database.h 33.7 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 21
#include <boost/scoped_ptr.hpp>

22
#include <dns/rrclass.h>
23 24
#include <dns/rrclass.h>
#include <dns/rrset.h>
25

26 27
#include <datasrc/client.h>

28
#include <dns/name.h>
29
#include <exceptions/exceptions.h>
30

31 32 33
namespace isc {
namespace datasrc {

34
/**
35
 * \brief Abstraction of lowlevel database with DNS data
36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
 *
 * 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
53 54 55
 *     database, having multiple instances of this class. If the database
 *     allows having multiple open queries at one connection, the connection
 *     class may share it.
56
 */
57
class DatabaseAccessor : boost::noncopyable {
58
public:
59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
    /**
     * 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.
    };
80

JINMEI Tatuya's avatar
JINMEI Tatuya committed
81 82 83 84 85 86 87 88 89 90
    /**
     * Definitions of the fields to be passed to addRecordToZone().
     *
     * Each derived implementation of addRecordToZone() should expect
     * the "columns" vector to be filled with the values as described in this
     * 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)
91
        ADD_TTL = 2,     ///< The TTL of the record (in numeric form)
JINMEI Tatuya's avatar
JINMEI Tatuya committed
92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
        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
     * the "params" vector to be filled with the values as described in this
     * 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
    };
112

113 114 115 116 117 118
    /**
     * \brief Destructor
     *
     * It is empty, but needs a virtual one, since we will use the derived
     * classes in polymorphic way.
     */
119
    virtual ~DatabaseAccessor() { }
120

121 122 123 124 125 126 127 128 129 130 131
    /**
     * \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.
     *
132 133
     * \param name The (fully qualified) domain name of the zone's apex to be
     *             looked up.
134 135 136 137
     * \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
138
     *     be returned - the ID is only passed back to the database as
139 140
     *     an opaque handle.
     */
141
    virtual std::pair<bool, int> getZone(const std::string& name) const = 0;
142

143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
    /**
     * \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
165

166 167 168 169
        /**
         * \brief Function to provide next resource record
         *
         * This function should provide data about the next resource record
Jelte Jansen's avatar
Jelte Jansen committed
170
         * from the data that is searched. The data is not converted yet.
171
         *
Jelte Jansen's avatar
Jelte Jansen committed
172 173
         * Depending on how the iterator was constructed, there is a difference
         * in behaviour; for a 'full zone iterator', created with
174 175 176 177
         * 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
178 179
         * definition already known to the caller (it already passes it as
         * an argument to getRecords()).
180
         *
181 182 183 184 185
         * 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
186 187
         * \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
188 189
         * "together").
         *
190
         * \param columns The data will be returned through here. The order
Jelte Jansen's avatar
Jelte Jansen committed
191 192
         *     is specified by the RecordColumns enum, and the size must be
         *     COLUMN_COUNT
193 194
         * \todo Do we consider databases where it is stored in binary blob
         *     format?
195 196 197
         * \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.
198 199 200
         * \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.
201
         */
202
        virtual bool getNext(std::string (&columns)[COLUMN_COUNT]) = 0;
203
    };
Jelte Jansen's avatar
Jelte Jansen committed
204

205
    typedef boost::shared_ptr<IteratorContext> IteratorContextPtr;
Jelte Jansen's avatar
Jelte Jansen committed
206

207 208 209
    /**
     * \brief Creates an iterator context for a specific name.
     *
210 211
     * Returns an IteratorContextPtr that contains all records of the
     * given name from the given zone.
212
     *
Jelte Jansen's avatar
Jelte Jansen committed
213
     * The implementation of the iterator that is returned may leave the
214
     * NAME_COLUMN column of the array passed to getNext() untouched, as that
Jelte Jansen's avatar
Jelte Jansen committed
215 216
     * data is already known (it is the same as the name argument here)
     *
217 218 219 220
     * \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.
221
     * \param id The ID of the zone, returned from getZone().
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
222 223 224
     * \param subdomains If set to true, match subdomains of name instead
     *     of name itself. It is used to find empty domains and match
     *     wildcards.
225 226
     * \return Newly created iterator context. Must not be NULL.
     */
227
    virtual IteratorContextPtr getRecords(const std::string& name,
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
228 229
                                          int id,
                                          bool subdomains = false) const = 0;
230

231
    /**
232
     * \brief Creates an iterator context for the whole zone.
233
     *
234 235
     * Returns an IteratorContextPtr that contains all records of the
     * zone with the given zone id.
236
     *
237 238 239 240 241 242
     * 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.
243 244 245 246
     *
     * \param id The ID of the zone, returned from getZone().
     * \return Newly created iterator context. Must not be NULL.
     */
247
    virtual IteratorContextPtr getAllRecords(int id) const = 0;
248

JINMEI Tatuya's avatar
JINMEI Tatuya committed
249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337
    /// 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().
    ///
    /// A single \c DatabaseAccessor instance can perform at most one update
    /// transaction; a duplicate call to this method before
    /// \c commitUpdateZone() or \c rollbackUpdateZone() 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.
    ///
    /// \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.
    ///
    /// \exception DataSourceError Duplicate call to this method, or some
    /// internal database related error.
    ///
    /// \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,
338
    /// or other internal database error.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
339
    ///
340
    /// \param columns An array of strings that defines a record to be added
JINMEI Tatuya's avatar
JINMEI Tatuya committed
341
    /// to the zone.
342 343
    virtual void addRecordToZone(
        const std::string (&columns)[ADD_COLUMN_COUNT]) = 0;
JINMEI Tatuya's avatar
JINMEI Tatuya committed
344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374

    /// 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,
375
    /// or other internal database error.
JINMEI Tatuya's avatar
JINMEI Tatuya committed
376
    ///
377
    /// \param params An array of strings that defines a record to be deleted
JINMEI Tatuya's avatar
JINMEI Tatuya committed
378 379
    /// from the zone.
    virtual void deleteRecordInZone(
380
        const std::string (&params)[DEL_PARAM_COUNT]) = 0;
JINMEI Tatuya's avatar
JINMEI Tatuya committed
381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431

    /// Commit updates to the zone.
    ///
    /// This method completes a transaction of making updates to the zone
    /// in the context started by startUpdateZone.
    ///
    /// A successful call to \c startUpdateZone() must have preceded to
    /// 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.
    virtual void commitUpdateZone() = 0;

    /// Rollback updates to the zone made so far.
    ///
    /// This method rollbacks a transaction of making updates to the zone
    /// in the context started by startUpdateZone.  When it succeeds
    /// (it normally should, but see below), the underlying database should
    /// be reverted to the point before performing the corresponding
    /// \c startUpdateZone().
    ///
    /// A successful call to \c startUpdateZone() must have preceded to
    /// 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.
    virtual void rollbackUpdateZone() = 0;

432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458
    /// 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.
459
    virtual boost::shared_ptr<DatabaseAccessor> clone() = 0;
460 461

    /**
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
462 463 464 465 466 467 468 469 470 471 472
     * \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
     */
473
    virtual const std::string& getDBName() const = 0;
474 475
};

476 477 478 479 480
/**
 * \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
481
 * low-level calls on DatabaseAccessor. It calls multiple queries
482
 * if necessary and validates data from the database, allowing the
483
 * DatabaseAccessor to be just simple translation to SQL/other
484 485 486 487
 * 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
488
 * work as it is with whatever DatabaseAccessor.
489
 */
490 491
class DatabaseClient : public DataSourceClient {
public:
492 493 494
    /**
     * \brief Constructor
     *
495
     * It initializes the client with a database via the given accessor.
496
     *
497
     * \exception isc::InvalidParameter if accessor is NULL. It might throw
498 499
     * standard allocation exception as well, but doesn't throw anything else.
     *
500
     * \param rrclass The RR class of the zones that this client will handle.
501 502 503
     * \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.
504
     */
505
    DatabaseClient(isc::dns::RRClass rrclass,
506
                   boost::shared_ptr<DatabaseAccessor> accessor);
507

508 509 510 511 512
    /**
     * \brief Corresponding ZoneFinder implementation
     *
     * The zone finder implementation for database data sources. Similarly
     * to the DatabaseClient, it translates the queries to methods of the
513
     * database.
514 515 516 517 518 519 520 521 522 523 524 525 526 527
     *
     * 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
         *
528
         * \param database The database (shared with DatabaseClient) to
529 530
         *     be used for queries (the one asked for ID before).
         * \param zone_id The zone ID which was returned from
531
         *     DatabaseAccessor::getZone and which will be passed to further
532
         *     calls to the database.
533 534 535
         * \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.
536
         */
537 538
        Finder(boost::shared_ptr<DatabaseAccessor> database, int zone_id,
               const isc::dns::Name& origin);
Michal 'vorner' Vaner's avatar
Michal 'vorner' Vaner committed
539 540
        // The following three methods are just implementations of inherited
        // ZoneFinder's pure virtual methods.
541 542
        virtual isc::dns::Name getOrigin() const;
        virtual isc::dns::RRClass getClass() const;
543 544 545

        /**
         * \brief Find an RRset in the datasource
546
         *
Jelte Jansen's avatar
Jelte Jansen committed
547 548 549 550 551 552 553 554 555 556 557
         * 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
558
         *
559 560 561 562 563 564 565 566 567 568 569 570 571 572
         * \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
573 574 575 576 577 578 579 580
         * \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
581 582
         * \param options Options about how to search.
         *     See ZoneFinder::FindOptions.
583
         */
584 585 586
        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
587
                                const FindOptions options = FIND_DEFAULT);
Jelte Jansen's avatar
Jelte Jansen committed
588

589 590 591 592 593 594 595 596
        /**
         * \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_); }
597

598
        /**
599
         * \brief The database accessor.
600
         *
601
         * This function provides the database accessor stored inside as
602 603 604
         * passed to the constructor. This is meant for testing purposes and
         * normal applications shouldn't need it.
         */
605 606
        const DatabaseAccessor& getAccessor() const {
            return (*accessor_);
607
        }
608
    private:
609
        boost::shared_ptr<DatabaseAccessor> accessor_;
610
        const int zone_id_;
611
        const isc::dns::Name origin_;
612

613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
        /**
         * \brief Searches database for an RRset
         *
         * This method scans RRs of single domain specified by name and finds
         * RRset with given type or any of redirection RRsets that are
         * requested.
         *
         * This function is used internally by find(), because this part is
         * called multiple times with slightly different parameters.
         *
         * \param name Which domain name should be scanned.
         * \param type The RRType which is requested. This can be NULL, in
         *     which case the method will look for the redirections only.
         * \param want_cname If this is true, CNAME redirection may be returned
         *     instead of the RRset with given type. If there's CNAME and
         *     something else or the CNAME has multiple RRs, it throws
         *     DataSourceError.
         * \param want_dname If this is true, DNAME redirection may be returned
         *     instead. This is with type = NULL only and is not checked in
         *     other circumstances. If the DNAME has multiple RRs, it throws
         *     DataSourceError.
634 635
         * \param want_ns This allows redirection by NS to be returned. If
         *     any other data is met as well, DataSourceError is thrown.
636 637 638
         * \param construct_name If set to non-NULL, the resulting RRset will
         *     be constructed for this name instead of the queried one. This
         *     is useful for wildcards.
639 640 641 642
         * \note It may happen that some of the above error conditions are not
         *     detected in some circumstances. The goal here is not to validate
         *     the domain in DB, but to avoid bad behaviour resulting from
         *     broken data.
643 644 645 646 647 648 649
         * \return First part of the result tells if the domain contains any
         *     RRs. This can be used to decide between NXDOMAIN and NXRRSET.
         *     The second part is the RRset found (if any) with any relevant
         *     signatures attached to it.
         * \todo This interface doesn't look very elegant. Any better idea
         *     would be nice.
         */
650 651
        std::pair<bool, isc::dns::RRsetPtr> getRRset(const isc::dns::Name&
                                                     name,
652 653 654 655
                                                     const isc::dns::RRType*
                                                     type,
                                                     bool want_cname,
                                                     bool want_dname,
656 657 658
                                                     bool want_ns, const
                                                     isc::dns::Name*
                                                     construct_name = NULL);
659

660 661 662 663 664 665 666 667 668
        /**
         * \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);
669
    };
670

671 672 673
    /**
     * \brief Find a zone in the database
     *
674
     * This queries database's getZone to find the best matching zone.
675 676 677 678
     * 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
679 680 681 682 683
     * \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.
684
     */
685
    virtual FindResult findZone(const isc::dns::Name& name) const;
686

687 688 689 690 691 692 693 694 695 696
    /**
     * \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
697 698
     *     doesn't implement iteration. But in case it is not implemented
     *     and the zone doesn't exist, DataSourceError is thrown.
699 700 701 702 703 704
     * \exception Anything else the underlying DatabaseConnection might
     *     want to throw.
     * \param name The origin of the zone to iterate.
     * \return Shared pointer to the iterator (it will never be NULL)
     */
    virtual ZoneIteratorPtr getIterator(const isc::dns::Name& name) const;
Jelte Jansen's avatar
Jelte Jansen committed
705

706 707 708 709
    /// 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.
710 711
    virtual ZoneUpdaterPtr getUpdater(const isc::dns::Name& name,
                                      bool replace) const;
712

713
private:
714 715 716
    /// \brief The RR class that this client handles.
    const isc::dns::RRClass rrclass_;

717 718
    /// \brief The accessor to our database.
    const boost::shared_ptr<DatabaseAccessor> accessor_;
719 720 721 722 723
};

}
}

724 725 726 727 728
#endif  // __DATABASE_DATASRC_H

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