contrib/bind-9.2.4rc7/lib/dns/include/dns/rdatasetiter.h

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: rdatasetiter.h,v 1.14.2.1 2004/03/09 06:11:20 marka Exp $ */
  19
  20 #ifndef DNS_RDATASETITER_H
  21 #define DNS_RDATASETITER_H 1
  22
  23 /*****
  24  ***** Module Info
  25  *****/
  26
  27 /*
  28  * DNS Rdataset Iterator
  29  *
  30  * The DNS Rdataset Iterator interface allows iteration of all of the
  31  * rdatasets at a node.
  32  *
  33  * The dns_rdatasetiter_t type is like a "virtual class".  To actually use
  34  * it, an implementation of the class is required.  This implementation is
  35  * supplied by the database.
  36  *
  37  * It is the client's responsibility to call dns_rdataset_disassociate()
  38  * on all rdatasets returned.
  39  *
  40  * XXX <more> XXX
  41  *
  42  * MP:
  43  *      The iterator itself is not locked.  The caller must ensure
  44  *      synchronization.
  45  *
  46  *      The iterator methods ensure appropriate database locking.
  47  *
  48  * Reliability:
  49  *      No anticipated impact.
  50  *
  51  * Resources:
  52  *      <TBS>
  53  *
  54  * Security:
  55  *      No anticipated impact.
  56  *
  57  * Standards:
  58  *      None.
  59  */
  60
  61 /*****
  62  ***** Imports
  63  *****/
  64
  65 #include <isc/lang.h>
  66 #include <isc/magic.h>
  67 #include <isc/stdtime.h>
  68
  69 #include <dns/types.h>
  70
  71 ISC_LANG_BEGINDECLS
  72
  73 /*****
  74  ***** Types
  75  *****/
  76
  77 typedef struct dns_rdatasetitermethods {
  78         void            (*destroy)(dns_rdatasetiter_t **iteratorp);
  79         isc_result_t    (*first)(dns_rdatasetiter_t *iterator);
  80         isc_result_t    (*next)(dns_rdatasetiter_t *iterator);
  81         void            (*current)(dns_rdatasetiter_t *iterator,
  82                                    dns_rdataset_t *rdataset);
  83 } dns_rdatasetitermethods_t;
  84
  85 #define DNS_RDATASETITER_MAGIC       ISC_MAGIC('D','N','S','i')
  86 #define DNS_RDATASETITER_VALID(i)    ISC_MAGIC_VALID(i, DNS_RDATASETITER_MAGIC)
  87
  88 /*
  89  * This structure is actually just the common prefix of a DNS db
  90  * implementation's version of a dns_rdatasetiter_t.
  91  *
  92  * Direct use of this structure by clients is forbidden.  DB implementations
  93  * may change the structure.  'magic' must be DNS_RDATASETITER_MAGIC for
  94  * any of the dns_rdatasetiter routines to work.  DB implementations must
  95  * maintain all DB rdataset iterator invariants.
  96  */
  97 struct dns_rdatasetiter {
  98         /* Unlocked. */
  99         unsigned int                    magic;
 100         dns_rdatasetitermethods_t *     methods;
 101         dns_db_t *                      db;
 102         dns_dbnode_t *                  node;
 103         dns_dbversion_t *               version;
 104         isc_stdtime_t                   now;
 105 };
 106
 107 void
 108 dns_rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp);
 109 /*
 110  * Destroy '*iteratorp'.
 111  *
 112  * Requires:
 113  *
 114  *      '*iteratorp' is a valid iterator.
 115  *
 116  * Ensures:
 117  *
 118  *      All resources used by the iterator are freed.
 119  *
 120  *      *iteratorp == NULL.
 121  */
 122
 123 isc_result_t
 124 dns_rdatasetiter_first(dns_rdatasetiter_t *iterator);
 125 /*
 126  * Move the rdataset cursor to the first rdataset at the node (if any).
 127  *
 128  * Requires:
 129  *      'iterator' is a valid iterator.
 130  *
 131  * Returns:
 132  *      ISC_R_SUCCESS
 133  *      ISC_R_NOMORE                    There are no rdatasets at the node.
 134  *
 135  *      Other results are possible, depending on the DB implementation.
 136  */
 137
 138 isc_result_t
 139 dns_rdatasetiter_next(dns_rdatasetiter_t *iterator);
 140 /*
 141  * Move the rdataset cursor to the next rdataset at the node (if any).
 142  *
 143  * Requires:
 144  *      'iterator' is a valid iterator.
 145  *
 146  * Returns:
 147  *      ISC_R_SUCCESS
 148  *      ISC_R_NOMORE                    There are no more rdatasets at the
 149  *                                      node.
 150  *
 151  *      Other results are possible, depending on the DB implementation.
 152  */
 153
 154 void
 155 dns_rdatasetiter_current(dns_rdatasetiter_t *iterator,
 156                          dns_rdataset_t *rdataset);
 157 /*
 158  * Return the current rdataset.
 159  *
 160  * Requires:
 161  *      'iterator' is a valid iterator.
 162  *
 163  *      'rdataset' is a valid, disassociated rdataset.
 164  *
 165  *      The rdataset cursor of 'iterator' is at a valid location (i.e. the
 166  *      result of last call to a cursor movement command was ISC_R_SUCCESS).
 167  */
 168
 169 ISC_LANG_ENDDECLS
 170
 171 #endif /* DNS_RDATASETITER_H */