Cache to_time and to_datetime for performance

As demonstrated in #25880 the to_time method converts the utc time instance to a local time instance which is an expensive operation so since ActiveSupport::TimeWithZone is a value object and shouldn't be mutated we can safely cache it without worrying about invalidation.
rails · Aug 31, 2016 · c2c2f79 · c2c2f79
1 parent 0e6e4a1
commit c2c2f79
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/Gemfile.lock b/Gemfile.lock
@@ -293,3 +293,6 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   w3c_validators
+
+BUNDLED WITH
+   1.12.5
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
@@ -318,11 +318,11 @@ def to_r
 
     # Return an instance of Time in the system timezone.
     def to_time
-      utc.to_time
+      @to_time ||= utc.to_time
     end
 
     def to_datetime
-      utc.to_datetime.new_offset(Rational(utc_offset, 86_400))
+      @to_datetime ||= utc.to_datetime.new_offset(Rational(utc_offset, 86_400))
     end
 
     # So that +self+ <tt>acts_like?(:time)</tt>.