/* 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 as published by
   the Free Software Foundation; version 2 of the License.

   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 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 02110-1335  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>

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
