From: Michal Privoznik <mprivozn@redhat.com>

Similarly to other virXPath* functions, let's have a helper that
evaluates an XPath and stores the value into virTristateSwitch.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/libvirt_private.syms |  1 +
 src/util/virxml.c        | 34 ++++++++++++++++++++++++++++++++++
 src/util/virxml.h        |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 7986ad123c..0b692c038e 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3827,6 +3827,7 @@ virXPathLongLong;
 virXPathNode;
 virXPathNodeSet;
 virXPathString;
+virXPathTristateSwitch;
 virXPathUInt;
 virXPathUIntBase;
 virXPathULongLong;
diff --git a/src/util/virxml.c b/src/util/virxml.c
index bb80bb7444..60485c10fa 100644
--- a/src/util/virxml.c
+++ b/src/util/virxml.c
@@ -284,6 +284,40 @@ virXPathLongLong(const char *xpath,
 }
 
 
+/**
+ * virXPathTristateSwitch:
+ * @xpath: the XPath string to evaluate
+ * @ctxt: an XPath context
+ * @value: the returned virTristateSwitch value
+ *
+ * Convenience function to evaluate an XPath tristate value. The @xpath
+ * expression must ensure that the evaluated value is returned as a
+ * string (use the 'string()' conversion in the expression).
+ *
+ * Returns 0 in case of success in which case @value is set,
+ *         or -1 if the XPath evaluation failed or -2 if the
+ *         value isn't of a virTristateSwitch value.
+ */
+int
+virXPathTristateSwitch(const char *xpath,
+                       xmlXPathContextPtr ctxt,
+                       virTristateSwitch *value)
+{
+    g_autoptr(xmlXPathObject) obj = NULL;
+    int rc;
+
+    if (!(obj = virXPathEvalString(xpath, ctxt)))
+        return -1;
+
+    rc = virTristateSwitchTypeFromString((char *)obj->stringval);
+    if (rc < 0)
+        return -2;
+
+    *value = rc;
+    return 0;
+}
+
+
 /**
  * virXMLCheckIllegalChars:
  * @nodeName: Name of checked node
diff --git a/src/util/virxml.h b/src/util/virxml.h
index 7cc3f47913..dfec386494 100644
--- a/src/util/virxml.h
+++ b/src/util/virxml.h
@@ -73,6 +73,11 @@ virXPathLongLong(const char *xpath,
                  xmlXPathContextPtr ctxt,
                  long long *value);
 
+int
+virXPathTristateSwitch(const char *xpath,
+                       xmlXPathContextPtr ctxt,
+                       virTristateSwitch *value);
+
 xmlNodePtr
 virXMLNodeGetSubelement(xmlNodePtr node,
                         const char *name);
-- 
2.49.1