123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248 |
- // std::mutex implementation -*- C++ -*-
- // Copyright (C) 2003-2022 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/std_mutex.h
- * This is an internal header file, included by other library headers.
- * Do not attempt to use it directly. @headername{mutex}
- */
- #ifndef _GLIBCXX_MUTEX_H
- #define _GLIBCXX_MUTEX_H 1
- #pragma GCC system_header
- #if __cplusplus < 201103L
- # include <bits/c++0x_warning.h>
- #else
- #include <system_error>
- #include <bits/functexcept.h>
- #include <bits/gthr.h>
- namespace std _GLIBCXX_VISIBILITY(default)
- {
- _GLIBCXX_BEGIN_NAMESPACE_VERSION
- /**
- * @defgroup mutexes Mutexes
- * @ingroup concurrency
- *
- * Classes for mutex support.
- * @{
- */
- #ifdef _GLIBCXX_HAS_GTHREADS
- // Common base class for std::mutex and std::timed_mutex
- class __mutex_base
- {
- protected:
- typedef __gthread_mutex_t __native_type;
- #ifdef __GTHREAD_MUTEX_INIT
- __native_type _M_mutex = __GTHREAD_MUTEX_INIT;
- constexpr __mutex_base() noexcept = default;
- #else
- __native_type _M_mutex;
- __mutex_base() noexcept
- {
- // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
- __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
- }
- ~__mutex_base() noexcept { __gthread_mutex_destroy(&_M_mutex); }
- #endif
- __mutex_base(const __mutex_base&) = delete;
- __mutex_base& operator=(const __mutex_base&) = delete;
- };
- /// The standard mutex type.
- class mutex : private __mutex_base
- {
- public:
- typedef __native_type* native_handle_type;
- #ifdef __GTHREAD_MUTEX_INIT
- constexpr
- #endif
- mutex() noexcept = default;
- ~mutex() = default;
- mutex(const mutex&) = delete;
- mutex& operator=(const mutex&) = delete;
- void
- lock()
- {
- int __e = __gthread_mutex_lock(&_M_mutex);
- // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
- if (__e)
- __throw_system_error(__e);
- }
- bool
- try_lock() noexcept
- {
- // XXX EINVAL, EAGAIN, EBUSY
- return !__gthread_mutex_trylock(&_M_mutex);
- }
- void
- unlock()
- {
- // XXX EINVAL, EAGAIN, EPERM
- __gthread_mutex_unlock(&_M_mutex);
- }
- native_handle_type
- native_handle() noexcept
- { return &_M_mutex; }
- };
- // Implementation details for std::condition_variable
- class __condvar
- {
- using timespec = __gthread_time_t;
- public:
- __condvar() noexcept
- {
- #ifndef __GTHREAD_COND_INIT
- __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
- #endif
- }
- ~__condvar()
- {
- int __e __attribute__((__unused__)) = __gthread_cond_destroy(&_M_cond);
- __glibcxx_assert(__e != EBUSY); // threads are still blocked
- }
- __condvar(const __condvar&) = delete;
- __condvar& operator=(const __condvar&) = delete;
- __gthread_cond_t* native_handle() noexcept { return &_M_cond; }
- // Expects: Calling thread has locked __m.
- void
- wait(mutex& __m)
- {
- int __e __attribute__((__unused__))
- = __gthread_cond_wait(&_M_cond, __m.native_handle());
- __glibcxx_assert(__e == 0);
- }
- void
- wait_until(mutex& __m, timespec& __abs_time)
- {
- __gthread_cond_timedwait(&_M_cond, __m.native_handle(), &__abs_time);
- }
- #ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
- void
- wait_until(mutex& __m, clockid_t __clock, timespec& __abs_time)
- {
- pthread_cond_clockwait(&_M_cond, __m.native_handle(), __clock,
- &__abs_time);
- }
- #endif
- void
- notify_one() noexcept
- {
- int __e __attribute__((__unused__)) = __gthread_cond_signal(&_M_cond);
- __glibcxx_assert(__e == 0);
- }
- void
- notify_all() noexcept
- {
- int __e __attribute__((__unused__)) = __gthread_cond_broadcast(&_M_cond);
- __glibcxx_assert(__e == 0);
- }
- protected:
- #ifdef __GTHREAD_COND_INIT
- __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
- #else
- __gthread_cond_t _M_cond;
- #endif
- };
- #endif // _GLIBCXX_HAS_GTHREADS
- /// Do not acquire ownership of the mutex.
- struct defer_lock_t { explicit defer_lock_t() = default; };
- /// Try to acquire ownership of the mutex without blocking.
- struct try_to_lock_t { explicit try_to_lock_t() = default; };
- /// Assume the calling thread has already obtained mutex ownership
- /// and manage it.
- struct adopt_lock_t { explicit adopt_lock_t() = default; };
- /// Tag used to prevent a scoped lock from acquiring ownership of a mutex.
- _GLIBCXX17_INLINE constexpr defer_lock_t defer_lock { };
- /// Tag used to prevent a scoped lock from blocking if a mutex is locked.
- _GLIBCXX17_INLINE constexpr try_to_lock_t try_to_lock { };
- /// Tag used to make a scoped lock take ownership of a locked mutex.
- _GLIBCXX17_INLINE constexpr adopt_lock_t adopt_lock { };
- /** @brief A simple scoped lock type.
- *
- * A lock_guard controls mutex ownership within a scope, releasing
- * ownership in the destructor.
- */
- template<typename _Mutex>
- class lock_guard
- {
- public:
- typedef _Mutex mutex_type;
- explicit lock_guard(mutex_type& __m) : _M_device(__m)
- { _M_device.lock(); }
- lock_guard(mutex_type& __m, adopt_lock_t) noexcept : _M_device(__m)
- { } // calling thread owns mutex
- ~lock_guard()
- { _M_device.unlock(); }
- lock_guard(const lock_guard&) = delete;
- lock_guard& operator=(const lock_guard&) = delete;
- private:
- mutex_type& _M_device;
- };
- /// @} group mutexes
- _GLIBCXX_END_NAMESPACE_VERSION
- } // namespace
- #endif // C++11
- #endif // _GLIBCXX_MUTEX_H
|