(PENDING_OUTPUT_COUNT): Two alternate definitions
[bpt/emacs.git] / lisp / emacs-lisp / tq.el
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1;;; tq.el --- utility to maintain a transaction queue
2
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3;; Copyright (C) 1985, 1986, 1987, 1992 Free Software Foundation, Inc.
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5;; Author: Scott Draves <spot@cs.cmu.edu>
6;; Adapted-By: ESR
d7b4d18f 7;; Keywords: extensions
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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:
83023647 26
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27;;; manages receiving a stream asynchronously,
28;;; parsing it into transactions, and then calling
29;;; handler functions
30
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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
83023647 37;;; Code:
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09f11993 39;;;###autoload
abeffda9 40(defun tq-create (process)
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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."
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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)
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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."
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79 (tq-queue-add tq regexp closure fn)
80 (process-send-string (tq-process tq) question))
81
82(defun tq-close (tq)
09f11993 83 "Shut down transaction queue TQ, terminating the process."
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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
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116(provide 'tq)
117
abeffda9 118;;; tq.el ends here