Adding Time and DateTime #compare_with_coercion, which layers behavior on #<=>...

Adding Time and DateTime #compare_with_coercion, which layers behavior on #<=> so that any combination of Time, DateTime and ActiveSupport::TimeWithZone instances can be chronologically compared

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8711 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

 *SVN*
 
+* Adding Time and DateTime #compare_with_coercion, which layers behavior on #<=> so that any combination of Time, DateTime and ActiveSupport::TimeWithZone instances can be chronologically compared [Geoff Buesing]
+
 * TimeZone#now returns an ActiveSupport::TimeWithZone [Geoff Buesing]
 
 * Time #in_current_time_zone and #change_time_zone_to_current return self when Time.zone is nil [Geoff Buesing]

activesupport/lib/active_support/core_ext/date_time/calculations.rb

@@ -7,6 +7,11 @@ module DateTime #:nodoc:
       module Calculations
         def self.included(base) #:nodoc:
           base.extend ClassMethods
+          
+          base.class_eval do
+            alias_method :compare_without_coercion, :<=>
+            alias_method :<=>, :compare_with_coercion
+          end
         end
 
         module ClassMethods
@@ -91,6 +96,13 @@ def utc?
         def utc_offset
           (offset * 86400).to_i
         end
+        
+        # Layers additional behavior on DateTime#<=> so that Time and ActiveSupport::TimeWithZone instances can be compared with a DateTime
+        def compare_with_coercion(other)
+          other = other.comparable_time if other.respond_to?(:comparable_time)
+          other = other.to_datetime unless other.acts_like?(:date)
+          compare_without_coercion(other)
+        end
       end
     end
   end

activesupport/lib/active_support/core_ext/time/calculations.rb

@@ -9,8 +9,12 @@ def self.included(base) #:nodoc:
           base.class_eval do
             alias_method :plus_without_duration, :+
             alias_method :+, :plus_with_duration
+            
             alias_method :minus_without_duration, :-
             alias_method :-, :minus_with_duration
+            
+            alias_method :compare_without_coercion, :<=>
+            alias_method :<=>, :compare_with_coercion
           end
         end
 
@@ -218,6 +222,19 @@ def minus_with_duration(other) #:nodoc:
             minus_without_duration(other)
           end
         end
+        
+        # Layers additional behavior on Time#<=> so that DateTime and ActiveSupport::TimeWithZone instances
+        # can be chronologically compared with a Time
+        def compare_with_coercion(other)
+          # if other is an ActiveSupport::TimeWithZone, coerce a Time instance from it so we can do <=> comparision
+          other = other.comparable_time if other.respond_to?(:comparable_time)
+          if other.acts_like?(:date)
+            # other is a Date/DateTime, so coerce self #to_datetime and hand off to DateTime#<=>
+            to_datetime.compare_without_coercion(other)
+          else
+            compare_without_coercion(other)
+          end
+        end
       end
     end
   end

activesupport/lib/active_support/time_with_zone.rb

@@ -105,7 +105,6 @@ def strftime(format)
   
     # Use the time in UTC for comparisons
     def <=>(other)
-      other = other.comparable_time if other.respond_to?(:comparable_time) # to coerce time from TimeWithZone
       utc <=> other
     end
   

activesupport/test/core_ext/date_time_ext_test.rb

@@ -253,6 +253,24 @@ def test_formatted_offset_with_local
     assert_equal '-05:00', dt.formatted_offset
     assert_equal '-0500', dt.formatted_offset(false)
   end
+  
+  def test_compare_with_time
+    assert_equal  1, DateTime.civil(2000) <=> Time.utc(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, DateTime.civil(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, DateTime.civil(2000) <=> Time.utc(2000, 1, 1, 0, 0, 1))
+  end
+  
+  def test_compare_with_datetime
+    assert_equal  1, DateTime.civil(2000) <=> DateTime.civil(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, DateTime.civil(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, DateTime.civil(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 1))
+  end
+  
+  def test_compare_with_time_with_zone
+    assert_equal  1, DateTime.civil(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(1999, 12, 31, 23, 59, 59) )
+    assert_equal  0, DateTime.civil(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 0) )
+    assert_equal(-1, DateTime.civil(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 1) ))
+  end
 
   protected
     def with_timezone(new_tz = 'US/Eastern')

activesupport/test/core_ext/time_ext_test.rb

@@ -424,6 +424,24 @@ def test_formatted_offset_with_local
       assert_equal '-0400', Time.local(2000, 7).formatted_offset(false)
     end
   end
+  
+  def test_compare_with_time
+    assert_equal  1, Time.utc(2000) <=> Time.utc(1999, 12, 31, 23, 59, 59, 999)
+    assert_equal  0, Time.utc(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, Time.utc(2000) <=> Time.utc(2000, 1, 1, 0, 0, 0, 001))
+  end
+  
+  def test_compare_with_datetime
+    assert_equal  1, Time.utc(2000) <=> DateTime.civil(1999, 12, 31, 23, 59, 59)
+    assert_equal  0, Time.utc(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 0)
+    assert_equal(-1, Time.utc(2000) <=> DateTime.civil(2000, 1, 1, 0, 0, 1))
+  end
+  
+  def test_compare_with_time_with_zone
+    assert_equal  1, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(1999, 12, 31, 23, 59, 59) )
+    assert_equal  0, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 0) )
+    assert_equal(-1, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 1) ))
+  end
 
   protected
     def with_timezone(new_tz = 'US/Eastern')

activesupport/test/core_ext/time_with_zone_test.rb

@@ -87,12 +87,24 @@ def test_to_s_db
     def test_xmlschema
       assert_equal "1999-12-31T19:00:00-05:00", @twz.xmlschema
     end
-      
-    def test_compare
+    
+    def test_compare_with_time
       assert_equal  1, @twz <=> Time.utc(1999, 12, 31, 23, 59, 59)
-      assert_equal  0, @twz <=> Time.utc(2000)
+      assert_equal  0, @twz <=> Time.utc(2000, 1, 1, 0, 0, 0)
       assert_equal(-1, @twz <=> Time.utc(2000, 1, 1, 0, 0, 1))
     end
+
+    def test_compare_with_datetime
+      assert_equal  1, @twz <=> DateTime.civil(1999, 12, 31, 23, 59, 59)
+      assert_equal  0, @twz <=> DateTime.civil(2000, 1, 1, 0, 0, 0)
+      assert_equal(-1, @twz <=> DateTime.civil(2000, 1, 1, 0, 0, 1))
+    end
+
+    def test_compare_with_time_with_zone
+      assert_equal  1, @twz <=> ActiveSupport::TimeWithZone.new( Time.utc(1999, 12, 31, 23, 59, 59) )
+      assert_equal  0, @twz <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 0) )
+      assert_equal(-1, @twz <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 1) ))
+    end
       
     def test_plus
       assert_equal Time.utc(1999, 12, 31, 19, 0 ,5), (@twz + 5).time