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@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 */