redo udisks code from asunder for darbrrb purposes (WIP, #16)

udisks2.py

@@ -0,0 +1,109 @@
+import sys
+import logging
+import dbus
+from dbus.mainloop.glib import DBusGMainLoop
+from gi.repository import GObject
+from multiprocessing import Process, Queue
+from contextlib import contextmanager
+
+OFUD2Path = '/org/freedesktop/UDisks2'
+
+class OFUD2:
+    TOP = 'org.freedesktop.UDisks2'
+    Block = TOP + '.Block'
+    Filesystem = TOP + '.Filesystem'
+    Drive = TOP + '.Drive'
+
+OFDOM = 'org.freedesktop.DBus.ObjectManager'
+
+def process(q):
+    FORMAT = '%(asctime)-15s %(levelname)s %(name)s %(message)s'
+    logging.basicConfig(format=FORMAT, stream=sys.stderr, level=logging.DEBUG)
+    top = logging.getLogger(__name__)
+
+    top.debug('beginning')
+    DBusGMainLoop(set_as_default=True)
+
+    # http://stackoverflow.com/questions/5067005/python-udisks-enumerating-device-information
+    bus = dbus.SystemBus()
+    ud_om_obj = bus.get_object(OFUD2.TOP, '/org/freedesktop/UDisks2')
+    ud_om = dbus.Interface(ud_om_obj, OFDOM)
+
+    def listen_for_empties(bus_name, device_file, media_types=()):
+        log = logging.getLogger(__name__+'.listen_for_empties')
+        if len(media_types) == 0:
+            media_good = lambda x: True
+        else:
+            media_good = lambda x: x in media_types
+        def changed(interface_name, changed, invalidated):
+            if (
+                    changed.get('MediaAvailable', False) and
+                    changed.get('Optical', False) and
+                    changed.get('OpticalBlank', False)):
+                media_type = changed.get('Media', '')
+                log.info('A medium of type {} was '
+                              'inserted.'.format(media_type))
+                if media_good(media_type):
+                    # proper kind of empty disc inserted
+                    q.put(('blank', device_file))
+                else:
+                    log.info('The medium was not of the desired type.')
+                for k, v in changed.items():
+                    log.debug('{} is now {!r}'.format(k, v))
+        bus.add_signal_receiver(changed, 'PropertiesChanged',
+                                dbus.PROPERTIES_IFACE, path=bus_name)
+
+    def listen_and_mount_data_discs(bus_name):
+        log = logging.getLogger(__name__+'.listen_and_mount_data_discs')
+        def added(object_path, interfaces_and_properties):
+            log.debug('InterfacesAdded event')
+            log.debug(object_path)
+            log.debug(repr(interfaces_and_properties))
+            if object_path == bus_name:
+                for ifname, properties in interfaces_and_properties.items():
+                    if ifname == OFUD2.Filesystem:
+                        obj = bus.get_object(OFUD2.TOP, bus_name)
+                        fsi = dbus.Interface(obj, OFUD2.Filesystem)
+                        log.info('fs detected on {}, mounting'.format(bus_name))
+                        mtpt = fsi.mount()
+                        log.info('mounted at {}'.format(mtpt))
+                        q.put(('filesystem', mtpt))
+        bus.add_signal_receiver(added, 'InterfacesAdded', OFDOM,
+                                path=OFUD2Path)
+
+    top.debug('enumerating devices')
+    erthing = ud_om.GetManagedObjects()
+    for name, info in erthing.items():
+        for interface_name, getall in info.items():
+            if interface_name == OFUD2.Block:
+                device_file_name = (bytes(getall['Device']).
+                                    rstrip(b'\x00').decode('ascii'))
+                drive_path = getall['Drive']
+                if drive_path != '/': # if it is, this Block has no Drive
+                    drive_getall = erthing[drive_path][OFUD2.Drive]
+                    if (
+                            drive_getall['MediaRemovable'] and
+                            drive_getall['MediaChangeDetected'] and 
+                            any(z.startswith('optical')
+                                for z in drive_getall['MediaCompatibility'])):
+                        top.info('drive with removable '
+                                 'optical media {}'.format(device_file_name))
+                        listen_for_empties(drive_path, device_file_name)
+                        listen_and_mount_data_discs(name)
+    loop = GObject.MainLoop()
+    loop.run()
+
+@contextmanager
+def disc_inserted_queue():
+    q = Queue()
+    p = Process(target=process, args=(q,))
+    p.start()
+    yield q
+    q.close()
+    p.terminate()
+
+if __name__ == '__main__':
+    logging.basicConfig(stream=sys.stderr, level=logging.DEBUG)
+    with disc_inserted_queue() as q:
+        while True:
+            print(q.get())