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-rw-r--r--utils/lit/TclUtil.py322
1 files changed, 322 insertions, 0 deletions
diff --git a/utils/lit/TclUtil.py b/utils/lit/TclUtil.py
new file mode 100644
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--- /dev/null
+++ b/utils/lit/TclUtil.py
@@ -0,0 +1,322 @@
+import itertools
+
+from ShCommands import Command, Pipeline
+
+def tcl_preprocess(data):
+ # Tcl has a preprocessing step to replace escaped newlines.
+ i = data.find('\\\n')
+ if i == -1:
+ return data
+
+ # Replace '\\\n' and subsequent whitespace by a single space.
+ n = len(data)
+ str = data[:i]
+ i += 2
+ while i < n and data[i] in ' \t':
+ i += 1
+ return str + ' ' + data[i:]
+
+class TclLexer:
+ """TclLexer - Lex a string into "words", following the Tcl syntax."""
+
+ def __init__(self, data):
+ self.data = tcl_preprocess(data)
+ self.pos = 0
+ self.end = len(self.data)
+
+ def at_end(self):
+ return self.pos == self.end
+
+ def eat(self):
+ c = self.data[self.pos]
+ self.pos += 1
+ return c
+
+ def look(self):
+ return self.data[self.pos]
+
+ def maybe_eat(self, c):
+ """
+ maybe_eat(c) - Consume the character c if it is the next character,
+ returning True if a character was consumed. """
+ if self.data[self.pos] == c:
+ self.pos += 1
+ return True
+ return False
+
+ def escape(self, c):
+ if c == 'a':
+ return '\x07'
+ elif c == 'b':
+ return '\x08'
+ elif c == 'f':
+ return '\x0c'
+ elif c == 'n':
+ return '\n'
+ elif c == 'r':
+ return '\r'
+ elif c == 't':
+ return '\t'
+ elif c == 'v':
+ return '\x0b'
+ elif c in 'uxo':
+ raise ValueError,'Invalid quoted character %r' % c
+ else:
+ return c
+
+ def lex_braced(self):
+ # Lex until whitespace or end of string, the opening brace has already
+ # been consumed.
+
+ str = ''
+ while 1:
+ if self.at_end():
+ raise ValueError,"Unterminated '{' quoted word"
+
+ c = self.eat()
+ if c == '}':
+ break
+ elif c == '{':
+ str += '{' + self.lex_braced() + '}'
+ elif c == '\\' and self.look() in '{}':
+ str += self.eat()
+ else:
+ str += c
+
+ return str
+
+ def lex_quoted(self):
+ str = ''
+
+ while 1:
+ if self.at_end():
+ raise ValueError,"Unterminated '\"' quoted word"
+
+ c = self.eat()
+ if c == '"':
+ break
+ elif c == '\\':
+ if self.at_end():
+ raise ValueError,'Missing quoted character'
+
+ str += self.escape(self.eat())
+ else:
+ str += c
+
+ return str
+
+ def lex_unquoted(self, process_all=False):
+ # Lex until whitespace or end of string.
+ str = ''
+ while not self.at_end():
+ if not process_all:
+ if self.look().isspace() or self.look() == ';':
+ break
+
+ c = self.eat()
+ if c == '\\':
+ if self.at_end():
+ raise ValueError,'Missing quoted character'
+
+ str += self.escape(self.eat())
+ elif c == '[':
+ raise NotImplementedError, ('Command substitution is '
+ 'not supported')
+ elif c == '$' and not self.at_end() and (self.look().isalpha() or
+ self.look() == '{'):
+ raise NotImplementedError, ('Variable substitution is '
+ 'not supported')
+ else:
+ str += c
+
+ return str
+
+ def lex_one_token(self):
+ if self.maybe_eat('"'):
+ return self.lex_quoted()
+ elif self.maybe_eat('{'):
+ # Check for argument substitution.
+ if not self.maybe_eat('*'):
+ return self.lex_braced()
+
+ if not self.maybe_eat('}'):
+ return '*' + self.lex_braced()
+
+ if self.at_end() or self.look().isspace():
+ return '*'
+
+ raise NotImplementedError, "Argument substitution is unsupported"
+ else:
+ return self.lex_unquoted()
+
+ def lex(self):
+ while not self.at_end():
+ c = self.look()
+ if c in ' \t':
+ self.eat()
+ elif c in ';\n':
+ self.eat()
+ yield (';',)
+ else:
+ yield self.lex_one_token()
+
+class TclExecCommand:
+ kRedirectPrefixes1 = ('<', '>')
+ kRedirectPrefixes2 = ('<@', '<<', '2>', '>&', '>>', '>@')
+ kRedirectPrefixes3 = ('2>@', '2>>', '>>&', '>&@')
+ kRedirectPrefixes4 = ('2>@1',)
+
+ def __init__(self, args):
+ self.args = iter(args)
+
+ def lex(self):
+ try:
+ return self.args.next()
+ except StopIteration:
+ return None
+
+ def look(self):
+ next = self.lex()
+ if next is not None:
+ self.args = itertools.chain([next], self.args)
+ return next
+
+ def parse_redirect(self, tok, length):
+ if len(tok) == length:
+ arg = self.lex()
+ if arg is None:
+ raise ValueError,'Missing argument to %r redirection' % tok
+ else:
+ tok,arg = tok[:length],tok[length:]
+
+ if tok[0] == '2':
+ op = (tok[1:],2)
+ else:
+ op = (tok,)
+ return (op, arg)
+
+ def parse_pipeline(self):
+ if self.look() is None:
+ raise ValueError,"Expected at least one argument to exec"
+
+ commands = [Command([],[])]
+ while 1:
+ arg = self.lex()
+ if arg is None:
+ break
+ elif arg == '|':
+ commands.append(Command([],[]))
+ elif arg == '|&':
+ # Write this as a redirect of stderr; it must come first because
+ # stdout may have already been redirected.
+ commands[-1].redirects.insert(0, (('>&',2),'1'))
+ commands.append(Command([],[]))
+ elif arg[:4] in TclExecCommand.kRedirectPrefixes4:
+ commands[-1].redirects.append(self.parse_redirect(arg, 4))
+ elif arg[:3] in TclExecCommand.kRedirectPrefixes3:
+ commands[-1].redirects.append(self.parse_redirect(arg, 3))
+ elif arg[:2] in TclExecCommand.kRedirectPrefixes2:
+ commands[-1].redirects.append(self.parse_redirect(arg, 2))
+ elif arg[:1] in TclExecCommand.kRedirectPrefixes1:
+ commands[-1].redirects.append(self.parse_redirect(arg, 1))
+ else:
+ commands[-1].args.append(arg)
+
+ return Pipeline(commands, False, pipe_err=True)
+
+ def parse(self):
+ ignoreStderr = False
+ keepNewline = False
+
+ # Parse arguments.
+ while 1:
+ next = self.look()
+ if not isinstance(next, str) or next[0] != '-':
+ break
+
+ if next == '--':
+ self.lex()
+ break
+ elif next == '-ignorestderr':
+ ignoreStderr = True
+ elif next == '-keepnewline':
+ keepNewline = True
+ else:
+ raise ValueError,"Invalid exec argument %r" % next
+
+ return (ignoreStderr, keepNewline, self.parse_pipeline())
+
+###
+
+import unittest
+
+class TestTclLexer(unittest.TestCase):
+ def lex(self, str, *args, **kwargs):
+ return list(TclLexer(str, *args, **kwargs).lex())
+
+ def test_preprocess(self):
+ self.assertEqual(tcl_preprocess('a b'), 'a b')
+ self.assertEqual(tcl_preprocess('a\\\nb c'), 'a b c')
+
+ def test_unquoted(self):
+ self.assertEqual(self.lex('a b c'),
+ ['a', 'b', 'c'])
+ self.assertEqual(self.lex(r'a\nb\tc\ '),
+ ['a\nb\tc '])
+ self.assertEqual(self.lex(r'a \\\$b c $\\'),
+ ['a', r'\$b', 'c', '$\\'])
+
+ def test_braced(self):
+ self.assertEqual(self.lex('a {b c} {}'),
+ ['a', 'b c', ''])
+ self.assertEqual(self.lex(r'a {b {c\n}}'),
+ ['a', 'b {c\\n}'])
+ self.assertEqual(self.lex(r'a {b\{}'),
+ ['a', 'b{'])
+ self.assertEqual(self.lex(r'{*}'), ['*'])
+ self.assertEqual(self.lex(r'{*} a'), ['*', 'a'])
+ self.assertEqual(self.lex(r'{*} a'), ['*', 'a'])
+ self.assertEqual(self.lex('{a\\\n b}'),
+ ['a b'])
+
+ def test_quoted(self):
+ self.assertEqual(self.lex('a "b c"'),
+ ['a', 'b c'])
+
+ def test_terminators(self):
+ self.assertEqual(self.lex('a\nb'),
+ ['a', (';',), 'b'])
+ self.assertEqual(self.lex('a;b'),
+ ['a', (';',), 'b'])
+ self.assertEqual(self.lex('a ; b'),
+ ['a', (';',), 'b'])
+
+class TestTclExecCommand(unittest.TestCase):
+ def parse(self, str):
+ return TclExecCommand(list(TclLexer(str).lex())).parse()
+
+ def test_basic(self):
+ self.assertEqual(self.parse('echo hello'),
+ (False, False,
+ Pipeline([Command(['echo', 'hello'], [])],
+ False, True)))
+ self.assertEqual(self.parse('echo hello | grep hello'),
+ (False, False,
+ Pipeline([Command(['echo', 'hello'], []),
+ Command(['grep', 'hello'], [])],
+ False, True)))
+
+ def test_redirect(self):
+ self.assertEqual(self.parse('echo hello > a >b >>c 2> d |& e'),
+ (False, False,
+ Pipeline([Command(['echo', 'hello'],
+ [(('>&',2),'1'),
+ (('>',),'a'),
+ (('>',),'b'),
+ (('>>',),'c'),
+ (('>',2),'d')]),
+ Command(['e'], [])],
+ False, True)))
+
+if __name__ == '__main__':
+ unittest.main()
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