get_user_theme_path: cache data

functions.php

@@ -1999,13 +1999,19 @@
 			$theme_id = 1;
 		}
 
+		if (!$_SESSION["theme_path"][$theme_id]) {
 			$result = db_query($link, "SELECT theme_path 
 				FROM ttrss_themes	WHERE id = '$theme_id'");
 			if (db_num_rows($result) != 0) {
-			return db_fetch_result($result, 0, "theme_path");
+				$theme = db_fetch_result($result, 0, "theme_path");
+				$_SESSION["theme_path"][$theme_id] = $theme;
+				return $theme;
 			} else {
 				return null;
 			}
+		} else {
+			return $_SESSION["theme_path"][$theme_id];
+		}
 	}
 
 	function smart_date_time($timestamp) {