Improve performance of ActiveSupport::JSON.encode

activemodel/test/cases/serializers/json_serialization_test.rb

@@ -179,7 +179,7 @@ def @contact.favorite_quote; "Constraints are liberating"; end
   end
 
   test "custom as_json should be honored when generating json" do
-    def @contact.as_json(options); { name: name, created_at: created_at }; end
+    def @contact.as_json(options = nil); { name: name, created_at: created_at }; end
     json = @contact.to_json
 
     assert_match %r{"name":"Konata Izumi"}, json

activerecord/test/cases/json_serialization_test.rb

@@ -149,8 +149,8 @@ def test_serializable_hash_with_default_except_option_and_excluding_inheritance_
     @contact = ContactSti.new(@contact.attributes)
     assert_equal "ContactSti", @contact.type
 
-    def @contact.serializable_hash(options = {})
-      super({ except: %w(age) }.merge!(options))
+    def @contact.serializable_hash(options = nil)
+      super({ except: %w(age) }.merge!(options || {}))
     end
 
     json = @contact.to_json

activesupport/lib/active_support/json/encoding.rb

@@ -35,7 +35,16 @@ def initialize(options = nil)
 
         # Encode the given object into a JSON string
         def encode(value)
-          stringify jsonify value.as_json(options.dup)
+          unless options.empty?
+            value = value.as_json(options.dup)
+          end
+          json = stringify(jsonify(value))
+          if Encoding.escape_html_entities_in_json
+            json.gsub! ESCAPE_REGEX_WITH_HTML_ENTITIES, ESCAPED_CHARS
+          else
+            json.gsub! ESCAPE_REGEX_WITHOUT_HTML_ENTITIES, ESCAPED_CHARS
+          end
+          json
         end
 
         private
@@ -53,31 +62,12 @@ def encode(value)
           ESCAPE_REGEX_WITH_HTML_ENTITIES = /[\u2028\u2029><&]/u
           ESCAPE_REGEX_WITHOUT_HTML_ENTITIES = /[\u2028\u2029]/u
 
-          # This class wraps all the strings we see and does the extra escaping
-          class EscapedString < String # :nodoc:
-            def to_json(*)
-              if Encoding.escape_html_entities_in_json
-                s = super
-                s.gsub! ESCAPE_REGEX_WITH_HTML_ENTITIES, ESCAPED_CHARS
-                s
-              else
-                s = super
-                s.gsub! ESCAPE_REGEX_WITHOUT_HTML_ENTITIES, ESCAPED_CHARS
-                s
-              end
-            end
-
-            def to_s
-              self
-            end
-          end
-
           # Mark these as private so we don't leak encoding-specific constructs
           private_constant :ESCAPED_CHARS, :ESCAPE_REGEX_WITH_HTML_ENTITIES,
-            :ESCAPE_REGEX_WITHOUT_HTML_ENTITIES, :EscapedString
+            :ESCAPE_REGEX_WITHOUT_HTML_ENTITIES
 
           # Convert an object into a "JSON-ready" representation composed of
-          # primitives like Hash, Array, String, Numeric,
+          # primitives like Hash, Array, String, Symbol, Numeric,
           # and +true+/+false+/+nil+.
           # Recursively calls #as_json to the object to recursively build a
           # fully JSON-ready object.
@@ -91,14 +81,15 @@ def to_s
           # calls.
           def jsonify(value)
             case value
-            when String
-              EscapedString.new(value)
-            when Numeric, NilClass, TrueClass, FalseClass
+            when String, Integer, Symbol, nil, true, false
+              value
+            when Numeric
               value.as_json
             when Hash
               result = {}
               value.each do |k, v|
-                result[jsonify(k)] = jsonify(v)
+                k = k.to_s unless Symbol === k || String === k
+                result[k] = jsonify(v)
               end
               result
             when Array

activesupport/test/json/encoding_test_cases.rb

@@ -36,6 +36,26 @@ def initialize(*)
     end
   end
 
+  class RomanNumeral < Numeric
+    def initialize(str)
+      @str = str
+    end
+
+    def as_json(options = nil)
+      @str
+    end
+  end
+
+  class CustomNumeric < Numeric
+    def initialize(str)
+      @str = str
+    end
+
+    def to_json(options = nil)
+      @str
+    end
+  end
+
   module EncodingTestCases
     TrueTests     = [[ true,  %(true)  ]]
     FalseTests    = [[ false, %(false) ]]
@@ -46,7 +66,10 @@ module EncodingTestCases
                      [ 1.0 / 0.0,   %(null) ],
                      [ -1.0 / 0.0,  %(null) ],
                      [ BigDecimal("0.0") / BigDecimal("0.0"),  %(null) ],
-                     [ BigDecimal("2.5"), %("#{BigDecimal('2.5')}") ]]
+                     [ BigDecimal("2.5"), %("#{BigDecimal('2.5')}") ],
+                     [ RomanNumeral.new("MCCCXXXVII"), %("MCCCXXXVII") ],
+                     [ [CustomNumeric.new("123")], %([123]) ]
+    ]
 
     StringTests   = [[ "this is the <string>",     %("this is the \\u003cstring\\u003e")],
                      [ 'a "string" with quotes & an ampersand', %("a \\"string\\" with quotes \\u0026 an ampersand") ],