Class: HTTP2Next::FrameBuffer

Inherits:
Object
  • Object
show all
Defined in:
lib/http/2/next/flow_buffer.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ FrameBuffer

Returns a new instance of FrameBuffer.



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# File 'lib/http/2/next/flow_buffer.rb', line 106

def initialize
  @buffer = []
  @bytesize = 0
end

Instance Attribute Details

#bytesize ⇒ Object (readonly)

Returns the value of attribute bytesize.



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# File 'lib/http/2/next/flow_buffer.rb', line 104

def bytesize
  @bytesize
end

Instance Method Details

#<<(frame) ⇒ Object 



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# File 'lib/http/2/next/flow_buffer.rb', line 111

def <<(frame)
  @buffer << frame
  @bytesize += frame[:payload].bytesize
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/http/2/next/flow_buffer.rb', line 116

def empty?
  @bytesize == 0
end

#retrieve(window_size) ⇒ Object 



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# File 'lib/http/2/next/flow_buffer.rb', line 120

def retrieve(window_size)
  return if @buffer.empty?

  frame = @buffer.first

  frame_size = frame[:payload].bytesize
  end_stream = frame[:flags].include? :end_stream

  # Frames with zero length with the END_STREAM flag set (that
  # is, an empty DATA frame) MAY be sent if there is no available space
  # in either flow control window.
  return if window_size <= 0 && !(frame_size == 0 && end_stream)

  @buffer.shift

  if frame_size > window_size
    payload = frame.delete(:payload)
    chunk   = frame.dup

    # Split frame so that it fits in the window
    # TODO: consider padding!
    frame_bytes = payload.byteslice(0, window_size)
    payload = payload.byteslice(window_size..-1)

    frame[:payload] = frame_bytes
    frame[:length] = frame_bytes.bytesize
    chunk[:payload] = payload
    chunk[:length]  = payload.bytesize

    # if no longer last frame in sequence...
    frame[:flags] -= [:end_stream] if end_stream

    @buffer.unshift(chunk)
    @bytesize -= window_size
  else
    @bytesize -= frame_size
  end
  frame
end