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 resource
  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          * Hold the value of $wgContentHandlerUseDB during the upgrade.
  93          */
  94         protected $holdContentHandlerUseDB = true;
  95
  96         /**
  97          * Constructor
  98          *
  99          * @param DatabaseBase $db To perform updates on
 100          * @param bool $shared Whether to perform updates on shared tables
 101          * @param Maintenance $maintenance Maintenance object which created us
 102          */
 103         protected function __construct( DatabaseBase &$db, $shared, Maintenance $maintenance = null ) {
 104                 $this->db = $db;
 105                 $this->db->setFlag( DBO_DDLMODE ); // For Oracle's handling of schema files
 106                 $this->shared = $shared;
 107                 if ( $maintenance ) {
 108                         $this->maintenance = $maintenance;
 109                         $this->fileHandle = $maintenance->fileHandle;
 110                 } else {
 111                         $this->maintenance = new FakeMaintenance;
 112                 }
 113                 $this->maintenance->setDB( $db );
 114                 $this->initOldGlobals();
 115                 $this->loadExtensions();
 116                 wfRunHooks( 'LoadExtensionSchemaUpdates', array( $this ) );
 117         }
 118
 119         /**
 120          * Initialize all of the old globals. One day this should all become
 121          * something much nicer
 122          */
 123         private function initOldGlobals() {
 124                 global $wgExtNewTables, $wgExtNewFields, $wgExtPGNewFields,
 125                         $wgExtPGAlteredFields, $wgExtNewIndexes, $wgExtModifiedFields;
 126
 127                 # For extensions only, should be populated via hooks
 128                 # $wgDBtype should be checked to specifiy the proper file
 129                 $wgExtNewTables = array(); // table, dir
 130                 $wgExtNewFields = array(); // table, column, dir
 131                 $wgExtPGNewFields = array(); // table, column, column attributes; for PostgreSQL
 132                 $wgExtPGAlteredFields = array(); // table, column, new type, conversion method; for PostgreSQL
 133                 $wgExtNewIndexes = array(); // table, index, dir
 134                 $wgExtModifiedFields = array(); // table, index, dir
 135         }
 136
 137         /**
 138          * Loads LocalSettings.php, if needed, and initialises everything needed for
 139          * LoadExtensionSchemaUpdates hook.
 140          */
 141         private function loadExtensions() {
 142                 if ( !defined( 'MEDIAWIKI_INSTALL' ) ) {
 143                         return; // already loaded
 144                 }
 145                 $vars = Installer::getExistingLocalSettings();
 146                 if ( !$vars ) {
 147                         return; // no LocalSettings found
 148                 }
 149                 if ( !isset( $vars['wgHooks'] ) || !isset( $vars['wgHooks']['LoadExtensionSchemaUpdates'] ) ) {
 150                         return;
 151                 }
 152                 global $wgHooks, $wgAutoloadClasses;
 153                 $wgHooks['LoadExtensionSchemaUpdates'] = $vars['wgHooks']['LoadExtensionSchemaUpdates'];
 154                 $wgAutoloadClasses = $wgAutoloadClasses + $vars['wgAutoloadClasses'];
 155         }
 156
 157         /**
 158          * @param DatabaseBase $db
 159          * @param bool $shared
 160          * @param Maintenance $maintenance
 161          *
 162          * @throws MWException
 163          * @return DatabaseUpdater
 164          */
 165         public static function newForDB( &$db, $shared = false, $maintenance = null ) {
 166                 $type = $db->getType();
 167                 if ( in_array( $type, Installer::getDBTypes() ) ) {
 168                         $class = ucfirst( $type ) . 'Updater';
 169
 170                         return new $class( $db, $shared, $maintenance );
 171                 } else {
 172                         throw new MWException( __METHOD__ . ' called for unsupported $wgDBtype' );
 173                 }
 174         }
 175
 176         /**
 177          * Get a database connection to run updates
 178          *
 179          * @return DatabaseBase
 180          */
 181         public function getDB() {
 182                 return $this->db;
 183         }
 184
 185         /**
 186          * Output some text. If we're running from web, escape the text first.
 187          *
 188          * @param string $str Text to output
 189          */
 190         public function output( $str ) {
 191                 if ( $this->maintenance->isQuiet() ) {
 192                         return;
 193                 }
 194                 global $wgCommandLineMode;
 195                 if ( !$wgCommandLineMode ) {
 196                         $str = htmlspecialchars( $str );
 197                 }
 198                 echo $str;
 199                 flush();
 200         }
 201
 202         /**
 203          * Add a new update coming from an extension. This should be called by
 204          * extensions while executing the LoadExtensionSchemaUpdates hook.
 205          *
 206          * @since 1.17
 207          *
 208          * @param array $update The update to run. Format is the following:
 209          *                first item is the callback function, it also can be a
 210          *                simple string with the name of a function in this class,
 211          *                following elements are parameters to the function.
 212          *                Note that callback functions will receive this object as
 213          *                first parameter.
 214          */
 215         public function addExtensionUpdate( array $update ) {
 216                 $this->extensionUpdates[] = $update;
 217         }
 218
 219         /**
 220          * Convenience wrapper for addExtensionUpdate() when adding a new table (which
 221          * is the most common usage of updaters in an extension)
 222          *
 223          * @since 1.18
 224          *
 225          * @param string $tableName Name of table to create
 226          * @param string $sqlPath Full path to the schema file
 227          */
 228         public function addExtensionTable( $tableName, $sqlPath ) {
 229                 $this->extensionUpdates[] = array( 'addTable', $tableName, $sqlPath, true );
 230         }
 231
 232         /**
 233          * @since 1.19
 234          *
 235          * @param string $tableName
 236          * @param string $indexName
 237          * @param string $sqlPath
 238          */
 239         public function addExtensionIndex( $tableName, $indexName, $sqlPath ) {
 240                 $this->extensionUpdates[] = array( 'addIndex', $tableName, $indexName, $sqlPath, true );
 241         }
 242
 243         /**
 244          *
 245          * @since 1.19
 246          *
 247          * @param string $tableName
 248          * @param string $columnName
 249          * @param string $sqlPath
 250          */
 251         public function addExtensionField( $tableName, $columnName, $sqlPath ) {
 252                 $this->extensionUpdates[] = array( 'addField', $tableName, $columnName, $sqlPath, true );
 253         }
 254
 255         /**
 256          *
 257          * @since 1.20
 258          *
 259          * @param string $tableName
 260          * @param string $columnName
 261          * @param string $sqlPath
 262          */
 263         public function dropExtensionField( $tableName, $columnName, $sqlPath ) {
 264                 $this->extensionUpdates[] = array( 'dropField', $tableName, $columnName, $sqlPath, true );
 265         }
 266
 267         /**
 268          * Drop an index from an extension table
 269          *
 270          * @since 1.21
 271          *
 272          * @param string $tableName The table name
 273          * @param string $indexName The index name
 274          * @param string $sqlPath The path to the SQL change path
 275          */
 276         public function dropExtensionIndex( $tableName, $indexName, $sqlPath ) {
 277                 $this->extensionUpdates[] = array( 'dropIndex', $tableName, $indexName, $sqlPath, true );
 278         }
 279
 280         /**
 281          *
 282          * @since 1.20
 283          *
 284          * @param string $tableName
 285          * @param string $sqlPath
 286          */
 287         public function dropExtensionTable( $tableName, $sqlPath ) {
 288                 $this->extensionUpdates[] = array( 'dropTable', $tableName, $sqlPath, true );
 289         }
 290
 291         /**
 292          * Rename an index on an extension table
 293          *
 294          * @since 1.21
 295          *
 296          * @param string $tableName The table name
 297          * @param string $oldIndexName The old index name
 298          * @param string $newIndexName The new index name
 299          * @param bool $skipBothIndexExistWarning Whether to warn if both the old
 300          * and the new indexes exist. [facultative; by default, false]
 301          * @param string $sqlPath The path to the SQL change path
 302          */
 303         public function renameExtensionIndex( $tableName, $oldIndexName, $newIndexName,
 304                 $sqlPath, $skipBothIndexExistWarning = false
 305         ) {
 306                 $this->extensionUpdates[] = array(
 307                         'renameIndex',
 308                         $tableName,
 309                         $oldIndexName,
 310                         $newIndexName,
 311                         $skipBothIndexExistWarning,
 312                         $sqlPath,
 313                         true
 314                 );
 315         }
 316
 317         /**
 318          * @since 1.21
 319          *
 320          * @param string $tableName The table name
 321          * @param string $fieldName The field to be modified
 322          * @param string $sqlPath The path to the SQL change path
 323          */
 324         public function modifyExtensionField( $tableName, $fieldName, $sqlPath ) {
 325                 $this->extensionUpdates[] = array( 'modifyField', $tableName, $fieldName, $sqlPath, true );
 326         }
 327
 328         /**
 329          *
 330          * @since 1.20
 331          *
 332          * @param string $tableName
 333          * @return bool
 334          */
 335         public function tableExists( $tableName ) {
 336                 return ( $this->db->tableExists( $tableName, __METHOD__ ) );
 337         }
 338
 339         /**
 340          * Add a maintenance script to be run after the database updates are complete.
 341          *
 342          * Script should subclass LoggedUpdateMaintenance
 343          *
 344          * @since 1.19
 345          *
 346          * @param string $class Name of a Maintenance subclass
 347          */
 348         public function addPostDatabaseUpdateMaintenance( $class ) {
 349                 $this->postDatabaseUpdateMaintenance[] = $class;
 350         }
 351
 352         /**
 353          * Get the list of extension-defined updates
 354          *
 355          * @return array
 356          */
 357         protected function getExtensionUpdates() {
 358                 return $this->extensionUpdates;
 359         }
 360
 361         /**
 362          * @since 1.17
 363          *
 364          * @return array
 365          */
 366         public function getPostDatabaseUpdateMaintenance() {
 367                 return $this->postDatabaseUpdateMaintenance;
 368         }
 369
 370         /**
 371          * @since 1.21
 372          *
 373          * Writes the schema updates desired to a file for the DB Admin to run.
 374          * @param array $schemaUpdate
 375          */
 376         private function writeSchemaUpdateFile( $schemaUpdate = array() ) {
 377                 $updates = $this->updatesSkipped;
 378                 $this->updatesSkipped = array();
 379
 380                 foreach ( $updates as $funcList ) {
 381                         $func = $funcList[0];
 382                         $arg = $funcList[1];
 383                         $origParams = $funcList[2];
 384                         call_user_func_array( $func, $arg );
 385                         flush();
 386                         $this->updatesSkipped[] = $origParams;
 387                 }
 388         }
 389
 390         /**
 391          * Do all the updates
 392          *
 393          * @param array $what What updates to perform
 394          */
 395         public function doUpdates( $what = array( 'core', 'extensions', 'stats' ) ) {
 396                 global $wgVersion;
 397
 398                 $this->db->begin( __METHOD__ );
 399                 $what = array_flip( $what );
 400                 $this->skipSchema = isset( $what['noschema'] ) || $this->fileHandle !== null;
 401                 if ( isset( $what['core'] ) ) {
 402                         $this->runUpdates( $this->getCoreUpdateList(), false );
 403                 }
 404                 if ( isset( $what['extensions'] ) ) {
 405                         $this->runUpdates( $this->getOldGlobalUpdates(), false );
 406                         $this->runUpdates( $this->getExtensionUpdates(), true );
 407                 }
 408
 409                 if ( isset( $what['stats'] ) ) {
 410                         $this->checkStats();
 411                 }
 412
 413                 $this->setAppliedUpdates( $wgVersion, $this->updates );
 414
 415                 if ( $this->fileHandle ) {
 416                         $this->skipSchema = false;
 417                         $this->writeSchemaUpdateFile();
 418                         $this->setAppliedUpdates( "$wgVersion-schema", $this->updatesSkipped );
 419                 }
 420
 421                 $this->db->commit( __METHOD__ );
 422         }
 423
 424         /**
 425          * Helper function for doUpdates()
 426          *
 427          * @param array $updates Array of updates to run
 428          * @param bool $passSelf Whether to pass this object we calling external functions
 429          */
 430         private function runUpdates( array $updates, $passSelf ) {
 431                 $updatesDone = array();
 432                 $updatesSkipped = array();
 433                 foreach ( $updates as $params ) {
 434                         $origParams = $params;
 435                         $func = array_shift( $params );
 436                         if ( !is_array( $func ) && method_exists( $this, $func ) ) {
 437                                 $func = array( $this, $func );
 438                         } elseif ( $passSelf ) {
 439                                 array_unshift( $params, $this );
 440                         }
 441                         $ret = call_user_func_array( $func, $params );
 442                         flush();
 443                         if ( $ret !== false ) {
 444                                 $updatesDone[] = $origParams;
 445                         } else {
 446                                 $updatesSkipped[] = array( $func, $params, $origParams );
 447                         }
 448                 }
 449                 $this->updatesSkipped = array_merge( $this->updatesSkipped, $updatesSkipped );
 450                 $this->updates = array_merge( $this->updates, $updatesDone );
 451         }
 452
 453         /**
 454          * @param string $version
 455          * @param array $updates
 456          */
 457         protected function setAppliedUpdates( $version, $updates = array() ) {
 458                 $this->db->clearFlag( DBO_DDLMODE );
 459                 if ( !$this->canUseNewUpdatelog() ) {
 460                         return;
 461                 }
 462                 $key = "updatelist-$version-" . time();
 463                 $this->db->insert( 'updatelog',
 464                         array( 'ul_key' => $key, 'ul_value' => serialize( $updates ) ),
 465                         __METHOD__ );
 466                 $this->db->setFlag( DBO_DDLMODE );
 467         }
 468
 469         /**
 470          * Helper function: check if the given key is present in the updatelog table.
 471          * Obviously, only use this for updates that occur after the updatelog table was
 472          * created!
 473          * @param string $key Name of the key to check for
 474          * @return bool
 475          */
 476         public function updateRowExists( $key ) {
 477                 $row = $this->db->selectRow(
 478                         'updatelog',
 479                         # Bug 65813
 480                         '1 AS X',
 481                         array( 'ul_key' => $key ),
 482                         __METHOD__
 483                 );
 484
 485                 return (bool)$row;
 486         }
 487
 488         /**
 489          * Helper function: Add a key to the updatelog table
 490          * Obviously, only use this for updates that occur after the updatelog table was
 491          * created!
 492          * @param string $key Name of key to insert
 493          * @param string $val [optional] Value to insert along with the key
 494          */
 495         public function insertUpdateRow( $key, $val = null ) {
 496                 $this->db->clearFlag( DBO_DDLMODE );
 497                 $values = array( 'ul_key' => $key );
 498                 if ( $val && $this->canUseNewUpdatelog() ) {
 499                         $values['ul_value'] = $val;
 500                 }
 501                 $this->db->insert( 'updatelog', $values, __METHOD__, 'IGNORE' );
 502                 $this->db->setFlag( DBO_DDLMODE );
 503         }
 504
 505         /**
 506          * Updatelog was changed in 1.17 to have a ul_value column so we can record
 507          * more information about what kind of updates we've done (that's what this
 508          * class does). Pre-1.17 wikis won't have this column, and really old wikis
 509          * might not even have updatelog at all
 510          *
 511          * @return bool
 512          */
 513         protected function canUseNewUpdatelog() {
 514                 return $this->db->tableExists( 'updatelog', __METHOD__ ) &&
 515                         $this->db->fieldExists( 'updatelog', 'ul_value', __METHOD__ );
 516         }
 517
 518         /**
 519          * Returns whether updates should be executed on the database table $name.
 520          * Updates will be prevented if the table is a shared table and it is not
 521          * specified to run updates on shared tables.
 522          *
 523          * @param string $name Table name
 524          * @return bool
 525          */
 526         protected function doTable( $name ) {
 527                 global $wgSharedDB, $wgSharedTables;
 528
 529                 // Don't bother to check $wgSharedTables if there isn't a shared database
 530                 // or the user actually also wants to do updates on the shared database.
 531                 if ( $wgSharedDB === null || $this->shared ) {
 532                         return true;
 533                 }
 534
 535                 if ( in_array( $name, $wgSharedTables ) ) {
 536                         $this->output( "...skipping update to shared table $name.\n" );
 537                         return false;
 538                 } else {
 539                         return true;
 540                 }
 541         }
 542
 543         /**
 544          * Before 1.17, we used to handle updates via stuff like
 545          * $wgExtNewTables/Fields/Indexes. This is nasty :) We refactored a lot
 546          * of this in 1.17 but we want to remain back-compatible for a while. So
 547          * load up these old global-based things into our update list.
 548          *
 549          * @return array
 550          */
 551         protected function getOldGlobalUpdates() {
 552                 global $wgExtNewFields, $wgExtNewTables, $wgExtModifiedFields,
 553                         $wgExtNewIndexes;
 554
 555                 $updates = array();
 556
 557                 foreach ( $wgExtNewTables as $tableRecord ) {
 558                         $updates[] = array(
 559                                 'addTable', $tableRecord[0], $tableRecord[1], true
 560                         );
 561                 }
 562
 563                 foreach ( $wgExtNewFields as $fieldRecord ) {
 564                         $updates[] = array(
 565                                 'addField', $fieldRecord[0], $fieldRecord[1],
 566                                 $fieldRecord[2], true
 567                         );
 568                 }
 569
 570                 foreach ( $wgExtNewIndexes as $fieldRecord ) {
 571                         $updates[] = array(
 572                                 'addIndex', $fieldRecord[0], $fieldRecord[1],
 573                                 $fieldRecord[2], true
 574                         );
 575                 }
 576
 577                 foreach ( $wgExtModifiedFields as $fieldRecord ) {
 578                         $updates[] = array(
 579                                 'modifyField', $fieldRecord[0], $fieldRecord[1],
 580                                 $fieldRecord[2], true
 581                         );
 582                 }
 583
 584                 return $updates;
 585         }
 586
 587         /**
 588          * Get an array of updates to perform on the database. Should return a
 589          * multi-dimensional array. The main key is the MediaWiki version (1.12,
 590          * 1.13...) with the values being arrays of updates, identical to how
 591          * updaters.inc did it (for now)
 592          *
 593          * @return array
 594          */
 595         abstract protected function getCoreUpdateList();
 596
 597         /**
 598          * Append an SQL fragment to the open file handle.
 599          *
 600          * @param string $filename File name to open
 601          */
 602         public function copyFile( $filename ) {
 603                 $this->db->sourceFile( $filename, false, false, false,
 604                         array( $this, 'appendLine' )
 605                 );
 606         }
 607
 608         /**
 609          * Append a line to the open filehandle.  The line is assumed to
 610          * be a complete SQL statement.
 611          *
 612          * This is used as a callback for for sourceLine().
 613          *
 614          * @param string $line Text to append to the file
 615          * @return bool False to skip actually executing the file
 616          * @throws MWException
 617          */
 618         public function appendLine( $line ) {
 619                 $line = rtrim( $line ) . ";\n";
 620                 if ( fwrite( $this->fileHandle, $line ) === false ) {
 621                         throw new MWException( "trouble writing file" );
 622                 }
 623
 624                 return false;
 625         }
 626
 627         /**
 628          * Applies a SQL patch
 629          *
 630          * @param string $path Path to the patch file
 631          * @param bool $isFullPath Whether to treat $path as a relative or not
 632          * @param string $msg Description of the patch
 633          * @return bool False if patch is skipped.
 634          */
 635         protected function applyPatch( $path, $isFullPath = false, $msg = null ) {
 636                 if ( $msg === null ) {
 637                         $msg = "Applying $path patch";
 638                 }
 639                 if ( $this->skipSchema ) {
 640                         $this->output( "...skipping schema change ($msg).\n" );
 641
 642                         return false;
 643                 }
 644
 645                 $this->output( "$msg ..." );
 646
 647                 if ( !$isFullPath ) {
 648                         $path = $this->db->patchPath( $path );
 649                 }
 650                 if ( $this->fileHandle !== null ) {
 651                         $this->copyFile( $path );
 652                 } else {
 653                         $this->db->sourceFile( $path );
 654                 }
 655                 $this->output( "done.\n" );
 656
 657                 return true;
 658         }
 659
 660         /**
 661          * Add a new table to the database
 662          *
 663          * @param string $name Name of the new table
 664          * @param string $patch Path to the patch file
 665          * @param bool $fullpath Whether to treat $patch path as a relative or not
 666          * @return bool False if this was skipped because schema changes are skipped
 667          */
 668         protected function addTable( $name, $patch, $fullpath = false ) {
 669                 if ( !$this->doTable( $name ) ) {
 670                         return true;
 671                 }
 672
 673                 if ( $this->db->tableExists( $name, __METHOD__ ) ) {
 674                         $this->output( "...$name table already exists.\n" );
 675                 } else {
 676                         return $this->applyPatch( $patch, $fullpath, "Creating $name table" );
 677                 }
 678
 679                 return true;
 680         }
 681
 682         /**
 683          * Add a new field to an existing table
 684          *
 685          * @param string $table Name of the table to modify
 686          * @param string $field Name of the new field
 687          * @param string $patch Path to the patch file
 688          * @param bool $fullpath Whether to treat $patch path as a relative or not
 689          * @return bool False if this was skipped because schema changes are skipped
 690          */
 691         protected function addField( $table, $field, $patch, $fullpath = false ) {
 692                 if ( !$this->doTable( $table ) ) {
 693                         return true;
 694                 }
 695
 696                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 697                         $this->output( "...$table table does not exist, skipping new field patch.\n" );
 698                 } elseif ( $this->db->fieldExists( $table, $field, __METHOD__ ) ) {
 699                         $this->output( "...have $field field in $table table.\n" );
 700                 } else {
 701                         return $this->applyPatch( $patch, $fullpath, "Adding $field field to table $table" );
 702                 }
 703
 704                 return true;
 705         }
 706
 707         /**
 708          * Add a new index to an existing table
 709          *
 710          * @param string $table Name of the table to modify
 711          * @param string $index Name of the new index
 712          * @param string $patch Path to the patch file
 713          * @param bool $fullpath Whether to treat $patch path as a relative or not
 714          * @return bool False if this was skipped because schema changes are skipped
 715          */
 716         protected function addIndex( $table, $index, $patch, $fullpath = false ) {
 717                 if ( !$this->doTable( $table ) ) {
 718                         return true;
 719                 }
 720
 721                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 722                         $this->output( "...skipping: '$table' table doesn't exist yet.\n" );
 723                 } elseif ( $this->db->indexExists( $table, $index, __METHOD__ ) ) {
 724                         $this->output( "...index $index already set on $table table.\n" );
 725                 } else {
 726                         return $this->applyPatch( $patch, $fullpath, "Adding index $index to table $table" );
 727                 }
 728
 729                 return true;
 730         }
 731
 732         /**
 733          * Drop a field from an existing table
 734          *
 735          * @param string $table Name of the table to modify
 736          * @param string $field Name of the old field
 737          * @param string $patch Path to the patch file
 738          * @param bool $fullpath Whether to treat $patch path as a relative or not
 739          * @return bool False if this was skipped because schema changes are skipped
 740          */
 741         protected function dropField( $table, $field, $patch, $fullpath = false ) {
 742                 if ( !$this->doTable( $table ) ) {
 743                         return true;
 744                 }
 745
 746                 if ( $this->db->fieldExists( $table, $field, __METHOD__ ) ) {
 747                         return $this->applyPatch( $patch, $fullpath, "Table $table contains $field field. Dropping" );
 748                 } else {
 749                         $this->output( "...$table table does not contain $field field.\n" );
 750                 }
 751
 752                 return true;
 753         }
 754
 755         /**
 756          * Drop an index from an existing table
 757          *
 758          * @param string $table Name of the table to modify
 759          * @param string $index Name of the index
 760          * @param string $patch Path to the patch file
 761          * @param bool $fullpath Whether to treat $patch path as a relative or not
 762          * @return bool False if this was skipped because schema changes are skipped
 763          */
 764         protected function dropIndex( $table, $index, $patch, $fullpath = false ) {
 765                 if ( !$this->doTable( $table ) ) {
 766                         return true;
 767                 }
 768
 769                 if ( $this->db->indexExists( $table, $index, __METHOD__ ) ) {
 770                         return $this->applyPatch( $patch, $fullpath, "Dropping $index index from table $table" );
 771                 } else {
 772                         $this->output( "...$index key doesn't exist.\n" );
 773                 }
 774
 775                 return true;
 776         }
 777
 778         /**
 779          * Rename an index from an existing table
 780          *
 781          * @param string $table Name of the table to modify
 782          * @param string $oldIndex Old name of the index
 783          * @param string $newIndex New name of the index
 784          * @param bool $skipBothIndexExistWarning Whether to warn if both the
 785          * old and the new indexes exist.
 786          * @param string $patch Path to the patch file
 787          * @param bool $fullpath Whether to treat $patch path as a relative or not
 788          * @return bool False if this was skipped because schema changes are skipped
 789          */
 790         protected function renameIndex( $table, $oldIndex, $newIndex,
 791                 $skipBothIndexExistWarning, $patch, $fullpath = false
 792         ) {
 793                 if ( !$this->doTable( $table ) ) {
 794                         return true;
 795                 }
 796
 797                 // First requirement: the table must exist
 798                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 799                         $this->output( "...skipping: '$table' table doesn't exist yet.\n" );
 800
 801                         return true;
 802                 }
 803
 804                 // Second requirement: the new index must be missing
 805                 if ( $this->db->indexExists( $table, $newIndex, __METHOD__ ) ) {
 806                         $this->output( "...index $newIndex already set on $table table.\n" );
 807                         if ( !$skipBothIndexExistWarning &&
 808                                 $this->db->indexExists( $table, $oldIndex, __METHOD__ )
 809                         ) {
 810                                 $this->output( "...WARNING: $oldIndex still exists, despite it has " .
 811                                         "been renamed into $newIndex (which also exists).\n" .
 812                                         "            $oldIndex should be manually removed if not needed anymore.\n" );
 813                         }
 814
 815                         return true;
 816                 }
 817
 818                 // Third requirement: the old index must exist
 819                 if ( !$this->db->indexExists( $table, $oldIndex, __METHOD__ ) ) {
 820                         $this->output( "...skipping: index $oldIndex doesn't exist.\n" );
 821
 822                         return true;
 823                 }
 824
 825                 // Requirements have been satisfied, patch can be applied
 826                 return $this->applyPatch(
 827                         $patch,
 828                         $fullpath,
 829                         "Renaming index $oldIndex into $newIndex to table $table"
 830                 );
 831         }
 832
 833         /**
 834          * If the specified table exists, drop it, or execute the
 835          * patch if one is provided.
 836          *
 837          * Public @since 1.20
 838          *
 839          * @param string $table Table to drop.
 840          * @param string|bool $patch String of patch file that will drop the table. Default: false.
 841          * @param bool $fullpath Whether $patch is a full path. Default: false.
 842          * @return bool False if this was skipped because schema changes are skipped
 843          */
 844         public function dropTable( $table, $patch = false, $fullpath = false ) {
 845                 if ( !$this->doTable( $table ) ) {
 846                         return true;
 847                 }
 848
 849                 if ( $this->db->tableExists( $table, __METHOD__ ) ) {
 850                         $msg = "Dropping table $table";
 851
 852                         if ( $patch === false ) {
 853                                 $this->output( "$msg ..." );
 854                                 $this->db->dropTable( $table, __METHOD__ );
 855                                 $this->output( "done.\n" );
 856                         } else {
 857                                 return $this->applyPatch( $patch, $fullpath, $msg );
 858                         }
 859                 } else {
 860                         $this->output( "...$table doesn't exist.\n" );
 861                 }
 862
 863                 return true;
 864         }
 865
 866         /**
 867          * Modify an existing field
 868          *
 869          * @param string $table Name of the table to which the field belongs
 870          * @param string $field Name of the field to modify
 871          * @param string $patch Path to the patch file
 872          * @param bool $fullpath Whether to treat $patch path as a relative or not
 873          * @return bool False if this was skipped because schema changes are skipped
 874          */
 875         public function modifyField( $table, $field, $patch, $fullpath = false ) {
 876                 if ( !$this->doTable( $table ) ) {
 877                         return true;
 878                 }
 879
 880                 $updateKey = "$table-$field-$patch";
 881                 if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
 882                         $this->output( "...$table table does not exist, skipping modify field patch.\n" );
 883                 } elseif ( !$this->db->fieldExists( $table, $field, __METHOD__ ) ) {
 884                         $this->output( "...$field field does not exist in $table table, " .
 885                                 "skipping modify field patch.\n" );
 886                 } elseif ( $this->updateRowExists( $updateKey ) ) {
 887                         $this->output( "...$field in table $table already modified by patch $patch.\n" );
 888                 } else {
 889                         $this->insertUpdateRow( $updateKey );
 890
 891                         return $this->applyPatch( $patch, $fullpath, "Modifying $field field of table $table" );
 892                 }
 893
 894                 return true;
 895         }
 896
 897         /**
 898          * Purge the objectcache table
 899          */
 900         public function purgeCache() {
 901                 global $wgLocalisationCacheConf;
 902                 # We can't guarantee that the user will be able to use TRUNCATE,
 903                 # but we know that DELETE is available to us
 904                 $this->output( "Purging caches..." );
 905                 $this->db->delete( 'objectcache', '*', __METHOD__ );
 906                 if ( $wgLocalisationCacheConf['manualRecache'] ) {
 907                         $this->rebuildLocalisationCache();
 908                 }
 909                 MessageBlobStore::clear();
 910                 $this->output( "done.\n" );
 911         }
 912
 913         /**
 914          * Check the site_stats table is not properly populated.
 915          */
 916         protected function checkStats() {
 917                 $this->output( "...site_stats is populated..." );
 918                 $row = $this->db->selectRow( 'site_stats', '*', array( 'ss_row_id' => 1 ), __METHOD__ );
 919                 if ( $row === false ) {
 920                         $this->output( "data is missing! rebuilding...\n" );
 921                 } elseif ( isset( $row->site_stats ) && $row->ss_total_pages == -1 ) {
 922                         $this->output( "missing ss_total_pages, rebuilding...\n" );
 923                 } else {
 924                         $this->output( "done.\n" );
 925
 926                         return;
 927                 }
 928                 SiteStatsInit::doAllAndCommit( $this->db );
 929         }
 930
 931         # Common updater functions
 932
 933         /**
 934          * Sets the number of active users in the site_stats table
 935          */
 936         protected function doActiveUsersInit() {
 937                 $activeUsers = $this->db->selectField( 'site_stats', 'ss_active_users', false, __METHOD__ );
 938                 if ( $activeUsers == -1 ) {
 939                         $activeUsers = $this->db->selectField( 'recentchanges',
 940                                 'COUNT( DISTINCT rc_user_text )',
 941                                 array( 'rc_user != 0', 'rc_bot' => 0, "rc_log_type != 'newusers'" ), __METHOD__
 942                         );
 943                         $this->db->update( 'site_stats',
 944                                 array( 'ss_active_users' => intval( $activeUsers ) ),
 945                                 array( 'ss_row_id' => 1 ), __METHOD__, array( 'LIMIT' => 1 )
 946                         );
 947                 }
 948                 $this->output( "...ss_active_users user count set...\n" );
 949         }
 950
 951         /**
 952          * Populates the log_user_text field in the logging table
 953          */
 954         protected function doLogUsertextPopulation() {
 955                 if ( !$this->updateRowExists( 'populate log_usertext' ) ) {
 956                         $this->output(
 957                                 "Populating log_user_text field, printing progress markers. For large\n" .
 958                                 "databases, you may want to hit Ctrl-C and do this manually with\n" .
 959                                 "maintenance/populateLogUsertext.php.\n"
 960                         );
 961
 962                         $task = $this->maintenance->runChild( 'PopulateLogUsertext' );
 963                         $task->execute();
 964                         $this->output( "done.\n" );
 965                 }
 966         }
 967
 968         /**
 969          * Migrate log params to new table and index for searching
 970          */
 971         protected function doLogSearchPopulation() {
 972                 if ( !$this->updateRowExists( 'populate log_search' ) ) {
 973                         $this->output(
 974                                 "Populating log_search table, printing progress markers. For large\n" .
 975                                 "databases, you may want to hit Ctrl-C and do this manually with\n" .
 976                                 "maintenance/populateLogSearch.php.\n" );
 977
 978                         $task = $this->maintenance->runChild( 'PopulateLogSearch' );
 979                         $task->execute();
 980                         $this->output( "done.\n" );
 981                 }
 982         }
 983
 984         /**
 985          * Updates the timestamps in the transcache table
 986          */
 987         protected function doUpdateTranscacheField() {
 988                 if ( $this->updateRowExists( 'convert transcache field' ) ) {
 989                         $this->output( "...transcache tc_time already converted.\n" );
 990
 991                         return true;
 992                 }
 993
 994                 return $this->applyPatch( 'patch-tc-timestamp.sql', false,
 995                         "Converting tc_time from UNIX epoch to MediaWiki timestamp" );
 996         }
 997
 998         /**
 999          * Update CategoryLinks collation
1000          */
1001         protected function doCollationUpdate() {
1002                 global $wgCategoryCollation;
1003                 if ( $this->db->fieldExists( 'categorylinks', 'cl_collation', __METHOD__ ) ) {
1004                         if ( $this->db->selectField(
1005                                 'categorylinks',
1006                                 'COUNT(*)',
1007                                 'cl_collation != ' . $this->db->addQuotes( $wgCategoryCollation ),
1008                                 __METHOD__
1009                                 ) == 0
1010                         ) {
1011                                 $this->output( "...collations up-to-date.\n" );
1012
1013                                 return;
1014                         }
1015
1016                         $this->output( "Updating category collations..." );
1017                         $task = $this->maintenance->runChild( 'UpdateCollation' );
1018                         $task->execute();
1019                         $this->output( "...done.\n" );
1020                 }
1021         }
1022
1023         /**
1024          * Migrates user options from the user table blob to user_properties
1025          */
1026         protected function doMigrateUserOptions() {
1027                 if ( $this->db->tableExists( 'user_properties' ) ) {
1028                         $cl = $this->maintenance->runChild( 'ConvertUserOptions', 'convertUserOptions.php' );
1029                         $cl->execute();
1030                         $this->output( "done.\n" );
1031                 }
1032         }
1033
1034         /**
1035          * Rebuilds the localisation cache
1036          */
1037         protected function rebuildLocalisationCache() {
1038                 /**
1039                  * @var $cl RebuildLocalisationCache
1040                  */
1041                 $cl = $this->maintenance->runChild( 'RebuildLocalisationCache', 'rebuildLocalisationCache.php' );
1042                 $this->output( "Rebuilding localisation cache...\n" );
1043                 $cl->setForce();
1044                 $cl->execute();
1045                 $this->output( "done.\n" );
1046         }
1047
1048         /**
1049          * Turns off content handler fields during parts of the upgrade
1050          * where they aren't available.
1051          */
1052         protected function disableContentHandlerUseDB() {
1053                 global $wgContentHandlerUseDB;
1054
1055                 if ( $wgContentHandlerUseDB ) {
1056                         $this->output( "Turning off Content Handler DB fields for this part of upgrade.\n" );
1057                         $this->holdContentHandlerUseDB = $wgContentHandlerUseDB;
1058                         $wgContentHandlerUseDB = false;
1059                 }
1060         }
1061
1062         /**
1063          * Turns content handler fields back on.
1064          */
1065         protected function enableContentHandlerUseDB() {
1066                 global $wgContentHandlerUseDB;
1067
1068                 if ( $this->holdContentHandlerUseDB ) {
1069                         $this->output( "Content Handler DB fields should be usable now.\n" );
1070                         $wgContentHandlerUseDB = $this->holdContentHandlerUseDB;
1071                 }
1072         }
1073 }