text: #!/usr/bin/env python
  #
  # Copyright (C) 2012 The Android Open Source Project
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  """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+(class\s+)?(\S+)\s+:?.*\{(\s+// private)?')
  _ENUM_VALUE_RE = re.compile(r'([A-Za-z0-9_]+)(.*)')
  _ENUM_END_RE = re.compile(r'^\s*\};$')
  _ENUMS = {}
  _NAMESPACES = {}
  _ENUM_CLASSES = {}
  
  def Confused(filename, line_number, line):
    sys.stderr.write('%s:%d: confused by:\n%s\n' % (filename, line_number, line))
    raise Exception("giving up!")
    sys.exit(1)
  
  
  def ProcessFile(filename):
    lines = codecs.open(filename, 'r', 'utf8', 'replace').read().split('\n')
    in_enum = False
    is_enum_private = False
    is_enum_class = False
    line_number = 0
    
  
    namespaces = []
    enclosing_classes = []
  
    for raw_line in lines:
      line_number += 1
  
      if not in_enum:
        # Is this the start of a new enum?
        m = _ENUM_START_RE.search(raw_line)
        if m:
          # Yes, so add an empty entry to _ENUMS for this enum.
          
          # Except when it's private
          if m.group(3) is not None:
            is_enum_private = True
          else:
            is_enum_private = False
            is_enum_class = m.group(1) is not None
            enum_name = m.group(2)
            if len(enclosing_classes) > 0:
              enum_name = '::'.join(enclosing_classes) + '::' + enum_name
            _ENUMS[enum_name] = []
            _NAMESPACES[enum_name] = '::'.join(namespaces)
            _ENUM_CLASSES[enum_name] = is_enum_class
          in_enum = True
          continue
  
        # Is this the start or end of a namespace?
        m = re.compile(r'^namespace (\S+) \{').search(raw_line)
        if m:
          namespaces.append(m.group(1))
          continue
        m = re.compile(r'^\}\s+// namespace').search(raw_line)
        if m:
          namespaces = namespaces[0:len(namespaces) - 1]
          continue
  
        # Is this the start or end of an enclosing class or struct?
        m = re.compile(r'^\s*(?:class|struct)(?: MANAGED)?(?: PACKED\([0-9]\))? (\S+).* \{').search(raw_line)
        if m:
          enclosing_classes.append(m.group(1))
          continue
  
        # End of class/struct -- be careful not to match "do { ... } while" constructs by accident
        m = re.compile(r'^\s*\}(\s+)?(while)?(.+)?;').search(raw_line)
        if m and not m.group(2):
          enclosing_classes = enclosing_classes[0:len(enclosing_classes) - 1]
          continue
  
        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
  
      if is_enum_private:
        continue
  
      # The only useful thing in comments is the <<alternate text>> syntax for
      # overriding the default enum value names. Pull that out...
      enum_text = None
      m_comment = re.compile(r'// <<(.*?)>>').search(raw_line)
      if m_comment:
        enum_text = m_comment.group(1)
      # ...and then strip // comments.
      line = re.sub(r'//.*', '', raw_line)
  
      # Strip whitespace.
      line = line.strip()
  
      # Skip blank lines.
      if len(line) == 0:
        continue
  
      # Since we know we're in an enum type, and we're not looking at a comment
      # or a blank line, this line should be the next enum value...
      m = _ENUM_VALUE_RE.search(line)
      if not m:
        Confused(filename, line_number, raw_line)
      enum_value = m.group(1)
  
      # By default, we turn "kSomeValue" into "SomeValue".
      if enum_text == None:
        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()
  
      # There shouldn't be anything left.
      if len(rest):
        sys.stderr.write('%s\n' % (rest))
        Confused(filename, line_number, raw_line)
  
      # If the enum is scoped, we must prefix enum value with enum name (which is already prefixed
      # by enclosing classes).
      if is_enum_class:
        enum_value = enum_name + '::' + enum_value
      else:
        if len(enclosing_classes) > 0:
          enum_value = '::'.join(enclosing_classes) + '::' + enum_value
  
      _ENUMS[enum_name].append((enum_value, enum_text))
  
  def main():
    local_path = sys.argv[1]
    header_files = []
    for header_file in sys.argv[2:]:
      header_files.append(header_file)
      ProcessFile(header_file)
  
    print('#include <iostream>')
    print('')
  
    for header_file in header_files:
      header_file = header_file.replace(local_path + '/', '')
      print('#include "%s"' % header_file)
  
    print('')
  
    for enum_name in _ENUMS:
      print('// This was automatically generated by %s --- do not edit!' % sys.argv[0])
  
      namespaces = _NAMESPACES[enum_name].split('::')
      for namespace in namespaces:
        print('namespace %s {' % namespace)
  
      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))
      if not _ENUM_CLASSES[enum_name]:
        print('    default: os << "%s[" << static_cast<int>(rhs) << "]"; break;' % enum_name)
      print('  }')
      print('  return os;')
      print('}')
  
      for namespace in reversed(namespaces):
        print('}  // namespace %s' % namespace)
      print('')
  
    sys.exit(0)
  
  
  if __name__ == '__main__':
    main()
  