11.2.0/bits/unique_lock.h

// std::unique_lock implementation -*- C++ -*-

// Copyright (C) 2008-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file bits/unique_lock.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{mutex}
 */

#ifndef _GLIBCXX_UNIQUE_LOCK_H
#define _GLIBCXX_UNIQUE_LOCK_H 1

#pragma GCC system_header

#if __cplusplus < 201103L
# include <bits/c++0x_warning.h>
#else

#include <chrono>
#include <bits/move.h> // for std::swap
#include <bits/std_mutex.h> // for std::defer_lock_t

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /** @brief A movable scoped lock type.
   *
   * A unique_lock controls mutex ownership within a scope. Ownership of the
   * mutex can be delayed until after construction and can be transferred
   * to another unique_lock by move construction or move assignment. If a
   * mutex lock is owned when the destructor runs ownership will be released.
   *
   * @ingroup mutexes
   */
  template<typename _Mutex>
    class unique_lock
    {
    public:
      typedef _Mutex mutex_type;

      unique_lock() noexcept
      : _M_device(0), _M_owns(false)
      { }

      explicit unique_lock(mutex_type& __m)
      : _M_device(std::__addressof(__m)), _M_owns(false)
      {
        lock();
        _M_owns = true;
      }

      unique_lock(mutex_type& __m, defer_lock_t) noexcept
      : _M_device(std::__addressof(__m)), _M_owns(false)
      { }

      unique_lock(mutex_type& __m, try_to_lock_t)
      : _M_device(std::__addressof(__m)), _M_owns(_M_device->try_lock())
      { }

      unique_lock(mutex_type& __m, adopt_lock_t) noexcept
      : _M_device(std::__addressof(__m)), _M_owns(true)
      {
        // XXX calling thread owns mutex
      }

      template<typename _Clock, typename _Duration>
        unique_lock(mutex_type& __m,
                    const chrono::time_point<_Clock, _Duration>& __atime)
        : _M_device(std::__addressof(__m)),
          _M_owns(_M_device->try_lock_until(__atime))
        { }

      template<typename _Rep, typename _Period>
        unique_lock(mutex_type& __m,
                    const chrono::duration<_Rep, _Period>& __rtime)
        : _M_device(std::__addressof(__m)),
          _M_owns(_M_device->try_lock_for(__rtime))
        { }

      ~unique_lock()
      {
        if (_M_owns)
          unlock();
      }

      unique_lock(const unique_lock&) = delete;
      unique_lock& operator=(const unique_lock&) = delete;

      unique_lock(unique_lock&& __u) noexcept
      : _M_device(__u._M_device), _M_owns(__u._M_owns)
      {
        __u._M_device = 0;
        __u._M_owns = false;
      }

      unique_lock& operator=(unique_lock&& __u) noexcept
      {
        if(_M_owns)
          unlock();

        unique_lock(std::move(__u)).swap(*this);

        __u._M_device = 0;
        __u._M_owns = false;

        return *this;
      }

      void
      lock()
      {
        if (!_M_device)
          __throw_system_error(int(errc::operation_not_permitted));
        else if (_M_owns)
          __throw_system_error(int(errc::resource_deadlock_would_occur));
        else
          {
            _M_device->lock();
            _M_owns = true;
          }
      }

      bool
      try_lock()
      {
        if (!_M_device)
          __throw_system_error(int(errc::operation_not_permitted));
        else if (_M_owns)
          __throw_system_error(int(errc::resource_deadlock_would_occur));
        else
          {
            _M_owns = _M_device->try_lock();
            return _M_owns;
          }
      }

      template<typename _Clock, typename _Duration>
        bool
        try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
        {
          if (!_M_device)
            __throw_system_error(int(errc::operation_not_permitted));
          else if (_M_owns)
            __throw_system_error(int(errc::resource_deadlock_would_occur));
          else
            {
              _M_owns = _M_device->try_lock_until(__atime);
              return _M_owns;
            }
        }

      template<typename _Rep, typename _Period>
        bool
        try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
        {
          if (!_M_device)
            __throw_system_error(int(errc::operation_not_permitted));
          else if (_M_owns)
            __throw_system_error(int(errc::resource_deadlock_would_occur));
          else
            {
              _M_owns = _M_device->try_lock_for(__rtime);
              return _M_owns;
            }
         }

      void
      unlock()
      {
        if (!_M_owns)
          __throw_system_error(int(errc::operation_not_permitted));
        else if (_M_device)
          {
            _M_device->unlock();
            _M_owns = false;
          }
      }

      void
      swap(unique_lock& __u) noexcept
      {
        std::swap(_M_device, __u._M_device);
        std::swap(_M_owns, __u._M_owns);
      }

      mutex_type*
      release() noexcept
      {
        mutex_type* __ret = _M_device;
        _M_device = 0;
        _M_owns = false;
        return __ret;
      }

      bool
      owns_lock() const noexcept
      { return _M_owns; }

      explicit operator bool() const noexcept
      { return owns_lock(); }

      mutex_type*
      mutex() const noexcept
      { return _M_device; }

    private:
      mutex_type*       _M_device;
      bool              _M_owns;
    };

  /// Swap overload for unique_lock objects.
  /// @relates unique_lock
  template<typename _Mutex>
    inline void
    swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept
    { __x.swap(__y); }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif // C++11
#endif // _GLIBCXX_UNIQUE_LOCK_H
Revision:	1166
Committed:	Tue Oct 26 14:22:36 2021 UTC (4 years ago) by rossy
Content type:	text/x-chdr
File size:	6143 byte(s)
Log Message:	Daodan: Replace MinGW build env with an up-to-date MSYS2 env
#	Content
1	// std::unique_lock implementation -- C++ --
2
3	// Copyright (C) 2008-2021 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_lock.h
26	* This is an internal header file, included by other library headers.
27	* Do not attempt to use it directly. @headername{mutex}
28	*/
29
30	#ifndef _GLIBCXX_UNIQUE_LOCK_H
31	#define _GLIBCXX_UNIQUE_LOCK_H 1
32
33	#pragma GCC system_header
34
35	#if __cplusplus < 201103L
36	# include <bits/c++0x_warning.h>
37	#else
38
39	#include <chrono>
40	#include <bits/move.h> // for std::swap
41	#include <bits/std_mutex.h> // for std::defer_lock_t
42
43	namespace std _GLIBCXX_VISIBILITY(default)
44	{
45	_GLIBCXX_BEGIN_NAMESPACE_VERSION
46
47	/** @brief A movable scoped lock type.
48	*
49	* A unique_lock controls mutex ownership within a scope. Ownership of the
50	* mutex can be delayed until after construction and can be transferred
51	* to another unique_lock by move construction or move assignment. If a
52	* mutex lock is owned when the destructor runs ownership will be released.
53	*
54	* @ingroup mutexes
55	*/
56	template<typename _Mutex>
57	class unique_lock
58	{
59	public:
60	typedef _Mutex mutex_type;
61
62	unique_lock() noexcept
63	: _M_device(0), _M_owns(false)
64	{ }
65
66	explicit unique_lock(mutex_type& __m)
67	: _M_device(std::__addressof(__m)), _M_owns(false)
68	{
69	lock();
70	_M_owns = true;
71	}
72
73	unique_lock(mutex_type& __m, defer_lock_t) noexcept
74	: _M_device(std::__addressof(__m)), _M_owns(false)
75	{ }
76
77	unique_lock(mutex_type& __m, try_to_lock_t)
78	: _M_device(std::__addressof(__m)), _M_owns(_M_device->try_lock())
79	{ }
80
81	unique_lock(mutex_type& __m, adopt_lock_t) noexcept
82	: _M_device(std::__addressof(__m)), _M_owns(true)
83	{
84	// XXX calling thread owns mutex
85	}
86
87	template<typename _Clock, typename _Duration>
88	unique_lock(mutex_type& __m,
89	const chrono::time_point<_Clock, _Duration>& __atime)
90	: _M_device(std::__addressof(__m)),
91	_M_owns(_M_device->try_lock_until(__atime))
92	{ }
93
94	template<typename _Rep, typename _Period>
95	unique_lock(mutex_type& __m,
96	const chrono::duration<_Rep, _Period>& __rtime)
97	: _M_device(std::__addressof(__m)),
98	_M_owns(_M_device->try_lock_for(__rtime))
99	{ }
100
101	~unique_lock()
102	{
103	if (_M_owns)
104	unlock();
105	}
106
107	unique_lock(const unique_lock&) = delete;
108	unique_lock& operator=(const unique_lock&) = delete;
109
110	unique_lock(unique_lock&& __u) noexcept
111	: _M_device(__u._M_device), _M_owns(__u._M_owns)
112	{
113	__u._M_device = 0;
114	__u._M_owns = false;
115	}
116
117	unique_lock& operator=(unique_lock&& __u) noexcept
118	{
119	if(_M_owns)
120	unlock();
121
122	unique_lock(std::move(__u)).swap(*this);
123
124	__u._M_device = 0;
125	__u._M_owns = false;
126
127	return *this;
128	}
129
130	void
131	lock()
132	{
133	if (!_M_device)
134	__throw_system_error(int(errc::operation_not_permitted));
135	else if (_M_owns)
136	__throw_system_error(int(errc::resource_deadlock_would_occur));
137	else
138	{
139	_M_device->lock();
140	_M_owns = true;
141	}
142	}
143
144	bool
145	try_lock()
146	{
147	if (!_M_device)
148	__throw_system_error(int(errc::operation_not_permitted));
149	else if (_M_owns)
150	__throw_system_error(int(errc::resource_deadlock_would_occur));
151	else
152	{
153	_M_owns = _M_device->try_lock();
154	return _M_owns;
155	}
156	}
157
158	template<typename _Clock, typename _Duration>
159	bool
160	try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
161	{
162	if (!_M_device)
163	__throw_system_error(int(errc::operation_not_permitted));
164	else if (_M_owns)
165	__throw_system_error(int(errc::resource_deadlock_would_occur));
166	else
167	{
168	_M_owns = _M_device->try_lock_until(__atime);
169	return _M_owns;
170	}
171	}
172
173	template<typename _Rep, typename _Period>
174	bool
175	try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
176	{
177	if (!_M_device)
178	__throw_system_error(int(errc::operation_not_permitted));
179	else if (_M_owns)
180	__throw_system_error(int(errc::resource_deadlock_would_occur));
181	else
182	{
183	_M_owns = _M_device->try_lock_for(__rtime);
184	return _M_owns;
185	}
186	}
187
188	void
189	unlock()
190	{
191	if (!_M_owns)
192	__throw_system_error(int(errc::operation_not_permitted));
193	else if (_M_device)
194	{
195	_M_device->unlock();
196	_M_owns = false;
197	}
198	}
199
200	void
201	swap(unique_lock& __u) noexcept
202	{
203	std::swap(_M_device, __u._M_device);
204	std::swap(_M_owns, __u._M_owns);
205	}
206
207	mutex_type*
208	release() noexcept
209	{
210	mutex_type* __ret = _M_device;
211	_M_device = 0;
212	_M_owns = false;
213	return __ret;
214	}
215
216	bool
217	owns_lock() const noexcept
218	{ return _M_owns; }
219
220	explicit operator bool() const noexcept
221	{ return owns_lock(); }
222
223	mutex_type*
224	mutex() const noexcept
225	{ return _M_device; }
226
227	private:
228	mutex_type* _M_device;
229	bool _M_owns;
230	};
231
232	/// Swap overload for unique_lock objects.
233	/// @relates unique_lock
234	template<typename _Mutex>
235	inline void
236	swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept
237	{ __x.swap(__y); }
238
239	_GLIBCXX_END_NAMESPACE_VERSION
240	} // namespace
241
242	#endif // C++11
243	#endif // _GLIBCXX_UNIQUE_LOCK_H