feedparser: check if initial xpath query for root element returns anything

classes/feedparser.php

@@ -51,24 +51,28 @@ class FeedParser {
 
 		$this->xpath = $xpath;
 
-		$root = $xpath->query("(//atom03:feed|//atom:feed|//channel|//rdf:rdf|//rdf:RDF)")->item(0);
+		$root = $xpath->query("(//atom03:feed|//atom:feed|//channel|//rdf:rdf|//rdf:RDF)");
 
 		if ($root) {
-			switch (mb_strtolower($root->tagName)) {
-			case "rdf:rdf":
-				$this->type = $this::FEED_RDF;
-				break;
-			case "channel":
-				$this->type = $this::FEED_RSS;
-				break;
-			case "feed":
-				$this->type = $this::FEED_ATOM;
-				break;
-			default:
-				if( !isset($this->error) ){
-					$this->error = "Unknown/unsupported feed type";
+			$root = $root->item(0);
+
+			if ($root) {
+				switch (mb_strtolower($root->tagName)) {
+				case "rdf:rdf":
+					$this->type = $this::FEED_RDF;
+					break;
+				case "channel":
+					$this->type = $this::FEED_RSS;
+					break;
+				case "feed":
+					$this->type = $this::FEED_ATOM;
+					break;
+				default:
+					if( !isset($this->error) ){
+						$this->error = "Unknown/unsupported feed type";
+					}
+					return;
 				}
-				return;
 			}
 
 			switch ($this->type) {