From d03c8d2d2efaf848b01e96863c29f46ce3a0db21 Mon Sep 17 00:00:00 2001 From: SVN-Git Migration Date: Thu, 8 Oct 2015 11:51:46 -0700 Subject: Imported Upstream version 0.2.1+svn147 --- tagging/.svn/text-base/generic.py.svn-base | 40 ++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 tagging/.svn/text-base/generic.py.svn-base (limited to 'tagging/.svn/text-base/generic.py.svn-base') diff --git a/tagging/.svn/text-base/generic.py.svn-base b/tagging/.svn/text-base/generic.py.svn-base new file mode 100644 index 0000000..75d1b8e --- /dev/null +++ b/tagging/.svn/text-base/generic.py.svn-base @@ -0,0 +1,40 @@ +from django.contrib.contenttypes.models import ContentType + +def fetch_content_objects(tagged_items, select_related_for=None): + """ + Retrieves ``ContentType`` and content objects for the given list of + ``TaggedItems``, grouping the retrieval of content objects by model + type to reduce the number of queries executed. + + This results in ``number_of_content_types + 1`` queries rather than + the ``number_of_tagged_items * 2`` queries you'd get by iterating + over the list and accessing each item's ``object`` attribute. + + A ``select_related_for`` argument can be used to specify a list of + of model names (corresponding to the ``model`` field of a + ``ContentType``) for which ``select_related`` should be used when + retrieving model instances. + """ + if select_related_for is None: select_related_for = [] + + # Group content object pks by their content type pks + objects = {} + for item in tagged_items: + objects.setdefault(item.content_type_id, []).append(item.object_id) + + # Retrieve content types and content objects in bulk + content_types = ContentType._default_manager.in_bulk(objects.keys()) + for content_type_pk, object_pks in objects.iteritems(): + model = content_types[content_type_pk].model_class() + if content_types[content_type_pk].model in select_related_for: + objects[content_type_pk] = model._default_manager.select_related().in_bulk(object_pks) + else: + objects[content_type_pk] = model._default_manager.in_bulk(object_pks) + + # Set content types and content objects in the appropriate cache + # attributes, so accessing the 'content_type' and 'object' + # attributes on each tagged item won't result in further database + # hits. + for item in tagged_items: + item._object_cache = objects[item.content_type_id][item.object_id] + item._content_type_cache = content_types[item.content_type_id] -- cgit v1.2.3