs) { }
128 } } // namespace v8::internal
130 #endif // V8_SMART_POINTERS_H_