• Language: en

Source code for django.utils.datastructures

import copy
import warnings
from collections import OrderedDict

from django.utils import six
from django.utils.deprecation import RemovedInDjango19Warning


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):
        warnings.warn('`MergeDict` is deprecated, use `dict.update()` '
                      'instead.', RemovedInDjango19Warning, 2)
        self.dicts = dicts

    def __bool__(self):
        return any(self.dicts)

    def __nonzero__(self):
        return type(self).__bool__(self)

    def __getitem__(self, key):
        for dict_ in self.dicts:
            try:
                return dict_[key]
            except KeyError:
                pass
        raise KeyError(key)

    def __copy__(self):
        return self.__class__(*self.dicts)

    def get(self, key, default=None):
        try:
            return self[key]
        except KeyError:
            return default

    # This is used by MergeDicts of MultiValueDicts.
    def getlist(self, key):
        for dict_ in self.dicts:
            if key in dict_:
                return dict_.getlist(key)
        return []

    def _iteritems(self):
        seen = set()
        for dict_ in self.dicts:
            for item in six.iteritems(dict_):
                k = item[0]
                if k in seen:
                    continue
                seen.add(k)
                yield item

    def _iterkeys(self):
        for k, v in self._iteritems():
            yield k

    def _itervalues(self):
        for k, v in self._iteritems():
            yield v

    if six.PY3:
        items = _iteritems
        keys = _iterkeys
        values = _itervalues
    else:
        iteritems = _iteritems
        iterkeys = _iterkeys
        itervalues = _itervalues

        def items(self):
            return list(self.iteritems())

        def keys(self):
            return list(self.iterkeys())

        def values(self):
            return list(self.itervalues())

    def has_key(self, key):
        for dict_ in self.dicts:
            if key in dict_:
                return True
        return False

    __contains__ = has_key

    __iter__ = _iterkeys

    def copy(self):
        """Returns a copy of this object."""
        return self.__copy__()

    def __str__(self):
        '''
        Returns something like

            "{'key1': 'val1', 'key2': 'val2', 'key3': 'val3'}"

        instead of the generic "<object meta-data>" inherited from object.
        '''
        return str(dict(self.items()))

    def __repr__(self):
        '''
        Returns something like

            MergeDict({'key1': 'val1', 'key2': 'val2'}, {'key3': 'val3'})

        instead of generic "<object meta-data>" inherited from object.
        '''
        dictreprs = ', '.join(repr(d) for d in self.dicts)
        return '%s(%s)' % (self.__class__.__name__, dictreprs)


[docs]class SortedDict(dict): """ A dictionary that keeps its keys in the order in which they're inserted. """ def __new__(cls, *args, **kwargs): instance = super(SortedDict, cls).__new__(cls, *args, **kwargs) instance.keyOrder = [] return instance def __init__(self, data=None): warnings.warn( "SortedDict is deprecated and will be removed in Django 1.9.", RemovedInDjango19Warning, stacklevel=2 ) if data is None or isinstance(data, dict): data = data or [] super(SortedDict, self).__init__(data) self.keyOrder = list(data) if data else [] else: super(SortedDict, self).__init__() super_set = super(SortedDict, self).__setitem__ for key, value in data: # Take the ordering from first key if key not in self: self.keyOrder.append(key) # But override with last value in data (dict() does this) super_set(key, value) def __deepcopy__(self, memo): return self.__class__([(key, copy.deepcopy(value, memo)) for key, value in self.items()]) def __copy__(self): # The Python's default copy implementation will alter the state # of self. The reason for this seems complex but is likely related to # subclassing dict. return self.copy() def __setitem__(self, key, value): if key not in self: self.keyOrder.append(key) super(SortedDict, self).__setitem__(key, value) def __delitem__(self, key): super(SortedDict, self).__delitem__(key) self.keyOrder.remove(key) def __iter__(self): return iter(self.keyOrder) def __reversed__(self): return reversed(self.keyOrder) 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 _iteritems(self): for key in self.keyOrder: yield key, self[key] def _iterkeys(self): for key in self.keyOrder: yield key def _itervalues(self): for key in self.keyOrder: yield self[key] if six.PY3: items = _iteritems keys = _iterkeys values = _itervalues else: iteritems = _iteritems iterkeys = _iterkeys itervalues = _itervalues def items(self): return [(k, self[k]) for k in self.keyOrder] def keys(self): return self.keyOrder[:] def values(self): return [self[k] for k in self.keyOrder] def update(self, dict_): for k, v in six.iteritems(dict_): self[k] = v def setdefault(self, key, default): if key not in self: self.keyOrder.append(key) return super(SortedDict, self).setdefault(key, default) def copy(self): """Returns a copy of this object.""" # This way of initializing the copy means it works for subclasses, too. return self.__class__(self) 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 six.iteritems(self)) def clear(self): super(SortedDict, self).clear() self.keyOrder = []
class OrderedSet(object): """ A set which keeps the ordering of the inserted items. Currently backs onto OrderedDict. """ def __init__(self, iterable=None): self.dict = OrderedDict(((x, None) for x in iterable) if iterable else []) def add(self, item): self.dict[item] = None def remove(self, item): del self.dict[item] def discard(self, item): try: self.remove(item) except KeyError: pass def __iter__(self): return iter(self.dict.keys()) def __contains__(self, item): return item in self.dict def __nonzero__(self): return bool(self.dict) 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.getlist('doesnotexist') [] >>> d.getlist('doesnotexist', ['Adrian', 'Simon']) ['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(repr(key)) try: return list_[-1] except IndexError: return [] def __setitem__(self, key, value): super(MultiValueDict, self).__setitem__(key, [value]) def __copy__(self): return self.__class__([ (k, v[:]) for k, v in self.lists() ]) def __deepcopy__(self, memo=None): 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 __getstate__(self): obj_dict = self.__dict__.copy() obj_dict['_data'] = dict((k, self.getlist(k)) for k in self) return obj_dict def __setstate__(self, obj_dict): data = obj_dict.pop('_data', {}) for k, v in data.items(): self.setlist(k, v) self.__dict__.update(obj_dict) 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, default=None): """ Returns the list of values for the passed key. If key doesn't exist, then a default value is returned. """ try: return super(MultiValueDict, self).__getitem__(key) except KeyError: if default is None: return [] return default 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 # Do not return default here because __setitem__() may store # another value -- QueryDict.__setitem__() does. Look it up. return self[key] def setlistdefault(self, key, default_list=None): if key not in self: if default_list is None: default_list = [] self.setlist(key, default_list) # Do not return default_list here because setlist() may store # another value -- QueryDict.setlist() does. Look it up. return self.getlist(key) def appendlist(self, key, value): """Appends an item to the internal list associated with key.""" self.setlistdefault(key).append(value) def _iteritems(self): """ Yields (key, value) pairs, where value is the last item in the list associated with the key. """ for key in self: yield key, self[key] def _iterlists(self): """Yields (key, list) pairs.""" return six.iteritems(super(MultiValueDict, self)) def _itervalues(self): """Yield the last value on every key list.""" for key in self: yield self[key] if six.PY3: items = _iteritems lists = _iterlists values = _itervalues else: iteritems = _iteritems iterlists = _iterlists itervalues = _itervalues def items(self): return list(self.iteritems()) def lists(self): return list(self.iterlists()) def values(self): return list(self.itervalues()) def copy(self): """Returns a shallow copy of this object.""" return copy.copy(self) 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 six.iteritems(kwargs): self.setlistdefault(key).append(value) def dict(self): """ Returns current object as a dict with singular values. """ return dict((key, self[key]) for key in self) class ImmutableList(tuple): """ A tuple-like object that raises useful errors when it is asked to mutate. Example:: >>> a = ImmutableList(range(5), warning="You cannot mutate this.") >>> a[3] = '4' Traceback (most recent call last): ... AttributeError: You cannot mutate this. """ def __new__(cls, *args, **kwargs): if 'warning' in kwargs: warning = kwargs['warning'] del kwargs['warning'] else: warning = 'ImmutableList object is immutable.' self = tuple.__new__(cls, *args, **kwargs) self.warning = warning return self def complain(self, *wargs, **kwargs): if isinstance(self.warning, Exception): raise self.warning else: raise AttributeError(self.warning) # All list mutation functions complain. __delitem__ = complain __delslice__ = complain __iadd__ = complain __imul__ = complain __setitem__ = complain __setslice__ = complain append = complain extend = complain insert = complain pop = complain remove = complain sort = complain reverse = complain class DictWrapper(dict): """ Wraps accesses to a dictionary so that certain values (those starting with the specified prefix) are passed through a function before being returned. The prefix is removed before looking up the real value. Used by the SQL construction code to ensure that values are correctly quoted before being used. """ def __init__(self, data, func, prefix): super(DictWrapper, self).__init__(data) self.func = func self.prefix = prefix def __getitem__(self, key): """ Retrieves the real value after stripping the prefix string (if present). If the prefix is present, pass the value through self.func before returning, otherwise return the raw value. """ if key.startswith(self.prefix): use_func = True key = key[len(self.prefix):] else: use_func = False value = super(DictWrapper, self).__getitem__(key) if use_func: return self.func(value) return value
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