Added a simple pass-through filter layer for data transfer interfaces.

src/core/filter.c

@@ -0,0 +1,78 @@
+/*
+ * 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 <gpxe/xfer.h>
+#include <gpxe/filter.h>
+
+/** @file
+ *
+ * Data transfer filters
+ *
+ */
+
+/*
+ * Pass-through methods to be used by filters which don't want to
+ * intercept all events.
+ *
+ */
+
+void filter_close ( struct xfer_interface *xfer, int rc ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	xfer_close ( other, rc );
+}
+
+int filter_vredirect ( struct xfer_interface *xfer, int type,
+			va_list args ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	return xfer_vredirect ( other, type, args );
+}
+
+int filter_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	return xfer_seek ( other, offset, whence );
+}
+
+size_t filter_window ( struct xfer_interface *xfer ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	return xfer_window ( other );
+}
+
+struct io_buffer * filter_alloc_iob ( struct xfer_interface *xfer,
+				      size_t len ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	return xfer_alloc_iob ( other, len );
+}
+
+int filter_deliver_iob ( struct xfer_interface *xfer, struct io_buffer *iobuf,
+			 struct xfer_metadata *meta ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	return xfer_deliver_iob_meta ( other, iobuf, meta );
+}
+
+int filter_deliver_raw ( struct xfer_interface *xfer, const void *data,
+			 size_t len ) {
+	struct xfer_interface *other = filter_other_half ( xfer );
+
+	return xfer_deliver_raw ( other, data, len );
+}

src/include/gpxe/filter.h

@@ -0,0 +1,75 @@
+#ifndef _GPXE_FILTER_H
+#define _GPXE_FILTER_H
+
+/** @file
+ *
+ * Data transfer filters
+ *
+ */
+
+#include <stddef.h>
+#include <gpxe/xfer.h>
+
+/**
+ * Half of a data transfer filter
+ *
+ * Embed two of these structures within a structure implementing a
+ * data transfer filter, and intialise with filter_init().  You can
+ * then use the filter_xxx() methods as the data transfer interface
+ * methods as required.
+ */
+struct xfer_filter_half {
+	/** Data transfer interface */
+	struct xfer_interface xfer;
+	/** Other half of the data transfer filter */
+	struct xfer_filter_half *other;
+};
+
+/**
+ * Get data transfer interface for the other half of a data transfer filter
+ *
+ * @v xfer		Data transfer interface
+ * @ret other		Other half's data transfer interface
+ */
+static inline __attribute__ (( always_inline )) struct xfer_interface *
+filter_other_half ( struct xfer_interface *xfer ) {
+	struct xfer_filter_half *half = 
+		container_of ( xfer, struct xfer_filter_half, xfer );
+	return &half->other->xfer;
+}
+
+extern void filter_close ( struct xfer_interface *xfer, int rc );
+extern int filter_vredirect ( struct xfer_interface *xfer, int type,
+			      va_list args );
+extern int filter_seek ( struct xfer_interface *xfer, off_t offset,
+			 int whence );
+extern size_t filter_window ( struct xfer_interface *xfer );
+extern struct io_buffer * filter_alloc_iob ( struct xfer_interface *xfer,
+					     size_t len );
+extern int filter_deliver_iob ( struct xfer_interface *xfer,
+				struct io_buffer *iobuf,
+				struct xfer_metadata *meta );
+extern int filter_deliver_raw ( struct xfer_interface *xfer, const void *data,
+				size_t len );
+
+/**
+ * Initialise a data transfer filter
+ *
+ * @v left		"Left" half of the filter
+ * @v left_op		Data transfer interface operations for "left" half
+ * @v right		"Right" half of the filter
+ * @v right_op		Data transfer interface operations for "right" half
+ * @v refcnt		Containing object reference counter, or NULL
+ */
+static inline void filter_init ( struct xfer_filter_half *left,
+				 struct xfer_interface_operations *left_op,
+				 struct xfer_filter_half *right,
+				 struct xfer_interface_operations *right_op,
+				 struct refcnt *refcnt ) {
+	xfer_init ( &left->xfer, left_op, refcnt );
+	xfer_init ( &right->xfer, right_op, refcnt );
+	left->other = right;
+	right->other = left;
+}
+
+#endif /* _GPXE_FILTER_H */