# Copyright, 2018, by Samuel G. D. Williams. # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in # all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN # THE SOFTWARE. require_relative 'window_update_frame' module HTTP module Protocol module HTTP2 module FlowControl def available_frame_size maximum_frame_size = self.maximum_frame_size available_size = @remote_window.available if available_size < maximum_frame_size return available_size else return maximum_frame_size end end # Keep track of the amount of data sent, and fail if is too much. def consume_remote_window(frame) amount = frame.length # 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. if amount.zero? and frame.end_stream? # It's okay, we can send. No need to consume, it's empty anyway. elsif amount >= 0 and amount <= @remote_window.available @remote_window.consume(amount) else raise FlowControlError, "Trying to send #{frame.length} bytes, exceeded window size: #{@remote_window.available} (#{@remote_window})" end end def consume_local_window(frame) amount = frame.length @local_window.consume(amount) if @local_window.limited? self.send_window_update(@local_window.used) end end # Notify the remote end that we are prepared to receive more data: def send_window_update(window_increment) frame = WindowUpdateFrame.new(self.id) frame.pack window_increment write_frame(frame) @local_window.expand(window_increment) end def receive_window_update(frame) was_full = @remote_window.full? # puts "expand remote_window=#{@remote_window} by #{frame.unpack}" @remote_window.expand(frame.unpack) self.window_updated if was_full end def window_updated end end end end end