1 files changed, 62 insertions, 13 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
index 4e7d472d97..c203e6c604 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -2,12 +2,27 @@ module ActiveRecord
   module ConnectionAdapters
     module PostgreSQL
       module OID # :nodoc:
-        class Array < Type::Value
-          attr_reader :subtype
+        class Array < Type::Value # :nodoc:
+          include Type::Mutable
+
+          # Loads pg_array_parser if available. String parsing can be
+          # performed quicker by a native extension, which will not create
+          # a large amount of Ruby objects that will need to be garbage
+          # collected. pg_array_parser has a C and Java extension
+          begin
+            require 'pg_array_parser'
+            include PgArrayParser
+          rescue LoadError
+            require 'active_record/connection_adapters/postgresql/array_parser'
+            include PostgreSQL::ArrayParser
+          end
+
+          attr_reader :subtype, :delimiter
           delegate :type, to: :subtype
 
-          def initialize(subtype)
+          def initialize(subtype, delimiter = ',')
             @subtype = subtype
+            @delimiter = delimiter
           end
 
           def type_cast_from_database(value)
@@ -19,19 +34,18 @@ module ActiveRecord
           end
 
           def type_cast_from_user(value)
+            if value.is_a?(::String)
+              value = parse_pg_array(value)
+            end
             type_cast_array(value, :type_cast_from_user)
           end
 
-          # Loads pg_array_parser if available. String parsing can be
-          # performed quicker by a native extension, which will not create
-          # a large amount of Ruby objects that will need to be garbage
-          # collected. pg_array_parser has a C and Java extension
-          begin
-            require 'pg_array_parser'
-            include PgArrayParser
-          rescue LoadError
-            require 'active_record/connection_adapters/postgresql/array_parser'
-            include PostgreSQL::ArrayParser
+          def type_cast_for_database(value)
+            if value.is_a?(::Array)
+              cast_value_for_database(value)
+            else
+              super
+            end
           end
 
           private
@@ -43,6 +57,41 @@ module ActiveRecord
               @subtype.public_send(method, value)
             end
           end
+
+          def cast_value_for_database(value)
+            if value.is_a?(::Array)
+              casted_values = value.map { |item| cast_value_for_database(item) }
+              "{#{casted_values.join(delimiter)}}"
+            else
+              quote_and_escape(subtype.type_cast_for_database(value))
+            end
+          end
+
+          ARRAY_ESCAPE = "\\" * 2 * 2 # escape the backslash twice for PG arrays
+
+          def quote_and_escape(value)
+            case value
+            when ::String
+              if string_requires_quoting?(value)
+                value = value.gsub(/\\/, ARRAY_ESCAPE)
+                value.gsub!(/"/,"\\\"")
+                %("#{value}")
+              else
+                value
+              end
+            when nil then "NULL"
+            else value
+            end
+          end
+
+          # See http://www.postgresql.org/docs/9.2/static/arrays.html#ARRAYS-IO
+          # for a list of all cases in which strings will be quoted.
+          def string_requires_quoting?(string)
+            string.empty? ||
+              string == "NULL" ||
+              string =~ /[\{\}"\\\s]/ ||
+              string.include?(delimiter)
+          end
         end
       end
     end