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