]> git.ipfire.org Git - thirdparty/gcc.git/blobdiff - libstdc++-v3/include/std/thread
Update copyright years.
[thirdparty/gcc.git] / libstdc++-v3 / include / std / thread
index 6ca40cd266a167e3c4aaec09f120f39cc288a650..ad383395ee9fe9413932fcf77bded8fe1db49fa4 100644 (file)
@@ -1,6 +1,6 @@
 // <thread> -*- C++ -*-
 
-// Copyright (C) 2008-2012 Free Software Foundation, Inc.
+// Copyright (C) 2008-2021 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
 # include <bits/c++0x_warning.h>
 #else
 
-#include <chrono>
-#include <functional>
-#include <memory>
-#include <bits/functexcept.h>
-#include <bits/functional_hash.h>
-#include <bits/gthr.h>
+#include <chrono> // std::chrono::*
 
-#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
+#if __cplusplus > 201703L
+# include <compare>    // std::strong_ordering
+# include <stop_token> // std::stop_source, std::stop_token, std::nostopstate
+#endif
+
+#include <bits/std_thread.h> // std::thread, get_id, yield
+
+#ifdef _GLIBCXX_USE_NANOSLEEP
+# include <cerrno>  // errno, EINTR
+# include <time.h>  // nanosleep
+#endif
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -56,154 +61,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    * @{
    */
 
-  /// thread
-  class thread
-  {
-  public:
-    typedef __gthread_t                        native_handle_type;
-    struct _Impl_base;
-    typedef shared_ptr<_Impl_base>     __shared_base_type;
-
-    /// thread::id
-    class id
-    {
-      native_handle_type       _M_thread;
-
-    public:
-      id() noexcept : _M_thread() { }
-
-      explicit
-      id(native_handle_type __id) : _M_thread(__id) { }
-
-    private:
-      friend class thread;
-      friend class hash<thread::id>;
-
-      friend bool
-      operator==(thread::id __x, thread::id __y) noexcept
-      { return __gthread_equal(__x._M_thread, __y._M_thread); }
-
-      friend bool
-      operator<(thread::id __x, thread::id __y) noexcept
-      { return __x._M_thread < __y._M_thread; }
-
-      template<class _CharT, class _Traits>
-       friend basic_ostream<_CharT, _Traits>&
-       operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id);
-    };
-
-    // Simple base type that the templatized, derived class containing
-    // an arbitrary functor can be converted to and called.
-    struct _Impl_base
-    {
-      __shared_base_type       _M_this_ptr;
-
-      inline virtual ~_Impl_base();
-
-      virtual void _M_run() = 0;
-    };
-
-    template<typename _Callable>
-      struct _Impl : public _Impl_base
-      {
-       _Callable               _M_func;
-
-       _Impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f))
-       { }
-
-       void
-       _M_run() { _M_func(); }
-      };
-
-  private:
-    id                         _M_id;
-
-  public:
-    thread() noexcept = default;
-    // _GLIBCXX_RESOLVE_LIB_DEFECTS
-    // 2097.  packaged_task constructors should be constrained
-    thread(thread&) = delete;
-    thread(const thread&) = delete;
-
-    thread(thread&& __t) noexcept
-    { swap(__t); }
-
-    template<typename _Callable, typename... _Args>
-      explicit 
-      thread(_Callable&& __f, _Args&&... __args)
-      {
-        _M_start_thread(_M_make_routine(std::__bind_simple(
-                std::forward<_Callable>(__f),
-                std::forward<_Args>(__args)...)));
-      }
-
-    ~thread()
-    {
-      if (joinable())
-       std::terminate();
-    }
-
-    thread& operator=(const thread&) = delete;
-
-    thread& operator=(thread&& __t) noexcept
-    {
-      if (joinable())
-       std::terminate();
-      swap(__t);
-      return *this;
-    }
-
-    void
-    swap(thread& __t) noexcept
-    { std::swap(_M_id, __t._M_id); }
-
-    bool
-    joinable() const noexcept
-    { return !(_M_id == id()); }
-
-    void
-    join();
-
-    void
-    detach();
-
-    thread::id
-    get_id() const noexcept
-    { return _M_id; }
-
-    /** @pre thread is joinable
-     */
-    native_handle_type
-    native_handle()
-    { return _M_id._M_thread; }
-
-    // Returns a value that hints at the number of hardware thread contexts.
-    static unsigned int
-    hardware_concurrency() noexcept;
-
-  private:
-    void
-    _M_start_thread(__shared_base_type);
-
-    template<typename _Callable>
-      shared_ptr<_Impl<_Callable>>
-      _M_make_routine(_Callable&& __f)
-      {
-       // Create and allocate full data structure, not base.
-       return std::make_shared<_Impl<_Callable>>(std::forward<_Callable>(__f));
-      }
-  };
-
-  inline thread::_Impl_base::~_Impl_base() = default;
-
-  inline void
-  swap(thread& __x, thread& __y) noexcept
-  { __x.swap(__y); }
+  // std::thread is defined in <bits/std_thread.h>
 
+#if __cpp_lib_three_way_comparison
+  inline strong_ordering
+  operator<=>(thread::id __x, thread::id __y) noexcept
+  { return __x._M_thread <=> __y._M_thread; }
+#else
   inline bool
   operator!=(thread::id __x, thread::id __y) noexcept
   { return !(__x == __y); }
 
+  inline bool
+  operator<(thread::id __x, thread::id __y) noexcept
+  {
+    // Pthreads doesn't define any way to do this, so we just have to
+    // assume native_handle_type is LessThanComparable.
+    return __x._M_thread < __y._M_thread;
+  }
+
   inline bool
   operator<=(thread::id __x, thread::id __y) noexcept
   { return !(__y < __x); }
@@ -215,17 +91,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   inline bool
   operator>=(thread::id __x, thread::id __y) noexcept
   { return !(__x < __y); }
-
-  // DR 889.
-  /// std::hash specialization for thread::id.
-  template<>
-    struct hash<thread::id>
-    : public __hash_base<size_t, thread::id>
-    {
-      size_t
-      operator()(const thread::id& __id) const noexcept
-      { return std::_Hash_impl::hash(__id._M_thread); }
-    };
+#endif // __cpp_lib_three_way_comparison
 
   template<class _CharT, class _Traits>
     inline basic_ostream<_CharT, _Traits>&
@@ -237,66 +103,203 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        return __out << __id._M_thread;
     }
 
-_GLIBCXX_END_NAMESPACE_VERSION
-
   /** @namespace std::this_thread
-   *  @brief ISO C++ 2011 entities sub-namespace for thread.
-   *  30.3.2 Namespace this_thread.
+   *  @brief ISO C++ 2011 namespace for interacting with the current thread
+   *
+   *  C++11 30.3.2 [thread.thread.this] Namespace this_thread.
    */
   namespace this_thread
   {
-  _GLIBCXX_BEGIN_NAMESPACE_VERSION
-
-    /// get_id
-    inline thread::id
-    get_id() noexcept { return thread::id(__gthread_self()); }
-
-    /// yield
-    inline void
-    yield() noexcept
-    {
-#ifdef _GLIBCXX_USE_SCHED_YIELD
-      __gthread_yield();
-#endif
-    }
+#ifndef _GLIBCXX_NO_SLEEP
 
+#ifndef _GLIBCXX_USE_NANOSLEEP
     void
     __sleep_for(chrono::seconds, chrono::nanoseconds);
+#endif
 
-    /// sleep_for
+    /// this_thread::sleep_for
     template<typename _Rep, typename _Period>
       inline void
       sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
       {
+       if (__rtime <= __rtime.zero())
+         return;
        auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
        auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
 #ifdef _GLIBCXX_USE_NANOSLEEP
-       __gthread_time_t __ts =
+       struct ::timespec __ts =
          {
            static_cast<std::time_t>(__s.count()),
            static_cast<long>(__ns.count())
          };
-       ::nanosleep(&__ts, 0);
+       while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR)
+         { }
 #else
        __sleep_for(__s, __ns);
 #endif
       }
 
-    /// sleep_until
+    /// this_thread::sleep_until
     template<typename _Clock, typename _Duration>
       inline void
       sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
-      { sleep_for(__atime - _Clock::now()); }
+      {
+#if __cplusplus > 201703L
+       static_assert(chrono::is_clock_v<_Clock>);
+#endif
+       auto __now = _Clock::now();
+       if (_Clock::is_steady)
+         {
+           if (__now < __atime)
+             sleep_for(__atime - __now);
+           return;
+         }
+       while (__now < __atime)
+         {
+           sleep_for(__atime - __now);
+           __now = _Clock::now();
+         }
+      }
+  } // namespace this_thread
+#endif // ! NO_SLEEP
 
-  _GLIBCXX_END_NAMESPACE_VERSION
-  }
+#ifdef __cpp_lib_jthread
 
-  // @} group threads
+  /// A thread that can be requested to stop and automatically joined.
+  class jthread
+  {
+  public:
+    using id = thread::id;
+    using native_handle_type = thread::native_handle_type;
 
-} // namespace
+    jthread() noexcept
+    : _M_stop_source{nostopstate}
+    { }
+
+    template<typename _Callable, typename... _Args,
+            typename = enable_if_t<!is_same_v<remove_cvref_t<_Callable>,
+                                              jthread>>>
+      explicit
+      jthread(_Callable&& __f, _Args&&... __args)
+      : _M_thread{_S_create(_M_stop_source, std::forward<_Callable>(__f),
+                           std::forward<_Args>(__args)...)}
+      { }
 
-#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
+    jthread(const jthread&) = delete;
+    jthread(jthread&&) noexcept = default;
 
-#endif // C++11
+    ~jthread()
+    {
+      if (joinable())
+        {
+          request_stop();
+          join();
+        }
+    }
 
+    jthread&
+    operator=(const jthread&) = delete;
+
+    jthread&
+    operator=(jthread&& __other) noexcept
+    {
+      std::jthread(std::move(__other)).swap(*this);
+      return *this;
+    }
+
+    void
+    swap(jthread& __other) noexcept
+    {
+      std::swap(_M_stop_source, __other._M_stop_source);
+      std::swap(_M_thread, __other._M_thread);
+    }
+
+    [[nodiscard]] bool
+    joinable() const noexcept
+    {
+      return _M_thread.joinable();
+    }
+
+    void
+    join()
+    {
+      _M_thread.join();
+    }
+
+    void
+    detach()
+    {
+      _M_thread.detach();
+    }
+
+    [[nodiscard]] id
+    get_id() const noexcept
+    {
+      return _M_thread.get_id();
+    }
+
+    [[nodiscard]] native_handle_type
+    native_handle()
+    {
+      return _M_thread.native_handle();
+    }
+
+    [[nodiscard]] static unsigned
+    hardware_concurrency() noexcept
+    {
+      return thread::hardware_concurrency();
+    }
+
+    [[nodiscard]] stop_source
+    get_stop_source() noexcept
+    {
+      return _M_stop_source;
+    }
+
+    [[nodiscard]] stop_token
+    get_stop_token() const noexcept
+    {
+      return _M_stop_source.get_token();
+    }
+
+    bool request_stop() noexcept
+    {
+      return _M_stop_source.request_stop();
+    }
+
+    friend void swap(jthread& __lhs, jthread& __rhs) noexcept
+    {
+      __lhs.swap(__rhs);
+    }
+
+  private:
+    template<typename _Callable, typename... _Args>
+      static thread
+      _S_create(stop_source& __ssrc, _Callable&& __f, _Args&&... __args)
+      {
+       if constexpr(is_invocable_v<decay_t<_Callable>, stop_token,
+                                   decay_t<_Args>...>)
+         return thread{std::forward<_Callable>(__f), __ssrc.get_token(),
+                       std::forward<_Args>(__args)...};
+       else
+         {
+           static_assert(is_invocable_v<decay_t<_Callable>,
+                                        decay_t<_Args>...>,
+                         "std::thread arguments must be invocable after"
+                         " conversion to rvalues");
+           return thread{std::forward<_Callable>(__f),
+                         std::forward<_Args>(__args)...};
+         }
+      }
+
+    stop_source _M_stop_source;
+    thread _M_thread;
+  };
+#endif // __cpp_lib_jthread
+
+  // @} group threads
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11
 #endif // _GLIBCXX_THREAD