gramps/gramps/gen/lib/attrbase.py

#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2000-2006  Donald N. Allingham
# Copyright (C) 2010       Michiel D. Nauta
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#

"""
AttributeRootBase class for Gramps.
"""

#-------------------------------------------------------------------------
#
# Gramps modules
#
#-------------------------------------------------------------------------
from .attribute import Attribute, AttributeRoot
from .srcattribute import SrcAttribute
from .const import IDENTICAL, EQUAL

#-------------------------------------------------------------------------
#
# AttributeRootBase class
#
#-------------------------------------------------------------------------
class AttributeRootBase:
    """
    Base class for attribute-aware objects.
    """
    _CLASS = AttributeRoot

    def __init__(self, source=None):
        """
        Initialize a AttributeBase.

        If the source is not None, then object is initialized from values of
        the source object.

        :param source: Object used to initialize the new object
        :type source: AttributeBase
        """
        if source:
            self.attribute_list = [self._CLASS(attribute)
                                   for attribute in source.attribute_list]
        else:
            self.attribute_list = []

    def serialize(self):
        """
        Convert the object to a serialized tuple of data.
        """
        return [attr.serialize() for attr in self.attribute_list]

    def to_struct(self):
        """
        Convert the data held in this object to a structure (eg,
        struct) that represents all the data elements.

        This method is used to recursively convert the object into a
        self-documenting form that can easily be used for various
        purposes, including diffs and queries.

        These structures may be primitive Python types (string,
        integer, boolean, etc.) or complex Python types (lists,
        tuples, or dicts). If the return type is a dict, then the keys
        of the dict match the fieldname of the object. If the return
        struct (or value of a dict key) is a list, then it is a list
        of structs. Otherwise, the struct is just the value of the
        attribute.

        :returns: Returns a struct containing the data of the object.
        :rtype: list
        """
        return [attr.to_struct() for attr in self.attribute_list]

    @classmethod
    def from_struct(cls, struct):
        """
        Given a struct data representation, return a serialized object.

        :returns: Returns a serialized object
        """
        return [cls._CLASS.from_struct(attr) for attr in struct]

    def unserialize(self, data):
        """
        Convert a serialized tuple of data to an object.
        """
        self.attribute_list = [self._CLASS().unserialize(item) for item in data]

    def add_attribute(self, attribute):
        """
        Add the :class:`~.attribute.Attribute` instance to the object's list of
        attributes.

        :param attribute: :class:`~.attribute.Attribute` instance to add.
        :type attribute: :class:`~.attribute.Attribute`
        """
        assert not isinstance(attribute, str)
        self.attribute_list.append(attribute)

    def remove_attribute(self, attribute):
        """
        Remove the specified :class:`~.attribute.Attribute` instance from the
        attribute list.

        If the instance does not exist in the list, the operation has
        no effect.

        :param attribute: :class:`~.attribute.Attribute` instance to remove
                          from the list
        :type attribute: :class:`~.attribute.Attribute`

        :returns: True if the attribute was removed, False if it was not in the
                  list.
        :rtype: bool
        """
        if attribute in self.attribute_list:
            self.attribute_list.remove(attribute)
            return True
        else:
            return False

    def get_attribute_list(self):
        """
        Return the list of :class:`~.attribute.Attribute` instances associated
        with the object.

        :returns: Returns the list of :class:`~.attribute.Attribute` instances.
        :rtype: list
        """
        return self.attribute_list

    def set_attribute_list(self, attribute_list):
        """
        Assign the passed list to the Person's list of
        :class:`~.attribute.Attribute` instances.

        :param attribute_list: List of :class:`~.attribute.Attribute` instances
                               to ba associated with the Person
        :type attribute_list: list
        """
        self.attribute_list = attribute_list

    def _merge_attribute_list(self, acquisition):
        """
        Merge the list of attributes from acquisition with our own.

        :param acquisition: the attribute list of this object will be merged
                            with the current attribute list.
        :type acquisition: AttributeBase
        """
        attr_list = self.attribute_list[:]
        for addendum in acquisition.get_attribute_list():
            for attr in attr_list:
                equi = attr.is_equivalent(addendum)
                if equi == IDENTICAL:
                    break
                elif equi == EQUAL:
                    attr.merge(addendum)
                    break
            else:
                self.attribute_list.append(addendum)

class AttributeBase(AttributeRootBase):
    _CLASS = Attribute

class SrcAttributeBase(AttributeRootBase):
    _CLASS = SrcAttribute