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Diffstat (limited to 'src/poezio_shlex.py')
| -rw-r--r-- | src/poezio_shlex.py | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/src/poezio_shlex.py b/src/poezio_shlex.py new file mode 100644 index 00000000..5b3c556c --- /dev/null +++ b/src/poezio_shlex.py @@ -0,0 +1,289 @@ +""" +A lexical analyzer class for simple shell-like syntaxes. + +Tweaked for the specific needs of parsing poezio input. + +""" + +# Module and documentation by Eric S. Raymond, 21 Dec 1998 +# Input stacking and error message cleanup added by ESR, March 2000 +# push_source() and pop_source() made explicit by ESR, January 2001. +# Posix compliance, split(), string arguments, and +# iterator interface by Gustavo Niemeyer, April 2003. + +import os +import re +import sys +from collections import deque + +from io import StringIO + +__all__ = ["shlex", "split", "quote"] + +class shlex: + """ + A custom version of the shlex in the stdlib to yield more information + """ + def __init__(self, instream=None, infile=None, posix=True): + if isinstance(instream, str): + instream = StringIO(instream) + if instream is not None: + self.instream = instream + self.infile = infile + else: + self.instream = sys.stdin + self.infile = None + self.posix = posix + self.eof = '' + self.commenters = '' + self.wordchars = ('abcdfeghijklmnopqrstuvwxyz' + 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_') + if self.posix: + self.wordchars += ('ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ' + 'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ') + self.whitespace = ' \t\r\n' + self.whitespace_split = True + self.quotes = '"' + self.escape = '\\' + self.escapedquotes = '"' + self.state = ' ' + self.pushback = deque() + self.lineno = 1 + self.debug = 0 + self.token = '' + self.filestack = deque() + self.source = None + if self.debug: + print('shlex: reading from %s, line %d' \ + % (self.instream, self.lineno)) + + def push_token(self, tok): + "Push a token onto the stack popped by the get_token method" + if self.debug >= 1: + print("shlex: pushing token " + repr(tok)) + self.pushback.appendleft(tok) + + def push_source(self, newstream, newfile=None): + "Push an input source onto the lexer's input source stack." + if isinstance(newstream, str): + newstream = StringIO(newstream) + self.filestack.appendleft((self.infile, self.instream, self.lineno)) + self.infile = newfile + self.instream = newstream + self.lineno = 1 + if self.debug: + if newfile is not None: + print('shlex: pushing to file %s' % (self.infile,)) + else: + print('shlex: pushing to stream %s' % (self.instream,)) + + def pop_source(self): + "Pop the input source stack." + self.instream.close() + (self.infile, self.instream, self.lineno) = self.filestack.popleft() + if self.debug: + print('shlex: popping to %s, line %d' \ + % (self.instream, self.lineno)) + self.state = ' ' + + def get_token(self): + "Get a token from the input stream (or from stack if it's nonempty)" + if self.pushback: + tok = self.pushback.popleft() + if self.debug >= 1: + print("shlex: popping token " + repr(tok)) + return tok + # No pushback. Get a token. + start, end, raw = self.read_token() + return start, end, raw + + def read_token(self): + quoted = False + escapedstate = ' ' + token_start = 0 + token_end = -1 + while True: + nextchar = self.instream.read(1) + if nextchar == '\n': + self.lineno = self.lineno + 1 + if self.debug >= 3: + print("shlex: in state", repr(self.state), \ + "I see character:", repr(nextchar)) + if self.state is None: + self.token = '' # past end of file + token_end = self.instream.tell() + break + elif self.state == ' ': + if not nextchar: + self.state = None # end of file + token_end = self.instream.tell() + break + elif nextchar in self.whitespace: + if self.debug >= 2: + print("shlex: I see whitespace in whitespace state") + if self.token or (self.posix and quoted): + token_end = self.instream.tell() - 1 + break # emit current token + else: + continue + elif nextchar in self.commenters: + self.instream.readline() + self.lineno = self.lineno + 1 + elif self.posix and nextchar in self.escape: + token_start = self.instream.tell() - 1 + escapedstate = 'a' + self.state = nextchar + elif nextchar in self.wordchars: + token_start = self.instream.tell() - 1 + self.token = nextchar + self.state = 'a' + elif nextchar in self.quotes: + token_start = self.instream.tell() - 1 + self.state = nextchar + elif self.whitespace_split: + token_start = self.instream.tell() - 1 + self.token = nextchar + self.state = 'a' + else: + token_start = self.instream.tell() - 1 + self.token = nextchar + if self.token or (self.posix and quoted): + token_end = self.instream.tell() - 1 + break # emit current token + else: + continue + elif self.state in self.quotes: + quoted = True + if not nextchar: # end of file + if self.debug >= 2: + print("shlex: I see EOF in quotes state") + # XXX what error should be raised here? + token_end = self.instream.tell() + break + if nextchar == self.state: + if not self.posix: + self.token = self.token + nextchar + self.state = ' ' + token_end = self.instream.tell() + break + else: + self.state = 'a' + elif self.posix and nextchar in self.escape and \ + self.state in self.escapedquotes: + escapedstate = self.state + self.state = nextchar + else: + self.token = self.token + nextchar + elif self.state in self.escape: + if not nextchar: # end of file + if self.debug >= 2: + print("shlex: I see EOF in escape state") + # XXX what error should be raised here? + token_end = self.instream.tell() + break + # In posix shells, only the quote itself or the escape + # character may be escaped within quotes. + if escapedstate in self.quotes and \ + nextchar != self.state and nextchar != escapedstate: + self.token = self.token + self.state + self.token = self.token + nextchar + self.state = escapedstate + elif self.state == 'a': + if not nextchar: + self.state = None # end of file + token_end = self.instream.tell() + break + elif nextchar in self.whitespace: + if self.debug >= 2: + print("shlex: I see whitespace in word state") + self.state = ' ' + if self.token or (self.posix and quoted): + token_end = self.instream.tell() - 1 + break # emit current token + else: + continue + elif self.posix and nextchar in self.quotes: + self.state = nextchar + elif self.posix and nextchar in self.escape: + escapedstate = 'a' + self.state = nextchar + elif nextchar in self.wordchars or nextchar in self.quotes \ + or self.whitespace_split: + self.token = self.token + nextchar + else: + self.pushback.appendleft(nextchar) + if self.debug >= 2: + print("shlex: I see punctuation in word state") + self.state = ' ' + if self.token: + token_end = self.instream.tell() + break # emit current token + else: + continue + result = self.token + self.token = '' + if self.posix and not quoted and result == '': + result = None + if self.debug > 1: + if result: + print("shlex: raw token=" + repr(result)) + else: + print("shlex: raw token=EOF") + return (token_start, token_end, result) + + def sourcehook(self, newfile): + "Hook called on a filename to be sourced." + if newfile[0] == '"': + newfile = newfile[1:-1] + # This implements cpp-like semantics for relative-path inclusion. + if isinstance(self.infile, str) and not os.path.isabs(newfile): + newfile = os.path.join(os.path.dirname(self.infile), newfile) + return (newfile, open(newfile, "r")) + + def error_leader(self, infile=None, lineno=None): + "Emit a C-compiler-like, Emacs-friendly error-message leader." + if infile is None: + infile = self.infile + if lineno is None: + lineno = self.lineno + return "\"%s\", line %d: " % (infile, lineno) + + def __iter__(self): + return self + + def __next__(self): + token = self.get_token() + if token and token[0] == self.eof: + raise StopIteration + return token + +def split(s, comments=False, posix=True): + lex = shlex(s, posix=posix) + lex.whitespace_split = True + if not comments: + lex.commenters = '' + return list(lex) + + +_find_unsafe = re.compile(r'[^\w@%+=:,./-]', re.ASCII).search + +def quote(s): + """Return a shell-escaped version of the string *s*.""" + if not s: + return "''" + if _find_unsafe(s) is None: + return s + + # use single quotes, and put single quotes into double quotes + # the string $'b is then quoted as '$'"'"'b' + return "'" + s.replace("'", "'\"'\"'") + "'" + + +if __name__ == '__main__': + lexer = shlex(instream=sys.argv[1]) + while 1: + tt = lexer.get_token() + if tt: + print("Token: " + repr(tt)) + else: + break |