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XSettings implementation in Python 3
#!/usr/bin/env python3
# Implementation of XSettings specification in Python 3
# <http://standards.freedesktop.org/xsettings-spec/xsettings-spec-0.5.html>
#
# Copyright (C) 2015 Dmitry Shachnev <mitya57@gmail.com>
#
# 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 2 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/>.
import ctypes
import ctypes.util
import struct
import sys
class _xcb_reply_t(ctypes.Structure):
# this can be used instead of xcb_intern_atom_reply_t,
# xcb_get_selection_owner_reply_t, etc
_fields_ = [('response_type', ctypes.c_uint8),
('pad0', ctypes.c_uint8),
('sequence', ctypes.c_uint16),
('length', ctypes.c_uint32),
('payload', ctypes.c_uint32)]
class _xcb_cookie_t(ctypes.Structure):
# this can be used instead of xcb_intern_atom_cookie_t,
# xcb_get_selection_owner_cookie_t, etc
_fields_ = [('sequence', ctypes.c_uint)]
_xcb_error_messages = [
None,
'XCB error: socket, pipe and other stream error',
'XCB connection closed: extension unsupported',
'XCB connection closed: insufficient memory',
'XCB connection closed: request length exceeded',
'XCB connection closed: DISPLAY parse error',
'XCB connection closed: invalid screen'
]
class XSettingsError(RuntimeError):
pass
class XSettingsParseError(XSettingsError):
pass
def get_raw_xsettings(display=0):
# initialize the libraries
xcb_library_name = ctypes.util.find_library('xcb')
if xcb_library_name is None:
raise XSettingsError('Xcb library not found')
xcb = ctypes.CDLL(xcb_library_name)
c_library_name = ctypes.util.find_library('c')
if c_library_name is None:
raise XSettingsError('C library not found')
c = ctypes.CDLL(c_library_name)
# set some args and return types
c.free.argtypes = [ctypes.c_void_p]
c.free.restype = None
xcb.xcb_connect.argtypes = [ctypes.c_char_p, ctypes.POINTER(ctypes.c_int)]
xcb.xcb_connect.restype = ctypes.c_void_p
xcb.xcb_connection_has_error.argtypes = [ctypes.c_void_p]
xcb.xcb_connection_has_error.restype = ctypes.c_int
xcb.xcb_disconnect.argtypes = [ctypes.c_void_p]
xcb.xcb_disconnect.restype = None
xcb.xcb_intern_atom.argtypes = [ctypes.c_void_p, ctypes.c_uint8, ctypes.c_uint16, ctypes.c_char_p]
xcb.xcb_intern_atom.restype = _xcb_cookie_t
xcb.xcb_intern_atom_reply.argtypes = [ctypes.c_void_p, _xcb_cookie_t, ctypes.c_void_p]
xcb.xcb_intern_atom_reply.restype = ctypes.POINTER(_xcb_reply_t)
xcb.xcb_get_selection_owner.argtypes = [ctypes.c_void_p, ctypes.c_uint32]
xcb.xcb_get_selection_owner.restype = _xcb_cookie_t
xcb.xcb_get_selection_owner_reply.argtypes = [ctypes.c_void_p, _xcb_cookie_t, ctypes.c_void_p]
xcb.xcb_get_selection_owner_reply.restype = ctypes.POINTER(_xcb_reply_t)
xcb.xcb_get_property.argtypes = [ctypes.c_void_p, ctypes.c_uint8, ctypes.c_uint32, ctypes.c_uint32,
ctypes.c_uint32, ctypes.c_uint32]
xcb.xcb_get_property.restype = _xcb_cookie_t
xcb.xcb_get_property_reply.argtypes = [ctypes.c_void_p, _xcb_cookie_t, ctypes.c_void_p]
xcb.xcb_get_property_reply.restype = ctypes.c_void_p
xcb.xcb_get_property_value_length.argtypes = [ctypes.c_void_p]
xcb.xcb_get_property_value_length.restype = ctypes.c_int
xcb.xcb_get_property_value.argtypes = [ctypes.c_void_p]
xcb.xcb_get_property_value.restype = ctypes.c_void_p
# open the connection
connection = xcb.xcb_connect(None, None)
error = xcb.xcb_connection_has_error(connection)
if error:
raise XSettingsError(_xcb_error_messages[error])
# get selection atom cookie
buffer = ('_XSETTINGS_S%d' % display).encode()
cookie = xcb.xcb_intern_atom(connection, 0, len(buffer), buffer)
# get selection atom reply
reply = xcb.xcb_intern_atom_reply(connection, cookie, None)
selection_atom = reply.contents.payload
c.free(reply)
# get selection owner cookie
cookie = xcb.xcb_get_selection_owner(connection, selection_atom)
# get selection owner reply
reply = xcb.xcb_get_selection_owner_reply(connection, cookie, None)
window = reply.contents.payload
c.free(reply)
# get settings atom cookie
buffer = b'_XSETTINGS_SETTINGS'
cookie = xcb.xcb_intern_atom(connection, 0, len(buffer), buffer)
# get settings atom reply
reply = xcb.xcb_intern_atom_reply(connection, cookie, None)
settings_atom = reply.contents.payload
c.free(reply)
# get property cookie
cookie = xcb.xcb_get_property(connection, 0, window, settings_atom, 0, 0, 0x2000)
# get property reply
reply = xcb.xcb_get_property_reply(connection, cookie, None)
if reply is not None:
length = xcb.xcb_get_property_value_length(reply)
pointer = xcb.xcb_get_property_value(reply) if length else None
result = ctypes.string_at(pointer, length)
c.free(reply)
# close the connection
xcb.xcb_disconnect(connection)
# handle possible errors
if reply is None or not length:
raise XSettingsError('XSettings not available')
return result
def parse_xsettings(raw_xsettings):
if len(raw_xsettings) < 12:
raise XSettingsParseError('length < 12')
if raw_xsettings[0] not in (0, 1):
raise XSettingsParseError('wrong order byte: %d' % raw_xsettings[0])
byte_order = '<>'[raw_xsettings[0]]
settings_count = struct.unpack(byte_order + 'I', raw_xsettings[8:12])[0]
TypeInteger, TypeString, TypeColor = range(3)
result = {}
raw_xsettings = raw_xsettings[12:]
offset = 0
for i in range(settings_count):
setting_type = raw_xsettings[offset]
offset += 2
name_length = struct.unpack(byte_order + 'H', raw_xsettings[offset:offset + 2])[0]
offset += 2
name = raw_xsettings[offset:offset + name_length]
offset += name_length
if offset & 3:
offset += 4 - (offset & 3)
offset += 4 # skip last-change-serial
if setting_type == TypeInteger:
value = struct.unpack(byte_order + 'I', raw_xsettings[offset:offset + 4])[0]
offset += 4
elif setting_type == TypeString:
value_length = struct.unpack(byte_order + 'I', raw_xsettings[offset:offset + 4])[0]
offset += 4
value = raw_xsettings[offset:offset + value_length]
offset += value_length
if offset & 3:
offset += 4 - (offset & 3)
elif setting_type == TypeColor:
value = struct.unpack(byte_order + 'HHHH', raw_xsettings[offset:offset + 8])
offset += 8
else:
raise XSettingsParseError('Wrong setting type: %d' % setting_type)
result[name] = value
return result
def get_xsettings(display=0):
raw_xsettings = get_raw_xsettings(display)
return parse_xsettings(raw_xsettings)
if __name__ == '__main__':
try:
xsettings = get_xsettings()
except XSettingsError as e:
sys.exit(e)
for setting, value in sorted(xsettings.items()):
setting = setting.decode()
if isinstance(value, bytes):
value = value.decode()
print('%s:' % setting, value)
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