database.h 52.5 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
// Copyright (C) 2011  Internet Systems Consortium, Inc. ("ISC")
//
// 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.

#ifndef __DATABASE_DATASRC_H
#define __DATABASE_DATASRC_H

18 19
#include <string>

20
#include <boost/scoped_ptr.hpp>
21
#include <boost/tuple/tuple.hpp>
22

23 24
#include <dns/rrclass.h>
#include <dns/rrset.h>
25
#include <dns/rrtype.h>
26

27 28
#include <datasrc/client.h>

29
#include <dns/name.h>
30
#include <exceptions/exceptions.h>
31

32 33 34
#include <map>
#include <set>

35 36 37
namespace isc {
namespace datasrc {

38
/**
39
 * \brief Abstraction of lowlevel database with DNS data
40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
 *
 * This class is defines interface to databases. Each supported database
 * will provide methods for accessing the data stored there in a generic
 * manner. The methods are meant to be low-level, without much or any knowledge
 * about DNS and should be possible to translate directly to queries.
 *
 * On the other hand, how the communication with database is done and in what
 * schema (in case of relational/SQL database) is up to the concrete classes.
 *
 * This class is non-copyable, as copying connections to database makes little
 * sense and will not be needed.
 *
 * \todo Is it true this does not need to be copied? For example the zone
 *     iterator might need it's own copy. But a virtual clone() method might
 *     be better for that than copy constructor.
 *
 * \note The same application may create multiple connections to the same
57 58 59
 *     database, having multiple instances of this class. If the database
 *     allows having multiple open queries at one connection, the connection
 *     class may share it.
60
 */
61
class DatabaseAccessor : boost::noncopyable {
62
public:
63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83
    /**
     * Definitions of the fields as they are required to be filled in
     * by IteratorContext::getNext()
     *
     * When implementing getNext(), the columns array should
     * be filled with the values as described in this enumeration,
     * in this order, i.e. TYPE_COLUMN should be the first element
     * (index 0) of the array, TTL_COLUMN should be the second element
     * (index 1), etc.
     */
    enum RecordColumns {
        TYPE_COLUMN = 0,    ///< The RRType of the record (A/NS/TXT etc.)
        TTL_COLUMN = 1,     ///< The TTL of the record (a
        SIGTYPE_COLUMN = 2, ///< For RRSIG records, this contains the RRTYPE
                            ///< the RRSIG covers. In the current implementation,
                            ///< this field is ignored.
        RDATA_COLUMN = 3,   ///< Full text representation of the record's RDATA
        NAME_COLUMN = 4,    ///< The domain name of this RR
        COLUMN_COUNT = 5    ///< The total number of columns, MUST be value of
                            ///< the largest other element in this enum plus 1.
    };
84

JINMEI Tatuya's avatar
JINMEI Tatuya committed
85 86 87 88
    /**
     * Definitions of the fields to be passed to addRecordToZone().
     *
     * Each derived implementation of addRecordToZone() should expect
JINMEI Tatuya's avatar
JINMEI Tatuya committed
89
     * the "columns" array to be filled with the values as described in this
JINMEI Tatuya's avatar
JINMEI Tatuya committed
90 91 92 93 94
     * enumeration, in this order.
     */
    enum AddRecordColumns {
        ADD_NAME = 0, ///< The owner name of the record (a domain name)
        ADD_REV_NAME = 1, ///< Reversed name of NAME (used for DNSSEC)
95
        ADD_TTL = 2,     ///< The TTL of the record (in numeric form)
JINMEI Tatuya's avatar
JINMEI Tatuya committed
96 97 98 99 100 101 102 103 104 105 106
        ADD_TYPE = 3,    ///< The RRType of the record (A/NS/TXT etc.)
        ADD_SIGTYPE = 4, ///< For RRSIG records, this contains the RRTYPE
                            ///< the RRSIG covers.
        ADD_RDATA = 5,    ///< Full text representation of the record's RDATA
        ADD_COLUMN_COUNT = 6 ///< Number of columns
    };

    /**
     * Definitions of the fields to be passed to deleteRecordInZone().
     *
     * Each derived implementation of deleteRecordInZone() should expect
JINMEI Tatuya's avatar
JINMEI Tatuya committed
107
     * the "params" array to be filled with the values as described in this
JINMEI Tatuya's avatar
JINMEI Tatuya committed
108 109 110 111 112 113 114 115
     * enumeration, in this order.
     */
    enum DeleteRecordParams {
        DEL_NAME = 0, ///< The owner name of the record (a domain name)
        DEL_TYPE = 1, ///< The RRType of the record (A/NS/TXT etc.)
        DEL_RDATA = 2, ///< Full text representation of the record's RDATA
        DEL_PARAM_COUNT = 3 ///< Number of parameters
    };
116

117 118 119 120 121
    /**
     * Operation mode when adding a record diff.
     *
     * This is used as the "operation" parameter value of addRecordDiff().
     */
122
    enum DiffOperation {
JINMEI Tatuya's avatar
JINMEI Tatuya committed
123 124
        DIFF_ADD = 0,           ///< This diff is for adding an RR
        DIFF_DELETE = 1         ///< This diff is for deleting an RR
125 126
    };

JINMEI Tatuya's avatar
JINMEI Tatuya committed
127 128 129 130 131 132 133
    /**
     * Definitions of the fields to be passed to addRecordDiff().
     *
     * Each derived implementation of addRecordDiff() should expect
     * the "params" array to be filled with the values as described in this
     * enumeration, in this order.
     */
134
    enum DiffRecordParams {
JINMEI Tatuya's avatar
JINMEI Tatuya committed
135 136 137 138 139
        DIFF_NAME = 0, ///< The owner name of the record (a domain name)
        DIFF_TYPE = 1, ///< The RRType of the record (A/NS/TXT etc.)
        DIFF_TTL = 2,  ///< The TTL of the record (in numeric form)
        DIFF_RDATA = 3, ///< Full text representation of the record's RDATA
        DIFF_PARAM_COUNT = 4    ///< Number of parameters
140 141
    };

142 143 144 145 146 147
    /**
     * \brief Destructor
     *
     * It is empty, but needs a virtual one, since we will use the derived
     * classes in polymorphic way.
     */
148
    virtual ~DatabaseAccessor() { }
149

150 151 152 153 154 155 156 157 158 159 160
    /**
     * \brief Retrieve a zone identifier
     *
     * This method looks up a zone for the given name in the database. It
     * should match only exact zone name (eg. name is equal to the zone's
     * apex), as the DatabaseClient will loop trough the labels itself and
     * find the most suitable zone.
     *
     * It is not specified if and what implementation of this method may throw,
     * so code should expect anything.
     *
161 162
     * \param name The (fully qualified) domain name of the zone's apex to be
     *             looked up.
163 164 165 166
     * \return The first part of the result indicates if a matching zone
     *     was found. In case it was, the second part is internal zone ID.
     *     This one will be passed to methods finding data in the zone.
     *     It is not required to keep them, in which case whatever might
167
     *     be returned - the ID is only passed back to the database as
168 169
     *     an opaque handle.
     */
170
    virtual std::pair<bool, int> getZone(const std::string& name) const = 0;
171

172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193
    /**
     * \brief This holds the internal context of ZoneIterator for databases
     *
     * While the ZoneIterator implementation from DatabaseClient does all the
     * translation from strings to DNS classes and validation, this class
     * holds the pointer to where the database is at reading the data.
     *
     * It can either hold shared pointer to the connection which created it
     * and have some kind of statement inside (in case single database
     * connection can handle multiple concurrent SQL statements) or it can
     * create a new connection (or, if it is more convenient, the connection
     * itself can inherit both from DatabaseConnection and IteratorContext
     * and just clone itself).
     */
    class IteratorContext : public boost::noncopyable {
    public:
        /**
         * \brief Destructor
         *
         * Virtual destructor, so any descendand class is destroyed correctly.
         */
        virtual ~IteratorContext() { }
Jelte Jansen's avatar
Jelte Jansen committed
194

195 196 197 198
        /**
         * \brief Function to provide next resource record
         *
         * This function should provide data about the next resource record
Jelte Jansen's avatar
Jelte Jansen committed
199
         * from the data that is searched. The data is not converted yet.
200
         *
Jelte Jansen's avatar
Jelte Jansen committed
201 202
         * Depending on how the iterator was constructed, there is a difference
         * in behaviour; for a 'full zone iterator', created with
203 204 205 206
         * getAllRecords(), all COLUMN_COUNT elements of the array are
         * overwritten.
         * For a 'name iterator', created with getRecords(), the column
         * NAME_COLUMN is untouched, since what would be added here is by
Jelte Jansen's avatar
Jelte Jansen committed
207 208
         * definition already known to the caller (it already passes it as
         * an argument to getRecords()).
209
         *
210 211 212 213 214
         * Once this function returns false, any subsequent call to it should
         * result in false.  The implementation of a derived class must ensure
         * it doesn't cause any disruption due to that such as a crash or
         * exception.
         *
Jelte Jansen's avatar
Jelte Jansen committed
215 216
         * \note The order of RRs is not strictly set, but the RRs for single
         * RRset must not be interleaved with any other RRs (eg. RRsets must be
217 218
         * "together").
         *
219
         * \param columns The data will be returned through here. The order
Jelte Jansen's avatar
Jelte Jansen committed
220 221
         *     is specified by the RecordColumns enum, and the size must be
         *     COLUMN_COUNT
222 223
         * \todo Do we consider databases where it is stored in binary blob
         *     format?
224 225 226
         * \throw DataSourceError if there's database-related error. If the
         *     exception (or any other in case of derived class) is thrown,
         *     the iterator can't be safely used any more.
227 228 229
         * \return true if a record was found, and the columns array was
         *         updated. false if there was no more data, in which case
         *         the columns array is untouched.
230
         */
231
        virtual bool getNext(std::string (&columns)[COLUMN_COUNT]) = 0;
232
    };
Jelte Jansen's avatar
Jelte Jansen committed
233

234
    typedef boost::shared_ptr<IteratorContext> IteratorContextPtr;
Jelte Jansen's avatar
Jelte Jansen committed
235

236 237 238
    /**
     * \brief Creates an iterator context for a specific name.
     *
239 240
     * Returns an IteratorContextPtr that contains all records of the
     * given name from the given zone.
241
     *
Jelte Jansen's avatar
Jelte Jansen committed
242
     * The implementation of the iterator that is returned may leave the
243
     * NAME_COLUMN column of the array passed to getNext() untouched, as that
Jelte Jansen's avatar
Jelte Jansen committed
244 245
     * data is already known (it is the same as the name argument here)
     *
246 247 248 249
     * \exception any Since any implementation can be used, the caller should
     *            expect any exception to be thrown.
     *
     * \param name The name to search for. This should be a FQDN.
250
     * \param id The ID of the zone, returned from getZone().
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
251 252 253
     * \param subdomains If set to true, match subdomains of name instead
     *     of name itself. It is used to find empty domains and match
     *     wildcards.
254 255
     * \return Newly created iterator context. Must not be NULL.
     */
256
    virtual IteratorContextPtr getRecords(const std::string& name,
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
257 258
                                          int id,
                                          bool subdomains = false) const = 0;
259

260
    /**
261
     * \brief Creates an iterator context for the whole zone.
262
     *
263 264
     * Returns an IteratorContextPtr that contains all records of the
     * zone with the given zone id.
265
     *
266 267 268 269 270 271
     * Each call to getNext() on the returned iterator should copy all
     * column fields of the array that is passed, as defined in the
     * RecordColumns enum.
     *
     * \exception any Since any implementation can be used, the caller should
     *            expect any exception to be thrown.
272 273 274 275
     *
     * \param id The ID of the zone, returned from getZone().
     * \return Newly created iterator context. Must not be NULL.
     */
276
    virtual IteratorContextPtr getAllRecords(int id) const = 0;
277

278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324
    /**
     * \brief Creates an iterator context for a set of differences.
     *
     * Returns an IteratorContextPtr that contains all difference records for
     * the given zone between two versions of a zone.
     *
     * The difference records are the set of records that would appear in an
     * IXFR serving a request for the difference between two versions of a zone.
     * The records are returned in the same order as they would be in the IXFR.
     * This means that if the the difference between versions of a zone with SOA
     * serial numbers of "start" and "end" is required, and the zone contains
     * the differences between serial number "start" to serial number
     * "intermediate" and from serial number "intermediate" to serial number
     * "end", the returned records will be (in order):
     *
     * \li SOA for serial "start"
     * \li Records removed from the zone between versions "start" and
     *     "intermediate" of the zone.  The order of these is not guaranteed.
     * \li SOA for serial "intermediate"
     * \li Records added to the zone between versions "start" and
     *     "intermediate" of the zone.  The order of these is not guaranteed.
     * \li SOA for serial "intermediate"
     * \li Records removed from the zone between versions "intermediate" and
     *     "end" of the zone.  The order of these is not guaranteed.
     * \li SOA for serial "end"
     * \li Records added to the zone between versions "intermediate" and "end"
     *     of the zone. The order of these is not guaranteed.
     *
     * Note that there is no requirement that "start" be less than "end". Owing
     * to serial number arithmetic, it is entirely possible that a later version
     * of a zone will have a smaller SOA serial number than an earlier version.
     *
     * Each call to getNext() on the returned iterator should copy all
     * column fields of the array that is passed, as defined in the
     * RecordColumns enum.
     *
     * \exception any Since any implementation can be used, the caller should
     *                expect any exception to be thrown.
     *
     * \param id The ID of the zone, returned from getZone().
     * \param start The SOA serial number of the version of the zone from
     *        which the difference sequence should start.
     * \param end The SOA serial number of the version of the zone at which
     *        the difference sequence should end.
     *
     * \return Newly created iterator context. Must not be NULL.
     */
325 326
    virtual IteratorContextPtr
    getDiffs(int id, uint32_t start, uint32_t end) const = 0;
327

JINMEI Tatuya's avatar
JINMEI Tatuya committed
328 329 330 331 332 333 334 335 336 337 338
    /// Start a transaction for updating a zone.
    ///
    /// Each derived class version of this method starts a database
    /// transaction to make updates to the given name of zone (whose class was
    /// specified at the construction of the class).
    ///
    /// If \c replace is true, any existing records of the zone will be
    /// deleted on successful completion of updates (after
    /// \c commitUpdateZone()); if it's false, the existing records will be
    /// intact unless explicitly deleted by \c deleteRecordInZone().
    ///
339
    /// A single \c DatabaseAccessor instance can perform at most one
JINMEI Tatuya's avatar
JINMEI Tatuya committed
340
    /// transaction; a duplicate call to this method before
341 342 343 344 345 346
    /// \c commitUpdateZone() or \c rollbackUpdateZone(), or a call to this
    /// method within another transaction started by \c startTransaction()
    /// will result in a \c DataSourceError exception.
    /// If multiple update attempts need to be performed concurrently (and
    /// if the underlying database allows such operation), separate
    /// \c DatabaseAccessor instance must be created.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374
    ///
    /// \note The underlying database may not allow concurrent updates to
    /// the same database instance even if different "connections" (or
    /// something similar specific to the database implementation) are used
    /// for different sets of updates.  For example, it doesn't seem to be
    /// possible for SQLite3 unless different databases are used.  MySQL
    /// allows concurrent updates to different tables of the same database,
    /// but a specific operation may block others.  As such, this interface
    /// doesn't require derived classes to allow concurrent updates with
    /// multiple \c DatabaseAccessor instances; however, the implementation
    /// is encouraged to do the best for making it more likely to succeed
    /// as long as the underlying database system allows concurrent updates.
    ///
    /// This method returns a pair of \c bool and \c int.  Its first element
    /// indicates whether the given name of zone is found.  If it's false,
    /// the transaction isn't considered to be started; a subsequent call to
    /// this method with an existing zone name should succeed.  Likewise,
    /// if a call to this method results in an exception, the transaction
    /// isn't considered to be started.  Note also that if the zone is not
    /// found this method doesn't try to create a new one in the database.
    /// It must have been created by some other means beforehand.
    ///
    /// The second element is the internal zone ID used for subsequent
    /// updates.  Depending on implementation details of the actual derived
    /// class method, it may be different from the one returned by
    /// \c getZone(); for example, a specific implementation may use a
    /// completely new zone ID when \c replace is true.
    ///
375 376 377
    /// \exception DataSourceError Duplicate call to this method, call to
    /// this method within another transaction, or some internal database
    /// related error.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418
    ///
    /// \param zone_name A string representation of the zone name to be updated
    /// \param replace Whether to replace the entire zone (see above)
    ///
    /// \return A pair of bool and int, indicating whether the specified zone
    /// exists and (if so) the zone ID to be used for the update, respectively.
    virtual std::pair<bool, int> startUpdateZone(const std::string& zone_name,
                                                 bool replace) = 0;

    /// Add a single record to the zone to be updated.
    ///
    /// This method provides a simple interface to insert a new record
    /// (a database "row") to the zone in the update context started by
    /// \c startUpdateZone().  The zone to which the record to be added
    /// is the one specified at the time of the \c startUpdateZone() call.
    ///
    /// A successful call to \c startUpdateZone() must have preceded to
    /// this call; otherwise a \c DataSourceError exception will be thrown.
    ///
    /// The row is defined as a vector of strings that has exactly
    /// ADD_COLUMN_COUNT number of elements.  See AddRecordColumns for
    /// the semantics of each element.
    ///
    /// Derived class methods are not required to check whether the given
    /// values in \c columns are valid in terms of the expected semantics;
    /// in general, it's the caller's responsibility.
    /// For example, TTLs would normally be expected to be a textual
    /// representation of decimal numbers, but this interface doesn't require
    /// the implementation to perform this level of validation.  It may check
    /// the values, however, and in that case if it detects an error it
    /// should throw a \c DataSourceError exception.
    ///
    /// Likewise, derived class methods are not required to detect any
    /// duplicate record that is already in the zone.
    ///
    /// \note The underlying database schema may not have a trivial mapping
    /// from this style of definition of rows to actual database records.
    /// It's the implementation's responsibility to implement the mapping
    /// in the actual derived method.
    ///
    /// \exception DataSourceError Invalid call without starting a transaction,
419
    /// or other internal database error.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
420
    ///
421
    /// \param columns An array of strings that defines a record to be added
JINMEI Tatuya's avatar
JINMEI Tatuya committed
422
    /// to the zone.
423 424
    virtual void addRecordToZone(
        const std::string (&columns)[ADD_COLUMN_COUNT]) = 0;
JINMEI Tatuya's avatar
JINMEI Tatuya committed
425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455

    /// Delete a single record from the zone to be updated.
    ///
    /// This method provides a simple interface to delete a record
    /// (a database "row") from the zone in the update context started by
    /// \c startUpdateZone().  The zone from which the record to be deleted
    /// is the one specified at the time of the \c startUpdateZone() call.
    ///
    /// A successful call to \c startUpdateZone() must have preceded to
    /// this call; otherwise a \c DataSourceError exception will be thrown.
    ///
    /// The record to be deleted is specified by a vector of strings that has
    /// exactly DEL_PARAM_COUNT number of elements.  See DeleteRecordParams
    /// for the semantics of each element.
    ///
    /// \note In IXFR, TTL may also be specified, but we intentionally
    /// ignore that in this interface, because it's not guaranteed
    /// that all records have the same TTL (unlike the RRset
    /// assumption) and there can even be multiple records for the
    /// same name, type and rdata with different TTLs.  If we only
    /// delete one of them, subsequent lookup will still return a
    /// positive answer, which would be confusing.  It's a higher
    /// layer's responsibility to check if there is at least one
    /// record in the database that has the given TTL.
    ///
    /// Like \c addRecordToZone, derived class methods are not required to
    /// validate the semantics of the given parameters or to check if there
    /// is a record that matches the specified parameter; if there isn't
    /// it simply ignores the result.
    ///
    /// \exception DataSourceError Invalid call without starting a transaction,
456
    /// or other internal database error.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
457
    ///
458
    /// \param params An array of strings that defines a record to be deleted
JINMEI Tatuya's avatar
JINMEI Tatuya committed
459 460
    /// from the zone.
    virtual void deleteRecordInZone(
461
        const std::string (&params)[DEL_PARAM_COUNT]) = 0;
JINMEI Tatuya's avatar
JINMEI Tatuya committed
462

463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482
    /// Start a general transaction.
    ///
    /// Each derived class version of this method starts a database
    /// transaction in a way specific to the database details.  Any subsequent
    /// operations on the accessor are guaranteed to be not susceptible to
    /// any update attempts made during the transaction.  The transaction
    /// must be terminated by either \c commit() or \c rollback().
    ///
    /// In practice, this transaction is intended to be used to perform
    /// a set of atomic reads and work as a read-only lock.  So, in many
    /// cases \c commit() and \c rollback() will have the same effect.
    ///
    /// This transaction cannot coexist with an update transaction started
    /// by \c startUpdateZone().  Such an attempt will result in
    /// \c DataSourceError.
    ///
    /// \exception DataSourceError An attempt of nested transaction, or some
    /// internal database related error.
    virtual void startTransaction() = 0;

483
    /// Commit a transaction.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
484
    ///
485 486
    /// This method completes a transaction started by \c startTransaction
    /// or \c startUpdateZone.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
487
    ///
488
    /// A successful call to one of the "start" methods must have preceded to
JINMEI Tatuya's avatar
JINMEI Tatuya committed
489 490 491 492 493 494 495 496 497 498 499 500 501 502 503
    /// this call; otherwise a \c DataSourceError exception will be thrown.
    /// Once this method successfully completes, the transaction isn't
    /// considered to exist any more.  So a new transaction can now be
    /// started.  On the other hand, a duplicate call to this method after
    /// a successful completion of it is invalid and should result in
    /// a \c DataSourceError exception.
    ///
    /// If some internal database error happens, a \c DataSourceError
    /// exception must be thrown.  In that case the transaction is still
    /// considered to be valid; the caller must explicitly rollback it
    /// or (if it's confident that the error is temporary) try to commit it
    /// again.
    ///
    /// \exception DataSourceError Call without a transaction, duplicate call
    /// to the method or internal database error.
504
    virtual void commit() = 0;
JINMEI Tatuya's avatar
JINMEI Tatuya committed
505

506
    /// Rollback any changes in a transaction made so far.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
507
    ///
508 509 510 511
    /// This method rollbacks a transaction started by \c startTransaction or
    /// \c startUpdateZone.  When it succeeds (it normally should, but see
    /// below), the underlying database should be reverted to the point
    /// before performing the corresponding "start" method.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
512
    ///
513
    /// A successful call to one of the "start" method must have preceded to
JINMEI Tatuya's avatar
JINMEI Tatuya committed
514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529
    /// this call; otherwise a \c DataSourceError exception will be thrown.
    /// Once this method successfully completes, the transaction isn't
    /// considered to exist any more.  So a new transaction can now be
    /// started.  On the other hand, a duplicate call to this method after
    /// a successful completion of it is invalid and should result in
    /// a \c DataSourceError exception.
    ///
    /// Normally this method should not fail.  But it may not always be
    /// possible to guarantee it depending on the characteristics of the
    /// underlying database system.  So this interface doesn't require the
    /// actual implementation for the error free property.  But if a specific
    /// implementation of this method can fail, it is encouraged to document
    /// when that can happen with its implication.
    ///
    /// \exception DataSourceError Call without a transaction, duplicate call
    /// to the method or internal database error.
530
    virtual void rollback() = 0;
JINMEI Tatuya's avatar
JINMEI Tatuya committed
531

JINMEI Tatuya's avatar
JINMEI Tatuya committed
532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587
    /// Install a single RR diff in difference sequences for zone update.
    ///
    /// This method inserts parameters of an update operation for a single RR
    /// (either adding or deleting one) in the underlying database.
    /// (These parameters would normally be a separate database table, but
    /// actual realization can differ in specific implementations).
    /// The information given via this method generally corresponds to either
    /// a single call to \c addRecordToZone() or \c deleteRecordInZone(),
    /// and this method is expected to be called immediately after (or before)
    /// a call to either of those methods.
    ///
    /// Note, however, that this method passes more detailed information
    /// than those update methods: it passes "serial", even if the diff
    /// is not for the SOA RR; it passes TTL for a diff that deletes an RR
    /// while in \c deleteRecordInZone() it's omitted.  This is because
    /// the stored diffs are expected to be retrieved in the form that
    /// \c getRecordDiffs() is expected to meet.  This means if the caller
    /// wants to use this method with other update operations, it must
    /// ensure the additional information is ready when this method is called.
    ///
    /// \note \c getRecordDiffs() is not yet implemented.
    ///
    /// The caller of this method must ensure that the added diffs via
    /// this method in a single transaction form an IXFR-style difference
    /// sequences: Each difference sequence is a sequence of RRs:
    /// an older version of SOA (to be deleted), zero or more other deleted
    /// RRs, the post-transaction SOA (to be added), and zero or more other
    /// added RRs.  So, for example, the first call to this method in a
    /// transaction must always be deleting an SOA.  Also, the \c serial
    /// parameter must be equal to the value of the serial field of the
    /// SOA that was last added or deleted (if the call is to add or delete
    /// an SOA RR, \c serial must be identical to the serial of that SOA).
    /// The underlying derived class implementation may or may not check
    /// this condition, but if the caller doesn't meet the condition
    /// a subsequent call to \c getRecordDiffs() will not work as expected.
    ///
    /// Any call to this method must be in a transaction, and, for now,
    /// it must be a transaction triggered by \c startUpdateZone() (that is,
    /// it cannot be a transaction started by \c startTransaction()).
    /// All calls to this method are considered to be part of an atomic
    /// transaction: Until \c commit() is performed, the added diffs are
    /// not visible outside the transaction; if \c rollback() is performed,
    /// all added diffs are canceled; and the added sequences are not
    /// affected by any concurrent attempt of adding diffs (conflict resolution
    /// is up to the database implementation).
    ///
    /// Also for now, all diffs are assumed to be for the zone that is
    /// being updated in the context of \c startUpdateZone().  So the
    /// \c zone_id parameter must be identical to the zone ID returned by
    /// \c startUpdateZone().
    ///
    /// In a future version we may loosen this condition so that diffs can be
    /// added in a generic transaction and may not even have to belong to
    /// a single zone.  For this possible extension \c zone_id parameter is
    /// included even if it's redundant under the current restriction.
    ///
588 589 590 591
    /// The support for adding (or retrieving) diffs is optional; if it's
    /// not supported in a specific data source, this method for the
    /// corresponding derived class will throw an \c NotImplemented exception.
    ///
JINMEI Tatuya's avatar
JINMEI Tatuya committed
592 593 594
    /// \exception DataSourceError Invalid call without starting a transaction,
    /// zone ID doesn't match the zone being updated, or other internal
    /// database error.
595 596
    /// \exception NotImplemented Adding diffs is not supported in the
    /// data source.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
597 598 599 600 601 602 603
    /// \exception Other The concrete derived method may throw other
    /// data source specific exceptions.
    ///
    /// \param zone_id The zone for the diff to be added.
    /// \param serial The SOA serial to which the diff belongs.
    /// \param operation Either \c DIFF_ADD or \c DIFF_DELETE.
    /// \param params An array of strings that defines a record for the diff.
604 605 606 607
    virtual void addRecordDiff(
        int zone_id, uint32_t serial, DiffOperation operation,
        const std::string (&params)[DIFF_PARAM_COUNT]) = 0;

608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634
    /// Clone the accessor with the same configuration.
    ///
    /// Each derived class implementation of this method will create a new
    /// accessor of the same derived class with the same configuration
    /// (such as the database server address) as that of the caller object
    /// and return it.
    ///
    /// Note that other internal states won't be copied to the new accessor
    /// even though the name of "clone" may indicate so.  For example, even
    /// if the calling accessor is in the middle of a update transaction,
    /// the new accessor will not start a transaction to trace the same
    /// updates.
    ///
    /// The intended use case of cloning is to create a separate context
    /// where a specific set of database operations can be performed
    /// independently from the original accessor.  The updater will use it
    /// so that multiple updaters can be created concurrently even if the
    /// underlying database system doesn't allow running multiple transactions
    /// in a single database connection.
    ///
    /// The underlying database system may not support the functionality
    /// that would be needed to implement this method.  For example, it
    /// may not allow a single thread (or process) to have more than one
    /// database connections.  In such a case the derived class implementation
    /// should throw a \c DataSourceError exception.
    ///
    /// \return A shared pointer to the cloned accessor.
635
    virtual boost::shared_ptr<DatabaseAccessor> clone() = 0;
636 637

    /**
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
638 639 640 641 642 643 644 645 646 647 648
     * \brief Returns a string identifying this dabase backend
     *
     * The returned string is mainly intended to be used for
     * debugging/logging purposes.
     *
     * Any implementation is free to choose the exact string content,
     * but it is advisable to make it a name that is distinguishable
     * from the others.
     *
     * \return the name of the database
     */
649
    virtual const std::string& getDBName() const = 0;
650 651

    /**
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
652
     * \brief It returns the previous name in DNSSEC order.
653 654 655 656
     *
     * This is used in DatabaseClient::findPreviousName and does more
     * or less the real work, except for working on strings.
     *
657
     * \param rname The name to ask for previous of, in reversed form.
658 659 660 661
     *     We use the reversed form (see isc::dns::Name::reverse),
     *     because then the case insensitive order of string representation
     *     and the DNSSEC order correspond (eg. org.example.a is followed
     *     by org.example.a.b which is followed by org.example.b, etc).
662
     * \param zone_id The zone to look through.
663 664
     * \return The previous name.
     * \note This function must return previous name even in case
665
     *     the queried rname does not exist in the zone.
666 667 668
     * \note This method must skip under-the-zone-cut data (glue data).
     *     This might be implemented by looking for NSEC records (as glue
     *     data don't have them) in the zone or in some other way.
669 670
     *
     * \throw DataSourceError if there's a problem with the database.
671 672 673 674
     * \throw NotImplemented if this database doesn't support DNSSEC
     *     or there's no previous name for the queried one (the NSECs
     *     might be missing or the queried name is less or equal the
     *     apex of the zone).
675 676
     */
    virtual std::string findPreviousName(int zone_id,
677
                                         const std::string& rname) const = 0;
678 679
};

680 681 682 683 684
/**
 * \brief Concrete data source client oriented at database backends.
 *
 * This class (together with corresponding versions of ZoneFinder,
 * ZoneIterator, etc.) translates high-level data source queries to
685
 * low-level calls on DatabaseAccessor. It calls multiple queries
686
 * if necessary and validates data from the database, allowing the
687
 * DatabaseAccessor to be just simple translation to SQL/other
688 689 690 691
 * queries to database.
 *
 * While it is possible to subclass it for specific database in case
 * of special needs, it is not expected to be needed. This should just
692
 * work as it is with whatever DatabaseAccessor.
693
 */
694 695
class DatabaseClient : public DataSourceClient {
public:
696 697 698
    /**
     * \brief Constructor
     *
699
     * It initializes the client with a database via the given accessor.
700
     *
701
     * \exception isc::InvalidParameter if accessor is NULL. It might throw
702 703
     * standard allocation exception as well, but doesn't throw anything else.
     *
704
     * \param rrclass The RR class of the zones that this client will handle.
705 706 707
     * \param accessor The accessor to the database to use to get data.
     *  As the parameter suggests, the client takes ownership of the accessor
     *  and will delete it when itself deleted.
708
     */
709
    DatabaseClient(isc::dns::RRClass rrclass,
710
                   boost::shared_ptr<DatabaseAccessor> accessor);
711

712 713 714 715 716
    /**
     * \brief Corresponding ZoneFinder implementation
     *
     * The zone finder implementation for database data sources. Similarly
     * to the DatabaseClient, it translates the queries to methods of the
717
     * database.
718 719 720 721 722 723 724 725 726 727 728 729 730 731
     *
     * Application should not come directly in contact with this class
     * (it should handle it trough generic ZoneFinder pointer), therefore
     * it could be completely hidden in the .cc file. But it is provided
     * to allow testing and for rare cases when a database needs slightly
     * different handling, so it can be subclassed.
     *
     * Methods directly corresponds to the ones in ZoneFinder.
     */
    class Finder : public ZoneFinder {
    public:
        /**
         * \brief Constructor
         *
732
         * \param database The database (shared with DatabaseClient) to
733 734
         *     be used for queries (the one asked for ID before).
         * \param zone_id The zone ID which was returned from
735
         *     DatabaseAccessor::getZone and which will be passed to further
736
         *     calls to the database.
737 738 739
         * \param origin The name of the origin of this zone. It could query
         *     it from database, but as the DatabaseClient just searched for
         *     the zone using the name, it should have it.
740
         */
741 742
        Finder(boost::shared_ptr<DatabaseAccessor> database, int zone_id,
               const isc::dns::Name& origin);
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
743 744
        // The following three methods are just implementations of inherited
        // ZoneFinder's pure virtual methods.
745 746
        virtual isc::dns::Name getOrigin() const;
        virtual isc::dns::RRClass getClass() const;
747 748 749

        /**
         * \brief Find an RRset in the datasource
750
         *
Jelte Jansen's avatar
Jelte Jansen committed
751 752 753 754 755 756 757 758 759 760 761
         * Searches the datasource for an RRset of the given name and
         * type. If there is a CNAME at the given name, the CNAME rrset
         * is returned.
         * (this implementation is not complete, and currently only
         * does full matches, CNAMES, and the signatures for matches and
         * CNAMEs)
         * \note target was used in the original design to handle ANY
         *       queries. This is not implemented yet, and may use
         *       target again for that, but it might also use something
         *       different. It is left in for compatibility at the moment.
         * \note options are ignored at this moment
Jelte Jansen's avatar
Jelte Jansen committed
762
         *
763 764 765 766 767 768 769 770 771 772 773 774 775 776
         * \note Maybe counter intuitively, this method is not a const member
         * function.  This is intentional; some of the underlying implementations
         * are expected to use a database backend, and would internally contain
         * some abstraction of "database connection".  In the most strict sense
         * any (even read only) operation might change the internal state of
         * such a connection, and in that sense the operation cannot be considered
         * "const".  In order to avoid giving a false sense of safety to the
         * caller, we indicate a call to this method may have a surprising
         * side effect.  That said, this view may be too strict and it may
         * make sense to say the internal database connection doesn't affect
         * external behavior in terms of the interface of this method.  As
         * we gain more experiences with various kinds of backends we may
         * revisit the constness.
         *
Jelte Jansen's avatar
Jelte Jansen committed
777 778 779 780 781 782 783 784
         * \exception DataSourceError when there is a problem reading
         *                            the data from the dabase backend.
         *                            This can be a connection, code, or
         *                            data (parse) error.
         *
         * \param name The name to find
         * \param type The RRType to find
         * \param target Unused at this moment
785 786
         * \param options Options about how to search.
         *     See ZoneFinder::FindOptions.
787
         */
788 789 790
        virtual FindResult find(const isc::dns::Name& name,
                                const isc::dns::RRType& type,
                                isc::dns::RRsetList* target = NULL,
Jelte Jansen's avatar
Jelte Jansen committed
791
                                const FindOptions options = FIND_DEFAULT);
Jelte Jansen's avatar
Jelte Jansen committed
792

793 794 795 796 797 798
        /**
         * \brief Implementation of ZoneFinder::findPreviousName method.
         */
        virtual isc::dns::Name findPreviousName(const isc::dns::Name& query)
            const;

799 800 801 802 803 804 805 806
        /**
         * \brief The zone ID
         *
         * This function provides the stored zone ID as passed to the
         * constructor. This is meant for testing purposes and normal
         * applications shouldn't need it.
         */
        int zone_id() const { return (zone_id_); }
807

808
        /**
809
         * \brief The database accessor.
810
         *
811
         * This function provides the database accessor stored inside as
812 813 814
         * passed to the constructor. This is meant for testing purposes and
         * normal applications shouldn't need it.
         */
815 816
        const DatabaseAccessor& getAccessor() const {
            return (*accessor_);
817
        }
818

819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
        /// \brief Search result of \c findDelegationPoint().
        ///
        /// This is a tuple combining the result of the search - a status code
        /// and a pointer to the RRset found - together with additional
        /// information needed for subsequent processing, an indication of
        /// the first NS RRset found in the search and the number of labels
        /// in the last non-empty domain encountered in the search.  It is
        /// used by \c findDelegationPoint().
        ///
        /// The last two items are located naturally in the search and although
        /// not strictly part of the result, they are passed back to avoid
        /// another (duplicate) search later in the processing.
        ///
        /// Note that the code and rrset elements are the same as that in
        /// the \c ZoneFinder::FindResult struct: this structure could be
        /// derived from that one, but as it is used just once in the code and
        /// will never be treated as a \c FindResult, the obscurity involved in
        /// deriving it from a parent class was deemed not worthwhile.
        struct DelegationSearchResult {
            DelegationSearchResult(const ZoneFinder::Result param_code,
                                   const isc::dns::RRsetPtr param_rrset,
                                   const isc::dns::RRsetPtr param_ns,
                                   size_t param_last_known) :
                                   code(param_code), rrset(param_rrset),
                                   first_ns(param_ns),
                                   last_known(param_last_known)
            {}
            const ZoneFinder::Result code;      ///< Result code
            const isc::dns::RRsetPtr rrset;     ///< Pointer to RRset found
            const isc::dns::RRsetPtr first_ns;  ///< Pointer to first NS found
            const size_t last_known; ///< No. labels in last non-empty domain
        };

852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877
        /// \brief Search result of \c findWildcard().
        ///
        /// This is a tuple combining the result of the search - a status code
        /// and a pointer to the RRset found - together with additional
        /// information needed for subsequent processing: if there is not a
        /// match for the data sought, then whether there is no match for the
        /// wildcard or where there is a match, but no RRs of the type
        /// requested.
        ///
        /// Note that the code and rrset elements are the same as that in
        /// the \c ZoneFinder::FindResult struct: this structure could be
        /// derived from that one, but as it is used just once in the code and
        /// will never be treated as a \c FindResult, the obscurity involved in
        /// deriving it from a parent class was deemed not worthwhile.
        struct WildcardSearchResult {
            WildcardSearchResult(const ZoneFinder::Result param_code,
                                 const isc::dns::RRsetPtr param_rrset,
                                 const bool param_found) :
                                 code(param_code), rrset(param_rrset),
                                 records_found(param_found)
            {}
            const ZoneFinder::Result code;      ///< Result code
            const isc::dns::RRsetPtr rrset;     ///< Pointer to RRset found
            const bool records_found;           ///< true => NXRRSET
        };

878
    private:
879
        boost::shared_ptr<DatabaseAccessor> accessor_;
880
        const int zone_id_;
881
        const isc::dns::Name origin_;
882 883 884 885 886 887
        //
        /// \brief Shortcut name for the result of getRRsets
        typedef std::pair<bool, std::map<dns::RRType, dns::RRsetPtr> >
            FoundRRsets;
        /// \brief Just shortcut for set of types
        typedef std::set<dns::RRType> WantedTypes;
888

889 890 891 892 893 894 895 896 897 898 899 900
        /**
         * \brief Searches database for RRsets of one domain.
         *
         * This method scans RRs of single domain specified by name and
         * extracts any RRsets found and requested by parameters.
         *
         * It is used internally by find(), because it is called multiple
         * times (usually with different domains).
         *
         * \param name Which domain name should be scanned.
         * \param types List of types the caller is interested in.
         * \param check_ns If this is set to true, it checks nothing lives
901
         *     together with NS record (with few little exceptions, like RRSIG
902 903 904 905 906 907 908 909 910 911 912 913 914 915
         *     or NSEC). This check is meant for non-apex NS records.
         * \param construct_name If this is NULL, the resulting RRsets have
         *     their name set to name. If it is not NULL, it overrides the name
         *     and uses this one (this can be used for wildcard synthesized
         *     records).
         * \return A pair, where the first element indicates if the domain
         *     contains any RRs at all (not only the requested, it may happen
         *     this is set to true, but the second part is empty). The second
         *     part is map from RRtypes to RRsets of the corresponding types.
         *     If the RRset is not present in DB, the RRtype is not there at
         *     all (so you'll not find NULL pointer in the result).
         * \throw DataSourceError If there's a low-level error with the
         *     database or the database contains bad data.
         */
916 917 918
        FoundRRsets getRRsets(const std::string& name,
                              const WantedTypes& types, bool check_ns,
                              const std::string* construct_name = NULL);
919 920 921 922 923 924 925 926

        /**
         * \brief Find delegation point
         *
         * Given a name, searches through the superdomains from the origin
         * down, searching for a point that indicates a delegation (i.e. an
         * NS record or a DNAME).
         *
927 928 929 930 931 932 933 934 935 936 937 938 939 940 941
         * The method operates in two modes, non-glue-ok and glue-ok modes:
         *
         * In non-glue-ok mode, the search is made purely for the NS or DNAME
         * RR.  The zone is searched from the origin down looking  for one
         * of these RRTypes (and ignoring the NS records at the zone origin).
         * A status is returned indicating what is found: DNAME, DELEGATION
         * of SUCCESS, the last indicating that nothing was found, together
         * with a pointer to the relevant RR.
         *
         * In glue-ok mode, the first NS encountered in the search (apart from
         * the NS at the zone apex) is remembered but otherwise NS records are
         * ignored and the search attempts to find a DNAME.  The result is
         * returned in the same format, along with a pointer to the first non-
         * apex NS (if found).
         *
942
         * \param name The name to find
943
         * \param options Options about how to search. See the documentation for
944 945 946 947 948 949 950 951 952 953
         *        ZoneFinder::FindOptions.
         *
         * \return Tuple holding the result of the search - the RRset of the
         *         delegation point and the type of the point (DELEGATION or
         *         DNAME) - and associated information.  This latter item
         *         comprises two pieces of data: a pointer to the highest
         *         encountered NS, and the number of labels in the last known
         *         non-empty domain.  The associated information is found as
         *         a natural part of the search for the delegation point and
         *         is used later in the find() processing; it is passed back
954
         *         to avoid the need to perform a second search to obtain it.
955 956 957
         */
        DelegationSearchResult
        findDelegationPoint(const isc::dns::Name& name,
958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
                            const FindOptions options);

        /**
         * \brief Find wildcard match
         *
         * Having found that the name is not an empty non-terminal, this
         * searches the zone for for wildcards that match the name.
         *
         * It searches superdomains of the name from the zone origin down
         * looking for a wildcard in the zone that matches the name.  There
         * are several cases to consider:
         *
         * - If the previous search for a delegation point has found that
         *   there is an NS at the superdomain of the point at which the
         *   wildcard is found, the delegation is returned.
         * - If there is a match to the name, an appropriate status is
         *   returned (match on requested type, delegation, cname, or just
         *   the indication of a match but no RRs relevant to the query).
         * - If the match is to an non-empty non-terminal wildcard, a
         *   wildcard NXRRSET is returned.
         *
         * Note that if DNSSEC is enabled for the search and the zone uses
         * NSEC for authenticated denial of existence, the search may
         * return NSEC records.
         *
         * \param name The name to find
         * \param type The RRType to find
         * \param options Options about how to search. See the documentation
         *        for ZoneFinder::FindOptions.
         * \param first_ns A pointer to the first NS found in a search for
         *        the name (will only be non-null in glue-ok mode).
         * \param last_known the number of labels in the last known non-empty
         *        domain in the name.
         *
         * \return Tuple holding the result of the search - the RRset of the
         *         wildcard records matching the name, together with a status
         *         indicating the match type (e.g. CNAME at the wildcard
         *         match, no RRs of the requested type at the wildcard,
         *         success due to an exact match).  Also returned if there
         *         is no match is an indication as to whether there was an
         *         NXDOMAIN or an NXRRSET.
         */
        WildcardSearchResult
        findWildcardMatch(const isc::dns::Name& name,
                     const isc::dns::RRType& type, const FindOptions options,
                     isc::dns::RRsetPtr& first_ns, size_t last_known);
1004

1005 1006 1007 1008 1009 1010 1011 1012 1013
        /**
         * \brief Checks if something lives below this domain.
         *
         * This looks if there's any subdomain of the given name. It can be
         * used to test if domain is empty non-terminal.
         *
         * \param name The domain to check.
         */
        bool hasSubdomains(const std::string& name);
1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030

        /**
         * \brief Get the NSEC covering a name.
         *
         * This one calls findPreviousName on the given name and extracts an NSEC
         * record on the result. It handles various error cases. The method exists
         * to share code present at more than one location.
         */
        dns::RRsetPtr findNSECCover(const dns::Name& name);

        /**
         * \brief Convenience type shortcut.
         *
         * To find stuff in the result of getRRsets.
         */
        typedef std::map<dns::RRType, dns::RRsetPtr>::const_iterator
            FoundIterator;
1031
    };
1032

1033 1034 1035
    /**
     * \brief Find a zone in the database
     *
1036
     * This queries database's getZone to find the best matching zone.
1037 1038 1039 1040
     * It will propagate whatever exceptions are thrown from that method
     * (which is not restricted in any way).
     *
     * \param name Name of the zone or data contained there.
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
1041 1042 1043 1044 1045
     * \return FindResult containing the code and an instance of Finder, if
     *     anything is found. However, application should not rely on the
     *     ZoneFinder being instance of Finder (possible subclass of this class
     *     may return something else and it may change in future versions), it
     *     should use it as a ZoneFinder only.
1046
     */
1047
    virtual FindResult findZone(const isc::dns::Name& name) const;
1048

1049 1050 1051 1052 1053 1054 1055 1056 1057 1058
    /**
     * \brief Get the zone iterator
     *
     * The iterator allows going through the whole zone content. If the
     * underlying DatabaseConnection is implemented correctly, it should
     * be possible to have multiple ZoneIterators at once and query data
     * at the same time.
     *
     * \exception DataSourceError if the zone doesn't exist.
     * \exception isc::NotImplemented if the underlying DatabaseConnection
1059 1060
     *     doesn't implement iteration. But in case it is not implemented
     *     and the zone doesn't exist, DataSourceError is thrown.
1061 1062 1063
     * \exception Anything else the underlying DatabaseConnection might
     *     want to throw.
     * \param name The origin of the zone to iterate.
1064 1065 1066 1067 1068 1069
     * \param separate_rrs If true, the iterator will return each RR as a
     *                     new RRset object. If false, the iterator will
     *                     combine consecutive RRs with the name and type
     *                     into 1 RRset. The capitalization of the RRset will
     *                     be that of the first RR read, and TTLs will be
     *                     adjusted to the lowest one found.
1070 1071
     * \return Shared pointer to the iterator (it will never be NULL)
     */
1072
    virtual ZoneIteratorPtr getIterator(const isc::dns::Name& name,
1073
                                        bool separate_rrs = false) const;
Jelte Jansen's avatar
Jelte Jansen committed
1074

1075 1076 1077 1078
    /// This implementation internally clones the accessor from the one
    /// used in the client and starts a separate transaction using the cloned
    /// accessor.  The returned updater will be able to work separately from
    /// the original client.
1079
    virtual ZoneUpdaterPtr getUpdater(const isc::dns::Name& name,
1080 1081
                                      bool replace,
                                      bool journaling = false) const;
1082

1083
private:
1084 1085 1086
    /// \brief The RR class that this client handles.
    const isc::dns::RRClass rrclass_;

1087 1088
    /// \brief The accessor to our database.
    const boost::shared_ptr<DatabaseAccessor> accessor_;
1089 1090 1091 1092 1093
};

}
}

1094 1095 1096 1097 1098
#endif  // __DATABASE_DATASRC_H

// Local Variables:
// mode: c++
// End: