module RDoc::Encoding

This class is a wrapper around File IO and Encoding that helps RDoc load files and convert them to the correct encoding.

Public Class Methods

change_encoding (text, encoding)

Changes encoding based on encoding without converting and returns new string

# File lib/rdoc/encoding.rb, line 113
def self.change_encoding(text, encoding)
  if text.kind_of? Comment
    text.encode! encoding
  else
    String.new text, encoding: encoding
  end
end
detect_encoding (string)

Detects the encoding of string based on the magic comment

# File lib/rdoc/encoding.rb, line 93
def self.detect_encoding(string)
  result = HEADER_REGEXP.match string
  name = result && result[:name]

  name ? ::Encoding.find(name) : nil
end
read_file (filename, encoding, force_transcode = false)

Reads the contents of filename and handles any encoding directives in the file.

The content will be converted to the encoding. If the file cannot be converted a warning will be printed and nil will be returned.

If force_transcode is true the document will be transcoded and any unknown character in the target encoding will be replaced with ‘?’

# File lib/rdoc/encoding.rb, line 33
def self.read_file(filename, encoding, force_transcode = false)
  content = File.open filename, "rb" do |f| f.read end
  content.gsub!("\r\n", "\n") if RUBY_PLATFORM =~ /mswin|mingw/

  utf8 = content.sub!(/\A\xef\xbb\xbf/, '')

  enc = Encoding.detect_encoding content
  content = Encoding.change_encoding content, enc if enc

  begin
    encoding ||= ::Encoding.default_external
    orig_encoding = content.encoding

    if not orig_encoding.ascii_compatible?
      content = content.encode encoding
    elsif utf8
      content = Encoding.change_encoding content, ::Encoding::UTF_8
      content = content.encode encoding
    else
      # assume the content is in our output encoding
      content = Encoding.change_encoding content, encoding
    end

    unless content.valid_encoding?
      # revert and try to transcode
      content = Encoding.change_encoding content, orig_encoding
      content = content.encode encoding
    end

    unless content.valid_encoding?
      warn "unable to convert #{filename} to #{encoding}, skipping"
      content = nil
    end
  rescue ::Encoding::InvalidByteSequenceError,
         ::Encoding::UndefinedConversionError => e
    if force_transcode
      content = Encoding.change_encoding content, orig_encoding
      content = content.encode(encoding,
                               :invalid => :replace,
                               :undef => :replace,
                               :replace => '?')
      return content
    else
      warn "unable to convert #{e.message} for #{filename}, skipping"
      return nil
    end
  end

  content
rescue ArgumentError => e
  raise unless e.message =~ /unknown encoding name - (.*)/
  warn "unknown encoding name \"#{$1}\" for #{filename}, skipping"
  nil
rescue Errno::EISDIR, Errno::ENOENT
  nil
end
remove_magic_comment (string)

Removes magic comments and shebang

# File lib/rdoc/encoding.rb, line 103
def self.remove_magic_comment(string)
  string.sub HEADER_REGEXP do |s|
    s.gsub(/[^\n]/, '')
  end
end