8d2cddc125
* include/std/shared_mutex: Implement N3659. * include/bits/c++14_warning.h: New. * include/Makefile.am: Add new headers. * include/Makefile.in: Regenerate. * testsuite/30_threads/shared_lock/cons/1.cc: New. * testsuite/30_threads/shared_lock/locking/2.cc: New. * testsuite/30_threads/shared_lock/cons/2.cc: New. * testsuite/30_threads/shared_lock/locking/3.cc: New. * testsuite/30_threads/shared_lock/cons/3.cc: New. * testsuite/30_threads/shared_lock/locking/4.cc: New. * testsuite/30_threads/shared_lock/cons/4.cc: New. * testsuite/30_threads/shared_lock/modifiers/1.cc: New. * testsuite/30_threads/shared_lock/cons/5.cc: New. * testsuite/30_threads/shared_lock/modifiers/2.cc: New. * testsuite/30_threads/shared_lock/cons/6.cc: New. * testsuite/30_threads/shared_lock/requirements/ explicit_instantiation.cc: New. * testsuite/30_threads/shared_lock/locking/1.cc: New. * testsuite/30_threads/shared_lock/requirements/typedefs.cc: New. * testsuite/30_threads/shared_mutex/cons/1.cc: New. * testsuite/30_threads/shared_mutex/cons/assign_neg.cc: New. * testsuite/30_threads/shared_mutex/cons/copy_neg.cc: New. * testsuite/30_threads/shared_mutex/requirements/ standard_layout.cc: New. * testsuite/30_threads/shared_mutex/try_lock/1.cc: New. * testsuite/30_threads/shared_mutex/try_lock/2.cc: New. From-SVN: r200134
435 lines
10 KiB
C++
435 lines
10 KiB
C++
// <shared_mutex> -*- C++ -*-
|
|
|
|
// Copyright (C) 2013 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 include/shared_mutex
|
|
* This is a Standard C++ Library header.
|
|
*/
|
|
|
|
#ifndef _GLIBCXX_SHARED_MUTEX
|
|
#define _GLIBCXX_SHARED_MUTEX 1
|
|
|
|
#pragma GCC system_header
|
|
|
|
#if __cplusplus <= 201103L
|
|
# include <bits/c++14_warning.h>
|
|
#else
|
|
|
|
#include <bits/c++config.h>
|
|
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
|
|
# include <mutex>
|
|
# include <condition_variable>
|
|
#endif
|
|
#include <bits/functexcept.h>
|
|
|
|
namespace std _GLIBCXX_VISIBILITY(default)
|
|
{
|
|
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
|
|
|
/**
|
|
* @ingroup mutexes
|
|
* @{
|
|
*/
|
|
|
|
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
|
|
/// shared_mutex
|
|
class shared_mutex
|
|
{
|
|
#if _GTHREAD_USE_MUTEX_TIMEDLOCK
|
|
struct _Mutex : mutex
|
|
{
|
|
typedef chrono::steady_clock __clock_t;
|
|
|
|
template <class _Rep, class _Period>
|
|
bool
|
|
try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
|
|
{ return __try_lock_for_impl(__rtime); }
|
|
|
|
template <class _Clock, class _Duration>
|
|
bool
|
|
try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
|
|
{
|
|
chrono::time_point<_Clock, chrono::seconds> __s =
|
|
chrono::time_point_cast<chrono::seconds>(__atime);
|
|
|
|
chrono::nanoseconds __ns =
|
|
chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
|
|
|
|
__gthread_time_t __ts = {
|
|
static_cast<std::time_t>(__s.time_since_epoch().count()),
|
|
static_cast<long>(__ns.count())
|
|
};
|
|
|
|
return !__gthread_mutex_timedlock(native_handle(), &__ts);
|
|
}
|
|
|
|
private:
|
|
template<typename _Rep, typename _Period>
|
|
typename enable_if<
|
|
ratio_less_equal<__clock_t::period, _Period>::value, bool>::type
|
|
__try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime)
|
|
{
|
|
__clock_t::time_point __atime = __clock_t::now()
|
|
+ chrono::duration_cast<__clock_t::duration>(__rtime);
|
|
|
|
return try_lock_until(__atime);
|
|
}
|
|
|
|
template <typename _Rep, typename _Period>
|
|
typename enable_if<
|
|
!ratio_less_equal<__clock_t::period, _Period>::value, bool>::type
|
|
__try_lock_for_impl(const chrono::duration<_Rep, _Period>& __rtime)
|
|
{
|
|
__clock_t::time_point __atime = __clock_t::now()
|
|
+ ++chrono::duration_cast<__clock_t::duration>(__rtime);
|
|
|
|
return try_lock_until(__atime);
|
|
}
|
|
};
|
|
#else
|
|
typedef mutex _Mutex;
|
|
#endif
|
|
|
|
// Based on Howard Hinnant's reference implementation from N2406
|
|
|
|
_Mutex _M_mut;
|
|
condition_variable _M_gate1;
|
|
condition_variable _M_gate2;
|
|
unsigned _M_state;
|
|
|
|
static constexpr unsigned _S_write_entered
|
|
= 1U << (sizeof(unsigned)*__CHAR_BIT__ - 1);
|
|
static constexpr unsigned _M_n_readers = ~_S_write_entered;
|
|
|
|
public:
|
|
shared_mutex() : _M_state(0) {}
|
|
|
|
~shared_mutex()
|
|
{
|
|
_GLIBCXX_DEBUG_ASSERT( _M_state == 0 );
|
|
}
|
|
|
|
shared_mutex(const shared_mutex&) = delete;
|
|
shared_mutex& operator=(const shared_mutex&) = delete;
|
|
|
|
// Exclusive ownership
|
|
|
|
void
|
|
lock()
|
|
{
|
|
unique_lock<mutex> __lk(_M_mut);
|
|
while (_M_state & _S_write_entered)
|
|
_M_gate1.wait(__lk);
|
|
_M_state |= _S_write_entered;
|
|
while (_M_state & _M_n_readers)
|
|
_M_gate2.wait(__lk);
|
|
}
|
|
|
|
bool
|
|
try_lock()
|
|
{
|
|
unique_lock<mutex> __lk(_M_mut, try_to_lock);
|
|
if (__lk.owns_lock() && _M_state == 0)
|
|
{
|
|
_M_state = _S_write_entered;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
#if _GTHREAD_USE_MUTEX_TIMEDLOCK
|
|
template<typename _Rep, typename _Period>
|
|
bool
|
|
try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
|
|
{
|
|
unique_lock<_Mutex> __lk(_M_mut, __rel_time);
|
|
if (__lk.owns_lock() && _M_state == 0)
|
|
{
|
|
_M_state = _S_write_entered;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
template<typename _Clock, typename _Duration>
|
|
bool
|
|
try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time)
|
|
{
|
|
unique_lock<_Mutex> __lk(_M_mut, __abs_time);
|
|
if (__lk.owns_lock() && _M_state == 0)
|
|
{
|
|
_M_state = _S_write_entered;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
#endif
|
|
|
|
void
|
|
unlock()
|
|
{
|
|
{
|
|
lock_guard<_Mutex> __lk(_M_mut);
|
|
_M_state = 0;
|
|
}
|
|
_M_gate1.notify_all();
|
|
}
|
|
|
|
// Shared ownership
|
|
|
|
void
|
|
lock_shared()
|
|
{
|
|
unique_lock<mutex> __lk(_M_mut);
|
|
while ((_M_state & _S_write_entered)
|
|
|| (_M_state & _M_n_readers) == _M_n_readers)
|
|
{
|
|
_M_gate1.wait(__lk);
|
|
}
|
|
unsigned __num_readers = (_M_state & _M_n_readers) + 1;
|
|
_M_state &= ~_M_n_readers;
|
|
_M_state |= __num_readers;
|
|
}
|
|
|
|
bool
|
|
try_lock_shared()
|
|
{
|
|
unique_lock<_Mutex> __lk(_M_mut, try_to_lock);
|
|
unsigned __num_readers = _M_state & _M_n_readers;
|
|
if (__lk.owns_lock() && !(_M_state & _S_write_entered)
|
|
&& __num_readers != _M_n_readers)
|
|
{
|
|
++__num_readers;
|
|
_M_state &= ~_M_n_readers;
|
|
_M_state |= __num_readers;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
#if _GTHREAD_USE_MUTEX_TIMEDLOCK
|
|
template<typename _Rep, typename _Period>
|
|
bool
|
|
try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time)
|
|
{
|
|
unique_lock<_Mutex> __lk(_M_mut, __rel_time);
|
|
if (__lk.owns_lock())
|
|
{
|
|
unsigned __num_readers = _M_state & _M_n_readers;
|
|
if (!(_M_state & _S_write_entered)
|
|
&& __num_readers != _M_n_readers)
|
|
{
|
|
++__num_readers;
|
|
_M_state &= ~_M_n_readers;
|
|
_M_state |= __num_readers;
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
template <typename _Clock, typename _Duration>
|
|
bool
|
|
try_lock_shared_until(const chrono::time_point<_Clock,
|
|
_Duration>& __abs_time)
|
|
{
|
|
unique_lock<_Mutex> __lk(_M_mut, __abs_time);
|
|
if (__lk.owns_lock())
|
|
{
|
|
unsigned __num_readers = _M_state & _M_n_readers;
|
|
if (!(_M_state & _S_write_entered)
|
|
&& __num_readers != _M_n_readers)
|
|
{
|
|
++__num_readers;
|
|
_M_state &= ~_M_n_readers;
|
|
_M_state |= __num_readers;
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
#endif
|
|
|
|
void
|
|
unlock_shared()
|
|
{
|
|
lock_guard<_Mutex> __lk(_M_mut);
|
|
unsigned __num_readers = (_M_state & _M_n_readers) - 1;
|
|
_M_state &= ~_M_n_readers;
|
|
_M_state |= __num_readers;
|
|
if (_M_state & _S_write_entered)
|
|
{
|
|
if (__num_readers == 0)
|
|
_M_gate2.notify_one();
|
|
}
|
|
else
|
|
{
|
|
if (__num_readers == _M_n_readers - 1)
|
|
_M_gate1.notify_one();
|
|
}
|
|
}
|
|
};
|
|
#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
|
|
|
|
/// shared_lock
|
|
template<typename _Mutex>
|
|
class shared_lock
|
|
{
|
|
public:
|
|
typedef _Mutex mutex_type;
|
|
|
|
// Shared locking
|
|
|
|
shared_lock() noexcept : _M_pm(nullptr), _M_owns(false) { }
|
|
|
|
explicit
|
|
shared_lock(mutex_type& __m) : _M_pm(&__m), _M_owns(true)
|
|
{ __m.lock_shared(); }
|
|
|
|
shared_lock(mutex_type& __m, defer_lock_t) noexcept
|
|
: _M_pm(&__m), _M_owns(false) { }
|
|
|
|
shared_lock(mutex_type& __m, try_to_lock_t)
|
|
: _M_pm(&__m), _M_owns(__m.try_lock_shared()) { }
|
|
|
|
shared_lock(mutex_type& __m, adopt_lock_t)
|
|
: _M_pm(&__m), _M_owns(true) { }
|
|
|
|
template<typename _Clock, typename _Duration>
|
|
shared_lock(mutex_type& __m,
|
|
const chrono::time_point<_Clock, _Duration>& __abs_time)
|
|
: _M_pm(&__m), _M_owns(__m.try_lock_shared_until(__abs_time)) { }
|
|
|
|
template<typename _Rep, typename _Period>
|
|
shared_lock(mutex_type& __m,
|
|
const chrono::duration<_Rep, _Period>& __rel_time)
|
|
: _M_pm(&__m), _M_owns(__m.try_lock_shared_for(__rel_time)) { }
|
|
|
|
~shared_lock()
|
|
{
|
|
if (_M_owns)
|
|
_M_pm->unlock_shared();
|
|
}
|
|
|
|
shared_lock(shared_lock const&) = delete;
|
|
shared_lock& operator=(shared_lock const&) = delete;
|
|
|
|
shared_lock(shared_lock&& __sl) noexcept : shared_lock()
|
|
{ swap(__sl); }
|
|
|
|
shared_lock&
|
|
operator=(shared_lock&& __sl) noexcept
|
|
{ shared_lock(std::move(__sl)).swap(*this); }
|
|
|
|
void
|
|
lock()
|
|
{
|
|
_M_lockable();
|
|
_M_pm->lock_shared();
|
|
_M_owns = true;
|
|
}
|
|
|
|
bool
|
|
try_lock()
|
|
{
|
|
_M_lockable();
|
|
return _M_owns = _M_pm->try_lock_shared();
|
|
}
|
|
|
|
template<typename _Rep, typename _Period>
|
|
bool
|
|
try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
|
|
{
|
|
_M_lockable();
|
|
return _M_owns = _M_pm->try_lock_shared_for(__rel_time);
|
|
}
|
|
|
|
template<typename _Clock, typename _Duration>
|
|
bool
|
|
try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time)
|
|
{
|
|
_M_lockable();
|
|
return _M_owns = _M_pm->try_lock_shared_until(__abs_time);
|
|
}
|
|
|
|
void
|
|
unlock()
|
|
{
|
|
if (!_M_owns)
|
|
__throw_system_error(int(errc::resource_deadlock_would_occur));
|
|
_M_pm->unlock_shared();
|
|
_M_owns = false;
|
|
}
|
|
|
|
// Setters
|
|
|
|
void
|
|
swap(shared_lock& __u) noexcept
|
|
{
|
|
std::swap(_M_pm, __u._M_pm);
|
|
std::swap(_M_owns, __u._M_owns);
|
|
}
|
|
|
|
mutex_type*
|
|
release() noexcept
|
|
{
|
|
_M_owns = false;
|
|
return std::exchange(_M_pm, nullptr);
|
|
}
|
|
|
|
// Getters
|
|
|
|
bool owns_lock() const noexcept { return _M_owns; }
|
|
|
|
explicit operator bool() const noexcept { return _M_owns; }
|
|
|
|
mutex_type* mutex() const noexcept { return _M_pm; }
|
|
|
|
private:
|
|
void
|
|
_M_lockable() const
|
|
{
|
|
if (_M_pm == nullptr)
|
|
__throw_system_error(int(errc::operation_not_permitted));
|
|
if (_M_owns)
|
|
__throw_system_error(int(errc::resource_deadlock_would_occur));
|
|
}
|
|
|
|
mutex_type* _M_pm;
|
|
bool _M_owns;
|
|
};
|
|
|
|
/// Swap specialization for shared_lock
|
|
template<typename _Mutex>
|
|
void
|
|
swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) noexcept
|
|
{ __x.swap(__y); }
|
|
|
|
// @} group mutexes
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
|
|
#endif // C++14
|
|
|
|
#endif // _GLIBCXX_SHARED_MUTEX
|