;;; tq.el --- utility to maintain a transaction queue
-;; Copyright (C) 1985, 1986, 1987, 1992 Free Software Foundation, Inc.
+;; Copyright (C) 1985, 1986, 1987, 1992, 2003 Free Software Foundation, Inc.
;; Author: Scott Draves <spot@cs.cmu.edu>
+;; Maintainer: FSF
;; Adapted-By: ESR
;; Keywords: extensions
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING. If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
;;; Commentary:
-
-;;; manages receiving a stream asynchronously,
-;;; parsing it into transactions, and then calling
-;;; handler functions
-;;; Our basic structure is the queue/process/buffer triple. Each entry
-;;; of the queue is a regexp/closure/function triple. We buffer
-;;; bytes from the process until we see the regexp at the head of the
-;;; queue. Then we call the function with the closure and the
-;;; collected bytes.
+;; manages receiving a stream asynchronously,
+;; parsing it into transactions, and then calling
+;; handler functions
+
+;; Our basic structure is the queue/process/buffer triple. Each entry
+;; of the queue is a regexp/closure/function triple. We buffer
+;; bytes from the process until we see the regexp at the head of the
+;; queue. Then we call the function with the closure and the
+;; collected bytes.
;;; Code:
+;;;###autoload
(defun tq-create (process)
- "Create and return a transaction queue. PROCESS should be 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."
+ "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))))
+ `(lambda (proc string)
+ (tq-filter ',tq string)))
tq))
;;; accessors
(defun tq-queue-head-closure (tq) (car (cdr (car (tq-queue tq)))))
(defun tq-queue-empty (tq) (not (tq-queue tq)))
(defun tq-queue-pop (tq) (setcar tq (cdr (car tq))) (null (car tq)))
-
+
;;; must add to queue before sending!
(defun tq-enqueue (tq question regexp closure fn)
- "Add a transaction to TQ. Send question to the process, and call FN
-with CLOSURE and and the answer, when it appears. The end of the
-answer is identified by REGEXP."
+ "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, 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."
(tq-queue-add tq regexp closure fn)
(process-send-string (tq-process tq) question))
(defun tq-close (tq)
- "Shut down the process, and destroy the evidence."
+ "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."
- (set-buffer (tq-buffer tq))
- (goto-char (point-max))
- (insert string)
- (tq-process-buffer tq))
+ (with-current-buffer (tq-buffer tq)
+ (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."
(copy-to-buffer buf (point-min) (point-max))
(delete-region (point-min) (point))
(pop-to-buffer buf nil)
- (error (concat "Spurious communication from process "
- (process-name (tq-process tq))
- ", see buffer *spurious*.")))
+ (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))
- (funcall (tq-queue-head-fn tq)
- (tq-queue-head-closure tq)
- answer)
- (tq-queue-pop tq)
+ (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)
+;;; arch-tag: 65dea08c-4edd-4cde-83a5-e8a15b993b79
;;; tq.el ends here