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p-3_I|+ // 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
// .
/** @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
#else
#include
#include // for std::swap
#include // 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
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
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
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