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- //===------------------------- mutex.cpp ----------------------------------===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is dual licensed under the MIT and the University of Illinois Open
- // Source Licenses. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- #define _LIBCPP_BUILDING_MUTEX
- #include "mutex"
- #include "limits"
- #include "system_error"
- #include "cassert"
- #include "include/atomic_support.h"
- _LIBCPP_BEGIN_NAMESPACE_STD
- const defer_lock_t defer_lock = {};
- const try_to_lock_t try_to_lock = {};
- const adopt_lock_t adopt_lock = {};
- mutex::~mutex()
- {
- sgx_thread_mutex_destroy(&__m_);
- }
- void
- mutex::lock()
- {
- int ec = sgx_thread_mutex_lock(&__m_);
- if (ec)
- __throw_system_error(ec, "mutex lock failed");
- }
- bool
- mutex::try_lock() _NOEXCEPT
- {
- return sgx_thread_mutex_trylock(&__m_) == 0;
- }
- void
- mutex::unlock() _NOEXCEPT
- {
- int ec = sgx_thread_mutex_unlock(&__m_);
- (void)ec;
- assert(ec == 0);
- }
- // recursive_mutex
- recursive_mutex::recursive_mutex()
- {
- __m_ = SGX_THREAD_RECURSIVE_MUTEX_INITIALIZER;
- }
- recursive_mutex::~recursive_mutex()
- {
- int e = sgx_thread_mutex_destroy(&__m_);
- (void)e;
- assert(e == 0);
- }
- void
- recursive_mutex::lock()
- {
- int ec = sgx_thread_mutex_lock(&__m_);
- if (ec)
- __throw_system_error(ec, "recursive_mutex lock failed");
- }
- void
- recursive_mutex::unlock() _NOEXCEPT
- {
- int e = sgx_thread_mutex_unlock(&__m_);
- (void)e;
- assert(e == 0);
- }
- bool
- recursive_mutex::try_lock() _NOEXCEPT
- {
- return sgx_thread_mutex_trylock(&__m_) == 0;
- }
- // If dispatch_once_f ever handles C++ exceptions, and if one can get to it
- // without illegal macros (unexpected macros not beginning with _UpperCase or
- // __lowercase), and if it stops spinning waiting threads, then call_once should
- // call into dispatch_once_f instead of here. Relevant radar this code needs to
- // keep in sync with: 7741191.
- #if defined(_LIBCPP_SGX_HAS_CXX_ATOMIC)
- static sgx_thread_mutex_t mut = SGX_THREAD_MUTEX_INITIALIZER;
- static sgx_thread_cond_t cv = SGX_THREAD_COND_INITIALIZER;
- /// NOTE: Changes to flag are done via relaxed atomic stores
- /// even though the accesses are protected by a mutex because threads
- /// just entering 'call_once' concurrently read from flag.
- void
- __call_once(volatile unsigned long & flag, void* arg, void(*func)(void*))
- {
- sgx_thread_mutex_lock(&mut);
- while (flag == 1)
- sgx_thread_cond_wait(&cv, &mut);
- if (flag == 0)
- {
- try
- {
- __libcpp_relaxed_store(&flag, 1ul);
- sgx_thread_mutex_unlock(&mut);
- func(arg);
- sgx_thread_mutex_lock(&mut);
- __libcpp_relaxed_store(&flag, ~0ul);
- sgx_thread_mutex_unlock(&mut);
- sgx_thread_cond_broadcast(&cv);
- }
- catch (...)
- {
- sgx_thread_mutex_lock(&mut);
- __libcpp_relaxed_store(&flag, 0ul);
- sgx_thread_mutex_unlock(&mut);
- sgx_thread_cond_broadcast(&cv);
- throw;
- }
- }
- else
- sgx_thread_mutex_unlock(&mut);
- }
- #endif // defined(_LIBCPP_SGX_HAS_CXX_ATOMIC)
- _LIBCPP_END_NAMESPACE_STD
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