133 lines
4.1 KiB
Python
133 lines
4.1 KiB
Python
# Copyright (c) 2024 Síle Ekaterin Liszka
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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'''
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Utility functions for saving data in XBC format.
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'''
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import re
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from collections.abc import Sequence, Mapping
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KEY_RE = re.compile(r'^[a-zA-Z0-9_-]+(?:\.(?:[a-zA-Z0-9_-]+))*$')
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NVAL_RE = re.compile(r'^[^{}=+:;,\n\'"]+$')
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QUOTES = '\'"'
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QUOTEMAP = {'"': "'", "'": '"'}
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ESCAPES = {
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'backslash': {'"': '\\x22', "'": '\\x27'},
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'html': {'"': '"', "'": '''},
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'url': {'"': '%22', "'": '%27'}
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}
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def quote(data, escape='backslash'):
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'Quote data according to XBC rules.'
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# don't waste our time if it's a valid bare value.
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if NVAL_RE.match(data) is not None:
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return data
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esc = None
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# how shall we escape embedded quotes?
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if isinstance(esc, Mapping):
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if '"' in escape and "'" in escape:
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esc = escape
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else:
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esc = ESCAPES.get(escape, None)
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if esc is None:
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raise ValueError('unrecognised escape format')
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f = data[0]
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# is this a quoted string?
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if f in QUOTES and data[-1] == f:
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# return it if we don't need to do anything
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if f not in data[1:-1]:
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return data
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# escape embedded quotes
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x = data[1:-1].replace(f, esc[f])
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return f'{f}{x}{f}'
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# if the other quote isn't used, wrap in it
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if f in QUOTES and QUOTEMAP[f] not in data[1:]:
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q = QUOTEMAP[f]
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# not a quoted string, but has only one kind of quote
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elif "'" in data and '"' not in data:
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q = '"'
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elif '"' in data and "'" not in data:
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q = "'"
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else:
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# not a quoted string and has both types; we escape one
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data = data.replace("'", esc["'"])
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q = "'"
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return f'{q}{data}{q}'
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def normalise_string(string):
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'Normalise values according to XBC rules.'
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if not isinstance(string, str):
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string = str(string)
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if NVAL_RE.match(string) is None:
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string = quote(string)
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return string
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def normalise(data):
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'''Normalise values according to XBC rules.'''
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if isinstance(data, str) or not isinstance(data, (Sequence, Mapping)):
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return normalise_string(data)
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if isinstance(data, Sequence):
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ret = []
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for item in data:
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if isinstance(item, str) or not isinstance(item, (Sequence, Mapping)):
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ret.append(normalise_string(item))
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# we can unwind nested sequences
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elif isinstance(item, Sequence):
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ret.extend(normalise(item))
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# ...but we can't do that with mappings, the format doesn't
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# support it.
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elif isinstance(item, Mapping):
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raise ValueError('nested mapping')
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else:
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# this should be impossible to reach, but nothing truly is.
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raise ValueError(type(item))
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ret = ', '.join(ret)
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return ret
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if isinstance(data, Mapping):
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d = {}
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for k, v in data.items():
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if KEY_RE.match(k) is None:
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raise KeyError(k)
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v = normalise(v)
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d[k] = v
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return d
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return data
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__all__ = ['quote', 'normalise', 'normalise_string']
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