contrib/bind-9.5.2/lib/dns/include/dns/rdatasetiter.h

   1 /*
   2  * Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or 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 1.21 2007/06/19 23:47:17 tbox Exp $ */
  19
  20 #ifndef DNS_RDATASETITER_H
  21 #define DNS_RDATASETITER_H 1
  22
  23 /*****
  24  ***** Module Info
  25  *****/
  26
  27 /*! \file dns/rdatasetiter.h
  28  * \brief
  29  * The DNS Rdataset Iterator interface allows iteration of all of the
  30  * rdatasets at a node.
  31  *
  32  * The dns_rdatasetiter_t type is like a "virtual class".  To actually use
  33  * it, an implementation of the class is required.  This implementation is
  34  * supplied by the database.
  35  *
  36  * It is the client's responsibility to call dns_rdataset_disassociate()
  37  * on all rdatasets returned.
  38  *
  39  * XXX more XXX
  40  *
  41  * MP:
  42  *\li   The iterator itself is not locked.  The caller must ensure
  43  *      synchronization.
  44  *
  45  *\li   The iterator methods ensure appropriate database locking.
  46  *
  47  * Reliability:
  48  *\li   No anticipated impact.
  49  *
  50  * Resources:
  51  *\li   TBS
  52  *
  53  * Security:
  54  *\li   No anticipated impact.
  55  *
  56  * Standards:
  57  *\li   None.
  58  */
  59
  60 /*****
  61  ***** Imports
  62  *****/
  63
  64 #include <isc/lang.h>
  65 #include <isc/magic.h>
  66 #include <isc/stdtime.h>
  67
  68 #include <dns/types.h>
  69
  70 ISC_LANG_BEGINDECLS
  71
  72 /*****
  73  ***** Types
  74  *****/
  75
  76 typedef struct dns_rdatasetitermethods {
  77         void            (*destroy)(dns_rdatasetiter_t **iteratorp);
  78         isc_result_t    (*first)(dns_rdatasetiter_t *iterator);
  79         isc_result_t    (*next)(dns_rdatasetiter_t *iterator);
  80         void            (*current)(dns_rdatasetiter_t *iterator,
  81                                    dns_rdataset_t *rdataset);
  82 } dns_rdatasetitermethods_t;
  83
  84 #define DNS_RDATASETITER_MAGIC       ISC_MAGIC('D','N','S','i')
  85 #define DNS_RDATASETITER_VALID(i)    ISC_MAGIC_VALID(i, DNS_RDATASETITER_MAGIC)
  86
  87 /*%
  88  * This structure is actually just the common prefix of a DNS db
  89  * implementation's version of a dns_rdatasetiter_t.
  90  * \brief
  91  * Direct use of this structure by clients is forbidden.  DB implementations
  92  * may change the structure.  'magic' must be #DNS_RDATASETITER_MAGIC for
  93  * any of the dns_rdatasetiter routines to work.  DB implementations must
  94  * maintain all DB rdataset iterator invariants.
  95  */
  96 struct dns_rdatasetiter {
  97         /* Unlocked. */
  98         unsigned int                    magic;
  99         dns_rdatasetitermethods_t *     methods;
 100         dns_db_t *                      db;
 101         dns_dbnode_t *                  node;
 102         dns_dbversion_t *               version;
 103         isc_stdtime_t                   now;
 104 };
 105
 106 void
 107 dns_rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp);
 108 /*%<
 109  * Destroy '*iteratorp'.
 110  *
 111  * Requires:
 112  *
 113  *\li   '*iteratorp' is a valid iterator.
 114  *
 115  * Ensures:
 116  *
 117  *\li   All resources used by the iterator are freed.
 118  *
 119  *\li   *iteratorp == NULL.
 120  */
 121
 122 isc_result_t
 123 dns_rdatasetiter_first(dns_rdatasetiter_t *iterator);
 124 /*%<
 125  * Move the rdataset cursor to the first rdataset at the node (if any).
 126  *
 127  * Requires:
 128  *\li   'iterator' is a valid iterator.
 129  *
 130  * Returns:
 131  *\li   ISC_R_SUCCESS
 132  *\li   ISC_R_NOMORE                    There are no rdatasets at the node.
 133  *
 134  *\li   Other results are possible, depending on the DB implementation.
 135  */
 136
 137 isc_result_t
 138 dns_rdatasetiter_next(dns_rdatasetiter_t *iterator);
 139 /*%<
 140  * Move the rdataset cursor to the next rdataset at the node (if any).
 141  *
 142  * Requires:
 143  *\li   'iterator' is a valid iterator.
 144  *
 145  * Returns:
 146  *\li   ISC_R_SUCCESS
 147  *\li   ISC_R_NOMORE                    There are no more rdatasets at the
 148  *                                      node.
 149  *
 150  *\li   Other results are possible, depending on the DB implementation.
 151  */
 152
 153 void
 154 dns_rdatasetiter_current(dns_rdatasetiter_t *iterator,
 155                          dns_rdataset_t *rdataset);
 156 /*%<
 157  * Return the current rdataset.
 158  *
 159  * Requires:
 160  *\li   'iterator' is a valid iterator.
 161  *
 162  *\li   'rdataset' is a valid, disassociated rdataset.
 163  *
 164  *\li   The rdataset cursor of 'iterator' is at a valid location (i.e. the
 165  *      result of last call to a cursor movement command was #ISC_R_SUCCESS).
 166  */
 167
 168 ISC_LANG_ENDDECLS
 169
 170 #endif /* DNS_RDATASETITER_H */