src/filter_virt_db.cpp

   1 /* $Id: filter_virt_db.cpp,v 1.51 2007-05-09 21:23:09 adam Exp $
   2    Copyright (c) 2005-2007, Index Data.
   3
   4 This file is part of Metaproxy.
   5
   6 Metaproxy is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 Metaproxy is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with Metaproxy; see the file LICENSE.  If not, write to the
  18 Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.
  20  */
  21 /* $Id: filter_virt_db.cpp,v 1.51 2007-05-09 21:23:09 adam Exp $
  22    Copyright (c) 2005-2007, Index Data.
  23
  24    See the LICENSE file for details
  25  */
  26
  27 #include "config.hpp"
  28
  29 #include "filter.hpp"
  30 #include "package.hpp"
  31
  32 #include <boost/thread/mutex.hpp>
  33 #include <boost/thread/condition.hpp>
  34 #include <boost/shared_ptr.hpp>
  35
  36 #include "util.hpp"
  37 #include "filter_virt_db.hpp"
  38
  39 #include <yaz/zgdu.h>
  40 #include <yaz/otherinfo.h>
  41 #include <yaz/diagbib1.h>
  42
  43 #include <map>
  44 #include <iostream>
  45
  46 namespace mp = metaproxy_1;
  47 namespace yf = mp::filter;
  48
  49 namespace metaproxy_1 {
  50     namespace filter {
  51
  52         struct VirtualDB::Set {
  53             Set(BackendPtr b, std::string setname);
  54             Set();
  55             ~Set();
  56
  57             BackendPtr m_backend;
  58             std::string m_setname;
  59         };
  60         struct VirtualDB::Map {
  61             Map(std::list<std::string> targets, std::string route);
  62             Map();
  63             std::list<std::string> m_targets;
  64             std::string m_route;
  65         };
  66         struct VirtualDB::Backend {
  67             mp::Session m_backend_session;
  68             std::list<std::string> m_frontend_databases;
  69             std::list<std::string> m_targets;
  70             std::string m_route;
  71             bool m_named_result_sets;
  72             int m_number_of_sets;
  73         };
  74         struct VirtualDB::Frontend {
  75             Frontend(Rep *rep);
  76             ~Frontend();
  77             mp::Session m_session;
  78             bool m_is_virtual;
  79             bool m_in_use;
  80             yazpp_1::GDU m_init_gdu;
  81             std::list<BackendPtr> m_backend_list;
  82             std::map<std::string,VirtualDB::Set> m_sets;
  83
  84             void search(Package &package, Z_APDU *apdu);
  85             void present(Package &package, Z_APDU *apdu);
  86             void scan(Package &package, Z_APDU *apdu);
  87
  88             void close(Package &package);
  89             typedef std::map<std::string,VirtualDB::Set>::iterator Sets_it;
  90
  91             void fixup_package(Package &p, BackendPtr b);
  92             void fixup_npr_record(ODR odr, Z_NamePlusRecord *npr,
  93                                   BackendPtr b);
  94             void fixup_npr_records(ODR odr, Z_Records *records,
  95                                    BackendPtr b);
  96
  97             BackendPtr lookup_backend_from_databases(
  98                 std::list<std::string> databases);
  99             BackendPtr create_backend_from_databases(
 100                 std::list<std::string> databases,
 101                 int &error_code,
 102                 std::string &failing_database);
 103
 104             BackendPtr init_backend(std::list<std::string> database,
 105                                     Package &package,
 106                                     int &error_code, std::string &addinfo);
 107             Rep *m_p;
 108         };
 109         class VirtualDB::Rep {
 110             friend class VirtualDB;
 111             friend struct Frontend;
 112
 113             FrontendPtr get_frontend(Package &package);
 114             void release_frontend(Package &package);
 115         private:
 116             std::map<std::string, VirtualDB::Map>m_maps;
 117             typedef std::map<std::string,VirtualDB::Set>::iterator Sets_it;
 118             boost::mutex m_mutex;
 119             boost::condition m_cond_session_ready;
 120             std::map<mp::Session, FrontendPtr> m_clients;
 121         };
 122     }
 123 }
 124
 125 yf::VirtualDB::BackendPtr yf::VirtualDB::Frontend::lookup_backend_from_databases(
 126     std::list<std::string> databases)
 127 {
 128     std::list<BackendPtr>::const_iterator map_it;
 129     map_it = m_backend_list.begin();
 130     for (; map_it != m_backend_list.end(); map_it++)
 131         if ((*map_it)->m_frontend_databases == databases)
 132             return *map_it;
 133     BackendPtr null;
 134     return null;
 135 }
 136
 137 yf::VirtualDB::BackendPtr yf::VirtualDB::Frontend::create_backend_from_databases(
 138     std::list<std::string> databases, int &error_code, std::string &addinfo)
 139 {
 140     BackendPtr b(new Backend);
 141     std::list<std::string>::const_iterator db_it = databases.begin();
 142
 143     b->m_number_of_sets = 0;
 144     b->m_frontend_databases = databases;
 145     b->m_named_result_sets = false;
 146
 147     bool first_route = true;
 148
 149     std::map<std::string,bool> targets_dedup;
 150     for (; db_it != databases.end(); db_it++)
 151     {
 152         std::map<std::string, VirtualDB::Map>::iterator map_it;
 153         map_it = m_p->m_maps.find(mp::util::database_name_normalize(*db_it));
 154         if (map_it == m_p->m_maps.end())  // database not found
 155         {
 156             error_code = YAZ_BIB1_DATABASE_DOES_NOT_EXIST;
 157             addinfo = *db_it;
 158             BackendPtr ptr;
 159             return ptr;
 160         }
 161         std::list<std::string>::const_iterator t_it =
 162             map_it->second.m_targets.begin();
 163         for (; t_it != map_it->second.m_targets.end(); t_it++)
 164             targets_dedup[*t_it] = true;
 165
 166         // see if we have a route conflict.
 167         if (!first_route && b->m_route != map_it->second.m_route)
 168         {
 169             // we have a conflict..
 170             error_code =  YAZ_BIB1_COMBI_OF_SPECIFIED_DATABASES_UNSUPP;
 171             BackendPtr ptr;
 172             return ptr;
 173         }
 174         b->m_route = map_it->second.m_route;
 175         first_route = false;
 176     }
 177     std::map<std::string,bool>::const_iterator tm_it = targets_dedup.begin();
 178     for (; tm_it != targets_dedup.end(); tm_it++)
 179         b->m_targets.push_back(tm_it->first);
 180
 181     return b;
 182 }
 183
 184 yf::VirtualDB::BackendPtr yf::VirtualDB::Frontend::init_backend(
 185     std::list<std::string> databases, mp::Package &package,
 186     int &error_code, std::string &addinfo)
 187 {
 188     BackendPtr b = create_backend_from_databases(databases, error_code,
 189                                                  addinfo);
 190     if (!b)
 191         return b;
 192     Package init_package(b->m_backend_session, package.origin());
 193     init_package.copy_filter(package);
 194
 195     mp::odr odr;
 196
 197     Z_APDU *init_apdu = zget_APDU(odr, Z_APDU_initRequest);
 198
 199     mp::util::set_vhost_otherinfo(&init_apdu->u.initRequest->otherInfo, odr,
 200                                    b->m_targets);
 201     Z_InitRequest *req = init_apdu->u.initRequest;
 202
 203     // copy stuff from Frontend Init Request
 204     Z_GDU *org_gdu = m_init_gdu.get();
 205     Z_InitRequest *org_init = org_gdu->u.z3950->u.initRequest;
 206
 207     req->idAuthentication = org_init->idAuthentication;
 208     req->implementationId = org_init->implementationId;
 209     req->implementationName = org_init->implementationName;
 210     req->implementationVersion = org_init->implementationVersion;
 211
 212     ODR_MASK_SET(req->options, Z_Options_search);
 213     ODR_MASK_SET(req->options, Z_Options_present);
 214     ODR_MASK_SET(req->options, Z_Options_namedResultSets);
 215     ODR_MASK_SET(req->options, Z_Options_scan);
 216
 217     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_1);
 218     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_2);
 219     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_3);
 220
 221     init_package.request() = init_apdu;
 222
 223     init_package.move(b->m_route);  // sending init
 224
 225     Z_GDU *gdu = init_package.response().get();
 226     // we hope to get an init response
 227     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 228         Z_APDU_initResponse)
 229     {
 230         Z_InitResponse *res = gdu->u.z3950->u.initResponse;
 231         if (ODR_MASK_GET(res->options, Z_Options_namedResultSets))
 232         {
 233             b->m_named_result_sets = true;
 234         }
 235         if (!*res->result)
 236         {
 237             error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 238             mp::util::get_init_diagnostics(res, error_code, addinfo);
 239             BackendPtr null;
 240             return null;
 241         }
 242     }
 243     else
 244     {
 245         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 246         // addinfo = database;
 247         BackendPtr null;
 248         return null;
 249     }
 250     if (init_package.session().is_closed())
 251     {
 252         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 253         // addinfo = database;
 254         BackendPtr null;
 255         return null;
 256     }
 257
 258     m_backend_list.push_back(b);
 259     return b;
 260 }
 261
 262 void yf::VirtualDB::Frontend::search(mp::Package &package, Z_APDU *apdu_req)
 263 {
 264     Z_SearchRequest *req = apdu_req->u.searchRequest;
 265     std::string vhost;
 266     std::string resultSetId = req->resultSetName;
 267     mp::odr odr;
 268
 269     std::list<std::string> databases;
 270     int i;
 271     for (i = 0; i<req->num_databaseNames; i++)
 272         databases.push_back(req->databaseNames[i]);
 273
 274     BackendPtr b; // null for now
 275     Sets_it sets_it = m_sets.find(req->resultSetName);
 276     if (sets_it != m_sets.end())
 277     {
 278         // result set already exist
 279         // if replace indicator is off: we return diagnostic if
 280         // result set already exist.
 281         if (*req->replaceIndicator == 0)
 282         {
 283             Z_APDU *apdu =
 284                 odr.create_searchResponse(
 285                     apdu_req,
 286                     YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
 287                     0);
 288             package.response() = apdu;
 289
 290             return;
 291         }
 292         sets_it->second.m_backend->m_number_of_sets--;
 293
 294         // pick up any existing backend with a database match
 295         std::list<BackendPtr>::const_iterator map_it;
 296         map_it = m_backend_list.begin();
 297         for (; map_it != m_backend_list.end(); map_it++)
 298         {
 299             BackendPtr tmp = *map_it;
 300             if (tmp->m_frontend_databases == databases)
 301                 break;
 302         }
 303         if (map_it != m_backend_list.end())
 304             b = *map_it;
 305     }
 306     else
 307     {
 308         // new result set.
 309
 310         // pick up any existing database with named result sets ..
 311         // or one which has no result sets.. yet.
 312         std::list<BackendPtr>::const_iterator map_it;
 313         map_it = m_backend_list.begin();
 314         for (; map_it != m_backend_list.end(); map_it++)
 315         {
 316             BackendPtr tmp = *map_it;
 317             if (tmp->m_frontend_databases == databases &&
 318                 (tmp->m_named_result_sets ||
 319                  tmp->m_number_of_sets == 0))
 320                 break;
 321         }
 322         if (map_it != m_backend_list.end())
 323             b = *map_it;
 324     }
 325     if (!b)  // no backend yet. Must create a new one
 326     {
 327         int error_code;
 328         std::string addinfo;
 329         b = init_backend(databases, package, error_code, addinfo);
 330         if (!b)
 331         {
 332             // did not get a backend (unavailable somehow?)
 333
 334             Z_APDU *apdu =
 335                 odr.create_searchResponse(
 336                     apdu_req, error_code, addinfo.c_str());
 337             package.response() = apdu;
 338             return;
 339         }
 340     }
 341     m_sets.erase(req->resultSetName);
 342     // sending search to backend
 343     Package search_package(b->m_backend_session, package.origin());
 344
 345     search_package.copy_filter(package);
 346
 347     std::string backend_setname;
 348     if (b->m_named_result_sets)
 349     {
 350         backend_setname = std::string(req->resultSetName);
 351     }
 352     else
 353     {
 354         backend_setname = "default";
 355         req->resultSetName = odr_strdup(odr, backend_setname.c_str());
 356     }
 357
 358     // pick first targets spec and move the databases from it ..
 359     std::list<std::string>::const_iterator t_it = b->m_targets.begin();
 360     if (t_it != b->m_targets.end())
 361     {
 362         mp::util::set_databases_from_zurl(odr, *t_it,
 363                                                 &req->num_databaseNames,
 364                                                 &req->databaseNames);
 365     }
 366
 367     *req->replaceIndicator = 1;
 368
 369     search_package.request() = yazpp_1::GDU(apdu_req);
 370
 371     search_package.move(b->m_route);
 372
 373     if (search_package.session().is_closed())
 374     {
 375         package.response() = search_package.response();
 376         package.session().close();
 377         return;
 378     }
 379     b->m_number_of_sets++;
 380
 381     m_sets[resultSetId] = VirtualDB::Set(b, backend_setname);
 382     fixup_package(search_package, b);
 383     package.response() = search_package.response();
 384 }
 385
 386 yf::VirtualDB::Frontend::Frontend(Rep *rep)
 387 {
 388     m_p = rep;
 389     m_is_virtual = false;
 390 }
 391
 392 void yf::VirtualDB::Frontend::close(mp::Package &package)
 393 {
 394     std::list<BackendPtr>::const_iterator b_it;
 395
 396     for (b_it = m_backend_list.begin(); b_it != m_backend_list.end(); b_it++)
 397     {
 398         (*b_it)->m_backend_session.close();
 399         Package close_package((*b_it)->m_backend_session, package.origin());
 400         close_package.copy_filter(package);
 401         close_package.move((*b_it)->m_route);
 402     }
 403     m_backend_list.clear();
 404 }
 405
 406 yf::VirtualDB::Frontend::~Frontend()
 407 {
 408 }
 409
 410 yf::VirtualDB::FrontendPtr yf::VirtualDB::Rep::get_frontend(mp::Package &package)
 411 {
 412     boost::mutex::scoped_lock lock(m_mutex);
 413
 414     std::map<mp::Session,yf::VirtualDB::FrontendPtr>::iterator it;
 415
 416     while(true)
 417     {
 418         it = m_clients.find(package.session());
 419         if (it == m_clients.end())
 420             break;
 421
 422         if (!it->second->m_in_use)
 423         {
 424             it->second->m_in_use = true;
 425             return it->second;
 426         }
 427         m_cond_session_ready.wait(lock);
 428     }
 429     FrontendPtr f(new Frontend(this));
 430     m_clients[package.session()] = f;
 431     f->m_in_use = true;
 432     return f;
 433 }
 434
 435 void yf::VirtualDB::Rep::release_frontend(mp::Package &package)
 436 {
 437     boost::mutex::scoped_lock lock(m_mutex);
 438     std::map<mp::Session,yf::VirtualDB::FrontendPtr>::iterator it;
 439
 440     it = m_clients.find(package.session());
 441     if (it != m_clients.end())
 442     {
 443         if (package.session().is_closed())
 444         {
 445             it->second->close(package);
 446             m_clients.erase(it);
 447         }
 448         else
 449         {
 450             it->second->m_in_use = false;
 451         }
 452         m_cond_session_ready.notify_all();
 453     }
 454 }
 455
 456 yf::VirtualDB::Set::Set(BackendPtr b, std::string setname)
 457     :  m_backend(b), m_setname(setname)
 458 {
 459 }
 460
 461
 462 yf::VirtualDB::Set::Set()
 463 {
 464 }
 465
 466
 467 yf::VirtualDB::Set::~Set()
 468 {
 469 }
 470
 471 yf::VirtualDB::Map::Map(std::list<std::string> targets, std::string route)
 472     : m_targets(targets), m_route(route)
 473 {
 474 }
 475
 476 yf::VirtualDB::Map::Map()
 477 {
 478 }
 479
 480 yf::VirtualDB::VirtualDB() : m_p(new VirtualDB::Rep)
 481 {
 482 }
 483
 484 yf::VirtualDB::~VirtualDB() {
 485 }
 486
 487 void yf::VirtualDB::Frontend::fixup_npr_record(ODR odr, Z_NamePlusRecord *npr,
 488                                              BackendPtr b)
 489 {
 490     if (npr->databaseName)
 491     {
 492         std::string b_database = std::string(npr->databaseName);
 493
 494         // consider each of the frontend databases..
 495         std::list<std::string>::const_iterator db_it;
 496         for (db_it = b->m_frontend_databases.begin();
 497              db_it != b->m_frontend_databases.end(); db_it++)
 498         {
 499             // see which target it corresponds to.. (if any)
 500             std::map<std::string,VirtualDB::Map>::const_iterator map_it;
 501             map_it = m_p->m_maps.find(*db_it);
 502             if (map_it != m_p->m_maps.end())
 503             {
 504                 VirtualDB::Map m = map_it->second;
 505
 506                 std::list<std::string>::const_iterator t;
 507                 for (t = m.m_targets.begin(); t != m.m_targets.end(); t++)
 508                 {
 509                     if (*t == b_database)
 510                     {
 511                         npr->databaseName = odr_strdup(odr, (*db_it).c_str());
 512                         return;
 513                     }
 514                 }
 515             }
 516
 517         }
 518         db_it = b->m_frontend_databases.begin();
 519         if (db_it != b->m_frontend_databases.end())
 520         {
 521             std::string database = *db_it;
 522             npr->databaseName = odr_strdup(odr, database.c_str());
 523         }
 524     }
 525 }
 526
 527 void yf::VirtualDB::Frontend::fixup_npr_records(ODR odr, Z_Records *records,
 528                                               BackendPtr b)
 529 {
 530     if (records && records->which == Z_Records_DBOSD)
 531     {
 532         Z_NamePlusRecordList *nprlist = records->u.databaseOrSurDiagnostics;
 533         int i;
 534         for (i = 0; i < nprlist->num_records; i++)
 535         {
 536             fixup_npr_record(odr, nprlist->records[i], b);
 537         }
 538     }
 539 }
 540
 541 void yf::VirtualDB::Frontend::fixup_package(mp::Package &p, BackendPtr b)
 542 {
 543     Z_GDU *gdu = p.response().get();
 544     mp::odr odr;
 545
 546     if (gdu && gdu->which == Z_GDU_Z3950)
 547     {
 548         Z_APDU *apdu = gdu->u.z3950;
 549         if (apdu->which == Z_APDU_presentResponse)
 550         {
 551             fixup_npr_records(odr, apdu->u.presentResponse->records, b);
 552             p.response() = gdu;
 553         }
 554         else if (apdu->which == Z_APDU_searchResponse)
 555         {
 556             fixup_npr_records(odr,  apdu->u.searchResponse->records, b);
 557             p.response() = gdu;
 558         }
 559     }
 560 }
 561
 562 void yf::VirtualDB::Frontend::present(mp::Package &package, Z_APDU *apdu_req)
 563 {
 564     Z_PresentRequest *req = apdu_req->u.presentRequest;
 565     std::string resultSetId = req->resultSetId;
 566     mp::odr odr;
 567
 568     Sets_it sets_it = m_sets.find(resultSetId);
 569     if (sets_it == m_sets.end())
 570     {
 571         Z_APDU *apdu =
 572             odr.create_presentResponse(
 573                 apdu_req,
 574                 YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
 575                 resultSetId.c_str());
 576         package.response() = apdu;
 577         return;
 578     }
 579     Session *id =
 580         new mp::Session(sets_it->second.m_backend->m_backend_session);
 581
 582     // sending present to backend
 583     Package present_package(*id, package.origin());
 584     present_package.copy_filter(package);
 585
 586     req->resultSetId = odr_strdup(odr, sets_it->second.m_setname.c_str());
 587
 588     present_package.request() = yazpp_1::GDU(apdu_req);
 589
 590     present_package.move(sets_it->second.m_backend->m_route);
 591
 592     fixup_package(present_package, sets_it->second.m_backend);
 593
 594     if (present_package.session().is_closed())
 595     {
 596         package.response() = present_package.response();
 597         package.session().close();
 598         return;
 599     }
 600     else
 601     {
 602         package.response() = present_package.response();
 603     }
 604     delete id;
 605 }
 606
 607 void yf::VirtualDB::Frontend::scan(mp::Package &package, Z_APDU *apdu_req)
 608 {
 609     Z_ScanRequest *req = apdu_req->u.scanRequest;
 610     std::string vhost;
 611     mp::odr odr;
 612
 613     std::list<std::string> databases;
 614     int i;
 615     for (i = 0; i<req->num_databaseNames; i++)
 616         databases.push_back(req->databaseNames[i]);
 617
 618     BackendPtr b;
 619     // pick up any existing backend with a database match
 620     std::list<BackendPtr>::const_iterator map_it;
 621     map_it = m_backend_list.begin();
 622     for (; map_it != m_backend_list.end(); map_it++)
 623     {
 624         BackendPtr tmp = *map_it;
 625         if (tmp->m_frontend_databases == databases)
 626             break;
 627     }
 628     if (map_it != m_backend_list.end())
 629         b = *map_it;
 630     if (!b)  // no backend yet. Must create a new one
 631     {
 632         int error_code;
 633         std::string addinfo;
 634         b = init_backend(databases, package, error_code, addinfo);
 635         if (!b)
 636         {
 637             // did not get a backend (unavailable somehow?)
 638             Z_APDU *apdu =
 639                 odr.create_scanResponse(
 640                     apdu_req, error_code, addinfo.c_str());
 641             package.response() = apdu;
 642
 643             return;
 644         }
 645     }
 646     // sending scan to backend
 647     Package scan_package(b->m_backend_session, package.origin());
 648
 649     scan_package.copy_filter(package);
 650
 651     // pick first targets spec and move the databases from it ..
 652     std::list<std::string>::const_iterator t_it = b->m_targets.begin();
 653     if (t_it != b->m_targets.end())
 654     {
 655         mp::util::set_databases_from_zurl(odr, *t_it,
 656                                                 &req->num_databaseNames,
 657                                                 &req->databaseNames);
 658     }
 659     scan_package.request() = yazpp_1::GDU(apdu_req);
 660
 661     scan_package.move(b->m_route);
 662
 663     if (scan_package.session().is_closed())
 664     {
 665         package.response() = scan_package.response();
 666         package.session().close();
 667         return;
 668     }
 669     package.response() = scan_package.response();
 670 }
 671
 672
 673 void yf::VirtualDB::add_map_db2targets(std::string db,
 674                                      std::list<std::string> targets,
 675                                      std::string route)
 676 {
 677     m_p->m_maps[mp::util::database_name_normalize(db)]
 678         = VirtualDB::Map(targets, route);
 679 }
 680
 681
 682 void yf::VirtualDB::add_map_db2target(std::string db,
 683                                     std::string target,
 684                                     std::string route)
 685 {
 686     std::list<std::string> targets;
 687     targets.push_back(target);
 688
 689     m_p->m_maps[mp::util::database_name_normalize(db)]
 690         = VirtualDB::Map(targets, route);
 691 }
 692
 693 void yf::VirtualDB::process(mp::Package &package) const
 694 {
 695     FrontendPtr f = m_p->get_frontend(package);
 696
 697     Z_GDU *gdu = package.request().get();
 698
 699     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 700         Z_APDU_initRequest && !f->m_is_virtual)
 701     {
 702         Z_InitRequest *req = gdu->u.z3950->u.initRequest;
 703
 704         std::list<std::string> vhosts;
 705         mp::util::get_vhost_otherinfo(req->otherInfo, vhosts);
 706         if (vhosts.size() == 0)
 707         {
 708             f->m_init_gdu = gdu;
 709
 710             mp::odr odr;
 711             Z_APDU *apdu = odr.create_initResponse(gdu->u.z3950, 0, 0);
 712             Z_InitResponse *resp = apdu->u.initResponse;
 713
 714             int i;
 715             static const int masks[] = {
 716                 Z_Options_search,
 717                 Z_Options_present,
 718                 Z_Options_namedResultSets,
 719                 Z_Options_scan,
 720                 -1
 721             };
 722             for (i = 0; masks[i] != -1; i++)
 723                 if (ODR_MASK_GET(req->options, masks[i]))
 724                     ODR_MASK_SET(resp->options, masks[i]);
 725
 726             static const int versions[] = {
 727                 Z_ProtocolVersion_1,
 728                 Z_ProtocolVersion_2,
 729                 Z_ProtocolVersion_3,
 730                 -1
 731             };
 732             for (i = 0; versions[i] != -1; i++)
 733                 if (ODR_MASK_GET(req->protocolVersion, versions[i]))
 734                     ODR_MASK_SET(resp->protocolVersion, versions[i]);
 735                 else
 736                     break;
 737
 738             package.response() = apdu;
 739             f->m_is_virtual = true;
 740         }
 741         else
 742             package.move();
 743     }
 744     else if (!f->m_is_virtual)
 745         package.move();
 746     else if (gdu && gdu->which == Z_GDU_Z3950)
 747     {
 748         Z_APDU *apdu = gdu->u.z3950;
 749         if (apdu->which == Z_APDU_initRequest)
 750         {
 751             mp::odr odr;
 752
 753             package.response() = odr.create_close(
 754                 apdu,
 755                 Z_Close_protocolError,
 756                 "double init");
 757
 758             package.session().close();
 759         }
 760         else if (apdu->which == Z_APDU_searchRequest)
 761         {
 762             f->search(package, apdu);
 763         }
 764         else if (apdu->which == Z_APDU_presentRequest)
 765         {
 766             f->present(package, apdu);
 767         }
 768         else if (apdu->which == Z_APDU_scanRequest)
 769         {
 770             f->scan(package, apdu);
 771         }
 772         else if (apdu->which == Z_APDU_close)
 773         {
 774             package.session().close();
 775         }
 776         else
 777         {
 778             mp::odr odr;
 779
 780             package.response() = odr.create_close(
 781                 apdu, Z_Close_protocolError,
 782                 "unsupported APDU in filter_virt_db");
 783
 784             package.session().close();
 785         }
 786     }
 787     m_p->release_frontend(package);
 788 }
 789
 790
 791 void mp::filter::VirtualDB::configure(const xmlNode * ptr)
 792 {
 793     for (ptr = ptr->children; ptr; ptr = ptr->next)
 794     {
 795         if (ptr->type != XML_ELEMENT_NODE)
 796             continue;
 797         if (!strcmp((const char *) ptr->name, "virtual"))
 798         {
 799             std::string database;
 800             std::list<std::string> targets;
 801             xmlNode *v_node = ptr->children;
 802             for (; v_node; v_node = v_node->next)
 803             {
 804                 if (v_node->type != XML_ELEMENT_NODE)
 805                     continue;
 806
 807                 if (mp::xml::is_element_mp(v_node, "database"))
 808                     database = mp::xml::get_text(v_node);
 809                 else if (mp::xml::is_element_mp(v_node, "target"))
 810                     targets.push_back(mp::xml::get_text(v_node));
 811                 else
 812                     throw mp::filter::FilterException
 813                         ("Bad element "
 814                          + std::string((const char *) v_node->name)
 815                          + " in virtual section"
 816                             );
 817             }
 818             std::string route = mp::xml::get_route(ptr);
 819             add_map_db2targets(database, targets, route);
 820         }
 821         else
 822         {
 823             throw mp::filter::FilterException
 824                 ("Bad element "
 825                  + std::string((const char *) ptr->name)
 826                  + " in virt_db filter");
 827         }
 828     }
 829 }
 830
 831 static mp::filter::Base* filter_creator()
 832 {
 833     return new mp::filter::VirtualDB;
 834 }
 835
 836 extern "C" {
 837     struct metaproxy_1_filter_struct metaproxy_1_filter_virt_db = {
 838         0,
 839         "virt_db",
 840         filter_creator
 841     };
 842 }
 843
 844
 845 /*
 846  * Local variables:
 847  * c-basic-offset: 4
 848  * indent-tabs-mode: nil
 849  * c-file-style: "stroustrup"
 850  * End:
 851  * vim: shiftwidth=4 tabstop=8 expandtab
 852  */