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The C and C++ Include Header Files

/usr/include/c++/11/bits/unique_lock.h


$ cat -n /usr/include/c++/11/bits/unique_lock.h

     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