Source code for mwparserfromhell.smart_list

# -*- coding: utf-8  -*-
#
# Copyright (C) 2012-2016 Ben Kurtovic <ben.kurtovic@gmail.com>
#
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# of this software and associated documentation files (the "Software"), to deal
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# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# SOFTWARE.

"""
This module contains the :class:`.SmartList` type, as well as its
:class:`._ListProxy` child, which together implement a list whose sublists
reflect changes made to the main list, and vice-versa.
"""

from __future__ import unicode_literals
from sys import maxsize
from weakref import ref

from .compat import py3k

__all__ = ["SmartList"]

def inheritdoc(method):
    """Set __doc__ of *method* to __doc__ of *method* in its parent class.

    Since this is used on :class:`.SmartList`, the "parent class" used is
    ``list``. This function can be used as a decorator.
    """
    method.__doc__ = getattr(list, method.__name__).__doc__
    return method


class _SliceNormalizerMixIn(object):
    """MixIn that provides a private method to normalize slices."""

    def _normalize_slice(self, key, clamp=False):
        """Return a slice equivalent to the input *key*, standardized."""
        if key.start is None:
            start = 0
        else:
            start = (len(self) + key.start) if key.start < 0 else key.start
        if key.stop is None or key.stop == maxsize:
            stop = len(self) if clamp else None
        else:
            stop = (len(self) + key.stop) if key.stop < 0 else key.stop
        return slice(start, stop, key.step or 1)


[docs]class SmartList(_SliceNormalizerMixIn, list): """Implements the ``list`` interface with special handling of sublists. When a sublist is created (by ``list[i:j]``), any changes made to this list (such as the addition, removal, or replacement of elements) will be reflected in the sublist, or vice-versa, to the greatest degree possible. This is implemented by having sublists - instances of the :class:`._ListProxy` type - dynamically determine their elements by storing their slice info and retrieving that slice from the parent. Methods that change the size of the list also change the slice info. For example:: >>> parent = SmartList([0, 1, 2, 3]) >>> parent [0, 1, 2, 3] >>> child = parent[2:] >>> child [2, 3] >>> child.append(4) >>> child [2, 3, 4] >>> parent [0, 1, 2, 3, 4] """ def __init__(self, iterable=None): if iterable: super(SmartList, self).__init__(iterable) else: super(SmartList, self).__init__() self._children = {} def __getitem__(self, key): if not isinstance(key, slice): return super(SmartList, self).__getitem__(key) key = self._normalize_slice(key, clamp=False) sliceinfo = [key.start, key.stop, key.step] child = _ListProxy(self, sliceinfo) child_ref = ref(child, self._delete_child) self._children[id(child_ref)] = (child_ref, sliceinfo) return child def __setitem__(self, key, item): if not isinstance(key, slice): return super(SmartList, self).__setitem__(key, item) item = list(item) super(SmartList, self).__setitem__(key, item) key = self._normalize_slice(key, clamp=True) diff = len(item) + (key.start - key.stop) // key.step if not diff: return values = self._children.values if py3k else self._children.itervalues for child, (start, stop, step) in values(): if start > key.stop: self._children[id(child)][1][0] += diff if stop is not None and stop >= key.stop: self._children[id(child)][1][1] += diff def __delitem__(self, key): super(SmartList, self).__delitem__(key) if isinstance(key, slice): key = self._normalize_slice(key, clamp=True) else: key = slice(key, key + 1, 1) diff = (key.stop - key.start) // key.step values = self._children.values if py3k else self._children.itervalues for child, (start, stop, step) in values(): if start > key.start: self._children[id(child)][1][0] -= diff if stop is not None and stop >= key.stop: self._children[id(child)][1][1] -= diff if not py3k: def __getslice__(self, start, stop): return self.__getitem__(slice(start, stop)) def __setslice__(self, start, stop, iterable): self.__setitem__(slice(start, stop), iterable) def __delslice__(self, start, stop): self.__delitem__(slice(start, stop)) def __add__(self, other): return SmartList(list(self) + other) def __radd__(self, other): return SmartList(other + list(self)) def __iadd__(self, other): self.extend(other) return self def _delete_child(self, child_ref): """Remove a child reference that is about to be garbage-collected.""" del self._children[id(child_ref)] def _detach_children(self): """Remove all children and give them independent parent copies.""" children = [val[0] for val in self._children.values()] for child in children: child()._parent = list(self) self._children.clear() @inheritdoc
[docs] def append(self, item): head = len(self) self[head:head] = [item]
@inheritdoc
[docs] def extend(self, item): head = len(self) self[head:head] = item
@inheritdoc
[docs] def insert(self, index, item): self[index:index] = [item]
@inheritdoc
[docs] def pop(self, index=None): if index is None: index = len(self) - 1 item = self[index] del self[index] return item
@inheritdoc
[docs] def remove(self, item): del self[self.index(item)]
@inheritdoc
[docs] def reverse(self): self._detach_children() super(SmartList, self).reverse()
if py3k: @inheritdoc def sort(self, key=None, reverse=None): self._detach_children() kwargs = {} if key is not None: kwargs["key"] = key if reverse is not None: kwargs["reverse"] = reverse super(SmartList, self).sort(**kwargs) else: @inheritdoc
[docs] def sort(self, cmp=None, key=None, reverse=None): self._detach_children() kwargs = {} if cmp is not None: kwargs["cmp"] = cmp if key is not None: kwargs["key"] = key if reverse is not None: kwargs["reverse"] = reverse super(SmartList, self).sort(**kwargs)
[docs]class _ListProxy(_SliceNormalizerMixIn, list): """Implement the ``list`` interface by getting elements from a parent. This is created by a :class:`.SmartList` object when slicing. It does not actually store the list at any time; instead, whenever the list is needed, it builds it dynamically using the :meth:`_render` method. """ def __init__(self, parent, sliceinfo): super(_ListProxy, self).__init__() self._parent = parent self._sliceinfo = sliceinfo def __repr__(self): return repr(self._render()) def __lt__(self, other): if isinstance(other, _ListProxy): return self._render() < list(other) return self._render() < other def __le__(self, other): if isinstance(other, _ListProxy): return self._render() <= list(other) return self._render() <= other def __eq__(self, other): if isinstance(other, _ListProxy): return self._render() == list(other) return self._render() == other def __ne__(self, other): if isinstance(other, _ListProxy): return self._render() != list(other) return self._render() != other def __gt__(self, other): if isinstance(other, _ListProxy): return self._render() > list(other) return self._render() > other def __ge__(self, other): if isinstance(other, _ListProxy): return self._render() >= list(other) return self._render() >= other if py3k: def __bool__(self): return bool(self._render()) else: def __nonzero__(self): return bool(self._render()) def __len__(self): return max((self._stop - self._start) // self._step, 0) def __getitem__(self, key): if isinstance(key, slice): key = self._normalize_slice(key, clamp=True) keystart = min(self._start + key.start, self._stop) keystop = min(self._start + key.stop, self._stop) adjusted = slice(keystart, keystop, key.step) return self._parent[adjusted] else: return self._render()[key] def __setitem__(self, key, item): if isinstance(key, slice): key = self._normalize_slice(key, clamp=True) keystart = min(self._start + key.start, self._stop) keystop = min(self._start + key.stop, self._stop) adjusted = slice(keystart, keystop, key.step) self._parent[adjusted] = item else: length = len(self) if key < 0: key = length + key if key < 0 or key >= length: raise IndexError("list assignment index out of range") self._parent[self._start + key] = item def __delitem__(self, key): if isinstance(key, slice): key = self._normalize_slice(key, clamp=True) keystart = min(self._start + key.start, self._stop) keystop = min(self._start + key.stop, self._stop) adjusted = slice(keystart, keystop, key.step) del self._parent[adjusted] else: length = len(self) if key < 0: key = length + key if key < 0 or key >= length: raise IndexError("list assignment index out of range") del self._parent[self._start + key] def __iter__(self): i = self._start while i < self._stop: yield self._parent[i] i += self._step def __reversed__(self): i = self._stop - 1 while i >= self._start: yield self._parent[i] i -= self._step def __contains__(self, item): return item in self._render() if not py3k: def __getslice__(self, start, stop): return self.__getitem__(slice(start, stop)) def __setslice__(self, start, stop, iterable): self.__setitem__(slice(start, stop), iterable) def __delslice__(self, start, stop): self.__delitem__(slice(start, stop)) def __add__(self, other): return SmartList(list(self) + other) def __radd__(self, other): return SmartList(other + list(self)) def __iadd__(self, other): self.extend(other) return self def __mul__(self, other): return SmartList(list(self) * other) def __rmul__(self, other): return SmartList(other * list(self)) def __imul__(self, other): self.extend(list(self) * (other - 1)) return self @property def _start(self): """The starting index of this list, inclusive.""" return self._sliceinfo[0] @property def _stop(self): """The ending index of this list, exclusive.""" if self._sliceinfo[1] is None: return len(self._parent) return self._sliceinfo[1] @property def _step(self): """The number to increase the index by between items.""" return self._sliceinfo[2] def _render(self): """Return the actual list from the stored start/stop/step.""" return list(self._parent)[self._start:self._stop:self._step] @inheritdoc
[docs] def append(self, item): self._parent.insert(self._stop, item)
@inheritdoc
[docs] def count(self, item): return self._render().count(item)
@inheritdoc
[docs] def index(self, item, start=None, stop=None): if start is not None: if stop is not None: return self._render().index(item, start, stop) return self._render().index(item, start) return self._render().index(item)
@inheritdoc
[docs] def extend(self, item): self._parent[self._stop:self._stop] = item
@inheritdoc
[docs] def insert(self, index, item): if index < 0: index = len(self) + index self._parent.insert(self._start + index, item)
@inheritdoc
[docs] def pop(self, index=None): length = len(self) if index is None: index = length - 1 elif index < 0: index = length + index if index < 0 or index >= length: raise IndexError("pop index out of range") return self._parent.pop(self._start + index)
@inheritdoc
[docs] def remove(self, item): index = self.index(item) del self._parent[self._start + index]
@inheritdoc
[docs] def reverse(self): item = self._render() item.reverse() self._parent[self._start:self._stop:self._step] = item
if py3k: @inheritdoc def sort(self, key=None, reverse=None): item = self._render() kwargs = {} if key is not None: kwargs["key"] = key if reverse is not None: kwargs["reverse"] = reverse item.sort(**kwargs) self._parent[self._start:self._stop:self._step] = item else: @inheritdoc
[docs] def sort(self, cmp=None, key=None, reverse=None): item = self._render() kwargs = {} if cmp is not None: kwargs["cmp"] = cmp if key is not None: kwargs["key"] = key if reverse is not None: kwargs["reverse"] = reverse item.sort(**kwargs) self._parent[self._start:self._stop:self._step] = item
del inheritdoc