src/filter_virt_db.cpp

   1 /* $Id: filter_virt_db.cpp,v 1.40 2006-05-16 11:53:54 adam Exp $
   2    Copyright (c) 2005-2006, Index Data.
   3
   4 %LICENSE%
   5  */
   6
   7 #include "config.hpp"
   8
   9 #include "filter.hpp"
  10 #include "package.hpp"
  11
  12 #include <boost/thread/mutex.hpp>
  13 #include <boost/thread/condition.hpp>
  14 #include <boost/shared_ptr.hpp>
  15
  16 #include "util.hpp"
  17 #include "filter_virt_db.hpp"
  18
  19 #include <yaz/zgdu.h>
  20 #include <yaz/otherinfo.h>
  21 #include <yaz/diagbib1.h>
  22
  23 #include <map>
  24 #include <iostream>
  25
  26 namespace mp = metaproxy_1;
  27 namespace yf = mp::filter;
  28
  29 namespace metaproxy_1 {
  30     namespace filter {
  31
  32         struct Virt_db::Set {
  33             Set(BackendPtr b, std::string setname);
  34             Set();
  35             ~Set();
  36
  37             BackendPtr m_backend;
  38             std::string m_setname;
  39         };
  40         struct Virt_db::Map {
  41             Map(std::list<std::string> targets, std::string route);
  42             Map();
  43             std::list<std::string> m_targets;
  44             std::string m_route;
  45         };
  46         struct Virt_db::Backend {
  47             mp::Session m_backend_session;
  48             std::list<std::string> m_frontend_databases;
  49             std::list<std::string> m_targets;
  50             std::string m_route;
  51             bool m_named_result_sets;
  52             int m_number_of_sets;
  53         };
  54         struct Virt_db::Frontend {
  55             Frontend(Rep *rep);
  56             ~Frontend();
  57             mp::Session m_session;
  58             bool m_is_virtual;
  59             bool m_in_use;
  60             yazpp_1::GDU m_init_gdu;
  61             std::list<BackendPtr> m_backend_list;
  62             std::map<std::string,Virt_db::Set> m_sets;
  63
  64             void search(Package &package, Z_APDU *apdu);
  65             void present(Package &package, Z_APDU *apdu);
  66             void scan(Package &package, Z_APDU *apdu);
  67
  68             void close(Package &package);
  69             typedef std::map<std::string,Virt_db::Set>::iterator Sets_it;
  70
  71             void fixup_npr(Package &p, BackendPtr b);
  72
  73             void fixup_npr(Z_Records *records, std::string database,
  74                            ODR odr);
  75
  76             BackendPtr lookup_backend_from_databases(
  77                 std::list<std::string> databases);
  78             BackendPtr create_backend_from_databases(
  79                 std::list<std::string> databases,
  80                 int &error_code,
  81                 std::string &failing_database);
  82
  83             BackendPtr init_backend(std::list<std::string> database,
  84                                     Package &package,
  85                                     int &error_code, std::string &addinfo);
  86             Rep *m_p;
  87         };
  88         class Virt_db::Rep {
  89             friend class Virt_db;
  90             friend struct Frontend;
  91
  92             FrontendPtr get_frontend(Package &package);
  93             void release_frontend(Package &package);
  94         private:
  95             std::map<std::string, Virt_db::Map>m_maps;
  96             typedef std::map<std::string,Virt_db::Set>::iterator Sets_it;
  97             boost::mutex m_mutex;
  98             boost::condition m_cond_session_ready;
  99             std::map<mp::Session, FrontendPtr> m_clients;
 100         };
 101     }
 102 }
 103
 104 yf::Virt_db::BackendPtr yf::Virt_db::Frontend::lookup_backend_from_databases(
 105     std::list<std::string> databases)
 106 {
 107     std::list<BackendPtr>::const_iterator map_it;
 108     map_it = m_backend_list.begin();
 109     for (; map_it != m_backend_list.end(); map_it++)
 110         if ((*map_it)->m_frontend_databases == databases)
 111             return *map_it;
 112     BackendPtr null;
 113     return null;
 114 }
 115
 116 yf::Virt_db::BackendPtr yf::Virt_db::Frontend::create_backend_from_databases(
 117     std::list<std::string> databases, int &error_code, std::string &addinfo)
 118 {
 119     BackendPtr b(new Backend);
 120     std::list<std::string>::const_iterator db_it = databases.begin();
 121
 122     b->m_number_of_sets = 0;
 123     b->m_frontend_databases = databases;
 124     b->m_named_result_sets = false;
 125
 126     bool first_route = true;
 127
 128     std::map<std::string,bool> targets_dedup;
 129     for (; db_it != databases.end(); db_it++)
 130     {
 131         std::map<std::string, Virt_db::Map>::iterator map_it;
 132         map_it = m_p->m_maps.find(mp::util::database_name_normalize(*db_it));
 133         if (map_it == m_p->m_maps.end())  // database not found
 134         {
 135             error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 136             addinfo = *db_it;
 137             BackendPtr ptr;
 138             return ptr;
 139         }
 140         std::list<std::string>::const_iterator t_it =
 141             map_it->second.m_targets.begin();
 142         for (; t_it != map_it->second.m_targets.end(); t_it++)
 143             targets_dedup[*t_it] = true;
 144
 145         // see if we have a route conflict.
 146         if (!first_route && b->m_route != map_it->second.m_route)
 147         {
 148             // we have a conflict..
 149             error_code =  YAZ_BIB1_COMBI_OF_SPECIFIED_DATABASES_UNSUPP;
 150             BackendPtr ptr;
 151             return ptr;
 152         }
 153         b->m_route = map_it->second.m_route;
 154         first_route = false;
 155     }
 156     std::map<std::string,bool>::const_iterator tm_it = targets_dedup.begin();
 157     for (; tm_it != targets_dedup.end(); tm_it++)
 158         b->m_targets.push_back(tm_it->first);
 159
 160     return b;
 161 }
 162
 163 yf::Virt_db::BackendPtr yf::Virt_db::Frontend::init_backend(
 164     std::list<std::string> databases, mp::Package &package,
 165     int &error_code, std::string &addinfo)
 166 {
 167     BackendPtr b = create_backend_from_databases(databases, error_code,
 168                                                  addinfo);
 169     if (!b)
 170         return b;
 171     Package init_package(b->m_backend_session, package.origin());
 172     init_package.copy_filter(package);
 173
 174     mp::odr odr;
 175
 176     Z_APDU *init_apdu = zget_APDU(odr, Z_APDU_initRequest);
 177
 178     mp::util::set_vhost_otherinfo(&init_apdu->u.initRequest->otherInfo, odr,
 179                                    b->m_targets);
 180     Z_InitRequest *req = init_apdu->u.initRequest;
 181
 182     // copy stuff from Frontend Init Request
 183     Z_GDU *org_gdu = m_init_gdu.get();
 184     Z_InitRequest *org_init = org_gdu->u.z3950->u.initRequest;
 185
 186     req->idAuthentication = org_init->idAuthentication;
 187     req->implementationId = org_init->implementationId;
 188     req->implementationName = org_init->implementationName;
 189     req->implementationVersion = org_init->implementationVersion;
 190
 191     ODR_MASK_SET(req->options, Z_Options_search);
 192     ODR_MASK_SET(req->options, Z_Options_present);
 193     ODR_MASK_SET(req->options, Z_Options_namedResultSets);
 194     ODR_MASK_SET(req->options, Z_Options_scan);
 195
 196     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_1);
 197     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_2);
 198     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_3);
 199
 200     init_package.request() = init_apdu;
 201
 202     init_package.move(b->m_route);  // sending init
 203
 204     Z_GDU *gdu = init_package.response().get();
 205     // we hope to get an init response
 206     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 207         Z_APDU_initResponse)
 208     {
 209         Z_InitResponse *res = gdu->u.z3950->u.initResponse;
 210         if (ODR_MASK_GET(res->options, Z_Options_namedResultSets))
 211         {
 212             b->m_named_result_sets = true;
 213         }
 214         if (!*res->result)
 215         {
 216             mp::util::get_init_diagnostics(res, error_code, addinfo);
 217             BackendPtr null;
 218             return null;
 219         }
 220     }
 221     else
 222     {
 223         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 224         // addinfo = database;
 225         BackendPtr null;
 226         return null;
 227     }
 228     if (init_package.session().is_closed())
 229     {
 230         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 231         // addinfo = database;
 232         BackendPtr null;
 233         return null;
 234     }
 235
 236     m_backend_list.push_back(b);
 237     return b;
 238 }
 239
 240 void yf::Virt_db::Frontend::search(mp::Package &package, Z_APDU *apdu_req)
 241 {
 242     Z_SearchRequest *req = apdu_req->u.searchRequest;
 243     std::string vhost;
 244     std::string resultSetId = req->resultSetName;
 245     mp::odr odr;
 246
 247     std::list<std::string> databases;
 248     int i;
 249     for (i = 0; i<req->num_databaseNames; i++)
 250         databases.push_back(req->databaseNames[i]);
 251
 252     BackendPtr b; // null for now
 253     Sets_it sets_it = m_sets.find(req->resultSetName);
 254     if (sets_it != m_sets.end())
 255     {
 256         // result set already exist
 257         // if replace indicator is off: we return diagnostic if
 258         // result set already exist.
 259         if (*req->replaceIndicator == 0)
 260         {
 261             Z_APDU *apdu =
 262                 odr.create_searchResponse(
 263                     apdu_req,
 264                     YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
 265                     0);
 266             package.response() = apdu;
 267
 268             return;
 269         }
 270         sets_it->second.m_backend->m_number_of_sets--;
 271
 272         // pick up any existing backend with a database match
 273         std::list<BackendPtr>::const_iterator map_it;
 274         map_it = m_backend_list.begin();
 275         for (; map_it != m_backend_list.end(); map_it++)
 276         {
 277             BackendPtr tmp = *map_it;
 278             if (tmp->m_frontend_databases == databases)
 279                 break;
 280         }
 281         if (map_it != m_backend_list.end())
 282             b = *map_it;
 283     }
 284     else
 285     {
 286         // new result set.
 287
 288         // pick up any existing database with named result sets ..
 289         // or one which has no result sets.. yet.
 290         std::list<BackendPtr>::const_iterator map_it;
 291         map_it = m_backend_list.begin();
 292         for (; map_it != m_backend_list.end(); map_it++)
 293         {
 294             BackendPtr tmp = *map_it;
 295             if (tmp->m_frontend_databases == databases &&
 296                 (tmp->m_named_result_sets ||
 297                  tmp->m_number_of_sets == 0))
 298                 break;
 299         }
 300         if (map_it != m_backend_list.end())
 301             b = *map_it;
 302     }
 303     if (!b)  // no backend yet. Must create a new one
 304     {
 305         int error_code;
 306         std::string addinfo;
 307         b = init_backend(databases, package, error_code, addinfo);
 308         if (!b)
 309         {
 310             // did not get a backend (unavailable somehow?)
 311
 312             Z_APDU *apdu =
 313                 odr.create_searchResponse(
 314                     apdu_req, error_code, addinfo.c_str());
 315             package.response() = apdu;
 316             return;
 317         }
 318     }
 319     m_sets.erase(req->resultSetName);
 320     // sending search to backend
 321     Package search_package(b->m_backend_session, package.origin());
 322
 323     search_package.copy_filter(package);
 324
 325     std::string backend_setname;
 326     if (b->m_named_result_sets)
 327     {
 328         backend_setname = std::string(req->resultSetName);
 329     }
 330     else
 331     {
 332         backend_setname = "default";
 333         req->resultSetName = odr_strdup(odr, backend_setname.c_str());
 334     }
 335
 336     // pick first targets spec and move the databases from it ..
 337     std::list<std::string>::const_iterator t_it = b->m_targets.begin();
 338     if (t_it != b->m_targets.end())
 339     {
 340         mp::util::set_databases_from_zurl(odr, *t_it,
 341                                                 &req->num_databaseNames,
 342                                                 &req->databaseNames);
 343     }
 344
 345     *req->replaceIndicator = 1;
 346
 347     search_package.request() = yazpp_1::GDU(apdu_req);
 348
 349     search_package.move(b->m_route);
 350
 351     if (search_package.session().is_closed())
 352     {
 353         package.response() = search_package.response();
 354         package.session().close();
 355         return;
 356     }
 357     b->m_number_of_sets++;
 358
 359     m_sets[resultSetId] = Virt_db::Set(b, backend_setname);
 360     fixup_npr(search_package, b);
 361     package.response() = search_package.response();
 362 }
 363
 364 yf::Virt_db::Frontend::Frontend(Rep *rep)
 365 {
 366     m_p = rep;
 367     m_is_virtual = false;
 368 }
 369
 370 void yf::Virt_db::Frontend::close(mp::Package &package)
 371 {
 372     std::list<BackendPtr>::const_iterator b_it;
 373
 374     for (b_it = m_backend_list.begin(); b_it != m_backend_list.end(); b_it++)
 375     {
 376         (*b_it)->m_backend_session.close();
 377         Package close_package((*b_it)->m_backend_session, package.origin());
 378         close_package.copy_filter(package);
 379         close_package.move((*b_it)->m_route);
 380     }
 381     m_backend_list.clear();
 382 }
 383
 384 yf::Virt_db::Frontend::~Frontend()
 385 {
 386 }
 387
 388 yf::Virt_db::FrontendPtr yf::Virt_db::Rep::get_frontend(mp::Package &package)
 389 {
 390     boost::mutex::scoped_lock lock(m_mutex);
 391
 392     std::map<mp::Session,yf::Virt_db::FrontendPtr>::iterator it;
 393
 394     while(true)
 395     {
 396         it = m_clients.find(package.session());
 397         if (it == m_clients.end())
 398             break;
 399
 400         if (!it->second->m_in_use)
 401         {
 402             it->second->m_in_use = true;
 403             return it->second;
 404         }
 405         m_cond_session_ready.wait(lock);
 406     }
 407     FrontendPtr f(new Frontend(this));
 408     m_clients[package.session()] = f;
 409     f->m_in_use = true;
 410     return f;
 411 }
 412
 413 void yf::Virt_db::Rep::release_frontend(mp::Package &package)
 414 {
 415     boost::mutex::scoped_lock lock(m_mutex);
 416     std::map<mp::Session,yf::Virt_db::FrontendPtr>::iterator it;
 417
 418     it = m_clients.find(package.session());
 419     if (it != m_clients.end())
 420     {
 421         if (package.session().is_closed())
 422         {
 423             it->second->close(package);
 424             m_clients.erase(it);
 425         }
 426         else
 427         {
 428             it->second->m_in_use = false;
 429         }
 430         m_cond_session_ready.notify_all();
 431     }
 432 }
 433
 434 yf::Virt_db::Set::Set(BackendPtr b, std::string setname)
 435     :  m_backend(b), m_setname(setname)
 436 {
 437 }
 438
 439
 440 yf::Virt_db::Set::Set()
 441 {
 442 }
 443
 444
 445 yf::Virt_db::Set::~Set()
 446 {
 447 }
 448
 449 yf::Virt_db::Map::Map(std::list<std::string> targets, std::string route)
 450     : m_targets(targets), m_route(route)
 451 {
 452 }
 453
 454 yf::Virt_db::Map::Map()
 455 {
 456 }
 457
 458 yf::Virt_db::Virt_db() : m_p(new Virt_db::Rep)
 459 {
 460 }
 461
 462 yf::Virt_db::~Virt_db() {
 463 }
 464
 465
 466 void yf::Virt_db::Frontend::fixup_npr(Z_Records *records, std::string database,
 467                                       ODR odr)
 468 {
 469     if (records && records->which == Z_Records_DBOSD)
 470     {
 471         Z_NamePlusRecordList *nprlist = records->u.databaseOrSurDiagnostics;
 472         int i;
 473         for (i = 0; i < nprlist->num_records; i++)
 474         {
 475             Z_NamePlusRecord *npr = nprlist->records[i];
 476             npr->databaseName = odr_strdup(odr, database.c_str());
 477         }
 478     }
 479 }
 480
 481 void yf::Virt_db::Frontend::fixup_npr(mp::Package &p, BackendPtr b)
 482 {
 483     Z_GDU *gdu = p.response().get();
 484     mp::odr odr;
 485     std::string database = "dummy";
 486     std::list<std::string>::const_iterator db_it =
 487         b->m_frontend_databases.begin();
 488     if (db_it != b->m_frontend_databases.end())
 489         database = *db_it;
 490
 491     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 492         Z_APDU_presentResponse)
 493     {
 494         fixup_npr(gdu->u.z3950->u.presentResponse->records, database, odr);
 495         p.response() = gdu;
 496     }
 497     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 498         Z_APDU_searchResponse)
 499     {
 500         fixup_npr(gdu->u.z3950->u.searchResponse->records, database, odr);
 501         p.response() = gdu;
 502     }
 503 }
 504
 505 void yf::Virt_db::Frontend::present(mp::Package &package, Z_APDU *apdu_req)
 506 {
 507     Z_PresentRequest *req = apdu_req->u.presentRequest;
 508     std::string resultSetId = req->resultSetId;
 509     mp::odr odr;
 510
 511     Sets_it sets_it = m_sets.find(resultSetId);
 512     if (sets_it == m_sets.end())
 513     {
 514         Z_APDU *apdu =
 515             odr.create_presentResponse(
 516                 apdu_req,
 517                 YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
 518                 resultSetId.c_str());
 519         package.response() = apdu;
 520         return;
 521     }
 522     Session *id =
 523         new mp::Session(sets_it->second.m_backend->m_backend_session);
 524
 525     // sending present to backend
 526     Package present_package(*id, package.origin());
 527     present_package.copy_filter(package);
 528
 529     req->resultSetId = odr_strdup(odr, sets_it->second.m_setname.c_str());
 530
 531     present_package.request() = yazpp_1::GDU(apdu_req);
 532
 533     present_package.move(sets_it->second.m_backend->m_route);
 534
 535     fixup_npr(present_package, sets_it->second.m_backend);
 536
 537     if (present_package.session().is_closed())
 538     {
 539         package.response() = present_package.response();
 540         package.session().close();
 541         return;
 542     }
 543     else
 544     {
 545         package.response() = present_package.response();
 546     }
 547     delete id;
 548 }
 549
 550 void yf::Virt_db::Frontend::scan(mp::Package &package, Z_APDU *apdu_req)
 551 {
 552     Z_ScanRequest *req = apdu_req->u.scanRequest;
 553     std::string vhost;
 554     mp::odr odr;
 555
 556     std::list<std::string> databases;
 557     int i;
 558     for (i = 0; i<req->num_databaseNames; i++)
 559         databases.push_back(req->databaseNames[i]);
 560
 561     BackendPtr b;
 562     // pick up any existing backend with a database match
 563     std::list<BackendPtr>::const_iterator map_it;
 564     map_it = m_backend_list.begin();
 565     for (; map_it != m_backend_list.end(); map_it++)
 566     {
 567         BackendPtr tmp = *map_it;
 568         if (tmp->m_frontend_databases == databases)
 569             break;
 570     }
 571     if (map_it != m_backend_list.end())
 572         b = *map_it;
 573     if (!b)  // no backend yet. Must create a new one
 574     {
 575         int error_code;
 576         std::string addinfo;
 577         b = init_backend(databases, package, error_code, addinfo);
 578         if (!b)
 579         {
 580             // did not get a backend (unavailable somehow?)
 581             Z_APDU *apdu =
 582                 odr.create_scanResponse(
 583                     apdu_req, error_code, addinfo.c_str());
 584             package.response() = apdu;
 585
 586             return;
 587         }
 588     }
 589     // sending scan to backend
 590     Package scan_package(b->m_backend_session, package.origin());
 591
 592     scan_package.copy_filter(package);
 593
 594     // pick first targets spec and move the databases from it ..
 595     std::list<std::string>::const_iterator t_it = b->m_targets.begin();
 596     if (t_it != b->m_targets.end())
 597     {
 598         mp::util::set_databases_from_zurl(odr, *t_it,
 599                                                 &req->num_databaseNames,
 600                                                 &req->databaseNames);
 601     }
 602     scan_package.request() = yazpp_1::GDU(apdu_req);
 603
 604     scan_package.move(b->m_route);
 605
 606     if (scan_package.session().is_closed())
 607     {
 608         package.response() = scan_package.response();
 609         package.session().close();
 610         return;
 611     }
 612     package.response() = scan_package.response();
 613 }
 614
 615
 616 void yf::Virt_db::add_map_db2targets(std::string db,
 617                                      std::list<std::string> targets,
 618                                      std::string route)
 619 {
 620     m_p->m_maps[mp::util::database_name_normalize(db)]
 621         = Virt_db::Map(targets, route);
 622 }
 623
 624
 625 void yf::Virt_db::add_map_db2target(std::string db,
 626                                     std::string target,
 627                                     std::string route)
 628 {
 629     std::list<std::string> targets;
 630     targets.push_back(target);
 631
 632     m_p->m_maps[mp::util::database_name_normalize(db)]
 633         = Virt_db::Map(targets, route);
 634 }
 635
 636 void yf::Virt_db::process(mp::Package &package) const
 637 {
 638     FrontendPtr f = m_p->get_frontend(package);
 639
 640     Z_GDU *gdu = package.request().get();
 641
 642     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 643         Z_APDU_initRequest && !f->m_is_virtual)
 644     {
 645         Z_InitRequest *req = gdu->u.z3950->u.initRequest;
 646
 647         std::list<std::string> vhosts;
 648         mp::util::get_vhost_otherinfo(&req->otherInfo, false, vhosts);
 649         if (vhosts.size() == 0)
 650         {
 651             f->m_init_gdu = gdu;
 652
 653             mp::odr odr;
 654             Z_APDU *apdu = odr.create_initResponse(gdu->u.z3950, 0, 0);
 655             Z_InitResponse *resp = apdu->u.initResponse;
 656
 657             int i;
 658             static const int masks[] = {
 659                 Z_Options_search,
 660                 Z_Options_present,
 661                 Z_Options_namedResultSets,
 662                 Z_Options_scan,
 663                 -1
 664             };
 665             for (i = 0; masks[i] != -1; i++)
 666                 if (ODR_MASK_GET(req->options, masks[i]))
 667                     ODR_MASK_SET(resp->options, masks[i]);
 668
 669             static const int versions[] = {
 670                 Z_ProtocolVersion_1,
 671                 Z_ProtocolVersion_2,
 672                 Z_ProtocolVersion_3,
 673                 -1
 674             };
 675             for (i = 0; versions[i] != -1; i++)
 676                 if (ODR_MASK_GET(req->protocolVersion, versions[i]))
 677                     ODR_MASK_SET(resp->protocolVersion, versions[i]);
 678                 else
 679                     break;
 680
 681             package.response() = apdu;
 682             f->m_is_virtual = true;
 683         }
 684         else
 685             package.move();
 686     }
 687     else if (!f->m_is_virtual)
 688         package.move();
 689     else if (gdu && gdu->which == Z_GDU_Z3950)
 690     {
 691         Z_APDU *apdu = gdu->u.z3950;
 692         if (apdu->which == Z_APDU_initRequest)
 693         {
 694             mp::odr odr;
 695
 696             package.response() = odr.create_close(
 697                 apdu,
 698                 Z_Close_protocolError,
 699                 "double init");
 700
 701             package.session().close();
 702         }
 703         else if (apdu->which == Z_APDU_searchRequest)
 704         {
 705             f->search(package, apdu);
 706         }
 707         else if (apdu->which == Z_APDU_presentRequest)
 708         {
 709             f->present(package, apdu);
 710         }
 711         else if (apdu->which == Z_APDU_scanRequest)
 712         {
 713             f->scan(package, apdu);
 714         }
 715         else
 716         {
 717             mp::odr odr;
 718
 719             package.response() = odr.create_close(
 720                 apdu, Z_Close_protocolError,
 721                 "unsupported APDU in filter_virt_db");
 722
 723             package.session().close();
 724         }
 725     }
 726     m_p->release_frontend(package);
 727 }
 728
 729
 730 void mp::filter::Virt_db::configure(const xmlNode * ptr)
 731 {
 732     for (ptr = ptr->children; ptr; ptr = ptr->next)
 733     {
 734         if (ptr->type != XML_ELEMENT_NODE)
 735             continue;
 736         if (!strcmp((const char *) ptr->name, "virtual"))
 737         {
 738             std::string database;
 739             std::list<std::string> targets;
 740             xmlNode *v_node = ptr->children;
 741             for (; v_node; v_node = v_node->next)
 742             {
 743                 if (v_node->type != XML_ELEMENT_NODE)
 744                     continue;
 745
 746                 if (mp::xml::is_element_yp2(v_node, "database"))
 747                     database = mp::xml::get_text(v_node);
 748                 else if (mp::xml::is_element_yp2(v_node, "target"))
 749                     targets.push_back(mp::xml::get_text(v_node));
 750                 else
 751                     throw mp::filter::FilterException
 752                         ("Bad element "
 753                          + std::string((const char *) v_node->name)
 754                          + " in virtual section"
 755                             );
 756             }
 757             std::string route = mp::xml::get_route(ptr);
 758             add_map_db2targets(database, targets, route);
 759         }
 760         else
 761         {
 762             throw mp::filter::FilterException
 763                 ("Bad element "
 764                  + std::string((const char *) ptr->name)
 765                  + " in virt_db filter");
 766         }
 767     }
 768 }
 769
 770 static mp::filter::Base* filter_creator()
 771 {
 772     return new mp::filter::Virt_db;
 773 }
 774
 775 extern "C" {
 776     struct metaproxy_1_filter_struct metaproxy_1_filter_virt_db = {
 777         0,
 778         "virt_db",
 779         filter_creator
 780     };
 781 }
 782
 783
 784 /*
 785  * Local variables:
 786  * c-basic-offset: 4
 787  * indent-tabs-mode: nil
 788  * c-file-style: "stroustrup"
 789  * End:
 790  * vim: shiftwidth=4 tabstop=8 expandtab
 791  */