From 2bf520bf28d34e4d2336ba96525e63ae22bc21fd Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Wed, 1 Dec 2010 19:56:44 -0800
Subject: [PATCH] add new cpv_sort_key() function

---
 .../tests/versions/test_cpv_sort_key.py       | 16 +++++++
 pym/portage/versions.py                       | 44 ++++++++++++++++++-
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 pym/portage/tests/versions/test_cpv_sort_key.py

diff --git a/pym/portage/tests/versions/test_cpv_sort_key.py b/pym/portage/tests/versions/test_cpv_sort_key.py
new file mode 100644
index 000000000..857af1701
--- /dev/null
+++ b/pym/portage/tests/versions/test_cpv_sort_key.py
@@ -0,0 +1,16 @@
+# Copyright 2010 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+from portage.tests import TestCase
+from portage.versions import cpv_sort_key
+
+class CpvSortKeyTestCase(TestCase):
+
+	def testCpvSortKey(self):
+
+		tests = [ (( "a", "b", "a/b-2", "a/a-1", "a/b-1"),
+			( "a", "a/a-1", "a/b-1", "a/b-2", "b")),
+		]
+
+		for test in tests:
+			self.assertEqual( tuple(sorted(test[0], key=cpv_sort_key())), test[1] )
diff --git a/pym/portage/versions.py b/pym/portage/versions.py
index 8ac32eb24..d3271a762 100644
--- a/pym/portage/versions.py
+++ b/pym/portage/versions.py
@@ -4,13 +4,17 @@
 
 __all__ = [
 	'best', 'catpkgsplit', 'catsplit',
-	'cpv_getkey', 'cpv_getversion', 'pkgcmp',  'pkgsplit',
+	'cpv_getkey', 'cpv_getversion', 'cpv_sort_key', 'pkgcmp',  'pkgsplit',
 	'ververify', 'vercmp'
 ]
 
 import re
 import warnings
 
+import portage
+portage.proxy.lazyimport.lazyimport(globals(),
+	'portage.util:cmp_sort_key'
+)
 from portage.localization import _
 
 # \w is [a-zA-Z0-9_]
@@ -342,6 +346,44 @@ def cpv_getversion(mycpv):
 		return None
 	return mycpv[len(cp+"-"):]
 
+def cpv_sort_key():
+	"""
+	Create an object for sorting cpvs, to be useed as the 'key' parameter
+	in places like list.sort() or sorted(). This calls catpkgsplit() once for
+	each cpv and caches the result. If a given cpv is invalid or two cpvs
+	have different category/package names, then plain string (> and <)
+	comparison is used.
+
+	@rtype: key object for sorting
+	@return: object for use as the 'key' parameter in places like
+		list.sort() or sorted()
+	"""
+
+	split_cache = {}
+
+	def cmp_cpv(cpv1, cpv2):
+
+		split1 = split_cache.get(cpv1, False)
+		if split1 is False:
+			split1 = catpkgsplit(cpv1)
+			if split1 is not None:
+				split1 = (split1[:2], '-'.join(split1[2:]))
+			split_cache[cpv1] = split1
+
+		split2 = split_cache.get(cpv2, False)
+		if split2 is False:
+			split2 = catpkgsplit(cpv2)
+			if split2 is not None:
+				split2 = (split2[:2], '-'.join(split2[2:]))
+			split_cache[cpv2] = split2
+
+		if split1 is None or split2 is None or split1[0] != split2[0]:
+			return (cpv1 > cpv2) - (cpv1 < cpv2)
+
+		return vercmp(split1[1], split2[1])
+
+	return cmp_sort_key(cmp_cpv)
+
 def catsplit(mydep):
         return mydep.split("/", 1)
 
-- 
2.26.2