[tracker-miners/wip/carlosg/miner-changes: 10/17] libtracker-miner: Use TrackerSparqlStatement in TrackerDecorator

[Carlos Garnacho <carlosg src gnome org>]

commit 0a0c3f0c4e89f8a60b6a3dc8c98668f037cd9820
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Jun 17 12:55:27 2020 +0200

    libtracker-miner: Use TrackerSparqlStatement in TrackerDecorator

 src/libtracker-miner/tracker-decorator.c | 112 ++++++++++++++++++++-----------
 1 file changed, 73 insertions(+), 39 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-decorator.c b/src/libtracker-miner/tracker-decorator.c
index c7f56ae7d..1dc730706 100644
--- a/src/libtracker-miner/tracker-decorator.c
+++ b/src/libtracker-miner/tracker-decorator.c
@@ -88,6 +88,9 @@ struct _TrackerDecoratorPrivate {
        GTimer *timer;
        GQueue next_elem_queue; /* Queue of incoming tasks */
 
+       TrackerSparqlStatement *remaining_items_query;
+       TrackerSparqlStatement *item_count_query;
+
        GCancellable *cancellable;
 
        gint batch_size;
@@ -584,7 +587,6 @@ static gchar *
 create_query_string (TrackerDecorator  *decorator,
                      gchar            **select_clauses)
 {
-       TrackerDecoratorPrivate *priv = decorator->priv;
        const gchar *graphs[] = {
                "tracker:Audio",
                "tracker:Pictures",
@@ -593,7 +595,7 @@ create_query_string (TrackerDecorator  *decorator,
                "tracker:Documents",
        };
        GString *query;
-       gint i, offset;
+       gint i;
 
        query = g_string_new ("SELECT ");
 
@@ -613,26 +615,47 @@ create_query_string (TrackerDecorator  *decorator,
                                        graphs[i]);
        }
 
-       offset = g_hash_table_size (priv->tasks);
-       if (priv->sparql_buffer)
-               offset += priv->sparql_buffer->len;
-       if (priv->commit_buffer)
-               offset += priv->commit_buffer->len;
-
        g_string_append_printf (query,
                                "FILTER (NOT EXISTS {"
                                "  GRAPH tracker:FileSystem { ?urn tracker:extractorHash ?hash }"
                                "})"
-                               "} OFFSET %d LIMIT %d",
-                               offset,
+                               "} OFFSET ~offset LIMIT %d",
                                QUERY_BATCH_SIZE);
 
        return g_string_free (query, FALSE);
 }
 
-static gchar *
-create_remaining_items_query (TrackerDecorator *decorator)
+static TrackerSparqlStatement *
+create_prepared_statement (TrackerDecorator  *decorator,
+                           gchar            **select_clauses)
+{
+       TrackerDecoratorPrivate *priv = decorator->priv;
+       TrackerSparqlConnection *sparql_conn;
+       TrackerSparqlStatement *statement;
+       GError *error = NULL;
+       gchar *query;
+
+       query = create_query_string (decorator, select_clauses);
+
+       sparql_conn = tracker_miner_get_connection (TRACKER_MINER (decorator));
+       statement = tracker_sparql_connection_query_statement (sparql_conn,
+                                                              query,
+                                                              priv->cancellable,
+                                                              &error);
+       g_free (query);
+
+       if (error) {
+               g_warning ("Could not create statement: %s", error->message);
+               g_error_free (error);
+       }
+
+       return statement;
+}
+
+static TrackerSparqlStatement *
+ensure_remaining_items_query (TrackerDecorator *decorator)
 {
+       TrackerDecoratorPrivate *priv = decorator->priv;
        gchar *clauses[] = {
                "?urn",
                "tracker:id(?urn)",
@@ -641,7 +664,10 @@ create_remaining_items_query (TrackerDecorator *decorator)
                NULL
        };
 
-       return create_query_string (decorator, clauses);
+       if (!priv->remaining_items_query)
+               priv->remaining_items_query = create_prepared_statement (decorator, clauses);
+
+       return priv->remaining_items_query;
 }
 
 static void
@@ -654,8 +680,8 @@ decorator_query_remaining_items_cb (GObject      *object,
        TrackerSparqlCursor *cursor;
        GError *error = NULL;
 
-       cursor = tracker_sparql_connection_query_finish (TRACKER_SPARQL_CONNECTION (object),
-                                                        result, &error);
+       cursor = tracker_sparql_statement_execute_finish (TRACKER_SPARQL_STATEMENT (object),
+                                                         result, &error);
 
        if (error || !tracker_sparql_cursor_next (cursor, NULL, &error)) {
                decorator_notify_task_error (decorator, error);
@@ -681,20 +707,21 @@ decorator_query_remaining_items_cb (GObject      *object,
 static void
 decorator_query_remaining_items (TrackerDecorator *decorator)
 {
-       gchar *query, *clauses[] = { "COUNT(?urn)", NULL };
-       TrackerSparqlConnection *sparql_conn;
+       gchar *clauses[] = { "COUNT(?urn)", NULL };
        TrackerDecoratorPrivate *priv;
 
        priv = decorator->priv;
-       query = create_query_string (decorator, clauses);
-
-       if (query) {
-               sparql_conn = tracker_miner_get_connection (TRACKER_MINER (decorator));
-               tracker_sparql_connection_query_async (sparql_conn, query,
-                                                      priv->cancellable,
-                                                      decorator_query_remaining_items_cb,
-                                                      decorator);
-               g_free (query);
+
+       if (!priv->item_count_query)
+               priv->item_count_query = create_prepared_statement (decorator, clauses);
+
+       if (priv->item_count_query) {
+               tracker_sparql_statement_bind_int (priv->item_count_query,
+                                                  "offset", 0);
+               tracker_sparql_statement_execute_async (priv->item_count_query,
+                                                       priv->cancellable,
+                                                       decorator_query_remaining_items_cb,
+                                                       decorator);
        } else {
                decorator_notify_empty (decorator);
        }
@@ -750,13 +777,12 @@ decorator_cache_items_cb (GObject      *object,
 {
        TrackerDecorator *decorator = user_data;
        TrackerDecoratorPrivate *priv;
-       TrackerSparqlConnection *conn;
        TrackerSparqlCursor *cursor;
        TrackerDecoratorInfo *info;
        GError *error = NULL;
 
-       conn = TRACKER_SPARQL_CONNECTION (object);
-       cursor = tracker_sparql_connection_query_finish (conn, result, &error);
+       cursor = tracker_sparql_statement_execute_finish (TRACKER_SPARQL_STATEMENT (object),
+                                                         result, &error);
        priv = decorator->priv;
         priv->querying = FALSE;
 
@@ -798,16 +824,21 @@ decorator_cache_next_items (TrackerDecorator *decorator)
        if (priv->n_remaining_items == 0) {
                decorator_query_remaining_items (decorator);
        } else {
-               TrackerSparqlConnection *sparql_conn;
-               gchar *query;
-
-               sparql_conn = tracker_miner_get_connection (TRACKER_MINER (decorator));
-               query = create_remaining_items_query (decorator);
-               tracker_sparql_connection_query_async (sparql_conn, query,
-                                                      priv->cancellable,
-                                                      decorator_cache_items_cb,
-                                                      decorator);
-               g_free (query);
+               TrackerSparqlStatement *statement;
+               gint offset;
+
+               offset = g_hash_table_size (priv->tasks);
+               if (priv->sparql_buffer)
+                       offset += priv->sparql_buffer->len;
+               if (priv->commit_buffer)
+                       offset += priv->commit_buffer->len;
+
+               statement = ensure_remaining_items_query (decorator);
+               tracker_sparql_statement_bind_int (statement, "offset", offset);
+               tracker_sparql_statement_execute_async (statement,
+                                                       priv->cancellable,
+                                                       decorator_cache_items_cb,
+                                                       decorator);
        }
 }
 
@@ -990,6 +1021,9 @@ tracker_decorator_finalize (GObject *object)
        decorator = TRACKER_DECORATOR (object);
        priv = decorator->priv;
 
+       g_clear_object (&priv->remaining_items_query);
+       g_clear_object (&priv->item_count_query);
+
        g_cancellable_cancel (priv->cancellable);
        g_clear_object (&priv->cancellable);