summaryrefslogtreecommitdiffstats
path: root/rubbos/app/apache2/include/apr_sdbm.h
blob: 7fcf7f6e5391a3db5715c9c8dd752d7f11acdb6f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed 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.
 */

/*
 * sdbm - ndbm work-alike hashed database library
 * based on Per-Ake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
 * author: oz@nexus.yorku.ca
 * status: ex-public domain
 */

#ifndef APR_SDBM_H
#define APR_SDBM_H

#include "apu.h"
#include "apr_errno.h"
#include "apr_file_io.h"   /* for apr_fileperms_t */

/** 
 * @file apr_sdbm.h
 * @brief apr-util SDBM library
 */
/**
 * @defgroup APR_Util_DBM_SDBM SDBM library
 * @ingroup APR_Util_DBM
 * @{
 */

/**
 * Structure for referencing an sdbm
 */
typedef struct apr_sdbm_t apr_sdbm_t;

/**
 * Structure for referencing the datum record within an sdbm
 */
typedef struct {
    /** pointer to the data stored/retrieved */
    char *dptr;
    /** size of data */
    int dsize;
} apr_sdbm_datum_t;

/* The extensions used for the database files */
/** SDBM Directory file extension */
#define APR_SDBM_DIRFEXT	".dir"
/** SDBM page file extension */
#define APR_SDBM_PAGFEXT	".pag"

/* flags to sdbm_store */
#define APR_SDBM_INSERT     0   /**< Insert */
#define APR_SDBM_REPLACE    1   /**< Replace */
#define APR_SDBM_INSERTDUP  2   /**< Insert with duplicates */

/**
 * Open an sdbm database by file name
 * @param db The newly opened database
 * @param name The sdbm file to open
 * @param mode The flag values (APR_READ and APR_BINARY flags are implicit)
 * <PRE>
 *           APR_WRITE          open for read-write access
 *           APR_CREATE         create the sdbm if it does not exist
 *           APR_TRUNCATE       empty the contents of the sdbm
 *           APR_EXCL           fail for APR_CREATE if the file exists
 *           APR_DELONCLOSE     delete the sdbm when closed
 *           APR_SHARELOCK      support locking across process/machines
 * </PRE>
 * @param perms Permissions to apply to if created
 * @param p The pool to use when creating the sdbm
 * @remark The sdbm name is not a true file name, as sdbm appends suffixes 
 * for seperate data and index files.
 */
APU_DECLARE(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);

/**
 * Close an sdbm file previously opened by apr_sdbm_open
 * @param db The database to close
 */
APU_DECLARE(apr_status_t) apr_sdbm_close(apr_sdbm_t *db);

/**
 * Lock an sdbm database for concurency of multiple operations
 * @param db The database to lock
 * @param type The lock type
 * <PRE>
 *           APR_FLOCK_SHARED
 *           APR_FLOCK_EXCLUSIVE
 * </PRE>
 * @remark Calls to apr_sdbm_lock may be nested.  All apr_sdbm functions
 * perform implicit locking.  Since an APR_FLOCK_SHARED lock cannot be 
 * portably promoted to an APR_FLOCK_EXCLUSIVE lock, apr_sdbm_store and 
 * apr_sdbm_delete calls will fail if an APR_FLOCK_SHARED lock is held.
 * The apr_sdbm_lock call requires the database to be opened with the
 * APR_SHARELOCK mode value.
 */
APU_DECLARE(apr_status_t) apr_sdbm_lock(apr_sdbm_t *db, int type);

/**
 * Release an sdbm lock previously aquired by apr_sdbm_lock
 * @param db The database to unlock
 */
APU_DECLARE(apr_status_t) apr_sdbm_unlock(apr_sdbm_t *db);

/**
 * Fetch an sdbm record value by key
 * @param db The database 
 * @param value The value datum retrieved for this record
 * @param key The key datum to find this record
 */
APU_DECLARE(apr_status_t) apr_sdbm_fetch(apr_sdbm_t *db, 
                                         apr_sdbm_datum_t *value, 
                                         apr_sdbm_datum_t key);

/**
 * Store an sdbm record value by key
 * @param db The database 
 * @param key The key datum to store this record by
 * @param value The value datum to store in this record
 * @param opt The method used to store the record
 * <PRE>
 *           APR_SDBM_INSERT     return an error if the record exists
 *           APR_SDBM_REPLACE    overwrite any existing record for key
 * </PRE>
 */
APU_DECLARE(apr_status_t) apr_sdbm_store(apr_sdbm_t *db, apr_sdbm_datum_t key,
                                         apr_sdbm_datum_t value, int opt);

/**
 * Delete an sdbm record value by key
 * @param db The database 
 * @param key The key datum of the record to delete
 * @remark It is not an error to delete a non-existent record.
 */
APU_DECLARE(apr_status_t) apr_sdbm_delete(apr_sdbm_t *db, 
                                          const apr_sdbm_datum_t key);

/**
 * Retrieve the first record key from a dbm
 * @param db The database 
 * @param key The key datum of the first record
 * @remark The keys returned are not ordered.  To traverse the list of keys
 * for an sdbm opened with APR_SHARELOCK, the caller must use apr_sdbm_lock
 * prior to retrieving the first record, and hold the lock until after the
 * last call to apr_sdbm_nextkey.
 */
APU_DECLARE(apr_status_t) apr_sdbm_firstkey(apr_sdbm_t *db, apr_sdbm_datum_t *key);

/**
 * Retrieve the next record key from an sdbm
 * @param db The database 
 * @param key The key datum of the next record
 */
APU_DECLARE(apr_status_t) apr_sdbm_nextkey(apr_sdbm_t *db, apr_sdbm_datum_t *key);

/**
 * Returns true if the sdbm database opened for read-only access
 * @param db The database to test
 */
APU_DECLARE(int) apr_sdbm_rdonly(apr_sdbm_t *db);
/** @} */
#endif /* APR_SDBM_H */