Module: AddMagicComment

Defined in:
lib/add_magic_comment.rb

Overview

A simple library to prepend magic comments to all Ruby files in a given folder

Constant Summary collapse

MAGIC_COMMENT_PREFIX = 
"frozen_string_literal".freeze
MAGIC_COMMENT_PATTERN = 
/^(-|(<%))?#\s*#{MAGIC_COMMENT_PREFIX}\s*(%>)?/
MAGIC_COMMENT = 
"#{MAGIC_COMMENT_PREFIX}: true".freeze
EMPTY_LINE_PATTERN = 
/^\s$/
SHEBANG_PATTERN = 
/^#!/
EXTENSION_COMMENTS = 
{
  "*.rb"        => "# #{MAGIC_COMMENT}\n\n",
  "*.ru"        => "# #{MAGIC_COMMENT}\n\n",
  "Rakefile"    => "# #{MAGIC_COMMENT}\n\n",
  "*.rake"      => "# #{MAGIC_COMMENT}\n\n",
  "Gemfile"     => "# #{MAGIC_COMMENT}\n\n",
  "*.gemspec"   => "# #{MAGIC_COMMENT}\n\n",
  "*.rabl"      => "# #{MAGIC_COMMENT}\n\n",
  "*.jbuilder"  => "# #{MAGIC_COMMENT}\n\n",
  "*.haml"      => "-# #{MAGIC_COMMENT}\n",
  "*.slim"      => "-# #{MAGIC_COMMENT}\n"
}

Class Method Summary collapse

Class Method Details

.detect_newline(line) ⇒ Object 



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# File 'lib/add_magic_comment.rb', line 65

def self.detect_newline(line)
  (line[/\R/] if line) || $/
end

.process(argv) ⇒ Object 



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# File 'lib/add_magic_comment.rb', line 25

def self.process(argv)
  directory = argv.first || Dir.pwd

  count = 0
  EXTENSION_COMMENTS.each do |pattern, comment|
    filename_pattern = File.join(directory, "**", "#{pattern}")
    Dir.glob(filename_pattern).each do |filename|
      File.open(filename, "rb+") do |file|
        lines = file.readlines
        newline = detect_newline(lines.first)
        next unless lines.any?
        count += 1

        if lines.first =~ SHEBANG_PATTERN
          shebang = lines.shift
        end

        # remove current magic comment(s)
        while lines.first && (lines.first.match(MAGIC_COMMENT_PATTERN) || lines.first.match(EMPTY_LINE_PATTERN))
          lines.shift
        end

        # add magic comment as the first line
        lines.unshift(comment.gsub("\n", newline))

        # put shebang back
        if shebang
          lines.unshift(shebang)
        end

        file.pos = 0
        file.print(*lines)
        file.truncate(file.pos)
      end
    end
  end

  puts "Magic comments added to #{count} source file(s)"
end