Add function for finding urls in string

https://bugzilla.gnome.org/show_bug.cgi?id=610219

js/Makefile.am

@@ -8,6 +8,7 @@ nobase_dist_js_DATA = 	\
 	misc/gnomeSession.js	\
 	misc/params.js		\
 	misc/telepathy.js	\
+	misc/utils.js		\
 	perf/core.js		\
 	prefs/clockPreferences.js \
 	ui/altTab.js		\

js/misc/utils.js

@@ -0,0 +1,19 @@
+/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
+
+/* http://daringfireball.net/2010/07/improved_regex_for_matching_urls */
+const _urlRegexp = /\b(([a-z][\w-]+:(\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)([^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'\".,<>?«»“”‘’]))/gi;
+
+// findUrls:
+// @str: string to find URLs in
+//
+// Searches @str for URLs and returns an array of objects with %url
+// properties showing the matched URL string, and %pos properties indicating
+// the position within @str where the URL was found.
+//
+// Return value: the list of match objects, as described above
+function findUrls(str) {
+    let res = [], match;
+    while ((match = _urlRegexp.exec(str)))
+        res.push({ url: match[0], pos: match.index });
+    return res;
+}