359 lines
11 KiB
Python
359 lines
11 KiB
Python
"""
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Python Markdown
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A Python implementation of John Gruber's Markdown.
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Documentation: https://python-markdown.github.io/
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GitHub: https://github.com/Python-Markdown/markdown/
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PyPI: https://pypi.org/project/Markdown/
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Started by Manfred Stienstra (http://www.dwerg.net/).
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Maintained for a few years by Yuri Takhteyev (http://www.freewisdom.org).
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Currently maintained by Waylan Limberg (https://github.com/waylan),
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Dmitry Shachnev (https://github.com/mitya57) and Isaac Muse (https://github.com/facelessuser).
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Copyright 2007-2018 The Python Markdown Project (v. 1.7 and later)
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Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
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Copyright 2004 Manfred Stienstra (the original version)
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License: BSD (see LICENSE.md for details).
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"""
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import re
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import sys
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import warnings
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from collections import namedtuple
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from functools import wraps, lru_cache
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from itertools import count
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"""
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Constants you might want to modify
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-----------------------------------------------------------------------------
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"""
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BLOCK_LEVEL_ELEMENTS = [
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# Elements which are invalid to wrap in a `<p>` tag.
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# See https://w3c.github.io/html/grouping-content.html#the-p-element
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'address', 'article', 'aside', 'blockquote', 'details', 'div', 'dl',
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'fieldset', 'figcaption', 'figure', 'footer', 'form', 'h1', 'h2', 'h3',
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'h4', 'h5', 'h6', 'header', 'hgroup', 'hr', 'main', 'menu', 'nav', 'ol',
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'p', 'pre', 'section', 'table', 'ul',
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# Other elements which Markdown should not be mucking up the contents of.
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'canvas', 'colgroup', 'dd', 'body', 'dt', 'group', 'html', 'iframe', 'li', 'legend',
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'math', 'map', 'noscript', 'output', 'object', 'option', 'progress', 'script',
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'style', 'summary', 'tbody', 'td', 'textarea', 'tfoot', 'th', 'thead', 'tr', 'video'
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]
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# Placeholders
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STX = '\u0002' # Use `STX` ("Start of text") for start-of-placeholder
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ETX = '\u0003' # Use `ETX` ("End of text") for end-of-placeholder
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INLINE_PLACEHOLDER_PREFIX = STX+"klzzwxh:"
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INLINE_PLACEHOLDER = INLINE_PLACEHOLDER_PREFIX + "%s" + ETX
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INLINE_PLACEHOLDER_RE = re.compile(INLINE_PLACEHOLDER % r'([0-9]+)')
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AMP_SUBSTITUTE = STX+"amp"+ETX
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HTML_PLACEHOLDER = STX + "wzxhzdk:%s" + ETX
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HTML_PLACEHOLDER_RE = re.compile(HTML_PLACEHOLDER % r'([0-9]+)')
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TAG_PLACEHOLDER = STX + "hzzhzkh:%s" + ETX
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"""
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Constants you probably do not need to change
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-----------------------------------------------------------------------------
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"""
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RTL_BIDI_RANGES = (
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('\u0590', '\u07FF'),
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# Hebrew (0590-05FF), Arabic (0600-06FF),
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# Syriac (0700-074F), Arabic supplement (0750-077F),
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# Thaana (0780-07BF), Nko (07C0-07FF).
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('\u2D30', '\u2D7F') # Tifinagh
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)
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"""
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AUXILIARY GLOBAL FUNCTIONS
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=============================================================================
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"""
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@lru_cache(maxsize=None)
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def get_installed_extensions():
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if sys.version_info >= (3, 10):
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from importlib import metadata
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else: # `<PY310` use backport
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import importlib_metadata as metadata
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# Only load extension entry_points once.
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return metadata.entry_points(group='markdown.extensions')
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def deprecated(message, stacklevel=2):
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"""
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Raise a `DeprecationWarning` when wrapped function/method is called.
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Usage:
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@deprecated("This method will be removed in version X; use Y instead.")
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def some_method()"
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pass
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"""
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def wrapper(func):
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@wraps(func)
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def deprecated_func(*args, **kwargs):
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warnings.warn(
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f"'{func.__name__}' is deprecated. {message}",
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category=DeprecationWarning,
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stacklevel=stacklevel
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)
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return func(*args, **kwargs)
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return deprecated_func
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return wrapper
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def parseBoolValue(value, fail_on_errors=True, preserve_none=False):
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"""Parses a string representing boolean value. If parsing was successful,
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returns True or False. If `preserve_none=True`, returns `True`, `False`,
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or `None`. If parsing was not successful, raises `ValueError`, or, if
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`fail_on_errors=False`, returns `None`."""
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if not isinstance(value, str):
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if preserve_none and value is None:
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return value
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return bool(value)
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elif preserve_none and value.lower() == 'none':
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return None
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elif value.lower() in ('true', 'yes', 'y', 'on', '1'):
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return True
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elif value.lower() in ('false', 'no', 'n', 'off', '0', 'none'):
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return False
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elif fail_on_errors:
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raise ValueError('Cannot parse bool value: %r' % value)
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def code_escape(text):
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"""Escape code."""
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if "&" in text:
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text = text.replace("&", "&")
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if "<" in text:
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text = text.replace("<", "<")
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if ">" in text:
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text = text.replace(">", ">")
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return text
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def _get_stack_depth(size=2):
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"""Get current stack depth, performantly.
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"""
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frame = sys._getframe(size)
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for size in count(size):
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frame = frame.f_back
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if not frame:
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return size
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def nearing_recursion_limit():
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"""Return true if current stack depth is within 100 of maximum limit."""
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return sys.getrecursionlimit() - _get_stack_depth() < 100
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"""
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MISC AUXILIARY CLASSES
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=============================================================================
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"""
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class AtomicString(str):
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"""A string which should not be further processed."""
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pass
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class Processor:
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def __init__(self, md=None):
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self.md = md
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class HtmlStash:
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"""
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This class is used for stashing HTML objects that we extract
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in the beginning and replace with place-holders.
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"""
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def __init__(self):
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""" Create an `HtmlStash`. """
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self.html_counter = 0 # for counting inline html segments
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self.rawHtmlBlocks = []
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self.tag_counter = 0
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self.tag_data = [] # list of dictionaries in the order tags appear
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def store(self, html):
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"""
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Saves an HTML segment for later reinsertion. Returns a
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placeholder string that needs to be inserted into the
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document.
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Keyword arguments:
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* `html`: an html segment
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Returns : a placeholder string
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"""
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self.rawHtmlBlocks.append(html)
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placeholder = self.get_placeholder(self.html_counter)
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self.html_counter += 1
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return placeholder
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def reset(self):
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self.html_counter = 0
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self.rawHtmlBlocks = []
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def get_placeholder(self, key):
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return HTML_PLACEHOLDER % key
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def store_tag(self, tag, attrs, left_index, right_index):
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"""Store tag data and return a placeholder."""
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self.tag_data.append({'tag': tag, 'attrs': attrs,
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'left_index': left_index,
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'right_index': right_index})
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placeholder = TAG_PLACEHOLDER % str(self.tag_counter)
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self.tag_counter += 1 # equal to the tag's index in `self.tag_data`
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return placeholder
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# Used internally by `Registry` for each item in its sorted list.
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# Provides an easier to read API when editing the code later.
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# For example, `item.name` is more clear than `item[0]`.
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_PriorityItem = namedtuple('PriorityItem', ['name', 'priority'])
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class Registry:
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"""
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A priority sorted registry.
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A `Registry` instance provides two public methods to alter the data of the
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registry: `register` and `deregister`. Use `register` to add items and
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`deregister` to remove items. See each method for specifics.
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When registering an item, a "name" and a "priority" must be provided. All
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items are automatically sorted by "priority" from highest to lowest. The
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"name" is used to remove ("deregister") and get items.
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A `Registry` instance it like a list (which maintains order) when reading
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data. You may iterate over the items, get an item and get a count (length)
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of all items. You may also check that the registry contains an item.
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When getting an item you may use either the index of the item or the
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string-based "name". For example:
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registry = Registry()
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registry.register(SomeItem(), 'itemname', 20)
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# Get the item by index
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item = registry[0]
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# Get the item by name
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item = registry['itemname']
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When checking that the registry contains an item, you may use either the
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string-based "name", or a reference to the actual item. For example:
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someitem = SomeItem()
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registry.register(someitem, 'itemname', 20)
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# Contains the name
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assert 'itemname' in registry
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# Contains the item instance
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assert someitem in registry
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The method `get_index_for_name` is also available to obtain the index of
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an item using that item's assigned "name".
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"""
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def __init__(self):
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self._data = {}
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self._priority = []
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self._is_sorted = False
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def __contains__(self, item):
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if isinstance(item, str):
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# Check if an item exists by this name.
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return item in self._data.keys()
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# Check if this instance exists.
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return item in self._data.values()
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def __iter__(self):
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self._sort()
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return iter([self._data[k] for k, p in self._priority])
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def __getitem__(self, key):
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self._sort()
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if isinstance(key, slice):
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data = Registry()
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for k, p in self._priority[key]:
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data.register(self._data[k], k, p)
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return data
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if isinstance(key, int):
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return self._data[self._priority[key].name]
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return self._data[key]
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def __len__(self):
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return len(self._priority)
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def __repr__(self):
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return '<{}({})>'.format(self.__class__.__name__, list(self))
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def get_index_for_name(self, name):
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"""
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Return the index of the given name.
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"""
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if name in self:
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self._sort()
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return self._priority.index(
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[x for x in self._priority if x.name == name][0]
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)
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raise ValueError('No item named "{}" exists.'.format(name))
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def register(self, item, name, priority):
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"""
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Add an item to the registry with the given name and priority.
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Parameters:
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* `item`: The item being registered.
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* `name`: A string used to reference the item.
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* `priority`: An integer or float used to sort against all items.
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If an item is registered with a "name" which already exists, the
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existing item is replaced with the new item. Treat carefully as the
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old item is lost with no way to recover it. The new item will be
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sorted according to its priority and will **not** retain the position
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of the old item.
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"""
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if name in self:
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# Remove existing item of same name first
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self.deregister(name)
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self._is_sorted = False
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self._data[name] = item
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self._priority.append(_PriorityItem(name, priority))
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def deregister(self, name, strict=True):
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"""
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Remove an item from the registry.
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Set `strict=False` to fail silently.
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"""
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try:
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index = self.get_index_for_name(name)
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del self._priority[index]
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del self._data[name]
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except ValueError:
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if strict:
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raise
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def _sort(self):
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"""
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Sort the registry by priority from highest to lowest.
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This method is called internally and should never be explicitly called.
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"""
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if not self._is_sorted:
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self._priority.sort(key=lambda item: item.priority, reverse=True)
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self._is_sorted = True
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