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abeffda9 ER |
1 | ;;; tq.el --- utility to maintain a transaction queue |
2 | ||
83023647 ER |
3 | ;; Author: Scott Draves <spot@cs.cmu.edu> |
4 | ;; Adapted-By: ESR | |
d7b4d18f | 5 | ;; Keywords: extensions |
83023647 ER |
6 | |
7 | ;; Commentary: | |
8 | ||
abeffda9 ER |
9 | ;;; manages receiving a stream asynchronously, |
10 | ;;; parsing it into transactions, and then calling | |
11 | ;;; handler functions | |
12 | ||
abeffda9 ER |
13 | ;;; Our basic structure is the queue/process/buffer triple. Each entry |
14 | ;;; of the queue is a regexp/closure/function triple. We buffer | |
15 | ;;; bytes from the process until we see the regexp at the head of the | |
16 | ;;; queue. Then we call the function with the closure and the | |
17 | ;;; collected bytes. | |
18 | ||
83023647 | 19 | ;;; Code: |
abeffda9 ER |
20 | |
21 | (provide 'tq) | |
22 | ||
23 | (defun tq-create (process) | |
24 | "Create and return a transaction queue. PROCESS should be capable | |
25 | of sending and receiving streams of bytes. It may be a local process, | |
26 | or it may be connected to a tcp server on another machine." | |
27 | (let ((tq (cons nil (cons process | |
28 | (generate-new-buffer | |
29 | (concat " tq-temp-" | |
30 | (process-name process))))))) | |
31 | (set-process-filter process | |
32 | (`(lambda (proc string) | |
33 | (tq-filter '(, tq) string)))) | |
34 | tq)) | |
35 | ||
36 | ;;; accessors | |
37 | (defun tq-queue (tq) (car tq)) | |
38 | (defun tq-process (tq) (car (cdr tq))) | |
39 | (defun tq-buffer (tq) (cdr (cdr tq))) | |
40 | ||
41 | (defun tq-queue-add (tq re closure fn) | |
42 | (setcar tq (nconc (tq-queue tq) | |
43 | (cons (cons re (cons closure fn)) nil))) | |
44 | 'ok) | |
45 | ||
46 | (defun tq-queue-head-regexp (tq) (car (car (tq-queue tq)))) | |
47 | (defun tq-queue-head-fn (tq) (cdr (cdr (car (tq-queue tq))))) | |
48 | (defun tq-queue-head-closure (tq) (car (cdr (car (tq-queue tq))))) | |
49 | (defun tq-queue-empty (tq) (not (tq-queue tq))) | |
50 | (defun tq-queue-pop (tq) (setcar tq (cdr (car tq))) (null (car tq))) | |
51 | ||
52 | ||
53 | ;;; must add to queue before sending! | |
54 | (defun tq-enqueue (tq question regexp closure fn) | |
55 | "Add a transaction to TQ. Send question to the process, and call FN | |
56 | with CLOSURE and and the answer, when it appears. The end of the | |
57 | answer is identified by REGEXP." | |
58 | (tq-queue-add tq regexp closure fn) | |
59 | (process-send-string (tq-process tq) question)) | |
60 | ||
61 | (defun tq-close (tq) | |
62 | "Shut down the process, and destroy the evidence." | |
63 | (delete-process (tq-process tq)) | |
64 | (kill-buffer (tq-buffer tq))) | |
65 | ||
66 | (defun tq-filter (tq string) | |
67 | "Append STRING to the TQ's buffer; then process the new data." | |
68 | (set-buffer (tq-buffer tq)) | |
69 | (goto-char (point-max)) | |
70 | (insert string) | |
71 | (tq-process-buffer tq)) | |
72 | ||
73 | (defun tq-process-buffer (tq) | |
74 | "Check TQ's buffer for the regexp at the head of the queue." | |
75 | (set-buffer (tq-buffer tq)) | |
76 | (if (= 0 (buffer-size)) () | |
77 | (if (tq-queue-empty tq) | |
78 | (let ((buf (generate-new-buffer "*spurious*"))) | |
79 | (copy-to-buffer buf (point-min) (point-max)) | |
80 | (delete-region (point-min) (point)) | |
81 | (pop-to-buffer buf nil) | |
82 | (error (concat "Spurious communication from process " | |
83 | (process-name (tq-process tq)) | |
84 | ", see buffer *spurious*."))) | |
85 | (goto-char (point-min)) | |
86 | (if (re-search-forward (tq-queue-head-regexp tq) nil t) | |
87 | (let ((answer (buffer-substring (point-min) (point)))) | |
88 | (delete-region (point-min) (point)) | |
89 | (funcall (tq-queue-head-fn tq) | |
90 | (tq-queue-head-closure tq) | |
91 | answer) | |
92 | (tq-queue-pop tq) | |
93 | (tq-process-buffer tq)))))) | |
94 | ||
95 | ;;; tq.el ends here |