1 files changed, 54 insertions, 0 deletions
diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
new file mode 100644
index 0000000000..bafb8e2106
--- /dev/null
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/range"
+
+module ActiveModel
+  module Validations
+    module Clusivity #:nodoc:
+      ERROR_MESSAGE = "An object with the method #include? or a proc, lambda or symbol is required, " \
+                      "and must be supplied as the :in (or :within) option of the configuration hash"
+
+      def check_validity!
+        unless delimiter.respond_to?(:include?) || delimiter.respond_to?(:call) || delimiter.respond_to?(:to_sym)
+          raise ArgumentError, ERROR_MESSAGE
+        end
+      end
+
+    private
+
+      def include?(record, value)
+        members = if delimiter.respond_to?(:call)
+          delimiter.call(record)
+        elsif delimiter.respond_to?(:to_sym)
+          record.send(delimiter)
+        else
+          delimiter
+        end
+
+        members.send(inclusion_method(members), value)
+      end
+
+      def delimiter
+        @delimiter ||= options[:in] || options[:within]
+      end
+
+      # After Ruby 2.2, <tt>Range#include?</tt> on non-number-or-time-ish ranges checks all
+      # possible values in the range for equality, which is slower but more accurate.
+      # <tt>Range#cover?</tt> uses the previous logic of comparing a value with the range
+      # endpoints, which is fast but is only accurate on Numeric, Time, Date,
+      # or DateTime ranges.
+      def inclusion_method(enumerable)
+        if enumerable.is_a? Range
+          case enumerable.first
+          when Numeric, Time, DateTime, Date
+            :cover?
+          else
+            :include?
+          end
+        else
+          :include?
+        end
+      end
+    end
+  end
+end