// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_THREADING_SUPPORT
#define _LIBCPP_THREADING_SUPPORT

#include <__config>
#include <chrono>
#include <errno.h>

#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#pragma GCC system_header
#endif

#if defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
# include <__external_threading>
#elif !defined(_LIBCPP_HAS_NO_THREADS)

#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
# include <pthread.h>
# include <sched.h>
#elif defined(_LIBCPP_HAS_THREAD_API_WIN32)
#include <windows.h>
#include <process.h>
#include <fibersapi.h>
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>


#if defined(_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL) || \
    defined(_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL)
#define _LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_FUNC_VIS
#else
#define _LIBCPP_THREAD_ABI_VISIBILITY inline _LIBCPP_INLINE_VISIBILITY
#endif

#if defined(__FreeBSD__) && defined(__clang__) && __has_attribute(no_thread_safety_analysis)
#define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis))
#else
#define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
// Mutex
typedef pthread_mutex_t __libcpp_mutex_t;
#define _LIBCPP_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER

typedef pthread_mutex_t __libcpp_recursive_mutex_t;

// Condition Variable
typedef pthread_cond_t __libcpp_condvar_t;
#define _LIBCPP_CONDVAR_INITIALIZER PTHREAD_COND_INITIALIZER

// Execute once
typedef pthread_once_t __libcpp_exec_once_flag;
#define _LIBCPP_EXEC_ONCE_INITIALIZER PTHREAD_ONCE_INIT

// Thread id
typedef pthread_t __libcpp_thread_id;

// Thread
#define _LIBCPP_NULL_THREAD 0U

typedef pthread_t __libcpp_thread_t;

// Thrad Local Storage
typedef pthread_key_t __libcpp_tls_key;

#define _LIBCPP_TLS_DESTRUCTOR_CC
#else
// Mutex
typedef SRWLOCK __libcpp_mutex_t;
#define _LIBCPP_MUTEX_INITIALIZER SRWLOCK_INIT

typedef CRITICAL_SECTION __libcpp_recursive_mutex_t;

// Condition Variable
typedef CONDITION_VARIABLE __libcpp_condvar_t;
#define _LIBCPP_CONDVAR_INITIALIZER CONDITION_VARIABLE_INIT

// Execute Once
typedef INIT_ONCE __libcpp_exec_once_flag;
#define _LIBCPP_EXEC_ONCE_INITIALIZER INIT_ONCE_STATIC_INIT

// Thread ID
typedef DWORD __libcpp_thread_id;

// Thread
#define _LIBCPP_NULL_THREAD 0U

typedef HANDLE __libcpp_thread_t;

// Thread Local Storage
typedef DWORD __libcpp_tls_key;

#define _LIBCPP_TLS_DESTRUCTOR_CC WINAPI
#endif

// Mutex
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_mutex_lock(__libcpp_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_mutex_unlock(__libcpp_mutex_t *__m);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_mutex_destroy(__libcpp_mutex_t *__m);

// Condition variable
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_condvar_signal(__libcpp_condvar_t* __cv);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_condvar_broadcast(__libcpp_condvar_t* __cv);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_condvar_wait(__libcpp_condvar_t* __cv, __libcpp_mutex_t* __m);

_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
                               timespec *__ts);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_condvar_destroy(__libcpp_condvar_t* __cv);

// Execute once
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_execute_once(__libcpp_exec_once_flag *flag,
                          void (*init_routine)(void));

// Thread id
_LIBCPP_THREAD_ABI_VISIBILITY
bool __libcpp_thread_id_equal(__libcpp_thread_id t1, __libcpp_thread_id t2);

_LIBCPP_THREAD_ABI_VISIBILITY
bool __libcpp_thread_id_less(__libcpp_thread_id t1, __libcpp_thread_id t2);

// Thread
_LIBCPP_THREAD_ABI_VISIBILITY
bool __libcpp_thread_isnull(const __libcpp_thread_t *__t);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
                           void *__arg);

_LIBCPP_THREAD_ABI_VISIBILITY
__libcpp_thread_id __libcpp_thread_get_current_id();

_LIBCPP_THREAD_ABI_VISIBILITY
__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_thread_join(__libcpp_thread_t *__t);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_thread_detach(__libcpp_thread_t *__t);

_LIBCPP_THREAD_ABI_VISIBILITY
void __libcpp_thread_yield();

_LIBCPP_THREAD_ABI_VISIBILITY
void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns);

// Thread local storage
_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_tls_create(__libcpp_tls_key* __key,
                        void(_LIBCPP_TLS_DESTRUCTOR_CC* __at_exit)(void*));

_LIBCPP_THREAD_ABI_VISIBILITY
void *__libcpp_tls_get(__libcpp_tls_key __key);

_LIBCPP_THREAD_ABI_VISIBILITY
int __libcpp_tls_set(__libcpp_tls_key __key, void *__p);

#if !defined(_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL) || \
    defined(_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL)

#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)

int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m)
{
  pthread_mutexattr_t attr;
  int __ec = pthread_mutexattr_init(&attr);
  if (__ec)
    return __ec;
  __ec = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
  if (__ec) {
    pthread_mutexattr_destroy(&attr);
    return __ec;
  }
  __ec = pthread_mutex_init(__m, &attr);
  if (__ec) {
    pthread_mutexattr_destroy(&attr);
    return __ec;
  }
  __ec = pthread_mutexattr_destroy(&attr);
  if (__ec) {
    pthread_mutex_destroy(__m);
    return __ec;
  }
  return 0;
}

int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m)
{
  return pthread_mutex_lock(__m);
}

bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m)
{
  return pthread_mutex_trylock(__m) == 0;
}

int __libcpp_recursive_mutex_unlock(__libcpp_mutex_t *__m)
{
  return pthread_mutex_unlock(__m);
}

int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m)
{
  return pthread_mutex_destroy(__m);
}

int __libcpp_mutex_lock(__libcpp_mutex_t *__m)
{
  return pthread_mutex_lock(__m);
}

bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m)
{
  return pthread_mutex_trylock(__m) == 0;
}

int __libcpp_mutex_unlock(__libcpp_mutex_t *__m)
{
  return pthread_mutex_unlock(__m);
}

int __libcpp_mutex_destroy(__libcpp_mutex_t *__m)
{
  return pthread_mutex_destroy(__m);
}

// Condition Variable
int __libcpp_condvar_signal(__libcpp_condvar_t *__cv)
{
  return pthread_cond_signal(__cv);
}

int __libcpp_condvar_broadcast(__libcpp_condvar_t *__cv)
{
  return pthread_cond_broadcast(__cv);
}

int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
{
  return pthread_cond_wait(__cv, __m);
}

int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
                               timespec *__ts)
{
  return pthread_cond_timedwait(__cv, __m, __ts);
}

int __libcpp_condvar_destroy(__libcpp_condvar_t *__cv)
{
  return pthread_cond_destroy(__cv);
}

// Execute once
int __libcpp_execute_once(__libcpp_exec_once_flag *flag,
                          void (*init_routine)(void)) {
  return pthread_once(flag, init_routine);
}

// Thread id
// Returns non-zero if the thread ids are equal, otherwise 0
bool __libcpp_thread_id_equal(__libcpp_thread_id t1, __libcpp_thread_id t2)
{
  return pthread_equal(t1, t2) != 0;
}

// Returns non-zero if t1 < t2, otherwise 0
bool __libcpp_thread_id_less(__libcpp_thread_id t1, __libcpp_thread_id t2)
{
  return t1 < t2;
}

// Thread
bool __libcpp_thread_isnull(const __libcpp_thread_t *__t) {
  return *__t == 0;
}

int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
                           void *__arg)
{
  return pthread_create(__t, 0, __func, __arg);
}

__libcpp_thread_id __libcpp_thread_get_current_id()
{
  return pthread_self();
}

__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t)
{
  return *__t;
}

int __libcpp_thread_join(__libcpp_thread_t *__t)
{
  return pthread_join(*__t, 0);
}

int __libcpp_thread_detach(__libcpp_thread_t *__t)
{
  return pthread_detach(*__t);
}

void __libcpp_thread_yield()
{
  sched_yield();
}

void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
{
   using namespace chrono;
   seconds __s = duration_cast<seconds>(__ns);
   timespec __ts;
   typedef decltype(__ts.tv_sec) ts_sec;
   _LIBCPP_CONSTEXPR ts_sec __ts_sec_max = numeric_limits<ts_sec>::max();

   if (__s.count() < __ts_sec_max)
   {
     __ts.tv_sec = static_cast<ts_sec>(__s.count());
     __ts.tv_nsec = static_cast<decltype(__ts.tv_nsec)>((__ns - __s).count());
   }
   else
   {
     __ts.tv_sec = __ts_sec_max;
     __ts.tv_nsec = 999999999; // (10^9 - 1)
   }

   while (nanosleep(&__ts, &__ts) == -1 && errno == EINTR);
}

// Thread local storage
int __libcpp_tls_create(__libcpp_tls_key *__key, void (*__at_exit)(void *))
{
  return pthread_key_create(__key, __at_exit);
}

void *__libcpp_tls_get(__libcpp_tls_key __key)
{
  return pthread_getspecific(__key);
}

int __libcpp_tls_set(__libcpp_tls_key __key, void *__p)
{
    return pthread_setspecific(__key, __p);
}

#elif defined(_LIBCPP_HAS_THREAD_API_WIN32)

// Mutex
int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m)
{
  InitializeCriticalSection(__m);
  return 0;
}

int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m)
{
  EnterCriticalSection(__m);
  return 0;
}

bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m)
{
  return TryEnterCriticalSection(__m) != 0;
}

int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m)
{
  LeaveCriticalSection(__m);
  return 0;
}

int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m)
{
  DeleteCriticalSection(__m);
  return 0;
}

int __libcpp_mutex_lock(__libcpp_mutex_t *__m)
{
  AcquireSRWLockExclusive(__m);
  return 0;
}

bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m)
{
  return TryAcquireSRWLockExclusive(__m) != 0;
}

int __libcpp_mutex_unlock(__libcpp_mutex_t *__m)
{
  ReleaseSRWLockExclusive(__m);
  return 0;
}

int __libcpp_mutex_destroy(__libcpp_mutex_t *__m)
{
  static_cast<void>(__m);
  return 0;
}

// Condition Variable
int __libcpp_condvar_signal(__libcpp_condvar_t *__cv)
{
  WakeConditionVariable(__cv);
  return 0;
}

int __libcpp_condvar_broadcast(__libcpp_condvar_t *__cv)
{
  WakeAllConditionVariable(__cv);
  return 0;
}

int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
{
  SleepConditionVariableSRW(__cv, __m, INFINITE, 0);
  return 0;
}

int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
                               timespec *__ts)
{
  using namespace _VSTD::chrono;

  auto duration = seconds(__ts->tv_sec) + nanoseconds(__ts->tv_nsec);
  auto abstime =
      system_clock::time_point(duration_cast<system_clock::duration>(duration));
  auto timeout_ms = duration_cast<milliseconds>(abstime - system_clock::now());

  if (!SleepConditionVariableSRW(__cv, __m,
                                 timeout_ms.count() > 0 ? timeout_ms.count()
                                                        : 0,
                                 0))
    {
      auto __ec = GetLastError();
      return __ec == ERROR_TIMEOUT ? ETIMEDOUT : __ec;
    }
  return 0;
}

int __libcpp_condvar_destroy(__libcpp_condvar_t *__cv)
{
  static_cast<void>(__cv);
  return 0;
}

// Execute Once
static inline _LIBCPP_ALWAYS_INLINE BOOL CALLBACK
__libcpp_init_once_execute_once_thunk(PINIT_ONCE __init_once, PVOID __parameter,
                                      PVOID *__context)
{
  static_cast<void>(__init_once);
  static_cast<void>(__context);

  void (*init_routine)(void) = reinterpret_cast<void (*)(void)>(__parameter);
  init_routine();
  return TRUE;
}

int __libcpp_execute_once(__libcpp_exec_once_flag *__flag,
                          void (*__init_routine)(void))
{
  if (!InitOnceExecuteOnce(__flag, __libcpp_init_once_execute_once_thunk,
                           reinterpret_cast<void *>(__init_routine), NULL))
    return GetLastError();
  return 0;
}

// Thread ID
bool __libcpp_thread_id_equal(__libcpp_thread_id __lhs,
                              __libcpp_thread_id __rhs)
{
  return __lhs == __rhs;
}

bool __libcpp_thread_id_less(__libcpp_thread_id __lhs, __libcpp_thread_id __rhs)
{
  return __lhs < __rhs;
}

// Thread
struct __libcpp_beginthreadex_thunk_data
{
  void *(*__func)(void *);
  void *__arg;
};

static inline _LIBCPP_ALWAYS_INLINE unsigned WINAPI
__libcpp_beginthreadex_thunk(void *__raw_data)
{
  auto *__data =
      static_cast<__libcpp_beginthreadex_thunk_data *>(__raw_data);
  auto *__func = __data->__func;
  void *__arg = __data->__arg;
  delete __data;
  return static_cast<unsigned>(reinterpret_cast<uintptr_t>(__func(__arg)));
}

bool __libcpp_thread_isnull(const __libcpp_thread_t *__t) {
  return *__t == 0;
}

int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
                           void *__arg)
{
  auto *__data = new __libcpp_beginthreadex_thunk_data;
  __data->__func = __func;
  __data->__arg = __arg;

  *__t = reinterpret_cast<HANDLE>(_beginthreadex(nullptr, 0,
                                                 __libcpp_beginthreadex_thunk,
                                                 __data, 0, nullptr));

  if (*__t)
    return 0;
  return GetLastError();
}

__libcpp_thread_id __libcpp_thread_get_current_id()
{
  return GetCurrentThreadId();
}

__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t)
{
  return GetThreadId(*__t);
}

int __libcpp_thread_join(__libcpp_thread_t *__t)
{
  if (WaitForSingleObjectEx(*__t, INFINITE, FALSE) == WAIT_FAILED)
    return GetLastError();
  if (!CloseHandle(*__t))
    return GetLastError();
  return 0;
}

int __libcpp_thread_detach(__libcpp_thread_t *__t)
{
  if (!CloseHandle(*__t))
    return GetLastError();
  return 0;
}

void __libcpp_thread_yield()
{
  SwitchToThread();
}

void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
{
  using namespace chrono;
  // round-up to the nearest milisecond
  milliseconds __ms =
      duration_cast<milliseconds>(__ns + chrono::nanoseconds(999999));
  // FIXME(compnerd) this should be an alertable sleep (WFSO or SleepEx)
  Sleep(__ms.count());
}

// Thread Local Storage
int __libcpp_tls_create(__libcpp_tls_key* __key,
                        void(_LIBCPP_TLS_DESTRUCTOR_CC* __at_exit)(void*))
{
  *__key = FlsAlloc(__at_exit);
  if (*__key == FLS_OUT_OF_INDEXES)
    return GetLastError();
  return 0;
}

void *__libcpp_tls_get(__libcpp_tls_key __key)
{
  return FlsGetValue(__key);
}

int __libcpp_tls_set(__libcpp_tls_key __key, void *__p)
{
  if (!FlsSetValue(__key, __p))
    return GetLastError();
  return 0;
}

#endif // _LIBCPP_HAS_THREAD_API_PTHREAD

#endif // !_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL || _LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // !_LIBCPP_HAS_NO_THREADS

#endif // _LIBCPP_THREADING_SUPPORT
