NSJSONSerialization support for MacRuby

Implemented NSJSONSerialization as a subclass of MultiJson::Engines::OKJson for best compatibility to the MultiJson spec.
:nsjsonserialization is exclusively available for MacRuby.

Author: Overbryd

lib/multi_json.rb

@@ -55,6 +55,7 @@ def default_engine
   # * <tt>:json_pure</tt>
   # * <tt>:ok_json</tt>
   # * <tt>:yajl</tt>
+  # * <tt>:nsjsonserialization</tt> (MacRuby only)
   def engine=(new_engine)
     case new_engine
     when String, Symbol

lib/multi_json/engines/nsjsonserialization.rb

@@ -0,0 +1,33 @@
+require 'multi_json/engines/ok_json'
+
+module MultiJson
+  module Engines
+    class Nsjsonserialization < MultiJson::Engines::OkJson
+      ParseError = ::MultiJson::OkJson::Error
+      
+      def self.decode(string, options = {})
+        string = string.read if string.respond_to?(:read)
+        data = string.dataUsingEncoding(NSUTF8StringEncoding)
+        object = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingMutableContainers, error: nil)
+        if object
+          object = symbolize_keys(object) if options[:symbolize_keys]
+          object
+        else
+          super(string, options = {})
+        end
+      end
+
+      def self.encode(object, options = {})
+        pretty = options[:pretty] ? NSJSONWritingPrettyPrinted : 0
+        object = object.as_json if object.respond_to?(:as_json)
+        if NSJSONSerialization.isValidJSONObject(object)
+          data = NSJSONSerialization.dataWithJSONObject(object, options: pretty, error: nil)
+          NSString.alloc.initWithData(data, encoding: NSUTF8StringEncoding)
+        else
+          super(object, options)
+        end
+      end
+      
+    end
+  end
+end

spec/helper.rb

@@ -1,5 +1,13 @@
+def macruby?
+  defined?(RUBY_ENGINE) && RUBY_ENGINE == 'macruby'
+end
+
+if macruby?
+  framework 'Cocoa'
+end
+
 require 'simplecov'
-SimpleCov.start
+SimpleCov.start unless macruby?
 require 'multi_json'
 require 'rspec'
 
@@ -23,6 +31,10 @@ def yajl_on_travis(engine)
   ENV['TRAVIS'] && engine == 'yajl' && jruby?
 end
 
+def nsjsonserialization_on_other_than_macruby(engine)
+  engine == 'nsjsonserialization' && !macruby?
+end
+
 def jruby?
   defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby'
 end

spec/multi_json_spec.rb

@@ -57,11 +57,15 @@
     end
   end
 
-  %w(json_gem json_pure ok_json yajl).each do |engine|
+  %w(json_gem json_pure ok_json yajl nsjsonserialization).each do |engine|
     if yajl_on_travis(engine)
       puts "Yajl with JRuby is not tested on Travis as C-exts are turned off due to there experimental nature"
       next
     end
+    if nsjsonserialization_on_other_than_macruby(engine)
+      puts "NSJSONSerialization is exclusively available for MacRuby only."
+      next
+    end
 
     context engine do
       before do