vendor/rails/activesupport/lib/active_support/json/decoding.rb

   1 require 'yaml'
   2 require 'strscan'
   3
   4 module ActiveSupport
   5   module JSON
   6     class ParseError < StandardError
   7     end
   8
   9     class << self
  10       # Converts a JSON string into a Ruby object.
  11       def decode(json)
  12         YAML.load(convert_json_to_yaml(json))
  13       rescue ArgumentError => e
  14         raise ParseError, "Invalid JSON string"
  15       end
  16
  17       protected
  18         # matches YAML-formatted dates
  19         DATE_REGEX = /^(?:\d{4}-\d{2}-\d{2}|\d{4}-\d{1,2}-\d{1,2}[ \t]+\d{1,2}:\d{2}:\d{2}(\.[0-9]*)?(([ \t]*)Z|[-+]\d{2}?(:\d{2})?)?)$/
  20
  21         # Ensure that ":" and "," are always followed by a space
  22         def convert_json_to_yaml(json) #:nodoc:
  23           scanner, quoting, marks, pos, times = StringScanner.new(json), false, [], nil, []
  24           while scanner.scan_until(/(\\['"]|['":,\\]|\\.)/)
  25             case char = scanner[1]
  26             when '"', "'"
  27               if !quoting
  28                 quoting = char
  29                 pos = scanner.pos
  30               elsif quoting == char
  31                 if json[pos..scanner.pos-2] =~ DATE_REGEX
  32                   # found a date, track the exact positions of the quotes so we can remove them later.
  33                   # oh, and increment them for each current mark, each one is an extra padded space that bumps
  34                   # the position in the final YAML output
  35                   total_marks = marks.size
  36                   times << pos+total_marks << scanner.pos+total_marks
  37                 end
  38                 quoting = false
  39               end
  40             when ":",","
  41               marks << scanner.pos - 1 unless quoting
  42             end
  43           end
  44
  45           if marks.empty?
  46             json.gsub(/\\([\\\/]|u[[:xdigit:]]{4})/) do
  47               ustr = $1
  48               if ustr.starts_with?('u')
  49                 [ustr[1..-1].to_i(16)].pack("U")
  50               elsif ustr == '\\'
  51                 '\\\\'
  52               else
  53                 ustr
  54               end
  55             end
  56           else
  57             left_pos  = [-1].push(*marks)
  58             right_pos = marks << scanner.pos + scanner.rest_size
  59             output    = []
  60             left_pos.each_with_index do |left, i|
  61               scanner.pos = left.succ
  62               output << scanner.peek(right_pos[i] - scanner.pos + 1).gsub(/\\([\\\/]|u[[:xdigit:]]{4})/) do
  63                 ustr = $1
  64                 if ustr.starts_with?('u')
  65                   [ustr[1..-1].to_i(16)].pack("U")
  66                 elsif ustr == '\\'
  67                 '\\\\'
  68                 else
  69                   ustr
  70                 end
  71               end
  72             end
  73             output = output * " "
  74
  75             times.each { |i| output[i-1] = ' ' }
  76             output.gsub!(/\\\//, '/')
  77             output
  78           end
  79         end
  80     end
  81   end
  82 end