127 lines
4.0 KiB
Python
127 lines
4.0 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2012 OpenStack LLC.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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class ParseError(Exception):
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def __init__(self, message, lineno, line):
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self.msg = message
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self.line = line
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self.lineno = lineno
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def __str__(self):
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return 'at line %d, %s: %r' % (self.lineno, self.msg, self.line)
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class BaseParser(object):
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lineno = 0
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parse_exc = ParseError
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def _assignment(self, key, value):
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self.assignment(key, value)
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return None, []
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def _get_section(self, line):
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if line[-1] != ']':
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return self.error_no_section_end_bracket(line)
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if len(line) <= 2:
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return self.error_no_section_name(line)
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return line[1:-1]
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def _split_key_value(self, line):
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colon = line.find(':')
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equal = line.find('=')
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if colon < 0 and equal < 0:
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return self.error_invalid_assignment(line)
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if colon < 0 or (equal >= 0 and equal < colon):
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key, value = line[:equal], line[equal + 1:]
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else:
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key, value = line[:colon], line[colon + 1:]
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return key.strip(), [value.strip()]
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def parse(self, lineiter):
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key = None
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value = []
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for line in lineiter:
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self.lineno += 1
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line = line.rstrip()
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if not line:
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# Blank line, ends multi-line values
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if key:
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key, value = self._assignment(key, value)
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continue
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elif line[0] in (' ', '\t'):
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# Continuation of previous assignment
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if key is None:
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self.error_unexpected_continuation(line)
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else:
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value.append(line.lstrip())
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continue
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if key:
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# Flush previous assignment, if any
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key, value = self._assignment(key, value)
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if line[0] == '[':
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# Section start
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section = self._get_section(line)
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if section:
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self.new_section(section)
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elif line[0] in '#;':
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self.comment(line[1:].lstrip())
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else:
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key, value = self._split_key_value(line)
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if not key:
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return self.error_empty_key(line)
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if key:
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# Flush previous assignment, if any
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self._assignment(key, value)
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def assignment(self, key, value):
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"""Called when a full assignment is parsed"""
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raise NotImplementedError()
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def new_section(self, section):
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"""Called when a new section is started"""
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raise NotImplementedError()
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def comment(self, comment):
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"""Called when a comment is parsed"""
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pass
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def error_invalid_assignment(self, line):
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raise self.parse_exc("No ':' or '=' found in assignment",
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self.lineno, line)
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def error_empty_key(self, line):
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raise self.parse_exc('Key cannot be empty', self.lineno, line)
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def error_unexpected_continuation(self, line):
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raise self.parse_exc('Unexpected continuation line',
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self.lineno, line)
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def error_no_section_end_bracket(self, line):
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raise self.parse_exc('Invalid section (must end with ])',
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self.lineno, line)
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def error_no_section_name(self, line):
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raise self.parse_exc('Empty section name', self.lineno, line)
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