Class: RBus::Message::Reader

Inherits:
Object
  • Object
show all
Includes:
HeaderFields, MessageTypes
Defined in:
lib/rbus/message/reader.rb

Overview

Reads and parses a message

Constant Summary

Constants included from HeaderFields

HeaderFields::DESTINATION, HeaderFields::ERROR_NAME, HeaderFields::INTERFACE, HeaderFields::MEMBER, HeaderFields::PATH, HeaderFields::REPLY_SERIAL, HeaderFields::SENDER, HeaderFields::SIGNATURE

Constants included from MessageTypes

MessageTypes::ERROR, MessageTypes::INVALID, MessageTypes::METHOD_CALL, MessageTypes::METHOD_RETURN, MessageTypes::SIGNAL

Instance Method Summary collapse

Constructor Details

#initialize(transport) ⇒ Reader

Returns a new instance of Reader.



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# File 'lib/rbus/message/reader.rb', line 32

def initialize(transport)
  @transport = transport
end

Instance Method Details

#read_message ⇒ Object

Read one message from the transport, unmarshal and return



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# File 'lib/rbus/message/reader.rb', line 37

def read_message
  header = @transport.read(12)
  return nil if header.nil?
  
  endian = header.dbus_unmarshal('y')
  header_info = header.dbus_unmarshal('yyyyuu', endian)
  
  unless header_info[3] == VERSION::PROTOCOL
    raise InvalidProtocolException, "Message with version '#{header_info[3]}'"
  end
  
  # Read first header length, then header fields
  hl_raw = @transport.read(4)
  header_length = hl_raw.dbus_unmarshal('u', endian)
  hf_raw = @transport.read(header_length)
  
  # Hack:
  # The padding in the middle is because we do not start on a
  # 8-byte boundary and the dbus_marshal method is doing the
  # right thing... it's a TODO. :)
  header_fields = (hl_raw + "\0\0\0\0" + hf_raw).dbus_unmarshal('a(yv)', endian)

  # Go to 8-byte boundary
  @transport.read(-(header+hl_raw+hf_raw).length & 7)

  body = @transport.read(header_info[4])
  #Log.debug(body)

  klass = 
    case header_info[1]
      when METHOD_CALL
        MethodCall
      when METHOD_RETURN
        MethodReturn
      when ERROR
        Error
      when SIGNAL
        Signal
      else
        raise MessageException, "Invalid message type #{header_info[1]}"
    end

  message = klass.new
  message.flags = header_info[2]

  header_fields.each do |hf|
    case hf[0]
      when PATH
        message.object_path = hf[1].object
      when INTERFACE
        message.interface = hf[1].object
      when MEMBER
        message.member = hf[1].object
      when ERROR_NAME
        # TODO
      when REPLY_SERIAL
        message.serial = hf[1].object
      when DESTINATION
        message.destination = hf[1].object
      when SENDER
        message.sender = hf[1].object
      when SIGNATURE
        message.signature = hf[1].object
        message.arguments = body.dbus_unmarshal(hf[1].object, endian)
    end
  end
  #Log.debug(message)
  message
end