c%2B%2B/11.2.0/coroutine

// <coroutine> -*- C++ -*-

// Copyright (C) 2019-2021 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
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file include/coroutine
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_COROUTINE
#define _GLIBCXX_COROUTINE 1

#pragma GCC system_header

// It is very likely that earlier versions would work, but they are untested.
#if __cplusplus >= 201402L

#include <bits/c++config.h>

/**
 * @defgroup coroutines Coroutines
 *
 * Components for supporting coroutine implementations.
 */

#if __cplusplus > 201703L && __cpp_impl_three_way_comparison >= 201907L
#  include <compare>
#  define _COROUTINES_USE_SPACESHIP 1
#else
#  include <bits/stl_function.h> // for std::less
#  define _COROUTINES_USE_SPACESHIP 0
#endif

namespace std _GLIBCXX_VISIBILITY (default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#if __cpp_impl_coroutine

#define __cpp_lib_coroutine 201902L

  inline namespace __n4861 {

  // 17.12.2 coroutine traits
  /// [coroutine.traits]
  /// [coroutine.traits.primary]
  /// If _Result::promise_type is valid and denotes a type then the traits
  /// have a single publicly accessible member, otherwise they are empty.
  template <typename _Result, typename = void>
   struct __coroutine_traits_impl {};

  template <typename _Result>
    struct __coroutine_traits_impl<_Result,
                                    __void_t<typename _Result::promise_type>>
    {
      using promise_type = typename _Result::promise_type;
    };

  template <typename _Result, typename...>
    struct coroutine_traits : __coroutine_traits_impl<_Result> {};

  // 17.12.3 Class template coroutine_handle
  /// [coroutine.handle]
  template <typename _Promise = void>
    struct coroutine_handle;

  template <> struct
    coroutine_handle<void>
    {
    public:
      // [coroutine.handle.con], construct/reset
      constexpr coroutine_handle() noexcept : _M_fr_ptr(0) {}

      constexpr coroutine_handle(std::nullptr_t __h) noexcept
        : _M_fr_ptr(__h)
      {}

      coroutine_handle& operator=(std::nullptr_t) noexcept
      {
        _M_fr_ptr = nullptr;
        return *this;
      }

    public:
      // [coroutine.handle.export.import], export/import
      constexpr void* address() const noexcept { return _M_fr_ptr; }

      constexpr static coroutine_handle from_address(void* __a) noexcept
      {
        coroutine_handle __self;
        __self._M_fr_ptr = __a;
        return __self;
      }

    public:
      // [coroutine.handle.observers], observers
      constexpr explicit operator bool() const noexcept
      {
        return bool(_M_fr_ptr);
      }

      bool done() const noexcept { return __builtin_coro_done(_M_fr_ptr); }

      // [coroutine.handle.resumption], resumption
      void operator()() const { resume(); }

      void resume() const { __builtin_coro_resume(_M_fr_ptr); }

      void destroy() const { __builtin_coro_destroy(_M_fr_ptr); }

    protected:
      void* _M_fr_ptr;
  };

  // [coroutine.handle.compare], comparison operators

  constexpr bool
  operator==(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return __a.address() == __b.address();
  }

#if _COROUTINES_USE_SPACESHIP
  constexpr strong_ordering
  operator<=>(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return std::compare_three_way()(__a.address(), __b.address());
  }
#else
  // These are to enable operation with std=c++14,17.
  constexpr bool
  operator!=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return !(__a == __b);
  }

  constexpr bool
  operator<(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return less<void*>()(__a.address(), __b.address());
  }

  constexpr bool
  operator>(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return __b < __a;
  }

  constexpr bool
  operator<=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return !(__a > __b);
  }

  constexpr bool
  operator>=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
  {
    return !(__a < __b);
  }
#endif

  template <typename _Promise>
    struct coroutine_handle
    {
      // [coroutine.handle.con], construct/reset

      constexpr coroutine_handle() noexcept { }

      constexpr coroutine_handle(nullptr_t) noexcept { }

      static coroutine_handle
      from_promise(_Promise& __p)
      {
        coroutine_handle __self;
        __self._M_fr_ptr
          = __builtin_coro_promise((char*) &__p, __alignof(_Promise), true);
        return __self;
      }

      coroutine_handle& operator=(nullptr_t) noexcept
      {
        _M_fr_ptr = nullptr;
        return *this;
      }

      // [coroutine.handle.export.import], export/import

      constexpr void* address() const noexcept { return _M_fr_ptr; }

      constexpr static coroutine_handle from_address(void* __a) noexcept
      {
        coroutine_handle __self;
        __self._M_fr_ptr = __a;
        return __self;
      }

      // [coroutine.handle.conv], conversion
      constexpr operator coroutine_handle<>() const noexcept
      { return coroutine_handle<>::from_address(address()); }

      // [coroutine.handle.observers], observers
      constexpr explicit operator bool() const noexcept
      {
        return bool(_M_fr_ptr);
      }

      bool done() const noexcept { return __builtin_coro_done(_M_fr_ptr); }

      // [coroutine.handle.resumption], resumption
      void operator()() const { resume(); }

      void resume() const { __builtin_coro_resume(_M_fr_ptr); }

      void destroy() const { __builtin_coro_destroy(_M_fr_ptr); }

      // [coroutine.handle.promise], promise access
      _Promise& promise() const
      {
        void* __t
          = __builtin_coro_promise (_M_fr_ptr, __alignof(_Promise), false);
        return *static_cast<_Promise*>(__t);
      }

    private:
      void* _M_fr_ptr = nullptr;
    };

  /// [coroutine.noop]
  struct noop_coroutine_promise
  {
  };

  // 17.12.4.1 Class noop_coroutine_promise
  /// [coroutine.promise.noop]
  template <>
    struct coroutine_handle<noop_coroutine_promise>
    {
      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 3460. Unimplementable noop_coroutine_handle guarantees
      // [coroutine.handle.noop.conv], conversion
      constexpr operator coroutine_handle<>() const noexcept
      { return coroutine_handle<>::from_address(address()); }

      // [coroutine.handle.noop.observers], observers
      constexpr explicit operator bool() const noexcept { return true; }

      constexpr bool done() const noexcept { return false; }

      // [coroutine.handle.noop.resumption], resumption
      void operator()() const noexcept {}

      void resume() const noexcept {}

      void destroy() const noexcept {}

      // [coroutine.handle.noop.promise], promise access
      noop_coroutine_promise& promise() const noexcept
      { return _S_fr.__p; }

      // [coroutine.handle.noop.address], address
      constexpr void* address() const noexcept { return _M_fr_ptr; }

    private:
      friend coroutine_handle noop_coroutine() noexcept;

      struct __frame
      {
        static void __dummy_resume_destroy() { }

        void (*__r)() = __dummy_resume_destroy;
        void (*__d)() = __dummy_resume_destroy;
        struct noop_coroutine_promise __p;
      };

      static __frame _S_fr;

      explicit coroutine_handle() noexcept = default;

      void* _M_fr_ptr = &_S_fr;
    };

  using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;

  inline noop_coroutine_handle::__frame
  noop_coroutine_handle::_S_fr{};

  inline noop_coroutine_handle noop_coroutine() noexcept
  {
    return noop_coroutine_handle();
  }

  // 17.12.5 Trivial awaitables
  /// [coroutine.trivial.awaitables]
  struct suspend_always
  {
    constexpr bool await_ready() const noexcept { return false; }

    constexpr void await_suspend(coroutine_handle<>) const noexcept {}

    constexpr void await_resume() const noexcept {}
  };

  struct suspend_never
  {
    constexpr bool await_ready() const noexcept { return true; }

    constexpr void await_suspend(coroutine_handle<>) const noexcept {}

    constexpr void await_resume() const noexcept {}
  };

  } // namespace __n4861

#else
#error "the coroutine header requires -fcoroutines"
#endif

  _GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // C++14 (we are allowing use from at least this)

#endif // _GLIBCXX_COROUTINE
Revision:	1166
Committed:	Tue Oct 26 14:22:36 2021 UTC (4 years ago) by rossy
File size:	9156 byte(s)
Log Message:	Daodan: Replace MinGW build env with an up-to-date MSYS2 env
#	Content
1	// <coroutine> -- C++ --
2
3	// Copyright (C) 2019-2021 Free Software Foundation, Inc.
4	//
5	// This file is part of the GNU ISO C++ Library. This library is free
6	// software; you can redistribute it and/or modify it under the
7	// terms of the GNU General Public License as published by the
8	// Free Software Foundation; either version 3, or (at your option)
9	// any later version.
10
11	// This library is distributed in the hope that it will be useful,
12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	// GNU General Public License for more details.
15
16	// Under Section 7 of GPL version 3, you are granted additional
17	// permissions described in the GCC Runtime Library Exception, version
18	// 3.1, as published by the Free Software Foundation.
19
20	// You should have received a copy of the GNU General Public License and
21	// a copy of the GCC Runtime Library Exception along with this program;
22	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23	// <http://www.gnu.org/licenses/>.
24
25	/** @file include/coroutine
26	* This is a Standard C++ Library header.
27	*/
28
29	#ifndef _GLIBCXX_COROUTINE
30	#define _GLIBCXX_COROUTINE 1
31
32	#pragma GCC system_header
33
34	// It is very likely that earlier versions would work, but they are untested.
35	#if __cplusplus >= 201402L
36
37	#include <bits/c++config.h>
38
39	/**
40	* @defgroup coroutines Coroutines
41	*
42	* Components for supporting coroutine implementations.
43	*/
44
45	#if __cplusplus > 201703L && __cpp_impl_three_way_comparison >= 201907L
46	# include <compare>
47	# define _COROUTINES_USE_SPACESHIP 1
48	#else
49	# include <bits/stl_function.h> // for std::less
50	# define _COROUTINES_USE_SPACESHIP 0
51	#endif
52
53	namespace std _GLIBCXX_VISIBILITY (default)
54	{
55	_GLIBCXX_BEGIN_NAMESPACE_VERSION
56
57	#if __cpp_impl_coroutine
58
59	#define __cpp_lib_coroutine 201902L
60
61	inline namespace __n4861 {
62
63	// 17.12.2 coroutine traits
64	/// [coroutine.traits]
65	/// [coroutine.traits.primary]
66	/// If _Result::promise_type is valid and denotes a type then the traits
67	/// have a single publicly accessible member, otherwise they are empty.
68	template <typename _Result, typename = void>
69	struct __coroutine_traits_impl {};
70
71	template <typename _Result>
72	struct __coroutine_traits_impl<_Result,
73	__void_t<typename _Result::promise_type>>
74	{
75	using promise_type = typename _Result::promise_type;
76	};
77
78	template <typename _Result, typename...>
79	struct coroutine_traits : __coroutine_traits_impl<_Result> {};
80
81	// 17.12.3 Class template coroutine_handle
82	/// [coroutine.handle]
83	template <typename _Promise = void>
84	struct coroutine_handle;
85
86	template <> struct
87	coroutine_handle<void>
88	{
89	public:
90	// [coroutine.handle.con], construct/reset
91	constexpr coroutine_handle() noexcept : _M_fr_ptr(0) {}
92
93	constexpr coroutine_handle(std::nullptr_t __h) noexcept
94	: _M_fr_ptr(__h)
95	{}
96
97	coroutine_handle& operator=(std::nullptr_t) noexcept
98	{
99	_M_fr_ptr = nullptr;
100	return *this;
101	}
102
103	public:
104	// [coroutine.handle.export.import], export/import
105	constexpr void* address() const noexcept { return _M_fr_ptr; }
106
107	constexpr static coroutine_handle from_address(void* __a) noexcept
108	{
109	coroutine_handle __self;
110	__self._M_fr_ptr = __a;
111	return __self;
112	}
113
114	public:
115	// [coroutine.handle.observers], observers
116	constexpr explicit operator bool() const noexcept
117	{
118	return bool(_M_fr_ptr);
119	}
120
121	bool done() const noexcept { return __builtin_coro_done(_M_fr_ptr); }
122
123	// [coroutine.handle.resumption], resumption
124	void operator()() const { resume(); }
125
126	void resume() const { __builtin_coro_resume(_M_fr_ptr); }
127
128	void destroy() const { __builtin_coro_destroy(_M_fr_ptr); }
129
130	protected:
131	void* _M_fr_ptr;
132	};
133
134	// [coroutine.handle.compare], comparison operators
135
136	constexpr bool
137	operator==(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
138	{
139	return __a.address() == __b.address();
140	}
141
142	#if _COROUTINES_USE_SPACESHIP
143	constexpr strong_ordering
144	operator<=>(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
145	{
146	return std::compare_three_way()(__a.address(), __b.address());
147	}
148	#else
149	// These are to enable operation with std=c++14,17.
150	constexpr bool
151	operator!=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
152	{
153	return !(__a == __b);
154	}
155
156	constexpr bool
157	operator<(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
158	{
159	return less<void*>()(__a.address(), __b.address());
160	}
161
162	constexpr bool
163	operator>(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
164	{
165	return __b < __a;
166	}
167
168	constexpr bool
169	operator<=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
170	{
171	return !(__a > __b);
172	}
173
174	constexpr bool
175	operator>=(coroutine_handle<> __a, coroutine_handle<> __b) noexcept
176	{
177	return !(__a < __b);
178	}
179	#endif
180
181	template <typename _Promise>
182	struct coroutine_handle
183	{
184	// [coroutine.handle.con], construct/reset
185
186	constexpr coroutine_handle() noexcept { }
187
188	constexpr coroutine_handle(nullptr_t) noexcept { }
189
190	static coroutine_handle
191	from_promise(_Promise& __p)
192	{
193	coroutine_handle __self;
194	__self._M_fr_ptr
195	= __builtin_coro_promise((char*) &__p, __alignof(_Promise), true);
196	return __self;
197	}
198
199	coroutine_handle& operator=(nullptr_t) noexcept
200	{
201	_M_fr_ptr = nullptr;
202	return *this;
203	}
204
205	// [coroutine.handle.export.import], export/import
206
207	constexpr void* address() const noexcept { return _M_fr_ptr; }
208
209	constexpr static coroutine_handle from_address(void* __a) noexcept
210	{
211	coroutine_handle __self;
212	__self._M_fr_ptr = __a;
213	return __self;
214	}
215
216	// [coroutine.handle.conv], conversion
217	constexpr operator coroutine_handle<>() const noexcept
218	{ return coroutine_handle<>::from_address(address()); }
219
220	// [coroutine.handle.observers], observers
221	constexpr explicit operator bool() const noexcept
222	{
223	return bool(_M_fr_ptr);
224	}
225
226	bool done() const noexcept { return __builtin_coro_done(_M_fr_ptr); }
227
228	// [coroutine.handle.resumption], resumption
229	void operator()() const { resume(); }
230
231	void resume() const { __builtin_coro_resume(_M_fr_ptr); }
232
233	void destroy() const { __builtin_coro_destroy(_M_fr_ptr); }
234
235	// [coroutine.handle.promise], promise access
236	_Promise& promise() const
237	{
238	void* __t
239	= __builtin_coro_promise (_M_fr_ptr, __alignof(_Promise), false);
240	return static_cast<_Promise>(__t);
241	}
242
243	private:
244	void* _M_fr_ptr = nullptr;
245	};
246
247	/// [coroutine.noop]
248	struct noop_coroutine_promise
249	{
250	};
251
252	// 17.12.4.1 Class noop_coroutine_promise
253	/// [coroutine.promise.noop]
254	template <>
255	struct coroutine_handle<noop_coroutine_promise>
256	{
257	// _GLIBCXX_RESOLVE_LIB_DEFECTS
258	// 3460. Unimplementable noop_coroutine_handle guarantees
259	// [coroutine.handle.noop.conv], conversion
260	constexpr operator coroutine_handle<>() const noexcept
261	{ return coroutine_handle<>::from_address(address()); }
262
263	// [coroutine.handle.noop.observers], observers
264	constexpr explicit operator bool() const noexcept { return true; }
265
266	constexpr bool done() const noexcept { return false; }
267
268	// [coroutine.handle.noop.resumption], resumption
269	void operator()() const noexcept {}
270
271	void resume() const noexcept {}
272
273	void destroy() const noexcept {}
274
275	// [coroutine.handle.noop.promise], promise access
276	noop_coroutine_promise& promise() const noexcept
277	{ return _S_fr.__p; }
278
279	// [coroutine.handle.noop.address], address
280	constexpr void* address() const noexcept { return _M_fr_ptr; }
281
282	private:
283	friend coroutine_handle noop_coroutine() noexcept;
284
285	struct __frame
286	{
287	static void __dummy_resume_destroy() { }
288
289	void (*__r)() = __dummy_resume_destroy;
290	void (*__d)() = __dummy_resume_destroy;
291	struct noop_coroutine_promise __p;
292	};
293
294	static __frame _S_fr;
295
296	explicit coroutine_handle() noexcept = default;
297
298	void* _M_fr_ptr = &_S_fr;
299	};
300
301	using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
302
303	inline noop_coroutine_handle::__frame
304	noop_coroutine_handle::_S_fr{};
305
306	inline noop_coroutine_handle noop_coroutine() noexcept
307	{
308	return noop_coroutine_handle();
309	}
310
311	// 17.12.5 Trivial awaitables
312	/// [coroutine.trivial.awaitables]
313	struct suspend_always
314	{
315	constexpr bool await_ready() const noexcept { return false; }
316
317	constexpr void await_suspend(coroutine_handle<>) const noexcept {}
318
319	constexpr void await_resume() const noexcept {}
320	};
321
322	struct suspend_never
323	{
324	constexpr bool await_ready() const noexcept { return true; }
325
326	constexpr void await_suspend(coroutine_handle<>) const noexcept {}
327
328	constexpr void await_resume() const noexcept {}
329	};
330
331	} // namespace __n4861
332
333	#else
334	#error "the coroutine header requires -fcoroutines"
335	#endif
336
337	_GLIBCXX_END_NAMESPACE_VERSION
338	} // namespace std
339
340	#endif // C++14 (we are allowing use from at least this)
341
342	#endif // _GLIBCXX_COROUTINE