diff options
Diffstat (limited to 'chromium/buildtools/third_party/libc++/trunk/src/mutex.cpp')
| -rw-r--r-- | chromium/buildtools/third_party/libc++/trunk/src/mutex.cpp | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/chromium/buildtools/third_party/libc++/trunk/src/mutex.cpp b/chromium/buildtools/third_party/libc++/trunk/src/mutex.cpp new file mode 100644 index 00000000000..127e67a2627 --- /dev/null +++ b/chromium/buildtools/third_party/libc++/trunk/src/mutex.cpp @@ -0,0 +1,284 @@ +//===------------------------- 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 +#ifndef _LIBCPP_HAS_NO_THREADS + +const defer_lock_t defer_lock = {}; +const try_to_lock_t try_to_lock = {}; +const adopt_lock_t adopt_lock = {}; + +mutex::~mutex() +{ + pthread_mutex_destroy(&__m_); +} + +void +mutex::lock() +{ + int ec = pthread_mutex_lock(&__m_); + if (ec) + __throw_system_error(ec, "mutex lock failed"); +} + +bool +mutex::try_lock() _NOEXCEPT +{ + return pthread_mutex_trylock(&__m_) == 0; +} + +void +mutex::unlock() _NOEXCEPT +{ + int ec = pthread_mutex_unlock(&__m_); + (void)ec; + assert(ec == 0); +} + +// recursive_mutex + +recursive_mutex::recursive_mutex() +{ + pthread_mutexattr_t attr; + int ec = pthread_mutexattr_init(&attr); + if (ec) + goto fail; + ec = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); + if (ec) + { + pthread_mutexattr_destroy(&attr); + goto fail; + } + ec = pthread_mutex_init(&__m_, &attr); + if (ec) + { + pthread_mutexattr_destroy(&attr); + goto fail; + } + ec = pthread_mutexattr_destroy(&attr); + if (ec) + { + pthread_mutex_destroy(&__m_); + goto fail; + } + return; +fail: + __throw_system_error(ec, "recursive_mutex constructor failed"); +} + +recursive_mutex::~recursive_mutex() +{ + int e = pthread_mutex_destroy(&__m_); + (void)e; + assert(e == 0); +} + +void +recursive_mutex::lock() +{ + int ec = pthread_mutex_lock(&__m_); + if (ec) + __throw_system_error(ec, "recursive_mutex lock failed"); +} + +void +recursive_mutex::unlock() _NOEXCEPT +{ + int e = pthread_mutex_unlock(&__m_); + (void)e; + assert(e == 0); +} + +bool +recursive_mutex::try_lock() _NOEXCEPT +{ + return pthread_mutex_trylock(&__m_) == 0; +} + +// timed_mutex + +timed_mutex::timed_mutex() + : __locked_(false) +{ +} + +timed_mutex::~timed_mutex() +{ + lock_guard<mutex> _(__m_); +} + +void +timed_mutex::lock() +{ + unique_lock<mutex> lk(__m_); + while (__locked_) + __cv_.wait(lk); + __locked_ = true; +} + +bool +timed_mutex::try_lock() _NOEXCEPT +{ + unique_lock<mutex> lk(__m_, try_to_lock); + if (lk.owns_lock() && !__locked_) + { + __locked_ = true; + return true; + } + return false; +} + +void +timed_mutex::unlock() _NOEXCEPT +{ + lock_guard<mutex> _(__m_); + __locked_ = false; + __cv_.notify_one(); +} + +// recursive_timed_mutex + +recursive_timed_mutex::recursive_timed_mutex() + : __count_(0), + __id_(0) +{ +} + +recursive_timed_mutex::~recursive_timed_mutex() +{ + lock_guard<mutex> _(__m_); +} + +void +recursive_timed_mutex::lock() +{ + pthread_t id = pthread_self(); + unique_lock<mutex> lk(__m_); + if (pthread_equal(id, __id_)) + { + if (__count_ == numeric_limits<size_t>::max()) + __throw_system_error(EAGAIN, "recursive_timed_mutex lock limit reached"); + ++__count_; + return; + } + while (__count_ != 0) + __cv_.wait(lk); + __count_ = 1; + __id_ = id; +} + +bool +recursive_timed_mutex::try_lock() _NOEXCEPT +{ + pthread_t id = pthread_self(); + unique_lock<mutex> lk(__m_, try_to_lock); + if (lk.owns_lock() && (__count_ == 0 || pthread_equal(id, __id_))) + { + if (__count_ == numeric_limits<size_t>::max()) + return false; + ++__count_; + __id_ = id; + return true; + } + return false; +} + +void +recursive_timed_mutex::unlock() _NOEXCEPT +{ + unique_lock<mutex> lk(__m_); + if (--__count_ == 0) + { + __id_ = 0; + lk.unlock(); + __cv_.notify_one(); + } +} + +#endif // !_LIBCPP_HAS_NO_THREADS + +// 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. + +#ifndef _LIBCPP_HAS_NO_THREADS +static pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t cv = PTHREAD_COND_INITIALIZER; +#endif + +/// 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*)) +{ +#if defined(_LIBCPP_HAS_NO_THREADS) + if (flag == 0) + { +#ifndef _LIBCPP_NO_EXCEPTIONS + try + { +#endif // _LIBCPP_NO_EXCEPTIONS + flag = 1; + func(arg); + flag = ~0ul; +#ifndef _LIBCPP_NO_EXCEPTIONS + } + catch (...) + { + flag = 0ul; + throw; + } +#endif // _LIBCPP_NO_EXCEPTIONS + } +#else // !_LIBCPP_HAS_NO_THREADS + pthread_mutex_lock(&mut); + while (flag == 1) + pthread_cond_wait(&cv, &mut); + if (flag == 0) + { +#ifndef _LIBCPP_NO_EXCEPTIONS + try + { +#endif // _LIBCPP_NO_EXCEPTIONS + __libcpp_relaxed_store(&flag, 1ul); + pthread_mutex_unlock(&mut); + func(arg); + pthread_mutex_lock(&mut); + __libcpp_relaxed_store(&flag, ~0ul); + pthread_mutex_unlock(&mut); + pthread_cond_broadcast(&cv); +#ifndef _LIBCPP_NO_EXCEPTIONS + } + catch (...) + { + pthread_mutex_lock(&mut); + __libcpp_relaxed_store(&flag, 0ul); + pthread_mutex_unlock(&mut); + pthread_cond_broadcast(&cv); + throw; + } +#endif // _LIBCPP_NO_EXCEPTIONS + } + else + pthread_mutex_unlock(&mut); +#endif // !_LIBCPP_HAS_NO_THREADS + +} + +_LIBCPP_END_NAMESPACE_STD |