X-Git-Url: http://git.ithinksw.org/philo.git/blobdiff_plain/05bdd3ca32b67c218f7d58c2def2661867b4d1fa..e095f691f243784f8c8d0a9773270b9dbead18e9:/models/base.py diff --git a/models/base.py b/models/base.py index 03b9b54..c7b1c26 100644 --- a/models/base.py +++ b/models/base.py @@ -10,6 +10,7 @@ from philo.utils import ContentTypeRegistryLimiter, ContentTypeSubclassLimiter from philo.signals import entity_class_prepared from philo.validators import json_validator from UserDict import DictMixin +from mptt.models import MPTTModel, MPTTModelBase, MPTTOptions class Tag(models.Model): @@ -279,36 +280,21 @@ class Entity(models.Model): class TreeManager(models.Manager): use_for_related_fields = True - def roots(self): - return self.filter(parent__isnull=True) - - def get_branch_pks(self, root, depth=5, inclusive=True): - branch_pks = [] - parent_pks = [root.pk] - - if inclusive: - branch_pks.append(root.pk) - - for i in xrange(depth): - child_pks = list(self.filter(parent__pk__in=parent_pks).exclude(pk__in=branch_pks).values_list('pk', flat=True)) - if not child_pks: - break - - branch_pks += child_pks - parent_pks = child_pks - - return branch_pks - - def get_branch(self, root, depth=5, inclusive=True): - return self.filter(pk__in=self.get_branch_pks(root, depth, inclusive)) - def get_with_path(self, path, root=None, absolute_result=True, pathsep='/', field='slug'): """ Returns the object with the path, unless absolute_result is set to False, in which case it returns a tuple containing the deepest object found along the path, and the remainder of the path after that object as a string (or None if there is no remaining path). Raises a DoesNotExist exception if no object is found with the given path. + + If the path you're searching for is known to exist, it is always faster to use + absolute_result=True - unless the path depth is over ~40, in which case the high cost + of the absolute query makes a binary search (i.e. non-absolute) faster. """ + # Note: SQLite allows max of 64 tables in one join. That means the binary search will + # only work on paths with a max depth of 127 and the absolute fetch will only work + # to a max depth of (surprise!) 63. Although this could be handled, chances are your + # tree structure won't be that deep. segments = path.split(pathsep) # Check for a trailing pathsep so we can restore it later. @@ -326,11 +312,13 @@ class TreeManager(models.Manager): # Special-case a lack of segments. No queries necessary. if not segments: if root is not None: + if absolute_result: + return root return root, None else: raise self.model.DoesNotExist('%s matching query does not exist.' % self.model._meta.object_name) - def make_query_kwargs(segments): + def make_query_kwargs(segments, root): kwargs = {} prefix = "" revsegs = list(segments) @@ -340,7 +328,9 @@ class TreeManager(models.Manager): kwargs["%s%s__exact" % (prefix, field)] = segment prefix += "parent__" - kwargs[prefix[:-2]] = root + if prefix: + kwargs[prefix[:-2]] = root + return kwargs def build_path(segments): @@ -349,86 +339,83 @@ class TreeManager(models.Manager): path += pathsep return path - def find_obj(segments, depth, deepest_found): + def find_obj(segments, depth, deepest_found=None): + if deepest_found is None: + deepest_level = 0 + elif root is None: + deepest_level = deepest_found.get_level() + 1 + else: + deepest_level = deepest_found.get_level() - root.get_level() try: - obj = self.get(**make_query_kwargs(segments[:depth])) + obj = self.get(**make_query_kwargs(segments[deepest_level:depth], deepest_found or root)) except self.model.DoesNotExist: - if absolute_result: - raise + if not deepest_level and depth > 1: + # make sure there's a root node... + depth = 1 + else: + # Try finding one with half the path since the deepest find. + depth = (deepest_level + depth)/2 - depth = (deepest_found + depth)/2 - if deepest_found == depth: + if deepest_level == depth: # This should happen if nothing is found with any part of the given path. + if root is not None and deepest_found is None: + return root, build_path(segments) raise - # Try finding one with half the path since the deepest find. return find_obj(segments, depth, deepest_found) else: - # Yay! Found one! Could there be a deeper one? - if absolute_result: - return obj + # Yay! Found one! + if root is None: + deepest_level = obj.get_level() + 1 + else: + deepest_level = obj.get_level() - root.get_level() + + # Could there be a deeper one? + if obj.is_leaf_node(): + return obj, build_path(segments[deepest_level:]) or None - deepest_found = depth - depth = (len(segments) + depth)/2 + depth += (len(segments) - depth)/2 or len(segments) - depth - if deepest_found == depth: - return obj, build_path(segments[deepest_found:]) or None + if depth > deepest_level + obj.get_descendant_count(): + depth = deepest_level + obj.get_descendant_count() + + if deepest_level == depth: + return obj, build_path(segments[deepest_level:]) or None try: - return find_obj(segments, depth, deepest_found) + return find_obj(segments, depth, obj) except self.model.DoesNotExist: - # Then the deepest one was already found. - return obj, build_path(segments[deepest_found:]) + # Then this was the deepest. + return obj, build_path(segments[deepest_level:]) + + if absolute_result: + return self.get(**make_query_kwargs(segments, root)) - return find_obj(segments, len(segments), 0) + # Try a modified binary search algorithm. Feed the root in so that query complexity + # can be reduced. It might be possible to weight the search towards the beginning + # of the path, since short paths are more likely, but how far forward? It would + # need to shift depending on len(segments) - perhaps logarithmically? + return find_obj(segments, len(segments)/2 or len(segments)) -class TreeModel(models.Model): +class TreeModel(MPTTModel): objects = TreeManager() parent = models.ForeignKey('self', related_name='children', null=True, blank=True) slug = models.SlugField(max_length=255) - def has_ancestor(self, ancestor, inclusive=False): - if inclusive: - parent = self - else: - parent = self.parent - - parents = [] - - while parent: - if parent == ancestor: - return True - # If we've found this parent before, the path is recursive and ancestor wasn't on it. - if parent in parents: - return False - parents.append(parent) - parent = parent.parent - # If ancestor is None, catch it here. - if parent == ancestor: - return True - return False - def get_path(self, root=None, pathsep='/', field='slug'): - parent = self.parent - parents = [self] + if root == self: + return '' - def compile_path(parents): - return pathsep.join([getattr(parent, field, '?') for parent in parents]) + if root is not None and not self.is_descendant_of(root): + raise AncestorDoesNotExist(root) - while parent and parent != root: - if parent in parents: - if root is not None: - raise AncestorDoesNotExist(root) - parents.append(parent) - return u"\u2026%s%s" % (pathsep, compile_path(parents[::-1])) - parents.append(parent) - parent = parent.parent + qs = self.get_ancestors() - if root is not None and parent is None: - raise AncestorDoesNotExist(root) + if root is not None: + qs = qs.filter(**{'%s__gt' % self._mptt_meta.level_attr: root.get_level()}) - return compile_path(parents[::-1]) + return pathsep.join([getattr(parent, field, '?') for parent in list(qs) + [self]]) path = property(get_path) def __unicode__(self): @@ -439,7 +426,17 @@ class TreeModel(models.Model): abstract = True +class TreeEntityBase(MPTTModelBase, EntityBase): + def __new__(meta, name, bases, attrs): + attrs['_mptt_meta'] = MPTTOptions(attrs.pop('MPTTMeta', None)) + cls = EntityBase.__new__(meta, name, bases, attrs) + + return meta.register(cls) + + class TreeEntity(Entity, TreeModel): + __metaclass__ = TreeEntityBase + @property def attributes(self): if self.parent: