1 files changed, 92 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
new file mode 100644
index 0000000000..b1dfbde86e
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Array < Type::Value # :nodoc:
+          include ActiveModel::Type::Helpers::Mutable
+
+          Data = Struct.new(:encoder, :values) # :nodoc:
+
+          attr_reader :subtype, :delimiter
+          delegate :type, :user_input_in_time_zone, :limit, :precision, :scale, to: :subtype
+
+          def initialize(subtype, delimiter = ",")
+            @subtype = subtype
+            @delimiter = delimiter
+
+            @pg_encoder = PG::TextEncoder::Array.new name: "#{type}[]", delimiter: delimiter
+            @pg_decoder = PG::TextDecoder::Array.new name: "#{type}[]", delimiter: delimiter
+          end
+
+          def deserialize(value)
+            case value
+            when ::String
+              type_cast_array(@pg_decoder.decode(value), :deserialize)
+            when Data
+              type_cast_array(value.values, :deserialize)
+            else
+              super
+            end
+          end
+
+          def cast(value)
+            if value.is_a?(::String)
+              value = begin
+                @pg_decoder.decode(value)
+              rescue TypeError
+                # malformed array string is treated as [], will raise in PG 2.0 gem
+                # this keeps a consistent implementation
+                []
+              end
+            end
+            type_cast_array(value, :cast)
+          end
+
+          def serialize(value)
+            if value.is_a?(::Array)
+              casted_values = type_cast_array(value, :serialize)
+              Data.new(@pg_encoder, casted_values)
+            else
+              super
+            end
+          end
+
+          def ==(other)
+            other.is_a?(Array) &&
+              subtype == other.subtype &&
+              delimiter == other.delimiter
+          end
+
+          def type_cast_for_schema(value)
+            return super unless value.is_a?(::Array)
+            "[" + value.map { |v| subtype.type_cast_for_schema(v) }.join(", ") + "]"
+          end
+
+          def map(value, &block)
+            value.map(&block)
+          end
+
+          def changed_in_place?(raw_old_value, new_value)
+            deserialize(raw_old_value) != new_value
+          end
+
+          def force_equality?(value)
+            value.is_a?(::Array)
+          end
+
+          private
+
+            def type_cast_array(value, method)
+              if value.is_a?(::Array)
+                value.map { |item| type_cast_array(item, method) }
+              else
+                @subtype.public_send(method, value)
+              end
+            end
+        end
+      end
+    end
+  end
+end