Initial sketch for the generic data-transfer interface.

1 files changed, 81 insertions, 0 deletions

diff --git a/src/core/interface.c b/src/core/interface.c
new file mode 100644
index 00000000..15df49d3
--- /dev/null
+++ b/src/core/interface.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <assert.h>
+#include <gpxe/interface.h>
+
+/** @file
+ *
+ * Object communication interfaces
+ *
+ */
+
+/**
+ * Obtain reference to interface
+ *
+ * @v intf		Interface
+ * @ret intf		Interface
+ *
+ * Increases the reference count on the interface.
+ */
+static struct interface * intf_get ( struct interface *intf ) {
+	intf->refcnt ( intf, +1 );
+	return intf;
+}
+
+/**
+ * Drop reference to interface
+ *
+ * @v intf		Interface
+ *
+ * Decreases the reference count on the interface.
+ */
+static void intf_put ( struct interface *intf ) {
+	intf->refcnt ( intf, -1 );
+}
+
+/**
+ * Plug an interface into a new destination interface
+ *
+ * @v intf		Interface
+ * @v dest		New destination interface
+ *
+ * The reference to the existing destination interface is dropped, a
+ * reference to the new destination interface is obtained, and the
+ * interface is updated to point to the new destination interface.
+ *
+ * Note that there is no "unplug" call; instead you must plug the
+ * interface into a null interface.
+ */
+void plug ( struct interface *intf, struct interface *dest ) {
+	intf_put ( intf->dest );
+	intf->dest = intf_get ( dest );
+}
+
+/**
+ * Null update reference count
+ *
+ * @v intf		Interface
+ * @v delta		Change to apply to reference count
+ *
+ * Use this as the refcnt() method for an interface that does not need
+ * to support reference counting.
+ */
+void null_refcnt ( struct interface *intf __unused, int delta __unused ) {
+	/* Do nothing */
+}