| // std::mutex implementation -*- C++ -*- |
| |
| // Copyright (C) 2003-2016 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> |
| #include <bits/move.h> // for std::swap |
| |
| #ifdef _GLIBCXX_USE_C99_STDINT_TR1 |
| |
| 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() |
| { return &_M_mutex; } |
| }; |
| |
| #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. |
| constexpr defer_lock_t defer_lock { }; |
| |
| /// Tag used to prevent a scoped lock from blocking if a mutex is locked. |
| constexpr try_to_lock_t try_to_lock { }; |
| |
| /// Tag used to make a scoped lock take ownership of a locked mutex. |
| 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) : _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; |
| }; |
| |
| /** @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. |
| */ |
| 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) |
| : _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; // XXX use atomic_bool |
| }; |
| |
| /// Swap overload for unique_lock objects. |
| template<typename _Mutex> |
| inline void |
| swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept |
| { __x.swap(__y); } |
| |
| // @} group mutexes |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| #endif // _GLIBCXX_USE_C99_STDINT_TR1 |
| |
| #endif // C++11 |
| |
| #endif // _GLIBCXX_MUTEX_H |