1 files changed, 110 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/Utils/CircularReferenceGuard.php b/www/wiki/extensions/SemanticMediaWiki/src/Utils/CircularReferenceGuard.php
new file mode 100644
index 00000000..26cb35ec
--- /dev/null
+++ b/www/wiki/extensions/SemanticMediaWiki/src/Utils/CircularReferenceGuard.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace SMW\Utils;
+
+/**
+ * @license GNU GPL v2+
+ * @since 2.2
+ *
+ * @author mwjames
+ */
+class CircularReferenceGuard {
+
+	/**
+	 * @var array
+	 */
+	private static $circularRefGuard = [];
+
+	/**
+	 * @var string
+	 */
+	private $namespace = '';
+
+	/**
+	 * @var integer
+	 */
+	private $maxRecursionDepth = 1;
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param string $namespace
+	 */
+	public function __construct( $namespace = '' ) {
+		$this->namespace = $namespace;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param integer $maxRecursionDepth
+	 */
+	public function setMaxRecursionDepth( $maxRecursionDepth ) {
+		$this->maxRecursionDepth = (int)$maxRecursionDepth;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param string $hash
+	 */
+	public function mark( $hash ) {
+
+		if ( !isset( self::$circularRefGuard[$this->namespace][$hash] ) ) {
+			self::$circularRefGuard[$this->namespace][$hash] = 0;
+		}
+
+		self::$circularRefGuard[$this->namespace][$hash]++;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param string $hash
+	 */
+	public function unmark( $hash ) {
+
+		if ( isset( self::$circularRefGuard[$this->namespace][$hash] ) && self::$circularRefGuard[$this->namespace][$hash] > 0 ) {
+			return self::$circularRefGuard[$this->namespace][$hash]--;
+		}
+
+		unset( self::$circularRefGuard[$this->namespace][$hash] );
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param string $hash
+	 *
+	 * @return boolean
+	 */
+	public function isCircular( $hash ) {
+		return $this->get( $hash ) > $this->maxRecursionDepth;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param string $hash
+	 *
+	 * @return integer
+	 */
+	public function get( $hash ) {
+
+		if ( isset( self::$circularRefGuard[$this->namespace][$hash] ) ) {
+			return self::$circularRefGuard[$this->namespace][$hash];
+		}
+
+		return 0;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param string $namespace
+	 */
+	public function reset( $namespace ) {
+		self::$circularRefGuard[$namespace] =  [];
+	}
+
+}