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// -*-c++-*-
// vim: set ft=cpp:
/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file LICENSE.rst or https://cmake.org/licensing for details. */
#pragma once
#if __cplusplus >= 201402L || defined(_MSVC_LANG) && _MSVC_LANG >= 201402L
# define CMake_HAVE_CXX_SHARED_LOCK
#endif
#if __cplusplus >= 201703L || defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
# define CMake_HAVE_CXX_SHARED_MUTEX
#endif
#if defined(CMake_HAVE_CXX_SHARED_LOCK)
# include <shared_mutex> // IWYU pragma: export
#endif
#if !defined(CMake_HAVE_CXX_SHARED_MUTEX)
# include <cm3p/uv.h>
#endif
namespace cm {
#if defined(CMake_HAVE_CXX_SHARED_MUTEX)
using std::shared_mutex;
#else
class shared_mutex
{
uv_rwlock_t _M_;
public:
using native_handle_type = uv_rwlock_t*;
shared_mutex() { uv_rwlock_init(&_M_); }
~shared_mutex() { uv_rwlock_destroy(&_M_); }
shared_mutex(shared_mutex const&) = delete;
shared_mutex& operator=(shared_mutex const&) = delete;
void lock() { uv_rwlock_wrlock(&_M_); }
bool try_lock() { return uv_rwlock_trywrlock(&_M_) == 0; }
void unlock() { uv_rwlock_wrunlock(&_M_); }
void lock_shared() { uv_rwlock_rdlock(&_M_); }
void unlock_shared() { uv_rwlock_rdunlock(&_M_); }
native_handle_type native_handle() { return &_M_; }
};
#endif
#if defined(CMake_HAVE_CXX_SHARED_LOCK)
using std::shared_lock;
#else
template <typename T>
class shared_lock
{
T& _mutex;
public:
using mutex_type = T;
shared_lock(T& m)
: _mutex(m)
{
_mutex.lock_shared();
}
~shared_lock() { _mutex.unlock_shared(); }
shared_lock(shared_lock const&) = delete;
shared_lock& operator=(shared_lock const&) = delete;
};
#endif
}
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