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