| 1 | ;;; tq.el --- utility to maintain a transaction queue |
| 2 | |
| 3 | ;; Copyright (C) 1985, 1986, 1987, 1992, 2002, 2003, 2004, |
| 4 | ;; 2005, 2006 Free Software Foundation, Inc. |
| 5 | |
| 6 | ;; Author: Scott Draves <spot@cs.cmu.edu> |
| 7 | ;; Maintainer: FSF |
| 8 | ;; Adapted-By: ESR |
| 9 | ;; Keywords: extensions |
| 10 | |
| 11 | ;; This file is part of GNU Emacs. |
| 12 | |
| 13 | ;; GNU Emacs is free software; you can redistribute it and/or modify |
| 14 | ;; it under the terms of the GNU General Public License as published by |
| 15 | ;; the Free Software Foundation; either version 2, or (at your option) |
| 16 | ;; any later version. |
| 17 | |
| 18 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 19 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 21 | ;; GNU General Public License for more details. |
| 22 | |
| 23 | ;; You should have received a copy of the GNU General Public License |
| 24 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
| 25 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| 26 | ;; Boston, MA 02110-1301, USA. |
| 27 | |
| 28 | ;;; Commentary: |
| 29 | |
| 30 | ;; manages receiving a stream asynchronously, |
| 31 | ;; parsing it into transactions, and then calling |
| 32 | ;; handler functions |
| 33 | |
| 34 | ;; Our basic structure is the queue/process/buffer triple. Each entry |
| 35 | ;; of the queue is a regexp/closure/function triple. We buffer |
| 36 | ;; bytes from the process until we see the regexp at the head of the |
| 37 | ;; queue. Then we call the function with the closure and the |
| 38 | ;; collected bytes. |
| 39 | |
| 40 | ;;; Code: |
| 41 | |
| 42 | ;;;###autoload |
| 43 | (defun tq-create (process) |
| 44 | "Create and return a transaction queue communicating with PROCESS. |
| 45 | PROCESS should be a subprocess capable of sending and receiving |
| 46 | streams of bytes. It may be a local process, or it may be connected |
| 47 | to a tcp server on another machine." |
| 48 | (let ((tq (cons nil (cons process |
| 49 | (generate-new-buffer |
| 50 | (concat " tq-temp-" |
| 51 | (process-name process))))))) |
| 52 | (set-process-filter process |
| 53 | `(lambda (proc string) |
| 54 | (tq-filter ',tq string))) |
| 55 | tq)) |
| 56 | |
| 57 | ;;; accessors |
| 58 | (defun tq-queue (tq) (car tq)) |
| 59 | (defun tq-process (tq) (car (cdr tq))) |
| 60 | (defun tq-buffer (tq) (cdr (cdr tq))) |
| 61 | |
| 62 | (defun tq-queue-add (tq re closure fn) |
| 63 | (setcar tq (nconc (tq-queue tq) |
| 64 | (cons (cons re (cons closure fn)) nil))) |
| 65 | 'ok) |
| 66 | |
| 67 | (defun tq-queue-head-regexp (tq) (car (car (tq-queue tq)))) |
| 68 | (defun tq-queue-head-fn (tq) (cdr (cdr (car (tq-queue tq))))) |
| 69 | (defun tq-queue-head-closure (tq) (car (cdr (car (tq-queue tq))))) |
| 70 | (defun tq-queue-empty (tq) (not (tq-queue tq))) |
| 71 | (defun tq-queue-pop (tq) (setcar tq (cdr (car tq))) (null (car tq))) |
| 72 | |
| 73 | |
| 74 | ;;; must add to queue before sending! |
| 75 | (defun tq-enqueue (tq question regexp closure fn) |
| 76 | "Add a transaction to transaction queue TQ. |
| 77 | This sends the string QUESTION to the process that TQ communicates with. |
| 78 | When the corresponding answer comes back, we call FN |
| 79 | with two arguments: CLOSURE, and the answer to the question. |
| 80 | REGEXP is a regular expression to match the entire answer; |
| 81 | that's how we tell where the answer ends." |
| 82 | (tq-queue-add tq regexp closure fn) |
| 83 | (process-send-string (tq-process tq) question)) |
| 84 | |
| 85 | (defun tq-close (tq) |
| 86 | "Shut down transaction queue TQ, terminating the process." |
| 87 | (delete-process (tq-process tq)) |
| 88 | (kill-buffer (tq-buffer tq))) |
| 89 | |
| 90 | (defun tq-filter (tq string) |
| 91 | "Append STRING to the TQ's buffer; then process the new data." |
| 92 | (with-current-buffer (tq-buffer tq) |
| 93 | (goto-char (point-max)) |
| 94 | (insert string) |
| 95 | (tq-process-buffer tq))) |
| 96 | |
| 97 | (defun tq-process-buffer (tq) |
| 98 | "Check TQ's buffer for the regexp at the head of the queue." |
| 99 | (set-buffer (tq-buffer tq)) |
| 100 | (if (= 0 (buffer-size)) () |
| 101 | (if (tq-queue-empty tq) |
| 102 | (let ((buf (generate-new-buffer "*spurious*"))) |
| 103 | (copy-to-buffer buf (point-min) (point-max)) |
| 104 | (delete-region (point-min) (point)) |
| 105 | (pop-to-buffer buf nil) |
| 106 | (error "Spurious communication from process %s, see buffer %s" |
| 107 | (process-name (tq-process tq)) |
| 108 | (buffer-name buf))) |
| 109 | (goto-char (point-min)) |
| 110 | (if (re-search-forward (tq-queue-head-regexp tq) nil t) |
| 111 | (let ((answer (buffer-substring (point-min) (point)))) |
| 112 | (delete-region (point-min) (point)) |
| 113 | (unwind-protect |
| 114 | (condition-case nil |
| 115 | (funcall (tq-queue-head-fn tq) |
| 116 | (tq-queue-head-closure tq) |
| 117 | answer) |
| 118 | (error nil)) |
| 119 | (tq-queue-pop tq)) |
| 120 | (tq-process-buffer tq)))))) |
| 121 | |
| 122 | (provide 'tq) |
| 123 | |
| 124 | ;;; arch-tag: 65dea08c-4edd-4cde-83a5-e8a15b993b79 |
| 125 | ;;; tq.el ends here |