/*****************************************************************************

Copyright (c) 1995, 2018, 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, version 2.0, as published by the
Free Software Foundation.

This program is also distributed with certain software (including but not
limited to OpenSSL) that is licensed under separate terms, as designated in a
particular file or component or in included license documentation. The authors
of MySQL hereby grant you an additional permission to link the program and
your derivative works with the separately licensed software that they have
included with MySQL.

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, version 2.0,
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 02110-1301  USA

*****************************************************************************/

/** @file include/sync0arr.ic
 The wait array for synchronization primitives

 Inline code

 Created 9/5/1995 Heikki Tuuri
 *******************************************************/

extern ulint sync_array_size;
extern sync_array_t **sync_wait_array;

#include "ut0counter.h"

/** Get an instance of the sync wait array.
 @return an instance of the sync wait array. */

UNIV_INLINE
sync_array_t *sync_array_get() {
  if (sync_array_size <= 1) {
    return (sync_wait_array[0]);
  }

  return (
      sync_wait_array[default_indexer_t<>::get_rnd_index() % sync_array_size]);
}

/** Get an instance of the sync wait array and reserve a wait array cell
 in the instance for waiting for an object. The event of the cell is
 reset to nonsignalled state.
 If reserving cell of the instance fails, try to get another new
 instance until we can reserve an empty cell of it.
 @return the sync array reserved, never NULL. */
UNIV_INLINE
sync_array_t *sync_array_get_and_reserve_cell(
    void *object,       /*!< in: pointer to the object to wait for */
    ulint type,         /*!< in: lock request type */
    const char *file,   /*!< in: file where requested */
    ulint line,         /*!< in: line where requested */
    sync_cell_t **cell) /*!< out: the cell reserved, never NULL */
{
  sync_array_t *sync_arr = NULL;

  *cell = NULL;
  for (ulint i = 0; i < sync_array_size && *cell == NULL; ++i) {
    /* Although the sync_array is get in a random way currently,
    we still try at most sync_array_size times, in case any
    of the sync_array we get is full */
    sync_arr = sync_array_get();
    *cell = sync_array_reserve_cell(sync_arr, object, type, file, line);
  }

  /* This won't be true every time, for the loop above may execute
  more than srv_sync_array_size times to reserve a cell.
  But an assertion here makes the code more solid. */
  ut_a(*cell != NULL);

  return (sync_arr);
}