Function get_lock_data

sql/lock.cc:818–912

*/

MYSQL_LOCK *get_lock_data(THD *thd, TABLE **table_ptr, uint count, uint flags)
{
  uint i,lock_count,table_count;
  MYSQL_LOCK *sql_lock;
  THR_LOCK_DATA **locks, **locks_buf;
  TABLE **to, **table_buf;
  DBUG_ENTER("get_lock_data");

  DBUG_PRINT("info", ("count %d", count));

  for (i=lock_count=table_count=0 ; i < count ; i++)
  {
    TABLE *t= table_ptr[i];
    
    if ((likely(!t->s->tmp_table) ||
         (t->s->tmp_table == TRANSACTIONAL_TMP_TABLE)) &&
        (!(flags & GET_LOCK_SKIP_SEQUENCES) || t->s->sequence == 0))
    {
      lock_count+= t->file->lock_count();
      table_count++;
    }
  }

  /*
    Allocating twice the number of pointers for lock data for use in
    thr_multi_lock(). This function reorders the lock data, but cannot
    update the table values. So the second part of the array is copied
    from the first part immediately before calling thr_multi_lock().
  */
  size_t amount= sizeof(*sql_lock) +
                 sizeof(THR_LOCK_DATA*) * lock_count * 2 +
                 sizeof(table_ptr) * table_count;
  if (!(sql_lock= (MYSQL_LOCK*) (flags & GET_LOCK_ON_THD ?
                                 thd->alloc(amount) :
                                 my_malloc(key_memory_MYSQL_LOCK, amount,
                                           MYF(0)))))
    DBUG_RETURN(0);
  locks= locks_buf= sql_lock->locks= (THR_LOCK_DATA**) (sql_lock + 1);
  to= table_buf= sql_lock->table= (TABLE**) (locks + lock_count * 2);
  sql_lock->table_count= table_count;
  sql_lock->flags= flags;

  for (i=0 ; i < count ; i++)
  {
    TABLE *table= table_ptr[i];
    enum thr_lock_type lock_type;
    THR_LOCK_DATA **locks_start;

    if ((table->s->tmp_table && table->s->tmp_table != TRANSACTIONAL_TMP_TABLE)
       || (flags & GET_LOCK_SKIP_SEQUENCES && table->s->sequence != NULL))
      continue;
    lock_type= table->reginfo.lock_type;
    DBUG_ASSERT(lock_type != TL_WRITE_DEFAULT && lock_type != TL_READ_DEFAULT);
    locks_start= locks;
    locks= table->file->store_lock(thd, locks,
             (flags & GET_LOCK_ACTION_MASK) == GET_LOCK_UNLOCK ? TL_IGNORE :
             lock_type);
    if ((flags & GET_LOCK_ACTION_MASK) == GET_LOCK_STORE_LOCKS)