module ActiveRecord module ConnectionAdapters class SchemaCache attr_reader :version attr_accessor :connection def initialize(conn) @connection = conn @columns = {} @columns_hash = {} @primary_keys = {} @tables = {} prepare_default_proc end def primary_keys(table_name) @primary_keys[table_name] end # A cached lookup for table existence. def table_exists?(name) return @tables[name] if @tables.key? name @tables[name] = connection.table_exists?(name) end # Add internal cache for table with +table_name+. def add(table_name) if table_exists?(table_name) @primary_keys[table_name] @columns[table_name] @columns_hash[table_name] end end def tables(name) @tables[name] end # Get the columns for a table def columns(table) @columns[table] end # Get the columns for a table as a hash, key is the column name # value is the column object. def columns_hash(table) @columns_hash[table] end # Clears out internal caches def clear! @columns.clear @columns_hash.clear @primary_keys.clear @tables.clear @version = nil end def size [@columns, @columns_hash, @primary_keys, @tables].map { |x| x.size }.inject :+ end # Clear out internal caches for table with +table_name+. def clear_table_cache!(table_name) @columns.delete table_name @columns_hash.delete table_name @primary_keys.delete table_name @tables.delete table_name end def marshal_dump # if we get current version during initialization, it happens stack over flow. @version = ActiveRecord::Migrator.current_version [@version] + [@columns, @columns_hash, @primary_keys, @tables].map { |val| Hash[val] } end def marshal_load(array) @version, @columns, @columns_hash, @primary_keys, @tables = array prepare_default_proc end private def prepare_default_proc @columns.default_proc = Proc.new do |h, table_name| h[table_name] = connection.columns(table_name) end @columns_hash.default_proc = Proc.new do |h, table_name| h[table_name] = Hash[columns(table_name).map { |col| [col.name, col] }] end @primary_keys.default_proc = Proc.new do |h, table_name| h[table_name] = table_exists?(table_name) ? connection.primary_key(table_name) : nil end end end end end