intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 240 insertions, 0 deletions

diff --git a/contrib/libs/cxxsupp/libcxx/include/semaphore b/contrib/libs/cxxsupp/libcxx/include/semaphore
new file mode 100644
index 0000000000..4f9ecd0461
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/semaphore
@@ -0,0 +1,240 @@
+// -*- C++ -*-
+//===--------------------------- semaphore --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SEMAPHORE
+#define _LIBCPP_SEMAPHORE
+
+/*
+    semaphore synopsis
+
+namespace std {
+
+template<ptrdiff_t least_max_value = implementation-defined>
+class counting_semaphore
+{
+public:
+static constexpr ptrdiff_t max() noexcept;
+
+constexpr explicit counting_semaphore(ptrdiff_t desired);
+~counting_semaphore();
+
+counting_semaphore(const counting_semaphore&) = delete;
+counting_semaphore& operator=(const counting_semaphore&) = delete;
+
+void release(ptrdiff_t update = 1);
+void acquire();
+bool try_acquire() noexcept;
+template<class Rep, class Period>
+    bool try_acquire_for(const chrono::duration<Rep, Period>& rel_time);
+template<class Clock, class Duration>
+    bool try_acquire_until(const chrono::time_point<Clock, Duration>& abs_time);
+
+private:
+ptrdiff_t counter; // exposition only
+};
+
+using binary_semaphore = counting_semaphore<1>;
+
+}
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__threading_support>
+#include <atomic>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+# error <semaphore> is not supported on this single threaded system
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 14
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+/*
+
+__atomic_semaphore_base is the general-case implementation, to be used for
+user-requested least-max values that exceed the OS implementation support
+(incl. when the OS has no support of its own) and for binary semaphores.
+
+It is a typical Dijkstra semaphore algorithm over atomics, wait and notify
+functions. It avoids contention against users' own use of those facilities.
+
+*/
+
+class __atomic_semaphore_base
+{
+    __atomic_base<ptrdiff_t> __a;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit __atomic_semaphore_base(ptrdiff_t __count) : __a(__count)
+    {
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void release(ptrdiff_t __update = 1)
+    {
+        if(0 < __a.fetch_add(__update, memory_order_release))
+            ;
+        else if(__update > 1)
+            __a.notify_all();
+        else
+            __a.notify_one();
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void acquire()
+    {
+        auto const __test_fn = [this]() -> bool {
+            auto __old = __a.load(memory_order_relaxed);
+            return (__old != 0) && __a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed);
+        };
+        __cxx_atomic_wait(&__a.__a_, __test_fn);
+    }
+    template <class Rep, class Period>
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_for(chrono::duration<Rep, Period> const& __rel_time)
+    {
+        auto const __test_fn = [this]() -> bool {
+            auto __old = __a.load(memory_order_acquire);
+            while(1) {
+                if (__old == 0)
+                    return false;
+                if(__a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed))
+                    return true;
+            }
+        };
+        return __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy(), __rel_time);
+    }
+};
+
+#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
+
+/*
+
+__platform_semaphore_base a simple wrapper for the OS semaphore type. That
+is, every call is routed to the OS in the most direct manner possible.
+
+*/
+
+class __platform_semaphore_base
+{
+    __libcpp_semaphore_t __semaphore;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __platform_semaphore_base(ptrdiff_t __count) :
+        __semaphore()
+    {
+        __libcpp_semaphore_init(&__semaphore, __count);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    ~__platform_semaphore_base() {
+        __libcpp_semaphore_destroy(&__semaphore);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void release(ptrdiff_t __update)
+    {
+        for(; __update; --__update)
+            __libcpp_semaphore_post(&__semaphore);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void acquire()
+    {
+        __libcpp_semaphore_wait(&__semaphore);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_for(chrono::nanoseconds __rel_time)
+    {
+        return __libcpp_semaphore_wait_timed(&__semaphore, __rel_time);
+    }
+};
+
+template<ptrdiff_t __least_max_value>
+using __semaphore_base =
+    typename conditional<(__least_max_value > 1 && __least_max_value <= _LIBCPP_SEMAPHORE_MAX),
+                         __platform_semaphore_base,
+                         __atomic_semaphore_base>::type;
+
+#else
+
+template<ptrdiff_t __least_max_value>
+using __semaphore_base =
+    __atomic_semaphore_base;
+
+#define _LIBCPP_SEMAPHORE_MAX (numeric_limits<ptrdiff_t>::max())
+
+#endif //_LIBCPP_NO_NATIVE_SEMAPHORES
+
+template<ptrdiff_t __least_max_value = _LIBCPP_SEMAPHORE_MAX>
+class counting_semaphore
+{
+    __semaphore_base<__least_max_value> __semaphore;
+
+public:
+    static constexpr ptrdiff_t max() noexcept {
+        return __least_max_value;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit counting_semaphore(ptrdiff_t __count) : __semaphore(__count) { }
+    ~counting_semaphore() = default;
+
+    counting_semaphore(const counting_semaphore&) = delete;
+    counting_semaphore& operator=(const counting_semaphore&) = delete;
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void release(ptrdiff_t __update = 1)
+    {
+        __semaphore.release(__update);
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void acquire()
+    {
+        __semaphore.acquire();
+    }
+    template<class Rep, class Period>
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_for(chrono::duration<Rep, Period> const& __rel_time)
+    {
+        return __semaphore.try_acquire_for(chrono::duration_cast<chrono::nanoseconds>(__rel_time));
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire()
+    {
+        return try_acquire_for(chrono::nanoseconds::zero());
+    }
+    template <class Clock, class Duration>
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_until(chrono::time_point<Clock, Duration> const& __abs_time)
+    {
+        auto const current = Clock::now();
+        if(current >= __abs_time)
+            return try_acquire();
+        else
+            return try_acquire_for(__abs_time - current);
+    }
+};
+
+using binary_semaphore = counting_semaphore<1>;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 14
+
+_LIBCPP_POP_MACROS
+
+#endif //_LIBCPP_SEMAPHORE