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 $bufferSize = 524288; // In bytes. Maximum size to read from the stub in on go.
  52
  53         protected $php = "php";
  54         protected $spawn = false;
  55
  56         /**
  57          * @var bool|resource
  58          */
  59         protected $spawnProc = false;
  60
  61         /**
  62          * @var bool|resource
  63          */
  64         protected $spawnWrite = false;
  65
  66         /**
  67          * @var bool|resource
  68          */
  69         protected $spawnRead = false;
  70
  71         /**
  72          * @var bool|resource
  73          */
  74         protected $spawnErr = false;
  75
  76         protected $xmlwriterobj = false;
  77
  78         protected $timeExceeded = false;
  79         protected $firstPageWritten = false;
  80         protected $lastPageWritten = false;
  81         protected $checkpointJustWritten = false;
  82         protected $checkpointFiles = array();
  83
  84         /**
  85          * @var DatabaseBase
  86          */
  87         protected $db;
  88
  89         /**
  90          * Drop the database connection $this->db and try to get a new one.
  91          *
  92          * This function tries to get a /different/ connection if this is
  93          * possible. Hence, (if this is possible) it switches to a different
  94          * failover upon each call.
  95          *
  96          * This function resets $this->lb and closes all connections on it.
  97          *
  98          * @throws MWException
  99          */
 100         function rotateDb() {
 101                 // Cleaning up old connections
 102                 if ( isset( $this->lb ) ) {
 103                         $this->lb->closeAll();
 104                         unset( $this->lb );
 105                 }
 106
 107                 if ( $this->forcedDb !== null ) {
 108                         $this->db = $this->forcedDb;
 109
 110                         return;
 111                 }
 112
 113                 if ( isset( $this->db ) && $this->db->isOpen() ) {
 114                         throw new MWException( 'DB is set and has not been closed by the Load Balancer' );
 115                 }
 116
 117                 unset( $this->db );
 118
 119                 // Trying to set up new connection.
 120                 // We do /not/ retry upon failure, but delegate to encapsulating logic, to avoid
 121                 // individually retrying at different layers of code.
 122
 123                 // 1. The LoadBalancer.
 124                 try {
 125                         $this->lb = wfGetLBFactory()->newMainLB();
 126                 } catch ( Exception $e ) {
 127                         throw new MWException( __METHOD__
 128                                 . " rotating DB failed to obtain new load balancer (" . $e->getMessage() . ")" );
 129                 }
 130
 131                 // 2. The Connection, through the load balancer.
 132                 try {
 133                         $this->db = $this->lb->getConnection( DB_SLAVE, 'dump' );
 134                 } catch ( Exception $e ) {
 135                         throw new MWException( __METHOD__
 136                                 . " rotating DB failed to obtain new database (" . $e->getMessage() . ")" );
 137                 }
 138         }
 139
 140         function initProgress( $history = WikiExporter::FULL ) {
 141                 parent::initProgress();
 142                 $this->timeOfCheckpoint = $this->startTime;
 143         }
 144
 145         function dump( $history, $text = WikiExporter::TEXT ) {
 146                 // Notice messages will foul up your XML output even if they're
 147                 // relatively harmless.
 148                 if ( ini_get( 'display_errors' ) ) {
 149                         ini_set( 'display_errors', 'stderr' );
 150                 }
 151
 152                 $this->initProgress( $this->history );
 153
 154                 // We are trying to get an initial database connection to avoid that the
 155                 // first try of this request's first call to getText fails. However, if
 156                 // obtaining a good DB connection fails it's not a serious issue, as
 157                 // getText does retry upon failure and can start without having a working
 158                 // DB connection.
 159                 try {
 160                         $this->rotateDb();
 161                 } catch ( Exception $e ) {
 162                         // We do not even count this as failure. Just let eventual
 163                         // watchdogs know.
 164                         $this->progress( "Getting initial DB connection failed (" .
 165                                 $e->getMessage() . ")" );
 166                 }
 167
 168                 $this->egress = new ExportProgressFilter( $this->sink, $this );
 169
 170                 // it would be nice to do it in the constructor, oh well. need egress set
 171                 $this->finalOptionCheck();
 172
 173                 // we only want this so we know how to close a stream :-P
 174                 $this->xmlwriterobj = new XmlDumpWriter();
 175
 176                 $input = fopen( $this->input, "rt" );
 177                 $this->readDump( $input );
 178
 179                 if ( $this->spawnProc ) {
 180                         $this->closeSpawn();
 181                 }
 182
 183                 $this->report( true );
 184         }
 185
 186         function processOption( $opt, $val, $param ) {
 187                 global $IP;
 188                 $url = $this->processFileOpt( $val, $param );
 189
 190                 switch ( $opt ) {
 191                         case 'buffersize':
 192                                 // Lower bound for xml reading buffer size is 4 KB
 193                                 $this->bufferSize = max( intval( $val ), 4 * 1024 );
 194                                 break;
 195                         case 'prefetch':
 196                                 require_once "$IP/maintenance/backupPrefetch.inc";
 197                                 $this->prefetch = new BaseDump( $url );
 198                                 break;
 199                         case 'stub':
 200                                 $this->input = $url;
 201                                 break;
 202                         case 'maxtime':
 203                                 $this->maxTimeAllowed = intval( $val ) * 60;
 204                                 break;
 205                         case 'checkpointfile':
 206                                 $this->checkpointFiles[] = $val;
 207                                 break;
 208                         case 'current':
 209                                 $this->history = WikiExporter::CURRENT;
 210                                 break;
 211                         case 'full':
 212                                 $this->history = WikiExporter::FULL;
 213                                 break;
 214                         case 'spawn':
 215                                 $this->spawn = true;
 216                                 if ( $val ) {
 217                                         $this->php = $val;
 218                                 }
 219                                 break;
 220                 }
 221         }
 222
 223         function processFileOpt( $val, $param ) {
 224                 $fileURIs = explode( ';', $param );
 225                 foreach ( $fileURIs as $URI ) {
 226                         switch ( $val ) {
 227                                 case "file":
 228                                         $newURI = $URI;
 229                                         break;
 230                                 case "gzip":
 231                                         $newURI = "compress.zlib://$URI";
 232                                         break;
 233                                 case "bzip2":
 234                                         $newURI = "compress.bzip2://$URI";
 235                                         break;
 236                                 case "7zip":
 237                                         $newURI = "mediawiki.compress.7z://$URI";
 238                                         break;
 239                                 default:
 240                                         $newURI = $URI;
 241                         }
 242                         $newFileURIs[] = $newURI;
 243                 }
 244                 $val = implode( ';', $newFileURIs );
 245
 246                 return $val;
 247         }
 248
 249         /**
 250          * Overridden to include prefetch ratio if enabled.
 251          */
 252         function showReport() {
 253                 if ( !$this->prefetch ) {
 254                         parent::showReport();
 255
 256                         return;
 257                 }
 258
 259                 if ( $this->reporting ) {
 260                         $now = wfTimestamp( TS_DB );
 261                         $nowts = microtime( true );
 262                         $deltaAll = $nowts - $this->startTime;
 263                         $deltaPart = $nowts - $this->lastTime;
 264                         $this->pageCountPart = $this->pageCount - $this->pageCountLast;
 265                         $this->revCountPart = $this->revCount - $this->revCountLast;
 266
 267                         if ( $deltaAll ) {
 268                                 $portion = $this->revCount / $this->maxCount;
 269                                 $eta = $this->startTime + $deltaAll / $portion;
 270                                 $etats = wfTimestamp( TS_DB, intval( $eta ) );
 271                                 if ( $this->fetchCount ) {
 272                                         $fetchRate = 100.0 * $this->prefetchCount / $this->fetchCount;
 273                                 } else {
 274                                         $fetchRate = '-';
 275                                 }
 276                                 $pageRate = $this->pageCount / $deltaAll;
 277                                 $revRate = $this->revCount / $deltaAll;
 278                         } else {
 279                                 $pageRate = '-';
 280                                 $revRate = '-';
 281                                 $etats = '-';
 282                                 $fetchRate = '-';
 283                         }
 284                         if ( $deltaPart ) {
 285                                 if ( $this->fetchCountLast ) {
 286                                         $fetchRatePart = 100.0 * $this->prefetchCountLast / $this->fetchCountLast;
 287                                 } else {
 288                                         $fetchRatePart = '-';
 289                                 }
 290                                 $pageRatePart = $this->pageCountPart / $deltaPart;
 291                                 $revRatePart = $this->revCountPart / $deltaPart;
 292                         } else {
 293                                 $fetchRatePart = '-';
 294                                 $pageRatePart = '-';
 295                                 $revRatePart = '-';
 296                         }
 297                         $this->progress( sprintf(
 298                                 "%s: %s (ID %d) %d pages (%0.1f|%0.1f/sec all|curr), "
 299                                         . "%d revs (%0.1f|%0.1f/sec all|curr), %0.1f%%|%0.1f%% "
 300                                         . "prefetched (all|curr), ETA %s [max %d]",
 301                                 $now, wfWikiID(), $this->ID, $this->pageCount, $pageRate,
 302                                 $pageRatePart, $this->revCount, $revRate, $revRatePart,
 303                                 $fetchRate, $fetchRatePart, $etats, $this->maxCount
 304                         ) );
 305                         $this->lastTime = $nowts;
 306                         $this->revCountLast = $this->revCount;
 307                         $this->prefetchCountLast = $this->prefetchCount;
 308                         $this->fetchCountLast = $this->fetchCount;
 309                 }
 310         }
 311
 312         function setTimeExceeded() {
 313                 $this->timeExceeded = true;
 314         }
 315
 316         function checkIfTimeExceeded() {
 317                 if ( $this->maxTimeAllowed
 318                         && ( $this->lastTime - $this->timeOfCheckpoint > $this->maxTimeAllowed )
 319                 ) {
 320                         return true;
 321                 }
 322
 323                 return false;
 324         }
 325
 326         function finalOptionCheck() {
 327                 if ( ( $this->checkpointFiles && !$this->maxTimeAllowed )
 328                         || ( $this->maxTimeAllowed && !$this->checkpointFiles )
 329                 ) {
 330                         throw new MWException( "Options checkpointfile and maxtime must be specified together.\n" );
 331                 }
 332                 foreach ( $this->checkpointFiles as $checkpointFile ) {
 333                         $count = substr_count( $checkpointFile, "%s" );
 334                         if ( $count != 2 ) {
 335                                 throw new MWException( "Option checkpointfile must contain two '%s' "
 336                                         . "for substitution of first and last pageids, count is $count instead, "
 337                                         . "file is $checkpointFile.\n" );
 338                         }
 339                 }
 340
 341                 if ( $this->checkpointFiles ) {
 342                         $filenameList = (array)$this->egress->getFilenames();
 343                         if ( count( $filenameList ) != count( $this->checkpointFiles ) ) {
 344                                 throw new MWException( "One checkpointfile must be specified "
 345                                         . "for each output option, if maxtime is used.\n" );
 346                         }
 347                 }
 348         }
 349
 350         /**
 351          * @throws MWException Failure to parse XML input
 352          * @param string $input
 353          * @return bool
 354          */
 355         function readDump( $input ) {
 356                 $this->buffer = "";
 357                 $this->openElement = false;
 358                 $this->atStart = true;
 359                 $this->state = "";
 360                 $this->lastName = "";
 361                 $this->thisPage = 0;
 362                 $this->thisRev = 0;
 363                 $this->thisRevModel = null;
 364                 $this->thisRevFormat = null;
 365
 366                 $parser = xml_parser_create( "UTF-8" );
 367                 xml_parser_set_option( $parser, XML_OPTION_CASE_FOLDING, false );
 368
 369                 xml_set_element_handler(
 370                         $parser,
 371                         array( &$this, 'startElement' ),
 372                         array( &$this, 'endElement' )
 373                 );
 374                 xml_set_character_data_handler( $parser, array( &$this, 'characterData' ) );
 375
 376                 $offset = 0; // for context extraction on error reporting
 377                 do {
 378                         if ( $this->checkIfTimeExceeded() ) {
 379                                 $this->setTimeExceeded();
 380                         }
 381                         $chunk = fread( $input, $this->bufferSize );
 382                         if ( !xml_parse( $parser, $chunk, feof( $input ) ) ) {
 383                                 wfDebug( "TextDumpPass::readDump encountered XML parsing error\n" );
 384
 385                                 $byte = xml_get_current_byte_index( $parser );
 386                                 $msg = wfMessage( 'xml-error-string',
 387                                         'XML import parse failure',
 388                                         xml_get_current_line_number( $parser ),
 389                                         xml_get_current_column_number( $parser ),
 390                                         $byte . ( is_null( $chunk ) ? null : ( '; "' . substr( $chunk, $byte - $offset, 16 ) . '"' ) ),
 391                                         xml_error_string( xml_get_error_code( $parser ) ) )->escaped();
 392
 393                                 xml_parser_free( $parser );
 394
 395                                 throw new MWException( $msg );
 396                         }
 397                         $offset += strlen( $chunk );
 398                 } while ( $chunk !== false && !feof( $input ) );
 399                 if ( $this->maxTimeAllowed ) {
 400                         $filenameList = (array)$this->egress->getFilenames();
 401                         // we wrote some stuff after last checkpoint that needs renamed
 402                         if ( file_exists( $filenameList[0] ) ) {
 403                                 $newFilenames = array();
 404                                 # we might have just written the header and footer and had no
 405                                 # pages or revisions written... perhaps they were all deleted
 406                                 # there's no pageID 0 so we use that. the caller is responsible
 407                                 # for deciding what to do with a file containing only the
 408                                 # siteinfo information and the mw tags.
 409                                 if ( !$this->firstPageWritten ) {
 410                                         $firstPageID = str_pad( 0, 9, "0", STR_PAD_LEFT );
 411                                         $lastPageID = str_pad( 0, 9, "0", STR_PAD_LEFT );
 412                                 } else {
 413                                         $firstPageID = str_pad( $this->firstPageWritten, 9, "0", STR_PAD_LEFT );
 414                                         $lastPageID = str_pad( $this->lastPageWritten, 9, "0", STR_PAD_LEFT );
 415                                 }
 416
 417                                 $filenameCount = count( $filenameList );
 418                                 for ( $i = 0; $i < $filenameCount; $i++ ) {
 419                                         $checkpointNameFilledIn = sprintf( $this->checkpointFiles[$i], $firstPageID, $lastPageID );
 420                                         $fileinfo = pathinfo( $filenameList[$i] );
 421                                         $newFilenames[] = $fileinfo['dirname'] . '/' . $checkpointNameFilledIn;
 422                                 }
 423                                 $this->egress->closeAndRename( $newFilenames );
 424                         }
 425                 }
 426                 xml_parser_free( $parser );
 427
 428                 return true;
 429         }
 430
 431         /**
 432          * Applies applicable export transformations to $text.
 433          *
 434          * @param string $text
 435          * @param string $model
 436          * @param string|null $format
 437          *
 438          * @return string
 439          */
 440         private function exportTransform( $text, $model, $format = null ) {
 441                 try {
 442                         $handler = ContentHandler::getForModelID( $model );
 443                         $text = $handler->exportTransform( $text, $format );
 444                 }
 445                 catch ( MWException $ex ) {
 446                         $this->progress(
 447                                 "Unable to apply export transformation for content model '$model': " .
 448                                 $ex->getMessage()
 449                         );
 450                 }
 451
 452                 return $text;
 453         }
 454
 455         /**
 456          * Tries to get the revision text for a revision id.
 457          * Export transformations are applied if the content model can is given or can be
 458          * determined from the database.
 459          *
 460          * Upon errors, retries (Up to $this->maxFailures tries each call).
 461          * If still no good revision get could be found even after this retrying, "" is returned.
 462          * If no good revision text could be returned for
 463          * $this->maxConsecutiveFailedTextRetrievals consecutive calls to getText, MWException
 464          * is thrown.
 465          *
 466          * @param string $id The revision id to get the text for
 467          * @param string|bool|null $model The content model used to determine
 468          *  applicable export transformations.
 469          *  If $model is null, it will be determined from the database.
 470          * @param string|null $format The content format used when applying export transformations.
 471          *
 472          * @throws MWException
 473          * @return string The revision text for $id, or ""
 474          */
 475         function getText( $id, $model = null, $format = null ) {
 476                 global $wgContentHandlerUseDB;
 477
 478                 $prefetchNotTried = true; // Whether or not we already tried to get the text via prefetch.
 479                 $text = false; // The candidate for a good text. false if no proper value.
 480                 $failures = 0; // The number of times, this invocation of getText already failed.
 481
 482                 // The number of times getText failed without yielding a good text in between.
 483                 static $consecutiveFailedTextRetrievals = 0;
 484
 485                 $this->fetchCount++;
 486
 487                 // To allow to simply return on success and do not have to worry about book keeping,
 488                 // we assume, this fetch works (possible after some retries). Nevertheless, we koop
 489                 // the old value, so we can restore it, if problems occur (See after the while loop).
 490                 $oldConsecutiveFailedTextRetrievals = $consecutiveFailedTextRetrievals;
 491                 $consecutiveFailedTextRetrievals = 0;
 492
 493                 if ( $model === null && $wgContentHandlerUseDB ) {
 494                         $row = $this->db->selectRow(
 495                                 'revision',
 496                                 array( 'rev_content_model', 'rev_content_format' ),
 497                                 array( 'rev_id' => $this->thisRev ),
 498                                 __METHOD__
 499                         );
 500
 501                         if ( $row ) {
 502                                 $model = $row->rev_content_model;
 503                                 $format = $row->rev_content_format;
 504                         }
 505                 }
 506
 507                 if ( $model === null || $model === '' ) {
 508                         $model = false;
 509                 }
 510
 511                 while ( $failures < $this->maxFailures ) {
 512
 513                         // As soon as we found a good text for the $id, we will return immediately.
 514                         // Hence, if we make it past the try catch block, we know that we did not
 515                         // find a good text.
 516
 517                         try {
 518                                 // Step 1: Get some text (or reuse from previous iteratuon if checking
 519                                 //         for plausibility failed)
 520
 521                                 // Trying to get prefetch, if it has not been tried before
 522                                 if ( $text === false && isset( $this->prefetch ) && $prefetchNotTried ) {
 523                                         $prefetchNotTried = false;
 524                                         $tryIsPrefetch = true;
 525                                         $text = $this->prefetch->prefetch( intval( $this->thisPage ),
 526                                                 intval( $this->thisRev ) );
 527
 528                                         if ( $text === null ) {
 529                                                 $text = false;
 530                                         }
 531
 532                                         if ( is_string( $text ) && $model !== false ) {
 533                                                 // Apply export transformation to text coming from an old dump.
 534                                                 // The purpose of this transformation is to convert up from legacy
 535                                                 // formats, which may still be used in the older dump that is used
 536                                                 // for pre-fetching. Applying the transformation again should not
 537                                                 // interfere with content that is already in the correct form.
 538                                                 $text = $this->exportTransform( $text, $model, $format );
 539                                         }
 540                                 }
 541
 542                                 if ( $text === false ) {
 543                                         // Fallback to asking the database
 544                                         $tryIsPrefetch = false;
 545                                         if ( $this->spawn ) {
 546                                                 $text = $this->getTextSpawned( $id );
 547                                         } else {
 548                                                 $text = $this->getTextDb( $id );
 549                                         }
 550
 551                                         if ( $text !== false && $model !== false ) {
 552                                                 // Apply export transformation to text coming from the database.
 553                                                 // Prefetched text should already have transformations applied.
 554                                                 $text = $this->exportTransform( $text, $model, $format );
 555                                         }
 556
 557                                         // No more checks for texts from DB for now.
 558                                         // If we received something that is not false,
 559                                         // We treat it as good text, regardless of whether it actually is or is not
 560                                         if ( $text !== false ) {
 561                                                 return $text;
 562                                         }
 563                                 }
 564
 565                                 if ( $text === false ) {
 566                                         throw new MWException( "Generic error while obtaining text for id " . $id );
 567                                 }
 568
 569                                 // We received a good candidate for the text of $id via some method
 570
 571                                 // Step 2: Checking for plausibility and return the text if it is
 572                                 //         plausible
 573                                 $revID = intval( $this->thisRev );
 574                                 if ( !isset( $this->db ) ) {
 575                                         throw new MWException( "No database available" );
 576                                 }
 577
 578                                 if ( $model !== CONTENT_MODEL_WIKITEXT ) {
 579                                         $revLength = strlen( $text );
 580                                 } else {
 581                                         $revLength = $this->db->selectField( 'revision', 'rev_len', array( 'rev_id' => $revID ) );
 582                                 }
 583
 584                                 if ( strlen( $text ) == $revLength ) {
 585                                         if ( $tryIsPrefetch ) {
 586                                                 $this->prefetchCount++;
 587                                         }
 588
 589                                         return $text;
 590                                 }
 591
 592                                 $text = false;
 593                                 throw new MWException( "Received text is unplausible for id " . $id );
 594                         } catch ( Exception $e ) {
 595                                 $msg = "getting/checking text " . $id . " failed (" . $e->getMessage() . ")";
 596                                 if ( $failures + 1 < $this->maxFailures ) {
 597                                         $msg .= " (Will retry " . ( $this->maxFailures - $failures - 1 ) . " more times)";
 598                                 }
 599                                 $this->progress( $msg );
 600                         }
 601
 602                         // Something went wrong; we did not a text that was plausible :(
 603                         $failures++;
 604
 605                         // A failure in a prefetch hit does not warrant resetting db connection etc.
 606                         if ( !$tryIsPrefetch ) {
 607                                 // After backing off for some time, we try to reboot the whole process as
 608                                 // much as possible to not carry over failures from one part to the other
 609                                 // parts
 610                                 sleep( $this->failureTimeout );
 611                                 try {
 612                                         $this->rotateDb();
 613                                         if ( $this->spawn ) {
 614                                                 $this->closeSpawn();
 615                                                 $this->openSpawn();
 616                                         }
 617                                 } catch ( Exception $e ) {
 618                                         $this->progress( "Rebooting getText infrastructure failed (" . $e->getMessage() . ")" .
 619                                                 " Trying to continue anyways" );
 620                                 }
 621                         }
 622                 }
 623
 624                 // Retirieving a good text for $id failed (at least) maxFailures times.
 625                 // We abort for this $id.
 626
 627                 // Restoring the consecutive failures, and maybe aborting, if the dump
 628                 // is too broken.
 629                 $consecutiveFailedTextRetrievals = $oldConsecutiveFailedTextRetrievals + 1;
 630                 if ( $consecutiveFailedTextRetrievals > $this->maxConsecutiveFailedTextRetrievals ) {
 631                         throw new MWException( "Graceful storage failure" );
 632                 }
 633
 634                 return "";
 635         }
 636
 637         /**
 638          * May throw a database error if, say, the server dies during query.
 639          * @param int $id
 640          * @return bool|string
 641          * @throws MWException
 642          */
 643         private function getTextDb( $id ) {
 644                 global $wgContLang;
 645                 if ( !isset( $this->db ) ) {
 646                         throw new MWException( __METHOD__ . "No database available" );
 647                 }
 648                 $row = $this->db->selectRow( 'text',
 649                         array( 'old_text', 'old_flags' ),
 650                         array( 'old_id' => $id ),
 651                         __METHOD__ );
 652                 $text = Revision::getRevisionText( $row );
 653                 if ( $text === false ) {
 654                         return false;
 655                 }
 656                 $stripped = str_replace( "\r", "", $text );
 657                 $normalized = $wgContLang->normalize( $stripped );
 658
 659                 return $normalized;
 660         }
 661
 662         private function getTextSpawned( $id ) {
 663                 MediaWiki\suppressWarnings();
 664                 if ( !$this->spawnProc ) {
 665                         // First time?
 666                         $this->openSpawn();
 667                 }
 668                 $text = $this->getTextSpawnedOnce( $id );
 669                 MediaWiki\restoreWarnings();
 670
 671                 return $text;
 672         }
 673
 674         function openSpawn() {
 675                 global $IP;
 676
 677                 if ( file_exists( "$IP/../multiversion/MWScript.php" ) ) {
 678                         $cmd = implode( " ",
 679                                 array_map( 'wfEscapeShellArg',
 680                                         array(
 681                                                 $this->php,
 682                                                 "$IP/../multiversion/MWScript.php",
 683                                                 "fetchText.php",
 684                                                 '--wiki', wfWikiID() ) ) );
 685                 } else {
 686                         $cmd = implode( " ",
 687                                 array_map( 'wfEscapeShellArg',
 688                                         array(
 689                                                 $this->php,
 690                                                 "$IP/maintenance/fetchText.php",
 691                                                 '--wiki', wfWikiID() ) ) );
 692                 }
 693                 $spec = array(
 694                         0 => array( "pipe", "r" ),
 695                         1 => array( "pipe", "w" ),
 696                         2 => array( "file", "/dev/null", "a" ) );
 697                 $pipes = array();
 698
 699                 $this->progress( "Spawning database subprocess: $cmd" );
 700                 $this->spawnProc = proc_open( $cmd, $spec, $pipes );
 701                 if ( !$this->spawnProc ) {
 702                         // shit
 703                         $this->progress( "Subprocess spawn failed." );
 704
 705                         return false;
 706                 }
 707                 list(
 708                         $this->spawnWrite, // -> stdin
 709                         $this->spawnRead, // <- stdout
 710                 ) = $pipes;
 711
 712                 return true;
 713         }
 714
 715         private function closeSpawn() {
 716                 MediaWiki\suppressWarnings();
 717                 if ( $this->spawnRead ) {
 718                         fclose( $this->spawnRead );
 719                 }
 720                 $this->spawnRead = false;
 721                 if ( $this->spawnWrite ) {
 722                         fclose( $this->spawnWrite );
 723                 }
 724                 $this->spawnWrite = false;
 725                 if ( $this->spawnErr ) {
 726                         fclose( $this->spawnErr );
 727                 }
 728                 $this->spawnErr = false;
 729                 if ( $this->spawnProc ) {
 730                         pclose( $this->spawnProc );
 731                 }
 732                 $this->spawnProc = false;
 733                 MediaWiki\restoreWarnings();
 734         }
 735
 736         private function getTextSpawnedOnce( $id ) {
 737                 global $wgContLang;
 738
 739                 $ok = fwrite( $this->spawnWrite, "$id\n" );
 740                 // $this->progress( ">> $id" );
 741                 if ( !$ok ) {
 742                         return false;
 743                 }
 744
 745                 $ok = fflush( $this->spawnWrite );
 746                 // $this->progress( ">> [flush]" );
 747                 if ( !$ok ) {
 748                         return false;
 749                 }
 750
 751                 // check that the text id they are sending is the one we asked for
 752                 // this avoids out of sync revision text errors we have encountered in the past
 753                 $newId = fgets( $this->spawnRead );
 754                 if ( $newId === false ) {
 755                         return false;
 756                 }
 757                 if ( $id != intval( $newId ) ) {
 758                         return false;
 759                 }
 760
 761                 $len = fgets( $this->spawnRead );
 762                 // $this->progress( "<< " . trim( $len ) );
 763                 if ( $len === false ) {
 764                         return false;
 765                 }
 766
 767                 $nbytes = intval( $len );
 768                 // actual error, not zero-length text
 769                 if ( $nbytes < 0 ) {
 770                         return false;
 771                 }
 772
 773                 $text = "";
 774
 775                 // Subprocess may not send everything at once, we have to loop.
 776                 while ( $nbytes > strlen( $text ) ) {
 777                         $buffer = fread( $this->spawnRead, $nbytes - strlen( $text ) );
 778                         if ( $buffer === false ) {
 779                                 break;
 780                         }
 781                         $text .= $buffer;
 782                 }
 783
 784                 $gotbytes = strlen( $text );
 785                 if ( $gotbytes != $nbytes ) {
 786                         $this->progress( "Expected $nbytes bytes from database subprocess, got $gotbytes " );
 787
 788                         return false;
 789                 }
 790
 791                 // Do normalization in the dump thread...
 792                 $stripped = str_replace( "\r", "", $text );
 793                 $normalized = $wgContLang->normalize( $stripped );
 794
 795                 return $normalized;
 796         }
 797
 798         function startElement( $parser, $name, $attribs ) {
 799                 $this->checkpointJustWritten = false;
 800
 801                 $this->clearOpenElement( null );
 802                 $this->lastName = $name;
 803
 804                 if ( $name == 'revision' ) {
 805                         $this->state = $name;
 806                         $this->egress->writeOpenPage( null, $this->buffer );
 807                         $this->buffer = "";
 808                 } elseif ( $name == 'page' ) {
 809                         $this->state = $name;
 810                         if ( $this->atStart ) {
 811                                 $this->egress->writeOpenStream( $this->buffer );
 812                                 $this->buffer = "";
 813                                 $this->atStart = false;
 814                         }
 815                 }
 816
 817                 if ( $name == "text" && isset( $attribs['id'] ) ) {
 818                         $id = $attribs['id'];
 819                         $model = trim( $this->thisRevModel );
 820                         $format = trim( $this->thisRevFormat );
 821
 822                         $model = $model === '' ? null : $model;
 823                         $format = $format === '' ? null : $format;
 824
 825                         $text = $this->getText( $id, $model, $format );
 826                         $this->openElement = array( $name, array( 'xml:space' => 'preserve' ) );
 827                         if ( strlen( $text ) > 0 ) {
 828                                 $this->characterData( $parser, $text );
 829                         }
 830                 } else {
 831                         $this->openElement = array( $name, $attribs );
 832                 }
 833         }
 834
 835         function endElement( $parser, $name ) {
 836                 $this->checkpointJustWritten = false;
 837
 838                 if ( $this->openElement ) {
 839                         $this->clearOpenElement( "" );
 840                 } else {
 841                         $this->buffer .= "</$name>";
 842                 }
 843
 844                 if ( $name == 'revision' ) {
 845                         $this->egress->writeRevision( null, $this->buffer );
 846                         $this->buffer = "";
 847                         $this->thisRev = "";
 848                         $this->thisRevModel = null;
 849                         $this->thisRevFormat = null;
 850                 } elseif ( $name == 'page' ) {
 851                         if ( !$this->firstPageWritten ) {
 852                                 $this->firstPageWritten = trim( $this->thisPage );
 853                         }
 854                         $this->lastPageWritten = trim( $this->thisPage );
 855                         if ( $this->timeExceeded ) {
 856                                 $this->egress->writeClosePage( $this->buffer );
 857                                 // nasty hack, we can't just write the chardata after the
 858                                 // page tag, it will include leading blanks from the next line
 859                                 $this->egress->sink->write( "\n" );
 860
 861                                 $this->buffer = $this->xmlwriterobj->closeStream();
 862                                 $this->egress->writeCloseStream( $this->buffer );
 863
 864                                 $this->buffer = "";
 865                                 $this->thisPage = "";
 866                                 // this could be more than one file if we had more than one output arg
 867
 868                                 $filenameList = (array)$this->egress->getFilenames();
 869                                 $newFilenames = array();
 870                                 $firstPageID = str_pad( $this->firstPageWritten, 9, "0", STR_PAD_LEFT );
 871                                 $lastPageID = str_pad( $this->lastPageWritten, 9, "0", STR_PAD_LEFT );
 872                                 $filenamesCount = count( $filenameList );
 873                                 for ( $i = 0; $i < $filenamesCount; $i++ ) {
 874                                         $checkpointNameFilledIn = sprintf( $this->checkpointFiles[$i], $firstPageID, $lastPageID );
 875                                         $fileinfo = pathinfo( $filenameList[$i] );
 876                                         $newFilenames[] = $fileinfo['dirname'] . '/' . $checkpointNameFilledIn;
 877                                 }
 878                                 $this->egress->closeRenameAndReopen( $newFilenames );
 879                                 $this->buffer = $this->xmlwriterobj->openStream();
 880                                 $this->timeExceeded = false;
 881                                 $this->timeOfCheckpoint = $this->lastTime;
 882                                 $this->firstPageWritten = false;
 883                                 $this->checkpointJustWritten = true;
 884                         } else {
 885                                 $this->egress->writeClosePage( $this->buffer );
 886                                 $this->buffer = "";
 887                                 $this->thisPage = "";
 888                         }
 889                 } elseif ( $name == 'mediawiki' ) {
 890                         $this->egress->writeCloseStream( $this->buffer );
 891                         $this->buffer = "";
 892                 }
 893         }
 894
 895         function characterData( $parser, $data ) {
 896                 $this->clearOpenElement( null );
 897                 if ( $this->lastName == "id" ) {
 898                         if ( $this->state == "revision" ) {
 899                                 $this->thisRev .= $data;
 900                         } elseif ( $this->state == "page" ) {
 901                                 $this->thisPage .= $data;
 902                         }
 903                 }
 904                 elseif ( $this->lastName == "model" ) {
 905                         $this->thisRevModel .= $data;
 906                 }
 907                 elseif ( $this->lastName == "format" ) {
 908                         $this->thisRevFormat .= $data;
 909                 }
 910
 911                 // have to skip the newline left over from closepagetag line of
 912                 // end of checkpoint files. nasty hack!!
 913                 if ( $this->checkpointJustWritten ) {
 914                         if ( $data[0] == "\n" ) {
 915                                 $data = substr( $data, 1 );
 916                         }
 917                         $this->checkpointJustWritten = false;
 918                 }
 919                 $this->buffer .= htmlspecialchars( $data );
 920         }
 921
 922         function clearOpenElement( $style ) {
 923                 if ( $this->openElement ) {
 924                         $this->buffer .= Xml::element( $this->openElement[0], $this->openElement[1], $style );
 925                         $this->openElement = false;
 926                 }
 927         }
 928 }