Move DiffEngine and helpers to includes/libs/Diff and put them in a namespace

I will address the dependencies on MW core in a followup.

Bug: T339184
Change-Id: I892364b0c9f15c9de4cfc29c683670c172d71764

1 files changed, 59 insertions, 0 deletions

diff --git a/includes/libs/Diff/DiffOpChange.php b/includes/libs/Diff/DiffOpChange.php
new file mode 100644
index 000000000000..36003cd7825d
--- /dev/null
+++ b/includes/libs/Diff/DiffOpChange.php
@@ -0,0 +1,59 @@
+<?php
+
+/**
+ * A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
+ *
+ * Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
+ * You may copy this code freely under the conditions of the GPL.
+ *
+ * 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 DifferenceEngine
+ */
+
+namespace Wikimedia\Diff;
+
+/**
+ * Extends DiffOp. Used to mark strings that have been
+ * changed from the first string array (both added and subtracted).
+ *
+ * @internal
+ * @ingroup DifferenceEngine
+ */
+class DiffOpChange extends DiffOp {
+	/** @inheritDoc */
+	public $type = 'change';
+
+	/**
+	 * @param string[] $orig
+	 * @param string[] $closing
+	 */
+	public function __construct( $orig, $closing ) {
+		$this->orig = $orig;
+		$this->closing = $closing;
+	}
+
+	/**
+	 * @return DiffOpChange
+	 */
+	public function reverse() {
+		return new DiffOpChange( $this->closing, $this->orig );
+	}
+}
+
+/** @deprecated since 1.41 */
+class_alias( DiffOpChange::class, 'DiffOpChange' );