lisp/gnus/gnus-cite.el

   1 ;;; gnus-cite.el --- parse citations in articles for Gnus
   2
   3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   4 ;;   2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   5
   6 ;; Author: Per Abhiddenware
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 (eval-when-compile (require 'cl))
  28 (eval-when-compile
  29   (when (featurep 'xemacs)
  30     (require 'easy-mmode))) ; for `define-minor-mode'
  31
  32 (require 'gnus)
  33 (require 'gnus-range)
  34 (require 'gnus-art)
  35 (require 'message)      ; for message-cite-prefix-regexp
  36
  37 ;;; Customization:
  38
  39 (defgroup gnus-cite nil
  40   "Citation."
  41   :prefix "gnus-cite-"
  42   :link '(custom-manual "(gnus)Article Highlighting")
  43   :group 'gnus-article)
  44
  45 (defcustom gnus-cited-opened-text-button-line-format "%(%{[-]%}%)\n"
  46   "Format of opened cited text buttons."
  47   :group 'gnus-cite
  48   :type 'string)
  49
  50 (defcustom gnus-cited-closed-text-button-line-format "%(%{[+]%}%)\n"
  51   "Format of closed cited text buttons."
  52   :group 'gnus-cite
  53   :type 'string)
  54
  55 (defcustom gnus-cited-lines-visible nil
  56   "The number of lines of hidden cited text to remain visible.
  57 Or a pair (cons) of numbers which are the number of lines at the top
  58 and bottom of the text, respectively, to remain visible."
  59   :group 'gnus-cite
  60   :type '(choice (const :tag "none" nil)
  61                  integer
  62                  (cons :tag "Top and Bottom" integer integer)))
  63
  64 (defcustom gnus-cite-parse-max-size 25000
  65   "Maximum article size (in bytes) where parsing citations is allowed.
  66 Set it to nil to parse all articles."
  67   :group 'gnus-cite
  68   :type '(choice (const :tag "all" nil)
  69                  integer))
  70
  71 (defcustom gnus-cite-max-prefix 20
  72   "Maximum possible length for a citation prefix."
  73   :group 'gnus-cite
  74   :type 'integer)
  75
  76 (defcustom gnus-supercite-regexp
  77   (concat "^\\(" message-cite-prefix-regexp "\\)? *"
  78           ">>>>> +\"\\([^\"\n]+\\)\" +==")
  79   "*Regexp matching normal Supercite attribution lines.
  80 The first grouping must match prefixes added by other packages."
  81   :group 'gnus-cite
  82   :type 'regexp)
  83
  84 (defcustom gnus-supercite-secondary-regexp "^.*\"\\([^\"\n]+\\)\" +=="
  85   "Regexp matching mangled Supercite attribution lines.
  86 The first regexp group should match the Supercite attribution."
  87   :group 'gnus-cite
  88   :type 'regexp)
  89
  90 (defcustom gnus-cite-minimum-match-count 2
  91   "Minimum number of identical prefixes before we believe it's a citation."
  92   :group 'gnus-cite
  93   :type 'integer)
  94
  95 ;; Some Microsoft products put in a citation that extends to the
  96 ;; remainder of the message:
  97 ;;
  98 ;;     -----Original Message-----
  99 ;;     From: ...
 100 ;;     To: ...
 101 ;;     Sent: ...   [date, in non-RFC-2822 format]
 102 ;;     Subject: ...
 103 ;;
 104 ;;     Cited message, with no prefixes
 105 ;;
 106 ;; The four headers are always the same.  But note they are prone to
 107 ;; folding without additional indentation.
 108 ;;
 109 ;; Others use "----- Original Message -----" instead, and properly quote
 110 ;; the body using "> ".  This style is handled without special cases.
 111
 112 (defcustom gnus-cite-attribution-prefix
 113   "In article\\|in <\\|On \\(Mon\\|Tue\\|Wed\\|Thu\\|Fri\\|Sat\\|Sun\\),\\|----- ?Original Message ?-----"
 114   "*Regexp matching the beginning of an attribution line."
 115   :group 'gnus-cite
 116   :type 'regexp)
 117
 118 (defcustom gnus-cite-attribution-suffix
 119   "\\(\\(wrote\\|writes\\|said\\|says\\|>\\)\\(:\\|\\.\\.\\.\\)\\|----- ?Original Message ?-----\\)[ \t]*$"
 120   "*Regexp matching the end of an attribution line.
 121 The text matching the first grouping will be used as a button."
 122   :group 'gnus-cite
 123   :type 'regexp)
 124
 125 (defcustom gnus-cite-unsightly-citation-regexp
 126   "^-----Original Message-----\nFrom: \\(.+\n\\)+\n"
 127   "Regexp matching Microsoft-type rest-of-message citations."
 128   :version "22.1"
 129   :group 'gnus-cite
 130   :type 'regexp)
 131
 132 (defcustom gnus-cite-ignore-quoted-from t
 133   "Non-nil means don't regard lines beginning with \">From \" as cited text.
 134 Those lines may have been quoted by MTAs in order not to mix up with
 135 the envelope From line."
 136   :version "22.1"
 137   :group 'gnus-cite
 138   :type 'boolean)
 139
 140 (defface gnus-cite-attribution '((t (:italic t)))
 141   "Face used for attribution lines."
 142   :group 'gnus-cite)
 143 ;; backward-compatibility alias
 144 (put 'gnus-cite-attribution-face 'face-alias 'gnus-cite-attribution)
 145 (put 'gnus-cite-attribution-face 'obsolete-face "22.1")
 146
 147 (defcustom gnus-cite-attribution-face 'gnus-cite-attribution
 148   "Face used for attribution lines.
 149 It is merged with the face for the cited text belonging to the attribution."
 150   :version "22.1"
 151   :group 'gnus-cite
 152   :type 'face)
 153
 154 (defface gnus-cite-1 '((((class color)
 155                          (background dark))
 156                         (:foreground "light blue"))
 157                        (((class color)
 158                          (background light))
 159                         (:foreground "MidnightBlue"))
 160                        (t
 161                         (:italic t)))
 162   "Citation face."
 163   :group 'gnus-cite)
 164 ;; backward-compatibility alias
 165 (put 'gnus-cite-face-1 'face-alias 'gnus-cite-1)
 166 (put 'gnus-cite-face-1 'obsolete-face "22.1")
 167
 168 (defface gnus-cite-2 '((((class color)
 169                          (background dark))
 170                         (:foreground "light cyan"))
 171                        (((class color)
 172                          (background light))
 173                         (:foreground "firebrick"))
 174                        (t
 175                         (:italic t)))
 176   "Citation face."
 177   :group 'gnus-cite)
 178 ;; backward-compatibility alias
 179 (put 'gnus-cite-face-2 'face-alias 'gnus-cite-2)
 180 (put 'gnus-cite-face-2 'obsolete-face "22.1")
 181
 182 (defface gnus-cite-3 '((((class color)
 183                          (background dark))
 184                         (:foreground "light yellow"))
 185                        (((class color)
 186                          (background light))
 187                         (:foreground "dark green"))
 188                        (t
 189                         (:italic t)))
 190   "Citation face."
 191   :group 'gnus-cite)
 192 ;; backward-compatibility alias
 193 (put 'gnus-cite-face-3 'face-alias 'gnus-cite-3)
 194 (put 'gnus-cite-face-3 'obsolete-face "22.1")
 195
 196 (defface gnus-cite-4 '((((class color)
 197                          (background dark))
 198                         (:foreground "light pink"))
 199                        (((class color)
 200                          (background light))
 201                         (:foreground "OrangeRed"))
 202                        (t
 203                         (:italic t)))
 204   "Citation face."
 205   :group 'gnus-cite)
 206 ;; backward-compatibility alias
 207 (put 'gnus-cite-face-4 'face-alias 'gnus-cite-4)
 208 (put 'gnus-cite-face-4 'obsolete-face "22.1")
 209
 210 (defface gnus-cite-5 '((((class color)
 211                          (background dark))
 212                         (:foreground "pale green"))
 213                        (((class color)
 214                          (background light))
 215                         (:foreground "dark khaki"))
 216                        (t
 217                         (:italic t)))
 218   "Citation face."
 219   :group 'gnus-cite)
 220 ;; backward-compatibility alias
 221 (put 'gnus-cite-face-5 'face-alias 'gnus-cite-5)
 222 (put 'gnus-cite-face-5 'obsolete-face "22.1")
 223
 224 (defface gnus-cite-6 '((((class color)
 225                          (background dark))
 226                         (:foreground "beige"))
 227                        (((class color)
 228                          (background light))
 229                         (:foreground "dark violet"))
 230                        (t
 231                         (:italic t)))
 232   "Citation face."
 233   :group 'gnus-cite)
 234 ;; backward-compatibility alias
 235 (put 'gnus-cite-face-6 'face-alias 'gnus-cite-6)
 236 (put 'gnus-cite-face-6 'obsolete-face "22.1")
 237
 238 (defface gnus-cite-7 '((((class color)
 239                          (background dark))
 240                         (:foreground "orange"))
 241                        (((class color)
 242                          (background light))
 243                         (:foreground "SteelBlue4"))
 244                        (t
 245                         (:italic t)))
 246   "Citation face."
 247   :group 'gnus-cite)
 248 ;; backward-compatibility alias
 249 (put 'gnus-cite-face-7 'face-alias 'gnus-cite-7)
 250 (put 'gnus-cite-face-7 'obsolete-face "22.1")
 251
 252 (defface gnus-cite-8 '((((class color)
 253                          (background dark))
 254                         (:foreground "magenta"))
 255                        (((class color)
 256                          (background light))
 257                         (:foreground "magenta"))
 258                        (t
 259                         (:italic t)))
 260   "Citation face."
 261   :group 'gnus-cite)
 262 ;; backward-compatibility alias
 263 (put 'gnus-cite-face-8 'face-alias 'gnus-cite-8)
 264 (put 'gnus-cite-face-8 'obsolete-face "22.1")
 265
 266 (defface gnus-cite-9 '((((class color)
 267                          (background dark))
 268                         (:foreground "violet"))
 269                        (((class color)
 270                          (background light))
 271                         (:foreground "violet"))
 272                        (t
 273                         (:italic t)))
 274   "Citation face."
 275   :group 'gnus-cite)
 276 ;; backward-compatibility alias
 277 (put 'gnus-cite-face-9 'face-alias 'gnus-cite-9)
 278 (put 'gnus-cite-face-9 'obsolete-face "22.1")
 279
 280 (defface gnus-cite-10 '((((class color)
 281                           (background dark))
 282                          (:foreground "plum1"))
 283                         (((class color)
 284                           (background light))
 285                          (:foreground "medium purple"))
 286                         (t
 287                          (:italic t)))
 288   "Citation face."
 289   :group 'gnus-cite)
 290 ;; backward-compatibility alias
 291 (put 'gnus-cite-face-10 'face-alias 'gnus-cite-10)
 292 (put 'gnus-cite-face-10 'obsolete-face "22.1")
 293
 294 (defface gnus-cite-11 '((((class color)
 295                           (background dark))
 296                          (:foreground "turquoise"))
 297                         (((class color)
 298                           (background light))
 299                          (:foreground "turquoise"))
 300                         (t
 301                          (:italic t)))
 302   "Citation face."
 303   :group 'gnus-cite)
 304 ;; backward-compatibility alias
 305 (put 'gnus-cite-face-11 'face-alias 'gnus-cite-11)
 306 (put 'gnus-cite-face-11 'obsolete-face "22.1")
 307
 308 (defcustom gnus-cite-face-list
 309   '(gnus-cite-1 gnus-cite-2 gnus-cite-3 gnus-cite-4 gnus-cite-5 gnus-cite-6
 310                 gnus-cite-7 gnus-cite-8 gnus-cite-9 gnus-cite-10 gnus-cite-11)
 311   "*List of faces used for highlighting citations.
 312
 313 When there are citations from multiple articles in the same message,
 314 Gnus will try to give each citation from each article its own face.
 315 This should make it easier to see who wrote what."
 316   :group 'gnus-cite
 317   :type '(repeat face)
 318   :set (lambda (symbol value)
 319          (prog1
 320              (custom-set-default symbol value)
 321            (if (boundp 'gnus-message-max-citation-depth)
 322                (setq gnus-message-max-citation-depth (length value)))
 323            (if (boundp 'gnus-message-citation-keywords)
 324                (setq gnus-message-citation-keywords
 325                      `((gnus-message-search-citation-line
 326                         ,@(let ((list nil)
 327                                 (count 1))
 328                             (dolist (face value (nreverse list))
 329                               (push (list count (list 'quote face) 'prepend t)
 330                                     list)
 331                               (setq count (1+ count)))))))))))
 332
 333 (defcustom gnus-cite-hide-percentage 50
 334   "Only hide excess citation if above this percentage of the body."
 335   :group 'gnus-cite
 336   :type 'number)
 337
 338 (defcustom gnus-cite-hide-absolute 10
 339   "Only hide excess citation if above this number of lines in the body."
 340   :group 'gnus-cite
 341   :type 'integer)
 342
 343 (defcustom gnus-cite-blank-line-after-header t
 344   "If non-nil, put a blank line between the citation header and the button."
 345   :group 'gnus-cite
 346   :type 'boolean)
 347
 348 ;; This has to go here because its default value depends on
 349 ;; gnus-cite-face-list.
 350 (defcustom gnus-article-boring-faces (cons 'gnus-signature gnus-cite-face-list)
 351   "List of faces that are not worth reading.
 352 If an article has more pages below the one you are looking at, but
 353 nothing on those pages is a word of at least three letters that is not
 354 in a boring face, then the pages will be skipped."
 355   :type '(repeat face)
 356   :group 'gnus-article-hiding)
 357
 358 ;;; Internal Variables:
 359
 360 (defvar gnus-cite-article nil)
 361 (defvar gnus-cite-overlay-list nil)
 362
 363 (defvar gnus-cite-prefix-alist nil)
 364 ;; Alist of citation prefixes.
 365 ;; The cdr is a list of lines with that prefix.
 366
 367 (defvar gnus-cite-attribution-alist nil)
 368 ;; Alist of attribution lines.
 369 ;; The car is a line number.
 370 ;; The cdr is the prefix for the citation started by that line.
 371
 372 (defvar gnus-cite-loose-prefix-alist nil)
 373 ;; Alist of citation prefixes that have no matching attribution.
 374 ;; The cdr is a list of lines with that prefix.
 375
 376 (defvar gnus-cite-loose-attribution-alist nil)
 377 ;; Alist of attribution lines that have no matching citation.
 378 ;; Each member has the form (WROTE IN PREFIX TAG), where
 379 ;; WROTE: is the attribution line number
 380 ;; IN: is the line number of the previous line if part of the same attribution,
 381 ;; PREFIX: Is the citation prefix of the attribution line(s), and
 382 ;; TAG: Is a Supercite tag, if any.
 383
 384 (defvar gnus-cited-opened-text-button-line-format-alist
 385   `((?b (marker-position beg) ?d)
 386     (?e (marker-position end) ?d)
 387     (?n (count-lines beg end) ?d)
 388     (?l (- end beg) ?d)))
 389 (defvar gnus-cited-opened-text-button-line-format-spec nil)
 390 (defvar gnus-cited-closed-text-button-line-format-alist
 391   gnus-cited-opened-text-button-line-format-alist)
 392 (defvar gnus-cited-closed-text-button-line-format-spec nil)
 393
 394
 395 ;;; Commands:
 396
 397 (defun gnus-article-highlight-citation (&optional force same-buffer)
 398   "Highlight cited text.
 399 Each citation in the article will be highlighted with a different face.
 400 The faces are taken from `gnus-cite-face-list'.
 401 Attribution lines are highlighted with the same face as the
 402 corresponding citation merged with the face `gnus-cite-attribution'.
 403
 404 Text is considered cited if at least `gnus-cite-minimum-match-count'
 405 lines matches `message-cite-prefix-regexp' with the same prefix.
 406
 407 Lines matching `gnus-cite-attribution-suffix' and perhaps
 408 `gnus-cite-attribution-prefix' are considered attribution lines."
 409   (interactive (list 'force))
 410   (with-current-buffer (if same-buffer (current-buffer) gnus-article-buffer)
 411     (gnus-cite-parse-maybe force)
 412     (let ((buffer-read-only nil)
 413           (alist gnus-cite-prefix-alist)
 414           (faces gnus-cite-face-list)
 415           (inhibit-point-motion-hooks t)
 416           face entry prefix skip numbers number face-alist)
 417       ;; Loop through citation prefixes.
 418       (while alist
 419         (setq entry (car alist)
 420               alist (cdr alist)
 421               prefix (car entry)
 422               numbers (cdr entry)
 423               face (car faces)
 424               faces (or (cdr faces) gnus-cite-face-list)
 425               face-alist (cons (cons prefix face) face-alist))
 426         (while numbers
 427           (setq number (car numbers)
 428                 numbers (cdr numbers))
 429           (and (not (assq number gnus-cite-attribution-alist))
 430                (not (assq number gnus-cite-loose-attribution-alist))
 431                (gnus-cite-add-face number prefix face))))
 432       ;; Loop through attribution lines.
 433       (setq alist gnus-cite-attribution-alist)
 434       (while alist
 435         (setq entry (car alist)
 436               alist (cdr alist)
 437               number (car entry)
 438               prefix (cdr entry)
 439               skip (gnus-cite-find-prefix number)
 440               face (cdr (assoc prefix face-alist)))
 441         ;; Add attribution button.
 442         (goto-char (point-min))
 443         (forward-line (1- number))
 444         (when (re-search-forward gnus-cite-attribution-suffix
 445                                  (point-at-eol)
 446                                  t)
 447           (gnus-article-add-button (match-beginning 1) (match-end 1)
 448                                    'gnus-cite-toggle prefix))
 449         ;; Highlight attribution line.
 450         (gnus-cite-add-face number skip face)
 451         (gnus-cite-add-face number skip gnus-cite-attribution-face))
 452       ;; Loop through attribution lines.
 453       (setq alist gnus-cite-loose-attribution-alist)
 454       (while alist
 455         (setq entry (car alist)
 456               alist (cdr alist)
 457               number (car entry)
 458               skip (gnus-cite-find-prefix number))
 459         (gnus-cite-add-face number skip gnus-cite-attribution-face)))))
 460
 461 (defun gnus-dissect-cited-text ()
 462   "Dissect the article buffer looking for cited text."
 463   (with-current-buffer gnus-article-buffer
 464     (gnus-cite-parse-maybe nil t)
 465     (let ((alist gnus-cite-prefix-alist)
 466           prefix numbers number marks m)
 467       ;; Loop through citation prefixes.
 468       (while alist
 469         (setq numbers (pop alist)
 470               prefix (pop numbers))
 471         (while numbers
 472           (setq number (pop numbers))
 473           (goto-char (point-min))
 474           (forward-line number)
 475           (push (cons (point-marker) "") marks)
 476           (while (and numbers
 477                       (= (1- number) (car numbers)))
 478             (setq number (pop numbers)))
 479           (goto-char (point-min))
 480           (forward-line (1- number))
 481           (push (cons (point-marker) prefix) marks)))
 482       ;; Skip to the beginning of the body.
 483       (article-goto-body)
 484       (push (cons (point-marker) "") marks)
 485       ;; Find the end of the body.
 486       (goto-char (point-max))
 487       (gnus-article-search-signature)
 488       (push (cons (point-marker) "") marks)
 489       ;; Sort the marks.
 490       (setq marks (sort marks 'car-less-than-car))
 491       (let ((omarks marks))
 492         (setq marks nil)
 493         (while (cdr omarks)
 494           (if (= (caar omarks) (caadr omarks))
 495               (progn
 496                 (unless (equal (cdar omarks) "")
 497                   (push (car omarks) marks))
 498                 (unless (equal (cdadr omarks) "")
 499                   (push (cadr omarks) marks))
 500                 (unless (and (equal (cdar omarks) "")
 501                              (equal (cdadr omarks) "")
 502                              (not (cddr omarks)))
 503                   (setq omarks (cdr omarks))))
 504             (push (car omarks) marks))
 505           (setq omarks (cdr omarks)))
 506         (when (car omarks)
 507           (push (car omarks) marks))
 508         (setq marks (setq m (nreverse marks)))
 509         (while (cddr m)
 510           (if (and (equal (cdadr m) "")
 511                    (equal (cdar m) (cdaddr m))
 512                    (goto-char (caadr m))
 513                    (forward-line 1)
 514                    (= (point) (caaddr m)))
 515               (setcdr m (cdddr m))
 516             (setq m (cdr m))))
 517         marks))))
 518
 519 (defun gnus-article-fill-cited-long-lines ()
 520   (gnus-article-fill-cited-article nil t))
 521
 522 (defun gnus-article-fill-cited-article (&optional width long-lines)
 523   "Do word wrapping in the current article.
 524 If WIDTH (the numerical prefix), use that text width when
 525 filling.  If LONG-LINES, only fill sections that have lines
 526 longer than the frame width."
 527   (interactive "P")
 528   (with-current-buffer gnus-article-buffer
 529     (let ((buffer-read-only nil)
 530           (inhibit-point-motion-hooks t)
 531           (marks (gnus-dissect-cited-text))
 532           (adaptive-fill-mode nil)
 533           (filladapt-mode nil)
 534           (fill-column (if width (prefix-numeric-value width) fill-column)))
 535       (save-restriction
 536         (while (cdr marks)
 537           (narrow-to-region (caar marks) (caadr marks))
 538           (let ((adaptive-fill-regexp
 539                  (concat "^" (regexp-quote (cdar marks)) " *"))
 540                 (fill-prefix
 541                  (if (string= (cdar marks) "") ""
 542                    (concat (cdar marks) " ")))
 543                 (do-fill (not long-lines))
 544                 use-hard-newlines)
 545             (unless do-fill
 546               (setq do-fill (gnus-article-foldable-buffer (cdar marks))))
 547             (when do-fill
 548               (fill-region (point-min) (point-max))))
 549           (set-marker (caar marks) nil)
 550           (setq marks (cdr marks)))
 551         (when marks
 552           (set-marker (caar marks) nil))
 553         ;; All this information is now incorrect.
 554         (setq gnus-cite-prefix-alist nil
 555               gnus-cite-attribution-alist nil
 556               gnus-cite-loose-prefix-alist nil
 557               gnus-cite-loose-attribution-alist nil
 558               gnus-cite-article nil)))))
 559
 560 (defun gnus-article-foldable-buffer (prefix)
 561   (let ((do-fill nil)
 562         columns)
 563     (goto-char (point-min))
 564     (while (not (eobp))
 565       (forward-char (length prefix))
 566       (skip-chars-forward " \t")
 567       (unless (eolp)
 568         (let ((elem (assq (current-column) columns)))
 569           (unless elem
 570             (setq elem (cons (current-column) 0))
 571             (push elem columns))
 572           (setcdr elem (1+ (cdr elem)))))
 573       (end-of-line)
 574       (when (> (current-column) (frame-width))
 575         (setq do-fill t))
 576       (forward-line 1))
 577     (and do-fill
 578          ;; We know know that there are long lines here, but does this look
 579          ;; like code?  Check for ragged edges on the left.
 580          (< (length columns) 3))))
 581
 582 (defun gnus-article-natural-long-line-p ()
 583   "Return true if the current line is long, and it's natural text."
 584   (save-excursion
 585     (beginning-of-line)
 586     (and
 587      ;; The line is long.
 588      (> (- (line-end-position) (line-beginning-position))
 589         (frame-width))
 590      ;; It doesn't start with spaces.
 591      (not (looking-at "    "))
 592      ;; Not cited text.
 593      (let ((line-number (1+ (count-lines (point-min) (point))))
 594            citep)
 595        (dolist (elem gnus-cite-prefix-alist)
 596          (when (member line-number (cdr elem))
 597            (setq citep t)))
 598        (not citep)))))
 599
 600 (defun gnus-article-hide-citation (&optional arg force)
 601   "Toggle hiding of all cited text except attribution lines.
 602 See the documentation for `gnus-article-highlight-citation'.
 603 If given a negative prefix, always show; if given a positive prefix,
 604 always hide."
 605   (interactive (append (gnus-article-hidden-arg) (list 'force)))
 606   (gnus-set-format 'cited-opened-text-button t)
 607   (gnus-set-format 'cited-closed-text-button t)
 608   (with-current-buffer gnus-article-buffer
 609     (let ((buffer-read-only nil)
 610           marks
 611           (inhibit-point-motion-hooks t)
 612           (props (nconc (list 'article-type 'cite)
 613                         gnus-hidden-properties))
 614           (point (point-min))
 615           found beg end start)
 616       (while (setq point
 617                    (text-property-any point (point-max)
 618                                       'gnus-callback
 619                                       'gnus-article-toggle-cited-text))
 620         (setq found t)
 621         (goto-char point)
 622         (gnus-article-toggle-cited-text
 623          (get-text-property point 'gnus-data) arg)
 624         (forward-line 1)
 625         (setq point (point)))
 626       (unless found
 627         (setq marks (gnus-dissect-cited-text))
 628         (while marks
 629           (setq beg nil
 630                 end nil)
 631           (while (and marks (string= (cdar marks) ""))
 632             (setq marks (cdr marks)))
 633           (when marks
 634             (setq beg (caar marks)))
 635           (while (and marks (not (string= (cdar marks) "")))
 636             (setq marks (cdr marks)))
 637           (when marks
 638             (setq end (caar marks)))
 639           ;; Skip past lines we want to leave visible.
 640           (when (and beg end gnus-cited-lines-visible)
 641             (goto-char beg)
 642             (forward-line (if (consp gnus-cited-lines-visible)
 643                               (car gnus-cited-lines-visible)
 644                             gnus-cited-lines-visible))
 645             (if (>= (point) end)
 646                 (setq beg nil)
 647               (setq beg (point-marker))
 648               (when (consp gnus-cited-lines-visible)
 649                 (goto-char end)
 650                 (forward-line (- (cdr gnus-cited-lines-visible)))
 651                 (if (<= (point) beg)
 652                     (setq beg nil)
 653                   (setq end (point-marker))))))
 654           (when (and beg end)
 655             (gnus-add-wash-type 'cite)
 656             ;; We use markers for the end-points to facilitate later
 657             ;; wrapping and mangling of text.
 658             (setq beg (set-marker (make-marker) beg)
 659                   end (set-marker (make-marker) end))
 660             (gnus-add-text-properties-when 'article-type nil beg end props)
 661             (goto-char beg)
 662             (when (and gnus-cite-blank-line-after-header
 663                        (not (save-excursion (search-backward "\n\n" nil t))))
 664               (insert "\n"))
 665             (put-text-property
 666              (setq start (point-marker))
 667              (progn
 668                (gnus-article-add-button
 669                 (point)
 670                 (progn (eval gnus-cited-closed-text-button-line-format-spec)
 671                        (point))
 672                 `gnus-article-toggle-cited-text
 673                 (list (cons beg end) start))
 674                (point))
 675              'article-type 'annotation)
 676             (set-marker beg (point))))))))
 677
 678 (defun gnus-article-toggle-cited-text (args &optional arg)
 679   "Toggle hiding the text in REGION.
 680 ARG can be nil or a number.  Positive means hide, negative
 681 means show, nil means toggle."
 682   (let* ((region (car args))
 683          (beg (car region))
 684          (end (cdr region))
 685          (start (cadr args))
 686          (hidden
 687           (text-property-any beg (1- end) 'article-type 'cite))
 688          (inhibit-point-motion-hooks t)
 689          buffer-read-only)
 690     (when (or (null arg)
 691               (zerop arg)
 692               (and (> arg 0) (not hidden))
 693               (and (< arg 0) hidden))
 694       (if hidden
 695           (progn
 696             ;; Can't remove 'cite from g-a-wash-types here because
 697             ;; multiple citations may be hidden -jas
 698             (gnus-remove-text-properties-when
 699              'article-type 'cite beg end
 700              (cons 'article-type (cons 'cite
 701                                        gnus-hidden-properties))))
 702         (gnus-add-wash-type 'cite)
 703         (gnus-add-text-properties-when
 704          'article-type nil beg end
 705          (cons 'article-type (cons 'cite
 706                                    gnus-hidden-properties))))
 707       (let ((gnus-article-mime-handle-alist-1 gnus-article-mime-handle-alist))
 708         (gnus-set-mode-line 'article))
 709       (save-excursion
 710         (goto-char start)
 711         (gnus-delete-line)
 712         (put-text-property
 713          (point)
 714          (progn
 715            (gnus-article-add-button
 716             (point)
 717             (progn (eval
 718                     (if hidden
 719                         gnus-cited-opened-text-button-line-format-spec
 720                       gnus-cited-closed-text-button-line-format-spec))
 721                    (point))
 722             `gnus-article-toggle-cited-text
 723             args)
 724            (point))
 725          'article-type 'annotation)))))
 726
 727 (defun gnus-article-hide-citation-maybe (&optional arg force)
 728   "Toggle hiding of cited text that has an attribution line.
 729 If given a negative prefix, always show; if given a positive prefix,
 730 always hide.
 731 This will do nothing unless at least `gnus-cite-hide-percentage'
 732 percent and at least `gnus-cite-hide-absolute' lines of the body is
 733 cited text with attributions.  When called interactively, these two
 734 variables are ignored.
 735 See also the documentation for `gnus-article-highlight-citation'."
 736   (interactive (append (gnus-article-hidden-arg) '(force)))
 737   (with-current-buffer gnus-article-buffer
 738     (gnus-delete-wash-type 'cite)
 739     (unless (gnus-article-check-hidden-text 'cite arg)
 740       (save-excursion
 741         (gnus-cite-parse-maybe force)
 742         (article-goto-body)
 743         (let ((start (point))
 744               (atts gnus-cite-attribution-alist)
 745               (buffer-read-only nil)
 746               (inhibit-point-motion-hooks t)
 747               (hidden 0)
 748               total)
 749           (goto-char (point-max))
 750           (gnus-article-search-signature)
 751           (setq total (count-lines start (point)))
 752           (while atts
 753             (setq hidden (+ hidden (length (cdr (assoc (cdar atts)
 754                                                        gnus-cite-prefix-alist))))
 755                   atts (cdr atts)))
 756           (when (or force
 757                     (and (> (* 100 hidden) (* gnus-cite-hide-percentage total))
 758                          (> hidden gnus-cite-hide-absolute)))
 759             (gnus-add-wash-type 'cite)
 760             (setq atts gnus-cite-attribution-alist)
 761             (while atts
 762               (setq total (cdr (assoc (cdar atts) gnus-cite-prefix-alist))
 763                     atts (cdr atts))
 764               (while total
 765                 (setq hidden (car total)
 766                       total (cdr total))
 767                 (goto-char (point-min))
 768                 (forward-line (1- hidden))
 769                 (unless (assq hidden gnus-cite-attribution-alist)
 770                   (gnus-add-text-properties
 771                    (point) (progn (forward-line 1) (point))
 772                    (nconc (list 'article-type 'cite)
 773                           gnus-hidden-properties)))))))))
 774     (gnus-set-mode-line 'article)))
 775
 776 (defun gnus-article-hide-citation-in-followups ()
 777   "Hide cited text in non-root articles."
 778   (interactive)
 779   (with-current-buffer gnus-article-buffer
 780     (let ((article (cdr gnus-article-current)))
 781       (unless (with-current-buffer gnus-summary-buffer
 782                 (gnus-article-displayed-root-p article))
 783         (gnus-article-hide-citation)))))
 784
 785 ;;; Internal functions:
 786
 787 (defun gnus-cite-parse-maybe (&optional force no-overlay)
 788   "Always parse the buffer."
 789   (gnus-cite-localize)
 790   ;;Reset parser information.
 791   (setq gnus-cite-prefix-alist nil
 792         gnus-cite-attribution-alist nil
 793         gnus-cite-loose-prefix-alist nil
 794         gnus-cite-loose-attribution-alist nil)
 795   (unless no-overlay
 796     (gnus-cite-delete-overlays))
 797   ;; Parse if not too large.
 798   (if (and gnus-cite-parse-max-size
 799            (> (buffer-size) gnus-cite-parse-max-size))
 800       ()
 801     (setq gnus-cite-article (cons (car gnus-article-current)
 802                                   (cdr gnus-article-current)))
 803     (gnus-cite-parse-wrapper)))
 804
 805 (defun gnus-cite-delete-overlays ()
 806   (dolist (overlay gnus-cite-overlay-list)
 807     (ignore-errors
 808       (when (or (not (gnus-overlay-end overlay))
 809                 (and (>= (gnus-overlay-end overlay) (point-min))
 810                      (<= (gnus-overlay-end overlay) (point-max))))
 811         (setq gnus-cite-overlay-list (delete overlay gnus-cite-overlay-list))
 812         (ignore-errors
 813           (gnus-delete-overlay overlay))))))
 814
 815 (defun gnus-cite-parse-wrapper ()
 816   ;; Wrap chopped gnus-cite-parse.
 817   (article-goto-body)
 818   (let ((inhibit-point-motion-hooks t))
 819     (save-excursion
 820       (gnus-cite-parse-attributions))
 821     (save-excursion
 822       (gnus-cite-parse))
 823     (save-excursion
 824       (gnus-cite-connect-attributions))))
 825
 826 (defun gnus-cite-parse ()
 827   ;; Parse and connect citation prefixes and attribution lines.
 828
 829   ;; Parse current buffer searching for citation prefixes.
 830   (let ((line (1+ (count-lines (point-min) (point))))
 831         (case-fold-search t)
 832         (max (save-excursion
 833                (goto-char (point-max))
 834                (gnus-article-search-signature)
 835                (point)))
 836         (prefix-regexp (concat "^\\(" message-cite-prefix-regexp "\\)"))
 837         alist entry start begin end numbers prefix guess-limit)
 838     ;; Get all potential prefixes in `alist'.
 839     (while (< (point) max)
 840       ;; Each line.
 841       (setq begin (point)
 842             guess-limit (progn (skip-chars-forward "^> \t\r\n") (point))
 843             end (point-at-bol 2)
 844             start end)
 845       (goto-char begin)
 846       ;; Ignore standard Supercite attribution prefix.
 847       (when (and (< guess-limit (+ begin gnus-cite-max-prefix))
 848                  (looking-at gnus-supercite-regexp))
 849         (if (match-end 1)
 850             (setq end (1+ (match-end 1)))
 851           (setq end (1+ begin))))
 852       ;; Ignore very long prefixes.
 853       (when (> end (+ begin gnus-cite-max-prefix))
 854         (setq end (+ begin gnus-cite-max-prefix)))
 855       ;; Ignore quoted envelope From_.
 856       (when (and gnus-cite-ignore-quoted-from
 857                  (prog2
 858                      (setq case-fold-search nil)
 859                      (looking-at ">From ")
 860                    (setq case-fold-search t)))
 861         (setq end (1+ begin)))
 862       (while (re-search-forward prefix-regexp (1- end) t)
 863         ;; Each prefix.
 864         (setq end (match-end 0)
 865               prefix (buffer-substring begin end))
 866         (set-text-properties 0 (length prefix) nil prefix)
 867         (setq entry (assoc prefix alist))
 868         (if entry
 869             (setcdr entry (cons line (cdr entry)))
 870           (push (list prefix line) alist))
 871         (goto-char begin))
 872       (goto-char start)
 873       (setq line (1+ line)))
 874     ;; Horrible special case for some Microsoft mailers.
 875     (goto-char (point-min))
 876     (setq start t begin nil entry nil)
 877     (while start
 878       ;; Assume this search ends up at the beginning of a line.
 879       (if (re-search-forward gnus-cite-unsightly-citation-regexp max t)
 880           (progn
 881             (when (number-or-marker-p start)
 882               (setq begin (count-lines (point-min) start)
 883                     end (count-lines (point-min) (match-beginning 0))))
 884             (setq start (match-end 0)))
 885         (when (number-or-marker-p start)
 886           (setq begin (count-lines (point-min) start)
 887                 end (count-lines (point-min) max)))
 888         (setq start nil))
 889       (when begin
 890         (while (< begin end)
 891           ;; Need to do 1+ because we're in the bol.
 892           (push (setq begin (1+ begin)) entry))))
 893     (when entry
 894       (push (cons "" entry) alist))
 895     ;; We got all the potential prefixes.  Now create
 896     ;; `gnus-cite-prefix-alist' containing the oldest prefix for each
 897     ;; line that appears at least `gnus-cite-minimum-match-count'
 898     ;; times.  First sort them by length.  Longer is older.
 899     (setq alist (sort alist (lambda (a b)
 900                               (> (length (car a)) (length (car b))))))
 901     (while alist
 902       (setq entry (car alist)
 903             prefix (car entry)
 904             numbers (cdr entry)
 905             alist (cdr alist))
 906       (cond ((null numbers)
 907              ;; No lines with this prefix that wasn't also part of
 908              ;; a longer prefix.
 909              )
 910             ((< (length numbers) gnus-cite-minimum-match-count)
 911              ;; Too few lines with this prefix.  We keep it a bit
 912              ;; longer in case it is an exact match for an attribution
 913              ;; line, but we don't remove the line from other
 914              ;; prefixes.
 915              (push entry gnus-cite-prefix-alist))
 916             (t
 917              (push entry
 918                    gnus-cite-prefix-alist)
 919              ;; Remove articles from other prefixes.
 920              (let ((loop alist)
 921                    current)
 922                (while loop
 923                  (setq current (car loop)
 924                        loop (cdr loop))
 925                  (setcdr current
 926                          (gnus-set-difference (cdr current) numbers)))))))))
 927
 928 (defun gnus-cite-parse-attributions ()
 929   (let (al-alist)
 930     ;; Parse attributions
 931     (while (re-search-forward gnus-cite-attribution-suffix (point-max) t)
 932       (let* ((start (match-beginning 0))
 933              (end (match-end 0))
 934              (wrote (count-lines (point-min) end))
 935              (prefix (gnus-cite-find-prefix wrote))
 936              ;; Check previous line for an attribution leader.
 937              (tag (progn
 938                     (beginning-of-line 1)
 939                     (when (looking-at gnus-supercite-secondary-regexp)
 940                       (buffer-substring (match-beginning 1)
 941                                         (match-end 1)))))
 942              (in (progn
 943                    (goto-char start)
 944                    (and (re-search-backward gnus-cite-attribution-prefix
 945                                             (save-excursion
 946                                               (beginning-of-line 0)
 947                                               (point))
 948                                             t)
 949                         (not (re-search-forward gnus-cite-attribution-suffix
 950                                                 start t))
 951                         (count-lines (point-min) (1+ (point)))))))
 952         (when (eq wrote in)
 953           (setq in nil))
 954         (goto-char end)
 955         ;; don't add duplicates
 956         (let ((al (buffer-substring (save-excursion (beginning-of-line 0)
 957                                                     (1+ (point)))
 958                                     end)))
 959           (when (not (assoc al al-alist))
 960             (push (list wrote in prefix tag)
 961                   gnus-cite-loose-attribution-alist)
 962             (push (cons al t) al-alist)))))))
 963
 964 (defun gnus-cite-connect-attributions ()
 965   ;; Connect attributions to citations
 966
 967   ;; No citations have been connected to attribution lines yet.
 968   (setq gnus-cite-loose-prefix-alist (append gnus-cite-prefix-alist nil))
 969
 970   ;; Parse current buffer searching for attribution lines.
 971   ;; Find exact supercite citations.
 972   (gnus-cite-match-attributions 'small nil
 973                                 (lambda (prefix tag)
 974                                   (when tag
 975                                     (concat "\\`"
 976                                             (regexp-quote prefix) "[ \t]*"
 977                                             (regexp-quote tag) ">"))))
 978   ;; Find loose supercite citations after attributions.
 979   (gnus-cite-match-attributions 'small t
 980                                 (lambda (prefix tag)
 981                                   (when tag
 982                                     (concat "\\<"
 983                                             (regexp-quote tag)
 984                                             "\\>"))))
 985   ;; Find loose supercite citations anywhere.
 986   (gnus-cite-match-attributions 'small nil
 987                                 (lambda (prefix tag)
 988                                   (when tag
 989                                     (concat "\\<"
 990                                             (regexp-quote tag)
 991                                             "\\>"))))
 992   ;; Find nested citations after attributions.
 993   (gnus-cite-match-attributions 'small-if-unique t
 994                                 (lambda (prefix tag)
 995                                   (concat "\\`" (regexp-quote prefix) ".+")))
 996   ;; Find nested citations anywhere.
 997   (gnus-cite-match-attributions 'small nil
 998                                 (lambda (prefix tag)
 999                                   (concat "\\`" (regexp-quote prefix) ".+")))
1000   ;; Remove loose prefixes with too few lines.
1001   (let ((alist gnus-cite-loose-prefix-alist)
1002         entry)
1003     (while alist
1004       (setq entry (car alist)
1005             alist (cdr alist))
1006       (when (< (length (cdr entry)) gnus-cite-minimum-match-count)
1007         (setq gnus-cite-prefix-alist
1008               (delq entry gnus-cite-prefix-alist)
1009               gnus-cite-loose-prefix-alist
1010               (delq entry gnus-cite-loose-prefix-alist)))))
1011   ;; Find flat attributions.
1012   (gnus-cite-match-attributions 'first t nil)
1013   ;; Find any attributions (are we getting desperate yet?).
1014   (gnus-cite-match-attributions 'first nil nil))
1015
1016 (defun gnus-cite-match-attributions (sort after fun)
1017   ;; Match all loose attributions and citations (SORT AFTER FUN) .
1018   ;;
1019   ;; If SORT is `small', the citation with the shortest prefix will be
1020   ;; used, if it is `first' the first prefix will be used, if it is
1021   ;; `small-if-unique' the shortest prefix will be used if the
1022   ;; attribution line does not share its own prefix with other
1023   ;; loose attribution lines, otherwise the first prefix will be used.
1024   ;;
1025   ;; If AFTER is non-nil, only citations after the attribution line
1026   ;; will be considered.
1027   ;;
1028   ;; If FUN is non-nil, it will be called with the arguments (WROTE
1029   ;; PREFIX TAG) and expected to return a regular expression.  Only
1030   ;; citations whose prefix matches the regular expression will be
1031   ;; considered.
1032   ;;
1033   ;; WROTE is the attribution line number.
1034   ;; PREFIX is the attribution line prefix.
1035   ;; TAG is the Supercite tag on the attribution line.
1036   (let ((atts gnus-cite-loose-attribution-alist)
1037         (case-fold-search t)
1038         att wrote in prefix tag regexp limit smallest best size)
1039     (while atts
1040       (setq att (car atts)
1041             atts (cdr atts)
1042             wrote (nth 0 att)
1043             in (nth 1 att)
1044             prefix (nth 2 att)
1045             tag (nth 3 att)
1046             regexp (if fun (funcall fun prefix tag) "")
1047             size (cond ((eq sort 'small) t)
1048                        ((eq sort 'first) nil)
1049                        (t (< (length (gnus-cite-find-loose prefix)) 2)))
1050             limit (if after wrote -1)
1051             smallest 1000000
1052             best nil)
1053       (let ((cites gnus-cite-loose-prefix-alist)
1054             cite candidate numbers first compare)
1055         (while cites
1056           (setq cite (car cites)
1057                 cites (cdr cites)
1058                 candidate (car cite)
1059                 numbers (cdr cite)
1060                 first (apply 'min numbers)
1061                 compare (if size (length candidate) first))
1062           (and (> first limit)
1063                regexp
1064                (string-match regexp candidate)
1065                (< compare smallest)
1066                (setq best cite
1067                      smallest compare))))
1068       (if (null best)
1069           ()
1070         (setq gnus-cite-loose-attribution-alist
1071               (delq att gnus-cite-loose-attribution-alist))
1072         (push (cons wrote (car best)) gnus-cite-attribution-alist)
1073         (when in
1074           (push (cons in (car best)) gnus-cite-attribution-alist))
1075         (when (memq best gnus-cite-loose-prefix-alist)
1076           (let ((loop gnus-cite-prefix-alist)
1077                 (numbers (cdr best))
1078                 current)
1079             (setq gnus-cite-loose-prefix-alist
1080                   (delq best gnus-cite-loose-prefix-alist))
1081             (while loop
1082               (setq current (car loop)
1083                     loop (cdr loop))
1084               (if (eq current best)
1085                   ()
1086                 (setcdr current (gnus-set-difference (cdr current) numbers))
1087                 (when (null (cdr current))
1088                   (setq gnus-cite-loose-prefix-alist
1089                         (delq current gnus-cite-loose-prefix-alist)
1090                         atts (delq current atts)))))))))))
1091
1092 (defun gnus-cite-find-loose (prefix)
1093   ;; Return a list of loose attribution lines prefixed by PREFIX.
1094   (let* ((atts gnus-cite-loose-attribution-alist)
1095          att line lines)
1096     (while atts
1097       (setq att (car atts)
1098             line (car att)
1099             atts (cdr atts))
1100       (when (string-equal (gnus-cite-find-prefix line) prefix)
1101         (push line lines)))
1102     lines))
1103
1104 (defun gnus-cite-add-face (number prefix face)
1105   ;; At line NUMBER, ignore PREFIX and add FACE to the rest of the line.
1106   (when face
1107     (let ((inhibit-point-motion-hooks t)
1108           from to overlay)
1109       (goto-char (point-min))
1110       (when (zerop (forward-line (1- number)))
1111         (forward-char (length prefix))
1112         (skip-chars-forward " \t")
1113         (setq from (point))
1114         (end-of-line 1)
1115         (skip-chars-backward " \t")
1116         (setq to (point))
1117         (when (< from to)
1118           (push (setq overlay (gnus-make-overlay from to))
1119                 gnus-cite-overlay-list)
1120           (gnus-overlay-put overlay 'evaporate t)
1121           (gnus-overlay-put overlay 'face face))))))
1122
1123 (defun gnus-cite-toggle (prefix)
1124   (with-current-buffer gnus-article-buffer
1125     (gnus-cite-parse-maybe nil t)
1126     (let ((buffer-read-only nil)
1127           (numbers (cdr (assoc prefix gnus-cite-prefix-alist)))
1128           (inhibit-point-motion-hooks t)
1129           number)
1130       (while numbers
1131         (setq number (car numbers)
1132               numbers (cdr numbers))
1133         (goto-char (point-min))
1134         (forward-line (1- number))
1135         (cond ((get-text-property (point) 'invisible)
1136                ;; Can't remove 'cite from g-a-wash-types here because
1137                ;; multiple citations may be hidden -jas
1138                (remove-text-properties (point) (progn (forward-line 1) (point))
1139                                        gnus-hidden-properties))
1140               ((assq number gnus-cite-attribution-alist))
1141               (t
1142                (gnus-add-wash-type 'cite)
1143                (gnus-add-text-properties
1144                 (point) (progn (forward-line 1) (point))
1145                 (nconc (list 'article-type 'cite)
1146                        gnus-hidden-properties))))
1147         (let ((gnus-article-mime-handle-alist-1
1148                gnus-article-mime-handle-alist))
1149           (gnus-set-mode-line 'article))))))
1150
1151 (defun gnus-cite-find-prefix (line)
1152   ;; Return citation prefix for LINE.
1153   (let ((alist gnus-cite-prefix-alist)
1154         (prefix "")
1155         entry)
1156     (while alist
1157       (setq entry (car alist)
1158             alist (cdr alist))
1159       (when (memq line (cdr entry))
1160         (setq prefix (car entry))))
1161     prefix))
1162
1163 (defun gnus-cite-localize ()
1164   "Make the citation variables local to the article buffer."
1165   (let ((vars '(gnus-cite-article
1166                 gnus-cite-overlay-list gnus-cite-prefix-alist
1167                 gnus-cite-attribution-alist gnus-cite-loose-prefix-alist
1168                 gnus-cite-loose-attribution-alist)))
1169     (while vars
1170       (make-local-variable (pop vars)))))
1171
1172 (defun gnus-cited-line-p ()
1173   "Say whether the current line is a cited line."
1174   (save-excursion
1175     (beginning-of-line)
1176     (let ((found nil))
1177       (dolist (prefix (mapcar 'car gnus-cite-prefix-alist))
1178         (when (string= (buffer-substring (point) (+ (length prefix) (point)))
1179                        prefix)
1180           (setq found t)))
1181       found)))
1182
1183
1184 ;; Highlighting of different citation levels in message-mode.
1185 ;; - message-cite-prefix will be overridden if this is enabled.
1186
1187 (defvar gnus-message-max-citation-depth
1188   (length gnus-cite-face-list)
1189   "Maximum supported level of citation.")
1190
1191 (defvar gnus-message-cite-prefix-regexp
1192   (concat "^\\(?:" message-cite-prefix-regexp "\\)"))
1193
1194 (defun gnus-message-search-citation-line (limit)
1195   "Search for a cited line and set match data accordingly.
1196 Returns nil if there is no such line before LIMIT, t otherwise."
1197   (when (re-search-forward gnus-message-cite-prefix-regexp limit t)
1198     (let ((cdepth (min (length (apply 'concat
1199                                       (split-string
1200                                        (match-string-no-properties 0)
1201                                        "[ \t [:alnum:]]+")))
1202                        gnus-message-max-citation-depth))
1203           (mlist (make-list (* (1+ gnus-message-max-citation-depth) 2) nil))
1204           (start (point-at-bol))
1205           (end (point-at-eol)))
1206       (setcar mlist start)
1207       (setcar (cdr mlist) end)
1208       (setcar (nthcdr (* cdepth 2) mlist) start)
1209       (setcar (nthcdr (1+ (* cdepth 2)) mlist) end)
1210       (set-match-data mlist))
1211     t))
1212
1213 (defvar gnus-message-citation-keywords
1214   ;; eval-when-compile ;; This breaks in XEmacs
1215   `((gnus-message-search-citation-line
1216      ,@(let ((list nil)
1217              (count 1))
1218          ;; (require 'gnus-cite)
1219          (dolist (face gnus-cite-face-list (nreverse list))
1220            (push (list count (list 'quote face) 'prepend t) list)
1221            (setq count (1+ count)))))) ;;
1222   "Keywords for highlighting different levels of message citations.")
1223
1224 (defvar font-lock-defaults-computed)
1225 (defvar font-lock-keywords)
1226 (defvar font-lock-set-defaults)
1227
1228 (eval-and-compile
1229   (unless (featurep 'xemacs)
1230     (autoload 'font-lock-set-defaults "font-lock")))
1231
1232 (define-minor-mode gnus-message-citation-mode
1233   "Toggle `gnus-message-citation-mode' in current buffer.
1234 This buffer local minor mode provides additional font-lock support for
1235 nested citations.
1236 With prefix ARG, turn `gnus-message-citation-mode' on if and only if ARG
1237 is positive.
1238 Automatically turn `font-lock-mode' on when `gnus-message-citation-mode'
1239 is turned on."
1240   nil ;; init-value
1241   "" ;; lighter
1242   nil ;; keymap
1243   (when (eq major-mode 'message-mode)
1244     (let ((defaults (car (if (featurep 'xemacs)
1245                              (get 'message-mode 'font-lock-defaults)
1246                            font-lock-defaults)))
1247           default keywords)
1248       (while defaults
1249         (setq default (if (consp defaults)
1250                           (pop defaults)
1251                         (prog1
1252                             defaults
1253                           (setq defaults nil))))
1254         (if gnus-message-citation-mode
1255             ;; `gnus-message-citation-keywords' should be the last
1256             ;; elements of the keywords because the others are unlikely
1257             ;; to have the OVERRIDE flags -- XEmacs applies a keyword
1258             ;; having no OVERRIDE flag to matched text even if it has
1259             ;; already other faces, while Emacs doesn't.
1260             (set (make-local-variable default)
1261                  (append (default-value default)
1262                          gnus-message-citation-keywords))
1263           (kill-local-variable default))))
1264     ;; Force `font-lock-set-defaults' to update `font-lock-keywords'.
1265     (if (featurep 'xemacs)
1266         (progn
1267           (require 'font-lock)
1268           (setq font-lock-defaults-computed nil
1269                 font-lock-keywords nil))
1270       (setq font-lock-set-defaults nil))
1271     (font-lock-set-defaults)
1272     (cond ((symbol-value 'font-lock-mode)
1273            (font-lock-fontify-buffer))
1274           (gnus-message-citation-mode
1275            (font-lock-mode 1)))))
1276
1277 (defun turn-on-gnus-message-citation-mode ()
1278   "Turn on `gnus-message-citation-mode'."
1279   (gnus-message-citation-mode 1))
1280 (defun turn-off-gnus-message-citation-mode ()
1281   "Turn off `gnus-message-citation-mode'."
1282   (gnus-message-citation-mode -1))
1283
1284 (gnus-ems-redefine)
1285
1286 (provide 'gnus-cite)
1287
1288 ;; Local Variables:
1289 ;; coding: iso-8859-1
1290 ;; End:
1291
1292 ;;; gnus-cite.el ends here