1"""A lexical analyzer class for simple shell-like syntaxes."""
2
3# Module and documentation by Eric S. Raymond, 21 Dec 1998
4# Input stacking and error message cleanup added by ESR, March 2000
5# push_source() and pop_source() made explicit by ESR, January 2001.
6# Posix compliance, split(), string arguments, and
7# iterator interface by Gustavo Niemeyer, April 2003.
8# changes to tokenize more like Posix shells by Vinay Sajip, July 2016.
9
10import os
11import re
12import sys
13from collections import deque
14
15from io import StringIO
16
17__all__ = ["shlex", "split", "quote"]
18
19class shlex:
20    "A lexical analyzer class for simple shell-like syntaxes."
21    def __init__(self, instream=None, infile=None, posix=False,
22                 punctuation_chars=False):
23        if isinstance(instream, str):
24            instream = StringIO(instream)
25        if instream is not None:
26            self.instream = instream
27            self.infile = infile
28        else:
29            self.instream = sys.stdin
30            self.infile = None
31        self.posix = posix
32        if posix:
33            self.eof = None
34        else:
35            self.eof = ''
36        self.commenters = '#'
37        self.wordchars = ('abcdfeghijklmnopqrstuvwxyz'
38                          'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_')
39        if self.posix:
40            self.wordchars += ('ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ'
41                               'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ')
42        self.whitespace = ' \t\r\n'
43        self.whitespace_split = False
44        self.quotes = '\'"'
45        self.escape = '\\'
46        self.escapedquotes = '"'
47        self.state = ' '
48        self.pushback = deque()
49        self.lineno = 1
50        self.debug = 0
51        self.token = ''
52        self.filestack = deque()
53        self.source = None
54        if not punctuation_chars:
55            punctuation_chars = ''
56        elif punctuation_chars is True:
57            punctuation_chars = '();<>|&'
58        self.punctuation_chars = punctuation_chars
59        if punctuation_chars:
60            # _pushback_chars is a push back queue used by lookahead logic
61            self._pushback_chars = deque()
62            # these chars added because allowed in file names, args, wildcards
63            self.wordchars += '~-./*?='
64            #remove any punctuation chars from wordchars
65            t = self.wordchars.maketrans(dict.fromkeys(punctuation_chars))
66            self.wordchars = self.wordchars.translate(t)
67
68    def push_token(self, tok):
69        "Push a token onto the stack popped by the get_token method"
70        if self.debug >= 1:
71            print("shlex: pushing token " + repr(tok))
72        self.pushback.appendleft(tok)
73
74    def push_source(self, newstream, newfile=None):
75        "Push an input source onto the lexer's input source stack."
76        if isinstance(newstream, str):
77            newstream = StringIO(newstream)
78        self.filestack.appendleft((self.infile, self.instream, self.lineno))
79        self.infile = newfile
80        self.instream = newstream
81        self.lineno = 1
82        if self.debug:
83            if newfile is not None:
84                print('shlex: pushing to file %s' % (self.infile,))
85            else:
86                print('shlex: pushing to stream %s' % (self.instream,))
87
88    def pop_source(self):
89        "Pop the input source stack."
90        self.instream.close()
91        (self.infile, self.instream, self.lineno) = self.filestack.popleft()
92        if self.debug:
93            print('shlex: popping to %s, line %d' \
94                  % (self.instream, self.lineno))
95        self.state = ' '
96
97    def get_token(self):
98        "Get a token from the input stream (or from stack if it's nonempty)"
99        if self.pushback:
100            tok = self.pushback.popleft()
101            if self.debug >= 1:
102                print("shlex: popping token " + repr(tok))
103            return tok
104        # No pushback.  Get a token.
105        raw = self.read_token()
106        # Handle inclusions
107        if self.source is not None:
108            while raw == self.source:
109                spec = self.sourcehook(self.read_token())
110                if spec:
111                    (newfile, newstream) = spec
112                    self.push_source(newstream, newfile)
113                raw = self.get_token()
114        # Maybe we got EOF instead?
115        while raw == self.eof:
116            if not self.filestack:
117                return self.eof
118            else:
119                self.pop_source()
120                raw = self.get_token()
121        # Neither inclusion nor EOF
122        if self.debug >= 1:
123            if raw != self.eof:
124                print("shlex: token=" + repr(raw))
125            else:
126                print("shlex: token=EOF")
127        return raw
128
129    def read_token(self):
130        quoted = False
131        escapedstate = ' '
132        while True:
133            if self.punctuation_chars and self._pushback_chars:
134                nextchar = self._pushback_chars.pop()
135            else:
136                nextchar = self.instream.read(1)
137            if nextchar == '\n':
138                self.lineno += 1
139            if self.debug >= 3:
140                print("shlex: in state %r I see character: %r" % (self.state,
141                                                                  nextchar))
142            if self.state is None:
143                self.token = ''        # past end of file
144                break
145            elif self.state == ' ':
146                if not nextchar:
147                    self.state = None  # end of file
148                    break
149                elif nextchar in self.whitespace:
150                    if self.debug >= 2:
151                        print("shlex: I see whitespace in whitespace state")
152                    if self.token or (self.posix and quoted):
153                        break   # emit current token
154                    else:
155                        continue
156                elif nextchar in self.commenters:
157                    self.instream.readline()
158                    self.lineno += 1
159                elif self.posix and nextchar in self.escape:
160                    escapedstate = 'a'
161                    self.state = nextchar
162                elif nextchar in self.wordchars:
163                    self.token = nextchar
164                    self.state = 'a'
165                elif nextchar in self.punctuation_chars:
166                    self.token = nextchar
167                    self.state = 'c'
168                elif nextchar in self.quotes:
169                    if not self.posix:
170                        self.token = nextchar
171                    self.state = nextchar
172                elif self.whitespace_split:
173                    self.token = nextchar
174                    self.state = 'a'
175                else:
176                    self.token = nextchar
177                    if self.token or (self.posix and quoted):
178                        break   # emit current token
179                    else:
180                        continue
181            elif self.state in self.quotes:
182                quoted = True
183                if not nextchar:      # end of file
184                    if self.debug >= 2:
185                        print("shlex: I see EOF in quotes state")
186                    # XXX what error should be raised here?
187                    raise ValueError("No closing quotation")
188                if nextchar == self.state:
189                    if not self.posix:
190                        self.token += nextchar
191                        self.state = ' '
192                        break
193                    else:
194                        self.state = 'a'
195                elif (self.posix and nextchar in self.escape and self.state
196                      in self.escapedquotes):
197                    escapedstate = self.state
198                    self.state = nextchar
199                else:
200                    self.token += nextchar
201            elif self.state in self.escape:
202                if not nextchar:      # end of file
203                    if self.debug >= 2:
204                        print("shlex: I see EOF in escape state")
205                    # XXX what error should be raised here?
206                    raise ValueError("No escaped character")
207                # In posix shells, only the quote itself or the escape
208                # character may be escaped within quotes.
209                if (escapedstate in self.quotes and
210                        nextchar != self.state and nextchar != escapedstate):
211                    self.token += self.state
212                self.token += nextchar
213                self.state = escapedstate
214            elif self.state in ('a', 'c'):
215                if not nextchar:
216                    self.state = None   # end of file
217                    break
218                elif nextchar in self.whitespace:
219                    if self.debug >= 2:
220                        print("shlex: I see whitespace in word state")
221                    self.state = ' '
222                    if self.token or (self.posix and quoted):
223                        break   # emit current token
224                    else:
225                        continue
226                elif nextchar in self.commenters:
227                    self.instream.readline()
228                    self.lineno += 1
229                    if self.posix:
230                        self.state = ' '
231                        if self.token or (self.posix and quoted):
232                            break   # emit current token
233                        else:
234                            continue
235                elif self.state == 'c':
236                    if nextchar in self.punctuation_chars:
237                        self.token += nextchar
238                    else:
239                        if nextchar not in self.whitespace:
240                            self._pushback_chars.append(nextchar)
241                        self.state = ' '
242                        break
243                elif self.posix and nextchar in self.quotes:
244                    self.state = nextchar
245                elif self.posix and nextchar in self.escape:
246                    escapedstate = 'a'
247                    self.state = nextchar
248                elif (nextchar in self.wordchars or nextchar in self.quotes
249                      or self.whitespace_split):
250                    self.token += nextchar
251                else:
252                    if self.punctuation_chars:
253                        self._pushback_chars.append(nextchar)
254                    else:
255                        self.pushback.appendleft(nextchar)
256                    if self.debug >= 2:
257                        print("shlex: I see punctuation in word state")
258                    self.state = ' '
259                    if self.token or (self.posix and quoted):
260                        break   # emit current token
261                    else:
262                        continue
263        result = self.token
264        self.token = ''
265        if self.posix and not quoted and result == '':
266            result = None
267        if self.debug > 1:
268            if result:
269                print("shlex: raw token=" + repr(result))
270            else:
271                print("shlex: raw token=EOF")
272        return result
273
274    def sourcehook(self, newfile):
275        "Hook called on a filename to be sourced."
276        if newfile[0] == '"':
277            newfile = newfile[1:-1]
278        # This implements cpp-like semantics for relative-path inclusion.
279        if isinstance(self.infile, str) and not os.path.isabs(newfile):
280            newfile = os.path.join(os.path.dirname(self.infile), newfile)
281        return (newfile, open(newfile, "r"))
282
283    def error_leader(self, infile=None, lineno=None):
284        "Emit a C-compiler-like, Emacs-friendly error-message leader."
285        if infile is None:
286            infile = self.infile
287        if lineno is None:
288            lineno = self.lineno
289        return "\"%s\", line %d: " % (infile, lineno)
290
291    def __iter__(self):
292        return self
293
294    def __next__(self):
295        token = self.get_token()
296        if token == self.eof:
297            raise StopIteration
298        return token
299
300def split(s, comments=False, posix=True):
301    lex = shlex(s, posix=posix)
302    lex.whitespace_split = True
303    if not comments:
304        lex.commenters = ''
305    return list(lex)
306
307
308_find_unsafe = re.compile(r'[^\w@%+=:,./-]', re.ASCII).search
309
310def quote(s):
311    """Return a shell-escaped version of the string *s*."""
312    if not s:
313        return "''"
314    if _find_unsafe(s) is None:
315        return s
316
317    # use single quotes, and put single quotes into double quotes
318    # the string $'b is then quoted as '$'"'"'b'
319    return "'" + s.replace("'", "'\"'\"'") + "'"
320
321
322def _print_tokens(lexer):
323    while 1:
324        tt = lexer.get_token()
325        if not tt:
326            break
327        print("Token: " + repr(tt))
328
329if __name__ == '__main__':
330    if len(sys.argv) == 1:
331        _print_tokens(shlex())
332    else:
333        fn = sys.argv[1]
334        with open(fn) as f:
335            _print_tokens(shlex(f, fn))
336