Function link_into_queue

mysys/mf_keycache.c:789–809

*/

static void link_into_queue(KEYCACHE_WQUEUE *wqueue,
                                   struct st_my_thread_var *thread)
{
  struct st_my_thread_var *last;

  DBUG_ASSERT(!thread->next && !thread->prev);
  if (! (last= wqueue->last_thread))
  {
    /* Queue is empty */
    thread->next= thread;
    thread->prev= &thread->next;
  }
  else
  {
    thread->prev= last->next->prev;
    last->next->prev= &thread->next;
    thread->next= last->next;
    last->next= thread;
  }
  wqueue->last_thread= thread;
}

/*
  Unlink a thread from double-linked queue of waiting threads