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