def get_with_path(self, path, root=None, absolute_result=True, pathsep='/', field='slug'):
"""
- Given a <pathsep>-separated path, fetch the matching model of this type. 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.
+ 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
kwargs["%s%s__exact" % (prefix, field)] = segment
prefix += "parent__"
- if not prefix and root is not None:
- prefix = "parent__"
-
if prefix:
kwargs[prefix[:-2]] = root
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
- else:
+ 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[deepest_level:depth], deepest_found))
+ obj = self.get(**make_query_kwargs(segments[deepest_level:depth], deepest_found or root))
except self.model.DoesNotExist:
if not deepest_level and depth > 1:
# make sure there's a root node...
if deepest_level == depth:
# This should happen if nothing is found with any part of the given path.
+ if root is not None:
+ return root, build_path(segments)
raise
return find_obj(segments, depth, deepest_found)
else:
# Yay! Found one!
- deepest_level = obj.get_level() + 1
+ 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():
# 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), root)
+ return find_obj(segments, len(segments)/2 or len(segments))
class TreeModel(MPTTModel):
slug = models.SlugField(max_length=255)
def get_path(self, root=None, pathsep='/', field='slug'):
+ if root == self:
+ return ''
+
if root is not None and not self.is_descendant_of(root):
raise AncestorDoesNotExist(root)
- return pathsep.join([getattr(parent, field, '?') for parent in list(self.get_ancestors()) + [self]])
+ 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):