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1 ;;; -*-Emacs-Lisp-*-
2 ;;;%Header
3 ;;; Bridge process filter, V1.0
4 ;;; Copyright (C) 1991 Chris McConnell, ccm@cs.cmu.edu
5 ;;;
6 ;;; Send mail to ilisp@lehman.com if you have problems.
7 ;;;
8 ;;; Send mail to ilisp-request@lehman.com if you want to be on the
9 ;;; ilisp mailing list.
10
11 ;;; This file is part of GNU Emacs.
12
13 ;;; GNU Emacs is distributed in the hope that it will be useful,
14 ;;; but WITHOUT ANY WARRANTY. No author or distributor
15 ;;; accepts responsibility to anyone for the consequences of using it
16 ;;; or for whether it serves any particular purpose or works at all,
17 ;;; unless he says so in writing. Refer to the GNU Emacs General Public
18 ;;; License for full details.
19
20 ;;; Everyone is granted permission to copy, modify and redistribute
21 ;;; GNU Emacs, but only under the conditions described in the
22 ;;; GNU Emacs General Public License. A copy of this license is
23 ;;; supposed to have been given to you along with GNU Emacs so you
24 ;;; can know your rights and responsibilities. It should be in a
25 ;;; file named COPYING. Among other things, the copyright notice
26 ;;; and this notice must be preserved on all copies.
27
28 ;;; Send any bugs or comments. Thanks to Todd Kaufmann for rewriting
29 ;;; the process filter for continuous handlers.
30
31 ;;; USAGE: M-x install-bridge will add a process output filter to the
32 ;;; current buffer. Any output that the process does between
33 ;;; bridge-start-regexp and bridge-end-regexp will be bundled up and
34 ;;; passed to the first handler on bridge-handlers that matches the
35 ;;; output using string-match. If bridge-prompt-regexp shows up
36 ;;; before bridge-end-regexp, the bridge will be cancelled. If no
37 ;;; handler matches the output, the first symbol in the output is
38 ;;; assumed to be a buffer name and the rest of the output will be
39 ;;; sent to that buffer's process. This can be used to communicate
40 ;;; between processes or to set up two way interactions between Emacs
41 ;;; and an inferior process.
42
43 ;;; You can write handlers that process the output in special ways.
44 ;;; See bridge-send-handler for the default handler. The command
45 ;;; hand-bridge is useful for testing. Keep in mind that all
46 ;;; variables are buffer local.
47
48 ;;; YOUR .EMACS FILE:
49 ;;;
50 ;;; ;;; Set up load path to include bridge
51 ;;; (setq load-path (cons "/bridge-directory/" load-path))
52 ;;; (autoload 'install-bridge "bridge" "Install a process bridge." t)
53 ;;; (setq bridge-hook
54 ;;; '(lambda ()
55 ;;; ;; Example options
56 ;;; (setq bridge-source-insert nil) ;Don't insert in source buffer
57 ;;; (setq bridge-destination-insert nil) ;Don't insert in dest buffer
58 ;;; ;; Handle copy-it messages yourself
59 ;;; (setq bridge-handlers
60 ;;; '(("copy-it" . my-copy-handler)))))
61
62 ;;; EXAMPLE:
63 ;;; # This pipes stdin to the named buffer in a Unix shell
64 ;;; alias devgnu '(echo -n "\!* "; cat -; echo -n "")'
65 ;;;
66 ;;; ls | devgnu *scratch*
67
68 ;;;%Parameters
69 (defvar bridge-hook nil
70 "Hook called when a bridge is installed by install-hook.")
71
72 (defvar bridge-start-regexp ""
73 "*Regular expression to match the start of a process bridge in
74 process output. It should be followed by a buffer name, the data to
75 be sent and a bridge-end-regexp.")
76
77 (defvar bridge-end-regexp ""
78 "*Regular expression to match the end of a process bridge in process
79 output.")
80
81 (defvar bridge-prompt-regexp nil
82 "*Regular expression for detecting a prompt. If there is a
83 comint-prompt-regexp, it will be initialized to that. A prompt before
84 a bridge-end-regexp will stop the process bridge.")
85
86 (defvar bridge-handlers nil
87 "Alist of (regexp . handler) for handling process output delimited
88 by bridge-start-regexp and bridge-end-regexp. The first entry on the
89 list whose regexp matches the output will be called on the process and
90 the delimited output.")
91
92 (defvar bridge-source-insert t
93 "*T to insert bridge input in the source buffer minus delimiters.")
94
95 (defvar bridge-destination-insert t
96 "*T for bridge-send-handler to insert bridge input into the
97 destination buffer minus delimiters.")
98
99 (defvar bridge-chunk-size 512
100 "*Long inputs send to comint processes are broken up into chunks of
101 this size. If your process is choking on big inputs, try lowering the
102 value.")
103
104 ;;;%Internal variables
105 (defvar bridge-old-filter nil
106 "Old filter for a bridged process buffer.")
107
108 (defvar bridge-string nil
109 "The current output in the process bridge.")
110
111 (defvar bridge-in-progress nil
112 "The current handler function, if any, that bridge passes strings on to,
113 or nil if none.")
114
115 (defvar bridge-send-to-buffer nil
116 "The buffer that the default bridge-handler (bridge-send-handler) is
117 currently sending to, or nil if it hasn't started yet. Your handler
118 function can use this variable also.")
119
120 (defvar bridge-last-failure ()
121 "Last thing that broke the bridge handler. First item is function call
122 (eval'able); last item is error condition which resulted. This is provided
123 to help handler-writers in their debugging.")
124
125 ;;;%Utilities
126 (defun bridge-insert (output)
127 "Insert process OUTPUT into the current buffer."
128 (if output
129 (let* ((buffer (current-buffer))
130 (process (get-buffer-process buffer))
131 (mark (process-mark process))
132 (window (selected-window))
133 (at-end nil))
134 (if (eq (window-buffer window) buffer)
135 (setq at-end (= (point) mark))
136 (setq window (get-buffer-window buffer)))
137 (save-excursion
138 (goto-char mark)
139 (insert output)
140 (set-marker mark (point)))
141 (if window
142 (progn
143 (if at-end (goto-char mark))
144 (if (not (pos-visible-in-window-p (point) window))
145 (let ((original (selected-window)))
146 (save-excursion
147 (select-window window)
148 (recenter '(center))
149 (select-window original)))))))))
150
151 ;;;
152 (defun bridge-send-string (process string)
153 "Send PROCESS the contents of STRING as input.
154 This is equivalent to process-send-string, except that long input strings
155 are broken up into chunks of size comint-input-chunk-size. Processes
156 are given a chance to output between chunks. This can help prevent processes
157 from hanging when you send them long inputs on some OS's."
158 (let* ((len (length string))
159 (i (min len bridge-chunk-size)))
160 (process-send-string process (substring string 0 i))
161 (while (< i len)
162 (let ((next-i (+ i bridge-chunk-size)))
163 (accept-process-output)
164 (process-send-string process (substring string i (min len next-i)))
165 (setq i next-i)))))
166
167 ;;;
168 (defun bridge-call-handler (handler proc string)
169 "Funcall HANDLER on PROC, STRING carefully. Error is caught if happens,
170 and user is signaled. State is put in bridge-last-failure. Returns t if
171 handler executed without error."
172 (let ((inhibit-quit nil)
173 (failed nil))
174 (condition-case err
175 (funcall handler proc string)
176 (error
177 (ding)
178 (setq failed t)
179 (message "bridge-handler \"%s\" failed %s (see bridge-last-failure)"
180 handler err)
181 (setq bridge-last-failure
182 (` ((funcall '(, handler) '(, proc) (, string))
183 "Caused: "
184 (, err))))))
185 (not failed)))
186
187 ;;;%Handlers
188 (defun bridge-send-handler (process input)
189 "Send PROCESS INPUT to the buffer name found at the start of the
190 input. The input after the buffer name is sent to the buffer's
191 process if it has one. If bridge-destination-insert is T, the input
192 will be inserted into the buffer. If it does not have a process, it
193 will be inserted at the end of the buffer."
194 (if (null input)
195 (setq bridge-send-to-buffer nil) ; end of bridge
196 (let (buffer-and-start buffer-name dest to)
197 ;; if this is first time, get the buffer out of the first line
198 (cond ((not bridge-send-to-buffer)
199 (setq buffer-and-start (read-from-string input)
200 buffer-name (format "%s" (car (read-from-string input)))
201 dest (get-buffer buffer-name)
202 to (get-buffer-process dest)
203 input (substring input (cdr buffer-and-start)))
204 (setq bridge-send-to-buffer dest))
205 (t
206 (setq buffer-name bridge-send-to-buffer
207 dest (get-buffer buffer-name)
208 to (get-buffer-process dest)
209 )))
210 (if dest
211 (let ((buffer (current-buffer)))
212 (if bridge-destination-insert
213 (unwind-protect
214 (progn
215 (set-buffer dest)
216 (if to
217 (bridge-insert input)
218 (goto-char (point-max))
219 (insert input)))
220 (set-buffer buffer)))
221 (if to (bridge-send-string to input)))
222 (error "%s is not a buffer" buffer-name)))))
223
224 ;;;%Filter
225 (defun bridge-filter (process output)
226 "Given PROCESS and some OUTPUT, check for the presence of
227 bridge-start-regexp. Everything prior to this will be passed to the
228 normal filter function or inserted in the buffer if it is nil. The
229 output up to bridge-end-regexp will be sent to the first handler on
230 bridge-handlers that matches the string. If no handlers match, the
231 input will be sent to bridge-send-handler. If bridge-prompt-regexp is
232 encountered before the bridge-end-regexp, the bridge will be cancelled."
233 (let ((inhibit-quit t)
234 (match-data (match-data))
235 (buffer (current-buffer))
236 (process-buffer (process-buffer process))
237 (case-fold-search t)
238 (start 0) (end 0)
239 function
240 b-start b-start-end b-end)
241 (set-buffer process-buffer) ;; access locals
242 (setq function bridge-in-progress)
243
244 ;; How it works:
245 ;;
246 ;; start, end delimit the part of string we are interested in;
247 ;; initially both 0; after an iteration we move them to next string.
248
249 ;; b-start, b-end delimit part of string to bridge (possibly whole string);
250 ;; this will be string between corresponding regexps.
251
252 ;; There are two main cases when we come into loop:
253
254 ;; bridge in progress
255 ;;0 setq b-start = start
256 ;;1 setq b-end (or end-pattern end)
257 ;;4 process string
258 ;;5 remove handler if end found
259
260 ;; no bridge in progress
261 ;;0 setq b-start if see start-pattern
262 ;;1 setq b-end if bstart to (or end-pattern end)
263 ;;2 send (substring start b-start) to normal place
264 ;;3 find handler (in b-start, b-end) if not set
265 ;;4 process string
266 ;;5 remove handler if end found
267
268 ;; equivalent sections have the same numbers here;
269 ;; we fold them together in this code.
270
271 (unwind-protect
272 (while (< end (length output))
273
274 ;;0 setq b-start if find
275 (setq b-start
276 (cond (bridge-in-progress
277 (setq b-start-end start)
278 start)
279 ((string-match bridge-start-regexp output start)
280 (setq b-start-end (match-end 0))
281 (match-beginning 0))
282 (t nil)))
283 ;;1 setq b-end
284 (setq b-end
285 (if b-start
286 (let ((end-seen (string-match bridge-end-regexp
287 output b-start-end)))
288 (if end-seen (setq end (match-end 0)))
289 end-seen)))
290 (if (not b-end) (setq end (length output)
291 b-end (length output)))
292
293 ;;1.5 - if see prompt before end, remove current
294 (if b-start
295 (let ((prompt (string-match bridge-prompt-regexp
296 output b-start-end)))
297 (if (and prompt (<= (match-end 0) b-end))
298 (setq b-start nil ; b-start-end start
299 b-end start
300 end (match-end 0)
301 bridge-in-progress nil
302 ))))
303
304 ;;2 send (substring start b-start) to old filter, if any
305 (if (/= start (or b-start end)) ; don't bother on empty string
306 (let ((pass-on (substring output start (or b-start end))))
307 (if bridge-old-filter
308 (let ((old bridge-old-filter))
309 (store-match-data match-data)
310 (funcall old process pass-on)
311 ;; if filter changed, re-install ourselves
312 (let ((new (process-filter process)))
313 (if (not (eq new 'bridge-filter))
314 (progn (setq bridge-old-filter new)
315 (set-process-filter process 'bridge-filter)))))
316 (set-buffer process-buffer)
317 (bridge-insert pass-on))))
318
319 ;;3 find handler (in b-start, b-end) if none current
320 (if (and b-start (not bridge-in-progress))
321 (let ((handlers bridge-handlers))
322 (while (and handlers (not function))
323 (let* ((handler (car handlers))
324 (m (string-match (car handler) output b-start-end)))
325 (if (and m (< m b-end))
326 (setq function (cdr handler))
327 (setq handlers (cdr handlers)))))
328 ;; Set default handler if none
329 (if (null function)
330 (setq function 'bridge-send-handler))
331 (setq bridge-in-progress function)))
332 ;;4 process string
333 (if function
334 (let ((ok t))
335 (if (/= b-start-end b-end)
336 (let ((send (substring output b-start-end b-end)))
337 ;; also, insert the stuff in buffer between
338 ;; iff bridge-source-insert.
339 (if bridge-source-insert (bridge-insert send))
340 ;; call handler on string
341 (setq ok (bridge-call-handler function process send))))
342 ;;5 remove handler if end found
343 ;; if function removed then tell it that's all
344 (if (or (not ok) (/= b-end end));; saw end before end-of-string
345 (progn
346 (bridge-call-handler function process nil)
347 ;; have to remove function too for next time around
348 (setq function nil
349 bridge-in-progress nil)
350 ))
351 ))
352
353 ;; continue looping, in case there's more string
354 (setq start end)
355 ))
356 ;; protected forms: restore buffer, match-data
357 (set-buffer buffer)
358 (store-match-data match-data)
359 ))
360
361 ;;;%Interface
362 (defun install-bridge ()
363 "Set up a process bridge in the current buffer."
364 (interactive)
365 (if (not (get-buffer-process (current-buffer)))
366 (error "%s does not have a process" (buffer-name (current-buffer)))
367 (make-local-variable 'bridge-start-regexp)
368 (make-local-variable 'bridge-end-regexp)
369 (make-local-variable 'bridge-prompt-regexp)
370 (make-local-variable 'bridge-handlers)
371 (make-local-variable 'bridge-source-insert)
372 (make-local-variable 'bridge-destination-insert)
373 (make-local-variable 'bridge-chunk-size)
374 (make-local-variable 'bridge-old-filter)
375 (make-local-variable 'bridge-string)
376 (make-local-variable 'bridge-in-progress)
377 (make-local-variable 'bridge-send-to-buffer)
378 (setq bridge-string nil bridge-in-progress nil
379 bridge-send-to-buffer nil)
380 (if (boundp 'comint-prompt-regexp)
381 (setq bridge-prompt-regexp comint-prompt-regexp))
382 (let ((process (get-buffer-process (current-buffer))))
383 (if process
384 (if (not (eq (process-filter process) 'bridge-filter))
385 (progn
386 (setq bridge-old-filter (process-filter process))
387 (set-process-filter process 'bridge-filter)))
388 (error "%s does not have a process"
389 (buffer-name (current-buffer)))))
390 (run-hooks 'bridge-hook)
391 (message "Process bridge is installed")))
392
393 ;;;
394 (defun reset-bridge ()
395 "Must be called from the process's buffer. Removes any active bridge."
396 (interactive)
397 ;; for when things get wedged
398 (if bridge-in-progress
399 (unwind-protect
400 (funcall bridge-in-progress (get-buffer-process
401 (current-buffer))
402 nil)
403 (setq bridge-in-progress nil))
404 (message "No bridge in progress.")))
405
406 ;;;
407 (defun remove-bridge ()
408 "Remove bridge from the current buffer."
409 (interactive)
410 (let ((process (get-buffer-process (current-buffer))))
411 (if (or (not process) (not (eq (process-filter process) 'bridge-filter)))
412 (error "%s has no bridge" (buffer-name (current-buffer)))
413 ;; remove any bridge-in-progress
414 (reset-bridge)
415 (set-process-filter process bridge-old-filter)
416 (funcall bridge-old-filter process bridge-string)
417 (message "Process bridge is removed."))))
418
419 ;;;% Utility for testing
420 (defun hand-bridge (start end)
421 "With point at bridge-start, sends bridge-start + string +
422 bridge-end to bridge-filter. With prefix, use current region to send."
423 (interactive "r")
424 (let ((p0 (if current-prefix-arg (min start end)
425 (if (looking-at bridge-start-regexp) (point)
426 (error "Not looking at bridge-start-regexp"))))
427 (p1 (if current-prefix-arg (max start end)
428 (if (re-search-forward bridge-end-regexp nil t)
429 (point) (error "Didn't see bridge-end-regexp")))))
430
431 (bridge-filter (get-buffer-process (current-buffer))
432 (buffer-substring p0 p1))
433 ))
434
435 (provide 'bridge)