From 8d704e6cf7da60156a0b25b165d4780e99a0fa2f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A1n=20Tomko?= <jtomko@redhat.com>
Date: Mon, 22 Aug 2016 17:45:18 +0200
Subject: [PATCH] Use a separate buffer for <filesystem><driver>

Format the attributes in a separate buffer and only
print the element if it's not empty.
---
 src/conf/domain_conf.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 97f00da9d3..61006dea7d 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -21388,6 +21388,7 @@ virDomainFSDefFormat(virBufferPtr buf,
     const char *fsdriver = virDomainFSDriverTypeToString(def->fsdriver);
     const char *wrpolicy = virDomainFSWrpolicyTypeToString(def->wrpolicy);
     const char *src = def->src->path;
+    virBuffer driverBuf = VIR_BUFFER_INITIALIZER;
 
     if (!type) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -21407,16 +21408,21 @@ virDomainFSDefFormat(virBufferPtr buf,
                       type, accessmode);
     virBufferAdjustIndent(buf, 2);
     if (def->fsdriver) {
-        virBufferAsprintf(buf, "<driver type='%s'", fsdriver);
+        virBufferAsprintf(&driverBuf, " type='%s'", fsdriver);
 
         if (def->format)
-            virBufferAsprintf(buf, " format='%s'",
+            virBufferAsprintf(&driverBuf, " format='%s'",
                               virStorageFileFormatTypeToString(def->format));
 
         /* Don't generate anything if wrpolicy is set to default */
         if (def->wrpolicy)
-            virBufferAsprintf(buf, " wrpolicy='%s'", wrpolicy);
+            virBufferAsprintf(&driverBuf, " wrpolicy='%s'", wrpolicy);
 
+    }
+
+    if (virBufferUse(&driverBuf)) {
+        virBufferAddLit(buf, "<driver");
+        virBufferAddBuffer(buf, &driverBuf);
         virBufferAddLit(buf, "/>\n");
     }