app/django/db/models/related.py
author Daniel Bentley <dbentley@google.com>
Sun, 12 Apr 2009 09:06:45 +0000
branchgae-fetch-limitation-fix
changeset 2313 c39a81bce1bd
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Use offset_linkid instead of offset to scan >1000 entities. this is a first-cut. It works in all the ways I could make earlier versions fail. It passes link_id as URL parameters. It also has a new class LinkCreator which makes the main body of getListContents even easier to write. I wasn't sure if link_id's could have non alphanumeric characters; if so, they need to be URL encoded/decoded. I also need to go and remove any mention of raw offsets now, because we don't use them. I believe I've talked about this approach with a few of you and it sounded reasonable. Feel free to roll-back/fix/amend/comment-for-me-to-fix. This is my first big-logic-change to Melange. Patch by: Dan Bentley

class BoundRelatedObject(object):
    def __init__(self, related_object, field_mapping, original):
        self.relation = related_object
        self.field_mappings = field_mapping[related_object.name]

    def template_name(self):
        raise NotImplementedError

    def __repr__(self):
        return repr(self.__dict__)

class RelatedObject(object):
    def __init__(self, parent_model, model, field):
        self.parent_model = parent_model
        self.model = model
        self.opts = model._meta
        self.field = field
        self.name = '%s:%s' % (self.opts.app_label, self.opts.module_name)
        self.var_name = self.opts.object_name.lower()

    def get_db_prep_lookup(self, lookup_type, value):
        # Defer to the actual field definition for db prep
        return self.field.get_db_prep_lookup(lookup_type, value)

    def editable_fields(self):
        "Get the fields in this class that should be edited inline."
        return [f for f in self.opts.fields + self.opts.many_to_many if f.editable and f != self.field]

    def __repr__(self):
        return "<RelatedObject: %s related to %s>" % (self.name, self.field.name)

    def bind(self, field_mapping, original, bound_related_object_class=BoundRelatedObject):
        return bound_related_object_class(self, field_mapping, original)

    def get_accessor_name(self):
        # This method encapsulates the logic that decides what name to give an
        # accessor descriptor that retrieves related many-to-one or
        # many-to-many objects. It uses the lower-cased object_name + "_set",
        # but this can be overridden with the "related_name" option.
        if self.field.rel.multiple:
            # If this is a symmetrical m2m relation on self, there is no reverse accessor.
            if getattr(self.field.rel, 'symmetrical', False) and self.model == self.parent_model:
                return None
            return self.field.rel.related_name or (self.opts.object_name.lower() + '_set')
        else:
            return self.field.rel.related_name or (self.opts.object_name.lower())