[tracker/wip/carlosg/bindings-in-service: 4/6] libtracker-data: Proxy parameters to the "services" virtual table

[Carlos Garnacho <carlosg src gnome org>]

commit 8e168916d81dc0bdf68848390bde45df9639e429
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon May 4 19:28:38 2020 +0200

    libtracker-data: Proxy parameters to the "services" virtual table
    
    Look up the parameters used within the service graph pattern, and
    ensure those are proxied to the tracker_services virtual table via
    their valuename/value column pairs.
    
    This pieces everything together in supporting ~var bindings within
    SERVICE{} clauses.
    
    Fixes: https://gitlab.gnome.org/GNOME/tracker/-/issues/200

 src/libtracker-data/tracker-sparql.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)
---
diff --git a/src/libtracker-data/tracker-sparql.c b/src/libtracker-data/tracker-sparql.c
index c16c3a19b..08d2e6524 100644
--- a/src/libtracker-data/tracker-sparql.c
+++ b/src/libtracker-data/tracker-sparql.c
@@ -4662,9 +4662,16 @@ translate_ServiceGraphPattern (TrackerSparql  *sparql,
 
        for (l = variable_rules; l; l = l->next) {
                TrackerParserNode *node = l->data;
+               const TrackerGrammarRule *rule;
                TrackerBinding *binding;
                TrackerVariable *var;
 
+               rule = tracker_parser_node_get_rule (node);
+
+               if (tracker_grammar_rule_is_a (rule, RULE_TYPE_TERMINAL,
+                                              TERMINAL_TYPE_PARAMETERIZED_VAR))
+                       continue;
+
                if (i > 0)
                        _append_string (sparql, ", ");
 
@@ -4674,7 +4681,6 @@ translate_ServiceGraphPattern (TrackerSparql  *sparql,
                binding = tracker_variable_binding_new (var, NULL, NULL);
                _add_binding (sparql, binding);
 
-
                _append_string_printf (sparql, "col%d AS %s ",
                                       i, tracker_variable_get_sql_expression (var));
                g_string_append_printf (service_sparql, "?%s ", var_str);
@@ -4694,6 +4700,33 @@ translate_ServiceGraphPattern (TrackerSparql  *sparql,
                               service_sparql->str,
                               silent);
 
+       i = 0;
+
+       /* Proxy parameters to the virtual table */
+       for (l = variable_rules; l; l = l->next) {
+               TrackerParserNode *node = l->data;
+               const TrackerGrammarRule *rule;
+               TrackerBinding *binding;
+               gchar *name;
+
+               rule = tracker_parser_node_get_rule (node);
+
+               if (!tracker_grammar_rule_is_a (rule, RULE_TYPE_TERMINAL,
+                                               TERMINAL_TYPE_PARAMETERIZED_VAR))
+                       continue;
+
+               name = _extract_node_string (node, sparql);
+               binding = tracker_parameter_binding_new (name, NULL);
+               _add_binding (sparql, binding);
+
+               _append_string_printf (sparql,
+                                      "AND valuename%d = \"%s\" AND value%d = ",
+                                      i, name, i);
+               _append_literal_sql (sparql, TRACKER_LITERAL_BINDING (binding));
+               g_free (name);
+               i++;
+       }
+
        tracker_token_unset (&service);
        tracker_sparql_pop_context (sparql, TRUE);
        g_string_free (service_sparql, TRUE);