Add IDL Lexer

ppapi/generators/idl_lexer.py

+#!/usr/bin/python
+#
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Lexer for PPAPI IDL """
+
+
+import getopt
+import os.path
+import re
+import sys
+
+#
+# Try to load the ply module, if not, then assume it is in the third_party
+# directory, relative to ppapi
+#
+try:
+  from ply import lex
+except:
+  module_path, module_name = os.path.split(__file__)
+  third_party = os.path.join(module_path, '..', '..', 'third_party')
+  sys.path.append(third_party)
+  from ply import lex
+
+#
+# IDL Lexer
+#
+class IDLLexer(object):
+  # 'tokens' is a value required by lex which specifies the complete list
+  # of valid token types.
+  tokens = [
+    # Symbol and keywords types
+      'COMMENT',
+      'DESCRIBE',
+      'ENUM',
+      'SYMBOL',
+      'INTERFACE',
+      'STRUCT',
+      'TYPEDEF',
+
+    # Data types
+      'FLOAT',
+      'INT',
+      'HEX',
+      'STRING',
+
+    # Operators
+      'LSHIFT'
+  ]
+
+  # 'keywords' is a map of string to token type.  All SYMBOL tokens are
+  # matched against keywords, to determine if the token is actually a keyword.
+  keywords = {
+    'describe' : 'DESCRIBE',
+    'enum'  : 'ENUM',
+    'interface' : 'INTERFACE',
+    'readonly' : 'READONLY',
+    'struct' : 'STRUCT',
+    'typedef' : 'TYPEDEF',

[Nick Bray, 2011/03/21 20:25:29]

I believe the style guide says:
'typedef': 'TYPEDEF'
(remove a space)

+  }
+
+  # 'literals' is a value expected by lex which specifies a list of valid
+  # literal tokens, meaning the token type and token value are identical.
+  literals = '"*.(){}[],;:=+-'
+
+  # Token definitions
+  #
+  # Lex assumes any value or function in the form of 't_<TYPE>' represents a
+  # regular expression where a match will emit a token of type <TYPE>.  In the
+  # case of a function, the function is called when a match is made.
+
+  # 't_ignore' is a special match of items to ignore
+  t_ignore = ' \t'
+
+  # Constant values
+  t_FLOAT = r'-?(\d+\.\d*|\d*\.\d+)([Ee][+-]?\d+)?|-?\d+[Ee][+-]?\d+'
+  t_HEX = r'0x[a-fA-F0-9]+'
+  t_INT = r'-?\d+'
+  t_LSHIFT = r'<<'
+
+  # A line ending '\n', we use this to increment the line number
+  def t_LINE_END(self, t):
+    r'\n+'
+    self.AddLines(len(t.value))
+
+  # We do not process escapes in the IDL strings.  Strings are exclusively
+  # used for attributes, and not used as typical 'C' constants.
+  def t_STRING(self, t):
+    r'"[^"]*"'
+    t.value = t.value[1:-1]
+    self.AddLines(t.value.count('\n'))
+    return t
+
+  # A C or C++ style comment:  /* xxx */ or //
+  def t_COMMENT(self, t):
+    r'(/\*(.|\n)*?\*/)|(//.*)'
+    self.AddLines(t.value.count('\n'))
+
+    # C++ comments should keep the newline
+    if t.value[:2] == '//': t.value += '\n'
+    return t
+
+  # A symbol or keyword.
+  def t_KEYWORD_SYMBOL(self, t):
+    r'[A-Za-z][A-Za-z_0-9]*'
+
+    #All non-keywords are assumed to be symbols
+    t.type = self.keywords.get(t.value, 'SYMBOL')
+    return t
+
+  def t_ANY_error(self, t):
+    line = self.lexobj.lineno
+    pos = self.lexobj.lexpos - self.index[line]
+    file = self.lexobj.filename
+    out = self.ErrorMessage(file, line, pos, "Unrecognized input")
+    sys.stderr.write(out + '\n')
+
+  def AddLines(self, count):
+    # Set the lexer position for the beginning of the next line.  In the case
+    # of multiple lines, tokens can not exist on any of the lines except the
+    # last one, so the recorded value for previous lines are unused.  We still
+    # fill the array however, to make sure the line count is correct.
+    self.lexobj.lineno += count
+    for i in range(count):
+      self.index.append(self.lexobj.lexpos)
+
+  def FileLineMsg(self, file, line, msg):
+    if file:  return "%s(%d) : %s" % (file, line + 1, msg)
+    return "<BuiltIn> : %s" % msg
+
+  def SourceLine(self, file, line, pos):
+    caret = '\t^'.expandtabs(pos)
+    return "%s\n%s" % (self.lines[line], caret)
+
+  def ErrorMessage(self, file, line, pos, msg):
+    return "\n%s\n%s" % (
+        self.FileLineMsg(file, line, msg),
+        self.SourceLine(file, line, pos))
+
+  def SetData(self, filename, data):
+    self.lexobj.filename = filename
+    self.lexobj.lineno = 0
+    self.lines = data.split('\n')
+    self.index = [0]
+    self.lexobj.input(data)
+
+  def __init__(self):
+    self.lexobj = lex.lex(object=self, lextab=None, optimize=0)
+
+
+#
+# FilesToTokens
+#
+# From a set of source file names, generate a list of tokens.
+#
+def FilesToTokens(filenames, verbose=False):

[Nick Bray, 2011/03/21 20:25:29]

Implement this in terms of TextToTokens

+  lexer = IDLLexer()
+  outlist = []
+  for filename in filenames:
+    data = open(filename).read()
+    lexer.SetData(filename, data)
+    if verbose: sys.stdout.write('  Loaded %s...\n' % filename)
+    while 1:
+      t = lexer.lexobj.token()
+      if t is None: break
+      outlist.append(t)
+  return outlist
+
+#
+# TextToTokens
+#
+# From a block of text, generate a list of tokens
+#
+def TextToTokens(source):
+  lexer = IDLLexer()
+  outlist = []
+  lexer.SetData('AUTO', source)
+  while 1:
+    t = lexer.lexobj.token()
+    if t is None: break
+    outlist.append(t.value)
+  return outlist
+
+
+#
+# TestSame
+#
+# From a set of token values, generate a new source text by joining with a
+# single space.  The new source is then tokenized and compared against the
+# old set.
+#
+def TestSame(values, output=False, verbose=False):
+  src1 = ' '.join(values)
+  src2 = ' '.join(TextToTokens(src1))
+
+  if output:
+    sys.stdout.write('Generating original.txt and tokenized.txt\n')
+    open('original.txt', 'w').write(src1)
+    open('tokenized.txt', 'w').write(src2)
+
+  if src1 == src2:
+    sys.stdout.write('Same: Pass\n')
+    return 0
+
+  sys.stdout.write('Same: Failed\n')
+  return -1
+
+
+#
+# TestExpect
+#
+# From a set of tokens pairs, verify the type field of the second matches
+# the value of the first, so that:
+# INT 123 FLOAT 1.1
+# will generate a passing test, where the first token is the SYMBOL INT,
+# and the second token is the INT 123, third token is the SYMBOL FLOAT and
+# the fourth is the FLOAT 1.1, etc...
+def TestExpect(tokens):
+  count = len(tokens)
+  index = 0
+  errors = 0
+  while index < count:
+    type = tokens[index].value
+    token = tokens[index + 1]
+    index += 2
+
+    if type != token.type:
+      sys.stderr.write('Mismatch:  Expected %s, but got %s = %s.' %
+                       (type, token.type, token.value))
+      errors += 1
+
+  if not errors:
+    sys.stdout.write('Expect: Pass\n')
+    return 0
+
+  sys.stdout.write('Expect: Failed\n')
+  return -1
+
+
+
+
+def Main(args):
+  try:
+    long_opts = ['output', 'verbose', 'test_expect', 'test_same']
+    usage = 'Usage: idl_lexer.py %s [<src.idl> ...]' % ' '.join(
+       ['--%s' % opt for opt in long_opts])
+
+    opts, filenames = getopt.getopt(args, '', long_opts)
+  except getopt.error, e:
+    sys.stderr.write('Illegal option: %s\n%s\n' % (str(e), usage))
+    return 1
+
+  output = False
+  test_same = False
+  test_expect = False
+  verbose = False
+
+  for opt, val in opts:
+    if opt == '--output':
+      output = True
+
+    if opt == '--test_expect':
+      test_expect = True
+
+    if opt == '--test_same':
+      test_same = True
+
+    if opt == '--verbose':
+      verbose = True
+
+  try:
+    tokens = FilesToTokens(filenames, verbose)
+    values = [tok.value for tok in tokens]
+    if output: sys.stdout.write(' <> '.join(values) + '\n')
+    if test_same:
+      if TestSame(values, output = output, verbose = verbose):
+        return -1
+
+    if test_expect:
+      if TestExpect(tokens):
+        return -1
+    return 0
+
+  except lex.LexError as le:
+    sys.stderr.write('%s\n' % str(le))
+  return -1
+
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))
+