12 files changed, 215 insertions, 18 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 983e7d0dac..8d3b136d80 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,15 @@
 *Edge*
 
+* Add Array#in_groups which splits or iterates over the array in specified number of groups. #579. [Adrian Mugnolo] Example:
+  
+  a = (1..10).to_a
+  a.in_groups(3)        #=> [[1, 2, 3, 4], [5, 6, 7, nil], [8, 9, 10, nil]]
+  a.in_groups(3, false) #=> [[1, 2, 3, 4], [5, 6, 7], [8, 9, 10]]
+
+* Fix TimeWithZone unmarshaling: coerce unmarshaled Time instances to utc, because Ruby's marshaling of Time instances doesn't respect the zone [Geoff Buesing]
+
+* Added Memoizable mixin for caching simple lazy loaded attributes [Josh Peek]
+
 * Move the test related core_ext stuff out of core_ext so it's only loaded by the test helpers.  [Michael Koziarski]
 
 * Add Inflection rules for String#humanize. #535 [dcmanges]
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index 1a8603e892..0526057b15 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -43,6 +43,7 @@ require 'active_support/ordered_hash'
 require 'active_support/ordered_options'
 require 'active_support/option_merger'
 
+require 'active_support/memoizable'
 require 'active_support/string_inquirer'
 
 require 'active_support/values/time_zone'
diff --git a/activesupport/lib/active_support/core_ext/array/grouping.rb b/activesupport/lib/active_support/core_ext/array/grouping.rb
index 767acc4e07..df37afb053 100644
--- a/activesupport/lib/active_support/core_ext/array/grouping.rb
+++ b/activesupport/lib/active_support/core_ext/array/grouping.rb
@@ -4,8 +4,8 @@ module ActiveSupport #:nodoc:
   module CoreExtensions #:nodoc:
     module Array #:nodoc:
       module Grouping
-        # Iterates over the array in groups of size +number+, padding any remaining 
-        # slots with +fill_with+ unless it is +false+.
+        # Splits or iterates over the array in groups of size +number+,
+        # padding any remaining slots with +fill_with+ unless it is +false+.
         # 
         #   %w(1 2 3 4 5 6 7).in_groups_of(3) {|g| p g}
         #   ["1", "2", "3"]
@@ -39,6 +39,49 @@ module ActiveSupport #:nodoc:
           end
         end
 
+        # Splits or iterates over the array in +number+ of groups, padding any
+        # remaining slots with +fill_with+ unless it is +false+.
+        #
+        #   %w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|g| p g}
+        #   ["1", "2", "3", "4"]
+        #   ["5", "6", "7", nil]
+        #   ["8", "9", "10", nil]
+        #
+        #   %w(1 2 3 4 5 6 7).in_groups(3, ' ') {|g| p g}
+        #   ["1", "2", "3"]
+        #   ["4", "5", " "]
+        #   ["6", "7", " "]
+        #
+        #   %w(1 2 3 4 5 6 7).in_groups(3, false) {|g| p g}
+        #   ["1", "2", "3"]
+        #   ["4", "5"]
+        #   ["6", "7"]
+        def in_groups(number, fill_with = nil)
+          # size / number gives minor group size;
+          # size % number gives how many objects need extra accomodation;
+          # each group hold either division or division + 1 items.
+          division = size / number
+          modulo = size % number
+
+          # create a new array avoiding dup
+          groups = []
+          start = 0
+
+          number.times do |index|
+            length = division + (modulo > 0 && modulo > index ? 1 : 0)
+            padding = fill_with != false &&
+              modulo > 0 && length == division ? 1 : 0
+            groups << slice(start, length).concat([fill_with] * padding)
+            start += length
+          end
+
+          if block_given?
+            groups.each{|g| yield(g) }
+          else
+            groups
+          end
+        end
+
         # Divides the array into one or more subarrays based on a delimiting +value+
         # or the result of an optional block.
         #
diff --git a/activesupport/lib/active_support/core_ext/module/introspection.rb b/activesupport/lib/active_support/core_ext/module/introspection.rb
index 40bbebb7c4..45f3e4bf5c 100644
--- a/activesupport/lib/active_support/core_ext/module/introspection.rb
+++ b/activesupport/lib/active_support/core_ext/module/introspection.rb
@@ -1,4 +1,14 @@
 class Module
+  # Returns the name of the module containing this one.
+  #
+  #   p M::N.parent_name # => "M"
+  def parent_name
+    unless defined? @parent_name
+      @parent_name = name =~ /::[^:]+\Z/ ? $`.freeze : nil
+    end
+    @parent_name
+  end
+
   # Returns the module which contains this one according to its name.
   #
   #   module M
@@ -16,8 +26,7 @@ class Module
   #   p Module.new.parent # => Object
   #
   def parent
-    parent_name = name.split('::')[0..-2] * '::'
-    parent_name.empty? ? Object : parent_name.constantize
+    parent_name ? parent_name.constantize : Object
   end
 
   # Returns all the parents of this module according to its name, ordered from
@@ -35,10 +44,12 @@ class Module
   #
   def parents
     parents = []
-    parts = name.split('::')[0..-2]
-    until parts.empty?
-      parents << (parts * '::').constantize
-      parts.pop
+    if parent_name
+      parts = parent_name.split('::')
+      until parts.empty?
+        parents << (parts * '::').constantize
+        parts.pop
+      end
     end
     parents << Object unless parents.include? Object
     parents
@@ -70,6 +81,6 @@ class Module
   # Returns the names of the constants defined locally rather than the
   # constants themselves. See <tt>local_constants</tt>.
   def local_constant_names
-    local_constants.map(&:to_s)
+    local_constants.map { |c| c.to_s }
   end
 end
diff --git a/activesupport/lib/active_support/core_ext/object/instance_variables.rb b/activesupport/lib/active_support/core_ext/object/instance_variables.rb
index 9f1d4ed2aa..4ecaab3bbb 100644
--- a/activesupport/lib/active_support/core_ext/object/instance_variables.rb
+++ b/activesupport/lib/active_support/core_ext/object/instance_variables.rb
@@ -35,7 +35,7 @@ class Object
   #   C.new(0, 1).instance_variable_names # => ["@y", "@x"]
   if RUBY_VERSION >= '1.9'
     def instance_variable_names
-      instance_variables.map(&:to_s)
+      instance_variables.map { |var| var.to_s }
     end
   else
     alias_method :instance_variable_names, :instance_variables
diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
index d3d9ff9de4..2f3fa72bb4 100644
--- a/activesupport/lib/active_support/dependencies.rb
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -387,7 +387,7 @@ module ActiveSupport #:nodoc:
     ensure
       # Remove the stack frames that we added.
       if defined?(watch_frames) && ! watch_frames.blank?
-        frame_ids = watch_frames.collect(&:object_id)
+        frame_ids = watch_frames.collect { |frame| frame.object_id }
         constant_watch_stack.delete_if do |watch_frame|
           frame_ids.include? watch_frame.object_id
         end
@@ -437,7 +437,7 @@ module ActiveSupport #:nodoc:
     protected
       def log_call(*args)
         if defined?(RAILS_DEFAULT_LOGGER) && RAILS_DEFAULT_LOGGER && log_activity
-          arg_str = args.collect(&:inspect) * ', '
+          arg_str = args.collect { |arg| arg.inspect } * ', '
           /in `([a-z_\?\!]+)'/ =~ caller(1).first
           selector = $1 || '<unknown>'
           log "called #{selector}(#{arg_str})"
diff --git a/activesupport/lib/active_support/json/encoders/date_time.rb b/activesupport/lib/active_support/json/encoders/date_time.rb
index d41c3e9786..a4a5efbfb1 100644
--- a/activesupport/lib/active_support/json/encoders/date_time.rb
+++ b/activesupport/lib/active_support/json/encoders/date_time.rb
@@ -8,7 +8,7 @@ class DateTime
     if ActiveSupport.use_standard_json_time_format
       xmlschema.inspect
     else
-      %("#{strftime("%Y/%m/%d %H:%M:%S %z")}")
+      strftime('"%Y/%m/%d %H:%M:%S %z"')
     end
   end
 end
diff --git a/activesupport/lib/active_support/memoizable.rb b/activesupport/lib/active_support/memoizable.rb
new file mode 100644
index 0000000000..d06250171a
--- /dev/null
+++ b/activesupport/lib/active_support/memoizable.rb
@@ -0,0 +1,35 @@
+module ActiveSupport
+  module Memoizable
+    def self.included(base) #:nodoc:
+      base.extend(ClassMethods)
+    end
+
+    module ClassMethods
+      def memoize(symbol)
+        original_method = "_unmemoized_#{symbol}"
+        memoized_ivar = "@_memoized_#{symbol}"
+        raise "Already memoized #{symbol}" if instance_methods.map(&:to_s).include?(original_method)
+
+        alias_method original_method, symbol
+        class_eval <<-EOS, __FILE__, __LINE__
+          def #{symbol}
+            if defined? #{memoized_ivar}
+              #{memoized_ivar}
+            else
+              #{memoized_ivar} = #{original_method}
+            end
+          end
+        EOS
+      end
+    end
+
+    def freeze
+      methods.each do |method|
+        if m = method.to_s.match(/\A_unmemoized_(.*)/)
+          send(m[1]).freeze
+        end
+      end
+      super
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index 88593eb92d..e85bfe9b2e 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -263,7 +263,7 @@ module ActiveSupport
     end
     
     def marshal_load(variables)
-      initialize(variables[0], ::Time.send!(:get_zone, variables[1]), variables[2])
+      initialize(variables[0].utc, ::Time.send!(:get_zone, variables[1]), variables[2].utc)
     end
 
     # Ensure proxy class responds to all methods that underlying time instance responds to.
diff --git a/activesupport/test/core_ext/array_ext_test.rb b/activesupport/test/core_ext/array_ext_test.rb
index 7563be44f8..62a1f61d53 100644
--- a/activesupport/test/core_ext/array_ext_test.rb
+++ b/activesupport/test/core_ext/array_ext_test.rb
@@ -99,7 +99,7 @@ class ArrayExtToSTests < Test::Unit::TestCase
 end
 
 class ArrayExtGroupingTests < Test::Unit::TestCase
-  def test_group_by_with_perfect_fit
+  def test_in_groups_of_with_perfect_fit
     groups = []
     ('a'..'i').to_a.in_groups_of(3) do |group|
       groups << group
@@ -109,7 +109,7 @@ class ArrayExtGroupingTests < Test::Unit::TestCase
     assert_equal [%w(a b c), %w(d e f), %w(g h i)], ('a'..'i').to_a.in_groups_of(3)
   end
 
-  def test_group_by_with_padding
+  def test_in_groups_of_with_padding
     groups = []
     ('a'..'g').to_a.in_groups_of(3) do |group|
       groups << group
@@ -118,7 +118,7 @@ class ArrayExtGroupingTests < Test::Unit::TestCase
     assert_equal [%w(a b c), %w(d e f), ['g', nil, nil]], groups
   end
 
-  def test_group_by_pads_with_specified_values
+  def test_in_groups_of_pads_with_specified_values
     groups = []
 
     ('a'..'g').to_a.in_groups_of(3, 'foo') do |group|
@@ -128,7 +128,7 @@ class ArrayExtGroupingTests < Test::Unit::TestCase
     assert_equal [%w(a b c), %w(d e f), ['g', 'foo', 'foo']], groups
   end
 
-  def test_group_without_padding
+  def test_in_groups_of_without_padding
     groups = []
 
     ('a'..'g').to_a.in_groups_of(3, false) do |group|
@@ -137,6 +137,48 @@ class ArrayExtGroupingTests < Test::Unit::TestCase
 
     assert_equal [%w(a b c), %w(d e f), ['g']], groups
   end
+
+  def test_in_groups_returned_array_size
+    array = (1..7).to_a
+
+    1.upto(array.size + 1) do |number|
+      assert_equal number, array.in_groups(number).size
+    end
+  end
+
+  def test_in_groups_with_empty_array
+    assert_equal [[], [], []], [].in_groups(3)
+  end
+
+  def test_in_groups_with_block
+    array = (1..9).to_a
+    groups = []
+
+    array.in_groups(3) do |group|
+      groups << group
+    end
+
+    assert_equal array.in_groups(3), groups
+  end
+
+  def test_in_groups_with_perfect_fit
+    assert_equal [[1, 2, 3], [4, 5, 6], [7, 8, 9]],
+      (1..9).to_a.in_groups(3)
+  end
+
+  def test_in_groups_with_padding
+    array = (1..7).to_a
+
+    assert_equal [[1, 2, 3], [4, 5, nil], [6, 7, nil]],
+      array.in_groups(3)
+    assert_equal [[1, 2, 3], [4, 5, 'foo'], [6, 7, 'foo']],
+      array.in_groups(3, 'foo')
+  end
+
+  def test_in_groups_without_padding
+    assert_equal [[1, 2, 3], [4, 5], [6, 7]],
+      (1..7).to_a.in_groups(3, false)
+  end
 end
 
 class ArraySplitTests < Test::Unit::TestCase
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index ac52a1be0b..dfe04485be 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -320,8 +320,11 @@ class TimeWithZoneTest < Test::Unit::TestCase
       marshal_str = Marshal.dump(@twz)
       mtime = Marshal.load(marshal_str)
       assert_equal Time.utc(2000, 1, 1, 0), mtime.utc
+      assert mtime.utc.utc?
       assert_equal ActiveSupport::TimeZone['Eastern Time (US & Canada)'], mtime.time_zone
       assert_equal Time.utc(1999, 12, 31, 19), mtime.time
+      assert mtime.time.utc?
+      assert_equal @twz.inspect, mtime.inspect
     end
   end
 
@@ -331,8 +334,11 @@ class TimeWithZoneTest < Test::Unit::TestCase
       marshal_str = Marshal.dump(twz)
       mtime = Marshal.load(marshal_str)
       assert_equal Time.utc(2000, 1, 1, 0), mtime.utc
+      assert mtime.utc.utc?
       assert_equal 'America/New_York', mtime.time_zone.name
       assert_equal Time.utc(1999, 12, 31, 19), mtime.time
+      assert mtime.time.utc?
+      assert_equal @twz.inspect, mtime.inspect
     end
   end
 
diff --git a/activesupport/test/memoizable_test.rb b/activesupport/test/memoizable_test.rb
new file mode 100644
index 0000000000..fc24a2942d
--- /dev/null
+++ b/activesupport/test/memoizable_test.rb
@@ -0,0 +1,49 @@
+require 'abstract_unit'
+
+uses_mocha 'Memoizable' do
+  class MemoizableTest < Test::Unit::TestCase
+    class Person
+      include ActiveSupport::Memoizable
+
+      def name
+        fetch_name_from_floppy
+      end
+      memoize :name
+
+      def age
+        nil
+      end
+      memoize :age
+
+      private
+        def fetch_name_from_floppy
+          "Josh"
+        end
+    end
+
+    def test_memoization
+      person = Person.new
+      assert_equal "Josh", person.name
+
+      person.expects(:fetch_name_from_floppy).never
+      2.times { assert_equal "Josh", person.name }
+    end
+
+    def test_memoized_methods_are_frozen
+      person = Person.new
+      person.freeze
+      assert_equal "Josh", person.name
+      assert_equal true, person.name.frozen?
+    end
+
+    def test_memoization_frozen_with_nil_value
+      person = Person.new
+      person.freeze
+      assert_equal nil, person.age
+    end
+
+    def test_double_memoization
+      assert_raise(RuntimeError) { Person.memoize :name }
+    end
+  end
+end