[tracker/wip/carlosg/resource-leak-fix: 1/5] libtracker-data: Refactor Resource table creation

[Carlos Garnacho <carlosg src gnome org>]

commit bcee39a447d48afdd8f68b7a035c735de0fefcc2
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Jul 5 10:45:42 2017 +0200

    libtracker-data: Refactor Resource table creation
    
    Instead of creating it just in time for the rdfs:Resource table,
    create it in advance so we have a common hook for other essential
    tables.
    
    The "Available" column that we add to the main class is kind of
    useless, but is preserved so older Tracker versions don't stumble
    on a database created with a more modern Tracker.
    
    We are also adding a "Refcount" column to the Resource table, which
    will be used in the following commits.

 src/libtracker-data/tracker-data-manager.c |   70 +++++++++++++++++++++++++--
 src/libtracker-data/tracker-data-update.c  |    4 +-
 2 files changed, 66 insertions(+), 8 deletions(-)
---
diff --git a/src/libtracker-data/tracker-data-manager.c b/src/libtracker-data/tracker-data-manager.c
index 737b2f8..aa0c127 100644
--- a/src/libtracker-data/tracker-data-manager.c
+++ b/src/libtracker-data/tracker-data-manager.c
@@ -2953,12 +2953,8 @@ create_decomposed_metadata_tables (TrackerDataManager  *manager,
                create_sql = g_string_new ("");
                g_string_append_printf (create_sql, "CREATE TABLE \"%s\" (ID INTEGER NOT NULL PRIMARY KEY", 
service_name);
                if (main_class) {
-                       tracker_db_interface_execute_query (iface, &internal_error, "CREATE TABLE Resource 
(ID INTEGER NOT NULL PRIMARY KEY, Uri TEXT NOT NULL, UNIQUE (Uri))");
-                       if (internal_error) {
-                               g_propagate_error (error, internal_error);
-                               goto error_out;
-                       }
-                       g_string_append (create_sql, ", Available INTEGER NOT NULL");
+                       /* FIXME: This column is unneeded */
+                       g_string_append (create_sql, ", Available INTEGER DEFAULT 1");
                }
        }
 
@@ -3424,6 +3420,63 @@ tracker_data_ontology_import_finished (TrackerDataManager *manager)
        }
 }
 
+static gboolean
+query_table_exists (TrackerDBInterface  *iface,
+                    const gchar         *table_name,
+                    GError             **error)
+{
+       TrackerDBCursor *cursor = NULL;
+       TrackerDBStatement *stmt;
+       gboolean exists = FALSE;
+
+       stmt = tracker_db_interface_create_statement (iface, TRACKER_DB_STATEMENT_CACHE_TYPE_SELECT, error,
+                                                     "SELECT 1 FROM sqlite_master WHERE tbl_name=\"%s\" AND 
type=\"table\"",
+                                                     table_name);
+       if (stmt) {
+               cursor = tracker_db_statement_start_cursor (stmt, error);
+               g_object_unref (stmt);
+       }
+
+       if (cursor) {
+               if (tracker_db_cursor_iter_next (cursor, NULL, error)) {
+                       exists = TRUE;
+               }
+               g_object_unref (cursor);
+       }
+
+       return exists;
+}
+
+static gboolean
+create_base_tables (TrackerDataManager  *manager,
+                    TrackerDBInterface  *iface,
+                    gboolean            *altered,
+                    GError             **error)
+{
+       GError *internal_error = NULL;
+
+       if (!query_table_exists (iface, "Resource", &internal_error) && !internal_error) {
+               tracker_db_interface_execute_query (iface, &internal_error,
+                                                   "CREATE TABLE Resource (ID INTEGER NOT NULL PRIMARY KEY,"
+                                                   " Uri TEXT NOT NULL, Refcount INTEGER DEFAULT 0, UNIQUE 
(Uri))");
+       } else if (!internal_error) {
+               tracker_db_interface_execute_query (iface, &internal_error,
+                                                   "ALTER TABLE Resource ADD COLUMN Refcount INTEGER DEFAULT 
0");
+
+               if (!internal_error)
+                       *altered = TRUE;
+               else
+                       g_clear_error (&internal_error);
+       }
+
+       if (internal_error) {
+               g_propagate_error (error, internal_error);
+               return FALSE;
+       }
+
+       return TRUE;
+}
+
 static void
 tracker_data_ontology_import_into_db (TrackerDataManager  *manager,
                                       gboolean             in_update,
@@ -3434,12 +3487,17 @@ tracker_data_ontology_import_into_db (TrackerDataManager  *manager,
        TrackerClass **classes;
        TrackerProperty **properties;
        guint i, n_props, n_classes;
+       gboolean base_tables_altered = FALSE;
 
        iface = tracker_db_manager_get_writable_db_interface (manager->db_manager);
 
        classes = tracker_ontologies_get_classes (manager->ontologies, &n_classes);
        properties = tracker_ontologies_get_properties (manager->ontologies, &n_props);
 
+       if (!create_base_tables (manager, iface, &base_tables_altered, error)) {
+               return;
+       }
+
        /* create tables */
        for (i = 0; i < n_classes; i++) {
                GError *internal_error = NULL;
diff --git a/src/libtracker-data/tracker-data-update.c b/src/libtracker-data/tracker-data-update.c
index 927aa1e..03697ee 100644
--- a/src/libtracker-data/tracker-data-update.c
+++ b/src/libtracker-data/tracker-data-update.c
@@ -917,8 +917,8 @@ tracker_data_resource_buffer_flush (TrackerData  *data,
                                g_string_append (sql, "\" (ID");
 
                                if (strcmp (table_name, "rdfs:Resource") == 0) {
-                                       g_string_append (sql, ", \"tracker:added\", \"tracker:modified\", 
Available");
-                                       g_string_append (values_sql, ", ?, ?, 1");
+                                       g_string_append (sql, ", \"tracker:added\", \"tracker:modified\"");
+                                       g_string_append (values_sql, ", ?, ?");
                                } else {
                                }
                        } else {