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+<?php
+/**
+ * Base code for update jobs that put some secondary data extracted
+ * from article content into the database.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Abstract base class for update jobs that put some secondary data extracted
+ * from article content into the database.
+ *
+ * @note: subclasses should NOT start or commit transactions in their doUpdate() method,
+ * a transaction will automatically be wrapped around the update. Starting another
+ * one would break the outer transaction bracket. If need be, subclasses can override
+ * the beginTransaction() and commitTransaction() methods.
+ */
+abstract class SqlDataUpdate extends DataUpdate {
+
+ protected $mDb; //!< Database connection reference
+ protected $mOptions; //!< SELECT options to be used (array)
+
+ private $mHasTransaction; //!< bool whether a transaction is open on this object (internal use only!)
+ protected $mUseTransaction; //!< bool whether this update should be wrapped in a transaction
+
+ /**
+ * Constructor
+ *
+ * @param bool $withTransaction whether this update should be wrapped in a transaction (default: true).
+ * A transaction is only started if no transaction is already in progress,
+ * see beginTransaction() for details.
+ **/
+ public function __construct( $withTransaction = true ) {
+ global $wgAntiLockFlags;
+
+ parent::__construct( );
+
+ if ( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) {
+ $this->mOptions = array();
+ } else {
+ $this->mOptions = array( 'FOR UPDATE' );
+ }
+
+ // @todo: get connection only when it's needed? make sure that doesn't break anything, especially transactions!
+ $this->mDb = wfGetDB( DB_MASTER );
+
+ $this->mWithTransaction = $withTransaction;
+ $this->mHasTransaction = false;
+ }
+
+ /**
+ * Begin a database transaction, if $withTransaction was given as true in the constructor for this SqlDataUpdate.
+ *
+ * Because nested transactions are not supported by the Database class, this implementation
+ * checks Database::trxLevel() and only opens a transaction if none is already active.
+ */
+ public function beginTransaction() {
+ if ( !$this->mWithTransaction ) {
+ return;
+ }
+
+ // NOTE: nested transactions are not supported, only start a transaction if none is open
+ if ( $this->mDb->trxLevel() === 0 ) {
+ $this->mDb->begin( get_class( $this ) . '::beginTransaction' );
+ $this->mHasTransaction = true;
+ }
+ }
+
+ /**
+ * Commit the database transaction started via beginTransaction (if any).
+ */
+ public function commitTransaction() {
+ if ( $this->mHasTransaction ) {
+ $this->mDb->commit( get_class( $this ) . '::commitTransaction' );
+ $this->mHasTransaction = false;
+ }
+ }
+
+ /**
+ * Abort the database transaction started via beginTransaction (if any).
+ */
+ public function abortTransaction() {
+ if ( $this->mHasTransaction ) {
+ $this->mDb->rollback( get_class( $this ) . '::abortTransaction' );
+ $this->mHasTransaction = false;
+ }
+ }
+
+ /**
+ * Invalidate the cache of a list of pages from a single namespace.
+ * This is intended for use by subclasses.
+ *
+ * @param $namespace Integer
+ * @param $dbkeys Array
+ */
+ protected function invalidatePages( $namespace, Array $dbkeys ) {
+ if ( !count( $dbkeys ) ) {
+ return;
+ }
+
+ /**
+ * Determine which pages need to be updated
+ * This is necessary to prevent the job queue from smashing the DB with
+ * large numbers of concurrent invalidations of the same page
+ */
+ $now = $this->mDb->timestamp();
+ $ids = array();
+ $res = $this->mDb->select( 'page', array( 'page_id' ),
+ array(
+ 'page_namespace' => $namespace,
+ 'page_title' => $dbkeys,
+ 'page_touched < ' . $this->mDb->addQuotes( $now )
+ ), __METHOD__
+ );
+ foreach ( $res as $row ) {
+ $ids[] = $row->page_id;
+ }
+ if ( !count( $ids ) ) {
+ return;
+ }
+
+ /**
+ * Do the update
+ * We still need the page_touched condition, in case the row has changed since
+ * the non-locking select above.
+ */
+ $this->mDb->update( 'page', array( 'page_touched' => $now ),
+ array(
+ 'page_id' => $ids,
+ 'page_touched < ' . $this->mDb->addQuotes( $now )
+ ), __METHOD__
+ );
+ }
+
+}