/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program 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, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

/*****************************************************************************
** Simulation of posix threads calls for Windows
*****************************************************************************/
#if defined (_WIN32)
/* SAFE_MUTEX will not work until the thread structure is up to date */
#undef SAFE_MUTEX
#include "mysys_priv.h"
#include <process.h>
#include <signal.h>

static void install_sigabrt_handler(void);

struct thread_start_parameter
{
  pthread_handler func;
  void *arg;
};

/**
   Adapter to @c pthread_mutex_trylock()

   @retval 0      Mutex was acquired
   @retval EBUSY  Mutex was already locked by a thread
 */
int
win_pthread_mutex_trylock(pthread_mutex_t *mutex)
{
  if (TryEnterCriticalSection(mutex))
  {
    /* Don't allow recursive lock */
    if (mutex->RecursionCount > 1){
      LeaveCriticalSection(mutex);
      return EBUSY;
    }
    return 0;
  }
  return EBUSY;
}

static unsigned int __stdcall pthread_start(void *p)
{
  struct thread_start_parameter *par= (struct thread_start_parameter *)p;
  pthread_handler func= par->func;
  void *arg= par->arg;
  free(p);
  (*func)(arg);
  return 0;
}


int pthread_create(pthread_t *thread_id, const pthread_attr_t *attr,
                   pthread_handler func, void *param)
{
  uintptr_t handle;
  struct thread_start_parameter *par;
  unsigned int  stack_size;
  int error_no;
  DBUG_ENTER("pthread_create");

  par= (struct thread_start_parameter *)malloc(sizeof(*par));
  if (!par)
   goto error_return;

  par->func= func;
  par->arg= param;
  stack_size= attr?attr->dwStackSize:0;

  handle= _beginthreadex(NULL, stack_size , pthread_start, par, 0, thread_id);
  if (!handle)
    goto error_return;
  DBUG_PRINT("info", ("thread id=%u",*thread_id));

  /* Do not need thread handle, close it */
  CloseHandle((HANDLE)handle);
  DBUG_RETURN(0);

error_return:
  error_no= errno;
  DBUG_PRINT("error",
         ("Can't create thread to handle request (error %d)",error_no));
  DBUG_RETURN(error_no);
}


void pthread_exit(void *a)
{
  _endthreadex(0);
}

int pthread_join(pthread_t thread, void **value_ptr)
{
  DWORD  ret;
  HANDLE handle;

  handle= OpenThread(SYNCHRONIZE, FALSE, thread);
  if (!handle)
  {
    errno= EINVAL;
    goto error_return;
  }

  ret= WaitForSingleObject(handle, INFINITE);

  if(ret != WAIT_OBJECT_0)
  {
    errno= EINVAL;
    goto error_return;
  }

  CloseHandle(handle);
  return 0;

error_return:
  if(handle)
    CloseHandle(handle);
  return -1;
}

int pthread_cancel(pthread_t thread)
{

  HANDLE handle= 0;
  BOOL ok= FALSE;

  handle= OpenThread(THREAD_TERMINATE, FALSE, thread);
  if (handle)
  {
     ok= TerminateThread(handle,0);
     CloseHandle(handle);
  }
  if (ok)
    return 0;

  errno= EINVAL;
  return -1;
}

/*
 One time initialization. For simplicity, we assume initializer thread
 does not exit within init_routine().
*/
int my_pthread_once(my_pthread_once_t *once_control, 
    void (*init_routine)(void))
{
  LONG state;

  /*
    Do "dirty" read to find out if initialization is already done, to
    save an interlocked operation in common case. Memory barriers are ensured by 
    Visual C++ volatile implementation.
  */
  if (*once_control == MY_PTHREAD_ONCE_DONE)
    return 0;

  state= InterlockedCompareExchange(once_control, MY_PTHREAD_ONCE_INPROGRESS,
                                        MY_PTHREAD_ONCE_INIT);

  switch(state)
  {
  case MY_PTHREAD_ONCE_INIT:
    /* This is initializer thread */
    (*init_routine)();
    *once_control= MY_PTHREAD_ONCE_DONE;
    break;

  case MY_PTHREAD_ONCE_INPROGRESS:
    /* init_routine in progress. Wait for its completion */
    while(*once_control == MY_PTHREAD_ONCE_INPROGRESS)
    {
      Sleep(1);
    }
    break;
  case MY_PTHREAD_ONCE_DONE:
    /* Nothing to do */
    break;
  }
  return 0;
}
#endif
