template: A minimal example xlator to build on

This xlator is intended to save new GlusterFS developers
from fighting it with autotools.

How to add template xl onto the xlator graph?
[..]

volname-template
type testing/features/template
subvolumes volname-dht
end-volume

[..]

Change-Id: If513284bb590be7c3b093054108dba2883064190
BUG: 916985
Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-on: http://review.gluster.org/4604
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

configure.ac

@@ -116,6 +116,9 @@ AC_CONFIG_FILES([Makefile
                 xlators/features/index/src/Makefile
 		xlators/features/protect/Makefile
 		xlators/features/protect/src/Makefile
+                xlators/playground/Makefile
+		xlators/playground/template/Makefile
+		xlators/playground/template/src/Makefile
 		xlators/encryption/Makefile
 		xlators/encryption/rot-13/Makefile
 		xlators/encryption/rot-13/src/Makefile

xlators/Makefile.am

@@ -1,3 +1,4 @@
-SUBDIRS = cluster storage protocol performance debug features encryption mount nfs mgmt system
+SUBDIRS = cluster storage protocol performance debug features encryption mount nfs mgmt system \
+          playground
 
 CLEANFILES =

xlators/playground/Makefile.am

@@ -0,0 +1,2 @@
+SUBDIRS = template
+CLEANFILES =

xlators/playground/template/Makefile.am

@@ -0,0 +1,2 @@
+SUBDIRS = src
+

xlators/playground/template/src/Makefile.am

@@ -0,0 +1,16 @@
+xlator_LTLIBRARIES = template.la
+xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/testing/features
+
+template_la_LDFLAGS = -module -avoid-version
+
+template_la_SOURCES = template.c
+template_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+
+noinst_HEADERS = template.h
+
+AM_CPPFLAGS = $(GF_CPPFLAGS) -I$(top_srcdir)/libglusterfs/src
+
+AM_CFLAGS = -Wall $(GF_CFLAGS)
+
+CLEANFILES =
+

xlators/playground/template/src/template.c

@@ -0,0 +1,49 @@
+/*
+   Copyright (c) 2006-2012 Red Hat, Inc. <http://www.redhat.com>
+   This file is part of GlusterFS.
+
+   This file is licensed to you under your choice of the GNU Lesser
+   General Public License, version 3 or any later version (LGPLv3 or
+   later), or the GNU General Public License, version 2 (GPLv2), in all
+   cases as published by the Free Software Foundation.
+*/
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "template.h"
+
+int32_t
+init (xlator_t *this)
+{
+
+        if (!this->children || this->children->next) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "not configured with exactly one child. exiting");
+                return -1;
+        }
+
+        if (!this->parents) {
+                gf_log (this->name, GF_LOG_WARNING,
+                        "dangling volume. check volfile ");
+        }
+
+        return 0;
+}
+
+void
+fini (xlator_t *this)
+{
+        return;
+}
+
+struct xlator_fops fops = {
+};
+
+struct xlator_cbks cbks = {
+};
+
+struct volume_options options[] = {
+        { .key  = {NULL} },
+};

xlators/playground/template/src/template.h

@@ -0,0 +1,24 @@
+/*
+   Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com>
+   This file is part of GlusterFS.
+
+   This file is licensed to you under your choice of the GNU Lesser
+   General Public License, version 3 or any later version (LGPLv3 or
+   later), or the GNU General Public License, version 2 (GPLv2), in all
+   cases as published by the Free Software Foundation.
+*/
+#ifndef __TEMPLATE_H__
+#define __TEMPLATE_H__
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glusterfs.h"
+#include "logging.h"
+#include "dict.h"
+#include "xlator.h"
+#include "defaults.h"
+
+#endif /* __TEMPLATE_H__ */