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# Xandikos
# Copyright (C) 2017 Jelmer Vernooij <jelmer@jelmer.uk>, et al.
#
# 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; version 3
# of the License or (at your option) any later version of
# the License.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301, USA.
"""ICalendar file handling.
"""
import logging
from icalendar.cal import Calendar, component_factory
from xandikos.store import File, InvalidFileContents
def calendar_component_delta(old_cal, new_cal):
"""Find the differences between components in two calendars.
:param old_cal: Old calendar (can be None)
:param new_cal: New calendar (can be None)
:yield: (old_component, new_component) tuples (either can be None)
"""
by_uid = {}
by_content = {}
by_idx = {}
idx = 0
for component in getattr(old_cal, "subcomponents", []):
try:
by_uid[component["UID"]] = component
except KeyError:
by_content[component.to_ical()] = True
by_idx[idx] = component
idx += 1
idx = 0
for component in new_cal.subcomponents:
try:
old_component = by_uid.pop(component["UID"])
except KeyError:
if not by_content.pop(component.to_ical(), None):
# Not previously present
yield (by_idx.get(idx, component_factory[component.name]()),
component)
by_idx.pop(idx, None)
else:
yield (old_component, component)
for old_component in by_idx.values():
yield (old_component, component_factory[old_component.name]())
def calendar_prop_delta(old_component, new_component):
fields = set([field for field in old_component or []] +
[field for field in new_component or []])
for field in fields:
old_value = old_component.get(field)
new_value = new_component.get(field)
if (
getattr(old_value, 'to_ical', None) is None or
getattr(new_value, 'to_ical', None) is None or
old_value.to_ical() != new_value.to_ical()
):
yield (field, old_value, new_value)
def describe_component(component):
if component.name == "VTODO":
try:
return "task '%s'" % component["SUMMARY"]
except KeyError:
return "task"
else:
try:
return component["SUMMARY"]
except KeyError:
return "calendar item"
DELTA_IGNORE_FIELDS = set(["LAST-MODIFIED", "SEQUENCE", "DTSTAMP", "PRODID",
"CREATED", "COMPLETED", "X-MOZ-GENERATION",
"X-LIC-ERROR", "UID"])
def describe_calendar_delta(old_cal, new_cal):
"""Describe the differences between two calendars.
:param old_cal: Old calendar (can be None)
:param new_cal: New calendar (can be None)
:yield: Lines describing changes
"""
# TODO(jelmer): Extend
for old_component, new_component in calendar_component_delta(old_cal,
new_cal):
if not new_component:
yield "Deleted %s" % describe_component(old_component)
continue
description = describe_component(new_component)
if not old_component:
yield "Added %s" % describe_component(new_component)
continue
for field, old_value, new_value in calendar_prop_delta(old_component,
new_component):
if field.upper() in DELTA_IGNORE_FIELDS:
continue
if (
old_component.name.upper() == "VTODO" and
field.upper() == "STATUS"
):
yield "%s marked as %s" % (description, new_value)
elif field.upper() == 'DESCRIPTION':
yield "changed description of %s" % description
elif field.upper() == 'SUMMARY':
yield "changed summary of %s" % description
elif field.upper() == 'LOCATION':
yield "changed location of %s to %s" % (description, new_value)
elif (old_component.name.upper() == "VTODO" and
field.upper() == "PERCENT-COMPLETE"):
yield "%s marked as %d%% completed." % (
description, new_value)
elif field.upper() == 'DUE':
yield "changed due date for %s from %s to %s" % (
description, old_value.dt if old_value else 'none',
new_value.dt if new_value else 'none')
else:
yield "modified field %s in %s" % (field, description)
logging.debug("Changed %s/%s or %s/%s from %s to %s.",
old_component.name, field, new_component.name,
field, old_value, new_value)
class ICalendarFile(File):
"""Handle for ICalendar files."""
content_type = 'text/calendar'
def __init__(self, content, content_type):
super(ICalendarFile, self).__init__(content, content_type)
self._calendar = None
def validate(self):
"""Verify that file contents are valid."""
self.calendar
@property
def calendar(self):
if self._calendar is None:
try:
self._calendar = Calendar.from_ical(b''.join(self.content))
except ValueError:
raise InvalidFileContents(self.content_type, self.content)
return self._calendar
def describe_delta(self, name, previous):
try:
lines = list(describe_calendar_delta(
previous.calendar if previous else None, self.calendar))
except NotImplementedError:
lines = []
if not lines:
lines = super(ICalendarFile, self).describe_delta(name, previous)
return lines
def describe(self, name):
try:
subcomponents = self.calendar.subcomponents
except InvalidFileContents:
pass
else:
for component in subcomponents:
try:
return describe_component(component)
except KeyError:
pass
return super(ICalendarFile, self).describe(name)
def get_uid(self):
"""Extract the UID from a VCalendar file.
:param cal: Calendar, possibly serialized.
:return: UID
"""
for component in self.calendar.subcomponents:
try:
return component["UID"]
except KeyError:
pass
raise KeyError
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