1 files changed, 128 insertions, 0 deletions
diff --git a/www/wiki/includes/utils/BatchRowUpdate.php b/www/wiki/includes/utils/BatchRowUpdate.php
new file mode 100644
index 00000000..f42b5a07
--- /dev/null
+++ b/www/wiki/includes/utils/BatchRowUpdate.php
@@ -0,0 +1,128 @@
+<?php
+/*
+ * Ties together the batch update components to provide a composable
+ * method of batch updating rows in a database. To use create a class
+ * implementing the RowUpdateGenerator interface and configure the
+ * BatchRowIterator and BatchRowWriter for access to the correct table.
+ * The components will handle reading, writing, and waiting for replica DBs
+ * while the generator implementation handles generating update arrays
+ * for singular rows.
+ *
+ * Instantiate:
+ *   $updater = new BatchRowUpdate(
+ *       new BatchRowIterator( $dbr, 'some_table', 'primary_key_column', 500 ),
+ *       new BatchRowWriter( $dbw, 'some_table', 'clusterName' ),
+ *       new MyImplementationOfRowUpdateGenerator
+ *   );
+ *
+ * Run:
+ *   $updater->execute();
+ *
+ * An example maintenance script utilizing the BatchRowUpdate can be
+ * located in the Echo extension file maintenance/updateSchema.php
+ *
+ * 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
+ * @ingroup Maintenance
+ */
+class BatchRowUpdate {
+	/**
+	 * @var BatchRowIterator $reader Iterator that returns an array of
+	 *  database rows
+	 */
+	protected $reader;
+
+	/**
+	 * @var BatchRowWriter $writer Writer capable of pushing row updates
+	 *  to the database
+	 */
+	protected $writer;
+
+	/**
+	 * @var RowUpdateGenerator $generator Generates single row updates
+	 *  based on the rows content
+	 */
+	protected $generator;
+
+	/**
+	 * @var callable $output Output callback
+	 */
+	protected $output;
+
+	/**
+	 * @param BatchRowIterator $reader Iterator that returns an
+	 *  array of database rows
+	 * @param BatchRowWriter $writer Writer capable of pushing
+	 *  row updates to the database
+	 * @param RowUpdateGenerator $generator Generates single row updates
+	 *  based on the rows content
+	 */
+	public function __construct(
+		BatchRowIterator $reader, BatchRowWriter $writer, RowUpdateGenerator $generator
+	) {
+		$this->reader = $reader;
+		$this->writer = $writer;
+		$this->generator = $generator;
+		$this->output = function () {
+		}; // nop
+	}
+
+	/**
+	 * Runs the batch update process
+	 */
+	public function execute() {
+		foreach ( $this->reader as $rows ) {
+			$updates = [];
+			foreach ( $rows as $row ) {
+				$update = $this->generator->update( $row );
+				if ( $update ) {
+					$updates[] = [
+						'primaryKey' => $this->reader->extractPrimaryKeys( $row ),
+						'changes' => $update,
+					];
+				}
+			}
+
+			if ( $updates ) {
+				$this->output( "Processing " . count( $updates ) . " rows\n" );
+				$this->writer->write( $updates );
+			}
+		}
+
+		$this->output( "Completed\n" );
+	}
+
+	/**
+	 * Accepts a callable which will receive a single parameter
+	 * containing string status updates
+	 *
+	 * @param callable $output A callback taking a single string
+	 *  parameter to output
+	 */
+	public function setOutput( callable $output ) {
+		$this->output = $output;
+	}
+
+	/**
+	 * Write out a status update
+	 *
+	 * @param string $text The value to print
+	 */
+	protected function output( $text ) {
+		call_user_func( $this->output, $text );
+	}
+}