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

60 lines
2 KiB
Ruby

require 'yaml'
require 'strscan'
module ActiveSupport
module JSON
class ParseError < StandardError
end
class << 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
# matches YAML-formatted dates
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})?)?$/
# Ensure that ":" and "," are always followed by a space
def convert_json_to_yaml(json) #:nodoc:
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
end
end
if marks.empty?
json.gsub(/\\\//, '/')
else
# FIXME: multiple slow enumerations
output = ([0] + marks.map(&:succ)).
zip(marks + [json.length]).
map { |left, right| json[left..right] }.
join(" ")
times.each { |i| output[i-1] = ' ' }
output.gsub!(/\\\//, '/')
output
end
end
end
end
end