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):
class TreeManager(models.Manager):
use_for_related_fields = True
- def roots(self):
- return self.filter(parent__isnull=True)
-
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.
# 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)
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):
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.
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
+
+ depth += (len(segments) - depth)/2 or len(segments) - depth
- deepest_found = depth
- depth = (len(segments) + depth)/2
+ if depth > deepest_level + obj.get_descendant_count():
+ depth = deepest_level + obj.get_descendant_count()
- if deepest_found == depth:
- return obj, build_path(segments[deepest_found:]) or None
+ 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:])
- return find_obj(segments, len(segments), 0)
+ if absolute_result:
+ return self.get(**make_query_kwargs(segments, root))
+
+ # 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):
- parent = self
- while parent:
- if parent == ancestor:
- return True
- parent = parent.parent
- return False
-
def get_path(self, root=None, pathsep='/', field='slug'):
- if root is not None and not self.has_ancestor(root):
+ if root == self:
+ return ''
+
+ if root is not None and not self.is_descendant_of(root):
raise AncestorDoesNotExist(root)
- path = getattr(self, field, '?')
- parent = self.parent
- while parent and parent != root:
- path = getattr(parent, field, '?') + pathsep + path
- parent = parent.parent
- return path
+ qs = self.get_ancestors()
+
+ if root is not None:
+ qs = qs.filter(level__gt=root.level)
+
+ return pathsep.join([getattr(parent, field, '?') for parent in list(qs) + [self]])
path = property(get_path)
def __unicode__(self):
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:
git.ithinksw.org / philo.git / blobdiff