On Tue, Feb 26, 2019 at 18:08:11 +0100, Peter Krempa wrote:
Quite a few parts modify the XPath context current node to shif the
scope and allow easier queries. This also means that the node needs
to be restored afterwards.
Introduce a macro based on 'VIR_AUTOCLEAN' which adds a local structure
on the stack remembering the original node along with a function which
will make sure that the node is reset when the local structure leaves
scope.
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
src/libvirt_private.syms | 1 +
src/util/virxml.c | 10 ++++++++++
src/util/virxml.h | 22 ++++++++++++++++++++++
3 files changed, 33 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 038a744981..ee5d9957b0 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3246,6 +3246,7 @@ virXMLValidatorFree;
virXMLValidatorInit;
virXMLValidatorValidate;
virXPathBoolean;
+virXPathContextNodeRestore;
virXPathInt;
virXPathLong;
virXPathLongHex;
diff --git a/src/util/virxml.c b/src/util/virxml.c
index 8eb201fddf..f55b9a362c 100644
--- a/src/util/virxml.c
+++ b/src/util/virxml.c
@@ -1398,3 +1398,13 @@ virXMLFormatElement(virBufferPtr buf,
virBufferFreeAndReset(childBuf);
return ret;
}
+
+
+void
+virXPathContextNodeRestore(virXPathContextNodeSavePtr save)
+{
+ if (!save->ctxt)
+ return;
+
+ save->ctxt->node = save->node;
+}
diff --git a/src/util/virxml.h b/src/util/virxml.h
index 23a4da1b7e..1bd2c0e518 100644
--- a/src/util/virxml.h
+++ b/src/util/virxml.h
@@ -219,4 +219,26 @@ virXMLFormatElement(virBufferPtr buf,
virBufferPtr attrBuf,
virBufferPtr childBuf);
+struct _virXPathContextNodeSave {
+ xmlXPathContextPtr ctxt;
+ xmlNodePtr node;
+};
+typedef struct _virXPathContextNodeSave virXPathContextNodeSave;
+typedef virXPathContextNodeSave *virXPathContextNodeSavePtr;
+
+void
+virXPathContextNodeRestore(virXPathContextNodeSavePtr save);
+
+VIR_DEFINE_AUTOCLEAN_FUNC(virXPathContextNodeSave, virXPathContextNodeRestore);
+
+/**
+ * VIR_XPATH_NODE_AUTORESTORE:
+ * @ctxt: XML XPath context pointer
+ *
+ * This macro ensures that when the scope where it's used ends @ctxt's current
+ * node pointer is reset to the original value when this macro was used.
+ */
+# define VIR_XPATH_NODE_AUTORESTORE(ctxt) \
+ VIR_AUTOCLEAN(virXPathContextNodeSave) ctxt ## CtxtSave = {(ctxt), (ctxt)->node}
Oops, forgot to commit some local changes:
diff --git a/src/util/virxml.h b/src/util/virxml.h
index 1bd2c0e518..72b9d749d0 100644
--- a/src/util/virxml.h
+++ b/src/util/virxml.h
@@ -239,6 +239,7 @@ VIR_DEFINE_AUTOCLEAN_FUNC(virXPathContextNodeSave,
virXPathContextNodeRestore);
* node pointer is reset to the original value when this macro was used.
*/
# define VIR_XPATH_NODE_AUTORESTORE(ctxt) \
- VIR_AUTOCLEAN(virXPathContextNodeSave) ctxt ## CtxtSave = {(ctxt), (ctxt)->node}
+ VIR_AUTOCLEAN(virXPathContextNodeSave) ctxt##CtxtSave = {ctxt, ctxt->node}; \
+ ignore_value(&ctxt##CtxtSave)
#endif /* LIBVIRT_VIRXML_H */