| from __future__ import absolute_import |
| import itertools |
| |
| import lit.util |
| from lit.ShCommands import Command, GlobItem, Pipeline, Seq |
| |
| class ShLexer: |
| def __init__(self, data, win32Escapes = False): |
| self.data = data |
| self.pos = 0 |
| self.end = len(data) |
| self.win32Escapes = win32Escapes |
| |
| 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 lex_arg_fast(self, c): |
| # Get the leading whitespace free section. |
| chunk = self.data[self.pos - 1:].split(None, 1)[0] |
| |
| # If it has special characters, the fast path failed. |
| if ('|' in chunk or '&' in chunk or |
| '<' in chunk or '>' in chunk or |
| "'" in chunk or '"' in chunk or |
| ';' in chunk or '\\' in chunk): |
| return None |
| |
| self.pos = self.pos - 1 + len(chunk) |
| return GlobItem(chunk) if '*' in chunk or '?' in chunk else chunk |
| |
| def lex_arg_slow(self, c): |
| if c in "'\"": |
| str = self.lex_arg_quoted(c) |
| else: |
| str = c |
| unquoted_glob_char = False |
| quoted_glob_char = False |
| while self.pos != self.end: |
| c = self.look() |
| if c.isspace() or c in "|&;": |
| break |
| elif c in '><': |
| # This is an annoying case; we treat '2>' as a single token so |
| # we don't have to track whitespace tokens. |
| |
| # If the parse string isn't an integer, do the usual thing. |
| if not str.isdigit(): |
| break |
| |
| # Otherwise, lex the operator and convert to a redirection |
| # token. |
| num = int(str) |
| tok = self.lex_one_token() |
| assert isinstance(tok, tuple) and len(tok) == 1 |
| return (tok[0], num) |
| elif c == '"' or c == "'": |
| self.eat() |
| quoted_arg = self.lex_arg_quoted(c) |
| if '*' in quoted_arg or '?' in quoted_arg: |
| quoted_glob_char = True |
| str += quoted_arg |
| elif not self.win32Escapes and c == '\\': |
| # Outside of a string, '\\' escapes everything. |
| self.eat() |
| if self.pos == self.end: |
| lit.util.warning( |
| "escape at end of quoted argument in: %r" % self.data) |
| return str |
| str += self.eat() |
| elif c in '*?': |
| unquoted_glob_char = True |
| str += self.eat() |
| else: |
| str += self.eat() |
| # If a quote character is present, lex_arg_quoted will remove the quotes |
| # and append the argument directly. This causes a problem when the |
| # quoted portion contains a glob character, as the character will no |
| # longer be treated literally. If glob characters occur *only* inside |
| # of quotes, then we can handle this by not globbing at all, and if |
| # glob characters occur *only* outside of quotes, we can still glob just |
| # fine. But if a glob character occurs both inside and outside of |
| # quotes this presents a problem. In practice this is such an obscure |
| # edge case that it doesn't seem worth the added complexity to support. |
| # By adding an assertion, it means some bot somewhere will catch this |
| # and flag the user of a non-portable test (which could almost certainly |
| # be re-written to work correctly without triggering this). |
| assert not (quoted_glob_char and unquoted_glob_char) |
| return GlobItem(str) if unquoted_glob_char else str |
| |
| def lex_arg_quoted(self, delim): |
| str = '' |
| while self.pos != self.end: |
| c = self.eat() |
| if c == delim: |
| return str |
| elif c == '\\' and delim == '"': |
| # Inside a '"' quoted string, '\\' only escapes the quote |
| # character and backslash, otherwise it is preserved. |
| if self.pos == self.end: |
| lit.util.warning( |
| "escape at end of quoted argument in: %r" % self.data) |
| return str |
| c = self.eat() |
| if c == '"': # |
| str += '"' |
| elif c == '\\': |
| str += '\\' |
| else: |
| str += '\\' + c |
| else: |
| str += c |
| lit.util.warning("missing quote character in %r" % self.data) |
| return str |
| |
| def lex_arg_checked(self, c): |
| pos = self.pos |
| res = self.lex_arg_fast(c) |
| end = self.pos |
| |
| self.pos = pos |
| reference = self.lex_arg_slow(c) |
| if res is not None: |
| if res != reference: |
| raise ValueError("Fast path failure: %r != %r" % ( |
| res, reference)) |
| if self.pos != end: |
| raise ValueError("Fast path failure: %r != %r" % ( |
| self.pos, end)) |
| return reference |
| |
| def lex_arg(self, c): |
| return self.lex_arg_fast(c) or self.lex_arg_slow(c) |
| |
| def lex_one_token(self): |
| """ |
| lex_one_token - Lex a single 'sh' token. """ |
| |
| c = self.eat() |
| if c == ';': |
| return (c,) |
| if c == '|': |
| if self.maybe_eat('|'): |
| return ('||',) |
| return (c,) |
| if c == '&': |
| if self.maybe_eat('&'): |
| return ('&&',) |
| if self.maybe_eat('>'): |
| return ('&>',) |
| return (c,) |
| if c == '>': |
| if self.maybe_eat('&'): |
| return ('>&',) |
| if self.maybe_eat('>'): |
| return ('>>',) |
| return (c,) |
| if c == '<': |
| if self.maybe_eat('&'): |
| return ('<&',) |
| if self.maybe_eat('>'): |
| return ('<<',) |
| return (c,) |
| |
| return self.lex_arg(c) |
| |
| def lex(self): |
| while self.pos != self.end: |
| if self.look().isspace(): |
| self.eat() |
| else: |
| yield self.lex_one_token() |
| |
| ### |
| |
| class ShParser: |
| def __init__(self, data, win32Escapes = False, pipefail = False): |
| self.data = data |
| self.pipefail = pipefail |
| self.tokens = ShLexer(data, win32Escapes = win32Escapes).lex() |
| |
| def lex(self): |
| for item in self.tokens: |
| return item |
| return None |
| |
| def look(self): |
| token = self.lex() |
| if token is not None: |
| self.tokens = itertools.chain([token], self.tokens) |
| return token |
| |
| def parse_command(self): |
| tok = self.lex() |
| if not tok: |
| raise ValueError("empty command!") |
| if isinstance(tok, tuple): |
| raise ValueError("syntax error near unexpected token %r" % tok[0]) |
| |
| args = [tok] |
| redirects = [] |
| while 1: |
| tok = self.look() |
| |
| # EOF? |
| if tok is None: |
| break |
| |
| # If this is an argument, just add it to the current command. |
| if isinstance(tok, (str, GlobItem)): |
| args.append(self.lex()) |
| continue |
| |
| # Otherwise see if it is a terminator. |
| assert isinstance(tok, tuple) |
| if tok[0] in ('|',';','&','||','&&'): |
| break |
| |
| # Otherwise it must be a redirection. |
| op = self.lex() |
| arg = self.lex() |
| if not arg: |
| raise ValueError("syntax error near token %r" % op[0]) |
| redirects.append((op, arg)) |
| |
| return Command(args, redirects) |
| |
| def parse_pipeline(self): |
| negate = False |
| |
| commands = [self.parse_command()] |
| while self.look() == ('|',): |
| self.lex() |
| commands.append(self.parse_command()) |
| return Pipeline(commands, negate, self.pipefail) |
| |
| def parse(self): |
| lhs = self.parse_pipeline() |
| |
| while self.look(): |
| operator = self.lex() |
| assert isinstance(operator, tuple) and len(operator) == 1 |
| |
| if not self.look(): |
| raise ValueError( |
| "missing argument to operator %r" % operator[0]) |
| |
| # FIXME: Operator precedence!! |
| lhs = Seq(lhs, operator[0], self.parse_pipeline()) |
| |
| return lhs |
| |
