Class: QuartzTorrent::ExtendedMetaInfo

Inherits:
Extended show all
Defined in:
lib/quartz_torrent/peermsg.rb

Overview

An Extended Metainfo message. Used to request metadata pieces, or provide responses to those requests.

Constant Summary

Constants inherited from PeerWireMessage

PeerWireMessage::MessageBitfield, PeerWireMessage::MessageCancel, PeerWireMessage::MessageChoke, PeerWireMessage::MessageExtended, PeerWireMessage::MessageHave, PeerWireMessage::MessageInterested, PeerWireMessage::MessageKeepAlive, PeerWireMessage::MessagePiece, PeerWireMessage::MessageRequest, PeerWireMessage::MessageUnchoke, PeerWireMessage::MessageUninterested

Instance Attribute Summary collapse

Attributes inherited from Extended

#extendedMessageId

Attributes inherited from PeerWireMessage

#messageId

Instance Method Summary collapse

Methods inherited from Extended

#payloadLength, #to_s

Methods inherited from PeerWireMessage

#length, #payloadLength, #to_s

Constructor Details

#initialize ⇒ ExtendedMetaInfo

Returns a new instance of ExtendedMetaInfo.



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# File 'lib/quartz_torrent/peermsg.rb', line 407

def initialize
  super()
  @extendedMessageId = 0
  @msgType = nil
  @piece = nil
  @totalSize = nil
  @data = nil
  @dict = {}
end

Instance Attribute Details

#data ⇒ Object

This field is only set if the msgType is :piece. It contains the data for the piece.



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# File 'lib/quartz_torrent/peermsg.rb', line 424

def data
  @data
end

#dict ⇒ Object

Returns the value of attribute dict.



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# File 'lib/quartz_torrent/peermsg.rb', line 417

def dict
  @dict
end

#msgType ⇒ Object

Message type as a symbol. One of :request, :data, or :reject



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# File 'lib/quartz_torrent/peermsg.rb', line 419

def msgType
  @msgType
end

#piece ⇒ Object

Returns the value of attribute piece.



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# File 'lib/quartz_torrent/peermsg.rb', line 420

def piece
  @piece
end

#totalSize ⇒ Object

This field is only set if the msgType is :piece



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# File 'lib/quartz_torrent/peermsg.rb', line 422

def totalSize
  @totalSize
end

Instance Method Details

#serializeTo(io) ⇒ Object 



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# File 'lib/quartz_torrent/peermsg.rb', line 470

def serializeTo(io)
  super(io)
  updateDictFromProps
  io.write @dict.bencode
  raise "Extended metainfo piece messages must have piece data. This one's data was nil" if ! @data && dict['msg_type'] == 1
  io.write @data if dict['msg_type'] == 1
end

#unserialize(payload) ⇒ Object 



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# File 'lib/quartz_torrent/peermsg.rb', line 426

def unserialize(payload)
  # Unserialize extended message id
  super(payload)

  # Rest of the message is a bencoded dictionary.
  # Piece messages of this class are encoded in an interesting way: the bencoded dictionary
  # is concatenated with the arbitrary binary data of the piece at the end. To decode this
  # we need to know the position of when we've finished reading the dictionary. We do this by
  # using a Parser object from the bencode library which maintains a stream object which happens
  # to know the current offset of the parsing.

  payload = payload[1,payload.length]
  parser = BEncode::Parser.new payload

  begin
    @dict = parser.parse!
  rescue
    e = RuntimeError.new("Error bdecoding payload '#{payload}' (payload length = #{payload.length})")
    e.set_backtrace($!.backtrace)
    raise e
  end

  @msgType = @dict['msg_type']
  raise "Extended Metainfo message contained no 'msg_type' key." if ! @msgType
  if @msgType == 0
    @msgType = :request
  elsif @msgType == 1
    @msgType = :piece
  elsif @msgType == 2
    @msgType = :reject
  else
    raise "Unknown message type '#{@msgType}' in Extended Metainfo message"
  end

  @piece = @dict['piece']
  raise "Extended Metainfo message contained no 'piece' key." if ! @piece
  
  @totalSize = @dict['total_size'] if @msgType == :piece

  # If this is a piece message, read the data after the dictionary.
  @data = parser.stream.read if @msgType == :piece
  
end