Function get_hash_link

mysys/mf_keycache.c:1513–1591

*/

static HASH_LINK *get_hash_link(KEY_CACHE *keycache,
                                int file, my_off_t filepos)
{
  reg1 HASH_LINK *hash_link, **start;
#if defined(KEYCACHE_DEBUG)
  int cnt;
#endif

  KEYCACHE_DBUG_PRINT("get_hash_link", ("fd: %u  pos: %lu",
                      (uint) file,(ulong) filepos));

restart:
  /*
     Find the bucket in the hash table for the pair (file, filepos);
     start contains the head of the bucket list,
     hash_link points to the first member of the list
  */
  hash_link= *(start= &keycache->hash_root[KEYCACHE_HASH(file, filepos)]);
#if defined(KEYCACHE_DEBUG)
  cnt= 0;
#endif
  /* Look for an element for the pair (file, filepos) in the bucket chain */
  while (hash_link &&
         (hash_link->diskpos != filepos || hash_link->file != file))
  {
    hash_link= hash_link->next;
#if defined(KEYCACHE_DEBUG)
    cnt++;
    if (! (cnt <= keycache->hash_links_used))
    {
      int i;
      for (i=0, hash_link= *start ;
           i < cnt ; i++, hash_link= hash_link->next)
      {
        KEYCACHE_DBUG_PRINT("get_hash_link", ("fd: %u  pos: %lu",
            (uint) hash_link->file,(ulong) hash_link->diskpos));
      }
    }
    KEYCACHE_DBUG_ASSERT(cnt <= keycache->hash_links_used);
#endif
  }
  if (! hash_link)
  {
    /* There is no hash link in the hash table for the pair (file, filepos) */
    if (keycache->free_hash_list)
    {
      hash_link= keycache->free_hash_list;
      keycache->free_hash_list= hash_link->next;
    }
    else if (keycache->hash_links_used < keycache->hash_links)
    {
      hash_link= &keycache->hash_link_root[keycache->hash_links_used++];
    }
    else
    {
      /* Wait for a free hash link */
      struct st_my_thread_var *thread= my_thread_var;
      KEYCACHE_PAGE page;