class Faraday::CompositeReadIO

def advance_io
  @index += 1
end

def close
  @ios.each { |io| io.close }
end

def current_io
  @ios[@index]
end

def ensure_open_and_readable
  # Rubinius compatibility
end

def initialize(*parts)
  @parts = parts.flatten
  @ios = @parts.map { |part| part.to_io }
  @index = 0
end

def length
  @parts.inject(0) { |sum, part| sum + part.length }
end

def read(length = nil, outbuf = nil)
  got_result = false
  outbuf = outbuf ? outbuf.replace("") : ""
  while io = current_io
    if result = io.read(length)
      got_result ||= !result.nil?
      result.force_encoding("BINARY") if result.respond_to?(:force_encoding)
      outbuf << result
      length -= result.length if length
      break if length == 0
    end
    advance_io
  end
  (!got_result && length) ? nil : outbuf
end

def rewind
  @ios.each { |io| io.rewind }
  @index = 0
end