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Edit File: dbiterator.h
/* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #ifndef DNS_DBITERATOR_H #define DNS_DBITERATOR_H 1 /***** ***** Module Info *****/ /*! \file dns/dbiterator.h * \brief * The DNS DB Iterator interface allows iteration of all of the nodes in a * database. * * The dns_dbiterator_t type is like a "virtual class". To actually use * it, an implementation of the class is required. This implementation is * supplied by the database. * * It is the client's responsibility to call dns_db_detachnode() on all * nodes returned. * * XXX <more> XXX * * MP: *\li The iterator itself is not locked. The caller must ensure * synchronization. * *\li The iterator methods ensure appropriate database locking. * * Reliability: *\li No anticipated impact. * * Resources: *\li TBS * * Security: *\li No anticipated impact. * * Standards: *\li None. */ /***** ***** Imports *****/ #include <stdbool.h> #include <isc/lang.h> #include <isc/magic.h> #include <dns/types.h> ISC_LANG_BEGINDECLS /***** ***** Types *****/ typedef struct dns_dbiteratormethods { void (*destroy)(dns_dbiterator_t **iteratorp); isc_result_t (*first)(dns_dbiterator_t *iterator); isc_result_t (*last)(dns_dbiterator_t *iterator); isc_result_t (*seek)(dns_dbiterator_t *iterator, const dns_name_t *name); isc_result_t (*prev)(dns_dbiterator_t *iterator); isc_result_t (*next)(dns_dbiterator_t *iterator); isc_result_t (*current)(dns_dbiterator_t *iterator, dns_dbnode_t **nodep, dns_name_t *name); isc_result_t (*pause)(dns_dbiterator_t *iterator); isc_result_t (*origin)(dns_dbiterator_t *iterator, dns_name_t *name); } dns_dbiteratormethods_t; #define DNS_DBITERATOR_MAGIC ISC_MAGIC('D', 'N', 'S', 'I') #define DNS_DBITERATOR_VALID(dbi) ISC_MAGIC_VALID(dbi, DNS_DBITERATOR_MAGIC) /*% * This structure is actually just the common prefix of a DNS db * implementation's version of a dns_dbiterator_t. * * Clients may use the 'db' field of this structure. Except for that field, * direct use of this structure by clients is forbidden. DB implementations * may change the structure. 'magic' must be DNS_DBITERATOR_MAGIC for any of * the dns_dbiterator routines to work. DB iterator implementations must * maintain all DB iterator invariants. */ struct dns_dbiterator { /* Unlocked. */ unsigned int magic; dns_dbiteratormethods_t *methods; dns_db_t *db; bool relative_names; bool cleaning; }; void dns_dbiterator_destroy(dns_dbiterator_t **iteratorp); /*%< * Destroy '*iteratorp'. * * Requires: * *\li '*iteratorp' is a valid iterator. * * Ensures: * *\li All resources used by the iterator are freed. * *\li *iteratorp == NULL. */ isc_result_t dns_dbiterator_first(dns_dbiterator_t *iterator); /*%< * Move the node cursor to the first node in the database (if any). * * Requires: *\li 'iterator' is a valid iterator. * * Returns: *\li #ISC_R_SUCCESS *\li #ISC_R_NOMORE There are no nodes in the database. * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_last(dns_dbiterator_t *iterator); /*%< * Move the node cursor to the last node in the database (if any). * * Requires: *\li 'iterator' is a valid iterator. * * Returns: *\li #ISC_R_SUCCESS *\li #ISC_R_NOMORE There are no nodes in the database. * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_seek(dns_dbiterator_t *iterator, const dns_name_t *name); /*%< * Move the node cursor to the node with name 'name'. * * Requires: *\li 'iterator' is a valid iterator. * *\li 'name' is a valid name. * * Returns: *\li #ISC_R_SUCCESS *\li #ISC_R_NOTFOUND *\li #DNS_R_PARTIALMATCH * (node is at name above requested named when name has children) * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_prev(dns_dbiterator_t *iterator); /*%< * Move the node cursor to the previous node in the database (if any). * * Requires: *\li 'iterator' is a valid iterator. * * Returns: *\li #ISC_R_SUCCESS *\li #ISC_R_NOMORE There are no more nodes in the * database. * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_next(dns_dbiterator_t *iterator); /*%< * Move the node cursor to the next node in the database (if any). * * Requires: *\li 'iterator' is a valid iterator. * * Returns: *\li #ISC_R_SUCCESS *\li #ISC_R_NOMORE There are no more nodes in the * database. * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_current(dns_dbiterator_t *iterator, dns_dbnode_t **nodep, dns_name_t *name); /*%< * Return the current node. * * Notes: *\li If 'name' is not NULL, it will be set to the name of the node. * * Requires: *\li 'iterator' is a valid iterator. * *\li nodep != NULL && *nodep == NULL * *\li The node cursor of 'iterator' is at a valid location (i.e. the * result of last call to a cursor movement command was ISC_R_SUCCESS). * *\li 'name' is NULL, or is a valid name with a dedicated buffer. * * Returns: * *\li #ISC_R_SUCCESS *\li #DNS_R_NEWORIGIN If this iterator was created * with 'relative_names' set to true, then #DNS_R_NEWORIGIN will be returned *when * the origin the names are relative to changes. This result can occur only *when *'name' is not NULL. This is also a successful result. * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_pause(dns_dbiterator_t *iterator); /*%< * Pause iteration. * * Calling a cursor movement method or dns_dbiterator_current() may cause * database locks to be acquired. Rather than reacquire these locks every * time one of these routines is called, the locks may simply be held. * Calling dns_dbiterator_pause() releases any such locks. Iterator clients * should call this routine any time they are not going to execute another * iterator method in the immediate future. * * Requires: *\li 'iterator' is a valid iterator. * * Ensures: *\li Any database locks being held for efficiency of iterator access are * released. * * Returns: *\li #ISC_R_SUCCESS * *\li Other results are possible, depending on the DB implementation. */ isc_result_t dns_dbiterator_origin(dns_dbiterator_t *iterator, dns_name_t *name); /*%< * Return the origin to which returned node names are relative. * * Requires: * *\li 'iterator' is a valid relative_names iterator. * *\li 'name' is a valid name with a dedicated buffer. * * Returns: * *\li #ISC_R_SUCCESS *\li #ISC_R_NOSPACE * *\li Other results are possible, depending on the DB implementation. */ void dns_dbiterator_setcleanmode(dns_dbiterator_t *iterator, bool mode); /*%< * Indicate that the given iterator is/is not cleaning the DB. * * Notes: *\li When 'mode' is true, * * Requires: *\li 'iterator' is a valid iterator. */ ISC_LANG_ENDDECLS #endif /* DNS_DBITERATOR_H */