libtracker-data: Add optional() method for tokens that need no retval checks

Also makes code clearer, as accept() implies you may react differently on
token availability.

https://bugzilla.gnome.org/show_bug.cgi?id=785863

2 files changed, 9 insertions, 0 deletions

diff --git a/src/libtracker-data/tracker-sparql-pattern.vala b/src/libtracker-data/tracker-sparql-pattern.vala
index 37faf28dd..96efc1348 100644
--- a/src/libtracker-data/tracker-sparql-pattern.vala
+++ b/src/libtracker-data/tracker-sparql-pattern.vala
@@ -205,6 +205,10 @@ class Tracker.Sparql.Pattern : Object {
 		return query.accept (type);
 	}
 
+	inline void optional (SparqlTokenType type) throws Sparql.Error {
+		query.optional (type);
+	}
+
 	Sparql.Error get_error (string msg) {
 		return query.get_error (msg);
 	}
diff --git a/src/libtracker-data/tracker-sparql-query.vala b/src/libtracker-data/tracker-sparql-query.vala
index 32d31efa1..e611b0f38 100644
--- a/src/libtracker-data/tracker-sparql-query.vala
+++ b/src/libtracker-data/tracker-sparql-query.vala
@@ -347,6 +347,11 @@ public class Tracker.Sparql.Query : Object {
 		return false;
 	}
 
+	internal void optional (SparqlTokenType type) throws Sparql.Error {
+		if (current () == type)
+			next ();
+	}
+
 	internal Sparql.Error get_error (string msg) {
 		return new Sparql.Error.PARSE ("%d.%d: syntax error, %s".printf (tokens[index].begin.line, tokens[index].begin.column, msg));
 	}