add power off drive functionality

README.md

@@ -34,4 +34,5 @@ Enter in ranger `:mount`, than will be shown menu. In this menu you can press:
 - `m` to mount selected partition
 - `u` to unmount selected partition
 - `e` to unmount all partitions of selected partition's drive
-- `ENTER` to open selected mountpoint in current tab
+- `p` to power off selected the selected partition's drive (also called safely remove). It can be done only when all partitions of the drive are unmounted
+- `ENTER` to open selected mountpoint in current tab of the ranger

menu.py

@@ -18,10 +18,8 @@ class ChoosePartition:
     selected_partn = 1
     selected_mountpoint = None
     partn = 1
-    help_message = [("Press 'm' to mount, " +
-                     "'u' to unmount, " +
-                     "'g' to refresh"),
-                    "  and 'e' to unmount, 'enter' to cd"]
+    help_message = ["Press 'm' to mount, 'u' to unmount, 'g' to refresh",
+                    "  and 'e' to unmount, 'p' to poweroff drive, 'enter' to cd"]
     message = ""
 
     def __init__(self):
@@ -62,6 +60,17 @@ class ChoosePartition:
                     return part
         return None
 
+    def _get_drive_by_partn(self):
+        partn = 0
+        for bd in self.blkinfo['blockdevices']:
+            if 'children' not in bd:
+                continue
+            for part in bd['children']:
+                partn += 1
+                if self.selected_partn == partn:
+                    return bd
+        return None
+
     def _select_print_part(self, part, is_selected, i):
         if not ('mountpoint' in part and
                 'name' in part and
@@ -175,6 +184,10 @@ class ChoosePartition:
                 sel = self._get_part_by_partn()
                 if sel is not None:
                     self.unmount(sel['path'])
+            elif x == ord('p'):
+                sel_drive = self._get_drive_by_partn()
+                if sel_drive is not None:
+                    self.poweroff(sel_drive['path'])
             elif x == ord('g') or x == ord('r'):
                 self._read_partitions()
         curses.endwin()
@@ -197,6 +210,9 @@ class ChoosePartition:
     def unmount(self, dev):
         self._udisk_mount_unmount("unmount", dev)
 
+    def poweroff(self, dev):
+        self._udisk_mount_unmount("power-off", dev)
+
     def mount(self, dev):
         self._udisk_mount_unmount("mount", dev)