[libvirt PATCH v5 0/8] Refactor XML parsing boilerplate code

This series lays the groundwork for replacing some recurring boilerplate code in src/conf/ regarding the extraction of XML attribute values. For an on / off attribute, the boilerplate code looks roughly like this, g_autofree char *str = NULL; if (str = virXMLPropString(node, "x")) { int val; if ((val = virTristateBoolTypeFromString(str)) <= 0) { virReportError(...) return -1; } def->x = val; } with some variations regarding how `str` is free'd in case of later re-use, the exact error message for invalid values, whether or not `VIR_TRISTATE_(SWITCH|BOOL)_ABSENT` is explicitly checked for (`val < 0` vs. `val <= 0`), whether an intermediate variable is used or the value is assigned directly, and in some cases the conditions in the two if-blocks are merged. After the refactoring, the above code block looks like this: if (virXMLPropTristateBool(node, "x", VIR_XML_PROP_OPTIONAL, &def->x) < 0) return -1; Similar functions are introduced for integer valued attributes, unsigned integer valued attributes and enum valued attributes. Patches #6, #7, and #8 demonstrate the application of these function and stand representative of more patches that I did not sent along yet as to not drown the mailing list in spam. These patches remove a total of ~ 1000 lines of code and fix some places, where e.g. `<foo bar="default"/>` would incorrectly be accepted as virXMLTristateBool. As an added benefit, this refactoring makes the error messages for invalid values in these XML attributes much more consistent: $ git diff master | grep "^-.*_(\"" | wc -l 239 $ git diff master | grep "^+.*_(\"" | wc -l 21 V1: https://listman.redhat.com/archives/libvir-list/2021-March/msg00853.html V2: https://listman.redhat.com/archives/libvir-list/2021-March/msg00994.html V3: https://listman.redhat.com/archives/libvir-list/2021-March/msg01066.html V4: https://listman.redhat.com/archives/libvir-list/2021-April/msg00209.html Changes since V4: * Added custom error message for virXMLProp(Int|UInt) when the attribute value is 0 and VIR_XML_PROP_NONZERO is specified. Cheers, Tim Tim Wiederhake (8): virxml: Add virXMLPropTristateBool virxml: Add virXMLPropTristateSwitch virxml: Add virXMLPropInt virxml: Add virXMLPropUInt virxml: Add virXMLPropEnum virNetworkForwardNatDefParseXML: Use virXMLProp* virDomainIOThreadIDDefParseXML: Use virXMLProp* virCPUDefParseXML: Use virXMLProp* src/conf/cpu_conf.c | 14 +- src/conf/domain_conf.c | 14 +- src/conf/network_conf.c | 16 +-- src/libvirt_private.syms | 5 + src/util/virxml.c | 267 +++++++++++++++++++++++++++++++++++++++ src/util/virxml.h | 31 +++++ 6 files changed, 312 insertions(+), 35 deletions(-) -- 2.26.2