django1/django/utils/datastructures.py

342 lines
11 KiB
Python

class MergeDict(object):
"""
A simple class for creating new "virtual" dictionaries that actually look
up values in more than one dictionary, passed in the constructor.
If a key appears in more than one of the given dictionaries, only the
first occurrence will be used.
"""
def __init__(self, *dicts):
self.dicts = dicts
def __getitem__(self, key):
for dict_ in self.dicts:
try:
return dict_[key]
except KeyError:
pass
raise KeyError
def __copy__(self):
return self.__class__(*self.dicts)
def get(self, key, default=None):
try:
return self[key]
except KeyError:
return default
def getlist(self, key):
for dict_ in self.dicts:
if key in dict_.keys():
return dict_.getlist(key)
return []
def items(self):
item_list = []
for dict_ in self.dicts:
item_list.extend(dict_.items())
return item_list
def has_key(self, key):
for dict_ in self.dicts:
if key in dict_:
return True
return False
__contains__ = has_key
def copy(self):
"""Returns a copy of this object."""
return self.__copy__()
class SortedDict(dict):
"""
A dictionary that keeps its keys in the order in which they're inserted.
"""
def __init__(self, data=None):
if data is None:
data = {}
super(SortedDict, self).__init__(data)
if isinstance(data, dict):
self.keyOrder = data.keys()
else:
self.keyOrder = []
for key, value in data:
if key not in self.keyOrder:
self.keyOrder.append(key)
def __deepcopy__(self, memo):
from copy import deepcopy
return self.__class__([(key, deepcopy(value, memo))
for key, value in self.iteritems()])
def __setitem__(self, key, value):
super(SortedDict, self).__setitem__(key, value)
if key not in self.keyOrder:
self.keyOrder.append(key)
def __delitem__(self, key):
super(SortedDict, self).__delitem__(key)
self.keyOrder.remove(key)
def __iter__(self):
for k in self.keyOrder:
yield k
def pop(self, k, *args):
result = super(SortedDict, self).pop(k, *args)
try:
self.keyOrder.remove(k)
except ValueError:
# Key wasn't in the dictionary in the first place. No problem.
pass
return result
def popitem(self):
result = super(SortedDict, self).popitem()
self.keyOrder.remove(result[0])
return result
def items(self):
return zip(self.keyOrder, self.values())
def iteritems(self):
for key in self.keyOrder:
yield key, super(SortedDict, self).__getitem__(key)
def keys(self):
return self.keyOrder[:]
def iterkeys(self):
return iter(self.keyOrder)
def values(self):
return [super(SortedDict, self).__getitem__(k) for k in self.keyOrder]
def itervalues(self):
for key in self.keyOrder:
yield super(SortedDict, self).__getitem__(key)
def update(self, dict_):
for k, v in dict_.items():
self.__setitem__(k, v)
def setdefault(self, key, default):
if key not in self.keyOrder:
self.keyOrder.append(key)
return super(SortedDict, self).setdefault(key, default)
def value_for_index(self, index):
"""Returns the value of the item at the given zero-based index."""
return self[self.keyOrder[index]]
def insert(self, index, key, value):
"""Inserts the key, value pair before the item with the given index."""
if key in self.keyOrder:
n = self.keyOrder.index(key)
del self.keyOrder[n]
if n < index:
index -= 1
self.keyOrder.insert(index, key)
super(SortedDict, self).__setitem__(key, value)
def copy(self):
"""Returns a copy of this object."""
# This way of initializing the copy means it works for subclasses, too.
obj = self.__class__(self)
obj.keyOrder = self.keyOrder
return obj
def __repr__(self):
"""
Replaces the normal dict.__repr__ with a version that returns the keys
in their sorted order.
"""
return '{%s}' % ', '.join(['%r: %r' % (k, v) for k, v in self.items()])
class MultiValueDictKeyError(KeyError):
pass
class MultiValueDict(dict):
"""
A subclass of dictionary customized to handle multiple values for the
same key.
>>> d = MultiValueDict({'name': ['Adrian', 'Simon'], 'position': ['Developer']})
>>> d['name']
'Simon'
>>> d.getlist('name')
['Adrian', 'Simon']
>>> d.get('lastname', 'nonexistent')
'nonexistent'
>>> d.setlist('lastname', ['Holovaty', 'Willison'])
This class exists to solve the irritating problem raised by cgi.parse_qs,
which returns a list for every key, even though most Web forms submit
single name-value pairs.
"""
def __init__(self, key_to_list_mapping=()):
super(MultiValueDict, self).__init__(key_to_list_mapping)
def __repr__(self):
return "<%s: %s>" % (self.__class__.__name__,
super(MultiValueDict, self).__repr__())
def __getitem__(self, key):
"""
Returns the last data value for this key, or [] if it's an empty list;
raises KeyError if not found.
"""
try:
list_ = super(MultiValueDict, self).__getitem__(key)
except KeyError:
raise MultiValueDictKeyError, "Key %r not found in %r" % (key, self)
try:
return list_[-1]
except IndexError:
return []
def __setitem__(self, key, value):
super(MultiValueDict, self).__setitem__(key, [value])
def __copy__(self):
return self.__class__(super(MultiValueDict, self).items())
def __deepcopy__(self, memo=None):
import copy
if memo is None:
memo = {}
result = self.__class__()
memo[id(self)] = result
for key, value in dict.items(self):
dict.__setitem__(result, copy.deepcopy(key, memo),
copy.deepcopy(value, memo))
return result
def get(self, key, default=None):
"""
Returns the last data value for the passed key. If key doesn't exist
or value is an empty list, then default is returned.
"""
try:
val = self[key]
except KeyError:
return default
if val == []:
return default
return val
def getlist(self, key):
"""
Returns the list of values for the passed key. If key doesn't exist,
then an empty list is returned.
"""
try:
return super(MultiValueDict, self).__getitem__(key)
except KeyError:
return []
def setlist(self, key, list_):
super(MultiValueDict, self).__setitem__(key, list_)
def setdefault(self, key, default=None):
if key not in self:
self[key] = default
return self[key]
def setlistdefault(self, key, default_list=()):
if key not in self:
self.setlist(key, default_list)
return self.getlist(key)
def appendlist(self, key, value):
"""Appends an item to the internal list associated with key."""
self.setlistdefault(key, [])
super(MultiValueDict, self).__setitem__(key, self.getlist(key) + [value])
def items(self):
"""
Returns a list of (key, value) pairs, where value is the last item in
the list associated with the key.
"""
return [(key, self[key]) for key in self.keys()]
def lists(self):
"""Returns a list of (key, list) pairs."""
return super(MultiValueDict, self).items()
def values(self):
"""Returns a list of the last value on every key list."""
return [self[key] for key in self.keys()]
def copy(self):
"""Returns a copy of this object."""
return self.__deepcopy__()
def update(self, *args, **kwargs):
"""
update() extends rather than replaces existing key lists.
Also accepts keyword args.
"""
if len(args) > 1:
raise TypeError, "update expected at most 1 arguments, got %d" % len(args)
if args:
other_dict = args[0]
if isinstance(other_dict, MultiValueDict):
for key, value_list in other_dict.lists():
self.setlistdefault(key, []).extend(value_list)
else:
try:
for key, value in other_dict.items():
self.setlistdefault(key, []).append(value)
except TypeError:
raise ValueError, "MultiValueDict.update() takes either a MultiValueDict or dictionary"
for key, value in kwargs.iteritems():
self.setlistdefault(key, []).append(value)
class DotExpandedDict(dict):
"""
A special dictionary constructor that takes a dictionary in which the keys
may contain dots to specify inner dictionaries. It's confusing, but this
example should make sense.
>>> d = DotExpandedDict({'person.1.firstname': ['Simon'], \
'person.1.lastname': ['Willison'], \
'person.2.firstname': ['Adrian'], \
'person.2.lastname': ['Holovaty']})
>>> d
{'person': {'1': {'lastname': ['Willison'], 'firstname': ['Simon']}, '2': {'lastname': ['Holovaty'], 'firstname': ['Adrian']}}}
>>> d['person']
{'1': {'lastname': ['Willison'], 'firstname': ['Simon']}, '2': {'lastname': ['Holovaty'], 'firstname': ['Adrian']}}
>>> d['person']['1']
{'lastname': ['Willison'], 'firstname': ['Simon']}
# Gotcha: Results are unpredictable if the dots are "uneven":
>>> DotExpandedDict({'c.1': 2, 'c.2': 3, 'c': 1})
{'c': 1}
"""
def __init__(self, key_to_list_mapping):
for k, v in key_to_list_mapping.items():
current = self
bits = k.split('.')
for bit in bits[:-1]:
current = current.setdefault(bit, {})
# Now assign value to current position
try:
current[bits[-1]] = v
except TypeError: # Special-case if current isn't a dict.
current = {bits[-1]: v}
class FileDict(dict):
"""
A dictionary used to hold uploaded file contents. The only special feature
here is that repr() of this object won't dump the entire contents of the
file to the output. A handy safeguard for a large file upload.
"""
def __repr__(self):
if 'content' in self:
d = dict(self, content='<omitted>')
return dict.__repr__(d)
return dict.__repr__(self)