text: /*	$NetBSD: journal.h,v 1.5 2014/12/10 04:37:58 christos Exp $	*/
  
  /*
   * Copyright (C) 2004-2009, 2011, 2013  Internet Systems Consortium, Inc. ("ISC")
   * Copyright (C) 1999-2001  Internet Software Consortium.
   *
   * Permission to use, copy, modify, and/or distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
   * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
   * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
   * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
   * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
   * PERFORMANCE OF THIS SOFTWARE.
   */
  
  /* Id: journal.h,v 1.43 2011/12/22 07:32:41 each Exp  */
  
  #ifndef DNS_JOURNAL_H
  #define DNS_JOURNAL_H 1
  
  /*****
   ***** Module Info
   *****/
  
  /*! \file dns/journal.h
   * \brief
   * Database journaling.
   */
  
  /***
   *** Imports
   ***/
  
  #include <isc/lang.h>
  #include <isc/magic.h>
  
  #include <dns/name.h>
  #include <dns/diff.h>
  #include <dns/rdata.h>
  #include <dns/types.h>
  
  /***
   *** Defines.
   ***/
  #define DNS_JOURNALOPT_RESIGN	0x00000001
  
  #define DNS_JOURNAL_READ	0x00000000	/* ISC_FALSE */
  #define DNS_JOURNAL_CREATE	0x00000001	/* ISC_TRUE */
  #define DNS_JOURNAL_WRITE	0x00000002
  
  /***
   *** Types
   ***/
  
  /*%
   * A dns_journal_t represents an open journal file.  This is an opaque type.
   *
   * A particular dns_journal_t object may be opened for writing, in which case
   * it can be used for writing transactions to a journal file, or it can be
   * opened for reading, in which case it can be used for reading transactions
   * from (iterating over) a journal file.  A single dns_journal_t object may
   * not be used for both purposes.
   */
  typedef struct dns_journal dns_journal_t;
  
  
  /***
   *** Functions
   ***/
  
  ISC_LANG_BEGINDECLS
  
  /**************************************************************************/
  
  isc_result_t
  dns_db_createsoatuple(dns_db_t *db, dns_dbversion_t *ver, isc_mem_t *mctx,
  		      dns_diffop_t op, dns_difftuple_t **tp);
  /*!< brief
   * Create a diff tuple for the current database SOA.
   * XXX this probably belongs somewhere else.
   */
  
  
  /*@{*/
  #define DNS_SERIAL_GT(a, b) ((int)(((a) - (b)) & 0xFFFFFFFF) > 0)
  #define DNS_SERIAL_GE(a, b) ((int)(((a) - (b)) & 0xFFFFFFFF) >= 0)
  /*!< brief
   * Compare SOA serial numbers.  DNS_SERIAL_GT(a, b) returns true iff
   * a is "greater than" b where "greater than" is as defined in RFC1982.
   * DNS_SERIAL_GE(a, b) returns true iff a is "greater than or equal to" b.
   */
  /*@}*/
  
  /**************************************************************************/
  /*
   * Journal object creation and destruction.
   */
  
  isc_result_t
  dns_journal_open(isc_mem_t *mctx, const char *filename, unsigned int mode,
  		 dns_journal_t **journalp);
  /*%<
   * Open the journal file 'filename' and create a dns_journal_t object for it.
   *
   * DNS_JOURNAL_CREATE open the journal for reading and writing and create
   * the journal if it does not exist.
   * DNS_JOURNAL_WRITE open the journal for reading and writing.
   * DNS_JOURNAL_READ open the journal for reading only.
   */
  
  void
  dns_journal_destroy(dns_journal_t **journalp);
  /*%<
   * Destroy a dns_journal_t, closing any open files and freeing its memory.
   */
  
  /**************************************************************************/
  /*
   * Writing transactions to journals.
   */
  
  isc_result_t
  dns_journal_begin_transaction(dns_journal_t *j);
  /*%<
   * Prepare to write a new transaction to the open journal file 'j'.
   *
   * Requires:
   *     \li 'j' is open for writing.
   */
  
  isc_result_t
  dns_journal_writediff(dns_journal_t *j, dns_diff_t *diff);
  /*%<
   * Write 'diff' to the current transaction of journal file 'j'.
   *
   * Requires:
   * \li     'j' is open for writing and dns_journal_begin_transaction()
   * 	has been called.
   *
   *\li 	'diff' is a full or partial, correctly ordered IXFR
   *      difference sequence.
   */
  
  isc_result_t
  dns_journal_commit(dns_journal_t *j);
  /*%<
   * Commit the current transaction of journal file 'j'.
   *
   * Requires:
   * \li     'j' is open for writing and dns_journal_begin_transaction()
   * 	has been called.
   *
   *   \li   dns_journal_writediff() has been called one or more times
   * 	to form a complete, correctly ordered IXFR difference
   *      sequence.
   */
  
  isc_result_t
  dns_journal_write_transaction(dns_journal_t *j, dns_diff_t *diff);
  /*%
   * Write a complete transaction at once to a journal file,
   * sorting it if necessary, and commit it.  Equivalent to calling
   * dns_diff_sort(), dns_journal_begin_transaction(),
   * dns_journal_writediff(), and dns_journal_commit().
   *
   * Requires:
   *\li      'j' is open for writing.
   *
   * \li	'diff' contains exactly one SOA deletion, one SOA addition
   *       with a greater serial number, and possibly other changes,
   *       in arbitrary order.
   */
  
  /**************************************************************************/
  /*
   * Reading transactions from journals.
   */
  
  isc_uint32_t
  dns_journal_first_serial(dns_journal_t *j);
  isc_uint32_t
  dns_journal_last_serial(dns_journal_t *j);
  /*%<
   * Get the first and last addressable serial number in the journal.
   */
  
  isc_result_t
  dns_journal_iter_init(dns_journal_t *j,
  		      isc_uint32_t begin_serial, isc_uint32_t end_serial);
  /*%<
   * Prepare to iterate over the transactions that will bring the database
   * from SOA serial number 'begin_serial' to 'end_serial'.
   *
   * Returns:
   *\li	ISC_R_SUCCESS
   *\li	ISC_R_RANGE	begin_serial is outside the addressable range.
   *\li	ISC_R_NOTFOUND	begin_serial is within the range of addressable
   *			serial numbers covered by the journal, but
   *			this particular serial number does not exist.
   */
  
  /*@{*/
  isc_result_t
  dns_journal_first_rr(dns_journal_t *j);
  isc_result_t
  dns_journal_next_rr(dns_journal_t *j);
  /*%<
   * Position the iterator at the first/next RR in a journal
   * transaction sequence established using dns_journal_iter_init().
   *
   * Requires:
   *    \li  dns_journal_iter_init() has been called.
   *
   */
  /*@}*/
  
  void
  dns_journal_current_rr(dns_journal_t *j, dns_name_t **name, isc_uint32_t *ttl,
  		       dns_rdata_t **rdata);
  /*%<
   * Get the name, ttl, and rdata of the current journal RR.
   *
   * Requires:
   * \li     The last call to dns_journal_first_rr() or dns_journal_next_rr()
   *      returned ISC_R_SUCCESS.
   */
  
  /**************************************************************************/
  /*
   * Database roll-forward.
   */
  
  isc_result_t
  dns_journal_rollforward(isc_mem_t *mctx, dns_db_t *db, unsigned int options,
  			const char *filename);
  /*%<
   * Roll forward (play back) the journal file "filename" into the
   * database "db".  This should be called when the server starts
   * after a shutdown or crash.
   *
   * Requires:
   *\li   'mctx' is a valid memory context.
   *\li	'db' is a valid database which does not have a version
   *           open for writing.
   *\li   'filename' is the name of the journal file belonging to 'db'.
   *
   * Returns:
   *\li	DNS_R_NOJOURNAL when journal does not exist.
   *\li	ISC_R_NOTFOUND when current serial in not in journal.
   *\li	ISC_R_RANGE when current serial in not in journals range.
   *\li	ISC_R_SUCCESS journal has been applied successfully to database.
   *	others
   */
  
  isc_result_t
  dns_journal_print(isc_mem_t *mctx, const char *filename, FILE *file);
  /* For debugging not general use */
  
  isc_result_t
  dns_db_diff(isc_mem_t *mctx,
  	    dns_db_t *dba, dns_dbversion_t *dbvera,
  	    dns_db_t *dbb, dns_dbversion_t *dbverb,
  	    const char *journal_filename);
  
  isc_result_t
  dns_db_diffx(dns_diff_t *diff, dns_db_t *dba, dns_dbversion_t *dbvera,
  	     dns_db_t *dbb, dns_dbversion_t *dbverb,
  	     const char *journal_filename);
  /*%<
   * Compare the databases 'dba' and 'dbb' and generate a diff/journal
   * entry containing the changes to make 'dba' from 'dbb' (note
   * the order).  This journal entry will consist of a single,
   * possibly very large transaction.  Append the journal
   * entry to the journal file specified by 'journal_filename' if
   * non-NULL.
   */
  
  isc_result_t
  dns_journal_compact(isc_mem_t *mctx, char *filename, isc_uint32_t serial,
  		    isc_uint32_t target_size);
  /*%<
   * Attempt to compact the journal if it is greater that 'target_size'.
   * Changes from 'serial' onwards will be preserved.  If the journal
   * exists and is non-empty 'serial' must exist in the journal.
   */
  
  isc_boolean_t
  dns_journal_get_sourceserial(dns_journal_t *j, isc_uint32_t *sourceserial);
  void
  dns_journal_set_sourceserial(dns_journal_t *j, isc_uint32_t sourceserial);
  /*%<
   * Get and set source serial.
   *
   * Returns:
   *	 ISC_TRUE if sourceserial has previously been set.
   */
  
  ISC_LANG_ENDDECLS
  
  #endif /* DNS_JOURNAL_H */
  