urldetect: Split out treeinfo logic from GenericTreeInfo

SUSE distros will be growing treeinfo support soon and trying to handle
this logic through class inheritance is difficult, so separate the
logic into its own function

virtinst/urldetect.py

@@ -89,6 +89,34 @@ class _DistroCache(object):
                 filename, regex)
         return False
 
+    def get_treeinfo_media(self, typ):
+        """
+        Pull kernel/initrd/boot.iso paths out of the treeinfo for
+        the passed data
+        """
+        def _get_treeinfo_path(media_name):
+            image_type = self.treeinfo.get("general", "arch")
+            if typ == "xen":
+                image_type = "xen"
+            return self.treeinfo.get("images-%s" % image_type, media_name)
+
+        kernel_paths = []
+        boot_iso_paths = []
+
+        try:
+            kernel_paths.append(
+                (_get_treeinfo_path("kernel"), _get_treeinfo_path("initrd")))
+        except Exception:
+            logging.debug("Failed to parse treeinfo kernel/initrd",
+                    exc_info=True)
+
+        try:
+            boot_iso_paths.append(_get_treeinfo_path("boot.iso"))
+        except Exception:
+            logging.debug("Failed to parse treeinfo boot.iso", exc_info=True)
+
+        return kernel_paths, boot_iso_paths
+
 
 class _SUSEContent(object):
     """
@@ -332,41 +360,20 @@ class Distro(object):
         return None
 
 
-class GenericTreeinfoDistro(Distro):
-    PRETTY_NAME = "Generic Treeinfo"
-    urldistro = None
+class RedHatDistro(Distro):
+    """
+    Baseclass for Red Hat based distros
+    """
+    @classmethod
+    def is_valid(cls, cache):
+        raise NotImplementedError
 
     def __init__(self, *args, **kwargs):
         Distro.__init__(self, *args, **kwargs)
 
-        if not self.cache.treeinfo:
-            return
-
-        self._kernel_paths = []
-        self._boot_iso_paths = []
-
-        try:
-            self._kernel_paths.append(
-                (self._getTreeinfoMedia("kernel"),
-                 self._getTreeinfoMedia("initrd")))
-        except Exception:
-            logging.debug("Failed to parse treeinfo kernel/initrd",
-                    exc_info=True)
-
-        try:
-            self._boot_iso_paths.append(self._getTreeinfoMedia("boot.iso"))
-        except Exception:
-            logging.debug("Failed to parse treeinfo boot.iso", exc_info=True)
-
-    def _getTreeinfoMedia(self, mediaName):
-        image_type = self.cache.treeinfo.get("general", "arch")
-        if self.type == "xen":
-            image_type = "xen"
-        return self.cache.treeinfo.get("images-%s" % image_type, mediaName)
-
-    @classmethod
-    def is_valid(cls, cache):
-        return bool(cache.treeinfo)
+        k, b = self.cache.get_treeinfo_media(self.type)
+        self._kernel_paths = k
+        self._boot_iso_paths = b
 
     def _get_kernel_url_arg(self):
         def _is_old_rhdistro():
@@ -388,7 +395,7 @@ class GenericTreeinfoDistro(Distro):
         return "inst.repo"
 
 
-class FedoraDistro(GenericTreeinfoDistro):
+class FedoraDistro(RedHatDistro):
     PRETTY_NAME = "Fedora"
     urldistro = "fedora"
 
@@ -422,7 +429,7 @@ class FedoraDistro(GenericTreeinfoDistro):
         return latest_variant
 
 
-class RHELDistro(GenericTreeinfoDistro):
+class RHELDistro(RedHatDistro):
     PRETTY_NAME = "Red Hat Enterprise Linux"
     urldistro = "rhel"
     _variant_prefix = "rhel"
@@ -787,6 +794,25 @@ class MandrivaDistro(Distro):
             ("isolinux/alt0/vmlinuz", "isolinux/alt0/all.rdz")]
 
 
+class GenericTreeinfoDistro(Distro):
+    """
+    Generic catchall class for .treeinfo using distros
+    """
+    PRETTY_NAME = "Generic Treeinfo"
+    urldistro = None
+
+    @classmethod
+    def is_valid(cls, cache):
+        return bool(cache.treeinfo)
+
+    def __init__(self, *args, **kwargs):
+        Distro.__init__(self, *args, **kwargs)
+
+        k, b = self.cache.get_treeinfo_media(self.type)
+        self._kernel_paths = k
+        self._boot_iso_paths = b
+
+
 # Build list of all *Distro classes
 def _build_distro_list():
     allstores = []