maintenance/backupTextPass.inc

   1 <?php
   2 /**
   3  * BackupDumper that postprocesses XML dumps from dumpBackup.php to add page text
   4  *
   5  * Copyright (C) 2005 Brion Vibber <brion@pobox.com>
   6  * https://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  * @ingroup Maintenance
  25  */
  26
  27 require_once __DIR__ . '/backup.inc';
  28
  29 /**
  30  * @ingroup Maintenance
  31  */
  32 class TextPassDumper extends BackupDumper {
  33         public $prefetch = null;
  34
  35         // when we spend more than maxTimeAllowed seconds on this run, we continue
  36         // processing until we write out the next complete page, then save output file(s),
  37         // rename it/them and open new one(s)
  38         public $maxTimeAllowed = 0; // 0 = no limit
  39
  40         protected $input = "php://stdin";
  41         protected $history = WikiExporter::FULL;
  42         protected $fetchCount = 0;
  43         protected $prefetchCount = 0;
  44         protected $prefetchCountLast = 0;
  45         protected $fetchCountLast = 0;
  46
  47         protected $maxFailures = 5;
  48         protected $maxConsecutiveFailedTextRetrievals = 200;
  49         protected $failureTimeout = 5; // Seconds to sleep after db failure
  50
  51         protected $php = "php";
  52         protected $spawn = false;
  53
  54         /**
  55          * @var bool|resource
  56          */
  57         protected $spawnProc = false;
  58
  59         /**
  60          * @var bool|resource
  61          */
  62         protected $spawnWrite = false;
  63
  64         /**
  65          * @var bool|resource
  66          */
  67         protected $spawnRead = false;
  68
  69         /**
  70          * @var bool|resource
  71          */
  72         protected $spawnErr = false;
  73
  74         protected $xmlwriterobj = false;
  75
  76         protected $timeExceeded = false;
  77         protected $firstPageWritten = false;
  78         protected $lastPageWritten = false;
  79         protected $checkpointJustWritten = false;
  80         protected $checkpointFiles = array();
  81
  82         /**
  83          * @var DatabaseBase
  84          */
  85         protected $db;
  86
  87         /**
  88          * Drop the database connection $this->db and try to get a new one.
  89          *
  90          * This function tries to get a /different/ connection if this is
  91          * possible. Hence, (if this is possible) it switches to a different
  92          * failover upon each call.
  93          *
  94          * This function resets $this->lb and closes all connections on it.
  95          *
  96          * @throws MWException
  97          */
  98         function rotateDb() {
  99                 // Cleaning up old connections
 100                 if ( isset( $this->lb ) ) {
 101                         $this->lb->closeAll();
 102                         unset( $this->lb );
 103                 }
 104
 105                 if ( $this->forcedDb !== null ) {
 106                         $this->db = $this->forcedDb;
 107
 108                         return;
 109                 }
 110
 111                 if ( isset( $this->db ) && $this->db->isOpen() ) {
 112                         throw new MWException( 'DB is set and has not been closed by the Load Balancer' );
 113                 }
 114
 115                 unset( $this->db );
 116
 117                 // Trying to set up new connection.
 118                 // We do /not/ retry upon failure, but delegate to encapsulating logic, to avoid
 119                 // individually retrying at different layers of code.
 120
 121                 // 1. The LoadBalancer.
 122                 try {
 123                         $this->lb = wfGetLBFactory()->newMainLB();
 124                 } catch ( Exception $e ) {
 125                         throw new MWException( __METHOD__
 126                                 . " rotating DB failed to obtain new load balancer (" . $e->getMessage() . ")" );
 127                 }
 128
 129                 // 2. The Connection, through the load balancer.
 130                 try {
 131                         $this->db = $this->lb->getConnection( DB_SLAVE, 'dump' );
 132                 } catch ( Exception $e ) {
 133                         throw new MWException( __METHOD__
 134                                 . " rotating DB failed to obtain new database (" . $e->getMessage() . ")" );
 135                 }
 136         }
 137
 138         function initProgress( $history = WikiExporter::FULL ) {
 139                 parent::initProgress();
 140                 $this->timeOfCheckpoint = $this->startTime;
 141         }
 142
 143         function dump( $history, $text = WikiExporter::TEXT ) {
 144                 // Notice messages will foul up your XML output even if they're
 145                 // relatively harmless.
 146                 if ( ini_get( 'display_errors' ) ) {
 147                         ini_set( 'display_errors', 'stderr' );
 148                 }
 149
 150                 $this->initProgress( $this->history );
 151
 152                 // We are trying to get an initial database connection to avoid that the
 153                 // first try of this request's first call to getText fails. However, if
 154                 // obtaining a good DB connection fails it's not a serious issue, as
 155                 // getText does retry upon failure and can start without having a working
 156                 // DB connection.
 157                 try {
 158                         $this->rotateDb();
 159                 } catch ( Exception $e ) {
 160                         // We do not even count this as failure. Just let eventual
 161                         // watchdogs know.
 162                         $this->progress( "Getting initial DB connection failed (" .
 163                                 $e->getMessage() . ")" );
 164                 }
 165
 166                 $this->egress = new ExportProgressFilter( $this->sink, $this );
 167
 168                 // it would be nice to do it in the constructor, oh well. need egress set
 169                 $this->finalOptionCheck();
 170
 171                 // we only want this so we know how to close a stream :-P
 172                 $this->xmlwriterobj = new XmlDumpWriter();
 173
 174                 $input = fopen( $this->input, "rt" );
 175                 $this->readDump( $input );
 176
 177                 if ( $this->spawnProc ) {
 178                         $this->closeSpawn();
 179                 }
 180
 181                 $this->report( true );
 182         }
 183
 184         function processOption( $opt, $val, $param ) {
 185                 global $IP;
 186                 $url = $this->processFileOpt( $val, $param );
 187
 188                 switch ( $opt ) {
 189                         case 'prefetch':
 190                                 require_once "$IP/maintenance/backupPrefetch.inc";
 191                                 $this->prefetch = new BaseDump( $url );
 192                                 break;
 193                         case 'stub':
 194                                 $this->input = $url;
 195                                 break;
 196                         case 'maxtime':
 197                                 $this->maxTimeAllowed = intval( $val ) * 60;
 198                                 break;
 199                         case 'checkpointfile':
 200                                 $this->checkpointFiles[] = $val;
 201                                 break;
 202                         case 'current':
 203                                 $this->history = WikiExporter::CURRENT;
 204                                 break;
 205                         case 'full':
 206                                 $this->history = WikiExporter::FULL;
 207                                 break;
 208                         case 'spawn':
 209                                 $this->spawn = true;
 210                                 if ( $val ) {
 211                                         $this->php = $val;
 212                                 }
 213                                 break;
 214                 }
 215         }
 216
 217         function processFileOpt( $val, $param ) {
 218                 $fileURIs = explode( ';', $param );
 219                 foreach ( $fileURIs as $URI ) {
 220                         switch ( $val ) {
 221                                 case "file":
 222                                         $newURI = $URI;
 223                                         break;
 224                                 case "gzip":
 225                                         $newURI = "compress.zlib://$URI";
 226                                         break;
 227                                 case "bzip2":
 228                                         $newURI = "compress.bzip2://$URI";
 229                                         break;
 230                                 case "7zip":
 231                                         $newURI = "mediawiki.compress.7z://$URI";
 232                                         break;
 233                                 default:
 234                                         $newURI = $URI;
 235                         }
 236                         $newFileURIs[] = $newURI;
 237                 }
 238                 $val = implode( ';', $newFileURIs );
 239
 240                 return $val;
 241         }
 242
 243         /**
 244          * Overridden to include prefetch ratio if enabled.
 245          */
 246         function showReport() {
 247                 if ( !$this->prefetch ) {
 248                         parent::showReport();
 249
 250                         return;
 251                 }
 252
 253                 if ( $this->reporting ) {
 254                         $now = wfTimestamp( TS_DB );
 255                         $nowts = microtime( true );
 256                         $deltaAll = $nowts - $this->startTime;
 257                         $deltaPart = $nowts - $this->lastTime;
 258                         $this->pageCountPart = $this->pageCount - $this->pageCountLast;
 259                         $this->revCountPart = $this->revCount - $this->revCountLast;
 260
 261                         if ( $deltaAll ) {
 262                                 $portion = $this->revCount / $this->maxCount;
 263                                 $eta = $this->startTime + $deltaAll / $portion;
 264                                 $etats = wfTimestamp( TS_DB, intval( $eta ) );
 265                                 if ( $this->fetchCount ) {
 266                                         $fetchRate = 100.0 * $this->prefetchCount / $this->fetchCount;
 267                                 } else {
 268                                         $fetchRate = '-';
 269                                 }
 270                                 $pageRate = $this->pageCount / $deltaAll;
 271                                 $revRate = $this->revCount / $deltaAll;
 272                         } else {
 273                                 $pageRate = '-';
 274                                 $revRate = '-';
 275                                 $etats = '-';
 276                                 $fetchRate = '-';
 277                         }
 278                         if ( $deltaPart ) {
 279                                 if ( $this->fetchCountLast ) {
 280                                         $fetchRatePart = 100.0 * $this->prefetchCountLast / $this->fetchCountLast;
 281                                 } else {
 282                                         $fetchRatePart = '-';
 283                                 }
 284                                 $pageRatePart = $this->pageCountPart / $deltaPart;
 285                                 $revRatePart = $this->revCountPart / $deltaPart;
 286                         } else {
 287                                 $fetchRatePart = '-';
 288                                 $pageRatePart = '-';
 289                                 $revRatePart = '-';
 290                         }
 291                         $this->progress( sprintf(
 292                                 "%s: %s (ID %d) %d pages (%0.1f|%0.1f/sec all|curr), "
 293                                         . "%d revs (%0.1f|%0.1f/sec all|curr), %0.1f%%|%0.1f%% "
 294                                         . "prefetched (all|curr), ETA %s [max %d]",
 295                                 $now, wfWikiID(), $this->ID, $this->pageCount, $pageRate,
 296                                 $pageRatePart, $this->revCount, $revRate, $revRatePart,
 297                                 $fetchRate, $fetchRatePart, $etats, $this->maxCount
 298                         ) );
 299                         $this->lastTime = $nowts;
 300                         $this->revCountLast = $this->revCount;
 301                         $this->prefetchCountLast = $this->prefetchCount;
 302                         $this->fetchCountLast = $this->fetchCount;
 303                 }
 304         }
 305
 306         function setTimeExceeded() {
 307                 $this->timeExceeded = true;
 308         }
 309
 310         function checkIfTimeExceeded() {
 311                 if ( $this->maxTimeAllowed
 312                         && ( $this->lastTime - $this->timeOfCheckpoint > $this->maxTimeAllowed )
 313                 ) {
 314                         return true;
 315                 }
 316
 317                 return false;
 318         }
 319
 320         function finalOptionCheck() {
 321                 if ( ( $this->checkpointFiles && !$this->maxTimeAllowed )
 322                         || ( $this->maxTimeAllowed && !$this->checkpointFiles )
 323                 ) {
 324                         throw new MWException( "Options checkpointfile and maxtime must be specified together.\n" );
 325                 }
 326                 foreach ( $this->checkpointFiles as $checkpointFile ) {
 327                         $count = substr_count( $checkpointFile, "%s" );
 328                         if ( $count != 2 ) {
 329                                 throw new MWException( "Option checkpointfile must contain two '%s' "
 330                                         . "for substitution of first and last pageids, count is $count instead, "
 331                                         . "file is $checkpointFile.\n" );
 332                         }
 333                 }
 334
 335                 if ( $this->checkpointFiles ) {
 336                         $filenameList = (array)$this->egress->getFilenames();
 337                         if ( count( $filenameList ) != count( $this->checkpointFiles ) ) {
 338                                 throw new MWException( "One checkpointfile must be specified "
 339                                         . "for each output option, if maxtime is used.\n" );
 340                         }
 341                 }
 342         }
 343
 344         /**
 345          * @throws MWException Failure to parse XML input
 346          * @param string $input
 347          * @return bool
 348          */
 349         function readDump( $input ) {
 350                 $this->buffer = "";
 351                 $this->openElement = false;
 352                 $this->atStart = true;
 353                 $this->state = "";
 354                 $this->lastName = "";
 355                 $this->thisPage = 0;
 356                 $this->thisRev = 0;
 357                 $this->thisRevModel = null;
 358                 $this->thisRevFormat = null;
 359
 360                 $parser = xml_parser_create( "UTF-8" );
 361                 xml_parser_set_option( $parser, XML_OPTION_CASE_FOLDING, false );
 362
 363                 xml_set_element_handler(
 364                         $parser,
 365                         array( &$this, 'startElement' ),
 366                         array( &$this, 'endElement' )
 367                 );
 368                 xml_set_character_data_handler( $parser, array( &$this, 'characterData' ) );
 369
 370                 $offset = 0; // for context extraction on error reporting
 371                 $bufferSize = 512 * 1024;
 372                 do {
 373                         if ( $this->checkIfTimeExceeded() ) {
 374                                 $this->setTimeExceeded();
 375                         }
 376                         $chunk = fread( $input, $bufferSize );
 377                         if ( !xml_parse( $parser, $chunk, feof( $input ) ) ) {
 378                                 wfDebug( "TextDumpPass::readDump encountered XML parsing error\n" );
 379
 380                                 $byte = xml_get_current_byte_index( $parser );
 381                                 $msg = wfMessage( 'xml-error-string',
 382                                         'XML import parse failure',
 383                                         xml_get_current_line_number( $parser ),
 384                                         xml_get_current_column_number( $parser ),
 385                                         $byte . ( is_null( $chunk ) ? null : ( '; "' . substr( $chunk, $byte - $offset, 16 ) . '"' ) ),
 386                                         xml_error_string( xml_get_error_code( $parser ) ) )->escaped();
 387
 388                                 xml_parser_free( $parser );
 389
 390                                 throw new MWException( $msg );
 391                         }
 392                         $offset += strlen( $chunk );
 393                 } while ( $chunk !== false && !feof( $input ) );
 394                 if ( $this->maxTimeAllowed ) {
 395                         $filenameList = (array)$this->egress->getFilenames();
 396                         // we wrote some stuff after last checkpoint that needs renamed
 397                         if ( file_exists( $filenameList[0] ) ) {
 398                                 $newFilenames = array();
 399                                 # we might have just written the header and footer and had no
 400                                 # pages or revisions written... perhaps they were all deleted
 401                                 # there's no pageID 0 so we use that. the caller is responsible
 402                                 # for deciding what to do with a file containing only the
 403                                 # siteinfo information and the mw tags.
 404                                 if ( !$this->firstPageWritten ) {
 405                                         $firstPageID = str_pad( 0, 9, "0", STR_PAD_LEFT );
 406                                         $lastPageID = str_pad( 0, 9, "0", STR_PAD_LEFT );
 407                                 } else {
 408                                         $firstPageID = str_pad( $this->firstPageWritten, 9, "0", STR_PAD_LEFT );
 409                                         $lastPageID = str_pad( $this->lastPageWritten, 9, "0", STR_PAD_LEFT );
 410                                 }
 411
 412                                 $filenameCount = count( $filenameList );
 413                                 for ( $i = 0; $i < $filenameCount; $i++ ) {
 414                                         $checkpointNameFilledIn = sprintf( $this->checkpointFiles[$i], $firstPageID, $lastPageID );
 415                                         $fileinfo = pathinfo( $filenameList[$i] );
 416                                         $newFilenames[] = $fileinfo['dirname'] . '/' . $checkpointNameFilledIn;
 417                                 }
 418                                 $this->egress->closeAndRename( $newFilenames );
 419                         }
 420                 }
 421                 xml_parser_free( $parser );
 422
 423                 return true;
 424         }
 425
 426         /**
 427          * Applies applicable export transformations to $text.
 428          *
 429          * @param string $text
 430          * @param string $model
 431          * @param string|null $format
 432          *
 433          * @return string
 434          */
 435         private function exportTransform( $text, $model, $format = null ) {
 436                 try {
 437                         $handler = ContentHandler::getForModelID( $model );
 438                         $text = $handler->exportTransform( $text, $format );
 439                 }
 440                 catch ( MWException $ex ) {
 441                         $this->progress(
 442                                 "Unable to apply export transformation for content model '$model': " .
 443                                 $ex->getMessage()
 444                         );
 445                 }
 446
 447                 return $text;
 448         }
 449
 450         /**
 451          * Tries to get the revision text for a revision id.
 452          * Export transformations are applied if the content model can is given or can be
 453          * determined from the database.
 454          *
 455          * Upon errors, retries (Up to $this->maxFailures tries each call).
 456          * If still no good revision get could be found even after this retrying, "" is returned.
 457          * If no good revision text could be returned for
 458          * $this->maxConsecutiveFailedTextRetrievals consecutive calls to getText, MWException
 459          * is thrown.
 460          *
 461          * @param string $id The revision id to get the text for
 462          * @param string|bool|null $model The content model used to determine applicable export transformations.
 463          *      If $model is null, it will be determined from the database.
 464          * @param string|null $format The content format used when applying export transformations.
 465          *
 466          * @throws MWException
 467          * @return string The revision text for $id, or ""
 468          */
 469         function getText( $id, $model = null, $format = null ) {
 470                 global $wgContentHandlerUseDB;
 471
 472                 $prefetchNotTried = true; // Whether or not we already tried to get the text via prefetch.
 473                 $text = false; // The candidate for a good text. false if no proper value.
 474                 $failures = 0; // The number of times, this invocation of getText already failed.
 475
 476                 // The number of times getText failed without yielding a good text in between.
 477                 static $consecutiveFailedTextRetrievals = 0;
 478
 479                 $this->fetchCount++;
 480
 481                 // To allow to simply return on success and do not have to worry about book keeping,
 482                 // we assume, this fetch works (possible after some retries). Nevertheless, we koop
 483                 // the old value, so we can restore it, if problems occur (See after the while loop).
 484                 $oldConsecutiveFailedTextRetrievals = $consecutiveFailedTextRetrievals;
 485                 $consecutiveFailedTextRetrievals = 0;
 486
 487                 if ( $model === null && $wgContentHandlerUseDB ) {
 488                         $row = $this->db->selectRow(
 489                                 'revision',
 490                                 array( 'rev_content_model', 'rev_content_format' ),
 491                                 array( 'rev_id' => $this->thisRev ),
 492                                 __METHOD__
 493                         );
 494
 495                         if ( $row ) {
 496                                 $model = $row->rev_content_model;
 497                                 $format = $row->rev_content_format;
 498                         }
 499                 }
 500
 501                 if ( $model === null || $model === '' ) {
 502                         $model = false;
 503                 }
 504
 505                 while ( $failures < $this->maxFailures ) {
 506
 507                         // As soon as we found a good text for the $id, we will return immediately.
 508                         // Hence, if we make it past the try catch block, we know that we did not
 509                         // find a good text.
 510
 511                         try {
 512                                 // Step 1: Get some text (or reuse from previous iteratuon if checking
 513                                 //         for plausibility failed)
 514
 515                                 // Trying to get prefetch, if it has not been tried before
 516                                 if ( $text === false && isset( $this->prefetch ) && $prefetchNotTried ) {
 517                                         $prefetchNotTried = false;
 518                                         $tryIsPrefetch = true;
 519                                         $text = $this->prefetch->prefetch( intval( $this->thisPage ),
 520                                                 intval( $this->thisRev ) );
 521
 522                                         if ( $text === null ) {
 523                                                 $text = false;
 524                                         }
 525
 526                                         if ( is_string( $text ) && $model !== false ) {
 527                                                 // Apply export transformation to text coming from an old dump.
 528                                                 // The purpose of this transformation is to convert up from legacy
 529                                                 // formats, which may still be used in the older dump that is used
 530                                                 // for pre-fetching. Applying the transformation again should not
 531                                                 // interfere with content that is already in the correct form.
 532                                                 $text = $this->exportTransform( $text, $model, $format );
 533                                         }
 534                                 }
 535
 536                                 if ( $text === false ) {
 537                                         // Fallback to asking the database
 538                                         $tryIsPrefetch = false;
 539                                         if ( $this->spawn ) {
 540                                                 $text = $this->getTextSpawned( $id );
 541                                         } else {
 542                                                 $text = $this->getTextDb( $id );
 543                                         }
 544
 545                                         if ( $text !== false && $model !== false ) {
 546                                                 // Apply export transformation to text coming from the database.
 547                                                 // Prefetched text should already have transformations applied.
 548                                                 $text = $this->exportTransform( $text, $model, $format );
 549                                         }
 550
 551                                         // No more checks for texts from DB for now.
 552                                         // If we received something that is not false,
 553                                         // We treat it as good text, regardless of whether it actually is or is not
 554                                         if ( $text !== false ) {
 555                                                 return $text;
 556                                         }
 557                                 }
 558
 559                                 if ( $text === false ) {
 560                                         throw new MWException( "Generic error while obtaining text for id " . $id );
 561                                 }
 562
 563                                 // We received a good candidate for the text of $id via some method
 564
 565                                 // Step 2: Checking for plausibility and return the text if it is
 566                                 //         plausible
 567                                 $revID = intval( $this->thisRev );
 568                                 if ( !isset( $this->db ) ) {
 569                                         throw new MWException( "No database available" );
 570                                 }
 571
 572                                 if ( $model !== CONTENT_MODEL_WIKITEXT ) {
 573                                         $revLength = strlen( $text );
 574                                 } else {
 575                                         $revLength = $this->db->selectField( 'revision', 'rev_len', array( 'rev_id' => $revID ) );
 576                                 }
 577
 578                                 if ( strlen( $text ) == $revLength ) {
 579                                         if ( $tryIsPrefetch ) {
 580                                                 $this->prefetchCount++;
 581                                         }
 582
 583                                         return $text;
 584                                 }
 585
 586                                 $text = false;
 587                                 throw new MWException( "Received text is unplausible for id " . $id );
 588                         } catch ( Exception $e ) {
 589                                 $msg = "getting/checking text " . $id . " failed (" . $e->getMessage() . ")";
 590                                 if ( $failures + 1 < $this->maxFailures ) {
 591                                         $msg .= " (Will retry " . ( $this->maxFailures - $failures - 1 ) . " more times)";
 592                                 }
 593                                 $this->progress( $msg );
 594                         }
 595
 596                         // Something went wrong; we did not a text that was plausible :(
 597                         $failures++;
 598
 599                         // A failure in a prefetch hit does not warrant resetting db connection etc.
 600                         if ( !$tryIsPrefetch ) {
 601                                 // After backing off for some time, we try to reboot the whole process as
 602                                 // much as possible to not carry over failures from one part to the other
 603                                 // parts
 604                                 sleep( $this->failureTimeout );
 605                                 try {
 606                                         $this->rotateDb();
 607                                         if ( $this->spawn ) {
 608                                                 $this->closeSpawn();
 609                                                 $this->openSpawn();
 610                                         }
 611                                 } catch ( Exception $e ) {
 612                                         $this->progress( "Rebooting getText infrastructure failed (" . $e->getMessage() . ")" .
 613                                                 " Trying to continue anyways" );
 614                                 }
 615                         }
 616                 }
 617
 618                 // Retirieving a good text for $id failed (at least) maxFailures times.
 619                 // We abort for this $id.
 620
 621                 // Restoring the consecutive failures, and maybe aborting, if the dump
 622                 // is too broken.
 623                 $consecutiveFailedTextRetrievals = $oldConsecutiveFailedTextRetrievals + 1;
 624                 if ( $consecutiveFailedTextRetrievals > $this->maxConsecutiveFailedTextRetrievals ) {
 625                         throw new MWException( "Graceful storage failure" );
 626                 }
 627
 628                 return "";
 629         }
 630
 631         /**
 632          * May throw a database error if, say, the server dies during query.
 633          * @param int $id
 634          * @return bool|string
 635          * @throws MWException
 636          */
 637         private function getTextDb( $id ) {
 638                 global $wgContLang;
 639                 if ( !isset( $this->db ) ) {
 640                         throw new MWException( __METHOD__ . "No database available" );
 641                 }
 642                 $row = $this->db->selectRow( 'text',
 643                         array( 'old_text', 'old_flags' ),
 644                         array( 'old_id' => $id ),
 645                         __METHOD__ );
 646                 $text = Revision::getRevisionText( $row );
 647                 if ( $text === false ) {
 648                         return false;
 649                 }
 650                 $stripped = str_replace( "\r", "", $text );
 651                 $normalized = $wgContLang->normalize( $stripped );
 652
 653                 return $normalized;
 654         }
 655
 656         private function getTextSpawned( $id ) {
 657                 wfSuppressWarnings();
 658                 if ( !$this->spawnProc ) {
 659                         // First time?
 660                         $this->openSpawn();
 661                 }
 662                 $text = $this->getTextSpawnedOnce( $id );
 663                 wfRestoreWarnings();
 664
 665                 return $text;
 666         }
 667
 668         function openSpawn() {
 669                 global $IP;
 670
 671                 if ( file_exists( "$IP/../multiversion/MWScript.php" ) ) {
 672                         $cmd = implode( " ",
 673                                 array_map( 'wfEscapeShellArg',
 674                                         array(
 675                                                 $this->php,
 676                                                 "$IP/../multiversion/MWScript.php",
 677                                                 "fetchText.php",
 678                                                 '--wiki', wfWikiID() ) ) );
 679                 } else {
 680                         $cmd = implode( " ",
 681                                 array_map( 'wfEscapeShellArg',
 682                                         array(
 683                                                 $this->php,
 684                                                 "$IP/maintenance/fetchText.php",
 685                                                 '--wiki', wfWikiID() ) ) );
 686                 }
 687                 $spec = array(
 688                         0 => array( "pipe", "r" ),
 689                         1 => array( "pipe", "w" ),
 690                         2 => array( "file", "/dev/null", "a" ) );
 691                 $pipes = array();
 692
 693                 $this->progress( "Spawning database subprocess: $cmd" );
 694                 $this->spawnProc = proc_open( $cmd, $spec, $pipes );
 695                 if ( !$this->spawnProc ) {
 696                         // shit
 697                         $this->progress( "Subprocess spawn failed." );
 698
 699                         return false;
 700                 }
 701                 list(
 702                         $this->spawnWrite, // -> stdin
 703                         $this->spawnRead, // <- stdout
 704                 ) = $pipes;
 705
 706                 return true;
 707         }
 708
 709         private function closeSpawn() {
 710                 wfSuppressWarnings();
 711                 if ( $this->spawnRead ) {
 712                         fclose( $this->spawnRead );
 713                 }
 714                 $this->spawnRead = false;
 715                 if ( $this->spawnWrite ) {
 716                         fclose( $this->spawnWrite );
 717                 }
 718                 $this->spawnWrite = false;
 719                 if ( $this->spawnErr ) {
 720                         fclose( $this->spawnErr );
 721                 }
 722                 $this->spawnErr = false;
 723                 if ( $this->spawnProc ) {
 724                         pclose( $this->spawnProc );
 725                 }
 726                 $this->spawnProc = false;
 727                 wfRestoreWarnings();
 728         }
 729
 730         private function getTextSpawnedOnce( $id ) {
 731                 global $wgContLang;
 732
 733                 $ok = fwrite( $this->spawnWrite, "$id\n" );
 734                 // $this->progress( ">> $id" );
 735                 if ( !$ok ) {
 736                         return false;
 737                 }
 738
 739                 $ok = fflush( $this->spawnWrite );
 740                 // $this->progress( ">> [flush]" );
 741                 if ( !$ok ) {
 742                         return false;
 743                 }
 744
 745                 // check that the text id they are sending is the one we asked for
 746                 // this avoids out of sync revision text errors we have encountered in the past
 747                 $newId = fgets( $this->spawnRead );
 748                 if ( $newId === false ) {
 749                         return false;
 750                 }
 751                 if ( $id != intval( $newId ) ) {
 752                         return false;
 753                 }
 754
 755                 $len = fgets( $this->spawnRead );
 756                 // $this->progress( "<< " . trim( $len ) );
 757                 if ( $len === false ) {
 758                         return false;
 759                 }
 760
 761                 $nbytes = intval( $len );
 762                 // actual error, not zero-length text
 763                 if ( $nbytes < 0 ) {
 764                         return false;
 765                 }
 766
 767                 $text = "";
 768
 769                 // Subprocess may not send everything at once, we have to loop.
 770                 while ( $nbytes > strlen( $text ) ) {
 771                         $buffer = fread( $this->spawnRead, $nbytes - strlen( $text ) );
 772                         if ( $buffer === false ) {
 773                                 break;
 774                         }
 775                         $text .= $buffer;
 776                 }
 777
 778                 $gotbytes = strlen( $text );
 779                 if ( $gotbytes != $nbytes ) {
 780                         $this->progress( "Expected $nbytes bytes from database subprocess, got $gotbytes " );
 781
 782                         return false;
 783                 }
 784
 785                 // Do normalization in the dump thread...
 786                 $stripped = str_replace( "\r", "", $text );
 787                 $normalized = $wgContLang->normalize( $stripped );
 788
 789                 return $normalized;
 790         }
 791
 792         function startElement( $parser, $name, $attribs ) {
 793                 $this->checkpointJustWritten = false;
 794
 795                 $this->clearOpenElement( null );
 796                 $this->lastName = $name;
 797
 798                 if ( $name == 'revision' ) {
 799                         $this->state = $name;
 800                         $this->egress->writeOpenPage( null, $this->buffer );
 801                         $this->buffer = "";
 802                 } elseif ( $name == 'page' ) {
 803                         $this->state = $name;
 804                         if ( $this->atStart ) {
 805                                 $this->egress->writeOpenStream( $this->buffer );
 806                                 $this->buffer = "";
 807                                 $this->atStart = false;
 808                         }
 809                 }
 810
 811                 if ( $name == "text" && isset( $attribs['id'] ) ) {
 812                         $id = $attribs['id'];
 813                         $model = trim( $this->thisRevModel );
 814                         $format = trim( $this->thisRevFormat );
 815
 816                         $model = $model === '' ? null : $model;
 817                         $format = $format === '' ? null : $format;
 818
 819                         $text = $this->getText( $id, $model, $format );
 820                         $this->openElement = array( $name, array( 'xml:space' => 'preserve' ) );
 821                         if ( strlen( $text ) > 0 ) {
 822                                 $this->characterData( $parser, $text );
 823                         }
 824                 } else {
 825                         $this->openElement = array( $name, $attribs );
 826                 }
 827         }
 828
 829         function endElement( $parser, $name ) {
 830                 $this->checkpointJustWritten = false;
 831
 832                 if ( $this->openElement ) {
 833                         $this->clearOpenElement( "" );
 834                 } else {
 835                         $this->buffer .= "</$name>";
 836                 }
 837
 838                 if ( $name == 'revision' ) {
 839                         $this->egress->writeRevision( null, $this->buffer );
 840                         $this->buffer = "";
 841                         $this->thisRev = "";
 842                         $this->thisRevModel = null;
 843                         $this->thisRevFormat = null;
 844                 } elseif ( $name == 'page' ) {
 845                         if ( !$this->firstPageWritten ) {
 846                                 $this->firstPageWritten = trim( $this->thisPage );
 847                         }
 848                         $this->lastPageWritten = trim( $this->thisPage );
 849                         if ( $this->timeExceeded ) {
 850                                 $this->egress->writeClosePage( $this->buffer );
 851                                 // nasty hack, we can't just write the chardata after the
 852                                 // page tag, it will include leading blanks from the next line
 853                                 $this->egress->sink->write( "\n" );
 854
 855                                 $this->buffer = $this->xmlwriterobj->closeStream();
 856                                 $this->egress->writeCloseStream( $this->buffer );
 857
 858                                 $this->buffer = "";
 859                                 $this->thisPage = "";
 860                                 // this could be more than one file if we had more than one output arg
 861
 862                                 $filenameList = (array)$this->egress->getFilenames();
 863                                 $newFilenames = array();
 864                                 $firstPageID = str_pad( $this->firstPageWritten, 9, "0", STR_PAD_LEFT );
 865                                 $lastPageID = str_pad( $this->lastPageWritten, 9, "0", STR_PAD_LEFT );
 866                                 $filenamesCount = count( $filenameList );
 867                                 for ( $i = 0; $i < $filenamesCount; $i++ ) {
 868                                         $checkpointNameFilledIn = sprintf( $this->checkpointFiles[$i], $firstPageID, $lastPageID );
 869                                         $fileinfo = pathinfo( $filenameList[$i] );
 870                                         $newFilenames[] = $fileinfo['dirname'] . '/' . $checkpointNameFilledIn;
 871                                 }
 872                                 $this->egress->closeRenameAndReopen( $newFilenames );
 873                                 $this->buffer = $this->xmlwriterobj->openStream();
 874                                 $this->timeExceeded = false;
 875                                 $this->timeOfCheckpoint = $this->lastTime;
 876                                 $this->firstPageWritten = false;
 877                                 $this->checkpointJustWritten = true;
 878                         } else {
 879                                 $this->egress->writeClosePage( $this->buffer );
 880                                 $this->buffer = "";
 881                                 $this->thisPage = "";
 882                         }
 883                 } elseif ( $name == 'mediawiki' ) {
 884                         $this->egress->writeCloseStream( $this->buffer );
 885                         $this->buffer = "";
 886                 }
 887         }
 888
 889         function characterData( $parser, $data ) {
 890                 $this->clearOpenElement( null );
 891                 if ( $this->lastName == "id" ) {
 892                         if ( $this->state == "revision" ) {
 893                                 $this->thisRev .= $data;
 894                         } elseif ( $this->state == "page" ) {
 895                                 $this->thisPage .= $data;
 896                         }
 897                 }
 898                 elseif ( $this->lastName == "model" ) {
 899                         $this->thisRevModel .= $data;
 900                 }
 901                 elseif ( $this->lastName == "format" ) {
 902                         $this->thisRevFormat .= $data;
 903                 }
 904
 905                 // have to skip the newline left over from closepagetag line of
 906                 // end of checkpoint files. nasty hack!!
 907                 if ( $this->checkpointJustWritten ) {
 908                         if ( $data[0] == "\n" ) {
 909                                 $data = substr( $data, 1 );
 910                         }
 911                         $this->checkpointJustWritten = false;
 912                 }
 913                 $this->buffer .= htmlspecialchars( $data );
 914         }
 915
 916         function clearOpenElement( $style ) {
 917                 if ( $this->openElement ) {
 918                         $this->buffer .= Xml::element( $this->openElement[0], $this->openElement[1], $style );
 919                         $this->openElement = false;
 920                 }
 921         }
 922 }