Apache Portable Runtime
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apr_sdbm.h
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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;
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_FOPEN_READ and APR_FOPEN_BINARY flags are
73 * implicit)
74 * <PRE>
75 * APR_FOPEN_WRITE open for read-write access
76 * APR_FOPEN_CREATE create the sdbm if it does not exist
77 * APR_FOPEN_TRUNCATE empty the contents of the sdbm
78 * APR_FOPEN_EXCL fail for APR_FOPEN_CREATE if the file exists
79 * APR_FOPEN_DELONCLOSE delete the sdbm when closed
80 * APR_FOPEN_SHARELOCK support locking across process/machines
81 * </PRE>
82 * @param perms Permissions to apply to if created
83 * @param p The pool to use when creating the sdbm
84 * @remark The sdbm name is not a true file name, as sdbm appends suffixes
85 * for seperate data and index files.
86 */
88 apr_int32_t mode,
89 apr_fileperms_t perms, apr_pool_t *p);
90
91/**
92 * Close an sdbm file previously opened by apr_sdbm_open
93 * @param db The database to close
94 */
96
97/**
98 * Lock an sdbm database for concurency of multiple operations
99 * @param db The database to lock
100 * @param type The lock type
101 * <PRE>
102 * APR_FLOCK_SHARED
103 * APR_FLOCK_EXCLUSIVE
104 * </PRE>
105 * @remark Calls to apr_sdbm_lock may be nested. All apr_sdbm functions
106 * perform implicit locking. Since an APR_FLOCK_SHARED lock cannot be
107 * portably promoted to an APR_FLOCK_EXCLUSIVE lock, apr_sdbm_store and
108 * apr_sdbm_delete calls will fail if an APR_FLOCK_SHARED lock is held.
109 * The apr_sdbm_lock call requires the database to be opened with the
110 * APR_FOPEN_SHARELOCK mode value.
111 */
113
114/**
115 * Release an sdbm lock previously aquired by apr_sdbm_lock
116 * @param db The database to unlock
117 */
119
120/**
121 * Fetch an sdbm record value by key
122 * @param db The database
123 * @param value The value datum retrieved for this record
124 * @param key The key datum to find this record
125 */
127 apr_sdbm_datum_t *value,
128 apr_sdbm_datum_t key);
129
130/**
131 * Store an sdbm record value by key
132 * @param db The database
133 * @param key The key datum to store this record by
134 * @param value The value datum to store in this record
135 * @param opt The method used to store the record
136 * <PRE>
137 * APR_SDBM_INSERT return an error if the record exists
138 * APR_SDBM_REPLACE overwrite any existing record for key
139 * </PRE>
140 */
142 apr_sdbm_datum_t value, int opt);
143
144/**
145 * Delete an sdbm record value by key
146 * @param db The database
147 * @param key The key datum of the record to delete
148 * @remark It is not an error to delete a non-existent record.
149 */
151 const apr_sdbm_datum_t key);
152
153/**
154 * Retrieve the first record key from a dbm
155 * @param db The database
156 * @param key The key datum of the first record
157 * @remark The keys returned are not ordered. To traverse the list of keys
158 * for an sdbm opened with APR_FOPEN_SHARELOCK, the caller must use apr_sdbm_lock
159 * prior to retrieving the first record, and hold the lock until after the
160 * last call to apr_sdbm_nextkey.
161 */
163
164/**
165 * Retrieve the next record key from an sdbm
166 * @param db The database
167 * @param key The key datum of the next record
168 */
170
171/**
172 * Returns true if the sdbm database opened for read-only access
173 * @param db The database to test
174 */
176/** @} */
177#endif /* APR_SDBM_H */
APR Error Codes.
APR File I/O Handling.
apr_status_t apr_sdbm_open(apr_sdbm_t **db, const char *name, apr_int32_t mode, apr_fileperms_t perms, apr_pool_t *p)
apr_status_t apr_sdbm_lock(apr_sdbm_t *db, int type)
apr_status_t apr_sdbm_delete(apr_sdbm_t *db, const apr_sdbm_datum_t key)
apr_status_t apr_sdbm_nextkey(apr_sdbm_t *db, apr_sdbm_datum_t *key)
apr_status_t apr_sdbm_fetch(apr_sdbm_t *db, apr_sdbm_datum_t *value, apr_sdbm_datum_t key)
apr_status_t apr_sdbm_unlock(apr_sdbm_t *db)
int apr_sdbm_rdonly(apr_sdbm_t *db)
apr_status_t apr_sdbm_store(apr_sdbm_t *db, apr_sdbm_datum_t key, apr_sdbm_datum_t value, int opt)
apr_status_t apr_sdbm_firstkey(apr_sdbm_t *db, apr_sdbm_datum_t *key)
apr_status_t apr_sdbm_close(apr_sdbm_t *db)
int apr_status_t
Definition apr_errno.h:44
apr_int32_t apr_fileperms_t
Definition apr_file_info.h:125
#define APR_DECLARE(type)
Definition apr.h:523
struct apr_pool_t apr_pool_t
Definition apr_pools.h:60
Definition apr_sdbm.h:49
char * dptr
Definition apr_sdbm.h:51
int dsize
Definition apr_sdbm.h:54
Definition sdbm_private.h:49