storage: Use DBus directly for listing disks

Bring us closer to avoiding the use of two different methods to access UDisks
DBus API: UDisks2 client library and direct DBus access with GDBus.

Perform formatting of the bytes outside of udisks2 module to avoid depending on
Django.

Tests performed:

- Visit the storage page. Disks are listed properly.

- Sizes are formatted to be human readable.

- Filesystem type is show properly: ext4, btrfs

- Labels for disks are shown as set by tune2fs etc.

- Device paths are shown properly.

- Mount point is shown properly.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/storage/__init__.py

@@ -13,7 +13,7 @@ from django.utils.translation import ugettext_noop
 
 from plinth import actions
 from plinth import app as app_module
-from plinth import cfg, glib, menu, utils
+from plinth import cfg, glib, menu
 from plinth.errors import ActionError, PlinthError
 from plinth.utils import format_lazy, import_from_gi
 
@@ -77,50 +77,19 @@ def init():
 def get_disks():
     """Returns list of disks by combining information from df and udisks."""
     disks = _get_disks_from_df()
-    disks_from_udisks = _get_disks_from_udisks()
+    disks_from_udisks = udisks2.get_disks()
+    for disk in disks_from_udisks:
+        disk['size'] = format_bytes(disk['size'])
 
     # Add info from udisks to the disks from df based on mount point.
     for disk_from_df in disks:
         for disk_from_udisks in disks_from_udisks:
-            if disk_from_udisks['mount_point'] == disk_from_df['mount_point']:
+            if disk_from_df['mount_point'] in disk_from_udisks['mount_points']:
                 disk_from_df.update(disk_from_udisks)
 
     return sorted(disks, key=lambda disk: disk['device'])
 
 
-def _get_disks_from_udisks():
-    """List devices that can be ejected."""
-    udisks = utils.import_from_gi('UDisks', '2.0')
-    client = udisks.Client.new_sync()
-    object_manager = client.get_object_manager()
-    devices = []
-
-    for obj in object_manager.get_objects():
-
-        if not obj.get_block():
-            continue
-
-        block = obj.get_block()
-
-        if block.props.id_usage != 'filesystem':
-            continue
-
-        device = {
-            'device': block.props.device,
-            'label': block.props.id_label,
-            'size': format_bytes(block.props.size),
-            'filesystem_type': block.props.id_type,
-            'is_removable': not block.props.hint_system
-        }
-        try:
-            device['mount_point'] = obj.get_filesystem().props.mount_points[0]
-        except Exception:
-            continue
-        devices.append(device)
-
-    return devices
-
-
 def _get_disks_from_df():
     """Return the list of disks and free space available using 'df'."""
     try:

plinth/modules/storage/udisks2.py

@@ -79,7 +79,7 @@ class Proxy:
         if signature == 'aay':
             return [bytes(value_item).decode()[:-1] for value_item in value]
 
-        if signature in ('s', 'b', 'o', 'u'):
+        if signature in ('s', 'b', 'o', 'u', 't'):
             return glib.Variant.unpack(value)
 
         raise ValueError('Unhandled type')
@@ -100,7 +100,11 @@ class BlockDevice(Proxy):
         'hint_ignore': ('b', 'HintIgnore'),
         'hint_system': ('b', 'HintSystem'),
         'id': ('s', 'Id'),
+        'id_label': ('s', 'IdLabel'),
+        'id_type': ('s', 'IdType'),
+        'id_usage': ('s', 'IdUsage'),
         'preferred_device': ('ay', 'PreferredDevice'),
+        'size': ('t', 'Size'),
         'symlinks': ('aay', 'Symlinks'),
     }
 
@@ -119,6 +123,38 @@ class Filesystem(Proxy):
     properties = {'mount_points': ('aay', 'MountPoints')}
 
 
+def get_disks():
+    """List devices that can be ejected."""
+    devices = []
+
+    manager = _get_dbus_proxy(_OBJECTS['UDisks2'],
+                              _INTERFACES['ObjectManager'])
+    objects = manager.GetManagedObjects()
+    for object_, interface_and_properties in objects.items():
+        if _INTERFACES['Block'] not in interface_and_properties:
+            continue
+
+        block = BlockDevice(object_)
+        if block.id_usage != 'filesystem':
+            continue
+
+        device = {
+            'device': block.device,
+            'label': block.id_label,
+            'size': block.size,
+            'filesystem_type': block.id_type,
+            'is_removable': not block.hint_system
+        }
+        try:
+            file_system = Filesystem(object_)
+            device['mount_points'] = file_system.mount_points
+        except Exception:
+            continue
+        devices.append(device)
+
+    return devices
+
+
 def _mount(object_path):
     """Start the mount operation on an block device.