1 // unique_ptr implementation -*- C++ -*-
2 
3 // Copyright (C) 2008, 2009, 2010, 2011 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 bits/unique_ptr.h
26  *  This is an internal header file, included by other library headers.
27  *  Do not attempt to use it directly. @headername{memory}
28  */
29 
30 #ifndef _UNIQUE_PTR_H
31 #define _UNIQUE_PTR_H 1
32 
33 #include <bits/c++config.h>
34 #include <debug/debug.h>
35 #include <type_traits>
36 #include <utility>
37 #include <tuple>
38 
39 namespace std _GLIBCXX_VISIBILITY(default)
40 {
41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 
43   /**
44    * @addtogroup pointer_abstractions
45    * @{
46    */
47 
48   /// Primary template, default_delete.
49   template<typename _Tp>
50     struct default_delete
51     {
52       constexpr default_delete() noexcept = default;
53 
54       template<typename _Up, typename = typename
55 	       std::enable_if<std::is_convertible<_Up*, _Tp*>::value>::type>
56         default_delete(const default_delete<_Up>&) noexcept { }
57 
58       void
59       operator()(_Tp* __ptr) const
60       {
61 	static_assert(sizeof(_Tp)>0,
62 		      "can't delete pointer to incomplete type");
63 	delete __ptr;
64       }
65     };
66 
67   // _GLIBCXX_RESOLVE_LIB_DEFECTS
68   // DR 740 - omit specialization for array objects with a compile time length
69   /// Specialization, default_delete.
70   template<typename _Tp>
71     struct default_delete<_Tp[]>
72     {
73       constexpr default_delete() noexcept = default;
74 
75       void
76       operator()(_Tp* __ptr) const
77       {
78 	static_assert(sizeof(_Tp)>0,
79 		      "can't delete pointer to incomplete type");
80 	delete [] __ptr;
81       }
82 
83       template<typename _Up> void operator()(_Up*) const = delete;
84     };
85 
86   /// 20.7.12.2 unique_ptr for single objects.
87   template <typename _Tp, typename _Dp = default_delete<_Tp> >
88     class unique_ptr
89     {
90       // use SFINAE to determine whether _Del::pointer exists
91       class _Pointer
92       {
93 	template<typename _Up>
94 	  static typename _Up::pointer __test(typename _Up::pointer*);
95 
96 	template<typename _Up>
97 	  static _Tp* __test(...);
98 
99 	typedef typename remove_reference<_Dp>::type _Del;
100 
101       public:
102 	typedef decltype( __test<_Del>(0)) type;
103       };
104 
105       typedef std::tuple<typename _Pointer::type, _Dp>  __tuple_type;
106       __tuple_type                                      _M_t;
107 
108     public:
109       typedef typename _Pointer::type   pointer;
110       typedef _Tp                       element_type;
111       typedef _Dp                       deleter_type;
112 
113       // Constructors.
114       constexpr unique_ptr() noexcept
115       : _M_t()
116       { static_assert(!std::is_pointer<deleter_type>::value,
117 		     "constructed with null function pointer deleter"); }
118 
119       explicit
120       unique_ptr(pointer __p) noexcept
121       : _M_t(__p, deleter_type())
122       { static_assert(!std::is_pointer<deleter_type>::value,
123 		     "constructed with null function pointer deleter"); }
124 
125       unique_ptr(pointer __p,
126 	  typename std::conditional<std::is_reference<deleter_type>::value,
127 	    deleter_type, const deleter_type&>::type __d) noexcept
128       : _M_t(__p, __d) { }
129 
130       unique_ptr(pointer __p,
131 	  typename std::remove_reference<deleter_type>::type&& __d) noexcept
132       : _M_t(std::move(__p), std::move(__d))
133       { static_assert(!std::is_reference<deleter_type>::value,
134 		      "rvalue deleter bound to reference"); }
135 
136       constexpr unique_ptr(nullptr_t) noexcept
137       : _M_t()
138       { static_assert(!std::is_pointer<deleter_type>::value,
139 		     "constructed with null function pointer deleter"); }
140 
141       // Move constructors.
142       unique_ptr(unique_ptr&& __u) noexcept
143       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
144 
145       template<typename _Up, typename _Ep, typename = typename
146 	std::enable_if
147 	  <std::is_convertible<typename unique_ptr<_Up, _Ep>::pointer,
148 			       pointer>::value
149 	   && !std::is_array<_Up>::value
150 	   && ((std::is_reference<_Dp>::value
151 		&& std::is_same<_Ep, _Dp>::value)
152 	       || (!std::is_reference<_Dp>::value
153 		   && std::is_convertible<_Ep, _Dp>::value))>
154 	     ::type>
155 	unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
156 	: _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
157 	{ }
158 
159 #if _GLIBCXX_USE_DEPRECATED
160       template<typename _Up, typename = typename
161 	std::enable_if<std::is_convertible<_Up*, _Tp*>::value
162 		       && std::is_same<_Dp,
163 				       default_delete<_Tp>>::value>::type>
164 	unique_ptr(auto_ptr<_Up>&& __u) noexcept
165 	: _M_t(__u.release(), deleter_type()) { }
166 #endif
167 
168       // Destructor.
169       ~unique_ptr() noexcept
170       {
171 	auto& __ptr = std::get<0>(_M_t);
172 	if (__ptr != nullptr)
173 	  get_deleter()(__ptr);
174 	__ptr = pointer();
175       }
176 
177       // Assignment.
178       unique_ptr&
179       operator=(unique_ptr&& __u) noexcept
180       {
181 	reset(__u.release());
182 	get_deleter() = std::forward<deleter_type>(__u.get_deleter());
183 	return *this;
184       }
185 
186       template<typename _Up, typename _Ep, typename = typename
187 	std::enable_if
188 	  <std::is_convertible<typename unique_ptr<_Up, _Ep>::pointer,
189 			       pointer>::value
190 	   && !std::is_array<_Up>::value>::type>
191 	unique_ptr&
192 	operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
193 	{
194 	  reset(__u.release());
195 	  get_deleter() = std::forward<_Ep>(__u.get_deleter());
196 	  return *this;
197 	}
198 
199       unique_ptr&
200       operator=(nullptr_t) noexcept
201       {
202 	reset();
203 	return *this;
204       }
205 
206       // Observers.
207       typename std::add_lvalue_reference<element_type>::type
208       operator*() const
209       {
210 	_GLIBCXX_DEBUG_ASSERT(get() != pointer());
211 	return *get();
212       }
213 
214       pointer
215       operator->() const noexcept
216       {
217 	_GLIBCXX_DEBUG_ASSERT(get() != pointer());
218 	return get();
219       }
220 
221       pointer
222       get() const noexcept
223       { return std::get<0>(_M_t); }
224 
225       deleter_type&
226       get_deleter() noexcept
227       { return std::get<1>(_M_t); }
228 
229       const deleter_type&
230       get_deleter() const noexcept
231       { return std::get<1>(_M_t); }
232 
233       explicit operator bool() const noexcept
234       { return get() == pointer() ? false : true; }
235 
236       // Modifiers.
237       pointer
238       release() noexcept
239       {
240 	pointer __p = get();
241 	std::get<0>(_M_t) = pointer();
242 	return __p;
243       }
244 
245       void
246       reset(pointer __p = pointer()) noexcept
247       {
248 	using std::swap;
249 	swap(std::get<0>(_M_t), __p);
250 	if (__p != pointer())
251 	  get_deleter()(__p);
252       }
253 
254       void
255       swap(unique_ptr& __u) noexcept
256       {
257 	using std::swap;
258 	swap(_M_t, __u._M_t);
259       }
260 
261       // Disable copy from lvalue.
262       unique_ptr(const unique_ptr&) = delete;
263       unique_ptr& operator=(const unique_ptr&) = delete;
264   };
265 
266   /// 20.7.12.3 unique_ptr for array objects with a runtime length
267   // [unique.ptr.runtime]
268   // _GLIBCXX_RESOLVE_LIB_DEFECTS
269   // DR 740 - omit specialization for array objects with a compile time length
270   template<typename _Tp, typename _Dp>
271     class unique_ptr<_Tp[], _Dp>
272     {
273       typedef std::tuple<_Tp*, _Dp>  	__tuple_type;
274       __tuple_type 			_M_t;
275 
276     public:
277       typedef _Tp*		 	pointer;
278       typedef _Tp		 	element_type;
279       typedef _Dp                       deleter_type;
280 
281       // Constructors.
282       constexpr unique_ptr() noexcept
283       : _M_t()
284       { static_assert(!std::is_pointer<deleter_type>::value,
285 		     "constructed with null function pointer deleter"); }
286 
287       explicit
288       unique_ptr(pointer __p) noexcept
289       : _M_t(__p, deleter_type())
290       { static_assert(!std::is_pointer<deleter_type>::value,
291 		     "constructed with null function pointer deleter"); }
292 
293       unique_ptr(pointer __p,
294 	  typename std::conditional<std::is_reference<deleter_type>::value,
295 	      deleter_type, const deleter_type&>::type __d) noexcept
296       : _M_t(__p, __d) { }
297 
298       unique_ptr(pointer __p, typename
299 		 std::remove_reference<deleter_type>::type && __d) noexcept
300       : _M_t(std::move(__p), std::move(__d))
301       { static_assert(!std::is_reference<deleter_type>::value,
302 		      "rvalue deleter bound to reference"); }
303 
304       constexpr unique_ptr(nullptr_t) noexcept
305       : _M_t()
306       { static_assert(!std::is_pointer<deleter_type>::value,
307 		     "constructed with null function pointer deleter"); }
308 
309       // Move constructors.
310       unique_ptr(unique_ptr&& __u) noexcept
311       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
312 
313       template<typename _Up, typename _Ep>
314 	unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
315 	: _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
316 	{ }
317 
318       // Destructor.
319       ~unique_ptr()
320       {
321 	auto& __ptr = std::get<0>(_M_t);
322 	if (__ptr != nullptr)
323 	  get_deleter()(__ptr);
324 	__ptr = pointer();
325       }
326 
327       // Assignment.
328       unique_ptr&
329       operator=(unique_ptr&& __u) noexcept
330       {
331 	reset(__u.release());
332 	get_deleter() = std::forward<deleter_type>(__u.get_deleter());
333 	return *this;
334       }
335 
336       template<typename _Up, typename _Ep>
337 	unique_ptr&
338 	operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
339 	{
340 	  reset(__u.release());
341 	  get_deleter() = std::forward<_Ep>(__u.get_deleter());
342 	  return *this;
343 	}
344 
345       unique_ptr&
346       operator=(nullptr_t) noexcept
347       {
348 	reset();
349 	return *this;
350       }
351 
352       // Observers.
353       typename std::add_lvalue_reference<element_type>::type
354       operator[](size_t __i) const
355       {
356 	_GLIBCXX_DEBUG_ASSERT(get() != pointer());
357 	return get()[__i];
358       }
359 
360       pointer
361       get() const noexcept
362       { return std::get<0>(_M_t); }
363 
364       deleter_type&
365       get_deleter() noexcept
366       { return std::get<1>(_M_t); }
367 
368       const deleter_type&
369       get_deleter() const noexcept
370       { return std::get<1>(_M_t); }
371 
372       explicit operator bool() const noexcept
373       { return get() == pointer() ? false : true; }
374 
375       // Modifiers.
376       pointer
377       release() noexcept
378       {
379 	pointer __p = get();
380 	std::get<0>(_M_t) = pointer();
381 	return __p;
382       }
383 
384       void
385       reset(pointer __p = pointer()) noexcept
386       {
387 	using std::swap;
388 	swap(std::get<0>(_M_t), __p);
389 	if (__p != nullptr)
390 	  get_deleter()(__p);
391       }
392 
393       void
394       reset(nullptr_t) noexcept
395       {
396 	pointer __p = get();
397 	std::get<0>(_M_t) = pointer();
398 	if (__p != nullptr)
399 	  get_deleter()(__p);
400       }
401 
402       // DR 821.
403       template<typename _Up>
404 	void reset(_Up) = delete;
405 
406       void
407       swap(unique_ptr& __u) noexcept
408       {
409 	using std::swap;
410 	swap(_M_t, __u._M_t);
411       }
412 
413       // Disable copy from lvalue.
414       unique_ptr(const unique_ptr&) = delete;
415       unique_ptr& operator=(const unique_ptr&) = delete;
416 
417       // Disable construction from convertible pointer types.
418       // (N2315 - 20.6.5.3.1)
419       template<typename _Up>
420 	unique_ptr(_Up*, typename
421 		   std::conditional<std::is_reference<deleter_type>::value,
422 		   deleter_type, const deleter_type&>::type,
423 		   typename std::enable_if<std::is_convertible<_Up*,
424 		   pointer>::value>::type* = 0) = delete;
425 
426       template<typename _Up>
427 	unique_ptr(_Up*, typename std::remove_reference<deleter_type>::type&&,
428 		   typename std::enable_if<std::is_convertible<_Up*,
429 		   pointer>::value>::type* = 0) = delete;
430 
431       template<typename _Up>
432 	explicit
433 	unique_ptr(_Up*, typename std::enable_if<std::is_convertible<_Up*,
434 		   pointer>::value>::type* = 0) = delete;
435     };
436 
437   template<typename _Tp, typename _Dp>
438     inline void
439     swap(unique_ptr<_Tp, _Dp>& __x,
440 	 unique_ptr<_Tp, _Dp>& __y) noexcept
441     { __x.swap(__y); }
442 
443   template<typename _Tp, typename _Dp,
444 	   typename _Up, typename _Ep>
445     inline bool
446     operator==(const unique_ptr<_Tp, _Dp>& __x,
447 	       const unique_ptr<_Up, _Ep>& __y)
448     { return __x.get() == __y.get(); }
449 
450   template<typename _Tp, typename _Dp>
451     inline bool
452     operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
453     { return !__x; }
454 
455   template<typename _Tp, typename _Dp>
456     inline bool
457     operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
458     { return !__x; }
459 
460   template<typename _Tp, typename _Dp,
461 	   typename _Up, typename _Ep>
462     inline bool
463     operator!=(const unique_ptr<_Tp, _Dp>& __x,
464 	       const unique_ptr<_Up, _Ep>& __y)
465     { return __x.get() != __y.get(); }
466 
467   template<typename _Tp, typename _Dp>
468     inline bool
469     operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
470     { return (bool)__x; }
471 
472   template<typename _Tp, typename _Dp>
473     inline bool
474     operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
475     { return (bool)__x; }
476 
477   template<typename _Tp, typename _Dp,
478 	   typename _Up, typename _Ep>
479     inline bool
480     operator<(const unique_ptr<_Tp, _Dp>& __x,
481 	      const unique_ptr<_Up, _Ep>& __y)
482     {
483       typedef typename
484 	std::common_type<typename unique_ptr<_Tp, _Dp>::pointer,
485 	                 typename unique_ptr<_Up, _Ep>::pointer>::type _CT;
486       return std::less<_CT>()(__x.get(), __y.get());
487     }
488 
489   template<typename _Tp, typename _Dp>
490     inline bool
491     operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
492     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
493 								 nullptr); }
494 
495   template<typename _Tp, typename _Dp>
496     inline bool
497     operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
498     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
499 								 __x.get()); }
500 
501   template<typename _Tp, typename _Dp,
502 	   typename _Up, typename _Ep>
503     inline bool
504     operator<=(const unique_ptr<_Tp, _Dp>& __x,
505 	       const unique_ptr<_Up, _Ep>& __y)
506     { return !(__y < __x); }
507 
508   template<typename _Tp, typename _Dp>
509     inline bool
510     operator<=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
511     { return !(nullptr < __x); }
512 
513   template<typename _Tp, typename _Dp>
514     inline bool
515     operator<=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
516     { return !(__x < nullptr); }
517 
518   template<typename _Tp, typename _Dp,
519 	   typename _Up, typename _Ep>
520     inline bool
521     operator>(const unique_ptr<_Tp, _Dp>& __x,
522 	      const unique_ptr<_Up, _Ep>& __y)
523     { return (__y < __x); }
524 
525   template<typename _Tp, typename _Dp>
526     inline bool
527     operator>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
528     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
529 								 __x.get()); }
530 
531   template<typename _Tp, typename _Dp>
532     inline bool
533     operator>(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
534     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
535 								 nullptr); }
536 
537   template<typename _Tp, typename _Dp,
538 	   typename _Up, typename _Ep>
539     inline bool
540     operator>=(const unique_ptr<_Tp, _Dp>& __x,
541 	       const unique_ptr<_Up, _Ep>& __y)
542     { return !(__x < __y); }
543 
544   template<typename _Tp, typename _Dp>
545     inline bool
546     operator>=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
547     { return !(__x < nullptr); }
548 
549   template<typename _Tp, typename _Dp>
550     inline bool
551     operator>=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
552     { return !(nullptr < __x); }
553 
554   /// std::hash specialization for unique_ptr.
555   template<typename _Tp, typename _Dp>
556     struct hash<unique_ptr<_Tp, _Dp>>
557     : public __hash_base<size_t, unique_ptr<_Tp, _Dp>>
558     {
559       size_t
560       operator()(const unique_ptr<_Tp, _Dp>& __u) const noexcept
561       {
562 	typedef unique_ptr<_Tp, _Dp> _UP;
563 	return std::hash<typename _UP::pointer>()(__u.get());
564       }
565     };
566 
567   // @} group pointer_abstractions
568 
569 _GLIBCXX_END_NAMESPACE_VERSION
570 } // namespace
571 
572 #endif /* _UNIQUE_PTR_H */
573