1/* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* 18 * sdbm - ndbm work-alike hashed database library 19 * based on Per-Ake Larson's Dynamic Hashing algorithms. BIT 18 (1978). 20 * author: oz@nexus.yorku.ca 21 * status: ex-public domain 22 */ 23 24#ifndef APR_SDBM_H 25#define APR_SDBM_H 26 27#include "apu.h" 28#include "apr_errno.h" 29#include "apr_file_io.h" /* for apr_fileperms_t */ 30 31/** 32 * @file apr_sdbm.h 33 * @brief apr-util SDBM library 34 */ 35/** 36 * @defgroup APR_Util_DBM_SDBM SDBM library 37 * @ingroup APR_Util_DBM 38 * @{ 39 */ 40 41/** 42 * Structure for referencing an sdbm 43 */ 44typedef struct apr_sdbm_t apr_sdbm_t; 45 46/** 47 * Structure for referencing the datum record within an sdbm 48 */ 49typedef struct { 50 /** pointer to the data stored/retrieved */ 51 char *dptr; 52 /** size of data */ 53 /* apr_ssize_t for release 2.0??? */ 54 int dsize; 55} apr_sdbm_datum_t; 56 57/* The extensions used for the database files */ 58/** SDBM Directory file extension */ 59#define APR_SDBM_DIRFEXT ".dir" 60/** SDBM page file extension */ 61#define APR_SDBM_PAGFEXT ".pag" 62 63/* flags to sdbm_store */ 64#define APR_SDBM_INSERT 0 /**< Insert */ 65#define APR_SDBM_REPLACE 1 /**< Replace */ 66#define APR_SDBM_INSERTDUP 2 /**< Insert with duplicates */ 67 68/** 69 * Open an sdbm database by file name 70 * @param db The newly opened database 71 * @param name The sdbm file to open 72 * @param mode The flag values (APR_READ and APR_BINARY flags are implicit) 73 * <PRE> 74 * APR_WRITE open for read-write access 75 * APR_CREATE create the sdbm if it does not exist 76 * APR_TRUNCATE empty the contents of the sdbm 77 * APR_EXCL fail for APR_CREATE if the file exists 78 * APR_DELONCLOSE delete the sdbm when closed 79 * APR_SHARELOCK support locking across process/machines 80 * </PRE> 81 * @param perms Permissions to apply to if created 82 * @param p The pool to use when creating the sdbm 83 * @remark The sdbm name is not a true file name, as sdbm appends suffixes 84 * for seperate data and index files. 85 */ 86APU_DECLARE(apr_status_t) apr_sdbm_open(apr_sdbm_t **db, const char *name, 87 apr_int32_t mode, 88 apr_fileperms_t perms, apr_pool_t *p); 89 90/** 91 * Close an sdbm file previously opened by apr_sdbm_open 92 * @param db The database to close 93 */ 94APU_DECLARE(apr_status_t) apr_sdbm_close(apr_sdbm_t *db); 95 96/** 97 * Lock an sdbm database for concurency of multiple operations 98 * @param db The database to lock 99 * @param type The lock type 100 * <PRE> 101 * APR_FLOCK_SHARED 102 * APR_FLOCK_EXCLUSIVE 103 * </PRE> 104 * @remark Calls to apr_sdbm_lock may be nested. All apr_sdbm functions 105 * perform implicit locking. Since an APR_FLOCK_SHARED lock cannot be 106 * portably promoted to an APR_FLOCK_EXCLUSIVE lock, apr_sdbm_store and 107 * apr_sdbm_delete calls will fail if an APR_FLOCK_SHARED lock is held. 108 * The apr_sdbm_lock call requires the database to be opened with the 109 * APR_SHARELOCK mode value. 110 */ 111APU_DECLARE(apr_status_t) apr_sdbm_lock(apr_sdbm_t *db, int type); 112 113/** 114 * Release an sdbm lock previously aquired by apr_sdbm_lock 115 * @param db The database to unlock 116 */ 117APU_DECLARE(apr_status_t) apr_sdbm_unlock(apr_sdbm_t *db); 118 119/** 120 * Fetch an sdbm record value by key 121 * @param db The database 122 * @param value The value datum retrieved for this record 123 * @param key The key datum to find this record 124 */ 125APU_DECLARE(apr_status_t) apr_sdbm_fetch(apr_sdbm_t *db, 126 apr_sdbm_datum_t *value, 127 apr_sdbm_datum_t key); 128 129/** 130 * Store an sdbm record value by key 131 * @param db The database 132 * @param key The key datum to store this record by 133 * @param value The value datum to store in this record 134 * @param opt The method used to store the record 135 * <PRE> 136 * APR_SDBM_INSERT return an error if the record exists 137 * APR_SDBM_REPLACE overwrite any existing record for key 138 * </PRE> 139 */ 140APU_DECLARE(apr_status_t) apr_sdbm_store(apr_sdbm_t *db, apr_sdbm_datum_t key, 141 apr_sdbm_datum_t value, int opt); 142 143/** 144 * Delete an sdbm record value by key 145 * @param db The database 146 * @param key The key datum of the record to delete 147 * @remark It is not an error to delete a non-existent record. 148 */ 149APU_DECLARE(apr_status_t) apr_sdbm_delete(apr_sdbm_t *db, 150 const apr_sdbm_datum_t key); 151 152/** 153 * Retrieve the first record key from a dbm 154 * @param db The database 155 * @param key The key datum of the first record 156 * @remark The keys returned are not ordered. To traverse the list of keys 157 * for an sdbm opened with APR_SHARELOCK, the caller must use apr_sdbm_lock 158 * prior to retrieving the first record, and hold the lock until after the 159 * last call to apr_sdbm_nextkey. 160 */ 161APU_DECLARE(apr_status_t) apr_sdbm_firstkey(apr_sdbm_t *db, apr_sdbm_datum_t *key); 162 163/** 164 * Retrieve the next record key from an sdbm 165 * @param db The database 166 * @param key The key datum of the next record 167 */ 168APU_DECLARE(apr_status_t) apr_sdbm_nextkey(apr_sdbm_t *db, apr_sdbm_datum_t *key); 169 170/** 171 * Returns true if the sdbm database opened for read-only access 172 * @param db The database to test 173 */ 174APU_DECLARE(int) apr_sdbm_rdonly(apr_sdbm_t *db); 175/** @} */ 176#endif /* APR_SDBM_H */ 177