ubuntutools.distro_info: Add a function to find the distribution that

used a given release codename.

debian/changelog

@@ -26,8 +26,10 @@ ubuntu-dev-tools (0.125) UNRELEASED; urgency=low
   * ubuntutools.misc: Add a new "system_distribution_chain", which returns
     a list starting with the current distribution and working its way up
     each distribution's parent.
+  * ubuntutools.distro_info: Add a function to find the distribution that
+    used a given release codename.
 
- -- Evan Broder <evan@ebroder.net>  Sat, 11 Jun 2011 05:05:21 -0700
+ -- Evan Broder <evan@ebroder.net>  Sat, 11 Jun 2011 05:06:44 -0700
 
 ubuntu-dev-tools (0.124) unstable; urgency=low
 

ubuntutools/distro_info.py

@@ -18,6 +18,8 @@ import csv
 import datetime
 import os
 
+from ubuntutools.misc import system_distribution_chain
+
 def convert_date(string):
     """Convert a date string in ISO 8601 into a datetime object."""
     if not string:
@@ -195,3 +197,29 @@ class UbuntuDistroInfo(DistroInfo):
                    if date <= x["eol"] or
                       (x["eol-server"] is not None and date <= x["eol-server"])]
         return distros
+
+_vendor_to_distroinfo = {"Debian": DebianDistroInfo,
+                         "Ubuntu": UbuntuDistroInfo}
+def vendor_to_distroinfo(vendor):
+    """ vendor_to_distroinfo(string) -> DistroInfo class
+
+    Convert a string name of a distribution into a DistroInfo subclass
+    representing that distribution, or None if the distribution is
+    unknown.
+    """
+    return _vendor_to_distroinfo.get(vendor)
+
+def codename_to_distribution(codename):
+    """ codename_to_distribution(string) -> string
+
+    Finds a given release codename in your distribution's genaology
+    (i.e. looking at the current distribution and its parents), or
+    print an error message and return None if it can't be found
+    """
+    for distro in system_distribution_chain():
+        info = vendor_to_distroinfo(distro)
+        if not info:
+            continue
+
+        if codename in info().all:
+            return distro