tools/generate-operator-out.py

#!/usr/bin/python2.4
#
# Copyright 2012 Google Inc. All Rights Reserved.
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"""Generates default implementations of operator<< for enum types."""

import codecs
import os
import re
import string
import sys


_ENUM_START_RE = re.compile(r'\benum\b\s+(\S+)\s+\{')
_ENUM_VALUE_RE = re.compile(r'([A-Za-z0-9_]+)(.*)')
_ENUM_END_RE = re.compile(r'^\s*\};$')
_ENUMS = {}

def Confused(filename, line_number, line):
  sys.stderr.write('%s:%d: confused by:\n%s\n' % (filename, line_number, line))
  sys.exit(1)


def ProcessFile(filename):
  lines = codecs.open(filename, 'r', 'utf8', 'replace').read().split('\n')
  in_enum = False
  line_number = 0
  for raw_line in lines:
    line_number += 1

    # TODO: take namespaces and enclosing classes/structs into account.

    # Is this the start of a new enum?
    if not in_enum:
      m = _ENUM_START_RE.search(raw_line)
      if m:
        # Yes, so add an empty entry to _ENUMS for this enum.
        enum_name = m.group(1)
        _ENUMS[enum_name] = []
        in_enum = True
      continue

    # Is this the end of the current enum?
    m = _ENUM_END_RE.search(raw_line)
    if m:
      if not in_enum:
        Confused(filename, line_number, raw_line)
      in_enum = False
      continue

    # Is this another enum value?
    m = _ENUM_VALUE_RE.search(raw_line.strip())
    if not m:
      Confused(filename, line_number, raw_line)

    enum_value = m.group(1)

    # By default, we turn "kSomeValue" into "SomeValue".
    enum_text = enum_value
    if enum_text.startswith('k'):
      enum_text = enum_text[1:]

    # Lose literal values because we don't care; turn "= 123, // blah" into ", // blah".
    rest = m.group(2).strip()
    m_literal = re.compile(r'= (0x[0-9a-f]+|-?[0-9]+)').search(rest)
    if m_literal:
      rest = rest[(len(m_literal.group(0))):]

    # With "kSomeValue = kOtherValue," we take the original and skip later synonyms.
    # TODO: check that the rhs is actually an existing value.
    if rest.startswith('= k'):
      continue

    # Remove any trailing comma and whitespace
    if rest.startswith(','):
      rest = rest[1:]
    rest = rest.strip()

    # Anything left should be a comment.
    if len(rest) and not rest.startswith('// '):
      print rest
      Confused(filename, line_number, raw_line)

    m_comment = re.compile(r'<<(.*?)>>').search(rest)
    if m_comment:
      enum_text = m_comment.group(1)

    _ENUMS[enum_name].append((enum_value, enum_text))

def main():
  header_files = []
  for header_file in sys.argv[1:]:
    header_files.append(header_file)
    ProcessFile(header_file)

  print '#include <iostream>'
  print

  for header_file in header_files:
    print '#include "%s"' % header_file

  print
  print 'namespace art {'
  print

  for enum_name in _ENUMS:
    print '// This was automatically generated by %s --- do not edit!' % sys.argv[0]
    print 'std::ostream& operator<<(std::ostream& os, const %s& rhs) {' % enum_name
    print '  switch (rhs) {'
    for (enum_value, enum_text) in _ENUMS[enum_name]:
      print '    case %s: os << "%s"; break;' % (enum_value, enum_text)
    print '    default: os << "%s[" << static_cast<int>(rhs) << "]"; break;' % enum_name
    print '  }'
    print '  return os;'
    print '}'
    print

  print '} // namespace art'

  sys.exit(0)


if __name__ == '__main__':
  main()