forked from OSchip/llvm-project
347 lines
11 KiB
Python
347 lines
11 KiB
Python
import itertools
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import Util
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from ShCommands import Command, Pipeline, Seq
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class ShLexer:
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def __init__(self, data, win32Escapes = False):
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self.data = data
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self.pos = 0
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self.end = len(data)
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self.win32Escapes = win32Escapes
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def eat(self):
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c = self.data[self.pos]
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self.pos += 1
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return c
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def look(self):
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return self.data[self.pos]
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def maybe_eat(self, c):
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"""
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maybe_eat(c) - Consume the character c if it is the next character,
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returning True if a character was consumed. """
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if self.data[self.pos] == c:
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self.pos += 1
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return True
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return False
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def lex_arg_fast(self, c):
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# Get the leading whitespace free section.
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chunk = self.data[self.pos - 1:].split(None, 1)[0]
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# If it has special characters, the fast path failed.
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if ('|' in chunk or '&' in chunk or
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'<' in chunk or '>' in chunk or
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"'" in chunk or '"' in chunk or
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'\\' in chunk):
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return None
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self.pos = self.pos - 1 + len(chunk)
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return chunk
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def lex_arg_slow(self, c):
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if c in "'\"":
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str = self.lex_arg_quoted(c)
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else:
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str = c
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while self.pos != self.end:
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c = self.look()
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if c.isspace() or c in "|&":
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break
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elif c in '><':
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# This is an annoying case; we treat '2>' as a single token so
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# we don't have to track whitespace tokens.
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# If the parse string isn't an integer, do the usual thing.
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if not str.isdigit():
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break
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# Otherwise, lex the operator and convert to a redirection
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# token.
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num = int(str)
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tok = self.lex_one_token()
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assert isinstance(tok, tuple) and len(tok) == 1
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return (tok[0], num)
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elif c == '"':
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self.eat()
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str += self.lex_arg_quoted('"')
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elif not self.win32Escapes and c == '\\':
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# Outside of a string, '\\' escapes everything.
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self.eat()
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if self.pos == self.end:
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Util.warning("escape at end of quoted argument in: %r" %
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self.data)
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return str
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str += self.eat()
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else:
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str += self.eat()
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return str
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def lex_arg_quoted(self, delim):
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str = ''
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while self.pos != self.end:
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c = self.eat()
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if c == delim:
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return str
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elif c == '\\' and delim == '"':
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# Inside a '"' quoted string, '\\' only escapes the quote
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# character and backslash, otherwise it is preserved.
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if self.pos == self.end:
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Util.warning("escape at end of quoted argument in: %r" %
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self.data)
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return str
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c = self.eat()
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if c == '"': #
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str += '"'
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elif c == '\\':
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str += '\\'
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else:
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str += '\\' + c
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else:
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str += c
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Util.warning("missing quote character in %r" % self.data)
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return str
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def lex_arg_checked(self, c):
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pos = self.pos
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res = self.lex_arg_fast(c)
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end = self.pos
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self.pos = pos
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reference = self.lex_arg_slow(c)
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if res is not None:
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if res != reference:
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raise ValueError,"Fast path failure: %r != %r" % (res, reference)
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if self.pos != end:
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raise ValueError,"Fast path failure: %r != %r" % (self.pos, end)
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return reference
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def lex_arg(self, c):
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return self.lex_arg_fast(c) or self.lex_arg_slow(c)
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def lex_one_token(self):
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"""
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lex_one_token - Lex a single 'sh' token. """
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c = self.eat()
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if c in ';!':
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return (c,)
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if c == '|':
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if self.maybe_eat('|'):
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return ('||',)
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return (c,)
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if c == '&':
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if self.maybe_eat('&'):
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return ('&&',)
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if self.maybe_eat('>'):
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return ('&>',)
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return (c,)
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if c == '>':
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if self.maybe_eat('&'):
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return ('>&',)
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if self.maybe_eat('>'):
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return ('>>',)
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return (c,)
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if c == '<':
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if self.maybe_eat('&'):
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return ('<&',)
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if self.maybe_eat('>'):
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return ('<<',)
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return (c,)
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return self.lex_arg(c)
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def lex(self):
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while self.pos != self.end:
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if self.look().isspace():
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self.eat()
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else:
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yield self.lex_one_token()
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###
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class ShParser:
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def __init__(self, data, win32Escapes = False):
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self.data = data
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self.tokens = ShLexer(data, win32Escapes = win32Escapes).lex()
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def lex(self):
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try:
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return self.tokens.next()
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except StopIteration:
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return None
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def look(self):
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next = self.lex()
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if next is not None:
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self.tokens = itertools.chain([next], self.tokens)
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return next
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def parse_command(self):
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tok = self.lex()
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if not tok:
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raise ValueError,"empty command!"
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if isinstance(tok, tuple):
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raise ValueError,"syntax error near unexpected token %r" % tok[0]
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args = [tok]
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redirects = []
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while 1:
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tok = self.look()
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# EOF?
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if tok is None:
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break
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# If this is an argument, just add it to the current command.
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if isinstance(tok, str):
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args.append(self.lex())
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continue
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# Otherwise see if it is a terminator.
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assert isinstance(tok, tuple)
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if tok[0] in ('|',';','&','||','&&'):
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break
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# Otherwise it must be a redirection.
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op = self.lex()
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arg = self.lex()
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if not arg:
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raise ValueError,"syntax error near token %r" % op[0]
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redirects.append((op, arg))
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return Command(args, redirects)
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def parse_pipeline(self):
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negate = False
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if self.look() == ('!',):
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self.lex()
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negate = True
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commands = [self.parse_command()]
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while self.look() == ('|',):
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self.lex()
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commands.append(self.parse_command())
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return Pipeline(commands, negate)
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def parse(self):
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lhs = self.parse_pipeline()
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while self.look():
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operator = self.lex()
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assert isinstance(operator, tuple) and len(operator) == 1
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if not self.look():
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raise ValueError, "missing argument to operator %r" % operator[0]
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# FIXME: Operator precedence!!
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lhs = Seq(lhs, operator[0], self.parse_pipeline())
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return lhs
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###
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import unittest
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class TestShLexer(unittest.TestCase):
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def lex(self, str, *args, **kwargs):
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return list(ShLexer(str, *args, **kwargs).lex())
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def test_basic(self):
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self.assertEqual(self.lex('a|b>c&d<e'),
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['a', ('|',), 'b', ('>',), 'c', ('&',), 'd',
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('<',), 'e'])
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def test_redirection_tokens(self):
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self.assertEqual(self.lex('a2>c'),
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['a2', ('>',), 'c'])
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self.assertEqual(self.lex('a 2>c'),
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['a', ('>',2), 'c'])
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def test_quoting(self):
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self.assertEqual(self.lex(""" 'a' """),
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['a'])
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self.assertEqual(self.lex(""" "hello\\"world" """),
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['hello"world'])
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self.assertEqual(self.lex(""" "hello\\'world" """),
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["hello\\'world"])
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self.assertEqual(self.lex(""" "hello\\\\world" """),
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["hello\\world"])
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self.assertEqual(self.lex(""" he"llo wo"rld """),
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["hello world"])
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self.assertEqual(self.lex(""" a\\ b a\\\\b """),
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["a b", "a\\b"])
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self.assertEqual(self.lex(""" "" "" """),
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["", ""])
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self.assertEqual(self.lex(""" a\\ b """, win32Escapes = True),
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['a\\', 'b'])
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class TestShParse(unittest.TestCase):
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def parse(self, str):
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return ShParser(str).parse()
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def test_basic(self):
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self.assertEqual(self.parse('echo hello'),
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Pipeline([Command(['echo', 'hello'], [])], False))
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self.assertEqual(self.parse('echo ""'),
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Pipeline([Command(['echo', ''], [])], False))
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def test_redirection(self):
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self.assertEqual(self.parse('echo hello > c'),
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Pipeline([Command(['echo', 'hello'],
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[((('>'),), 'c')])], False))
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self.assertEqual(self.parse('echo hello > c >> d'),
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Pipeline([Command(['echo', 'hello'], [(('>',), 'c'),
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(('>>',), 'd')])], False))
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self.assertEqual(self.parse('a 2>&1'),
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Pipeline([Command(['a'], [(('>&',2), '1')])], False))
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def test_pipeline(self):
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self.assertEqual(self.parse('a | b'),
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Pipeline([Command(['a'], []),
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Command(['b'], [])],
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False))
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self.assertEqual(self.parse('a | b | c'),
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Pipeline([Command(['a'], []),
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Command(['b'], []),
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Command(['c'], [])],
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False))
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self.assertEqual(self.parse('! a'),
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Pipeline([Command(['a'], [])],
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True))
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def test_list(self):
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self.assertEqual(self.parse('a ; b'),
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Seq(Pipeline([Command(['a'], [])], False),
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';',
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Pipeline([Command(['b'], [])], False)))
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self.assertEqual(self.parse('a & b'),
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Seq(Pipeline([Command(['a'], [])], False),
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'&',
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Pipeline([Command(['b'], [])], False)))
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self.assertEqual(self.parse('a && b'),
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Seq(Pipeline([Command(['a'], [])], False),
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'&&',
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Pipeline([Command(['b'], [])], False)))
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self.assertEqual(self.parse('a || b'),
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Seq(Pipeline([Command(['a'], [])], False),
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'||',
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Pipeline([Command(['b'], [])], False)))
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self.assertEqual(self.parse('a && b || c'),
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Seq(Seq(Pipeline([Command(['a'], [])], False),
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'&&',
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Pipeline([Command(['b'], [])], False)),
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'||',
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Pipeline([Command(['c'], [])], False)))
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if __name__ == '__main__':
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unittest.main()
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