Refactor ActiveSupport::JSON to be less obtuse. Add support for JSON …

…decoding by way of Syck with ActiveSupport::JSON.decode(json_string). Prevent hash keys that are JavaScript reserved words from being unquoted during encoding.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6443 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Refactor ActiveSupport::JSON to be less obtuse.  Add support for JSON decoding by way of Syck with ActiveSupport::JSON.decode(json_string).  Prevent hash keys that are JavaScript reserved words from being unquoted during encoding.  [Sam Stephenson]
+
 * alias_method_chain preserves the original method's visibility.  #7854 [Jonathan Viney]
 
 * Update Dependencies to ignore constants inherited from ancestors. Closes #6951. [Nicholas Seckar]

activesupport/lib/active_support/core_ext/blank.rb

@@ -1,6 +1,6 @@
-class Object #:nodoc:
+class Object 
   # "", "   ", nil, [], and {} are blank
-  def blank?
+  def blank? #:nodoc:
     if respond_to?(:empty?) && respond_to?(:strip)
       empty? or strip.empty?
     elsif respond_to?(:empty?)

activesupport/lib/active_support/core_ext/object/extending.rb

@@ -1,9 +1,9 @@
-class Object #:nodoc:
-  def remove_subclasses_of(*superclasses)
+class Object
+  def remove_subclasses_of(*superclasses) #:nodoc:
     Class.remove_class(*subclasses_of(*superclasses))
   end
 
-  def subclasses_of(*superclasses)
+  def subclasses_of(*superclasses) #:nodoc:
     subclasses = []
     ObjectSpace.each_object(Class) do |k|
       next unless # Exclude this class unless
@@ -16,31 +16,31 @@ def subclasses_of(*superclasses)
     subclasses
   end
 
-  def extended_by
+  def extended_by #:nodoc:
     ancestors = class << self; ancestors end
     ancestors.select { |mod| mod.class == Module } - [ Object, Kernel ]
   end
 
-  def copy_instance_variables_from(object, exclude = [])
+  def copy_instance_variables_from(object, exclude = []) #:nodoc:
     exclude += object.protected_instance_variables if object.respond_to? :protected_instance_variables
 
     instance_variables = object.instance_variables - exclude.map { |name| name.to_s }
     instance_variables.each { |name| instance_variable_set(name, object.instance_variable_get(name)) }
   end
 
-  def extend_with_included_modules_from(object)
+  def extend_with_included_modules_from(object) #:nodoc:
     object.extended_by.each { |mod| extend mod }
   end
 
-  def instance_values
+  def instance_values #:nodoc:
     instance_variables.inject({}) do |values, name|
       values[name[1..-1]] = instance_variable_get(name)
       values
     end
   end
 
   unless defined? instance_exec # 1.9
-    def instance_exec(*arguments, &block)
+    def instance_exec(*arguments, &block) #:nodoc:
       block.bind(self)[*arguments]
     end
   end

activesupport/lib/active_support/core_ext/object/misc.rb

@@ -43,21 +43,12 @@ def with_options(options)
     yield ActiveSupport::OptionMerger.new(self, options)
   end
 
-  # Dumps object in JSON (JavaScript Object Notation).  See www.json.org for more info.
-  #
-  #   Account.find(1).to_json
-  #   => "{attributes: {username: \"foo\", id: \"1\", password: \"bar\"}}"
-  #
-  def to_json
-    ActiveSupport::JSON.encode(self)
-  end
-
   # A duck-type assistant method. For example, ActiveSupport extends Date
   # to define an acts_like_date? method, and extends Time to define
   # acts_like_time?. As a result, we can do "x.acts_like?(:time)" and
   # "x.acts_like?(:date)" to do duck-type-safe comparisons, since classes that
   # we want to act like Time simply need to define an acts_like_time? method.
   def acts_like?(duck)
-    respond_to? :"acts_like_#{duck}?"
+    respond_to? "acts_like_#{duck}?"
   end
 end

activesupport/lib/active_support/dependencies.rb

@@ -480,18 +480,18 @@ def const_missing(class_id)
   end
 end
 
-class Object #:nodoc:
+class Object
 
   alias_method :load_without_new_constant_marking, :load
 
-  def load(file, *extras)
+  def load(file, *extras) #:nodoc:
     Dependencies.new_constants_in(Object) { super(file, *extras) }
   rescue Exception => exception  # errors from loading file
     exception.blame_file! file
     raise
   end
 
-  def require(file, *extras)
+  def require(file, *extras) #:nodoc:
     Dependencies.new_constants_in(Object) { super(file, *extras) }
   rescue Exception => exception  # errors from required file
     exception.blame_file! file

activesupport/lib/active_support/json.rb

@@ -1,48 +1,31 @@
-require 'active_support/json/encoders'
+require 'active_support/json/encoding'
+require 'active_support/json/decoding'
 
 module ActiveSupport
-  module JSON #:nodoc:
-    class CircularReferenceError < StandardError #:nodoc:
-    end
-
-    # A string that returns itself as as its JSON-encoded form.
-    class Variable < String #:nodoc:
-      def to_json
-        self
-      end
-    end
-
-    # When +true+, Hash#to_json will omit quoting string or symbol keys
-    # if the keys are valid JavaScript identifiers.  Note that this is
-    # technically improper JSON (all object keys must be quoted), so if
-    # you need strict JSON compliance, set this option to +false+.
-    mattr_accessor :unquote_hash_key_identifiers
-    @@unquote_hash_key_identifiers = true
+  module JSON
+    RESERVED_WORDS = %w(
+      abstract      delete        goto          private       transient
+      boolean       do            if            protected     try
+      break         double        implements    public        typeof
+      byte          else          import        return        var
+      case          enum          in            short         void
+      catch         export        instanceof    static        volatile
+      char          extends       int           super         while
+      class         final         interface     switch        with
+      const         finally       long          synchronized
+      continue      float         native        this
+      debugger      for           new           throw
+      default       function      package       throws
+    ) #:nodoc:
 
     class << self
-      REFERENCE_STACK_VARIABLE = :json_reference_stack
-
-      def encode(value)
-        raise_on_circular_reference(value) do
-          Encoders[value.class].call(value)
-        end
+      def valid_identifier?(key) #:nodoc:
+        key.to_s =~ /^[[:alpha:]_$][[:alnum:]_$]*$/ && !reserved_word?(key)
       end
-
-      def can_unquote_identifier?(key)
-        return false unless unquote_hash_key_identifiers
-        key.to_s =~ /^[[:alpha:]_$][[:alnum:]_$]*$/
+
+      def reserved_word?(key) #:nodoc:
+        RESERVED_WORDS.include?(key.to_s)
       end
-
-      protected
-        def raise_on_circular_reference(value)
-          stack = Thread.current[REFERENCE_STACK_VARIABLE] ||= []
-          raise CircularReferenceError, 'object references itself' if
-            stack.include? value
-          stack << value
-          yield
-        ensure
-          stack.pop
-        end
     end
   end
 end

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

activesupport/lib/active_support/json/encoders/enumerable.rb

@@ -0,0 +1,5 @@
+module Enumerable
+  def to_json #:nodoc:
+    "[#{map { |value| ActiveSupport::JSON.encode(value) } * ', '}]"
+  end
+end

activesupport/lib/active_support/json/encoders/false_class.rb

@@ -0,0 +1,5 @@
+class FalseClass
+  def to_json #:nodoc:
+    'false'
+  end
+end

activesupport/lib/active_support/json/encoders/hash.rb

@@ -0,0 +1,12 @@
+class Hash
+  def to_json #:nodoc:
+    returning result = '{' do
+      result << map do |key, value|
+        key = ActiveSupport::JSON::Variable.new(key.to_s) if 
+          ActiveSupport::JSON.can_unquote_identifier?(key)
+        "#{ActiveSupport::JSON.encode(key)}: #{ActiveSupport::JSON.encode(value)}"
+      end * ', '
+      result << '}'
+    end
+  end
+end

activesupport/lib/active_support/json/encoders/nil_class.rb

@@ -0,0 +1,5 @@
+class NilClass
+  def to_json #:nodoc:
+    'null'
+  end
+end

activesupport/lib/active_support/json/encoders/numeric.rb

@@ -0,0 +1,5 @@
+class Numeric
+  def to_json #:nodoc:
+    to_s
+  end
+end

activesupport/lib/active_support/json/encoders/object.rb

@@ -0,0 +1,10 @@
+class Object
+  # Dumps object in JSON (JavaScript Object Notation).  See www.json.org for more info.
+  #
+  #   Account.find(1).to_json
+  #   => "{attributes: {username: \"foo\", id: \"1\", password: \"bar\"}}"
+  #
+  def to_json
+    ActiveSupport::JSON.encode(instance_values)
+  end
+end

activesupport/lib/active_support/json/encoders/regexp.rb

@@ -0,0 +1,5 @@
+class Regexp
+  def to_json #:nodoc:
+    inspect
+  end
+end