Move non-type objects into the `Type::Helpers` namespace

The type code is actually quite accessible, and I'm planning to
encourage people to look at the files in the `type` folder to learn more
about how it works. This will help reduce the noise from code that is
less about type casting, and more about random AR nonsense.

4 files changed, 97 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/type/helpers/accepts_multiparameter_time.rb b/activerecord/lib/active_record/type/helpers/accepts_multiparameter_time.rb
index c528d410d3..640943c5e9 100644
--- a/activerecord/lib/active_record/type/helpers/accepts_multiparameter_time.rb
+++ b/activerecord/lib/active_record/type/helpers/accepts_multiparameter_time.rb
@@ -1,7 +1,7 @@
 module ActiveRecord
   module Type
     module Helpers
-      class AcceptsMultiparameterTime < Module
+      class AcceptsMultiparameterTime < Module # :nodoc:
         def initialize(defaults: {})
           define_method(:type_cast_from_user) do |value|
             if value.is_a?(Hash)
diff --git a/activerecord/lib/active_record/type/helpers/mutable.rb b/activerecord/lib/active_record/type/helpers/mutable.rb
new file mode 100644
index 0000000000..dc37f4a885
--- /dev/null
+++ b/activerecord/lib/active_record/type/helpers/mutable.rb
@@ -0,0 +1,18 @@
+module ActiveRecord
+  module Type
+    module Helpers
+      module Mutable # :nodoc:
+        def type_cast_from_user(value)
+          type_cast_from_database(type_cast_for_database(value))
+        end
+
+        # +raw_old_value+ will be the `_before_type_cast` version of the
+        # value (likely a string). +new_value+ will be the current, type
+        # cast value.
+        def changed_in_place?(raw_old_value, new_value)
+          raw_old_value != type_cast_for_database(new_value)
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/helpers/numeric.rb b/activerecord/lib/active_record/type/helpers/numeric.rb
new file mode 100644
index 0000000000..86888eef75
--- /dev/null
+++ b/activerecord/lib/active_record/type/helpers/numeric.rb
@@ -0,0 +1,38 @@
+module ActiveRecord
+  module Type
+    module Helpers
+      module Numeric # :nodoc:
+        def number?
+          true
+        end
+
+        def type_cast(value)
+          value = case value
+                  when true then 1
+                  when false then 0
+                  when ::String then value.presence
+                  else value
+                  end
+          super(value)
+        end
+
+        def changed?(old_value, _new_value, new_value_before_type_cast) # :nodoc:
+          super || number_to_non_number?(old_value, new_value_before_type_cast)
+        end
+
+        private
+
+        def number_to_non_number?(old_value, new_value_before_type_cast)
+          old_value != nil && non_numeric_string?(new_value_before_type_cast)
+        end
+
+        def non_numeric_string?(value)
+          # 'wibble'.to_i will give zero, we want to make sure
+          # that we aren't marking int zero to string zero as
+          # changed.
+          value.to_s !~ /\A-?\d+\.?\d*\z/
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/type/helpers/time_value.rb b/activerecord/lib/active_record/type/helpers/time_value.rb
new file mode 100644
index 0000000000..6e14c3a9b5
--- /dev/null
+++ b/activerecord/lib/active_record/type/helpers/time_value.rb
@@ -0,0 +1,40 @@
+module ActiveRecord
+  module Type
+    module Helpers
+      module TimeValue # :nodoc:
+        def type_cast_for_schema(value)
+          "'#{value.to_s(:db)}'"
+        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
+            Base.default_timezone == :utc ? time : time.getlocal
+          else
+            ::Time.public_send(Base.default_timezone, year, mon, mday, hour, min, sec, microsec) rescue nil
+          end
+        end
+
+        # Doesn't handle time zones.
+        def fast_string_to_time(string)
+          if string =~ ConnectionAdapters::Column::Format::ISO_DATETIME
+            microsec = ($7.to_r * 1_000_000).to_i
+            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