#lang racket/base

(require racket/set)
(require racket/match)

(require "ssh-numbers.rkt")
(require "ssh-message-types.rkt")
(require "ssh-exceptions.rkt")

(require "os2-support.rkt")

(provide (struct-out ssh-channel))

;; A CloseState is one of
;; - 'neither, indicating that neither side has signalled closure
;; - 'local, only the local end has signalled closure
;; - 'remote, only the remote end has signalled closure
;; - 'both, both ends have signalled closure.
;; Represents local knowledge of the state of a shared shutdown state
;; machine.
;;
;;                'neither
;;                /       \
;;              \/         \/
;;           'local      'remote
;;               \         /
;;                \/     \/
;;                  'both

;; A ChannelState is a (ssh-channel ...) TODO
;; Named ssh-channel to avoid conflicts with Racket's built-in
;; synchronous channels.
(struct ssh-channel (my-ref ;; Uint32
		     your-ref ;; Maybe<Uint32>
		     type ;; String
		     continuations ;; TransactionManager (see ordered-rpc.rkt)
		     outbound-window ;; Maybe<Natural>
		     outbound-packet-size ;; Maybe<Natural>
		     inbound-window ;; Natural
		     eof-state ;; CloseState covering EOF signals
		     close-state ;; CloseState covering CLOSE signals
		     )
	#:transparent)