libtracker-data: Add SparqlRand sqlite function

This will be used to back up the RAND() sparql 1.1 function. Unlike
the random() sqlite builtin function, g_random_double() gives us
the random number in the same range than described in the
recommendation, so it seems a better fit.

1 files changed, 17 insertions, 0 deletions

diff --git a/src/libtracker-data/tracker-db-interface-sqlite.c b/src/libtracker-data/tracker-db-interface-sqlite.c
index b7d0f834c..bb3ae3b76 100644
--- a/src/libtracker-data/tracker-db-interface-sqlite.c
+++ b/src/libtracker-data/tracker-db-interface-sqlite.c
@@ -1012,6 +1012,19 @@ function_sparql_floor (sqlite3_context *context,
 }
 
 static void
+function_sparql_rand (sqlite3_context *context,
+                      int              argc,
+                      sqlite3_value   *argv[])
+{
+	if (argc != 0) {
+		sqlite3_result_error (context, "Invalid argument count", -1);
+		return;
+	}
+
+	sqlite3_result_double (context, g_random_double ());
+}
+
+static void
 function_sparql_checksum (sqlite3_context *context,
 			  int              argc,
 			  sqlite3_value   *argv[])
@@ -1191,6 +1204,10 @@ open_database (TrackerDBInterface  *db_interface,
 	                         db_interface, &function_sparql_floor,
 	                         NULL, NULL);
 
+	sqlite3_create_function (db_interface->db, "SparqlRand", 0, SQLITE_ANY,
+	                         db_interface, &function_sparql_rand,
+	                         NULL, NULL);
+
 	sqlite3_create_function (db_interface->db, "SparqlChecksum", 2, SQLITE_ANY,
 	                         db_interface, &function_sparql_checksum,
 	                         NULL, NULL);