"""
Different versions of the Python DBus bindings return different types
to represent integers, strings, lists, etc. Older versions return
builtin Python types: C{int}, C{str}, C{list}, etc. Newer versions
return DBus-specific wrappers: C{Int16}, C{String}, C{Array}, etc.
Failures occur when DBus types are used because bpickle doesn't know
that an C{Int16} is really an C{int} and that an C{Array} is really a
C{list}.

L{install} and L{uninstall} can install and remove extensions that
make bpickle work with DBus types.
"""

import dbus

from landscape.lib import bpickle


def install():
"""Install bpickle extensions for DBus types."""
for type, function in get_dbus_types():
bpickle.dumps_table[type] = function


def uninstall():
"""Uninstall bpickle extensions for DBus types."""
for type, function in get_dbus_types():
del bpickle.dumps_table[type]


def dumps_utf8string(obj):
"""
Convert the specified L{dbus.types.UTF8String} to bpickle's
representation for C{unicode} data.
"""
return "u%s:%s" % (len(obj), obj)


def dumps_double(obj):
"""
Convert a dbus.types.Double into a floating point representation.
"""
return "f%r;" % float(obj)


def get_dbus_types():
"""
Generator yields C{(type, bpickle_function)} for available DBus
types.
"""
for (type_name, function) in [("Boolean", bpickle.dumps_bool),
("Int16", bpickle.dumps_int),
("UInt16", bpickle.dumps_int),
("Int32", bpickle.dumps_int),
("UInt32", bpickle.dumps_int),
("Int64", bpickle.dumps_int),
("UInt64", bpickle.dumps_int),
("Double", dumps_double),
("Array", bpickle.dumps_list),
("Dictionary", bpickle.dumps_dict),
("String", bpickle.dumps_unicode),
("UTF8String", dumps_utf8string)]:
type = getattr(dbus.types, type_name, None)
if type is not None:
yield type, function