1 /* rev-table.c : working with the `revisions' table 2 * 3 * ==================================================================== 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 * ==================================================================== 21 */ 22 23#include "bdb_compat.h" 24 25#include "svn_fs.h" 26#include "private/svn_skel.h" 27 28#include "../fs.h" 29#include "../err.h" 30#include "../util/fs_skels.h" 31#include "../../libsvn_fs/fs-loader.h" 32#include "bdb-err.h" 33#include "dbt.h" 34#include "rev-table.h" 35 36#include "svn_private_config.h" 37#include "private/svn_fs_util.h" 38 39 40/* Opening/creating the `revisions' table. */ 41 42int svn_fs_bdb__open_revisions_table(DB **revisions_p, 43 DB_ENV *env, 44 svn_boolean_t create) 45{ 46 const u_int32_t open_flags = (create ? (DB_CREATE | DB_EXCL) : 0); 47 DB *revisions; 48 49 BDB_ERR(svn_fs_bdb__check_version()); 50 BDB_ERR(db_create(&revisions, env, 0)); 51 BDB_ERR((revisions->open)(SVN_BDB_OPEN_PARAMS(revisions, NULL), 52 "revisions", 0, DB_RECNO, 53 open_flags, 0666)); 54 55 *revisions_p = revisions; 56 return 0; 57} 58 59 60 61/* Storing and retrieving filesystem revisions. */ 62 63 64svn_error_t * 65svn_fs_bdb__get_rev(revision_t **revision_p, 66 svn_fs_t *fs, 67 svn_revnum_t rev, 68 trail_t *trail, 69 apr_pool_t *pool) 70{ 71 base_fs_data_t *bfd = fs->fsap_data; 72 int db_err; 73 DBT key, value; 74 svn_skel_t *skel; 75 revision_t *revision; 76 77 /* Turn the revision number into a Berkeley DB record number. 78 Revisions are numbered starting with zero; Berkeley DB record 79 numbers begin with one. */ 80 db_recno_t recno = (db_recno_t) rev + 1; 81 82 if (!SVN_IS_VALID_REVNUM(rev)) 83 return svn_fs_base__err_dangling_rev(fs, rev); 84 85 svn_fs_base__trail_debug(trail, "revisions", "get"); 86 db_err = bfd->revisions->get(bfd->revisions, trail->db_txn, 87 svn_fs_base__set_dbt(&key, &recno, 88 sizeof(recno)), 89 svn_fs_base__result_dbt(&value), 90 0); 91 svn_fs_base__track_dbt(&value, pool); 92 93 /* If there's no such revision, return an appropriately specific error. */ 94 if (db_err == DB_NOTFOUND) 95 return svn_fs_base__err_dangling_rev(fs, rev); 96 97 /* Handle any other error conditions. */ 98 SVN_ERR(BDB_WRAP(fs, N_("reading filesystem revision"), db_err)); 99 100 /* Parse REVISION skel. */ 101 skel = svn_skel__parse(value.data, value.size, pool); 102 if (! skel) 103 return svn_fs_base__err_corrupt_fs_revision(fs, rev); 104 105 /* Convert skel to native type. */ 106 SVN_ERR(svn_fs_base__parse_revision_skel(&revision, skel, pool)); 107 108 *revision_p = revision; 109 return SVN_NO_ERROR; 110} 111 112 113/* Write REVISION to FS as part of TRAIL. If *REV is a valid revision 114 number, write this revision as one that corresponds to *REV, else 115 write a new revision and return its newly created revision number 116 in *REV. */ 117svn_error_t * 118svn_fs_bdb__put_rev(svn_revnum_t *rev, 119 svn_fs_t *fs, 120 const revision_t *revision, 121 trail_t *trail, 122 apr_pool_t *pool) 123{ 124 base_fs_data_t *bfd = fs->fsap_data; 125 int db_err; 126 db_recno_t recno = 0; 127 svn_skel_t *skel; 128 DBT key, value; 129 130 /* Convert native type to skel. */ 131 SVN_ERR(svn_fs_base__unparse_revision_skel(&skel, revision, pool)); 132 133 if (SVN_IS_VALID_REVNUM(*rev)) 134 { 135 DBT query, result; 136 137 /* Update the filesystem revision with the new skel. */ 138 recno = (db_recno_t) *rev + 1; 139 svn_fs_base__trail_debug(trail, "revisions", "put"); 140 db_err = bfd->revisions->put 141 (bfd->revisions, trail->db_txn, 142 svn_fs_base__set_dbt(&query, &recno, sizeof(recno)), 143 svn_fs_base__skel_to_dbt(&result, skel, pool), 0); 144 return BDB_WRAP(fs, N_("updating filesystem revision"), db_err); 145 } 146 147 svn_fs_base__trail_debug(trail, "revisions", "put"); 148 db_err = bfd->revisions->put(bfd->revisions, trail->db_txn, 149 svn_fs_base__recno_dbt(&key, &recno), 150 svn_fs_base__skel_to_dbt(&value, skel, pool), 151 DB_APPEND); 152 SVN_ERR(BDB_WRAP(fs, N_("storing filesystem revision"), db_err)); 153 154 /* Turn the record number into a Subversion revision number. 155 Revisions are numbered starting with zero; Berkeley DB record 156 numbers begin with one. */ 157 *rev = recno - 1; 158 return SVN_NO_ERROR; 159} 160 161 162 163/* Getting the youngest revision. */ 164 165 166svn_error_t * 167svn_fs_bdb__youngest_rev(svn_revnum_t *youngest_p, 168 svn_fs_t *fs, 169 trail_t *trail, 170 apr_pool_t *pool) 171{ 172 base_fs_data_t *bfd = fs->fsap_data; 173 int db_err; 174 DBC *cursor = 0; 175 DBT key, value; 176 db_recno_t recno; 177 178 SVN_ERR(svn_fs__check_fs(fs, TRUE)); 179 180 /* Create a database cursor. */ 181 svn_fs_base__trail_debug(trail, "revisions", "cursor"); 182 SVN_ERR(BDB_WRAP(fs, N_("getting youngest revision (creating cursor)"), 183 bfd->revisions->cursor(bfd->revisions, trail->db_txn, 184 &cursor, 0))); 185 186 /* Find the last entry in the `revisions' table. */ 187 db_err = svn_bdb_dbc_get(cursor, 188 svn_fs_base__recno_dbt(&key, &recno), 189 svn_fs_base__nodata_dbt(&value), 190 DB_LAST); 191 192 if (db_err) 193 { 194 /* Free the cursor. Ignore any error value --- the error above 195 is more interesting. */ 196 svn_bdb_dbc_close(cursor); 197 198 if (db_err == DB_NOTFOUND) 199 /* The revision 0 should always be present, at least. */ 200 return 201 svn_error_createf 202 (SVN_ERR_FS_CORRUPT, 0, 203 "Corrupt DB: revision 0 missing from 'revisions' table, in " 204 "filesystem '%s'", fs->path); 205 206 SVN_ERR(BDB_WRAP(fs, N_("getting youngest revision (finding last entry)"), 207 db_err)); 208 } 209 210 /* You can't commit a transaction with open cursors, because: 211 1) key/value pairs don't get deleted until the cursors referring 212 to them are closed, so closing a cursor can fail for various 213 reasons, and txn_commit shouldn't fail that way, and 214 2) using a cursor after committing its transaction can cause 215 undetectable database corruption. */ 216 SVN_ERR(BDB_WRAP(fs, N_("getting youngest revision (closing cursor)"), 217 svn_bdb_dbc_close(cursor))); 218 219 /* Turn the record number into a Subversion revision number. 220 Revisions are numbered starting with zero; Berkeley DB record 221 numbers begin with one. */ 222 *youngest_p = recno - 1; 223 return SVN_NO_ERROR; 224} 225