logged-stream.lisp

(defpackage logged-stream
  (:use cl trivial-gray-streams)
  (:import-from flexi-streams make-in-memory-output-stream get-output-stream-sequence)
  (:export make-logged-stream get-input get-ouput))
(in-package logged-stream)

(defclass logged-stream (fundamental-binary-output-stream fundamental-binary-input-stream)
  ((stream :initarg :stream :accessor base-stream)
   (input :initform (make-in-memory-output-stream) :accessor logged-input)
   (output :initform (make-in-memory-output-stream) :accessor logged-output)))

(defun make-logged-stream (stream)
  (make-instance 'logged-stream :stream stream))

(defun get-input (stream)
  (get-output-stream-sequence (logged-input stream)))

(defun get-output (stream)
  (get-output-stream-sequence (logged-output stream)))

(defmethod stream-read-sequence ((stream logged-stream) sequence start end &key &allow-other-keys)
  (with-slots (stream input) stream
    (prog1 (read-sequence sequence stream :start start :end end)
      (write-sequence sequence input :start start :end end))))

(defmethod stream-write-sequence ((stream logged-stream) sequence start end &key &allow-other-keys)
  (with-slots (stream output) stream
    (write-sequence sequence output :start start :end end)
    (write-sequence sequence stream :start start :end end)))

(defmethod stream-force-output ((stream logged-stream))
  (force-output (base-stream stream)))