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| 1 # Copyright 2014 The Chromium Authors. All rights reserved. | |
| 2 # Use of this source code is governed by a BSD-style license that can be | |
| 3 # found in the LICENSE file. | |
| 4 | |
| 5 import re | |
| 6 import sys | |
| 7 import os.path | |
| 8 | |
| 9 # Try to load the ply module, if not, then assume it is in the third_party | |
| 10 # directory. | |
| 11 try: | |
| 12 # Disable lint check which fails to find the ply module. | |
| 13 # pylint: disable=F0401 | |
| 14 from ply.lex import TOKEN | |
| 15 except ImportError: | |
| 16 module_path, module_name = os.path.split(__file__) | |
| 17 third_party = os.path.join(module_path, os.pardir, os.pardir, os.pardir, | |
| 18 os.pardir, os.pardir, 'third_party') | |
| 19 sys.path.append(third_party) | |
| 20 # pylint: disable=F0401 | |
| 21 from ply.lex import TOKEN | |
| 22 | |
| 23 | |
| 24 class LexError(Exception): | |
| 25 def __init__(self, filename, lineno, msg): | |
| 26 self.filename = filename | |
| 27 self.lineno = lineno | |
| 28 self.msg = msg | |
| 29 | |
| 30 def __str__(self): | |
| 31 return "%s:%d: Error: %s" % (self.filename, self.lineno, self.msg) | |
| 32 | |
| 33 def __repr__(self): | |
| 34 return str(self) | |
| 35 | |
| 36 | |
| 37 class Lexer(object): | |
| 38 | |
| 39 def __init__(self, filename): | |
| 40 self.filename = filename | |
| 41 | |
| 42 ######################-- PRIVATE --###################### | |
| 43 | |
| 44 ## | |
| 45 ## Internal auxiliary methods | |
| 46 ## | |
| 47 def _error(self, msg, token): | |
| 48 raise LexError(self.filename, token.lineno, msg) | |
| 49 | |
| 50 ## | |
| 51 ## Reserved keywords | |
| 52 ## | |
| 53 keywords = ( | |
| 54 'HANDLE', | |
| 55 'DATA_PIPE_CONSUMER', | |
| 56 'DATA_PIPE_PRODUCER', | |
| 57 'MESSAGE_PIPE', | |
| 58 'SHARED_BUFFER', | |
| 59 | |
| 60 'IMPORT', | |
| 61 'MODULE', | |
| 62 'STRUCT', | |
| 63 'INTERFACE', | |
| 64 'ENUM', | |
| 65 ) | |
| 66 | |
| 67 keyword_map = {} | |
| 68 for keyword in keywords: | |
| 69 keyword_map[keyword.lower()] = keyword | |
| 70 | |
| 71 ## | |
| 72 ## All the tokens recognized by the lexer | |
| 73 ## | |
| 74 tokens = keywords + ( | |
| 75 # Identifiers | |
| 76 'NAME', | |
| 77 | |
| 78 # Constants | |
| 79 'ORDINAL', | |
| 80 'INT_CONST_DEC', 'INT_CONST_OCT', 'INT_CONST_HEX', | |
| 81 'FLOAT_CONST', | |
| 82 'CHAR_CONST', | |
| 83 | |
| 84 # String literals | |
| 85 'STRING_LITERAL', | |
| 86 | |
| 87 # Operators | |
| 88 'PLUS', 'MINUS', 'TIMES', 'DIVIDE', 'MOD', | |
| 89 'OR', 'AND', 'NOT', 'XOR', 'LSHIFT', 'RSHIFT', | |
| 90 | |
| 91 # Assignment | |
| 92 'EQUALS', | |
| 93 | |
| 94 # Request / response | |
| 95 'RESPONSE', | |
| 96 | |
| 97 # Delimiters | |
| 98 'LPAREN', 'RPAREN', # ( ) | |
| 99 'LBRACKET', 'RBRACKET', # [ ] | |
| 100 'LBRACE', 'RBRACE', # { } | |
| 101 'LANGLE', 'RANGLE', # < > | |
| 102 'SEMI', # ; | |
| 103 'COMMA', 'DOT' # , . | |
| 104 ) | |
| 105 | |
| 106 ## | |
| 107 ## Regexes for use in tokens | |
| 108 ## | |
| 109 | |
| 110 # valid C identifiers (K&R2: A.2.3), plus '$' (supported by some compilers) | |
| 111 identifier = r'[a-zA-Z_$][0-9a-zA-Z_$]*' | |
| 112 | |
| 113 hex_prefix = '0[xX]' | |
| 114 hex_digits = '[0-9a-fA-F]+' | |
| 115 | |
| 116 # integer constants (K&R2: A.2.5.1) | |
| 117 integer_suffix_opt = \ | |
| 118 r'(([uU]ll)|([uU]LL)|(ll[uU]?)|(LL[uU]?)|([uU][lL])|([lL][uU]?)|[uU])?' | |
| 119 decimal_constant = \ | |
| 120 '(0'+integer_suffix_opt+')|([1-9][0-9]*'+integer_suffix_opt+')' | |
| 121 octal_constant = '0[0-7]*'+integer_suffix_opt | |
| 122 hex_constant = hex_prefix+hex_digits+integer_suffix_opt | |
| 123 | |
| 124 bad_octal_constant = '0[0-7]*[89]' | |
| 125 | |
| 126 # character constants (K&R2: A.2.5.2) | |
| 127 # Note: a-zA-Z and '.-~^_!=&;,' are allowed as escape chars to support #line | |
| 128 # directives with Windows paths as filenames (..\..\dir\file) | |
| 129 # For the same reason, decimal_escape allows all digit sequences. We want to | |
| 130 # parse all correct code, even if it means to sometimes parse incorrect | |
| 131 # code. | |
| 132 # | |
| 133 simple_escape = r"""([a-zA-Z._~!=&\^\-\\?'"])""" | |
| 134 decimal_escape = r"""(\d+)""" | |
| 135 hex_escape = r"""(x[0-9a-fA-F]+)""" | |
| 136 bad_escape = r"""([\\][^a-zA-Z._~^!=&\^\-\\?'"x0-7])""" | |
| 137 | |
| 138 escape_sequence = \ | |
| 139 r"""(\\("""+simple_escape+'|'+decimal_escape+'|'+hex_escape+'))' | |
| 140 cconst_char = r"""([^'\\\n]|"""+escape_sequence+')' | |
| 141 char_const = "'"+cconst_char+"'" | |
| 142 unmatched_quote = "('"+cconst_char+"*\\n)|('"+cconst_char+"*$)" | |
| 143 bad_char_const = \ | |
| 144 r"""('"""+cconst_char+"""[^'\n]+')|('')|('"""+ \ | |
| 145 bad_escape+r"""[^'\n]*')""" | |
| 146 | |
| 147 # string literals (K&R2: A.2.6) | |
| 148 string_char = r"""([^"\\\n]|"""+escape_sequence+')' | |
| 149 string_literal = '"'+string_char+'*"' | |
| 150 bad_string_literal = '"'+string_char+'*'+bad_escape+string_char+'*"' | |
| 151 | |
| 152 # floating constants (K&R2: A.2.5.3) | |
| 153 exponent_part = r"""([eE][-+]?[0-9]+)""" | |
| 154 fractional_constant = r"""([0-9]*\.[0-9]+)|([0-9]+\.)""" | |
| 155 floating_constant = \ | |
| 156 '(((('+fractional_constant+')'+ \ | |
| 157 exponent_part+'?)|([0-9]+'+exponent_part+')))' | |
| 158 | |
| 159 # Ordinals | |
| 160 ordinal = r'@[0-9]+' | |
| 161 missing_ordinal_value = r'@' | |
| 162 # Don't allow ordinal values in octal (even invalid octal, like 09) or | |
| 163 # hexadecimal. | |
| 164 octal_or_hex_ordinal_disallowed = r'@((0[0-9]+)|('+hex_prefix+hex_digits+'))' | |
| 165 | |
| 166 ## | |
| 167 ## Rules for the normal state | |
| 168 ## | |
| 169 t_ignore = ' \t\r' | |
| 170 | |
| 171 # Newlines | |
| 172 def t_NEWLINE(self, t): | |
| 173 r'\n+' | |
| 174 t.lexer.lineno += t.value.count("\n") | |
| 175 | |
| 176 # Operators | |
| 177 t_PLUS = r'\+' | |
| 178 t_MINUS = r'-' | |
| 179 t_TIMES = r'\*' | |
| 180 t_DIVIDE = r'/' | |
| 181 t_MOD = r'%' | |
| 182 t_OR = r'\|' | |
| 183 t_AND = r'&' | |
| 184 t_NOT = r'~' | |
| 185 t_XOR = r'\^' | |
| 186 t_LSHIFT = r'<<' | |
| 187 t_RSHIFT = r'>>' | |
| 188 | |
| 189 # = | |
| 190 t_EQUALS = r'=' | |
| 191 | |
| 192 # => | |
| 193 t_RESPONSE = r'=>' | |
| 194 | |
| 195 # Delimiters | |
| 196 t_LPAREN = r'\(' | |
| 197 t_RPAREN = r'\)' | |
| 198 t_LBRACKET = r'\[' | |
| 199 t_RBRACKET = r'\]' | |
| 200 t_LBRACE = r'\{' | |
| 201 t_RBRACE = r'\}' | |
| 202 t_LANGLE = r'<' | |
| 203 t_RANGLE = r'>' | |
| 204 t_COMMA = r',' | |
| 205 t_DOT = r'\.' | |
| 206 t_SEMI = r';' | |
| 207 | |
| 208 t_STRING_LITERAL = string_literal | |
| 209 | |
| 210 # The following floating and integer constants are defined as | |
| 211 # functions to impose a strict order (otherwise, decimal | |
| 212 # is placed before the others because its regex is longer, | |
| 213 # and this is bad) | |
| 214 # | |
| 215 @TOKEN(floating_constant) | |
| 216 def t_FLOAT_CONST(self, t): | |
| 217 return t | |
| 218 | |
| 219 @TOKEN(hex_constant) | |
| 220 def t_INT_CONST_HEX(self, t): | |
| 221 return t | |
| 222 | |
| 223 @TOKEN(bad_octal_constant) | |
| 224 def t_BAD_CONST_OCT(self, t): | |
| 225 msg = "Invalid octal constant" | |
| 226 self._error(msg, t) | |
| 227 | |
| 228 @TOKEN(octal_constant) | |
| 229 def t_INT_CONST_OCT(self, t): | |
| 230 return t | |
| 231 | |
| 232 @TOKEN(decimal_constant) | |
| 233 def t_INT_CONST_DEC(self, t): | |
| 234 return t | |
| 235 | |
| 236 # Must come before bad_char_const, to prevent it from | |
| 237 # catching valid char constants as invalid | |
| 238 # | |
| 239 @TOKEN(char_const) | |
| 240 def t_CHAR_CONST(self, t): | |
| 241 return t | |
| 242 | |
| 243 @TOKEN(unmatched_quote) | |
| 244 def t_UNMATCHED_QUOTE(self, t): | |
| 245 msg = "Unmatched '" | |
| 246 self._error(msg, t) | |
| 247 | |
| 248 @TOKEN(bad_char_const) | |
| 249 def t_BAD_CHAR_CONST(self, t): | |
| 250 msg = "Invalid char constant %s" % t.value | |
| 251 self._error(msg, t) | |
| 252 | |
| 253 # unmatched string literals are caught by the preprocessor | |
| 254 | |
| 255 @TOKEN(bad_string_literal) | |
| 256 def t_BAD_STRING_LITERAL(self, t): | |
| 257 msg = "String contains invalid escape code" | |
| 258 self._error(msg, t) | |
| 259 | |
| 260 # Handle ordinal-related tokens in the right order: | |
| 261 @TOKEN(octal_or_hex_ordinal_disallowed) | |
| 262 def t_OCTAL_OR_HEX_ORDINAL_DISALLOWED(self, t): | |
| 263 msg = "Octal and hexadecimal ordinal values not allowed" | |
| 264 self._error(msg, t) | |
| 265 | |
| 266 @TOKEN(ordinal) | |
| 267 def t_ORDINAL(self, t): | |
| 268 return t | |
| 269 | |
| 270 @TOKEN(missing_ordinal_value) | |
| 271 def t_BAD_ORDINAL(self, t): | |
| 272 msg = "Missing ordinal value" | |
| 273 self._error(msg, t) | |
| 274 | |
| 275 @TOKEN(identifier) | |
| 276 def t_NAME(self, t): | |
| 277 t.type = self.keyword_map.get(t.value, "NAME") | |
| 278 return t | |
| 279 | |
| 280 # Ignore C and C++ style comments | |
| 281 def t_COMMENT(self, t): | |
| 282 r'(/\*(.|\n)*?\*/)|(//.*(\n[ \t]*//.*)*)' | |
| 283 pass | |
| 284 | |
| 285 def t_error(self, t): | |
| 286 msg = 'Illegal character %s' % repr(t.value[0]) | |
| 287 self._error(msg, t) | |
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