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comparison lisp/utils/tq.el @ 0:376386a54a3c r19-14

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Import from CVS: tag r19-14
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date Mon, 13 Aug 2007 08:45:50 +0200
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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 ;;; Synched up with: FSF 19.30.
26
27 ;;; Commentary:
28
29 ;;; manages receiving a stream asynchronously,
30 ;;; parsing it into transactions, and then calling
31 ;;; handler functions
32
33 ;;; Our basic structure is the queue/process/buffer triple. Each entry
34 ;;; of the queue is a regexp/closure/function triple. We buffer
35 ;;; bytes from the process until we see the regexp at the head of the
36 ;;; queue. Then we call the function with the closure and the
37 ;;; collected bytes.
38
39 ;;; Code:
40
41 ;;;###autoload
42 (defun tq-create (process)
43 "Create and return a transaction queue communicating with PROCESS.
44 PROCESS should be a subprocess capable of sending and receiving
45 streams of bytes. It may be a local process, or it may be connected
46 to a tcp server on another machine."
47 (let ((tq (cons nil (cons process
48 (generate-new-buffer
49 (concat " tq-temp-"
50 (process-name process)))))))
51 (set-process-filter process
52 (`(lambda (proc string)
53 (tq-filter '(, tq) string))))
54 tq))
55
56 ;;; accessors
57 (defun tq-queue (tq) (car tq))
58 (defun tq-process (tq) (car (cdr tq)))
59 (defun tq-buffer (tq) (cdr (cdr tq)))
60
61 (defun tq-queue-add (tq re closure fn)
62 (setcar tq (nconc (tq-queue tq)
63 (cons (cons re (cons closure fn)) nil)))
64 'ok)
65
66 (defun tq-queue-head-regexp (tq) (car (car (tq-queue tq))))
67 (defun tq-queue-head-fn (tq) (cdr (cdr (car (tq-queue tq)))))
68 (defun tq-queue-head-closure (tq) (car (cdr (car (tq-queue tq)))))
69 (defun tq-queue-empty (tq) (not (tq-queue tq)))
70 (defun tq-queue-pop (tq) (setcar tq (cdr (car tq))) (null (car tq)))
71
72
73 ;;; must add to queue before sending!
74 (defun tq-enqueue (tq question regexp closure fn)
75 "Add a transaction to transaction queue TQ.
76 This sends the string QUESTION to the process that TQ communicates with.
77 When the corresponding answer comes back, we call FN
78 with two arguments: CLOSURE, and the answer to the question.
79 REGEXP is a regular expression to match the entire answer;
80 that's how we tell where the answer ends."
81 (tq-queue-add tq regexp closure fn)
82 (process-send-string (tq-process tq) question))
83
84 (defun tq-close (tq)
85 "Shut down transaction queue TQ, terminating the process."
86 (delete-process (tq-process tq))
87 (kill-buffer (tq-buffer tq)))
88
89 (defun tq-filter (tq string)
90 "Append STRING to the TQ's buffer; then process the new data."
91 (set-buffer (tq-buffer tq))
92 (goto-char (point-max))
93 (insert string)
94 (tq-process-buffer tq))
95
96 (defun tq-process-buffer (tq)
97 "Check TQ's buffer for the regexp at the head of the queue."
98 (set-buffer (tq-buffer tq))
99 (if (= 0 (buffer-size)) ()
100 (if (tq-queue-empty tq)
101 (let ((buf (generate-new-buffer "*spurious*")))
102 (copy-to-buffer buf (point-min) (point-max))
103 (delete-region (point-min) (point))
104 (pop-to-buffer buf nil)
105 (error (concat "Spurious communication from process "
106 (process-name (tq-process tq))
107 ", see buffer " (buffer-name buf) ".")))
108 (goto-char (point-min))
109 (if (re-search-forward (tq-queue-head-regexp tq) nil t)
110 (let ((answer (buffer-substring (point-min) (point))))
111 (delete-region (point-min) (point))
112 (funcall (tq-queue-head-fn tq)
113 (tq-queue-head-closure tq)
114 answer)
115 (tq-queue-pop tq)
116 (tq-process-buffer tq))))))
117
118 (provide 'tq)
119
120 ;;; tq.el ends here