xmlbuilder: Simplify global XML vars

Just have classes specify a root XML path, and figure out root name,
indentation, and dumpxml path from there.

virtinst/CPU.py

@@ -27,9 +27,8 @@ class CPUFeature(XMLBuilder):
 
     POLICIES = ["force", "require", "optional", "disable", "forbid"]
 
+    _XML_ROOT_XPATH = "/domain/cpu/feature"
     _XML_PROP_ORDER = ["_xmlname", "policy"]
-    _XML_ROOT_NAME = "cpu"
-    _XML_INDENT = 4
 
     def __init__(self, conn, name, parsexml=None, parsexmlnode=None):
         XMLBuilder.__init__(self, conn, parsexml, parsexmlnode)
@@ -60,9 +59,7 @@ class CPU(XMLBuilder):
 
     MATCHS = ["minimum", "exact", "strict"]
 
-    _dumpxml_xpath = "/domain/cpu"
+    _XML_ROOT_XPATH = "/domain/cpu"
-    _XML_ROOT_NAME = "cpu"
-    _XML_INDENT = 2
     _XML_PROP_ORDER = ["mode", "match", "model", "vendor",
                        "sockets", "cores", "threads", "_features"]
 

virtinst/Clock.py

@@ -21,8 +21,6 @@ from virtinst.xmlbuilder import XMLBuilder, XMLProperty
 
 
 class Clock(XMLBuilder):
-    _dumpxml_xpath = "/domain/clock"
+    _XML_ROOT_XPATH = "/domain/clock"
-    _XML_INDENT = 2
-    _XML_ROOT_NAME = "clock"
 
     offset = XMLProperty(xpath="./clock/@offset")

virtinst/DomainFeatures.py

@@ -24,9 +24,7 @@ class DomainFeatures(XMLBuilder):
     """
     Class for generating <features> XML
     """
-    _dumpxml_xpath = "/domain/features"
+    _XML_ROOT_XPATH = "/domain/features"
-    _XML_ROOT_NAME = "features"
-    _XML_INDENT = 2
     _XML_PROP_ORDER = ["acpi", "apic", "pae"]
 
     acpi = XMLProperty(xpath="./features/acpi", is_tri=True)

virtinst/DomainNumatune.py

@@ -95,9 +95,7 @@ class DomainNumatune(XMLBuilder):
 
     MEMORY_MODES = ["interleave", "strict", "preferred"]
 
-    _dumpxml_xpath = "/domain/numatune"
+    _XML_ROOT_XPATH = "/domain/numatune"
-    _XML_ROOT_NAME = "numatune"
-    _XML_INDENT = 2
     _XML_PROP_ORDER = ["memory_mode", "memory_nodeset"]
 
     memory_nodeset = XMLProperty(xpath="./numatune/memory/@nodeset")

virtinst/Guest.py

@@ -161,8 +161,7 @@ class Guest(XMLBuilder):
         return cpustr
 
 
-    _XML_ROOT_NAME = "domain"
+    _XML_ROOT_XPATH = "/domain"
-    _XML_INDENT = 0
     _XML_PROP_ORDER = ["type", "name", "uuid", "description",
         "maxmemory", "memory", "hugepage", "vcpus", "curvcpus",
         "numatune", "bootloader", "os", "features", "cpu", "clock",

virtinst/Seclabel.py

@@ -38,9 +38,7 @@ class Seclabel(XMLBuilder):
     MODEL_NONE = "none"
     MODELS = [MODEL_SELINUX, MODEL_DAC, MODEL_NONE]
 
-    _dumpxml_xpath = "/domain/seclabel"
+    _XML_ROOT_XPATH = "/domain/seclabel"
-    _XML_ROOT_NAME = "seclabel"
-    _XML_INDENT = 2
     _XML_PROP_ORDER = ["type", "model", "relabel", "label", "imagelabel"]
 
     def _guess_secmodel(self):

virtinst/VirtualDevice.py

@@ -75,7 +75,6 @@ class VirtualDevice(XMLBuilder):
 
     # General device type (disk, interface, etc.)
     virtual_device_type = None
-    _XML_INDENT = 4
 
     def __init__(self, conn, parsexml=None, parsexmlnode=None):
         """
@@ -83,8 +82,9 @@ class VirtualDevice(XMLBuilder):
 
         @param conn: libvirt connection to validate device against
         """
+        self._XML_ROOT_XPATH = "/domain/devices/%s" % self.virtual_device_type
+
         XMLBuilder.__init__(self, conn, parsexml, parsexmlnode)
-        self._XML_ROOT_NAME = self.virtual_device_type
 
         self.alias = VirtualDeviceAlias(conn, parsexmlnode=parsexmlnode)
         self.address = VirtualDeviceAddress(conn, parsexmlnode=parsexmlnode)
@@ -111,9 +111,7 @@ class VirtualDevice(XMLBuilder):
 
 
 class VirtualDeviceAlias(XMLBuilder):
-    _XML_ROOT_NAME = "alias"
+    _XML_ROOT_XPATH = "/domain/devices/device/alias"
-    _XML_INDENT = 0
-
     name = XMLProperty(xpath="./alias/@name")
 
 
@@ -136,8 +134,7 @@ class VirtualDeviceAddress(XMLBuilder):
              ADDRESS_TYPE_VIRTIO_SERIAL, ADDRESS_TYPE_CCID,
              ADDRESS_TYPE_SPAPR_VIO]
 
-    _XML_ROOT_NAME = "address"
+    _XML_ROOT_XPATH = "/domain/devices/device/address"
-    _XML_INDENT = 0
     _XML_PROP_ORDER = ["type", "domain", "bus", "slot", "function"]
 
     def set_addrstr(self, addrstr):

virtinst/VirtualNetworkInterface.py

@@ -53,6 +53,8 @@ def _random_mac(conn):
 
 
 class VirtualPort(XMLBuilder):
+    _XML_ROOT_XPATH = "/domain/devices/interface/virtualport"
+
     type = XMLProperty(xpath="./virtualport/@type")
     managerid = XMLProperty(xpath="./virtualport/parameters/@managerid",
                             is_int=True)

virtinst/osxml.py

@@ -39,15 +39,11 @@ class OSXML(XMLBuilder):
     def is_container(self):
         return self.os_type == "exe"
 
-    _dumpxml_xpath = "/domain/os"
+    _XML_ROOT_XPATH = "/domain/os"
-    _XML_ROOT_NAME = "os"
-    _XML_INDENT = 2
     _XML_PROP_ORDER = ["arch", "os_type", "loader",
                        "kernel", "initrd", "kernel_args",
                        "bootorder"]
 
-    type = property(lambda s: s.snarf)
-
     enable_bootmenu = XMLProperty(xpath="./os/bootmenu/@enable", is_yesno=True)
     bootorder = XMLProperty(xpath="./os/boot/@dev", is_multi=True)
 

virtinst/xmlbuilder.py

@@ -574,14 +574,8 @@ class XMLBuilder(object):
     # consistent with what the test suite expects.
     _XML_PROP_ORDER = []
 
-    # Root element name of this function, used to populate a default
+    # Absolute xpath this object is rooted at
-    # _get_xml_config
+    _XML_ROOT_XPATH = None
-    _XML_ROOT_NAME = None
-
-    # Integer indentation level for generated XML.
-    _XML_INDENT = None
-
-    _dumpxml_xpath = "."
 
     def __init__(self, conn, parsexml=None, parsexmlnode=None):
         """
@@ -595,7 +589,15 @@ class XMLBuilder(object):
         """
         self.conn = conn
 
+        xpath = self._XML_ROOT_XPATH
+        if xpath is None or not xpath.startswith("/"):
+            raise RuntimeError("xpath=%s must start with /" % xpath)
+
+        self._xml_root_name = xpath.split("/")[-1]
+        self._xml_indent = (xpath.count("/") - 1) * 2
+        self._xml_dump_xpath = xpath
         self._xml_root_xpath = ""
+
         self._xml_node = None
         self._xml_ctx = None
         self._xml_root_doc = None
@@ -640,7 +642,7 @@ class XMLBuilder(object):
     def get_xml_config(self):
         data = self._prepare_get_xml()
         try:
-            return self._do_get_xml_config(self._dumpxml_xpath)
+            return self._do_get_xml_config()
         finally:
             self._finish_get_xml(data)
 
@@ -648,7 +650,7 @@ class XMLBuilder(object):
         for prop in self.all_xml_props().values():
             prop._clear(self)
 
-    def _do_get_xml_config(self, dumpxml_xpath):
+    def _do_get_xml_config(self):
         """
         Construct and return object xml
 
@@ -656,22 +658,21 @@ class XMLBuilder(object):
         @rtype: str
         """
         if self._xml_ctx:
-            node = _get_xpath_node(self._xml_ctx, dumpxml_xpath)
+            node = _get_xpath_node(self._xml_ctx, self._xml_dump_xpath)
             if not node:
                 ret = ""
             else:
                 ret = _sanitize_libxml_xml(node.serialize())
         else:
-            xmlstub = self._make_xml_stub(fail=False)
+            xmlstub = self._make_xml_stub()
-            ret = self._make_xml_stub(fail=True)
+            if xmlstub is None:
-            if ret is None:
                 return None
 
-            ret = self._add_parse_bits(ret)
+            ret = self._add_parse_bits(xmlstub)
             if ret == xmlstub:
                 ret = ""
 
-        if self._XML_ROOT_NAME == "domain" and not ret.endswith("\n"):
+        if ret and self._xml_root_name == "domain" and not ret.endswith("\n"):
             ret += "\n"
         return ret
 
@@ -704,18 +705,8 @@ class XMLBuilder(object):
     # Internal XML parsers #
     ########################
 
-    def _make_xml_stub(self, fail=True):
+    def _make_xml_stub(self):
-        if self._XML_ROOT_NAME is None:
+        return _indent("<%s/>" % (self._xml_root_name), self._xml_indent)
-            if not fail:
-                return None
-            raise RuntimeError("Must specify _XML_ROOT_NAME.")
-        if self._XML_INDENT is None:
-            if not fail:
-                return None
-            raise RuntimeError("Must specify _XML_INDENT.")
-        if self._XML_ROOT_NAME == "":
-            return ""
-        return _indent("<%s/>" % (self._XML_ROOT_NAME), self._XML_INDENT)
 
     def _add_child(self, parent_xpath, dev):
         """
@@ -742,6 +733,7 @@ class XMLBuilder(object):
             doc = libxml2.parseDoc(xml)
             self._xml_root_doc = _DocCleanupWrapper(doc)
             self._xml_node = doc.children
+            self._xml_dump_xpath = "."
 
             # This just stores a reference to our root doc wrapper in
             # the root node, so when the node goes away it triggers
@@ -749,6 +741,7 @@ class XMLBuilder(object):
             self._xml_node.virtinst_root_doc = self._xml_root_doc
         else:
             self._xml_node = node
+            self._xml_dump_xpath = self._XML_ROOT_XPATH
 
         self._set_xml_context()
 
@@ -804,8 +797,7 @@ class XMLBuilder(object):
                         obj._xml_root_xpath = self._xml_root_xpath
                     obj._add_parse_bits(xml=None, node=self._xml_node)
 
-        xml = self._do_get_xml_config(".").strip("\n")
+        return _indent(self._do_get_xml_config(), indent)
-        return _indent(xml, indent)
 
     def _add_parse_bits(self, xml, node=None):
         """