1 files changed, 71 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
new file mode 100644
index 0000000000..7b42677101
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class Hstore < Type::Value # :nodoc:
+          include ActiveModel::Type::Helpers::Mutable
+
+          def type
+            :hstore
+          end
+
+          def deserialize(value)
+            if value.is_a?(::String)
+              ::Hash[value.scan(HstorePair).map { |k, v|
+                v = v.upcase == "NULL" ? nil : v.gsub(/\A"(.*)"\Z/m, '\1').gsub(/\\(.)/, '\1')
+                k = k.gsub(/\A"(.*)"\Z/m, '\1').gsub(/\\(.)/, '\1')
+                [k, v]
+              }]
+            else
+              value
+            end
+          end
+
+          def serialize(value)
+            if value.is_a?(::Hash)
+              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(", ")
+            elsif value.respond_to?(:to_unsafe_h)
+              serialize(value.to_unsafe_h)
+            else
+              value
+            end
+          end
+
+          def accessor
+            ActiveRecord::Store::StringKeyedHashAccessor
+          end
+
+          # Will compare the Hash equivalents of +raw_old_value+ and +new_value+.
+          # By comparing hashes, this avoids an edge case where the order of
+          # the keys change between the two hashes, and they would not be marked
+          # as equal.
+          def changed_in_place?(raw_old_value, new_value)
+            deserialize(raw_old_value) != new_value
+          end
+
+          private
+
+            HstorePair = begin
+              quoted_string = /"[^"\\]*(?:\\.[^"\\]*)*"/
+              unquoted_string = /(?:\\.|[^\s,])[^\s=,\\]*(?:\\.[^\s=,\\]*|=[^,>])*/
+              /(#{quoted_string}|#{unquoted_string})\s*=>\s*(#{quoted_string}|#{unquoted_string})/
+            end
+
+            def escape_hstore(value)
+              if value.nil?
+                "NULL"
+              else
+                if value == ""
+                  '""'
+                else
+                  '"%s"' % value.to_s.gsub(/(["\\])/, '\\\\\1')
+                end
+              end
+            end
+        end
+      end
+    end
+  end
+end