89 lines
3.2 KiB
Python
89 lines
3.2 KiB
Python
from __future__ import absolute_import, unicode_literals
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import re
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from mopidy.mpd import exceptions
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WORD_RE = re.compile(r"""
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^
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(\s*) # Leading whitespace not allowed, capture it to report.
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([a-z][a-z0-9_]*) # A command name
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(?:\s+|$) # trailing whitespace or EOS
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(.*) # Possibly a remainder to be parsed
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""", re.VERBOSE)
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# Quotes matching is an unrolled version of "(?:[^"\\]|\\.)*"
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PARAM_RE = re.compile(r"""
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^ # Leading whitespace is not allowed
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(?:
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([^%(unprintable)s"']+) # ord(char) < 0x20, not ", not '
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| # or
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"([^"\\]*(?:\\.[^"\\]*)*)" # anything surrounded by quotes
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)
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(?:\s+|$) # trailing whitespace or EOS
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(.*) # Possibly a remainder to be parsed
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""" % {'unprintable': ''.join(map(chr, range(0x21)))}, re.VERBOSE)
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BAD_QUOTED_PARAM_RE = re.compile(r"""
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^
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"[^"\\]*(?:\\.[^"\\]*)* # start of a quoted value
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(?: # followed by:
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("[^\s]) # non-escaped quote, followed by non-whitespace
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| # or
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([^"]) # anything that is not a quote
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)
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""", re.VERBOSE)
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UNESCAPE_RE = re.compile(r'\\(.)') # Backslash escapes any following char.
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def split(line):
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"""Splits a line into tokens using same rules as MPD.
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- Lines may not start with whitespace
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- Tokens are split by arbitrary amount of spaces or tabs
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- First token must match `[a-z][a-z0-9_]*`
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- Remaining tokens can be unquoted or quoted tokens.
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- Unquoted tokens consist of all printable characters except double quotes,
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single quotes, spaces and tabs.
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- Quoted tokens are surrounded by a matching pair of double quotes.
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- The closing quote must be followed by space, tab or end of line.
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- Any value is allowed inside a quoted token. Including double quotes,
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assuming it is correctly escaped.
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- Backslash inside a quoted token is used to escape the following
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character.
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For examples see the tests for this function.
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"""
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if not line.strip():
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raise exceptions.MpdNoCommand('No command given')
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match = WORD_RE.match(line)
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if not match:
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raise exceptions.MpdUnknownError('Invalid word character')
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whitespace, command, remainder = match.groups()
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if whitespace:
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raise exceptions.MpdUnknownError('Letter expected')
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result = [command]
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while remainder:
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match = PARAM_RE.match(remainder)
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if not match:
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msg = _determine_error_message(remainder)
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raise exceptions.MpdArgError(msg, command=command)
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unquoted, quoted, remainder = match.groups()
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result.append(unquoted or UNESCAPE_RE.sub(r'\g<1>', quoted))
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return result
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def _determine_error_message(remainder):
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"""Helper to emulate MPD errors."""
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# Following checks are simply to match MPD error messages:
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match = BAD_QUOTED_PARAM_RE.match(remainder)
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if match:
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if match.group(1):
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return 'Space expected after closing \'"\''
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else:
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return 'Missing closing \'"\''
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return 'Invalid unquoted character'
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