61 lines
1.9 KiB
Python
61 lines
1.9 KiB
Python
# Copyright (c) 2012 The Chromium Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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'''Utility to remove comments from JSON files so that they can be parsed by
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json.loads.
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'''
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def _Rcount(string, chars):
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'''Returns the number of consecutive characters from |chars| that occur at the
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end of |string|.
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'''
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return len(string) - len(string.rstrip(chars))
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def _FindNextToken(string, tokens, start):
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'''Finds the next token in |tokens| that occurs in |string| from |start|.
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Returns a tuple (index, token key).
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'''
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min_index, min_key = (-1, None)
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for k in tokens:
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index = string.find(k, start)
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if index != -1 and (min_index == -1 or index < min_index):
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min_index, min_key = (index, k)
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return (min_index, min_key)
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def _ReadString(input, start, output):
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output.append('"')
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start_range, end_range = (start, input.find('"', start))
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# \" escapes the ", \\" doesn't, \\\" does, etc.
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while (end_range != -1 and
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_Rcount(input[start_range:end_range], '\\') % 2 == 1):
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start_range, end_range = (end_range, input.find('"', end_range + 1))
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if end_range == -1:
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return start_range + 1
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output.append(input[start:end_range + 1])
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return end_range + 1
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def _ReadComment(input, start, output):
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eol_tokens = ('\n', '\r')
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eol_token_index, eol_token = _FindNextToken(input, eol_tokens, start)
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if eol_token is None:
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return len(input)
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output.append(eol_token)
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return eol_token_index + len(eol_token)
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def Nom(input):
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token_actions = {
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'"': _ReadString,
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'//': _ReadComment,
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}
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output = []
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pos = 0
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while pos < len(input):
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token_index, token = _FindNextToken(input, token_actions.keys(), pos)
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if token is None:
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output.append(input[pos:])
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break
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output.append(input[pos:token_index])
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pos = token_actions[token](input, token_index + len(token), output)
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return ''.join(output)
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