+ class ActiveTask(Exception):
+ """
+ Raised when the operation cannot be performed on the active task.
+ """
+ pass
+
+ class InactiveTask(Exception):
+ """
+ Raised when the operation cannot be performed on an inactive task.
+ """
+ pass
+
+ class NotSaved(Exception):
+ """
+ Raised when the operation cannot be performed on the task, because
+ it has not been saved to TaskWarrior yet.
+ """
+ pass
+
+ @classmethod
+ def from_input(cls, input_file=sys.stdin, modify=None, backend=None):
+ """
+ Creates a Task object, directly from the stdin, by reading one line.
+ If modify=True, two lines are used, first line interpreted as the
+ original state of the Task object, and second line as its new,
+ modified value. This is consistent with the TaskWarrior's hook
+ system.
+
+ Object created by this method should not be saved, deleted
+ or refreshed, as t could create a infinite loop. For this
+ reason, TaskWarrior instance is set to None.
+
+ Input_file argument can be used to specify the input file,
+ but defaults to sys.stdin.
+ """
+
+ # Detect the hook type if not given directly
+ name = os.path.basename(sys.argv[0])
+ modify = name.startswith('on-modify') if modify is None else modify
+
+ # Create the TaskWarrior instance if none passed
+ if backend is None:
+ backends = importlib.import_module('tasklib.backends')
+ hook_parent_dir = os.path.dirname(os.path.dirname(sys.argv[0]))
+ backend = backends.TaskWarrior(data_location=hook_parent_dir)
+
+ # TaskWarrior instance is set to None
+ task = cls(backend)
+
+ # Load the data from the input
+ task._load_data(json.loads(input_file.readline().strip()))
+
+ # If this is a on-modify event, we are provided with additional
+ # line of input, which provides updated data
+ if modify:
+ task._update_data(json.loads(input_file.readline().strip()),
+ remove_missing=True)
+
+ return task
+
+ def __init__(self, backend, **kwargs):
+ super(Task, self).__init__(backend)
+
+ # Check that user is not able to set read-only value in __init__
+ for key in kwargs.keys():
+ if key in self.read_only_fields:
+ raise RuntimeError('Field \'%s\' is read-only' % key)
+
+ # We serialize the data in kwargs so that users of the library
+ # do not have to pass different data formats via __setitem__ and
+ # __init__ methods, that would be confusing
+
+ # Rather unfortunate syntax due to python2.6 comaptiblity
+ self._data = dict((key, self._normalize(key, value))
+ for (key, value) in six.iteritems(kwargs))
+ self._original_data = copy.deepcopy(self._data)
+
+ # Provide read only access to the original data
+ self.original = ReadOnlyDictView(self._original_data)