[tracker/wip/carlosg/fix-blank-node-labels] libtracker-data: Fix (again) blank node lifetime handling

[Carlos Garnacho <carlosg src gnome org>]

commit 9fa1fc121c523d5b2a92f9ed859fff85d80a952b
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon May 18 21:43:21 2020 +0200

    libtracker-data: Fix (again) blank node lifetime handling
    
    Commit a6013fe3d92 sloppily tried to fix blank node lifetimes.
    However I missed that the Update rule is defined in a recursive
    manner, so this in essence resulted on the hashtable still being
    created before each individual update, but also leaked and
    overwritten.
    
    Move the hashtable creation/destruction so it truly stays alive
    for the full parsing stage.

 src/libtracker-data/tracker-sparql.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql.c b/src/libtracker-data/tracker-sparql.c
index 130a7072d..5bcc87b9f 100644
--- a/src/libtracker-data/tracker-sparql.c
+++ b/src/libtracker-data/tracker-sparql.c
@@ -194,6 +194,8 @@ tracker_sparql_finalize (GObject *object)
        tracker_token_unset (&sparql->current_state.subject);
        tracker_token_unset (&sparql->current_state.predicate);
        tracker_token_unset (&sparql->current_state.object);
+       g_clear_pointer (&sparql->current_state.blank_node_map,
+                        g_hash_table_unref);
        g_clear_pointer (&sparql->current_state.union_views, g_hash_table_unref);
        g_clear_pointer (&sparql->current_state.construct_query,
                         tracker_string_builder_free);
@@ -2320,8 +2322,11 @@ translate_Update (TrackerSparql  *sparql,
         */
        _call_rule (sparql, NAMED_RULE_Prologue, error);
 
-       sparql->current_state.blank_node_map =
-               g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
+       if (!sparql->current_state.blank_node_map) {
+               sparql->current_state.blank_node_map =
+                       g_hash_table_new_full (g_str_hash, g_str_equal,
+                                              g_free, g_free);
+       }
 
        if (_check_in_rule (sparql, NAMED_RULE_Update1)) {
                if (sparql->blank_nodes)
@@ -2338,9 +2343,6 @@ translate_Update (TrackerSparql  *sparql,
                        _call_rule (sparql, NAMED_RULE_Update, error);
        }
 
-       g_clear_pointer (&sparql->current_state.blank_node_map,
-                        g_hash_table_unref);
-
        return TRUE;
 }