linkchecker/linkcheck/containers.py

282 lines
8.8 KiB
Python

# -*- coding: iso-8859-1 -*-
# Copyright (C) 2004-2014 Bastian Kleineidam
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""
Special container classes.
"""
from collections import namedtuple
class AttrDict (dict):
"""Dictionary allowing attribute access to its elements if they
are valid attribute names and not already existing methods."""
def __getattr__ (self, name):
"""Return attribute name from dict."""
return self[name]
class ListDict (dict):
"""A dictionary whose iterators reflect the order in which elements
were added.
"""
def __init__ (self):
"""Initialize sorted key list."""
super(ListDict, self).__init__()
# sorted list of keys
self._keys = []
def setdefault (self, key, *args):
"""Remember key order if key not found."""
if key not in self:
self._keys.append(key)
return super(ListDict, self).setdefault(key, *args)
def __setitem__ (self, key, value):
"""Add key,value to dict, append key to sorted list."""
if key not in self:
self._keys.append(key)
super(ListDict, self).__setitem__(key, value)
def __delitem__ (self, key):
"""Remove key from dict."""
self._keys.remove(key)
super(ListDict, self).__delitem__(key)
def pop (self, key):
"""Remove key from dict and return value."""
if key in self._keys:
self._keys.remove(key)
super(ListDict, self).pop(key)
def popitem (self):
"""Remove oldest key from dict and return item."""
if self._keys:
k = self._keys[0]
v = self[k]
del self[k]
return (k, v)
raise KeyError("popitem() on empty dictionary")
def values (self):
"""Return sorted list of values."""
return [self[k] for k in self._keys]
def items (self):
"""Return sorted list of items."""
return [(k, self[k]) for k in self._keys]
def keys (self):
"""Return sorted list of keys."""
return self._keys[:]
def itervalues (self):
"""Return iterator over sorted values."""
for k in self._keys:
yield self[k]
def iteritems (self):
"""Return iterator over sorted items."""
for k in self._keys:
yield (k, self[k])
def iterkeys (self):
"""Return iterator over sorted keys."""
return iter(self._keys)
def clear (self):
"""Remove all dict entries."""
self._keys = []
super(ListDict, self).clear()
def get_true (self, key, default):
"""Return default element if key is not in the dict, or if self[key]
evaluates to False. Useful for example if value is None, but
default value should be an empty string.
"""
if key not in self or not self[key]:
return default
return self[key]
class CaselessDict (dict):
"""A dictionary ignoring the case of keys (which must be strings)."""
def __getitem__ (self, key):
"""Return lowercase key item."""
assert isinstance(key, basestring)
return dict.__getitem__(self, key.lower())
def __delitem__ (self, key):
"""Remove lowercase key item."""
assert isinstance(key, basestring)
return dict.__delitem__(self, key.lower())
def __setitem__ (self, key, value):
"""Set lowercase key item."""
assert isinstance(key, basestring)
dict.__setitem__(self, key.lower(), value)
def __contains__ (self, key):
"""Check lowercase key item."""
assert isinstance(key, basestring)
return dict.__contains__(self, key.lower())
def get (self, key, def_val=None):
"""Return lowercase key value."""
assert isinstance(key, basestring)
return dict.get(self, key.lower(), def_val)
def setdefault (self, key, *args):
"""Set lowercase key value and return."""
assert isinstance(key, basestring)
return dict.setdefault(self, key.lower(), *args)
def update (self, other):
"""Update this dict with lowercase key from other dict"""
for k, v in other.items():
dict.__setitem__(self, k.lower(), v)
def fromkeys (cls, iterable, value=None):
"""Construct new caseless dict from given data."""
d = cls()
for k in iterable:
dict.__setitem__(d, k.lower(), value)
return d
fromkeys = classmethod(fromkeys)
def pop (self, key, *args):
"""Remove lowercase key from dict and return value."""
assert isinstance(key, basestring)
return dict.pop(self, key.lower(), *args)
class CaselessSortedDict (CaselessDict):
"""Caseless dictionary with sorted keys."""
def keys (self):
"""Return sorted key list."""
return sorted(super(CaselessSortedDict, self).keys())
def items (self):
"""Return sorted item list."""
return [(x, self[x]) for x in self.keys()]
def iteritems (self):
"""Return sorted item iterator."""
return ((x, self[x]) for x in self.keys())
class LFUCache (dict):
"""Limited cache which purges least frequently used items."""
def __init__ (self, size=1000):
"""Initialize internal LFU cache."""
super(LFUCache, self).__init__()
if size < 1:
raise ValueError("invalid cache size %d" % size)
self.size = size
def __setitem__ (self, key, val):
"""Store given key/value."""
if key in self:
# store value, do not increase number of uses
super(LFUCache, self).__getitem__(key)[1] = val
else:
super(LFUCache, self).__setitem__(key, [0, val])
# check for size limit
if len(self) > self.size:
self.shrink()
def shrink (self):
"""Shrink ca. 5% of entries."""
trim = int(0.05*len(self))
if trim:
items = super(LFUCache, self).items()
# sorting function for items
keyfunc = lambda x: x[1][0]
values = sorted(items, key=keyfunc)
for item in values[0:trim]:
del self[item[0]]
def __getitem__ (self, key):
"""Update key usage and return value."""
entry = super(LFUCache, self).__getitem__(key)
entry[0] += 1
return entry[1]
def uses (self, key):
"""Get number of uses for given key (without increasing the number of
uses)"""
return super(LFUCache, self).__getitem__(key)[0]
def get (self, key, def_val=None):
"""Update key usage if found and return value, else return default."""
if key in self:
return self[key]
return def_val
def setdefault (self, key, def_val=None):
"""Update key usage if found and return value, else set and return
default."""
if key in self:
return self[key]
self[key] = def_val
return def_val
def items (self):
"""Return list of items, not updating usage count."""
return [(key, value[1]) for key, value in super(LFUCache, self).items()]
def iteritems (self):
"""Return iterator of items, not updating usage count."""
for key, value in super(LFUCache, self).items():
yield (key, value[1])
def values (self):
"""Return list of values, not updating usage count."""
return [value[1] for value in super(LFUCache, self).values()]
def itervalues (self):
"""Return iterator of values, not updating usage count."""
for value in super(LFUCache, self).values():
yield value[1]
def popitem (self):
"""Remove and return an item."""
key, value = super(LFUCache, self).popitem()
return (key, value[1])
def pop (self):
"""Remove and return a value."""
value = super(LFUCache, self).pop()
return value[1]
def enum (*names):
"""Return an enum datatype instance from given list of keyword names.
The enum values are zero-based integers.
>>> Status = enum('open', 'pending', 'closed')
>>> Status.open
0
>>> Status.pending
1
>>> Status.closed
2
"""
return namedtuple('Enum', ' '.join(names))(*range(len(names)))