From 1ac21ab7eabedfd18e700f9140f4128412cbe0ca Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Tue, 13 Apr 2021 16:12:17 +0200
Subject: [PATCH] util: xml: Introduce virXMLFormatElementEmpty

Add a helper which will format an XML element with attributes and
children, but compared to virXMLFormatElement it also formats an empty
element if both buffers are empty.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Tested-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/libvirt_private.syms |  1 +
 src/util/virxml.c        | 42 ++++++++++++++++++++++++++--------------
 src/util/virxml.h        |  7 +++++++
 3 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 8f8d399d88..9f761c2c00 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3541,6 +3541,7 @@ virXMLBufferCreate;
 virXMLCheckIllegalChars;
 virXMLExtractNamespaceXML;
 virXMLFormatElement;
+virXMLFormatElementEmpty;
 virXMLNewNode;
 virXMLNodeContentString;
 virXMLNodeNameEqual;
diff --git a/src/util/virxml.c b/src/util/virxml.c
index 01c0114072..7cc73ab9a0 100644
--- a/src/util/virxml.c
+++ b/src/util/virxml.c
@@ -1631,6 +1631,32 @@ virXMLValidatorFree(virXMLValidator *validator)
 }
 
 
+/* same as virXMLFormatElement but outputs an empty element if @attrBuf and
+ * @childBuf are both empty */
+void
+virXMLFormatElementEmpty(virBuffer *buf,
+                         const char *name,
+                         virBuffer *attrBuf,
+                         virBuffer *childBuf)
+{
+    virBufferAsprintf(buf, "<%s", name);
+
+    if (attrBuf && virBufferUse(attrBuf) > 0)
+        virBufferAddBuffer(buf, attrBuf);
+
+    if (childBuf && virBufferUse(childBuf) > 0) {
+        virBufferAddLit(buf, ">\n");
+        virBufferAddBuffer(buf, childBuf);
+        virBufferAsprintf(buf, "</%s>\n", name);
+    } else {
+        virBufferAddLit(buf, "/>\n");
+    }
+
+    virBufferFreeAndReset(attrBuf);
+    virBufferFreeAndReset(childBuf);
+}
+
+
 /**
  * virXMLFormatElement
  * @buf: the parent buffer where the element will be placed
@@ -1655,21 +1681,7 @@ virXMLFormatElement(virBuffer *buf,
         (!childBuf || virBufferUse(childBuf) == 0))
         return;
 
-    virBufferAsprintf(buf, "<%s", name);
-
-    if (attrBuf && virBufferUse(attrBuf) > 0)
-        virBufferAddBuffer(buf, attrBuf);
-
-    if (childBuf && virBufferUse(childBuf) > 0) {
-        virBufferAddLit(buf, ">\n");
-        virBufferAddBuffer(buf, childBuf);
-        virBufferAsprintf(buf, "</%s>\n", name);
-    } else {
-        virBufferAddLit(buf, "/>\n");
-    }
-
-    virBufferFreeAndReset(attrBuf);
-    virBufferFreeAndReset(childBuf);
+    virXMLFormatElementEmpty(buf, name, attrBuf, childBuf);
 }
 
 
diff --git a/src/util/virxml.h b/src/util/virxml.h
index 13c543fbb6..eb92fbf94e 100644
--- a/src/util/virxml.h
+++ b/src/util/virxml.h
@@ -315,6 +315,13 @@ virXMLFormatElement(virBuffer *buf,
                     virBuffer *attrBuf,
                     virBuffer *childBuf);
 
+void
+virXMLFormatElementEmpty(virBuffer *buf,
+                         const char *name,
+                         virBuffer *attrBuf,
+                         virBuffer *childBuf);
+
+
 struct _virXPathContextNodeSave {
     xmlXPathContextPtr ctxt;
     xmlNodePtr node;