From a9c791b5b86b93745454a159eb6d5945fb4ae5c1 Mon Sep 17 00:00:00 2001
From: Martin Kletzander <mkletzan@redhat.com>
Date: Wed, 12 Feb 2014 15:44:40 +0100
Subject: [PATCH] Add target_to_num method

Opposite to num_to_target.  It will be used in future patch.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
 tests/xmlconfig.py     | 13 +++++++++++++
 virtinst/devicedisk.py | 16 +++++++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/tests/xmlconfig.py b/tests/xmlconfig.py
index c88573898..9db51cb4c 100644
--- a/tests/xmlconfig.py
+++ b/tests/xmlconfig.py
@@ -1027,6 +1027,16 @@ class TestXMLConfig(unittest.TestCase):
         self.assertEquals("zz", VirtualDisk.num_to_target(27 * 26))
         self.assertEquals("aaa", VirtualDisk.num_to_target(27 * 26 + 1))
 
+        self.assertEquals(VirtualDisk.target_to_num("hda"), 1)
+        self.assertEquals(VirtualDisk.target_to_num("hdb"), 2)
+        self.assertEquals(VirtualDisk.target_to_num("sdz"), 26)
+        self.assertEquals(VirtualDisk.target_to_num("sdaa"), 27)
+        self.assertEquals(VirtualDisk.target_to_num("vdab"), 28)
+        self.assertEquals(VirtualDisk.target_to_num("vdaz"), 52)
+        self.assertEquals(VirtualDisk.target_to_num("xvdba"), 53)
+        self.assertEquals(VirtualDisk.target_to_num("xvdzz"), 27 * 26)
+        self.assertEquals(VirtualDisk.target_to_num("xvdaaa"), 27 * 26 + 1)
+
         disk = virtinst.VirtualDisk(utils.get_conn())
         disk.bus = "ide"
 
@@ -1035,6 +1045,9 @@ class TestXMLConfig(unittest.TestCase):
         self.assertEquals("hdc", disk.generate_target(["hdb", "sda"]))
         self.assertEquals("hdb", disk.generate_target(["hda", "hdd"]))
 
+        disk.bus = "scsi"
+        self.assertEquals("sdh", disk.generate_target(["sda", "sdg"], 1))
+
     def testFedoraTreeinfo(self):
         i = utils.make_distro_installer(
                                 location="tests/cli-test-xml/fakefedoratree")
diff --git a/virtinst/devicedisk.py b/virtinst/devicedisk.py
index ce038dedc..e69a0e929 100644
--- a/virtinst/devicedisk.py
+++ b/virtinst/devicedisk.py
@@ -1,7 +1,7 @@
 #
 # Classes for building disk device xml
 #
-# Copyright 2006-2008, 2012-2013 Red Hat, Inc.
+# Copyright 2006-2008, 2012-2014 Red Hat, Inc.
 # Jeremy Katz <katzj@redhat.com>
 #
 # This program is free software; you can redistribute it and/or modify
@@ -474,6 +474,20 @@ class VirtualDisk(VirtualDevice):
         return gen_t
 
 
+    @staticmethod
+    def target_to_num(tgt):
+        """
+        Convert disk /dev number (like hda, hdb, hdaa, etc.) to an index
+        """
+        num = 0
+        if tgt[0] == 'x':
+            # This case is here for 'xvda'
+            tgt = tgt[1:]
+        for i, c in enumerate(reversed(tgt[2:])):
+            num += (ord(c) - ord('a') + 1) * (26 ** i)
+        return num
+
+
     _XML_PROP_ORDER = [
         "type", "device",
         "driver_name", "driver_type",