[tracker/wip/carlosg/resource-leak-fix: 3/5] libtracker-data: Add resource element triggers

[Carlos Garnacho <carlosg src gnome org>]

commit 0a96db167f80aadd6007576762eebb1eb8c71918
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Jul 5 10:56:46 2017 +0200

    libtracker-data: Add resource element triggers
    
    Those will control the Refcount column in the Resource table,
    whenever a resource is added/removed from a resource or multivalued
    property table, or whenever a single or multivalued property points
    or stops pointing to a given resource, its refcount will be changed.
    
    This adds automatic refcounting on elements, so we can tell those
    with a refcount=0 are not referenced anywhere so thus can be dropped.

 src/libtracker-data/tracker-data-manager.c |  116 ++++++++++++++++++++++++++++
 1 files changed, 116 insertions(+), 0 deletions(-)
---
diff --git a/src/libtracker-data/tracker-data-manager.c b/src/libtracker-data/tracker-data-manager.c
index 05d8947..c7bea50 100644
--- a/src/libtracker-data/tracker-data-manager.c
+++ b/src/libtracker-data/tracker-data-manager.c
@@ -2901,6 +2901,118 @@ schedule_copy (GPtrArray *schedule,
 }
 
 static void
+create_triggers_on_rowid (TrackerDBInterface  *iface,
+                          TrackerClass        *klass,
+                          TrackerProperty     *property,
+                          GError             **error)
+{
+       GError *internal_error = NULL;
+       gchar *table_name;
+
+       if (property) {
+               table_name = g_strdup_printf ("%s_%s",
+                                             tracker_class_get_name (klass),
+                                             tracker_property_get_name (property));
+       } else {
+               table_name = g_strdup (tracker_class_get_name (klass));
+       }
+
+       tracker_db_interface_execute_query (iface, &internal_error,
+                                           "CREATE TRIGGER \"trigger_insert_%s\" "
+                                           "AFTER INSERT ON \"%s\" "
+                                           "FOR EACH ROW BEGIN "
+                                           "UPDATE Resource SET Refcount = Refcount + 1 WHERE Resource.rowid 
= NEW.ID;"
+                                           "END",
+                                           table_name, table_name);
+       if (internal_error) {
+               g_propagate_error (error, internal_error);
+               g_free (table_name);
+               return;
+       }
+
+       tracker_db_interface_execute_query (iface, &internal_error,
+                                           "CREATE TRIGGER \"trigger_delete_%s\" "
+                                           "AFTER DELETE ON \"%s\" "
+                                           "FOR EACH ROW BEGIN "
+                                           "UPDATE Resource SET Refcount = Refcount - 1 WHERE Resource.rowid 
= OLD.ID;"
+                                           "END",
+                                           table_name, table_name);
+       if (internal_error) {
+               g_propagate_error (error, internal_error);
+               g_free (table_name);
+               return;
+       }
+
+       g_free (table_name);
+}
+
+static void
+create_table_triggers (TrackerDataManager  *manager,
+                       TrackerDBInterface  *iface,
+                       TrackerClass        *klass,
+                       GError             **error)
+{
+       const gchar *property_name;
+       TrackerProperty **properties, *property;
+       GError *internal_error = NULL;
+       guint i, n_props;
+
+       create_triggers_on_rowid (iface, klass, NULL, &internal_error);
+       if (internal_error) {
+               g_propagate_error (error, internal_error);
+               return;
+       }
+
+       properties = tracker_ontologies_get_properties (manager->ontologies, &n_props);
+
+       for (i = 0; i < n_props; i++) {
+               gboolean multivalued;
+               gchar *table_name;
+
+               property = properties[i];
+
+               if (tracker_property_get_domain (property) != klass ||
+                   tracker_property_get_data_type (property) != TRACKER_PROPERTY_TYPE_RESOURCE)
+                       continue;
+
+               property_name = tracker_property_get_name (property);
+               multivalued = tracker_property_get_multiple_values (property);
+
+               if (multivalued) {
+                       create_triggers_on_rowid (iface, klass, property, &internal_error);
+                       if (internal_error) {
+                               g_propagate_error (error, internal_error);
+                               return;
+                       }
+
+                       table_name = g_strdup_printf ("%s_%s",
+                                                     tracker_class_get_name (klass),
+                                                     property_name);
+               } else {
+                       table_name = g_strdup (tracker_class_get_name (klass));
+               }
+
+               tracker_db_interface_execute_query (iface, &internal_error,
+                                                   "CREATE TRIGGER \"trigger_update_%s_%s\" "
+                                                   "AFTER UPDATE OF \"%s\" ON \"%s\" "
+                                                   "FOR EACH ROW BEGIN "
+                                                   "UPDATE Resource SET Refcount = Refcount + 1 WHERE 
Resource.rowid = NEW.\"%s\";"
+                                                   "UPDATE Resource SET Refcount = Refcount - 1 WHERE 
Resource.rowid = OLD.\"%s\";"
+                                                   "END",
+                                                   tracker_class_get_name (klass),
+                                                   property_name,
+                                                   property_name, table_name,
+                                                   property_name, property_name);
+               g_free (table_name);
+
+               if (internal_error) {
+                       g_propagate_error (error, internal_error);
+                       return;
+               }
+       }
+}
+
+static void
 create_decomposed_metadata_tables (TrackerDataManager  *manager,
                                    TrackerDBInterface  *iface,
                                    TrackerClass        *service,
@@ -2912,6 +3024,7 @@ create_decomposed_metadata_tables (TrackerDataManager  *manager,
        GString          *create_sql = NULL;
        GString          *in_col_sql = NULL;
        GString          *sel_col_sql = NULL;
+       GString          *trigger_sql = NULL;
        TrackerProperty **properties, *property, **domain_indexes;
        GSList           *class_properties = NULL, *field_it;
        gboolean          main_class;
@@ -3203,6 +3316,9 @@ create_decomposed_metadata_tables (TrackerDataManager  *manager,
                tracker_db_interface_execute_query (iface, &internal_error,
                                                    "%s", create_sql->str);
 
+               if (!internal_error)
+                       create_table_triggers (manager, iface, service, &internal_error);
+
                if (internal_error) {
                        g_propagate_error (error, internal_error);
                        goto error_out;