[tracker/wip/carlosg/sparql1.1: 78/80] libtracker-data: Implement ISBLANK()

[Carlos Garnacho <carlosg src gnome org>]

commit 0384b446bb355c11bde0d0e454917809ad3b172c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Jul 7 21:32:00 2019 +0200

    libtracker-data: Implement ISBLANK()

 src/libtracker-data/tracker-sparql.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)
---
diff --git a/src/libtracker-data/tracker-sparql.c b/src/libtracker-data/tracker-sparql.c
index e60629d7a..89e02352f 100644
--- a/src/libtracker-data/tracker-sparql.c
+++ b/src/libtracker-data/tracker-sparql.c
@@ -6978,7 +6978,23 @@ translate_BuiltInCall (TrackerSparql  *sparql,
                _append_string (sparql, "== \"" RDFS_NS "Resource\" ");
                sparql->current_state.expression_type = TRACKER_PROPERTY_TYPE_BOOLEAN;
        } else if (_accept (sparql, RULE_TYPE_LITERAL, LITERAL_ISBLANK)) {
-               _unimplemented ("ISBLANK");
+               _expect (sparql, RULE_TYPE_LITERAL, LITERAL_OPEN_PARENS);
+               node = _skip_rule (sparql, NAMED_RULE_Expression);
+               _expect (sparql, RULE_TYPE_LITERAL, LITERAL_CLOSE_PARENS);
+
+               _append_string (sparql, "CASE ");
+
+               if (!helper_datatype (sparql, node, error))
+                       return FALSE;
+
+               _append_string (sparql, "== \"" RDFS_NS "Resource\" ");
+               _append_string (sparql, "WHEN 1 THEN (SELECT BlankNode FROM Resource WHERE ID = ");
+
+               if (!_postprocess_rule (sparql, node, NULL, error))
+                       return FALSE;
+
+               _append_string (sparql, ") ELSE NULL END ");
+               sparql->current_state.expression_type = TRACKER_PROPERTY_TYPE_BOOLEAN;
        } else if (_accept (sparql, RULE_TYPE_LITERAL, LITERAL_ISLITERAL)) {
                _expect (sparql, RULE_TYPE_LITERAL, LITERAL_OPEN_PARENS);
                node = _skip_rule (sparql, NAMED_RULE_Expression);