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349 lines
13 KiB
349 lines
13 KiB
"""A lexical analyzer class for simple shell-like syntaxes.""" |
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# Module and documentation by Eric S. Raymond, 21 Dec 1998 |
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# Input stacking and error message cleanup added by ESR, March 2000 |
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# push_source() and pop_source() made explicit by ESR, January 2001. |
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# Posix compliance, split(), string arguments, and |
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# iterator interface by Gustavo Niemeyer, April 2003. |
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# changes to tokenize more like Posix shells by Vinay Sajip, July 2016. |
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import os |
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import re |
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import sys |
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from io import StringIO |
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__all__ = ["shlex", "split", "quote", "join"] |
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class shlex: |
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"A lexical analyzer class for simple shell-like syntaxes." |
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def __init__(self, instream=None, infile=None, posix=False, |
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punctuation_chars=False): |
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if isinstance(instream, str): |
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instream = StringIO(instream) |
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if instream is not None: |
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self.instream = instream |
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self.infile = infile |
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else: |
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self.instream = sys.stdin |
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self.infile = None |
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self.posix = posix |
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if posix: |
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self.eof = None |
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else: |
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self.eof = '' |
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self.commenters = '#' |
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self.wordchars = ('abcdfeghijklmnopqrstuvwxyz' |
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'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_') |
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if self.posix: |
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self.wordchars += ('ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ' |
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'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ') |
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self.whitespace = ' \t\r\n' |
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self.whitespace_split = False |
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self.quotes = '\'"' |
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self.escape = '\\' |
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self.escapedquotes = '"' |
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self.state = ' ' |
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self.pushback = list() |
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self.lineno = 1 |
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self.debug = 0 |
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self.token = '' |
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self.filestack = list() |
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self.source = None |
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if not punctuation_chars: |
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punctuation_chars = '' |
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elif punctuation_chars is True: |
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punctuation_chars = '();<>|&' |
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self._punctuation_chars = punctuation_chars |
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if punctuation_chars: |
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# _pushback_chars is a push back queue used by lookahead logic |
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self._pushback_chars = list() |
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# these chars added because allowed in file names, args, wildcards |
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self.wordchars += '~-./*?=' |
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#remove any punctuation chars from wordchars |
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t = self.wordchars.maketrans(dict.fromkeys(punctuation_chars)) |
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self.wordchars = self.wordchars.translate(t) |
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@property |
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def punctuation_chars(self): |
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return self._punctuation_chars |
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def push_token(self, tok): |
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"Push a token onto the stack popped by the get_token method" |
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if self.debug >= 1: |
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print("shlex: pushing token " + repr(tok)) |
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self.pushback.appendleft(tok) |
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def push_source(self, newstream, newfile=None): |
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"Push an input source onto the lexer's input source stack." |
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if isinstance(newstream, str): |
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newstream = StringIO(newstream) |
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self.filestack.appendleft((self.infile, self.instream, self.lineno)) |
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self.infile = newfile |
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self.instream = newstream |
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self.lineno = 1 |
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if self.debug: |
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if newfile is not None: |
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print('shlex: pushing to file %s' % (self.infile,)) |
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else: |
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print('shlex: pushing to stream %s' % (self.instream,)) |
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def pop_source(self): |
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"Pop the input source stack." |
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self.instream.close() |
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(self.infile, self.instream, self.lineno) = self.filestack.popleft() |
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if self.debug: |
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print('shlex: popping to %s, line %d' \ |
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% (self.instream, self.lineno)) |
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self.state = ' ' |
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def get_token(self): |
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"Get a token from the input stream (or from stack if it's nonempty)" |
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if self.pushback: |
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tok = self.pushback.popleft() |
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if self.debug >= 1: |
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print("shlex: popping token " + repr(tok)) |
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return tok |
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# No pushback. Get a token. |
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raw = self.read_token() |
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# Handle inclusions |
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if self.source is not None: |
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while raw == self.source: |
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spec = self.sourcehook(self.read_token()) |
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if spec: |
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(newfile, newstream) = spec |
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self.push_source(newstream, newfile) |
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raw = self.get_token() |
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# Maybe we got EOF instead? |
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while raw == self.eof: |
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if not self.filestack: |
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return self.eof |
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else: |
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self.pop_source() |
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raw = self.get_token() |
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# Neither inclusion nor EOF |
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if self.debug >= 1: |
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if raw != self.eof: |
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print("shlex: token=" + repr(raw)) |
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else: |
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print("shlex: token=EOF") |
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return raw |
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def read_token(self): |
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quoted = False |
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escapedstate = ' ' |
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while True: |
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if self.punctuation_chars and self._pushback_chars: |
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nextchar = self._pushback_chars.pop() |
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else: |
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nextchar = self.instream.read(1) |
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if nextchar == '\n': |
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self.lineno += 1 |
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if self.debug >= 3: |
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print("shlex: in state %r I see character: %r" % (self.state, |
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nextchar)) |
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if self.state is None: |
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self.token = '' # past end of file |
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break |
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elif self.state == ' ': |
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if not nextchar: |
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self.state = None # end of file |
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break |
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elif nextchar in self.whitespace: |
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if self.debug >= 2: |
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print("shlex: I see whitespace in whitespace state") |
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if self.token or (self.posix and quoted): |
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break # emit current token |
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else: |
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continue |
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elif nextchar in self.commenters: |
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self.instream.readline() |
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self.lineno += 1 |
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elif self.posix and nextchar in self.escape: |
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escapedstate = 'a' |
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self.state = nextchar |
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elif nextchar in self.wordchars: |
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self.token = nextchar |
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self.state = 'a' |
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elif nextchar in self.punctuation_chars: |
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self.token = nextchar |
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self.state = 'c' |
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elif nextchar in self.quotes: |
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if not self.posix: |
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self.token = nextchar |
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self.state = nextchar |
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elif self.whitespace_split: |
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self.token = nextchar |
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self.state = 'a' |
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else: |
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self.token = nextchar |
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if self.token or (self.posix and quoted): |
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break # emit current token |
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else: |
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continue |
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elif self.state in self.quotes: |
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quoted = True |
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if not nextchar: # end of file |
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if self.debug >= 2: |
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print("shlex: I see EOF in quotes state") |
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# XXX what error should be raised here? |
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raise ValueError("No closing quotation") |
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if nextchar == self.state: |
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if not self.posix: |
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self.token += nextchar |
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self.state = ' ' |
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break |
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else: |
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self.state = 'a' |
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elif (self.posix and nextchar in self.escape and self.state |
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in self.escapedquotes): |
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escapedstate = self.state |
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self.state = nextchar |
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else: |
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self.token += nextchar |
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elif self.state in self.escape: |
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if not nextchar: # end of file |
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if self.debug >= 2: |
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print("shlex: I see EOF in escape state") |
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# XXX what error should be raised here? |
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raise ValueError("No escaped character") |
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# In posix shells, only the quote itself or the escape |
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# character may be escaped within quotes. |
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if (escapedstate in self.quotes and |
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nextchar != self.state and nextchar != escapedstate): |
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self.token += self.state |
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self.token += nextchar |
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self.state = escapedstate |
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elif self.state in ('a', 'c'): |
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if not nextchar: |
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self.state = None # end of file |
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break |
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elif nextchar in self.whitespace: |
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if self.debug >= 2: |
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print("shlex: I see whitespace in word state") |
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self.state = ' ' |
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if self.token or (self.posix and quoted): |
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break # emit current token |
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else: |
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continue |
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elif nextchar in self.commenters: |
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self.instream.readline() |
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self.lineno += 1 |
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if self.posix: |
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self.state = ' ' |
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if self.token or (self.posix and quoted): |
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break # emit current token |
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else: |
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continue |
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elif self.state == 'c': |
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if nextchar in self.punctuation_chars: |
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self.token += nextchar |
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else: |
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if nextchar not in self.whitespace: |
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self._pushback_chars.append(nextchar) |
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self.state = ' ' |
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break |
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elif self.posix and nextchar in self.quotes: |
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self.state = nextchar |
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elif self.posix and nextchar in self.escape: |
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escapedstate = 'a' |
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self.state = nextchar |
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elif (nextchar in self.wordchars or nextchar in self.quotes |
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or (self.whitespace_split and |
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nextchar not in self.punctuation_chars)): |
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self.token += nextchar |
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else: |
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if self.punctuation_chars: |
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self._pushback_chars.append(nextchar) |
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else: |
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self.pushback.appendleft(nextchar) |
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if self.debug >= 2: |
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print("shlex: I see punctuation in word state") |
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self.state = ' ' |
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if self.token or (self.posix and quoted): |
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break # emit current token |
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else: |
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continue |
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result = self.token |
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self.token = '' |
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if self.posix and not quoted and result == '': |
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result = None |
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if self.debug > 1: |
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if result: |
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print("shlex: raw token=" + repr(result)) |
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else: |
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print("shlex: raw token=EOF") |
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return result |
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def sourcehook(self, newfile): |
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"Hook called on a filename to be sourced." |
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if newfile[0] == '"': |
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newfile = newfile[1:-1] |
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# This implements cpp-like semantics for relative-path inclusion. |
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if isinstance(self.infile, str) and not os.path.isabs(newfile): |
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newfile = os.path.join(os.path.dirname(self.infile), newfile) |
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return (newfile, open(newfile, "r")) |
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def error_leader(self, infile=None, lineno=None): |
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"Emit a C-compiler-like, Emacs-friendly error-message leader." |
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if infile is None: |
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infile = self.infile |
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if lineno is None: |
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lineno = self.lineno |
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return "\"%s\", line %d: " % (infile, lineno) |
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def __iter__(self): |
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return self |
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def __next__(self): |
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token = self.get_token() |
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if token == self.eof: |
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raise StopIteration |
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return token |
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def split(s, comments=False, posix=True): |
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"""Split the string *s* using shell-like syntax.""" |
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if s is None: |
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import warnings |
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warnings.warn("Passing None for 's' to shlex.split() is deprecated.", |
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DeprecationWarning, stacklevel=2) |
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lex = shlex(s, posix=posix) |
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lex.whitespace_split = True |
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if not comments: |
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lex.commenters = '' |
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return list(lex) |
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def join(split_command): |
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"""Return a shell-escaped string from *split_command*.""" |
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return ' '.join(quote(arg) for arg in split_command) |
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_find_unsafe = re.compile(r'[^\w@%+=:,./-]').search #, re.ASCII).search |
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def quote(s): |
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"""Return a shell-escaped version of the string *s*.""" |
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if not s: |
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return "''" |
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if _find_unsafe(s) is None: |
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return s |
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# use single quotes, and put single quotes into double quotes |
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# the string $'b is then quoted as '$'"'"'b' |
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return "'" + s.replace("'", "'\"'\"'") + "'" |
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def _print_tokens(lexer): |
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while 1: |
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tt = lexer.get_token() |
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if not tt: |
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break |
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print("Token: " + repr(tt)) |
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if __name__ == '__main__': |
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if len(sys.argv) == 1: |
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_print_tokens(shlex()) |
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else: |
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fn = sys.argv[1] |
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with open(fn) as f: |
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_print_tokens(shlex(f, fn))
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