Add: Image class

3 files changed, 156 insertions, 0 deletions

diff --git a/vmdb/__init__.py b/vmdb/__init__.py
index 7a2c584..0163b53 100644
--- a/vmdb/__init__.py
+++ b/vmdb/__init__.py
@@ -31,6 +31,7 @@ from .runcmd import (
     progress,
     error,
 )
+from .image import Image, UnknownTag, TagInUse, AlreadyMounted
 from .unmount import unmount, NotMounted
 from .spec import (
     Spec,
diff --git a/vmdb/image.py b/vmdb/image.py
new file mode 100644
index 0000000..67c39de
--- /dev/null
+++ b/vmdb/image.py
@@ -0,0 +1,83 @@
+# Copyright 2018  Lars Wirzenius
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# =*= License: GPL-3+ =*=
+
+
+# Unmount a directory, including any mount points under that
+# directory. If /mnt/foo is given, and /mnt/foo/bar is also mounted,
+# unmount /mnt/foo/bar first, and /mnt/foo then. Look for sub-mounts
+# in /proc/mounts.
+
+
+import vmdb
+
+
+class Image:
+
+    def __init__(self):
+        self._tags = {}
+
+    def get_tags(self):
+        return list(self._tags.keys())
+
+    def get_dev(self, tag):
+        item = self._tags.get(tag)
+        if item is None:
+            raise UnknownTag(tag)
+        return item['dev']
+
+    def get_mount_point(self, tag):
+        item = self._tags.get(tag)
+        if item is None:
+            raise UnknownTag(tag)
+        return item['mount_point']
+
+    def add_partition(self, tag, dev):
+        if tag in self._tags:
+            raise TagInUse(tag)
+        self._new(tag, dev, None)
+
+    def add_mount_point(self, tag, mount_point):
+        item = self._tags.get(tag)
+        if item is None:
+            raise UnknownTag(tag)
+        if item['mount_point'] is not None:
+            raise AlreadyMounted(tag)
+        item['mount_point'] = mount_point
+
+    def _new(self, tag, dev, mount_point):
+        self._tags[tag] = {
+            'dev': dev,
+            'mount_point': mount_point,
+        }
+
+
+class TagInUse(Exception):
+
+    def __init__(self, tag):
+        super().__init__('Tag already used: {}'.format(tag))
+
+
+class UnknownTag(Exception):
+
+    def __init__(self, tag):
+        super().__init__('Unknown tag: {}'.format(tag))
+
+
+class AlreadyMounted(Exception):
+
+    def __init__(self, tag):
+        super().__init__('Already mounted tag: {}'.format(tag))
diff --git a/vmdb/image_tests.py b/vmdb/image_tests.py
new file mode 100644
index 0000000..e2e72db
--- /dev/null
+++ b/vmdb/image_tests.py
@@ -0,0 +1,72 @@
+# Copyright 2018  Lars Wirzenius
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# =*= License: GPL-3+ =*=
+
+
+import unittest
+
+
+import vmdb
+
+
+class ImageTests(unittest.TestCase):
+
+    def test_lists_not_tags_initally(self):
+        image = vmdb.Image()
+        self.assertEqual(image.get_tags(), [])
+
+    def test_get_dev_raises_error_for_unknown_tag(self):
+        image = vmdb.Image()
+        with self.assertRaises(vmdb.UnknownTag):
+            image.get_dev('does-not-exist')
+
+    def test_get_mount_point_raises_error_for_unknown_tag(self):
+        image = vmdb.Image()
+        with self.assertRaises(vmdb.UnknownTag):
+            image.get_mount_point('does-not-exist')
+
+    def test_raises_error_for_reused_tag(self):
+        image = vmdb.Image()
+        image.add_partition('tag', 'dev')
+        with self.assertRaises(vmdb.TagInUse):
+            image.add_partition('tag', 'dev')
+
+    def test_adds_partition(self):
+        image = vmdb.Image()
+        image.add_partition('first', '/dev/foo')
+        self.assertEqual(image.get_tags(), ['first'])
+        self.assertEqual(image.get_dev('first'), '/dev/foo')
+        self.assertEqual(image.get_mount_point('first'), None)
+
+    def test_adds_mount_point(self):
+        image = vmdb.Image()
+        image.add_partition('first', '/dev/foo')
+        image.add_mount_point('first', '/mnt/foo')
+        self.assertEqual(image.get_tags(), ['first'])
+        self.assertEqual(image.get_dev('first'), '/dev/foo')
+        self.assertEqual(image.get_mount_point('first'), '/mnt/foo')
+
+    def test_add_mount_point_raises_error_for_unknown_tag(self):
+        image = vmdb.Image()
+        with self.assertRaises(vmdb.UnknownTag):
+            image.add_mount_point('first', '/mnt/foo')
+
+    def test_add_mount_point_raises_error_for_double_mount(self):
+        image = vmdb.Image()
+        image.add_partition('first', '/dev/foo')
+        image.add_mount_point('first', '/mnt/foo')
+        with self.assertRaises(vmdb.AlreadyMounted):
+            image.add_mount_point('first', '/mnt/foo')