1;;; tq.el --- utility to maintain a transaction queue 2 3;; Copyright (C) 1985, 1986, 1987, 1992 Free Software Foundation, Inc. 4 5;; Author: Scott Draves <spot@cs.cmu.edu> 6;; Adapted-By: ESR 7;; Keywords: extensions 8 9;; This file is part of GNU Emacs. 10 11;; GNU Emacs is free software; you can redistribute it and/or modify 12;; it under the terms of the GNU General Public License as published by 13;; the Free Software Foundation; either version 2, or (at your option) 14;; any later version. 15 16;; GNU Emacs is distributed in the hope that it will be useful, 17;; but WITHOUT ANY WARRANTY; without even the implied warranty of 18;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19;; GNU General Public License for more details. 20 21;; You should have received a copy of the GNU General Public License 22;; along with GNU Emacs; see the file COPYING. If not, write to 23;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 24 25;;; Commentary: 26 27;;; manages receiving a stream asynchronously, 28;;; parsing it into transactions, and then calling 29;;; handler functions 30 31;;; Our basic structure is the queue/process/buffer triple. Each entry 32;;; of the queue is a regexp/closure/function triple. We buffer 33;;; bytes from the process until we see the regexp at the head of the 34;;; queue. Then we call the function with the closure and the 35;;; collected bytes. 36 37;;; Code: 38 39;;;###autoload 40(defun tq-create (process) 41 "Create and return a transaction queue communicating with PROCESS. 42PROCESS should be a subprocess capable of sending and receiving 43streams of bytes. It may be a local process, or it may be connected 44to a tcp server on another machine." 45 (let ((tq (cons nil (cons process 46 (generate-new-buffer 47 (concat " tq-temp-" 48 (process-name process))))))) 49 (set-process-filter process 50 (`(lambda (proc string) 51 (tq-filter '(, tq) string)))) 52 tq)) 53 54;;; accessors 55(defun tq-queue (tq) (car tq)) 56(defun tq-process (tq) (car (cdr tq))) 57(defun tq-buffer (tq) (cdr (cdr tq))) 58 59(defun tq-queue-add (tq re closure fn) 60 (setcar tq (nconc (tq-queue tq) 61 (cons (cons re (cons closure fn)) nil))) 62 'ok) 63 64(defun tq-queue-head-regexp (tq) (car (car (tq-queue tq)))) 65(defun tq-queue-head-fn (tq) (cdr (cdr (car (tq-queue tq))))) 66(defun tq-queue-head-closure (tq) (car (cdr (car (tq-queue tq))))) 67(defun tq-queue-empty (tq) (not (tq-queue tq))) 68(defun tq-queue-pop (tq) (setcar tq (cdr (car tq))) (null (car tq))) 69 70 71;;; must add to queue before sending! 72(defun tq-enqueue (tq question regexp closure fn) 73 "Add a transaction to transaction queue TQ. 74This sends the string QUESTION to the process that TQ communicates with. 75When the corresponding answer comes back, we call FN 76with two arguments: CLOSURE, and the answer to the question. 77REGEXP is a regular expression to match the entire answer; 78that's how we tell where the answer ends." 79 (tq-queue-add tq regexp closure fn) 80 (process-send-string (tq-process tq) question)) 81 82(defun tq-close (tq) 83 "Shut down transaction queue TQ, terminating the process." 84 (delete-process (tq-process tq)) 85 (kill-buffer (tq-buffer tq))) 86 87(defun tq-filter (tq string) 88 "Append STRING to the TQ's buffer; then process the new data." 89 (set-buffer (tq-buffer tq)) 90 (goto-char (point-max)) 91 (insert string) 92 (tq-process-buffer tq)) 93 94(defun tq-process-buffer (tq) 95 "Check TQ's buffer for the regexp at the head of the queue." 96 (set-buffer (tq-buffer tq)) 97 (if (= 0 (buffer-size)) () 98 (if (tq-queue-empty tq) 99 (let ((buf (generate-new-buffer "*spurious*"))) 100 (copy-to-buffer buf (point-min) (point-max)) 101 (delete-region (point-min) (point)) 102 (pop-to-buffer buf nil) 103 (error (concat "Spurious communication from process " 104 (process-name (tq-process tq)) 105 ", see buffer *spurious*."))) 106 (goto-char (point-min)) 107 (if (re-search-forward (tq-queue-head-regexp tq) nil t) 108 (let ((answer (buffer-substring (point-min) (point)))) 109 (delete-region (point-min) (point)) 110 (funcall (tq-queue-head-fn tq) 111 (tq-queue-head-closure tq) 112 answer) 113 (tq-queue-pop tq) 114 (tq-process-buffer tq)))))) 115 116(provide 'tq) 117 118;;; tq.el ends here 119