1// -*- C++ -*-
2//===--------------------------- thread -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_THREAD
12#define _LIBCPP_THREAD
13
14/*
15
16    thread synopsis
17
18#define __STDCPP_THREADS__ __cplusplus
19
20namespace std
21{
22
23class thread
24{
25public:
26    class id;
27    typedef pthread_t native_handle_type;
28
29    thread() noexcept;
30    template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
31    ~thread();
32
33    thread(const thread&) = delete;
34    thread(thread&& t) noexcept;
35
36    thread& operator=(const thread&) = delete;
37    thread& operator=(thread&& t) noexcept;
38
39    void swap(thread& t) noexcept;
40
41    bool joinable() const noexcept;
42    void join();
43    void detach();
44    id get_id() const noexcept;
45    native_handle_type native_handle();
46
47    static unsigned hardware_concurrency() noexcept;
48};
49
50void swap(thread& x, thread& y) noexcept;
51
52class thread::id
53{
54public:
55    id() noexcept;
56};
57
58bool operator==(thread::id x, thread::id y) noexcept;
59bool operator!=(thread::id x, thread::id y) noexcept;
60bool operator< (thread::id x, thread::id y) noexcept;
61bool operator<=(thread::id x, thread::id y) noexcept;
62bool operator> (thread::id x, thread::id y) noexcept;
63bool operator>=(thread::id x, thread::id y) noexcept;
64
65template<class charT, class traits>
66basic_ostream<charT, traits>&
67operator<<(basic_ostream<charT, traits>& out, thread::id id);
68
69namespace this_thread
70{
71
72thread::id get_id() noexcept;
73
74void yield() noexcept;
75
76template <class Clock, class Duration>
77void sleep_until(const chrono::time_point<Clock, Duration>& abs_time);
78
79template <class Rep, class Period>
80void sleep_for(const chrono::duration<Rep, Period>& rel_time);
81
82}  // this_thread
83
84}  // std
85
86*/
87
88#include <__config>
89#include <iosfwd>
90#include <__functional_base>
91#include <type_traits>
92#include <cstddef>
93#include <functional>
94#include <memory>
95#include <system_error>
96#include <chrono>
97#include <__mutex_base>
98#ifndef _LIBCPP_CXX03_LANG
99#include <tuple>
100#endif
101#include <__threading_support>
102#include <__debug>
103
104#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
105#pragma GCC system_header
106#endif
107
108_LIBCPP_PUSH_MACROS
109#include <__undef_macros>
110
111#define __STDCPP_THREADS__ __cplusplus
112
113#ifdef _LIBCPP_HAS_NO_THREADS
114#error <thread> is not supported on this single threaded system
115#else // !_LIBCPP_HAS_NO_THREADS
116
117_LIBCPP_BEGIN_NAMESPACE_STD
118
119template <class _Tp> class __thread_specific_ptr;
120class _LIBCPP_TYPE_VIS __thread_struct;
121class _LIBCPP_HIDDEN __thread_struct_imp;
122class __assoc_sub_state;
123
124_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
125
126class _LIBCPP_TYPE_VIS __thread_struct
127{
128    __thread_struct_imp* __p_;
129
130    __thread_struct(const __thread_struct&);
131    __thread_struct& operator=(const __thread_struct&);
132public:
133    __thread_struct();
134    ~__thread_struct();
135
136    void notify_all_at_thread_exit(condition_variable*, mutex*);
137    void __make_ready_at_thread_exit(__assoc_sub_state*);
138};
139
140template <class _Tp>
141class __thread_specific_ptr
142{
143    __libcpp_tls_key __key_;
144
145     // Only __thread_local_data() may construct a __thread_specific_ptr
146     // and only with _Tp == __thread_struct.
147    static_assert((is_same<_Tp, __thread_struct>::value), "");
148    __thread_specific_ptr();
149    friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
150
151    __thread_specific_ptr(const __thread_specific_ptr&);
152    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
153
154    static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
155
156public:
157    typedef _Tp* pointer;
158
159    ~__thread_specific_ptr();
160
161    _LIBCPP_INLINE_VISIBILITY
162    pointer get() const {return static_cast<_Tp*>(__libcpp_tls_get(__key_));}
163    _LIBCPP_INLINE_VISIBILITY
164    pointer operator*() const {return *get();}
165    _LIBCPP_INLINE_VISIBILITY
166    pointer operator->() const {return get();}
167    void set_pointer(pointer __p);
168};
169
170template <class _Tp>
171void _LIBCPP_TLS_DESTRUCTOR_CC
172__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
173{
174    delete static_cast<pointer>(__p);
175}
176
177template <class _Tp>
178__thread_specific_ptr<_Tp>::__thread_specific_ptr()
179{
180  int __ec =
181      __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
182  if (__ec)
183    __throw_system_error(__ec, "__thread_specific_ptr construction failed");
184}
185
186template <class _Tp>
187__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
188{
189    // __thread_specific_ptr is only created with a static storage duration
190    // so this destructor is only invoked during program termination. Invoking
191    // pthread_key_delete(__key_) may prevent other threads from deleting their
192    // thread local data. For this reason we leak the key.
193}
194
195template <class _Tp>
196void
197__thread_specific_ptr<_Tp>::set_pointer(pointer __p)
198{
199    _LIBCPP_ASSERT(get() == nullptr,
200                   "Attempting to overwrite thread local data");
201    __libcpp_tls_set(__key_, __p);
202}
203
204class _LIBCPP_TYPE_VIS thread;
205class _LIBCPP_TYPE_VIS __thread_id;
206
207namespace this_thread
208{
209
210_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
211
212}  // this_thread
213
214template<> struct hash<__thread_id>;
215
216class _LIBCPP_TEMPLATE_VIS __thread_id
217{
218    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
219    // NULL is the no-thread value on Darwin.  Someone needs to check
220    // on other platforms.  We assume 0 works everywhere for now.
221    __libcpp_thread_id __id_;
222
223public:
224    _LIBCPP_INLINE_VISIBILITY
225    __thread_id() _NOEXCEPT : __id_(0) {}
226
227    friend _LIBCPP_INLINE_VISIBILITY
228        bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
229        {return __libcpp_thread_id_equal(__x.__id_, __y.__id_);}
230    friend _LIBCPP_INLINE_VISIBILITY
231        bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
232        {return !(__x == __y);}
233    friend _LIBCPP_INLINE_VISIBILITY
234        bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
235        {return  __libcpp_thread_id_less(__x.__id_, __y.__id_);}
236    friend _LIBCPP_INLINE_VISIBILITY
237        bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
238        {return !(__y < __x);}
239    friend _LIBCPP_INLINE_VISIBILITY
240        bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
241        {return   __y < __x ;}
242    friend _LIBCPP_INLINE_VISIBILITY
243        bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
244        {return !(__x < __y);}
245
246    template<class _CharT, class _Traits>
247    friend
248    _LIBCPP_INLINE_VISIBILITY
249    basic_ostream<_CharT, _Traits>&
250    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
251        {return __os << __id.__id_;}
252
253private:
254    _LIBCPP_INLINE_VISIBILITY
255    __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
256
257    friend __thread_id this_thread::get_id() _NOEXCEPT;
258    friend class _LIBCPP_TYPE_VIS thread;
259    friend struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>;
260};
261
262template<>
263struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>
264    : public unary_function<__thread_id, size_t>
265{
266    _LIBCPP_INLINE_VISIBILITY
267    size_t operator()(__thread_id __v) const _NOEXCEPT
268    {
269        return hash<__libcpp_thread_id>()(__v.__id_);
270    }
271};
272
273namespace this_thread
274{
275
276inline _LIBCPP_INLINE_VISIBILITY
277__thread_id
278get_id() _NOEXCEPT
279{
280    return __libcpp_thread_get_current_id();
281}
282
283}  // this_thread
284
285class _LIBCPP_TYPE_VIS thread
286{
287    __libcpp_thread_t __t_;
288
289    thread(const thread&);
290    thread& operator=(const thread&);
291public:
292    typedef __thread_id id;
293    typedef __libcpp_thread_t native_handle_type;
294
295    _LIBCPP_INLINE_VISIBILITY
296    thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
297#ifndef _LIBCPP_CXX03_LANG
298    template <class _Fp, class ..._Args,
299              class = typename enable_if
300              <
301                   !is_same<typename decay<_Fp>::type, thread>::value
302              >::type
303             >
304        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
305        explicit thread(_Fp&& __f, _Args&&... __args);
306#else  // _LIBCPP_CXX03_LANG
307    template <class _Fp>
308    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
309    explicit thread(_Fp __f);
310#endif
311    ~thread();
312
313#ifndef _LIBCPP_CXX03_LANG
314    _LIBCPP_INLINE_VISIBILITY
315    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = _LIBCPP_NULL_THREAD;}
316    _LIBCPP_INLINE_VISIBILITY
317    thread& operator=(thread&& __t) _NOEXCEPT;
318#endif  // _LIBCPP_CXX03_LANG
319
320    _LIBCPP_INLINE_VISIBILITY
321    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
322
323    _LIBCPP_INLINE_VISIBILITY
324    bool joinable() const _NOEXCEPT {return !__libcpp_thread_isnull(&__t_);}
325    void join();
326    void detach();
327    _LIBCPP_INLINE_VISIBILITY
328    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
329    _LIBCPP_INLINE_VISIBILITY
330    native_handle_type native_handle() _NOEXCEPT {return __t_;}
331
332    static unsigned hardware_concurrency() _NOEXCEPT;
333};
334
335#ifndef _LIBCPP_CXX03_LANG
336
337template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
338inline _LIBCPP_INLINE_VISIBILITY
339void
340__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
341{
342    __invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
343}
344
345template <class _Fp>
346void* __thread_proxy(void* __vp)
347{
348    // _Fp = std::tuple< unique_ptr<__thread_struct>, Functor, Args...>
349    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
350    __thread_local_data().set_pointer(_VSTD::get<0>(*__p).release());
351    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
352    __thread_execute(*__p, _Index());
353    return nullptr;
354}
355
356template <class _Fp, class ..._Args,
357          class
358         >
359thread::thread(_Fp&& __f, _Args&&... __args)
360{
361    typedef unique_ptr<__thread_struct> _TSPtr;
362    _TSPtr __tsp(new __thread_struct);
363    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
364    _VSTD::unique_ptr<_Gp> __p(
365            new _Gp(std::move(__tsp),
366                    __decay_copy(_VSTD::forward<_Fp>(__f)),
367                    __decay_copy(_VSTD::forward<_Args>(__args))...));
368    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
369    if (__ec == 0)
370        __p.release();
371    else
372        __throw_system_error(__ec, "thread constructor failed");
373}
374
375inline
376thread&
377thread::operator=(thread&& __t) _NOEXCEPT
378{
379    if (!__libcpp_thread_isnull(&__t_))
380        terminate();
381    __t_ = __t.__t_;
382    __t.__t_ = _LIBCPP_NULL_THREAD;
383    return *this;
384}
385
386#else  // _LIBCPP_CXX03_LANG
387
388template <class _Fp>
389struct __thread_invoke_pair {
390    // This type is used to pass memory for thread local storage and a functor
391    // to a newly created thread because std::pair doesn't work with
392    // std::unique_ptr in C++03.
393    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
394    unique_ptr<__thread_struct> __tsp_;
395    _Fp __fn_;
396};
397
398template <class _Fp>
399void* __thread_proxy_cxx03(void* __vp)
400{
401    std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
402    __thread_local_data().set_pointer(__p->__tsp_.release());
403    (__p->__fn_)();
404    return nullptr;
405}
406
407template <class _Fp>
408thread::thread(_Fp __f)
409{
410
411    typedef __thread_invoke_pair<_Fp> _InvokePair;
412    typedef std::unique_ptr<_InvokePair> _PairPtr;
413    _PairPtr __pp(new _InvokePair(__f));
414    int __ec = __libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
415    if (__ec == 0)
416        __pp.release();
417    else
418        __throw_system_error(__ec, "thread constructor failed");
419}
420
421#endif  // _LIBCPP_CXX03_LANG
422
423inline _LIBCPP_INLINE_VISIBILITY
424void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
425
426namespace this_thread
427{
428
429_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& __ns);
430
431template <class _Rep, class _Period>
432void
433sleep_for(const chrono::duration<_Rep, _Period>& __d)
434{
435    using namespace chrono;
436    if (__d > duration<_Rep, _Period>::zero())
437    {
438        _LIBCPP_CONSTEXPR duration<long double> _Max = nanoseconds::max();
439        nanoseconds __ns;
440        if (__d < _Max)
441        {
442            __ns = duration_cast<nanoseconds>(__d);
443            if (__ns < __d)
444                ++__ns;
445        }
446        else
447            __ns = nanoseconds::max();
448        sleep_for(__ns);
449    }
450}
451
452template <class _Clock, class _Duration>
453void
454sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
455{
456    using namespace chrono;
457    mutex __mut;
458    condition_variable __cv;
459    unique_lock<mutex> __lk(__mut);
460    while (_Clock::now() < __t)
461        __cv.wait_until(__lk, __t);
462}
463
464template <class _Duration>
465inline _LIBCPP_INLINE_VISIBILITY
466void
467sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
468{
469    using namespace chrono;
470    sleep_for(__t - steady_clock::now());
471}
472
473inline _LIBCPP_INLINE_VISIBILITY
474void yield() _NOEXCEPT {__libcpp_thread_yield();}
475
476}  // this_thread
477
478_LIBCPP_END_NAMESPACE_STD
479
480#endif // !_LIBCPP_HAS_NO_THREADS
481
482_LIBCPP_POP_MACROS
483
484#endif  // _LIBCPP_THREAD
485