class Vips::Object

def self.print_all
  GC.start
  Vips.vips_object_print_all
end

def get name
  gtype = get_typeof_error name
  gvalue = GObject::GValue.alloc
  gvalue.init gtype
  GObject.g_object_get_property self, name, gvalue
  result = gvalue.get
  gvalue.unset
  GLib.logger.debug("Vips::Object.get") { "#{name} == #{result}" }
  result
end

def get_pspec name
  ppspec = GObject::GParamSpecPtr.new
  argument_class = Vips::ArgumentClassPtr.new
  argument_instance = Vips::ArgumentInstancePtr.new
  result = Vips.vips_object_get_argument self, name,
    ppspec, argument_class, argument_instance
  return nil if result != 0
  ppspec[:value]
end

def get_typeof name
  pspec = get_pspec name
  unless pspec
    Vips.vips_error_clear
    return 0
  end
  pspec[:value_type]
end

def get_typeof_error name
  pspec = get_pspec name
  raise Vips::Error unless pspec
  pspec[:value_type]
end

def set name, value
  GLib.logger.debug("Vips::Object.set") { "#{name} = #{value}" }
  gtype = get_typeof_error name
  gvalue = GObject::GValue.alloc
  gvalue.init gtype
  gvalue.set value
  GObject.g_object_set_property self, name, gvalue
  gvalue.unset
end

def signal_connect name, handler = nil, &block
  marshal = MARSHAL_ALL[name.to_sym]
  raise Vips::Error, "unsupported signal #{name}" if marshal.nil?
  if block
    # our block as a Proc
    prc = block
  elsif handler
    # We assume the hander is a Proc (perhaps we should test)
    prc = handler
  else
    raise Vips::Error, "must supply either block or handler"
  end
  # The marshal function will make a closure with the right type signature
  # for the selected signal
  callback = marshal.call(prc)
  # we need to make sure this is not GCd while self is alive
  @references << callback
  GObject.g_signal_connect_data(self, name.to_s, callback, nil, nil, 0)
end