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using Plum::BinaryString
module Plum
class Stream
include FlowControl
include StreamUtils
attr_reader :id, :state, :connection
attr_reader :weight, :exclusive
attr_accessor :parent
def initialize(con, id, state: :idle, weight: 16, parent: nil, exclusive: false)
@connection = con
@id = id
@state = state
@continuation = []
initialize_flow_control(send: @connection.remote_settings[:initial_window_size],
recv: @connection.local_settings[:initial_window_size])
update_dependency(weight: weight, parent: parent, exclusive: exclusive)
end
# Returns the child (depending on this stream) streams.
#
# @return [Array<Stream>] The child streams.
def children
@connection.streams.values.select {|c| c.parent == self }.freeze
end
# Processes received frames for this stream. Internal use.
# @private
def receive_frame(frame)
validate_received_frame(frame)
consume_recv_window(frame)
case frame.type
when :data
receive_data(frame)
when :headers
receive_headers(frame)
when :priority
receive_priority(frame)
when :rst_stream
receive_rst_stream(frame)
when :window_update
receive_window_update(frame)
when :continuation
receive_continuation(frame)
when :ping, :goaway, :settings, :push_promise
raise ConnectionError.new(:protocol_error) # stream_id MUST be 0x00
else
# MUST ignore unknown frame
end
rescue StreamError => e
connection.callback(:stream_error, self, e)
close(e.http2_error_type)
end
# Closes this stream. Sends RST_STREAM frame to the peer.
#
# @param error_type [Symbol] The error type to be contained in the RST_STREAM frame.
def close(error_type = :no_error)
@state = :closed
send_immediately Frame.rst_stream(id, error_type)
end
private
def send_immediately(frame)
callback(:send_frame, frame)
@connection.send(frame)
end
def update_dependency(weight: nil, parent: nil, exclusive: nil)
raise StreamError.new(:protocol_error, "A stream cannot depend on itself.") if parent == self
@weight = weight unless weight.nil?
@parent = parent unless parent.nil?
@exclusive = exclusive unless exclusive.nil?
if exclusive == true
parent.children.each do |child|
next if child == self
child.parent = self
end
end
end
def validate_received_frame(frame)
if frame.length > @connection.local_settings[:max_frame_size]
if [:headers, :push_promise, :continuation].include?(frame.type)
raise ConnectionError.new(:frame_size_error)
else
raise StreamError.new(:frame_size_error)
end
end
end
def receive_end_stream
connection.callback(:end_stream, self)
@state = :half_closed_remote
end
def receive_data(frame)
if @state != :open && @state != :half_closed_local
raise StreamError.new(:stream_closed)
end
if frame.padded?
padding_length = frame.payload.uint8(0)
if padding_length >= frame.length
raise ConnectionError.new(:protocol_error, "padding is too long")
end
body = frame.payload.byteslice(1, frame.length - padding_length - 1)
else
body = frame.payload
end
connection.callback(:data, self, body)
receive_end_stream if frame.end_stream?
end
def receive_complete_headers(frames)
first = frames.shift
payload = first.payload
first_length = first.length
padding_length = 0
if first.padded?
padding_length = payload.uint8
first_length -= 1 + padding_length
payload = payload.byteslice(1, first_length)
else
payload = payload.dup
end
if first.priority?
receive_priority_payload(payload.byteshift(5))
first_length -= 5
end
if padding_length > first_length
raise ConnectionError.new(:protocol_error, "padding is too long")
end
frames.each do |frame|
payload << frame.payload
end
begin
decoded_headers = @connection.hpack_decoder.decode(payload)
rescue => e
raise ConnectionError.new(:compression_error, e)
end
connection.callback(:headers, self, decoded_headers)
receive_end_stream if first.end_stream?
end
def receive_headers(frame)
if @state == :reserved_local
raise ConnectionError.new(:protocol_error)
elsif @state == :half_closed_remote
raise StreamError.new(:stream_closed)
elsif @state == :closed
raise ConnectionError.new(:stream_closed)
end
@state = :open
connection.callback(:open, self)
if frame.end_headers?
receive_complete_headers([frame])
else
@continuation << frame
end
end
def receive_continuation(frame)
# state error mustn't happen: server_connection validates
@continuation << frame
if frame.end_headers?
receive_complete_headers(@continuation)
@continuation.clear
end
end
def receive_priority(frame)
if frame.length != 5
raise StreamError.new(:frame_size_error)
end
receive_priority_payload(frame.payload)
end
def receive_priority_payload(payload)
esd = payload.uint32
e = esd >> 31
dependency_id = e & ~(1 << 31)
weight = payload.uint8(4)
update_dependency(weight: weight, parent: @connection.streams[dependency_id], exclusive: e == 1)
end
def receive_rst_stream(frame)
if frame.length != 4
raise ConnectionError.new(:frame_size_error)
elsif @state == :idle
raise ConnectionError.new(:protocol_error)
end
connection.callback(:rst_stream, self, frame)
@state = :closed # MUST NOT send RST_STREAM
end
end
end
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