/* id.h : interface to FSX-internal ID functions
 *
 * ====================================================================
 *    Licensed to the Apache Software Foundation (ASF) under one
 *    or more contributor license agreements.  See the NOTICE file
 *    distributed with this work for additional information
 *    regarding copyright ownership.  The ASF licenses this file
 *    to you under the Apache License, Version 2.0 (the
 *    "License"); you may not use this file except in compliance
 *    with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing,
 *    software distributed under the License is distributed on an
 *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *    KIND, either express or implied.  See the License for the
 *    specific language governing permissions and limitations
 *    under the License.
 * ====================================================================
 */

#ifndef SVN_LIBSVN_FS_X_ID_H
#define SVN_LIBSVN_FS_X_ID_H

#include "svn_fs.h"

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/* Unique identifier for a transaction within the given repository. */
typedef apr_int64_t svn_fs_x__txn_id_t;

/* svn_fs_x__txn_id_t value for everything that is not a transaction. */
#define SVN_FS_X__INVALID_TXN_ID ((svn_fs_x__txn_id_t)(-1))

/* Change set is the umbrella term for transaction and revision in FSX.
 * Revision numbers (>=0) map 1:1 onto change sets while txns are mapped
 * onto the negatve value range. */
typedef apr_int64_t svn_fs_x__change_set_t;

/* Invalid / unused change set number. */
#define SVN_FS_X__INVALID_CHANGE_SET  ((svn_fs_x__change_set_t)(-1))

/* Return TRUE iff the CHANGE_SET refers to a revision
   (will return FALSE for SVN_INVALID_REVNUM). */
svn_boolean_t
svn_fs_x__is_revision(svn_fs_x__change_set_t change_set);

/* Return TRUE iff the CHANGE_SET refers to a transaction
   (will return FALSE for SVN_FS_X__INVALID_TXN_ID). */
svn_boolean_t
svn_fs_x__is_txn(svn_fs_x__change_set_t change_set);

/* Return the revision number that corresponds to CHANGE_SET.
   Will SVN_INVALID_REVNUM for transactions. */
svn_revnum_t
svn_fs_x__get_revnum(svn_fs_x__change_set_t change_set);

/* Return the transaction ID that corresponds to CHANGE_SET.
   Will SVN_FS_X__INVALID_TXN_ID for revisions. */
svn_fs_x__txn_id_t
svn_fs_x__get_txn_id(svn_fs_x__change_set_t change_set);

/* Convert REVNUM into a change set number */
svn_fs_x__change_set_t
svn_fs_x__change_set_by_rev(svn_revnum_t revnum);

/* Convert TXN_ID into a change set number */
svn_fs_x__change_set_t
svn_fs_x__change_set_by_txn(svn_fs_x__txn_id_t txn_id);

/* An ID in FSX consists of a creation CHANGE_SET number and some changeset-
 * local counter value (NUMBER).
 */
typedef struct svn_fs_x__id_t
{
  svn_fs_x__change_set_t change_set;

  apr_uint64_t number;
} svn_fs_x__id_t;


/*** Operations on ID parts. ***/

/* Return TRUE, if both elements of the PART is 0, i.e. this is the default
 * value if e.g. no copies were made of this node. */
svn_boolean_t
svn_fs_x__id_is_root(const svn_fs_x__id_t *part);

/* Return TRUE, if all element values of *LHS and *RHS match. */
svn_boolean_t
svn_fs_x__id_eq(const svn_fs_x__id_t *lhs,
                const svn_fs_x__id_t *rhs);

/* Parse the NUL-terminated ID part at DATA and write the result into *PART.
 */
svn_error_t *
svn_fs_x__id_parse(svn_fs_x__id_t *part,
                   const char *data);

/* Convert ID into string form, allocated in RESULT_POOL. */
svn_string_t *
svn_fs_x__id_unparse(const svn_fs_x__id_t*id,
                     apr_pool_t *result_pool);

/* Set *PART to "unused". */
void
svn_fs_x__id_reset(svn_fs_x__id_t *part);

/* Return TRUE if *PART is belongs to either a revision or transaction. */
svn_boolean_t
svn_fs_x__id_used(const svn_fs_x__id_t *part);

/* Return 0 if A and B are equal, 1 if A is "greater than" B, -1 otherwise. */
int
svn_fs_x__id_compare(const svn_fs_x__id_t *a,
                     const svn_fs_x__id_t *b);

/* Set *NODEREV_ID to the root node ID of transaction TXN_ID. */
void
svn_fs_x__init_txn_root(svn_fs_x__id_t *noderev_id,
                        svn_fs_x__txn_id_t txn_id);

/* Set *NODEREV_ID to the root node ID of revision REV. */
void
svn_fs_x__init_rev_root(svn_fs_x__id_t *noderev_id,
                        svn_revnum_t rev);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* SVN_LIBSVN_FS_X_ID_H */