libstdc++
scoped_allocator
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1 // <scoped_allocator> -*- C++ -*-
2 
3 // Copyright (C) 2011-2020 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file include/scoped_allocator
26  * This is a Standard C++ Library header.
27  * @ingroup allocators
28  */
29 
30 #ifndef _SCOPED_ALLOCATOR
31 #define _SCOPED_ALLOCATOR 1
32 
33 #pragma GCC system_header
34 
35 #if __cplusplus < 201103L
36 # include <bits/c++0x_warning.h>
37 #else
38 
39 #include <memory>
40 #include <utility>
41 #include <tuple>
42 #include <bits/alloc_traits.h>
43 
44 namespace std _GLIBCXX_VISIBILITY(default)
45 {
46 _GLIBCXX_BEGIN_NAMESPACE_VERSION
47 
48  /**
49  * @addtogroup allocators
50  * @{
51  */
52 
53  /// @cond undocumented
54 
55  template<typename _Alloc>
56  using __outer_allocator_t
57  = decltype(std::declval<_Alloc>().outer_allocator());
58 
59  template<typename _Alloc, typename = void>
60  struct __outermost_type
61  {
62  using type = _Alloc;
63  static type& _S_outermost(_Alloc& __a) { return __a; }
64  };
65 
66  template<typename _Alloc>
67  struct __outermost_type<_Alloc, __void_t<__outer_allocator_t<_Alloc>>>
68  : __outermost_type<
69  typename remove_reference<__outer_allocator_t<_Alloc>>::type
70  >
71  {
72  using __base = __outermost_type<
73  typename remove_reference<__outer_allocator_t<_Alloc>>::type
74  >;
75 
76  static typename __base::type&
77  _S_outermost(_Alloc& __a)
78  { return __base::_S_outermost(__a.outer_allocator()); }
79  };
80 
81  /// Implementation of the OUTERMOST pseudofunction
82  template<typename _Alloc>
83  inline typename __outermost_type<_Alloc>::type&
84  __outermost(_Alloc& __a)
85  { return __outermost_type<_Alloc>::_S_outermost(__a); }
86 
87  template<typename _OuterAlloc, typename... _InnerAllocs>
88  class scoped_allocator_adaptor;
89 
90  template<typename...>
91  struct __inner_type_impl;
92 
93  template<typename _Outer>
94  struct __inner_type_impl<_Outer>
95  {
96  typedef scoped_allocator_adaptor<_Outer> __type;
97 
98  __inner_type_impl() = default;
99  __inner_type_impl(const __inner_type_impl&) = default;
100  __inner_type_impl(__inner_type_impl&&) = default;
101  __inner_type_impl& operator=(const __inner_type_impl&) = default;
102  __inner_type_impl& operator=(__inner_type_impl&&) = default;
103 
104  template<typename _Alloc>
105  __inner_type_impl(const __inner_type_impl<_Alloc>& __other)
106  { }
107 
108  template<typename _Alloc>
109  __inner_type_impl(__inner_type_impl<_Alloc>&& __other)
110  { }
111 
112  __type&
113  _M_get(__type* __p) noexcept { return *__p; }
114 
115  const __type&
116  _M_get(const __type* __p) const noexcept { return *__p; }
117 
118  tuple<>
119  _M_tie() const noexcept { return tuple<>(); }
120 
121  bool
122  operator==(const __inner_type_impl&) const noexcept
123  { return true; }
124  };
125 
126  template<typename _Outer, typename _InnerHead, typename... _InnerTail>
127  struct __inner_type_impl<_Outer, _InnerHead, _InnerTail...>
128  {
129  typedef scoped_allocator_adaptor<_InnerHead, _InnerTail...> __type;
130 
131  __inner_type_impl() = default;
132  __inner_type_impl(const __inner_type_impl&) = default;
133  __inner_type_impl(__inner_type_impl&&) = default;
134  __inner_type_impl& operator=(const __inner_type_impl&) = default;
135  __inner_type_impl& operator=(__inner_type_impl&&) = default;
136 
137  template<typename... _Allocs>
138  __inner_type_impl(const __inner_type_impl<_Allocs...>& __other)
139  : _M_inner(__other._M_inner) { }
140 
141  template<typename... _Allocs>
142  __inner_type_impl(__inner_type_impl<_Allocs...>&& __other)
143  : _M_inner(std::move(__other._M_inner)) { }
144 
145  template<typename... _Args>
146  explicit
147  __inner_type_impl(_Args&&... __args)
148  : _M_inner(std::forward<_Args>(__args)...) { }
149 
150  __type&
151  _M_get(void*) noexcept { return _M_inner; }
152 
153  const __type&
154  _M_get(const void*) const noexcept { return _M_inner; }
155 
156  tuple<const _InnerHead&, const _InnerTail&...>
157  _M_tie() const noexcept
158  { return _M_inner._M_tie(); }
159 
160  bool
161  operator==(const __inner_type_impl& __other) const noexcept
162  { return _M_inner == __other._M_inner; }
163 
164  private:
165  template<typename...> friend class __inner_type_impl;
166  template<typename, typename...> friend class scoped_allocator_adaptor;
167 
168  __type _M_inner;
169  };
170 
171  /// @endcond
172 
173  /// An adaptor to recursively pass an allocator to the objects it constructs
174  template<typename _OuterAlloc, typename... _InnerAllocs>
175  class scoped_allocator_adaptor
176  : public _OuterAlloc
177  {
178  typedef allocator_traits<_OuterAlloc> __traits;
179 
180  typedef __inner_type_impl<_OuterAlloc, _InnerAllocs...> __inner_type;
181  __inner_type _M_inner;
182 
183  template<typename _Outer, typename... _Inner>
184  friend class scoped_allocator_adaptor;
185 
186  template<typename...>
187  friend class __inner_type_impl;
188 
189  tuple<const _OuterAlloc&, const _InnerAllocs&...>
190  _M_tie() const noexcept
191  { return std::tuple_cat(std::tie(outer_allocator()), _M_inner._M_tie()); }
192 
193  template<typename _Alloc>
194  using __outermost_alloc_traits
195  = allocator_traits<typename __outermost_type<_Alloc>::type>;
196 
197 #if __cplusplus <= 201703
198  template<typename _Tp, typename... _Args>
199  void
200  _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args)
201  {
202  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
203  _O_traits::construct(__outermost(*this), __p,
204  std::forward<_Args>(__args)...);
205  }
206 
207  typedef __uses_alloc1<typename __inner_type::__type> __uses_alloc1_;
208  typedef __uses_alloc2<typename __inner_type::__type> __uses_alloc2_;
209 
210  template<typename _Tp, typename... _Args>
211  void
212  _M_construct(__uses_alloc1_, _Tp* __p, _Args&&... __args)
213  {
214  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
215  _O_traits::construct(__outermost(*this), __p,
216  allocator_arg, inner_allocator(),
217  std::forward<_Args>(__args)...);
218  }
219 
220  template<typename _Tp, typename... _Args>
221  void
222  _M_construct(__uses_alloc2_, _Tp* __p, _Args&&... __args)
223  {
224  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
225  _O_traits::construct(__outermost(*this), __p,
226  std::forward<_Args>(__args)...,
227  inner_allocator());
228  }
229 #endif // C++17
230 
231  template<typename _Alloc>
232  static _Alloc
233  _S_select_on_copy(const _Alloc& __a)
234  {
235  typedef allocator_traits<_Alloc> __a_traits;
236  return __a_traits::select_on_container_copy_construction(__a);
237  }
238 
239  template<std::size_t... _Indices>
240  scoped_allocator_adaptor(tuple<const _OuterAlloc&,
241  const _InnerAllocs&...> __refs,
242  _Index_tuple<_Indices...>)
243  : _OuterAlloc(_S_select_on_copy(std::get<0>(__refs))),
244  _M_inner(_S_select_on_copy(std::get<_Indices+1>(__refs))...)
245  { }
246 
247  // Used to constrain constructors to disallow invalid conversions.
248  template<typename _Alloc>
249  using _Constructible = typename enable_if<
250  is_constructible<_OuterAlloc, _Alloc>::value
251  >::type;
252 
253  // _GLIBCXX_RESOLVE_LIB_DEFECTS
254  // 2975. Missing case for pair construction in scoped [...] allocators
255  template<typename _Tp>
256  struct __not_pair { using type = void; };
257 
258  template<typename _Tp, typename _Up>
259  struct __not_pair<pair<_Tp, _Up>> { };
260 
261  public:
262  typedef _OuterAlloc outer_allocator_type;
263  typedef typename __inner_type::__type inner_allocator_type;
264 
265  typedef typename __traits::value_type value_type;
266  typedef typename __traits::size_type size_type;
267  typedef typename __traits::difference_type difference_type;
268  typedef typename __traits::pointer pointer;
269  typedef typename __traits::const_pointer const_pointer;
270  typedef typename __traits::void_pointer void_pointer;
271  typedef typename __traits::const_void_pointer const_void_pointer;
272 
273  typedef typename __or_<
274  typename __traits::propagate_on_container_copy_assignment,
275  typename allocator_traits<_InnerAllocs>::
276  propagate_on_container_copy_assignment...>::type
277  propagate_on_container_copy_assignment;
278 
279  typedef typename __or_<
280  typename __traits::propagate_on_container_move_assignment,
281  typename allocator_traits<_InnerAllocs>::
282  propagate_on_container_move_assignment...>::type
283  propagate_on_container_move_assignment;
284 
285  typedef typename __or_<
286  typename __traits::propagate_on_container_swap,
287  typename allocator_traits<_InnerAllocs>::
288  propagate_on_container_swap...>::type
289  propagate_on_container_swap;
290 
291  typedef typename __and_<
292  typename __traits::is_always_equal,
293  typename allocator_traits<_InnerAllocs>::is_always_equal...>::type
294  is_always_equal;
295 
296  template <class _Tp>
297  struct rebind
298  {
299  typedef scoped_allocator_adaptor<
300  typename __traits::template rebind_alloc<_Tp>,
301  _InnerAllocs...> other;
302  };
303 
304  scoped_allocator_adaptor() : _OuterAlloc(), _M_inner() { }
305 
306  template<typename _Outer2, typename = _Constructible<_Outer2>>
307  scoped_allocator_adaptor(_Outer2&& __outer,
308  const _InnerAllocs&... __inner)
309  : _OuterAlloc(std::forward<_Outer2>(__outer)),
310  _M_inner(__inner...)
311  { }
312 
313  scoped_allocator_adaptor(const scoped_allocator_adaptor& __other)
314  : _OuterAlloc(__other.outer_allocator()),
315  _M_inner(__other._M_inner)
316  { }
317 
318  scoped_allocator_adaptor(scoped_allocator_adaptor&& __other)
319  : _OuterAlloc(std::move(__other.outer_allocator())),
320  _M_inner(std::move(__other._M_inner))
321  { }
322 
323  template<typename _Outer2, typename = _Constructible<const _Outer2&>>
324  scoped_allocator_adaptor(
325  const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other)
326  : _OuterAlloc(__other.outer_allocator()),
327  _M_inner(__other._M_inner)
328  { }
329 
330  template<typename _Outer2, typename = _Constructible<_Outer2>>
331  scoped_allocator_adaptor(
332  scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other)
333  : _OuterAlloc(std::move(__other.outer_allocator())),
334  _M_inner(std::move(__other._M_inner))
335  { }
336 
337  scoped_allocator_adaptor&
338  operator=(const scoped_allocator_adaptor&) = default;
339 
340  scoped_allocator_adaptor&
341  operator=(scoped_allocator_adaptor&&) = default;
342 
343  inner_allocator_type& inner_allocator() noexcept
344  { return _M_inner._M_get(this); }
345 
346  const inner_allocator_type& inner_allocator() const noexcept
347  { return _M_inner._M_get(this); }
348 
349  outer_allocator_type& outer_allocator() noexcept
350  { return static_cast<_OuterAlloc&>(*this); }
351 
352  const outer_allocator_type& outer_allocator() const noexcept
353  { return static_cast<const _OuterAlloc&>(*this); }
354 
355  _GLIBCXX_NODISCARD pointer allocate(size_type __n)
356  { return __traits::allocate(outer_allocator(), __n); }
357 
358  _GLIBCXX_NODISCARD pointer allocate(size_type __n, const_void_pointer __hint)
359  { return __traits::allocate(outer_allocator(), __n, __hint); }
360 
361  void deallocate(pointer __p, size_type __n)
362  { return __traits::deallocate(outer_allocator(), __p, __n); }
363 
364  size_type max_size() const
365  { return __traits::max_size(outer_allocator()); }
366 
367 #if __cplusplus <= 201703
368  template<typename _Tp, typename... _Args>
369  typename __not_pair<_Tp>::type
370  construct(_Tp* __p, _Args&&... __args)
371  {
372  auto& __inner = inner_allocator();
373  auto __use_tag
374  = std::__use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
375  _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
376  }
377 
378  template<typename _T1, typename _T2, typename... _Args1,
379  typename... _Args2>
380  void
381  construct(pair<_T1, _T2>* __p, piecewise_construct_t,
382  tuple<_Args1...> __x, tuple<_Args2...> __y)
383  {
384  // _GLIBCXX_RESOLVE_LIB_DEFECTS
385  // 2203. wrong argument types for piecewise construction
386  auto& __inner = inner_allocator();
387  auto __x_use_tag
388  = std::__use_alloc<_T1, inner_allocator_type, _Args1...>(__inner);
389  auto __y_use_tag
390  = std::__use_alloc<_T2, inner_allocator_type, _Args2...>(__inner);
391  typename _Build_index_tuple<sizeof...(_Args1)>::__type __x_indices;
392  typename _Build_index_tuple<sizeof...(_Args2)>::__type __y_indices;
393  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
394  _O_traits::construct(__outermost(*this), __p, piecewise_construct,
395  _M_construct_p(__x_use_tag, __x_indices, __x),
396  _M_construct_p(__y_use_tag, __y_indices, __y));
397  }
398 
399  template<typename _T1, typename _T2>
400  void
401  construct(pair<_T1, _T2>* __p)
402  { construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
403 
404  template<typename _T1, typename _T2, typename _Up, typename _Vp>
405  void
406  construct(pair<_T1, _T2>* __p, _Up&& __u, _Vp&& __v)
407  {
408  construct(__p, piecewise_construct,
409  std::forward_as_tuple(std::forward<_Up>(__u)),
410  std::forward_as_tuple(std::forward<_Vp>(__v)));
411  }
412 
413  template<typename _T1, typename _T2, typename _Up, typename _Vp>
414  void
415  construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x)
416  {
417  construct(__p, piecewise_construct,
418  std::forward_as_tuple(__x.first),
419  std::forward_as_tuple(__x.second));
420  }
421 
422  template<typename _T1, typename _T2, typename _Up, typename _Vp>
423  void
424  construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x)
425  {
426  construct(__p, piecewise_construct,
427  std::forward_as_tuple(std::forward<_Up>(__x.first)),
428  std::forward_as_tuple(std::forward<_Vp>(__x.second)));
429  }
430 #else // C++2a
431  template<typename _Tp, typename... _Args>
432  __attribute__((__nonnull__))
433  void
434  construct(_Tp* __p, _Args&&... __args)
435  {
436  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
437  std::apply([__p, this](auto&&... __newargs) {
438  _O_traits::construct(__outermost(*this), __p,
439  std::forward<decltype(__newargs)>(__newargs)...);
440  },
441  uses_allocator_construction_args<_Tp>(inner_allocator(),
442  std::forward<_Args>(__args)...));
443  }
444 #endif // C++2a
445 
446  template<typename _Tp>
447  void destroy(_Tp* __p)
448  {
449  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
450  _O_traits::destroy(__outermost(*this), __p);
451  }
452 
453  scoped_allocator_adaptor
454  select_on_container_copy_construction() const
455  {
456  typedef typename _Build_index_tuple<sizeof...(_InnerAllocs)>::__type
457  _Indices;
458  return scoped_allocator_adaptor(_M_tie(), _Indices());
459  }
460 
461  template <typename _OutA1, typename _OutA2, typename... _InA>
462  friend bool
463  operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
464  const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept;
465 
466  private:
467 #if __cplusplus <= 201703L
468  template<typename _Ind, typename... _Args>
469  tuple<_Args&&...>
470  _M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t)
471  { return std::move(__t); }
472 
473  template<size_t... _Ind, typename... _Args>
474  tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>
475  _M_construct_p(__uses_alloc1_, _Index_tuple<_Ind...>,
476  tuple<_Args...>& __t)
477  {
478  return { allocator_arg, inner_allocator(),
479  std::get<_Ind>(std::move(__t))...
480  };
481  }
482 
483  template<size_t... _Ind, typename... _Args>
484  tuple<_Args&&..., inner_allocator_type&>
485  _M_construct_p(__uses_alloc2_, _Index_tuple<_Ind...>,
486  tuple<_Args...>& __t)
487  {
488  return { std::get<_Ind>(std::move(__t))..., inner_allocator() };
489  }
490 #endif // C++17
491  };
492 
493  /// @related std::scoped_allocator_adaptor
494  template <typename _OutA1, typename _OutA2, typename... _InA>
495  inline bool
496  operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
497  const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
498  {
499  return __a.outer_allocator() == __b.outer_allocator()
500  && __a._M_inner == __b._M_inner;
501  }
502 
503 #if __cpp_impl_three_way_comparison < 201907L
504  /// @related std::scoped_allocator_adaptor
505  template <typename _OutA1, typename _OutA2, typename... _InA>
506  inline bool
507  operator!=(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
508  const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
509  { return !(__a == __b); }
510 #endif
511 
512  /// @}
513 
514 _GLIBCXX_END_NAMESPACE_VERSION
515 } // namespace
516 
517 #endif // C++11
518 
519 #endif // _SCOPED_ALLOCATOR