#include "usg_common.h"
#include "bus_error.h"

#define MAX_ERROR_LEN 256           /* Maximum length of string in per-thread
                                       buffer returned by strerror() */
#define _bus_nerr  256

int bus_errno;

static pthread_once_t once = PTHREAD_ONCE_INIT;
static pthread_key_t strerrorKey;


static char *_bus_errlist[_bus_nerr] = {
  "\0",
  "Timed out",
  "The other end is not inline",
  "Key already in use",
  "Network fault",
  "Send to self error",
  "Receive from wrong end",
  "Service stoped",
  "Exceed resource limit"

};

static void                         /* Free thread-specific data buffer */
destructor(void *buf)
{
  free(buf);
}

static void                         /* One-time key creation function */
createKey(void)
{
  int s;

  /* Allocate a unique thread-specific data key and save the address
     of the destructor for thread-specific data buffers */

  s = pthread_key_create(&strerrorKey, destructor);
  if (s != 0)
    err_exit(s, "pthread_key_create");
}

char *
bus_strerror(int err)
{
  int s;
  char *buf;
  /* Make first caller allocate key for thread-specific data */

  s = pthread_once(&once, createKey);
  if (s != 0)
    err_exit(s, "pthread_once");

  buf = (char *)pthread_getspecific(strerrorKey);
  if (buf == NULL)
  {
    /* If first call from this thread, allocate
                                   buffer for thread, and save its location */
    buf = (char *)malloc(MAX_ERROR_LEN);
    if (buf == NULL)
      err_exit(errno, "malloc");

    s = pthread_setspecific(strerrorKey, buf);
    if (s != 0)
      err_exit(s, "pthread_setspecific");
  }


  if(err < EBUS_BASE) {
    // libc错误
    if (err < 0 || err >= _sys_nerr || _sys_errlist[err] == NULL)
    {
      snprintf(buf, MAX_ERROR_LEN, "Unknown error %d", err);
    }
    else
    {
      strncpy(buf, _sys_errlist[err], MAX_ERROR_LEN - 1);
      buf[MAX_ERROR_LEN - 1] = '\0';          /* Ensure null termination */
    }
  } else {
    //自定义错误
    err -= EBUS_BASE;
    if (err < 0 || err >= _bus_nerr || _bus_errlist[err] == NULL)
    {
      snprintf(buf, MAX_ERROR_LEN, "Unknown error %d", err);
    }
    else
    {
      strncpy(buf, _bus_errlist[err], MAX_ERROR_LEN - 1);
      buf[MAX_ERROR_LEN - 1] = '\0';          /* Ensure null termination */
    }

  }

  return buf;
}