(defun tq-queue (tq) (car tq))
(defun tq-process (tq) (car (cdr tq)))
(defun tq-buffer (tq) (cdr (cdr tq)))
(defun tq-queue-head-question (tq) (car (car (tq-queue tq))))
(defun tq-queue-head-regexp (tq) (car (cdr (car (tq-queue tq)))))
(defun tq-queue-head-closure (tq) (car (cdr (cdr (car (tq-queue tq))))))
(defun tq-queue-head-fn (tq) (cdr (cdr (cdr (car (tq-queue tq))))))
(defun tq-queue-empty (tq) (not (tq-queue tq)))
(defun tq-create (process)
"Create and return a transaction queue communicating with PROCESS.
PROCESS should be a subprocess capable of sending and receiving
streams of bytes. It may be a local process, or it may be connected
to a tcp server on another machine."
(let ((tq (cons nil (cons process
(generate-new-buffer
(concat " tq-temp-"
(process-name process)))))))
(set-process-filter process
`(lambda (proc string)
(tq-filter ',tq string)))
tq))
(defun tq-queue-add (tq question re closure fn)
(setcar tq (nconc (tq-queue tq)
(cons (cons question (cons re (cons closure fn))) nil)))
'ok)
(defun tq-queue-pop (tq)
(setcar tq (cdr (car tq)))
(let ((question (tq-queue-head-question tq)))
(when question
(process-send-string (tq-process tq) question)))
(null (car tq)))
(defun tq-enqueue (tq question regexp closure fn &optional delay-question)
"Add a transaction to transaction queue TQ.
This sends the string QUESTION to the process that TQ communicates with.
When the corresponding answer comes back, we call FN with two
arguments: CLOSURE, which may contain additional data that FN
needs, and the answer to the question.
REGEXP is a regular expression to match the entire answer;
that's how we tell where the answer ends.
If DELAY-QUESTION is non-nil, delay sending this question until
the process has finished replying to any previous questions.
This produces more reliable results with some processes."
(let ((sendp (or (not delay-question)
(not (tq-queue tq)))))
(tq-queue-add tq (unless sendp question) regexp closure fn)
(when sendp
(process-send-string (tq-process tq) question))))
(defun tq-close (tq)
"Shut down transaction queue TQ, terminating the process."
(delete-process (tq-process tq))
(kill-buffer (tq-buffer tq)))
(defun tq-filter (tq string)
"Append STRING to the TQ's buffer; then process the new data."
(let ((buffer (tq-buffer tq)))
(when (buffer-live-p buffer)
(with-current-buffer buffer
(goto-char (point-max))
(insert string)
(tq-process-buffer tq)))))
(defun tq-process-buffer (tq)
"Check TQ's buffer for the regexp at the head of the queue."
(let ((buffer (tq-buffer tq)))
(when (buffer-live-p buffer)
(set-buffer buffer)
(if (= 0 (buffer-size)) ()
(if (tq-queue-empty tq)
(let ((buf (generate-new-buffer "*spurious*")))
(copy-to-buffer buf (point-min) (point-max))
(delete-region (point-min) (point))
(pop-to-buffer buf nil)
(error "Spurious communication from process %s, see buffer %s"
(process-name (tq-process tq))
(buffer-name buf)))
(goto-char (point-min))
(if (re-search-forward (tq-queue-head-regexp tq) nil t)
(let ((answer (buffer-substring (point-min) (point))))
(delete-region (point-min) (point))
(unwind-protect
(condition-case nil
(funcall (tq-queue-head-fn tq)
(tq-queue-head-closure tq)
answer)
(error nil))
(tq-queue-pop tq))
(tq-process-buffer tq))))))))
(provide 'tq)