Merge pull request #7547 from danmcclain/pg-arrays

Adds migration and type casting support for PostgreSQL Array datatype

4 files changed, 163 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
new file mode 100644
index 0000000000..b7d24f2bb3
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
@@ -0,0 +1,97 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLColumn < Column
+      module ArrayParser
+        private
+          # 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
+            def parse_pg_array(string)
+              parse_data(string, 0)
+            end
+          end
+
+          def parse_data(string, index)
+            local_index = index
+            array = []
+            while(local_index < string.length)
+              case string[local_index]
+              when '{'
+                local_index,array = parse_array_contents(array, string, local_index + 1)
+              when '}'
+                return array
+              end
+              local_index += 1
+            end
+
+            array
+          end
+
+          def parse_array_contents(array, string, index)
+            is_escaping = false
+            is_quoted = false
+            was_quoted = false
+            current_item = ''
+
+            local_index = index
+            while local_index
+              token = string[local_index]
+              if is_escaping
+                current_item << token
+                is_escaping = false
+              else
+                if is_quoted
+                  case token
+                  when '"'
+                    is_quoted = false
+                    was_quoted = true
+                  when "\\"
+                    is_escaping = true
+                  else
+                    current_item << token
+                  end
+                else
+                  case token
+                  when "\\"
+                    is_escaping = true
+                  when ','
+                    add_item_to_array(array, current_item, was_quoted)
+                    current_item = ''
+                    was_quoted = false
+                  when '"'
+                    is_quoted = true
+                  when '{'
+                    internal_items = []
+                    local_index,internal_items = parse_array_contents(internal_items, string, local_index + 1)
+                    array.push(internal_items)
+                  when '}'
+                    add_item_to_array(array, current_item, was_quoted)
+                    return local_index,array
+                  else
+                    current_item << token
+                  end
+                end
+              end
+
+              local_index += 1
+            end
+            return local_index,array
+          end
+
+          def add_item_to_array(array, current_item, quoted)
+            if current_item.length == 0
+            elsif !quoted && current_item == 'NULL'
+              array.push nil
+            else
+              array.push current_item
+            end
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb b/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb
index b59195f98a..62d091357d 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb
@@ -45,6 +45,21 @@ module ActiveRecord
           end
         end
 
+        def array_to_string(value, column, adapter, should_be_quoted = false)
+          casted_values = value.map do |val|
+            if String === val
+              if val == "NULL"
+                "\"#{val}\""
+              else
+                quote_and_escape(adapter.type_cast(val, column, true))
+              end
+            else
+              adapter.type_cast(val, column, true)
+            end
+          end
+          "{#{casted_values.join(',')}}"
+        end
+
         def string_to_json(string)
           if String === string
             ActiveSupport::JSON.decode(string)
@@ -71,6 +86,10 @@ module ActiveRecord
           end
         end
 
+        def string_to_array(string, oid)
+          parse_pg_array(string).map{|val| oid.type_cast val}
+        end
+
         private
 
           HstorePair = begin
@@ -90,6 +109,15 @@ module ActiveRecord
               end
             end
           end
+
+          def quote_and_escape(value)
+            case value
+            when "NULL"
+              value
+            else
+              "\"#{value.gsub(/"/,"\\\"")}\""
+            end
+          end
       end
     end
   end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
index b8e7687b21..52344f61c0 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
@@ -63,6 +63,21 @@ module ActiveRecord
           end
         end
 
+        class Array < Type
+          attr_reader :subtype
+          def initialize(subtype)
+            @subtype = subtype
+          end
+
+          def type_cast(value)
+            if String === value
+              ConnectionAdapters::PostgreSQLColumn.string_to_array value, @subtype
+            else
+              value
+            end
+          end
+        end
+
         class Integer < Type
           def type_cast(value)
             return if value.nil?
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
index 85721601a9..37d43d891d 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -19,6 +19,12 @@ module ActiveRecord
           return super unless column
 
           case value
+          when Array
+            if column.array
+              "'#{PostgreSQLColumn.array_to_string(value, column, self)}'"
+            else
+              super
+            end
           when Hash
             case column.sql_type
             when 'hstore' then super(PostgreSQLColumn.hstore_to_string(value), column)
@@ -59,24 +65,35 @@ module ActiveRecord
           end
         end
 
-        def type_cast(value, column)
-          return super unless column
+        def type_cast(value, column, array_member = false)
+          return super(value, column) unless column
 
           case value
+          when NilClass
+            if column.array && array_member
+              'NULL'
+            elsif column.array
+              value
+            else
+              super(value, column)
+            end
+          when Array
+            return super(value, column) unless column.array
+            PostgreSQLColumn.array_to_string(value, column, self)
           when String
-            return super unless 'bytea' == column.sql_type
+            return super(value, column) unless 'bytea' == column.sql_type
             { :value => value, :format => 1 }
           when Hash
             case column.sql_type
             when 'hstore' then PostgreSQLColumn.hstore_to_string(value)
             when 'json' then PostgreSQLColumn.json_to_string(value)
-            else super
+            else super(value, column)
             end
           when IPAddr
-            return super unless ['inet','cidr'].includes? column.sql_type
+            return super(value, column) unless ['inet','cidr'].includes? column.sql_type
             PostgreSQLColumn.cidr_to_string(value)
           else
-            super
+            super(value, column)
           end
         end