~michaelforrest/use-case-mapper/trunk

require 'active_support/core_ext/string/starts_ends_with'

 

module ActiveSupport

  module JSON

    module Backends

      module Yaml

        ParseError = ::StandardError

        extend self

 

        # Converts a JSON string into a Ruby object.

        def decode(json)

          YAML.load(convert_json_to_yaml(json))

        rescue ArgumentError => e

          raise ParseError, "Invalid JSON string"

        end

 

        protected

          # Ensure that ":" and "," are always followed by a space

          def convert_json_to_yaml(json) #:nodoc:

            require 'strscan' unless defined? ::StringScanner

            scanner, quoting, marks, pos, times = ::StringScanner.new(json), false, [], nil, []

            while scanner.scan_until(/(\\['"]|['":,\\]|\\.)/)

              case char = scanner[1]

              when '"', "'"

                if !quoting

                  quoting = char

                  pos = scanner.pos

                elsif quoting == char

                  if json[pos..scanner.pos-2] =~ DATE_REGEX

                    # found a date, track the exact positions of the quotes so we can remove them later.

                    # oh, and increment them for each current mark, each one is an extra padded space that bumps

                    # the position in the final YAML output

                    total_marks = marks.size

                    times << pos+total_marks << scanner.pos+total_marks

                  end

                  quoting = false

                end

              when ":",","

                marks << scanner.pos - 1 unless quoting

              when "\\"

                scanner.skip(/\\/)

              end

            end

 

            if marks.empty?

              json.gsub(/\\([\\\/]|u[[:xdigit:]]{4})/) do

                ustr = $1

                if ustr.start_with?('u')

                  [ustr[1..-1].to_i(16)].pack("U")

                elsif ustr == '\\'

                  '\\\\'

                else

                  ustr

                end

              end

            else

              left_pos  = [-1].push(*marks)

              right_pos = marks << scanner.pos + scanner.rest_size

              output    = []

              left_pos.each_with_index do |left, i|

                scanner.pos = left.succ

                output << scanner.peek(right_pos[i] - scanner.pos + 1).gsub(/\\([\\\/]|u[[:xdigit:]]{4})/) do

                  ustr = $1

                  if ustr.start_with?('u')

                    [ustr[1..-1].to_i(16)].pack("U")

                  elsif ustr == '\\'

                    '\\\\'

                  else

                    ustr

                  end

                end

              end

              output = output * " "

 

              times.each { |i| output[i-1] = ' ' }

              output.gsub!(/\\\//, '/')

              output

            end

          end

      end

    end

  end

end