1 files changed, 86 insertions, 0 deletions
diff --git a/activemodel/lib/active_model/type/helpers/time_value.rb b/activemodel/lib/active_model/type/helpers/time_value.rb
new file mode 100644
index 0000000000..da56073436
--- /dev/null
+++ b/activemodel/lib/active_model/type/helpers/time_value.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/string/zones"
+require "active_support/core_ext/time/zones"
+
+module ActiveModel
+  module Type
+    module Helpers # :nodoc: all
+      module TimeValue
+        def serialize(value)
+          value = apply_seconds_precision(value)
+
+          if value.acts_like?(:time)
+            zone_conversion_method = is_utc? ? :getutc : :getlocal
+
+            if value.respond_to?(zone_conversion_method)
+              value = value.send(zone_conversion_method)
+            end
+          end
+
+          value
+        end
+
+        def is_utc?
+          ::Time.zone_default.nil? || ::Time.zone_default =~ "UTC"
+        end
+
+        def default_timezone
+          if is_utc?
+            :utc
+          else
+            :local
+          end
+        end
+
+        def apply_seconds_precision(value)
+          return value unless precision && value.respond_to?(:usec)
+          number_of_insignificant_digits = 6 - precision
+          round_power = 10**number_of_insignificant_digits
+          value.change(usec: value.usec - value.usec % round_power)
+        end
+
+        def type_cast_for_schema(value)
+          value.to_s(:db).inspect
+        end
+
+        def user_input_in_time_zone(value)
+          value.in_time_zone
+        end
+
+        private
+
+          def new_time(year, mon, mday, hour, min, sec, microsec, offset = nil)
+            # Treat 0000-00-00 00:00:00 as nil.
+            return if year.nil? || (year == 0 && mon == 0 && mday == 0)
+
+            if offset
+              time = ::Time.utc(year, mon, mday, hour, min, sec, microsec) rescue nil
+              return unless time
+
+              time -= offset
+              is_utc? ? time : time.getlocal
+            else
+              ::Time.public_send(default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
+            end
+          end
+
+          ISO_DATETIME = /\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
+
+          # Doesn't handle time zones.
+          def fast_string_to_time(string)
+            if string =~ ISO_DATETIME
+              microsec_part = $7
+              if microsec_part && microsec_part.start_with?(".") && microsec_part.length == 7
+                microsec_part[0] = ""
+                microsec = microsec_part.to_i
+              else
+                microsec = (microsec_part.to_r * 1_000_000).to_i
+              end
+              new_time $1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, microsec
+            end
+          end
+      end
+    end
+  end
+end