includes/installer/DatabaseUpdater.php

   1 <?php
   2 /**
   3  * DBMS-specific updater helper.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Deployment
  22  */
  23
  24 require_once( __DIR__ . '/../../maintenance/Maintenance.php' );
  25
  26 /**
  27  * Class for handling database updates. Roughly based off of updaters.inc, with
  28  * a few improvements :)
  29  *
  30  * @ingroup Deployment
  31  * @since 1.17
  32  */
  33 abstract class DatabaseUpdater {
  34
  35         /**
  36          * Array of updates to perform on the database
  37          *
  38          * @var array
  39          */
  40         protected $updates = array();
  41
  42         /**
  43          * Array of updates that were skipped
  44          *
  45          * @var array
  46          */
  47         protected $updatesSkipped = array();
  48
  49         /**
  50          * List of extension-provided database updates
  51          * @var array
  52          */
  53         protected $extensionUpdates = array();
  54
  55         /**
  56          * Handle to the database subclass
  57          *
  58          * @var DatabaseBase
  59          */
  60         protected $db;
  61
  62         protected $shared = false;
  63
  64         /**
  65          * Scripts to run after database update
  66          * Should be a subclass of LoggedUpdateMaintenance
  67          */
  68         protected $postDatabaseUpdateMaintenance = array(
  69                 'DeleteDefaultMessages',
  70                 'PopulateRevisionLength',
  71                 'PopulateRevisionSha1',
  72                 'PopulateImageSha1',
  73                 'FixExtLinksProtocolRelative',
  74                 'PopulateFilearchiveSha1',
  75         );
  76
  77         /**
  78          * File handle for SQL output.
  79          *
  80          * @var Filehandle
  81          */
  82         protected $fileHandle = null;
  83
  84         /**
  85          * Flag specifying whether or not to skip schema (e.g. SQL-only) updates.
  86          *
  87          * @var bool
  88          */
  89         protected $skipSchema = false;
  90
  91         /**
  92          * Constructor
  93          *
  94          * @param $db DatabaseBase object to perform updates on
  95          * @param $shared bool Whether to perform updates on shared tables
  96          * @param $maintenance Maintenance Maintenance object which created us
  97          */
  98         protected function __construct( DatabaseBase &$db, $shared, Maintenance $maintenance = null ) {
  99                 $this->db = $db;
 100                 $this->db->setFlag( DBO_DDLMODE ); // For Oracle's handling of schema files
 101                 $this->shared = $shared;
 102                 if ( $maintenance ) {
 103                         $this->maintenance = $maintenance;
 104                         $this->fileHandle = $maintenance->fileHandle;
 105                 } else {
 106                         $this->maintenance = new FakeMaintenance;
 107                 }
 108                 $this->maintenance->setDB( $db );
 109                 $this->initOldGlobals();
 110                 $this->loadExtensions();
 111                 wfRunHooks( 'LoadExtensionSchemaUpdates', array( $this ) );
 112         }
 113
 114         /**
 115          * Initialize all of the old globals. One day this should all become
 116          * something much nicer
 117          */
 118         private function initOldGlobals() {
 119                 global $wgExtNewTables, $wgExtNewFields, $wgExtPGNewFields,
 120                         $wgExtPGAlteredFields, $wgExtNewIndexes, $wgExtModifiedFields;
 121
 122                 # For extensions only, should be populated via hooks
 123                 # $wgDBtype should be checked to specifiy the proper file
 124                 $wgExtNewTables = array(); // table, dir
 125                 $wgExtNewFields = array(); // table, column, dir
 126                 $wgExtPGNewFields = array(); // table, column, column attributes; for PostgreSQL
 127                 $wgExtPGAlteredFields = array(); // table, column, new type, conversion method; for PostgreSQL
 128                 $wgExtNewIndexes = array(); // table, index, dir
 129                 $wgExtModifiedFields = array(); // table, index, dir
 130         }
 131
 132         /**
 133          * Loads LocalSettings.php, if needed, and initialises everything needed for LoadExtensionSchemaUpdates hook
 134          */
 135         private function loadExtensions() {
 136                 if ( !defined( 'MEDIAWIKI_INSTALL' ) ) {
 137                         return; // already loaded
 138                 }
 139                 $vars = Installer::getExistingLocalSettings();
 140                 if ( !$vars ) {
 141                         return; // no LocalSettings found
 142                 }
 143                 if ( !isset( $vars['wgHooks'] ) || !isset( $vars['wgHooks']['LoadExtensionSchemaUpdates'] ) ) {
 144                         return;
 145                 }
 146                 global $wgHooks, $wgAutoloadClasses;
 147                 $wgHooks['LoadExtensionSchemaUpdates'] = $vars['wgHooks']['LoadExtensionSchemaUpdates'];
 148                 $wgAutoloadClasses = $wgAutoloadClasses + $vars['wgAutoloadClasses'];
 149         }
 150
 151         /**
 152          * @throws MWException
 153          * @param DatabaseBase $db
 154          * @param bool $shared
 155          * @param null $maintenance
 156          * @return DatabaseUpdater
 157          */
 158         public static function newForDB( &$db, $shared = false, $maintenance = null ) {
 159                 $type = $db->getType();
 160                 if( in_array( $type, Installer::getDBTypes() ) ) {
 161                         $class = ucfirst( $type ) . 'Updater';
 162                         return new $class( $db, $shared, $maintenance );
 163                 } else {
 164                         throw new MWException( __METHOD__ . ' called for unsupported $wgDBtype' );
 165                 }
 166         }
 167
 168         /**
 169          * Get a database connection to run updates
 170          *
 171          * @return DatabaseBase
 172          */
 173         public function getDB() {
 174                 return $this->db;
 175         }
 176
 177         /**
 178          * Output some text. If we're running from web, escape the text first.
 179          *
 180          * @param $str String: Text to output
 181          */
 182         public function output( $str ) {
 183                 if ( $this->maintenance->isQuiet() ) {
 184                         return;
 185                 }
 186                 global $wgCommandLineMode;
 187                 if( !$wgCommandLineMode ) {
 188                         $str = htmlspecialchars( $str );
 189                 }
 190                 echo $str;
 191                 flush();
 192         }
 193
 194         /**
 195          * Add a new update coming from an extension. This should be called by
 196          * extensions while executing the LoadExtensionSchemaUpdates hook.
 197          *
 198          * @since 1.17
 199          *
 200          * @param $update Array: the update to run. Format is the following:
 201          *                first item is the callback function, it also can be a
 202          *                simple string with the name of a function in this class,
 203          *                following elements are parameters to the function.
 204          *                Note that callback functions will receive this object as
 205          *                first parameter.
 206          */
 207         public function addExtensionUpdate( array $update ) {
 208                 $this->extensionUpdates[] = $update;
 209         }
 210
 211         /**
 212          * Convenience wrapper for addExtensionUpdate() when adding a new table (which
 213          * is the most common usage of updaters in an extension)
 214          *
 215          * @since 1.18
 216          *
 217          * @param $tableName String Name of table to create
 218          * @param $sqlPath String Full path to the schema file
 219          */
 220         public function addExtensionTable( $tableName, $sqlPath ) {
 221                 $this->extensionUpdates[] = array( 'addTable', $tableName, $sqlPath, true );
 222         }
 223
 224         /**
 225          * @since 1.19
 226          *
 227          * @param $tableName string
 228          * @param $indexName string
 229          * @param $sqlPath string
 230          */
 231         public function addExtensionIndex( $tableName, $indexName, $sqlPath ) {
 232                 $this->extensionUpdates[] = array( 'addIndex', $tableName, $indexName, $sqlPath, true );
 233         }
 234
 235         /**
 236          *
 237          * @since 1.19
 238          *
 239          * @param $tableName string
 240          * @param $columnName string
 241          * @param $sqlPath string
 242          */
 243         public function addExtensionField( $tableName, $columnName, $sqlPath ) {
 244                 $this->extensionUpdates[] = array( 'addField', $tableName, $columnName, $sqlPath, true );
 245         }
 246
 247         /**
 248          *
 249          * @since 1.20
 250          *
 251          * @param $tableName string
 252          * @param $columnName string
 253          * @param $sqlPath string
 254          */
 255         public function dropExtensionField( $tableName, $columnName, $sqlPath ) {
 256                 $this->extensionUpdates[] = array( 'dropField', $tableName, $columnName, $sqlPath, true );
 257         }
 258
 259         /**
 260          *
 261          * @since 1.20
 262          *
 263          * @param $tableName string
 264          * @param $sqlPath string
 265          */
 266         public function dropExtensionTable( $tableName, $sqlPath ) {
 267                 $this->extensionUpdates[] = array( 'dropTable', $tableName, $sqlPath, true );
 268         }
 269
 270         /**
 271          *
 272          * @since 1.20
 273          *
 274          * @param $tableName string
 275          * @return bool
 276          */
 277         public function tableExists( $tableName ) {
 278                 return ( $this->db->tableExists( $tableName, __METHOD__ ) );
 279         }
 280
 281         /**
 282          * Add a maintenance script to be run after the database updates are complete.
 283          *
 284          * Script should subclass LoggedUpdateMaintenance
 285          *
 286          * @since 1.19
 287          *
 288          * @param $class string Name of a Maintenance subclass
 289          */
 290         public function addPostDatabaseUpdateMaintenance( $class ) {
 291                 $this->postDatabaseUpdateMaintenance[] = $class;
 292         }
 293
 294         /**
 295          * Get the list of extension-defined updates
 296          *
 297          * @return Array
 298          */
 299         protected function getExtensionUpdates() {
 300                 return $this->extensionUpdates;
 301         }
 302
 303         /**
 304          * @since 1.17
 305          *
 306          * @return array
 307          */
 308         public function getPostDatabaseUpdateMaintenance() {
 309                 return $this->postDatabaseUpdateMaintenance;
 310         }
 311
 312         /**
 313          * @since 1.21
 314          *
 315          * Writes the schema updates desired to a file for the DB Admin to run.
 316          */
 317         private function writeSchemaUpdateFile( $schemaUpdate = array() ) {
 318                 $updates = $this->updatesSkipped;
 319                 $this->updatesSkipped = array();
 320
 321                 foreach( $updates as $funcList ) {
 322                         $func = $funcList[0];
 323                         $arg = $funcList[1];
 324                         $origParams = $funcList[2];
 325                         $ret = call_user_func_array( $func, $arg );
 326                         flush();
 327                         $this->updatesSkipped[] = $origParams;
 328                 }
 329         }
 330
 331         /**
 332          * Do all the updates
 333          *
 334          * @param $what Array: what updates to perform
 335          */
 336         public function doUpdates( $what = array( 'core', 'extensions', 'stats' ) ) {
 337                 global $wgVersion, $wgLocalisationCacheConf;
 338
 339                 $this->db->begin( __METHOD__ );
 340                 $what = array_flip( $what );
 341                 $this->skipSchema = isset( $what['noschema'] ) || $this->fileHandle !== null;
 342                 if ( isset( $what['core'] ) ) {
 343                         $this->runUpdates( $this->getCoreUpdateList(), false );
 344                 }
 345                 if ( isset( $what['extensions'] ) ) {
 346                         $this->runUpdates( $this->getOldGlobalUpdates(), false );
 347                         $this->runUpdates( $this->getExtensionUpdates(), true );
 348                 }
 349
 350                 if ( isset( $what['stats'] ) ) {
 351                         $this->checkStats();
 352                 }
 353
 354                 if ( isset( $what['purge'] ) ) {
 355                         $this->purgeCache();
 356
 357                         if ( $wgLocalisationCacheConf['manualRecache'] ) {
 358                                 $this->rebuildLocalisationCache();
 359                         }
 360                 }
 361
 362                 $this->setAppliedUpdates( $wgVersion, $this->updates );
 363
 364                 if( $this->fileHandle ) {
 365                         $this->skipSchema = false;
 366                         $this->writeSchemaUpdateFile( );
 367                         $this->setAppliedUpdates( "$wgVersion-schema", $this->updatesSkipped );
 368                 }
 369
 370                 $this->db->commit( __METHOD__ );
 371         }
 372
 373         /**
 374          * Helper function for doUpdates()
 375          *
 376          * @param $updates Array of updates to run
 377          * @param $passSelf Boolean: whether to pass this object we calling external
 378          *                  functions
 379          */
 380         private function runUpdates( array $updates, $passSelf ) {
 381                 $updatesDone = array();
 382                 $updatesSkipped = array();
 383                 foreach ( $updates as $params ) {
 384                         $origParams = $params;
 385                         $func = array_shift( $params );
 386                         if( !is_array( $func ) && method_exists( $this, $func ) ) {
 387                                 $func = array( $this, $func );
 388                         } elseif ( $passSelf ) {
 389                                 array_unshift( $params, $this );
 390                         }
 391                         $ret = call_user_func_array( $func, $params );
 392                         flush();
 393                         if( $ret !== false ) {
 394                                 $updatesDone[] = $origParams;
 395                         } else {
 396                                 $updatesSkipped[] = array( $func, $params, $origParams );
 397                         }
 398                 }
 399                 $this->updatesSkipped = array_merge( $this->updatesSkipped, $updatesSkipped );
 400                 $this->updates = array_merge( $this->updates, $updatesDone );
 401         }
 402
 403         /**
 404          * @param $version
 405          * @param $updates array
 406          */
 407         protected function setAppliedUpdates( $version, $updates = array() ) {
 408                 $this->db->clearFlag( DBO_DDLMODE );
 409                 if( !$this->canUseNewUpdatelog() ) {
 410                         return;
 411                 }
 412                 $key = "updatelist-$version-" . time();
 413                 $this->db->insert( 'updatelog',
 414                         array( 'ul_key' => $key, 'ul_value' => serialize( $updates ) ),
 415                          __METHOD__ );
 416                 $this->db->setFlag( DBO_DDLMODE );
 417         }
 418
 419         /**
 420          * Helper function: check if the given key is present in the updatelog table.
 421          * Obviously, only use this for updates that occur after the updatelog table was
 422          * created!
 423          * @param $key String Name of the key to check for
 424          *
 425          * @return bool
 426          */
 427         public function updateRowExists( $key ) {
 428                 $row = $this->db->selectRow(
 429                         'updatelog',
 430                         '1',
 431                         array( 'ul_key' => $key ),
 432                         __METHOD__
 433                 );
 434                 return (bool)$row;
 435         }
 436
 437         /**
 438          * Helper function: Add a key to the updatelog table
 439          * Obviously, only use this for updates that occur after the updatelog table was
 440          * created!
 441          * @param $key String Name of key to insert
 442          * @param $val String [optional] value to insert along with the key
 443          */
 444         public function insertUpdateRow( $key, $val = null ) {
 445                 $this->db->clearFlag( DBO_DDLMODE );
 446                 $values = array( 'ul_key' => $key );
 447                 if( $val && $this->canUseNewUpdatelog() ) {
 448                         $values['ul_value'] = $val;
 449                 }
 450                 $this->db->insert( 'updatelog', $values, __METHOD__, 'IGNORE' );
 451                 $this->db->setFlag( DBO_DDLMODE );
 452         }
 453
 454         /**
 455          * Updatelog was changed in 1.17 to have a ul_value column so we can record
 456          * more information about what kind of updates we've done (that's what this
 457          * class does). Pre-1.17 wikis won't have this column, and really old wikis
 458          * might not even have updatelog at all
 459          *
 460          * @return boolean
 461          */
 462         protected function canUseNewUpdatelog() {
 463                 return $this->db->tableExists( 'updatelog', __METHOD__ ) &&
 464                         $this->db->fieldExists( 'updatelog', 'ul_value', __METHOD__ );
 465         }
 466
 467         /**
 468          * Before 1.17, we used to handle updates via stuff like
 469          * $wgExtNewTables/Fields/Indexes. This is nasty :) We refactored a lot
 470          * of this in 1.17 but we want to remain back-compatible for a while. So
 471          * load up these old global-based things into our update list.
 472          *
 473          * @return array
 474          */
 475         protected function getOldGlobalUpdates() {
 476                 global $wgExtNewFields, $wgExtNewTables, $wgExtModifiedFields,
 477                         $wgExtNewIndexes, $wgSharedDB, $wgSharedTables;
 478
 479                 $doUser = $this->shared ?
 480                         $wgSharedDB && in_array( 'user', $wgSharedTables ) :
 481                         !$wgSharedDB || !in_array( 'user', $wgSharedTables );
 482
 483                 $updates = array();
 484
 485                 foreach ( $wgExtNewTables as $tableRecord ) {
 486                         $updates[] = array(
 487                                 'addTable', $tableRecord[0], $tableRecord[1], true
 488                         );
 489                 }
 490
 491                 foreach ( $wgExtNewFields as $fieldRecord ) {
 492                         if ( $fieldRecord[0] != 'user' || $doUser ) {
 493                                 $updates[] = array(
 494                                         'addField', $fieldRecord[0], $fieldRecord[1],
 495                                                 $fieldRecord[2], true
 496                                 );
 497                         }
 498                 }
 499
 500                 foreach ( $wgExtNewIndexes as $fieldRecord ) {
 501                         $updates[] = array(
 502                                 'addIndex', $fieldRecord[0], $fieldRecord[1],
 503                                         $fieldRecord[2], true
 504                         );
 505                 }
 506
 507                 foreach ( $wgExtModifiedFields as $fieldRecord ) {
 508                         $updates[] = array(
 509                                 'modifyField', $fieldRecord[0], $fieldRecord[1],
 510                                         $fieldRecord[2], true
 511                         );
 512                 }
 513
 514                 return $updates;
 515         }
 516
 517         /**
 518          * Get an array of updates to perform on the database. Should return a
 519          * multi-dimensional array. The main key is the MediaWiki version (1.12,
 520          * 1.13...) with the values being arrays of updates, identical to how
 521          * updaters.inc did it (for now)
 522          *
 523          * @return Array
 524          */
 525         protected abstract function getCoreUpdateList();
 526
 527         /**
 528          * Append an SQL fragment to the open file handle.
 529          *
 530          * @param $filename String: File name to open
 531          */
 532         public function copyFile( $filename ) {
 533                 $this->db->sourceFile( $filename, false, false, false,
 534                         array( $this, 'appendLine' )
 535                 );
 536         }
 537
 538         /**
 539          * Append a line to the open filehandle.  The line is assumed to
 540          * be a complete SQL statement.
 541          *
 542          * This is used as a callback for for sourceLine().
 543          *
 544          * @param $line String text to append to the file
 545          * @return Boolean false to skip actually executing the file
 546          * @throws MWException
 547          */
 548         public function appendLine( $line ) {
 549                 $line = rtrim( $line ) . ";\n";
 550                 if( fwrite( $this->fileHandle, $line ) === false ) {
 551                         throw new MWException( "trouble writing file" );
 552                 }
 553                 return false;
 554         }
 555
 556         /**
 557          * Applies a SQL patch
 558          * @param $path String Path to the patch file
 559          * @param $isFullPath Boolean Whether to treat $path as a relative or not
 560          * @param $msg String Description of the patch
 561          * @return boolean false if patch is skipped.
 562          */
 563         protected function applyPatch( $path, $isFullPath = false, $msg = null ) {
 564                 if ( $msg === null ) {
 565                         $msg = "Applying $path patch";
 566                 }
 567                 if ( $this->skipSchema ) {
 568                         $this->output( "...skipping schema change ($msg).\n" );
 569                         return false;
 570                 }
 571
 572                 $this->output( "$msg ..." );
 573
 574                 if ( !$isFullPath ) {
 575                         $path = $this->db->patchPath( $path );
 576                 }
 577                 if( $this->fileHandle !== null ) {
 578                         $this->copyFile( $path );
 579                 } else {
 580                         $this->db->sourceFile( $path );
 581                 }
 582                 $this->output( "done.\n" );
 583                 return true;
 584         }
 585
 586         /**
 587          * Add a new table to the database
 588          * @param $name String Name of the new table
 589          * @param $patch String Path to the patch file
 590          * @param $fullpath Boolean Whether to treat $patch path as a relative or not
 591          * @return Boolean false if this was skipped because schema changes are skipped
 592          */
 593         protected function addTable( $name, $patch, $fullpath = false ) {
 594                 if ( $this->db->tableExists( $name, __METHOD__ ) ) {
 595                         $this->output( "...$name table already exists.\n" );
 596                 } else {
 597                         return $this->applyPatch( $patch, $fullpath, "Creating $name table" );
 598                 }
 599                 return true;
 600         }
 601
 602         /**
 603          * Add a new field to an existing table
 604          * @param $table String Name of the table to modify
 605          * @param $field String Name of the new field
 606          * @param $patch String Path to the patch file
 607          * @param $fullpath Boolean Whether to treat $patch path as a relative or not
 608          * @return Boolean false if this was skipped because schema changes are skipped
 609          */
 610         protected function addField( $table, $field, $patch, $fullpath = false ) {
 611                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 612                         $this->output( "...$table table does not exist, skipping new field patch.\n" );
 613                 } elseif ( $this->db->fieldExists( $table, $field, __METHOD__ ) ) {
 614                         $this->output( "...have $field field in $table table.\n" );
 615                 } else {
 616                         return $this->applyPatch( $patch, $fullpath, "Adding $field field to table $table" );
 617                 }
 618                 return true;
 619         }
 620
 621         /**
 622          * Add a new index to an existing table
 623          * @param $table String Name of the table to modify
 624          * @param $index String Name of the new index
 625          * @param $patch String Path to the patch file
 626          * @param $fullpath Boolean Whether to treat $patch path as a relative or not
 627          * @return Boolean false if this was skipped because schema changes are skipped
 628          */
 629         protected function addIndex( $table, $index, $patch, $fullpath = false ) {
 630                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 631                         $this->output( "...skipping: '$table' table doesn't exist yet.\n" );
 632                         return false;
 633                 } else if ( $this->db->indexExists( $table, $index, __METHOD__ ) ) {
 634                         $this->output( "...index $index already set on $table table.\n" );
 635                 } else {
 636                         return $this->applyPatch( $patch, $fullpath, "Adding index $index to table $table" );
 637                 }
 638                 return true;
 639         }
 640
 641         /**
 642          * Drop a field from an existing table
 643          *
 644          * @param $table String Name of the table to modify
 645          * @param $field String Name of the old field
 646          * @param $patch String Path to the patch file
 647          * @param $fullpath Boolean Whether to treat $patch path as a relative or not
 648          * @return Boolean false if this was skipped because schema changes are skipped
 649          */
 650         protected function dropField( $table, $field, $patch, $fullpath = false ) {
 651                 if ( $this->db->fieldExists( $table, $field, __METHOD__ ) ) {
 652                         return $this->applyPatch( $patch, $fullpath, "Table $table contains $field field. Dropping" );
 653                 } else {
 654                         $this->output( "...$table table does not contain $field field.\n" );
 655                 }
 656                 return true;
 657         }
 658
 659         /**
 660          * Drop an index from an existing table
 661          *
 662          * @param $table String: Name of the table to modify
 663          * @param $index String: Name of the old index
 664          * @param $patch String: Path to the patch file
 665          * @param $fullpath Boolean: Whether to treat $patch path as a relative or not
 666          * @return Boolean false if this was skipped because schema changes are skipped
 667          */
 668         protected function dropIndex( $table, $index, $patch, $fullpath = false ) {
 669                 if ( $this->db->indexExists( $table, $index, __METHOD__ ) ) {
 670                         return $this->applyPatch( $patch, $fullpath, "Dropping $index index from table $table" );
 671                 } else {
 672                         $this->output( "...$index key doesn't exist.\n" );
 673                 }
 674                 return true;
 675         }
 676
 677         /**
 678          * If the specified table exists, drop it, or execute the
 679          * patch if one is provided.
 680          *
 681          * Public @since 1.20
 682          *
 683          * @param $table string
 684          * @param $patch string|false
 685          * @param $fullpath bool
 686          * @return Boolean false if this was skipped because schema changes are skipped
 687          */
 688         public function dropTable( $table, $patch = false, $fullpath = false ) {
 689                 if ( $this->db->tableExists( $table, __METHOD__ ) ) {
 690                         $msg = "Dropping table $table";
 691
 692                         if ( $patch === false ) {
 693                                 $this->output( "$msg ..." );
 694                                 $this->db->dropTable( $table, __METHOD__ );
 695                                 $this->output( "done.\n" );
 696                         }
 697                         else {
 698                                 return $this->applyPatch( $patch, $fullpath, $msg );
 699                         }
 700                 } else {
 701                         $this->output( "...$table doesn't exist.\n" );
 702                 }
 703                 return true;
 704         }
 705
 706         /**
 707          * Modify an existing field
 708          *
 709          * @param $table String: name of the table to which the field belongs
 710          * @param $field String: name of the field to modify
 711          * @param $patch String: path to the patch file
 712          * @param $fullpath Boolean: whether to treat $patch path as a relative or not
 713          * @return Boolean false if this was skipped because schema changes are skipped
 714          */
 715         public function modifyField( $table, $field, $patch, $fullpath = false ) {
 716                 $updateKey = "$table-$field-$patch";
 717                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 718                         $this->output( "...$table table does not exist, skipping modify field patch.\n" );
 719                 } elseif ( !$this->db->fieldExists( $table, $field, __METHOD__ ) ) {
 720                         $this->output( "...$field field does not exist in $table table, skipping modify field patch.\n" );
 721                 } elseif( $this->updateRowExists( $updateKey ) ) {
 722                         $this->output( "...$field in table $table already modified by patch $patch.\n" );
 723                 } else {
 724                         return $this->applyPatch( $patch, $fullpath, "Modifying $field field of table $table" );
 725                         $this->insertUpdateRow( $updateKey );
 726                 }
 727                 return true;
 728         }
 729
 730         /**
 731          * Purge the objectcache table
 732          */
 733         public function purgeCache() {
 734                 global $wgLocalisationCacheConf;
 735                 # We can't guarantee that the user will be able to use TRUNCATE,
 736                 # but we know that DELETE is available to us
 737                 $this->output( "Purging caches..." );
 738                 $this->db->delete( 'objectcache', '*', __METHOD__ );
 739                 if ( $wgLocalisationCacheConf['manualRecache'] ) {
 740                         $this->rebuildLocalisationCache();
 741                 }
 742                 $this->output( "done.\n" );
 743         }
 744
 745         /**
 746          * Check the site_stats table is not properly populated.
 747          */
 748         protected function checkStats() {
 749                 $this->output( "...site_stats is populated..." );
 750                 $row = $this->db->selectRow( 'site_stats', '*', array( 'ss_row_id' => 1 ), __METHOD__ );
 751                 if ( $row === false ) {
 752                         $this->output( "data is missing! rebuilding...\n" );
 753                 } elseif ( isset( $row->site_stats ) && $row->ss_total_pages == -1 ) {
 754                         $this->output( "missing ss_total_pages, rebuilding...\n" );
 755                 } else {
 756                         $this->output( "done.\n" );
 757                         return;
 758                 }
 759                 SiteStatsInit::doAllAndCommit( $this->db );
 760         }
 761
 762         # Common updater functions
 763
 764         /**
 765          * Sets the number of active users in the site_stats table
 766          */
 767         protected function doActiveUsersInit() {
 768                 $activeUsers = $this->db->selectField( 'site_stats', 'ss_active_users', false, __METHOD__ );
 769                 if ( $activeUsers == -1 ) {
 770                         $activeUsers = $this->db->selectField( 'recentchanges',
 771                                 'COUNT( DISTINCT rc_user_text )',
 772                                 array( 'rc_user != 0', 'rc_bot' => 0, "rc_log_type != 'newusers'" ), __METHOD__
 773                         );
 774                         $this->db->update( 'site_stats',
 775                                 array( 'ss_active_users' => intval( $activeUsers ) ),
 776                                 array( 'ss_row_id' => 1 ), __METHOD__, array( 'LIMIT' => 1 )
 777                         );
 778                 }
 779                 $this->output( "...ss_active_users user count set...\n" );
 780         }
 781
 782         /**
 783          * Populates the log_user_text field in the logging table
 784          */
 785         protected function doLogUsertextPopulation() {
 786                 if ( !$this->updateRowExists( 'populate log_usertext' ) ) {
 787                         $this->output(
 788                         "Populating log_user_text field, printing progress markers. For large\n" .
 789                         "databases, you may want to hit Ctrl-C and do this manually with\n" .
 790                         "maintenance/populateLogUsertext.php.\n" );
 791
 792                         $task = $this->maintenance->runChild( 'PopulateLogUsertext' );
 793                         $task->execute();
 794                         $this->output( "done.\n" );
 795                 }
 796         }
 797
 798         /**
 799          * Migrate log params to new table and index for searching
 800          */
 801         protected function doLogSearchPopulation() {
 802                 if ( !$this->updateRowExists( 'populate log_search' ) ) {
 803                         $this->output(
 804                                 "Populating log_search table, printing progress markers. For large\n" .
 805                                 "databases, you may want to hit Ctrl-C and do this manually with\n" .
 806                                 "maintenance/populateLogSearch.php.\n" );
 807
 808                         $task = $this->maintenance->runChild( 'PopulateLogSearch' );
 809                         $task->execute();
 810                         $this->output( "done.\n" );
 811                 }
 812         }
 813
 814         /**
 815          * Updates the timestamps in the transcache table
 816          */
 817         protected function doUpdateTranscacheField() {
 818                 if ( $this->updateRowExists( 'convert transcache field' ) ) {
 819                         $this->output( "...transcache tc_time already converted.\n" );
 820                         return;
 821                 }
 822
 823                 return $this->applyPatch( 'patch-tc-timestamp.sql', false,
 824                         "Converting tc_time from UNIX epoch to MediaWiki timestamp" );
 825         }
 826
 827         /**
 828          * Update CategoryLinks collation
 829          */
 830         protected function doCollationUpdate() {
 831                 global $wgCategoryCollation;
 832                 if ( $this->db->fieldExists( 'categorylinks', 'cl_collation', __METHOD__ ) ) {
 833                         if ( $this->db->selectField(
 834                                 'categorylinks',
 835                                 'COUNT(*)',
 836                                 'cl_collation != ' . $this->db->addQuotes( $wgCategoryCollation ),
 837                                 __METHOD__
 838                                 ) == 0 ) {
 839                                         $this->output( "...collations up-to-date.\n" );
 840                                         return;
 841                         }
 842
 843                         $this->output( "Updating category collations..." );
 844                         $task = $this->maintenance->runChild( 'UpdateCollation' );
 845                         $task->execute();
 846                         $this->output( "...done.\n" );
 847                 }
 848         }
 849
 850         /**
 851          * Migrates user options from the user table blob to user_properties
 852          */
 853         protected function doMigrateUserOptions() {
 854                 if( $this->db->tableExists( 'user_properties' ) ) {
 855                         $cl = $this->maintenance->runChild( 'ConvertUserOptions', 'convertUserOptions.php' );
 856                         $cl->execute();
 857                         $this->output( "done.\n" );
 858                 }
 859         }
 860
 861         /**
 862          * Rebuilds the localisation cache
 863          */
 864         protected function rebuildLocalisationCache() {
 865                 /**
 866                  * @var $cl RebuildLocalisationCache
 867                  */
 868                 $cl = $this->maintenance->runChild( 'RebuildLocalisationCache', 'rebuildLocalisationCache.php' );
 869                 $this->output( "Rebuilding localisation cache...\n" );
 870                 $cl->setForce();
 871                 $cl->execute();
 872                 $this->output( "done.\n" );
 873         }
 874 }