1 files changed, 40 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/json/decoding.rb b/activesupport/lib/active_support/json/decoding.rb
new file mode 100644
index 0000000000..60003a94e5
--- /dev/null
+++ b/activesupport/lib/active_support/json/decoding.rb
@@ -0,0 +1,40 @@
+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
+        # Ensure that ":" and "," are always followed by a space
+        def convert_json_to_yaml(json) #:nodoc:
+          scanner, quoting, marks = StringScanner.new(json), false, []
+
+          while scanner.scan_until(/(['":,]|\\.)/)
+            case char = scanner[1]
+            when '"', "'"
+              quoting = quoting == char ? false : char
+            when ":", ","
+              marks << scanner.pos - 1 unless quoting
+            end
+          end
+          
+          if marks.empty?
+            json
+          else
+            ranges = ([0] + marks.map(&:succ)).zip(marks + [json.length])
+            ranges.map { |(left, right)| json[left..right] }.join(" ")
+          end
+        end  
+    end
+  end
+end