PMDK C++ bindings  1.12-git53.g67ba2be4
This is the C++ bindings documentation for PMDK's libpmemobj.
v.hpp
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1 // SPDX-License-Identifier: BSD-3-Clause
2 /* Copyright 2018-2020, Intel Corporation */
3 
9 #ifndef LIBPMEMOBJ_CPP_V_HPP
10 #define LIBPMEMOBJ_CPP_V_HPP
11 
12 #include <memory>
13 #include <tuple>
14 
17 
18 namespace pmem
19 {
20 
21 namespace obj
22 {
23 
24 namespace experimental
25 {
26 
41 template <typename T>
42 class v {
43 public:
44  static_assert(std::is_default_constructible<T>::value,
45  "Type T must be default constructible");
46 
50  v() noexcept : vlt{0}
51  {
52  }
53 
57  ~v()
58  {
59  /* Destructor of val should NOT be called */
60  }
61 
65  v &
66  operator=(const T &rhs)
67  {
68  /* make sure object is initialized */
69  (void)get();
70 
71  val = rhs;
72 
73  return *this;
74  }
75 
79  v &
80  operator=(v &rhs)
81  {
82  return *this = rhs.get();
83  }
84 
90  template <typename Y,
91  typename = typename std::enable_if<
92  std::is_convertible<Y, T>::value>::type>
93  v &
95  {
96  return *this = rhs.get();
97  }
98 
108  template <typename... Args>
109  T &
110  get(Args &&... args) noexcept
111  {
112  auto arg_pack =
113  std::forward_as_tuple(std::forward<Args>(args)...);
114 
115  PMEMobjpool *pop = pmemobj_pool_by_ptr(this);
116  if (pop == NULL)
117  return this->val;
118 
119  T *value = static_cast<T *>(pmemobj_volatile(
120  pop, &this->vlt, &this->val, sizeof(T),
121  pmem::detail::c_style_construct<T, decltype(arg_pack),
122  Args...>,
123  static_cast<void *>(&arg_pack)));
124 
125  return *value;
126  }
127 
136  T &
138  {
139  return val;
140  }
141 
145  operator T &() noexcept
146  {
147  return this->get();
148  }
149 
153  void
154  swap(v &other)
155  {
156  std::swap(get(), other.get());
157  }
158 
159 private:
160  struct pmemvlt vlt;
161 
162  /*
163  * Normally C++ requires all class members to be constructed during
164  * enclosing type construction. Holding a value inside of a union allows
165  * to bypass this requirement. val is only constructed by call to get().
166  */
167  union {
168  T val;
169  };
170 };
171 
178 template <class T>
179 inline void
180 swap(v<T> &a, v<T> &b)
181 {
182  a.swap(b);
183 }
184 
185 } /* namespace experimental */
186 
187 } /* namespace obj */
188 
189 } /* namespace pmem */
190 
191 #endif /* LIBPMEMOBJ_CPP_V_HPP */
pmem::obj::experimental::v::swap
void swap(v &other)
Swaps two v objects of the same type.
Definition: v.hpp:154
pmem
Persistent memory namespace.
Definition: allocation_flag.hpp:15
pmem::obj::experimental::v::operator=
v & operator=(const T &rhs)
Assignment operator.
Definition: v.hpp:66
pmem::obj::experimental::v::unsafe_get
T & unsafe_get()
Retrieves reference to the object.
Definition: v.hpp:137
common.hpp
Commonly used functionality.
pmem::obj::experimental::swap
void swap(v< T > &a, v< T > &b)
Swaps two v objects of the same type.
Definition: v.hpp:180
pmem::obj::experimental::v::get
T & get(Args &&... args) noexcept
Retrieves reference to the object.
Definition: v.hpp:110
pmem::obj::experimental::v::operator=
v & operator=(v< Y > &rhs)
Converting assignment operator from a different v<>.
Definition: v.hpp:94
pmem::obj::experimental::swap
void swap(concurrent_map< Key, Value, Comp, Allocator > &lhs, concurrent_map< Key, Value, Comp, Allocator > &rhs)
Non-member swap.
Definition: concurrent_map.hpp:151
pmem::obj::experimental::v::~v
~v()
Destructor.
Definition: v.hpp:57
life.hpp
Functions for destroying arrays.
pmem::obj::experimental::v
Volatile residing on pmem class.
Definition: v.hpp:42
pmem::obj::experimental::v::v
v() noexcept
Defaulted constructor.
Definition: v.hpp:50
pmem::obj::experimental::v::operator=
v & operator=(v &rhs)
Assignment operator.
Definition: v.hpp:80