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