[tracker/wip/carlosg/sparql1.1: 40/56] libtracker-data: Add support for CONSTRUCT/DESCRIBE

[Carlos Garnacho <carlosg src gnome org>]

commit a73031e8b5f51e629fff5dc525ec12f2d89bb536
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Jun 1 18:13:27 2019 +0200

    libtracker-data: Add support for CONSTRUCT/DESCRIBE

 src/libtracker-data/tracker-sparql.c | 100 ++++++++++++++++++++++++++++++++++-
 1 file changed, 98 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql.c b/src/libtracker-data/tracker-sparql.c
index e9de9d703..0ec8a2476 100644
--- a/src/libtracker-data/tracker-sparql.c
+++ b/src/libtracker-data/tracker-sparql.c
@@ -1951,14 +1951,107 @@ static gboolean
 translate_ConstructQuery (TrackerSparql  *sparql,
                           GError        **error)
 {
-       _unimplemented ("CONSTRUCT");
+       /* ConstructQuery ::= 'CONSTRUCT' ( ConstructTemplate DatasetClause* WhereClause SolutionModifier |
+        *                                  DatasetClause* 'WHERE' '{' TriplesTemplate? '}' SolutionModifier )
+        */
+       sparql->context = g_object_ref_sink (tracker_select_context_new ());
+       sparql->current_state.select_context = sparql->context;
+       tracker_sparql_push_context (sparql, sparql->context);
+
+       _expect (sparql, RULE_TYPE_LITERAL, LITERAL_CONSTRUCT);
+
+       if (_current_rule (sparql) == NAMED_RULE_ConstructTemplate) {
+               _call_rule (sparql, NAMED_RULE_ConstructTemplate, error);
+
+               while (_current_rule (sparql) == NAMED_RULE_DatasetClause)
+                       _call_rule (sparql, NAMED_RULE_DatasetClause, error);
+
+               _call_rule (sparql, NAMED_RULE_WhereClause, error);
+               _call_rule (sparql, NAMED_RULE_SolutionModifier, error);
+       } else {
+               while (_current_rule (sparql) == NAMED_RULE_DatasetClause)
+                       _call_rule (sparql, NAMED_RULE_DatasetClause, error);
+
+               _expect (sparql, RULE_TYPE_LITERAL, LITERAL_WHERE);
+               _expect (sparql, RULE_TYPE_LITERAL, LITERAL_OPEN_BRACE);
+
+               if (_current_rule (sparql) == NAMED_RULE_TriplesTemplate) {
+                       _begin_triples_block (sparql);
+                       _call_rule (sparql, NAMED_RULE_TriplesTemplate, error);
+                       if (!_end_triples_block (sparql, error))
+                               return FALSE;
+               }
+
+               _expect (sparql, RULE_TYPE_LITERAL, LITERAL_CLOSE_BRACE);
+               _call_rule (sparql, NAMED_RULE_SolutionModifier, error);
+       }
+
+       tracker_sparql_pop_context (sparql, FALSE);
+
+       return TRUE;
 }
 
 static gboolean
 translate_DescribeQuery (TrackerSparql  *sparql,
                          GError        **error)
 {
-       _unimplemented ("DESCRIBE");
+       /* DescribeQuery ::= 'DESCRIBE' ( VarOrIri+ | '*' ) DatasetClause* WhereClause? SolutionModifier
+        */
+       sparql->context = g_object_ref_sink (tracker_select_context_new ());
+       sparql->current_state.select_context = sparql->context;
+       tracker_sparql_push_context (sparql, sparql->context);
+
+       _expect (sparql, RULE_TYPE_LITERAL, LITERAL_DESCRIBE);
+       _append_string (sparql,
+                       "SELECT "
+                       "  (SELECT Uri FROM Resource WHERE ID = subject),"
+                       "  (SELECT Uri FROM Resource WHERE ID = predicate),"
+                       "  object "
+                       "FROM tracker_triples "
+                       "WHERE object IS NOT NULL AND subject IN (");
+
+       if (_accept (sparql, RULE_TYPE_LITERAL, LITERAL_GLOB)) {
+       } else {
+               TrackerContext *context;
+
+               context = tracker_triple_context_new ();
+               tracker_sparql_push_context (sparql, context);
+
+               while (_check_in_rule (sparql, NAMED_RULE_VarOrIri)) {
+                       TrackerBinding *binding;
+                       TrackerToken resource;
+
+                       _call_rule (sparql, NAMED_RULE_VarOrIri, error);
+                       _init_token (&resource, sparql->current_state.prev_node, sparql);
+
+                       if (tracker_token_get_literal (&resource)) {
+                               binding = tracker_literal_binding_new (tracker_token_get_literal (&resource),
+                                                                      NULL);
+                               tracker_binding_set_data_type (binding, TRACKER_PROPERTY_TYPE_RESOURCE);
+                               _add_binding (sparql, binding);
+                               _append_literal_sql (sparql, TRACKER_LITERAL_BINDING (binding));
+                       } else {
+                       }
+
+                       tracker_token_unset (&resource);
+               }
+
+               tracker_sparql_pop_context (sparql, FALSE);
+       }
+
+       while (_check_in_rule (sparql, NAMED_RULE_DatasetClause))
+               _call_rule (sparql, NAMED_RULE_DatasetClause, error);
+
+       if (_check_in_rule (sparql, NAMED_RULE_WhereClause)) {
+               _append_string (sparql, "SELECT * ");
+               _call_rule (sparql, NAMED_RULE_WhereClause, error);
+       }
+
+       _call_rule (sparql, NAMED_RULE_SolutionModifier, error);
+       tracker_sparql_pop_context (sparql, FALSE);
+       _append_string (sparql, ") ");
+
+       return TRUE;
 }
 
 static gboolean
@@ -3810,12 +3903,15 @@ translate_ConstructTemplate (TrackerSparql  *sparql,
        /* ConstructTemplate ::= '{' ConstructTriples? '}'
         */
        _expect (sparql, RULE_TYPE_LITERAL, LITERAL_OPEN_BRACE);
+       _begin_triples_block (sparql);
 
        if (_check_in_rule (sparql, NAMED_RULE_ConstructTriples)) {
                _call_rule (sparql, NAMED_RULE_ConstructTriples, error);
        }
 
        _expect (sparql, RULE_TYPE_LITERAL, LITERAL_CLOSE_BRACE);
+       if (!_end_triples_block (sparql, error))
+               return FALSE;
 
        return TRUE;
 }