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eec82323 | 1 | ;;; nnvirtual.el --- virtual newsgroups access for Gnus |
6748645f | 2 | ;; Copyright (C) 1994,95,96,97,98 Free Software Foundation, Inc. |
eec82323 LMI |
3 | |
4 | ;; Author: David Moore <dmoore@ucsd.edu> | |
6748645f | 5 | ;; Lars Magne Ingebrigtsen <larsi@gnus.org> |
eec82323 LMI |
6 | ;; Masanobu UMEDA <umerin@flab.flab.fujitsu.junet> |
7 | ;; Keywords: news | |
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 the | |
23 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
24 | ;; Boston, MA 02111-1307, USA. | |
25 | ||
26 | ;;; Commentary: | |
27 | ||
28 | ;; The other access methods (nntp, nnspool, etc) are general news | |
29 | ;; access methods. This module relies on Gnus and can not be used | |
30 | ;; separately. | |
31 | ||
32 | ;;; Code: | |
33 | ||
34 | (require 'nntp) | |
35 | (require 'nnheader) | |
36 | (require 'gnus) | |
37 | (require 'nnoo) | |
38 | (require 'gnus-util) | |
39 | (require 'gnus-start) | |
40 | (require 'gnus-sum) | |
6748645f | 41 | (require 'gnus-msg) |
eec82323 LMI |
42 | (eval-when-compile (require 'cl)) |
43 | ||
44 | (nnoo-declare nnvirtual) | |
45 | ||
6748645f | 46 | (defvoo nnvirtual-always-rescan t |
eec82323 LMI |
47 | "*If non-nil, always scan groups for unread articles when entering a group. |
48 | If this variable is nil (which is the default) and you read articles | |
49 | in a component group after the virtual group has been activated, the | |
50 | read articles from the component group will show up when you enter the | |
51 | virtual group.") | |
52 | ||
53 | (defvoo nnvirtual-component-regexp nil | |
54 | "*Regexp to match component groups.") | |
55 | ||
56 | (defvoo nnvirtual-component-groups nil | |
57 | "Component group in this nnvirtual group.") | |
58 | ||
59 | \f | |
60 | ||
61 | (defconst nnvirtual-version "nnvirtual 1.1") | |
62 | ||
63 | (defvoo nnvirtual-current-group nil) | |
64 | ||
65 | (defvoo nnvirtual-mapping-table nil | |
66 | "Table of rules on how to map between component group and article number | |
67 | to virtual article number.") | |
68 | ||
69 | (defvoo nnvirtual-mapping-offsets nil | |
70 | "Table indexed by component group to an offset to be applied to article numbers in that group.") | |
71 | ||
72 | (defvoo nnvirtual-mapping-len 0 | |
73 | "Number of articles in this virtual group.") | |
74 | ||
75 | (defvoo nnvirtual-mapping-reads nil | |
76 | "Compressed sequence of read articles on the virtual group as computed from the unread status of individual component groups.") | |
77 | ||
78 | (defvoo nnvirtual-mapping-marks nil | |
79 | "Compressed marks alist for the virtual group as computed from the marks of individual component groups.") | |
80 | ||
81 | (defvoo nnvirtual-info-installed nil | |
82 | "T if we have already installed the group info for this group, and shouldn't blast over it again.") | |
83 | ||
84 | (defvoo nnvirtual-status-string "") | |
85 | ||
86 | (eval-and-compile | |
87 | (autoload 'gnus-cache-articles-in-group "gnus-cache")) | |
88 | ||
89 | \f | |
90 | ||
91 | ;;; Interface functions. | |
92 | ||
93 | (nnoo-define-basics nnvirtual) | |
94 | ||
95 | ||
96 | (deffoo nnvirtual-retrieve-headers (articles &optional newsgroup | |
97 | server fetch-old) | |
98 | (when (nnvirtual-possibly-change-server server) | |
99 | (save-excursion | |
100 | (set-buffer nntp-server-buffer) | |
101 | (erase-buffer) | |
102 | (if (stringp (car articles)) | |
103 | 'headers | |
104 | (let ((vbuf (nnheader-set-temp-buffer | |
105 | (get-buffer-create " *virtual headers*"))) | |
106 | (carticles (nnvirtual-partition-sequence articles)) | |
107 | (system-name (system-name)) | |
108 | cgroup carticle article result prefix) | |
109 | (while carticles | |
110 | (setq cgroup (caar carticles)) | |
111 | (setq articles (cdar carticles)) | |
112 | (pop carticles) | |
113 | (when (and articles | |
114 | (gnus-check-server | |
115 | (gnus-find-method-for-group cgroup) t) | |
116 | (gnus-request-group cgroup t) | |
117 | (setq prefix (gnus-group-real-prefix cgroup)) | |
118 | ;; FIX FIX FIX we want to check the cache! | |
119 | ;; This is probably evil if people have set | |
120 | ;; gnus-use-cache to nil themselves, but I | |
121 | ;; have no way of finding the true value of it. | |
122 | (let ((gnus-use-cache t)) | |
123 | (setq result (gnus-retrieve-headers | |
124 | articles cgroup nil)))) | |
125 | (set-buffer nntp-server-buffer) | |
126 | ;; If we got HEAD headers, we convert them into NOV | |
127 | ;; headers. This is slow, inefficient and, come to think | |
128 | ;; of it, downright evil. So sue me. I couldn't be | |
129 | ;; bothered to write a header parse routine that could | |
130 | ;; parse a mixed HEAD/NOV buffer. | |
131 | (when (eq result 'headers) | |
132 | (nnvirtual-convert-headers)) | |
133 | (goto-char (point-min)) | |
134 | (while (not (eobp)) | |
135 | (delete-region (point) | |
136 | (progn | |
137 | (setq carticle (read nntp-server-buffer)) | |
138 | (point))) | |
139 | ||
140 | ;; We remove this article from the articles list, if | |
141 | ;; anything is left in the articles list after going through | |
142 | ;; the entire buffer, then those articles have been | |
143 | ;; expired or canceled, so we appropriately update the | |
144 | ;; component group below. They should be coming up | |
145 | ;; generally in order, so this shouldn't be slow. | |
146 | (setq articles (delq carticle articles)) | |
147 | ||
148 | (setq article (nnvirtual-reverse-map-article cgroup carticle)) | |
149 | (if (null article) | |
150 | ;; This line has no reverse mapping, that means it | |
151 | ;; was an extra article reference returned by nntp. | |
152 | (progn | |
153 | (beginning-of-line) | |
154 | (delete-region (point) (progn (forward-line 1) (point)))) | |
155 | ;; Otherwise insert the virtual article number, | |
156 | ;; and clean up the xrefs. | |
157 | (princ article nntp-server-buffer) | |
158 | (nnvirtual-update-xref-header cgroup carticle | |
159 | prefix system-name) | |
160 | (forward-line 1)) | |
161 | ) | |
162 | ||
163 | (set-buffer vbuf) | |
164 | (goto-char (point-max)) | |
165 | (insert-buffer-substring nntp-server-buffer)) | |
166 | ;; Anything left in articles is expired or canceled. | |
167 | ;; Could be smart and not tell it about articles already known? | |
168 | (when articles | |
169 | (gnus-group-make-articles-read cgroup articles)) | |
170 | ) | |
171 | ||
172 | ;; The headers are ready for reading, so they are inserted into | |
173 | ;; the nntp-server-buffer, which is where Gnus expects to find | |
174 | ;; them. | |
175 | (prog1 | |
176 | (save-excursion | |
177 | (set-buffer nntp-server-buffer) | |
178 | (erase-buffer) | |
179 | (insert-buffer-substring vbuf) | |
180 | ;; FIX FIX FIX, we should be able to sort faster than | |
181 | ;; this if needed, since each cgroup is sorted, we just | |
182 | ;; need to merge | |
183 | (sort-numeric-fields 1 (point-min) (point-max)) | |
184 | 'nov) | |
185 | (kill-buffer vbuf))))))) | |
186 | ||
187 | ||
188 | (defvoo nnvirtual-last-accessed-component-group nil) | |
189 | ||
190 | (deffoo nnvirtual-request-article (article &optional group server buffer) | |
191 | (when (nnvirtual-possibly-change-server server) | |
192 | (if (stringp article) | |
193 | ;; This is a fetch by Message-ID. | |
194 | (cond | |
195 | ((not nnvirtual-last-accessed-component-group) | |
196 | (nnheader-report | |
197 | 'nnvirtual "Don't know what server to request from")) | |
198 | (t | |
199 | (save-excursion | |
200 | (when buffer | |
201 | (set-buffer buffer)) | |
202 | (let ((method (gnus-find-method-for-group | |
203 | nnvirtual-last-accessed-component-group))) | |
204 | (funcall (gnus-get-function method 'request-article) | |
205 | article nil (nth 1 method) buffer))))) | |
206 | ;; This is a fetch by number. | |
207 | (let* ((amap (nnvirtual-map-article article)) | |
208 | (cgroup (car amap))) | |
209 | (cond | |
210 | ((not amap) | |
211 | (nnheader-report 'nnvirtual "No such article: %s" article)) | |
212 | ((not (gnus-check-group cgroup)) | |
213 | (nnheader-report | |
214 | 'nnvirtual "Can't open server where %s exists" cgroup)) | |
215 | ((not (gnus-request-group cgroup t)) | |
216 | (nnheader-report 'nnvirtual "Can't open component group %s" cgroup)) | |
217 | (t | |
218 | (setq nnvirtual-last-accessed-component-group cgroup) | |
219 | (if buffer | |
220 | (save-excursion | |
221 | (set-buffer buffer) | |
222 | (gnus-request-article-this-buffer (cdr amap) cgroup)) | |
223 | (gnus-request-article (cdr amap) cgroup)))))))) | |
224 | ||
225 | ||
226 | (deffoo nnvirtual-open-server (server &optional defs) | |
227 | (unless (assq 'nnvirtual-component-regexp defs) | |
228 | (push `(nnvirtual-component-regexp ,server) | |
229 | defs)) | |
230 | (nnoo-change-server 'nnvirtual server defs) | |
231 | (if nnvirtual-component-groups | |
232 | t | |
233 | (setq nnvirtual-mapping-table nil | |
234 | nnvirtual-mapping-offsets nil | |
235 | nnvirtual-mapping-len 0 | |
236 | nnvirtual-mapping-reads nil | |
237 | nnvirtual-mapping-marks nil | |
238 | nnvirtual-info-installed nil) | |
239 | (when nnvirtual-component-regexp | |
240 | ;; Go through the newsrc alist and find all component groups. | |
241 | (let ((newsrc (cdr gnus-newsrc-alist)) | |
242 | group) | |
243 | (while (setq group (car (pop newsrc))) | |
244 | (when (string-match nnvirtual-component-regexp group) ; Match | |
245 | ;; Add this group to the list of component groups. | |
246 | (setq nnvirtual-component-groups | |
247 | (cons group (delete group nnvirtual-component-groups))))))) | |
248 | (if (not nnvirtual-component-groups) | |
249 | (nnheader-report 'nnvirtual "No component groups: %s" server) | |
250 | t))) | |
251 | ||
252 | ||
253 | (deffoo nnvirtual-request-group (group &optional server dont-check) | |
254 | (nnvirtual-possibly-change-server server) | |
255 | (setq nnvirtual-component-groups | |
256 | (delete (nnvirtual-current-group) nnvirtual-component-groups)) | |
257 | (cond | |
258 | ((null nnvirtual-component-groups) | |
259 | (setq nnvirtual-current-group nil) | |
260 | (nnheader-report 'nnvirtual "No component groups in %s" group)) | |
261 | (t | |
6748645f | 262 | (setq nnvirtual-current-group group) |
eec82323 LMI |
263 | (when (or (not dont-check) |
264 | nnvirtual-always-rescan) | |
6748645f LMI |
265 | (nnvirtual-create-mapping) |
266 | (when nnvirtual-always-rescan | |
267 | (nnvirtual-request-update-info | |
268 | (nnvirtual-current-group) | |
269 | (gnus-get-info (nnvirtual-current-group))))) | |
eec82323 LMI |
270 | (nnheader-insert "211 %d 1 %d %s\n" |
271 | nnvirtual-mapping-len nnvirtual-mapping-len group)))) | |
272 | ||
273 | ||
274 | (deffoo nnvirtual-request-type (group &optional article) | |
275 | (if (not article) | |
276 | 'unknown | |
6748645f LMI |
277 | (if (numberp article) |
278 | (let ((mart (nnvirtual-map-article article))) | |
279 | (if mart | |
280 | (gnus-request-type (car mart) (cdr mart)))) | |
281 | (gnus-request-type | |
282 | nnvirtual-last-accessed-component-group nil)))) | |
eec82323 LMI |
283 | |
284 | (deffoo nnvirtual-request-update-mark (group article mark) | |
285 | (let* ((nart (nnvirtual-map-article article)) | |
286 | (cgroup (car nart)) | |
287 | ;; The component group might be a virtual group. | |
288 | (nmark (gnus-request-update-mark cgroup (cdr nart) mark))) | |
289 | (when (and nart | |
290 | (= mark nmark) | |
291 | (gnus-group-auto-expirable-p cgroup)) | |
292 | (setq mark gnus-expirable-mark))) | |
293 | mark) | |
294 | ||
295 | ||
296 | (deffoo nnvirtual-close-group (group &optional server) | |
297 | (when (and (nnvirtual-possibly-change-server server) | |
298 | (not (gnus-ephemeral-group-p (nnvirtual-current-group)))) | |
299 | (nnvirtual-update-read-and-marked t t)) | |
300 | t) | |
301 | ||
302 | ||
303 | (deffoo nnvirtual-request-list (&optional server) | |
304 | (nnheader-report 'nnvirtual "LIST is not implemented.")) | |
305 | ||
306 | ||
307 | (deffoo nnvirtual-request-newgroups (date &optional server) | |
308 | (nnheader-report 'nnvirtual "NEWGROUPS is not supported.")) | |
309 | ||
310 | ||
311 | (deffoo nnvirtual-request-list-newsgroups (&optional server) | |
312 | (nnheader-report 'nnvirtual "LIST NEWSGROUPS is not implemented.")) | |
313 | ||
314 | ||
315 | (deffoo nnvirtual-request-update-info (group info &optional server) | |
316 | (when (and (nnvirtual-possibly-change-server server) | |
317 | (not nnvirtual-info-installed)) | |
318 | ;; Install the precomputed lists atomically, so the virtual group | |
319 | ;; is not left in a half-way state in case of C-g. | |
320 | (gnus-atomic-progn | |
321 | (setcar (cddr info) nnvirtual-mapping-reads) | |
322 | (if (nthcdr 3 info) | |
323 | (setcar (nthcdr 3 info) nnvirtual-mapping-marks) | |
324 | (when nnvirtual-mapping-marks | |
325 | (setcdr (nthcdr 2 info) (list nnvirtual-mapping-marks)))) | |
326 | (setq nnvirtual-info-installed t)) | |
327 | t)) | |
328 | ||
329 | ||
330 | (deffoo nnvirtual-catchup-group (group &optional server all) | |
331 | (when (and (nnvirtual-possibly-change-server server) | |
332 | (not (gnus-ephemeral-group-p (nnvirtual-current-group)))) | |
333 | ;; copy over existing marks first, in case they set anything | |
334 | (nnvirtual-update-read-and-marked nil nil) | |
335 | ;; do a catchup on all component groups | |
336 | (let ((gnus-group-marked (copy-sequence nnvirtual-component-groups)) | |
337 | (gnus-expert-user t)) | |
338 | ;; Make sure all groups are activated. | |
339 | (mapcar | |
340 | (lambda (g) | |
341 | (when (not (numberp (car (gnus-gethash g gnus-newsrc-hashtb)))) | |
342 | (gnus-activate-group g))) | |
343 | nnvirtual-component-groups) | |
344 | (save-excursion | |
345 | (set-buffer gnus-group-buffer) | |
346 | (gnus-group-catchup-current nil all))))) | |
347 | ||
348 | ||
349 | (deffoo nnvirtual-find-group-art (group article) | |
350 | "Return the real group and article for virtual GROUP and ARTICLE." | |
351 | (nnvirtual-map-article article)) | |
352 | ||
6748645f LMI |
353 | |
354 | (deffoo nnvirtual-request-post (&optional server) | |
355 | (if (not gnus-message-group-art) | |
356 | (nnheader-report 'nnvirtual "Can't post to an nnvirtual group") | |
357 | (let ((group (car (nnvirtual-find-group-art | |
358 | (car gnus-message-group-art) | |
359 | (cdr gnus-message-group-art))))) | |
360 | (gnus-request-post (gnus-find-method-for-group group))))) | |
361 | ||
eec82323 LMI |
362 | \f |
363 | ;;; Internal functions. | |
364 | ||
365 | (defun nnvirtual-convert-headers () | |
366 | "Convert HEAD headers into NOV headers." | |
367 | (save-excursion | |
368 | (set-buffer nntp-server-buffer) | |
369 | (let* ((dependencies (make-vector 100 0)) | |
370 | (headers (gnus-get-newsgroup-headers dependencies)) | |
371 | header) | |
372 | (erase-buffer) | |
373 | (while (setq header (pop headers)) | |
374 | (nnheader-insert-nov header))))) | |
375 | ||
376 | ||
377 | (defun nnvirtual-update-xref-header (group article prefix system-name) | |
378 | "Edit current NOV header in current buffer to have an xref to the component group, and also server prefix any existing xref lines." | |
379 | ;; Move to beginning of Xref field, creating a slot if needed. | |
380 | (beginning-of-line) | |
381 | (looking-at | |
382 | "[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t") | |
383 | (goto-char (match-end 0)) | |
384 | (unless (search-forward "\t" (gnus-point-at-eol) 'move) | |
385 | (insert "\t")) | |
386 | ||
387 | ;; Remove any spaces at the beginning of the Xref field. | |
388 | (while (= (char-after (1- (point))) ? ) | |
389 | (forward-char -1) | |
390 | (delete-char 1)) | |
391 | ||
392 | (insert "Xref: " system-name " " group ":") | |
393 | (princ article (current-buffer)) | |
a8151ef7 | 394 | (insert " ") |
eec82323 LMI |
395 | |
396 | ;; If there were existing xref lines, clean them up to have the correct | |
397 | ;; component server prefix. | |
a8151ef7 LMI |
398 | (save-restriction |
399 | (narrow-to-region (point) | |
400 | (or (search-forward "\t" (gnus-point-at-eol) t) | |
401 | (gnus-point-at-eol))) | |
402 | (goto-char (point-min)) | |
403 | (when (re-search-forward "Xref: *[^\n:0-9 ]+ *" nil t) | |
404 | (replace-match "" t t)) | |
405 | (goto-char (point-min)) | |
406 | (when (re-search-forward | |
6748645f | 407 | (concat (regexp-quote (gnus-group-real-name group)) ":[0-9]+") |
a8151ef7 LMI |
408 | nil t) |
409 | (replace-match "" t t)) | |
410 | (unless (= (point) (point-max)) | |
eec82323 LMI |
411 | (insert " ") |
412 | (when (not (string= "" prefix)) | |
a8151ef7 | 413 | (while (re-search-forward "[^ ]+:[0-9]+" nil t) |
eec82323 LMI |
414 | (save-excursion |
415 | (goto-char (match-beginning 0)) | |
a8151ef7 | 416 | (insert prefix)))))) |
eec82323 LMI |
417 | |
418 | ;; Ensure a trailing \t. | |
419 | (end-of-line) | |
420 | (or (= (char-after (1- (point))) ?\t) | |
421 | (insert ?\t))) | |
422 | ||
423 | ||
424 | (defun nnvirtual-possibly-change-server (server) | |
425 | (or (not server) | |
426 | (nnoo-current-server-p 'nnvirtual server) | |
427 | (nnvirtual-open-server server))) | |
428 | ||
429 | ||
430 | (defun nnvirtual-update-read-and-marked (read-p update-p) | |
431 | "Copy marks from the virtual group to the component groups. | |
432 | If READ-P is not nil, update the (un)read status of the components. | |
433 | If UPDATE-P is not nil, call gnus-group-update-group on the components." | |
434 | (when nnvirtual-current-group | |
435 | (let ((unreads (and read-p | |
436 | (nnvirtual-partition-sequence | |
437 | (gnus-list-of-unread-articles | |
438 | (nnvirtual-current-group))))) | |
439 | (type-marks (mapcar (lambda (ml) | |
440 | (cons (car ml) | |
441 | (nnvirtual-partition-sequence (cdr ml)))) | |
442 | (gnus-info-marks (gnus-get-info | |
443 | (nnvirtual-current-group))))) | |
444 | mark type groups carticles info entry) | |
445 | ||
446 | ;; Ok, atomically move all of the (un)read info, clear any old | |
447 | ;; marks, and move all of the current marks. This way if someone | |
448 | ;; hits C-g, you won't leave the component groups in a half-way state. | |
449 | (gnus-atomic-progn | |
450 | ;; move (un)read | |
451 | (let ((gnus-newsgroup-active nil)) ;workaround guns-update-read-articles | |
452 | (while (setq entry (pop unreads)) | |
453 | (gnus-update-read-articles (car entry) (cdr entry)))) | |
454 | ||
455 | ;; clear all existing marks on the component groups | |
456 | (setq groups nnvirtual-component-groups) | |
457 | (while groups | |
458 | (when (and (setq info (gnus-get-info (pop groups))) | |
459 | (gnus-info-marks info)) | |
460 | (gnus-info-set-marks info nil))) | |
461 | ||
462 | ;; Ok, currently type-marks is an assq list with keys of a mark type, | |
463 | ;; with data of an assq list with keys of component group names | |
464 | ;; and the articles which correspond to that key/group pair. | |
465 | (while (setq mark (pop type-marks)) | |
466 | (setq type (car mark)) | |
467 | (setq groups (cdr mark)) | |
468 | (while (setq carticles (pop groups)) | |
469 | (gnus-add-marked-articles (car carticles) type (cdr carticles) | |
470 | nil t)))) | |
471 | ||
472 | ;; possibly update the display, it is really slow | |
473 | (when update-p | |
474 | (setq groups nnvirtual-component-groups) | |
475 | (while groups | |
476 | (gnus-group-update-group (pop groups) t)))))) | |
477 | ||
478 | ||
479 | (defun nnvirtual-current-group () | |
480 | "Return the prefixed name of the current nnvirtual group." | |
481 | (concat "nnvirtual:" nnvirtual-current-group)) | |
482 | ||
483 | ||
484 | ||
485 | ;;; This is currently O(kn^2) to merge n lists of length k. | |
486 | ;;; You could do it in O(knlogn), but we have a small n, and the | |
487 | ;;; overhead of the other approach is probably greater. | |
488 | (defun nnvirtual-merge-sorted-lists (&rest lists) | |
489 | "Merge many sorted lists of numbers." | |
490 | (if (null (cdr lists)) | |
491 | (car lists) | |
ef3eaa35 | 492 | (sort (apply 'nconc lists) '<))) |
eec82323 LMI |
493 | |
494 | ||
495 | ;;; We map between virtual articles and real articles in a manner | |
496 | ;;; which keeps the size of the virtual active list the same as | |
497 | ;;; the sum of the component active lists. | |
498 | ;;; To achieve fair mixing of the groups, the last article in | |
499 | ;;; each of N component groups will be in the the last N articles | |
500 | ;;; in the virtual group. | |
501 | ||
502 | ;;; If you have 3 components A, B and C, with articles 1-8, 1-5, and 6-7 | |
503 | ;;; resprectively, then the virtual article numbers look like: | |
504 | ;;; | |
505 | ;;; 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | |
506 | ;;; A1 A2 A3 A4 B1 A5 B2 A6 B3 A7 B4 C6 A8 B5 C7 | |
507 | ||
508 | ;;; To compute these mappings we generate a couple tables and then | |
509 | ;;; do some fast operations on them. Tables for the example above: | |
510 | ;;; | |
511 | ;;; Offsets - [(A 0) (B -3) (C -1)] | |
512 | ;;; | |
513 | ;;; a b c d e | |
514 | ;;; Mapping - ([ 3 0 1 3 0 ] | |
515 | ;;; [ 6 3 2 9 3 ] | |
516 | ;;; [ 8 6 3 15 9 ]) | |
517 | ;;; | |
518 | ;;; (note column 'e' is different in real algorithm, which is slightly | |
519 | ;;; different than described here, but this gives you the methodology.) | |
520 | ;;; | |
521 | ;;; The basic idea is this, when going from component->virtual, apply | |
522 | ;;; the appropriate offset to the article number. Then search the first | |
523 | ;;; column of the table for a row where 'a' is less than or equal to the | |
524 | ;;; modified number. You can see that only group A can therefore go to | |
525 | ;;; the first row, groups A and B to the second, and all to the last. | |
526 | ;;; The third column of the table is telling us the number of groups | |
527 | ;;; which might be able to reach that row (it might increase by more than | |
528 | ;;; 1 if several groups have the same size). | |
529 | ;;; Then column 'b' provides an additional offset you apply when you have | |
530 | ;;; found the correct row. You then multiply by 'c' and add on the groups | |
531 | ;;; _position_ in the offset table. The basic idea here is that on | |
532 | ;;; any given row we are going to map back and forth using X'=X*c+Y and | |
533 | ;;; X=(X'/c), Y=(X' mod c). Then once you've done this transformation, | |
534 | ;;; you apply a final offset from column 'e' to give the virtual article. | |
535 | ;;; | |
536 | ;;; Going the other direction, you instead search on column 'd' instead | |
537 | ;;; of 'a', and apply everything in reverse order. | |
538 | ||
539 | ;;; Convert component -> virtual: | |
540 | ;;; set num = num - Offset(group) | |
541 | ;;; find first row in Mapping where num <= 'a' | |
542 | ;;; num = (num-'b')*c + Position(group) + 'e' | |
543 | ||
544 | ;;; Convert virtual -> component: | |
545 | ;;; find first row in Mapping where num <= 'd' | |
546 | ;;; num = num - 'e' | |
547 | ;;; group_pos = num mod 'c' | |
548 | ;;; num = (num / 'c') + 'b' + Offset(group_pos) | |
549 | ||
550 | ;;; Easy no? :) | |
551 | ;;; | |
552 | ;;; Well actually, you need to keep column e offset smaller by the 'c' | |
553 | ;;; column for that line, and always add 1 more when going from | |
554 | ;;; component -> virtual. Otherwise you run into a problem with | |
555 | ;;; unique reverse mapping. | |
556 | ||
557 | (defun nnvirtual-map-article (article) | |
558 | "Return a cons of the component group and article corresponding to the given virtual ARTICLE." | |
559 | (let ((table nnvirtual-mapping-table) | |
560 | entry group-pos) | |
561 | (while (and table | |
562 | (> article (aref (car table) 3))) | |
563 | (setq table (cdr table))) | |
564 | (when (and table | |
565 | (> article 0)) | |
566 | (setq entry (car table)) | |
567 | (setq article (- article (aref entry 4) 1)) | |
568 | (setq group-pos (mod article (aref entry 2))) | |
569 | (cons (car (aref nnvirtual-mapping-offsets group-pos)) | |
570 | (+ (/ article (aref entry 2)) | |
571 | (aref entry 1) | |
572 | (cdr (aref nnvirtual-mapping-offsets group-pos))) | |
573 | )) | |
574 | )) | |
575 | ||
576 | ||
577 | ||
578 | (defun nnvirtual-reverse-map-article (group article) | |
579 | "Return the virtual article number corresponding to the given component GROUP and ARTICLE." | |
6748645f LMI |
580 | (when (numberp article) |
581 | (let ((table nnvirtual-mapping-table) | |
582 | (group-pos 0) | |
583 | entry) | |
584 | (while (not (string= group (car (aref nnvirtual-mapping-offsets | |
585 | group-pos)))) | |
586 | (setq group-pos (1+ group-pos))) | |
587 | (setq article (- article (cdr (aref nnvirtual-mapping-offsets | |
eec82323 | 588 | group-pos)))) |
6748645f LMI |
589 | (while (and table |
590 | (> article (aref (car table) 0))) | |
591 | (setq table (cdr table))) | |
592 | (setq entry (car table)) | |
593 | (when (and entry | |
594 | (> article 0) | |
595 | (< group-pos (aref entry 2))) ; article not out of range below | |
596 | (+ (aref entry 4) | |
597 | group-pos | |
598 | (* (- article (aref entry 1)) | |
599 | (aref entry 2)) | |
600 | 1)) | |
601 | ))) | |
eec82323 LMI |
602 | |
603 | ||
604 | (defsubst nnvirtual-reverse-map-sequence (group articles) | |
605 | "Return list of virtual article numbers for all ARTICLES in GROUP. | |
606 | The ARTICLES should be sorted, and can be a compressed sequence. | |
607 | If any of the article numbers has no corresponding virtual article, | |
608 | then it is left out of the result." | |
609 | (when (numberp (cdr-safe articles)) | |
610 | (setq articles (list articles))) | |
611 | (let (result a i j new-a) | |
612 | (while (setq a (pop articles)) | |
613 | (if (atom a) | |
614 | (setq i a | |
615 | j a) | |
616 | (setq i (car a) | |
617 | j (cdr a))) | |
618 | (while (<= i j) | |
619 | ;; If this is slow, you can optimize by moving article checking | |
620 | ;; into here. You don't have to recompute the group-pos, | |
621 | ;; nor scan the table every time. | |
622 | (when (setq new-a (nnvirtual-reverse-map-article group i)) | |
623 | (push new-a result)) | |
624 | (setq i (1+ i)))) | |
625 | (nreverse result))) | |
626 | ||
627 | ||
628 | (defun nnvirtual-partition-sequence (articles) | |
629 | "Return an association list of component article numbers. | |
630 | These are indexed by elements of nnvirtual-component-groups, based on | |
631 | the sequence ARTICLES of virtual article numbers. ARTICLES should be | |
632 | sorted, and can be a compressed sequence. If any of the article | |
633 | numbers has no corresponding component article, then it is left out of | |
634 | the result." | |
635 | (when (numberp (cdr-safe articles)) | |
636 | (setq articles (list articles))) | |
637 | (let ((carticles (mapcar (lambda (g) (list g)) | |
638 | nnvirtual-component-groups)) | |
639 | a i j article entry) | |
640 | (while (setq a (pop articles)) | |
641 | (if (atom a) | |
642 | (setq i a | |
643 | j a) | |
644 | (setq i (car a) | |
645 | j (cdr a))) | |
646 | (while (<= i j) | |
647 | (when (setq article (nnvirtual-map-article i)) | |
648 | (setq entry (assoc (car article) carticles)) | |
649 | (setcdr entry (cons (cdr article) (cdr entry)))) | |
650 | (setq i (1+ i)))) | |
ef3eaa35 RS |
651 | (mapcar (lambda (x) (setcdr x (nreverse (cdr x)))) |
652 | carticles) | |
eec82323 LMI |
653 | carticles)) |
654 | ||
655 | ||
656 | (defun nnvirtual-create-mapping () | |
657 | "Build the tables necessary to map between component (group, article) to virtual article. | |
658 | Generate the set of read messages and marks for the virtual group | |
659 | based on the marks on the component groups." | |
660 | (let ((cnt 0) | |
661 | (tot 0) | |
662 | (M 0) | |
663 | (i 0) | |
664 | actives all-unreads all-marks | |
665 | active min max size unreads marks | |
666 | next-M next-tot | |
667 | reads beg) | |
668 | ;; Ok, we loop over all component groups and collect a lot of | |
669 | ;; information: | |
670 | ;; Into actives we place (g size max), where size is max-min+1. | |
671 | ;; Into all-unreads we put (g unreads). | |
672 | ;; Into all-marks we put (g marks). | |
673 | ;; We also increment cnt and tot here, and compute M (max of sizes). | |
54b02948 DL |
674 | (mapcar (lambda (g) |
675 | (setq active (gnus-activate-group g) | |
676 | min (car active) | |
677 | max (cdr active)) | |
678 | (when (and active (>= max min) (not (zerop max))) | |
679 | ;; store active information | |
680 | (push (list g (- max min -1) max) actives) | |
681 | ;; collect unread/mark info for later | |
682 | (setq unreads (gnus-list-of-unread-articles g)) | |
683 | (setq marks (gnus-info-marks (gnus-get-info g))) | |
684 | (when gnus-use-cache | |
685 | (push (cons 'cache | |
686 | (gnus-cache-articles-in-group g)) | |
687 | marks)) | |
688 | (push (cons g unreads) all-unreads) | |
689 | (push (cons g marks) all-marks) | |
690 | ;; count groups, total #articles, and max size | |
691 | (setq size (- max min -1)) | |
692 | (setq cnt (1+ cnt) | |
693 | tot (+ tot size) | |
694 | M (max M size)))) | |
eec82323 LMI |
695 | nnvirtual-component-groups) |
696 | ||
697 | ;; Number of articles in the virtual group. | |
698 | (setq nnvirtual-mapping-len tot) | |
699 | ||
700 | ||
701 | ;; We want the actives list sorted by size, to build the tables. | |
702 | (setq actives (sort actives (lambda (g1 g2) (< (nth 1 g1) (nth 1 g2))))) | |
703 | ||
704 | ;; Build the offset table. Largest sized groups are at the front. | |
705 | (setq nnvirtual-mapping-offsets | |
706 | (vconcat | |
707 | (nreverse | |
708 | (mapcar (lambda (entry) | |
709 | (cons (nth 0 entry) | |
710 | (- (nth 2 entry) M))) | |
711 | actives)))) | |
712 | ||
713 | ;; Build the mapping table. | |
714 | (setq nnvirtual-mapping-table nil) | |
715 | (setq actives (mapcar (lambda (entry) (nth 1 entry)) actives)) | |
716 | (while actives | |
717 | (setq size (car actives)) | |
718 | (setq next-M (- M size)) | |
719 | (setq next-tot (- tot (* cnt size))) | |
720 | ;; make current row in table | |
721 | (push (vector M next-M cnt tot (- next-tot cnt)) | |
722 | nnvirtual-mapping-table) | |
723 | ;; update M and tot | |
724 | (setq M next-M) | |
725 | (setq tot next-tot) | |
726 | ;; subtract the current size from all entries. | |
727 | (setq actives (mapcar (lambda (x) (- x size)) actives)) | |
728 | ;; remove anything that went to 0. | |
729 | (while (and actives | |
730 | (= (car actives) 0)) | |
731 | (pop actives) | |
732 | (setq cnt (- cnt 1)))) | |
733 | ||
734 | ||
735 | ;; Now that the mapping tables are generated, we can convert | |
736 | ;; and combine the separate component unreads and marks lists | |
737 | ;; into single lists of virtual article numbers. | |
738 | (setq unreads (apply 'nnvirtual-merge-sorted-lists | |
739 | (mapcar (lambda (x) | |
740 | (nnvirtual-reverse-map-sequence | |
741 | (car x) (cdr x))) | |
742 | all-unreads))) | |
743 | (setq marks (mapcar | |
744 | (lambda (type) | |
745 | (cons (cdr type) | |
746 | (gnus-compress-sequence | |
747 | (apply | |
748 | 'nnvirtual-merge-sorted-lists | |
749 | (mapcar (lambda (x) | |
750 | (nnvirtual-reverse-map-sequence | |
751 | (car x) | |
752 | (cdr (assq (cdr type) (cdr x))))) | |
753 | all-marks))))) | |
754 | gnus-article-mark-lists)) | |
755 | ||
756 | ;; Remove any empty marks lists, and store. | |
ef3eaa35 RS |
757 | (setq nnvirtual-mapping-marks nil) |
758 | (while marks | |
759 | (if (cdr (car marks)) | |
760 | (push (car marks) nnvirtual-mapping-marks)) | |
761 | (setq marks (cdr marks))) | |
eec82323 LMI |
762 | |
763 | ;; We need to convert the unreads to reads. We compress the | |
764 | ;; sequence as we go, otherwise it could be huge. | |
765 | (while (and (<= (incf i) nnvirtual-mapping-len) | |
766 | unreads) | |
767 | (if (= i (car unreads)) | |
768 | (setq unreads (cdr unreads)) | |
769 | ;; try to get a range. | |
770 | (setq beg i) | |
771 | (while (and (<= (incf i) nnvirtual-mapping-len) | |
772 | (not (= i (car unreads))))) | |
773 | (setq i (- i 1)) | |
774 | (if (= i beg) | |
775 | (push i reads) | |
776 | (push (cons beg i) reads)) | |
777 | )) | |
778 | (when (<= i nnvirtual-mapping-len) | |
779 | (if (= i nnvirtual-mapping-len) | |
780 | (push i reads) | |
781 | (push (cons i nnvirtual-mapping-len) reads))) | |
782 | ||
783 | ;; Store the reads list for later use. | |
784 | (setq nnvirtual-mapping-reads (nreverse reads)) | |
785 | ||
786 | ;; Throw flag to show we changed the info. | |
787 | (setq nnvirtual-info-installed nil) | |
788 | )) | |
789 | ||
790 | (provide 'nnvirtual) | |
791 | ||
792 | ;;; nnvirtual.el ends here |