lisp/gnus/gnus-int.el

   1 ;;; gnus-int.el --- backend interface functions for Gnus
   2 ;; Copyright (C) 1996, 1997, 1998, 1999, 2000
   3 ;;        Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; Keywords: news
   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 2, or (at your option)
  13 ;; 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; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;;; Code:
  28
  29 (eval-when-compile (require 'cl))
  30
  31 (require 'gnus)
  32
  33 (defcustom gnus-open-server-hook nil
  34   "Hook called just before opening connection to the news server."
  35   :group 'gnus-start
  36   :type 'hook)
  37
  38 ;;;
  39 ;;; Server Communication
  40 ;;;
  41
  42 (defun gnus-start-news-server (&optional confirm)
  43   "Open a method for getting news.
  44 If CONFIRM is non-nil, the user will be asked for an NNTP server."
  45   (let (how)
  46     (if gnus-current-select-method
  47         ;; Stream is already opened.
  48         nil
  49       ;; Open NNTP server.
  50       (unless gnus-nntp-service
  51         (setq gnus-nntp-server nil))
  52       (when confirm
  53         ;; Read server name with completion.
  54         (setq gnus-nntp-server
  55               (completing-read "NNTP server: "
  56                                (mapcar (lambda (server) (list server))
  57                                        (cons (list gnus-nntp-server)
  58                                              gnus-secondary-servers))
  59                                nil nil gnus-nntp-server)))
  60
  61       (when (and gnus-nntp-server
  62                  (stringp gnus-nntp-server)
  63                  (not (string= gnus-nntp-server "")))
  64         (setq gnus-select-method
  65               (cond ((or (string= gnus-nntp-server "")
  66                          (string= gnus-nntp-server "::"))
  67                      (list 'nnspool (system-name)))
  68                     ((string-match "^:" gnus-nntp-server)
  69                      (list 'nnmh gnus-nntp-server
  70                            (list 'nnmh-directory
  71                                  (file-name-as-directory
  72                                   (expand-file-name
  73                                    (substring gnus-nntp-server 1) "~/")))
  74                            (list 'nnmh-get-new-mail nil)))
  75                     (t
  76                      (list 'nntp gnus-nntp-server)))))
  77
  78       (setq how (car gnus-select-method))
  79       (cond
  80        ((eq how 'nnspool)
  81         (require 'nnspool)
  82         (gnus-message 5 "Looking up local news spool..."))
  83        ((eq how 'nnmh)
  84         (require 'nnmh)
  85         (gnus-message 5 "Looking up mh spool..."))
  86        (t
  87         (require 'nntp)))
  88       (setq gnus-current-select-method gnus-select-method)
  89       (gnus-run-hooks 'gnus-open-server-hook)
  90       (or
  91        ;; gnus-open-server-hook might have opened it
  92        (gnus-server-opened gnus-select-method)
  93        (gnus-open-server gnus-select-method)
  94        gnus-batch-mode
  95        (gnus-y-or-n-p
  96         (format
  97          "%s (%s) open error: '%s'.  Continue? "
  98          (car gnus-select-method) (cadr gnus-select-method)
  99          (gnus-status-message gnus-select-method)))
 100        (gnus-error 1 "Couldn't open server on %s"
 101                    (nth 1 gnus-select-method))))))
 102
 103 (defun gnus-check-group (group)
 104   "Try to make sure that the server where GROUP exists is alive."
 105   (let ((method (gnus-find-method-for-group group)))
 106     (or (gnus-server-opened method)
 107         (gnus-open-server method))))
 108
 109 (defun gnus-check-server (&optional method silent)
 110   "Check whether the connection to METHOD is down.
 111 If METHOD is nil, use `gnus-select-method'.
 112 If it is down, start it up (again)."
 113   (let ((method (or method gnus-select-method)))
 114     ;; Transform virtual server names into select methods.
 115     (when (stringp method)
 116       (setq method (gnus-server-to-method method)))
 117     (if (gnus-server-opened method)
 118         ;; The stream is already opened.
 119         t
 120       ;; Open the server.
 121       (unless silent
 122         (gnus-message 5 "Opening %s server%s..." (car method)
 123                       (if (equal (nth 1 method) "") ""
 124                         (format " on %s" (nth 1 method)))))
 125       (gnus-run-hooks 'gnus-open-server-hook)
 126       (prog1
 127           (gnus-open-server method)
 128         (unless silent
 129           (message ""))))))
 130
 131 (defun gnus-get-function (method function &optional noerror)
 132   "Return a function symbol based on METHOD and FUNCTION."
 133   ;; Translate server names into methods.
 134   (unless method
 135     (error "Attempted use of a nil select method"))
 136   (when (stringp method)
 137     (setq method (gnus-server-to-method method)))
 138   ;; Check cache of constructed names.
 139   (let* ((method-sym (if gnus-agent
 140                          (gnus-agent-get-function method)
 141                        (car method)))
 142          (method-fns (get method-sym 'gnus-method-functions))
 143          (func (let ((method-fnlist-elt (assq function method-fns)))
 144                  (unless method-fnlist-elt
 145                    (setq method-fnlist-elt
 146                          (cons function
 147                                (intern (format "%s-%s" method-sym function))))
 148                    (put method-sym 'gnus-method-functions
 149                         (cons method-fnlist-elt method-fns)))
 150                  (cdr method-fnlist-elt))))
 151     ;; Maybe complain if there is no function.
 152     (unless (fboundp func)
 153       (unless (car method)
 154         (error "Trying to require a method that doesn't exist"))
 155       (require (car method))
 156       (when (not (fboundp func))
 157         (if noerror
 158             (setq func nil)
 159           (error "No such function: %s" func))))
 160     func))
 161
 162 \f
 163 ;;;
 164 ;;; Interface functions to the backends.
 165 ;;;
 166
 167 (defun gnus-open-server (gnus-command-method)
 168   "Open a connection to GNUS-COMMAND-METHOD."
 169   (when (stringp gnus-command-method)
 170     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 171   (let ((elem (assoc gnus-command-method gnus-opened-servers)))
 172     ;; If this method was previously denied, we just return nil.
 173     (if (eq (nth 1 elem) 'denied)
 174         (progn
 175           (gnus-message 1 "Denied server")
 176           nil)
 177       ;; Open the server.
 178       (let ((result
 179              (funcall (gnus-get-function gnus-command-method 'open-server)
 180                       (nth 1 gnus-command-method)
 181                       (nthcdr 2 gnus-command-method))))
 182         ;; If this hasn't been opened before, we add it to the list.
 183         (unless elem
 184           (setq elem (list gnus-command-method nil)
 185                 gnus-opened-servers (cons elem gnus-opened-servers)))
 186         ;; Set the status of this server.
 187         (setcar (cdr elem) (if result 'ok 'denied))
 188         ;; Return the result from the "open" call.
 189         result))))
 190
 191 (defun gnus-close-server (gnus-command-method)
 192   "Close the connection to GNUS-COMMAND-METHOD."
 193   (when (stringp gnus-command-method)
 194     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 195   (funcall (gnus-get-function gnus-command-method 'close-server)
 196            (nth 1 gnus-command-method)))
 197
 198 (defun gnus-request-list (gnus-command-method)
 199   "Request the active file from GNUS-COMMAND-METHOD."
 200   (when (stringp gnus-command-method)
 201     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 202   (funcall (gnus-get-function gnus-command-method 'request-list)
 203            (nth 1 gnus-command-method)))
 204
 205 (defun gnus-request-list-newsgroups (gnus-command-method)
 206   "Request the newsgroups file from GNUS-COMMAND-METHOD."
 207   (when (stringp gnus-command-method)
 208     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 209   (funcall (gnus-get-function gnus-command-method 'request-list-newsgroups)
 210            (nth 1 gnus-command-method)))
 211
 212 (defun gnus-request-newgroups (date gnus-command-method)
 213   "Request all new groups since DATE from GNUS-COMMAND-METHOD."
 214   (when (stringp gnus-command-method)
 215     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 216   (let ((func (gnus-get-function gnus-command-method 'request-newgroups t)))
 217     (when func
 218       (funcall func date (nth 1 gnus-command-method)))))
 219
 220 (defun gnus-server-opened (gnus-command-method)
 221   "Check whether a connection to GNUS-COMMAND-METHOD has been opened."
 222   (unless (eq (gnus-server-status gnus-command-method)
 223               'denied)
 224     (when (stringp gnus-command-method)
 225       (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 226     (funcall (inline (gnus-get-function gnus-command-method 'server-opened))
 227              (nth 1 gnus-command-method))))
 228
 229 (defun gnus-status-message (gnus-command-method)
 230   "Return the status message from GNUS-COMMAND-METHOD.
 231 If GNUS-COMMAND-METHOD is a string, it is interpreted as a group name.   The method
 232 this group uses will be queried."
 233   (let ((gnus-command-method
 234          (if (stringp gnus-command-method)
 235              (gnus-find-method-for-group gnus-command-method)
 236            gnus-command-method)))
 237     (funcall (gnus-get-function gnus-command-method 'status-message)
 238              (nth 1 gnus-command-method))))
 239
 240 (defun gnus-request-regenerate (gnus-command-method)
 241   "Request a data generation from GNUS-COMMAND-METHOD."
 242   (when (stringp gnus-command-method)
 243     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 244   (funcall (gnus-get-function gnus-command-method 'request-regenerate)
 245            (nth 1 gnus-command-method)))
 246
 247 (defun gnus-request-group (group &optional dont-check gnus-command-method)
 248   "Request GROUP.  If DONT-CHECK, no information is required."
 249   (let ((gnus-command-method
 250          (or gnus-command-method (inline (gnus-find-method-for-group group)))))
 251     (when (stringp gnus-command-method)
 252       (setq gnus-command-method
 253             (inline (gnus-server-to-method gnus-command-method))))
 254     (funcall (inline (gnus-get-function gnus-command-method 'request-group))
 255              (gnus-group-real-name group) (nth 1 gnus-command-method)
 256              dont-check)))
 257
 258 (defun gnus-list-active-group (group)
 259   "Request active information on GROUP."
 260   (let ((gnus-command-method (gnus-find-method-for-group group))
 261         (func 'list-active-group))
 262     (when (gnus-check-backend-function func group)
 263       (funcall (gnus-get-function gnus-command-method func)
 264                (gnus-group-real-name group) (nth 1 gnus-command-method)))))
 265
 266 (defun gnus-request-group-description (group)
 267   "Request a description of GROUP."
 268   (let ((gnus-command-method (gnus-find-method-for-group group))
 269         (func 'request-group-description))
 270     (when (gnus-check-backend-function func group)
 271       (funcall (gnus-get-function gnus-command-method func)
 272                (gnus-group-real-name group) (nth 1 gnus-command-method)))))
 273
 274 (defun gnus-request-group-articles (group)
 275   "Request a list of existing articles in GROUP."
 276   (let ((gnus-command-method (gnus-find-method-for-group group))
 277         (func 'request-group-articles))
 278     (when (gnus-check-backend-function func group)
 279       (funcall (gnus-get-function gnus-command-method func)
 280                (gnus-group-real-name group) (nth 1 gnus-command-method)))))
 281
 282 (defun gnus-close-group (group)
 283   "Request the GROUP be closed."
 284   (let ((gnus-command-method (inline (gnus-find-method-for-group group))))
 285     (funcall (gnus-get-function gnus-command-method 'close-group)
 286              (gnus-group-real-name group) (nth 1 gnus-command-method))))
 287
 288 (defun gnus-retrieve-headers (articles group &optional fetch-old)
 289   "Request headers for ARTICLES in GROUP.
 290 If FETCH-OLD, retrieve all headers (or some subset thereof) in the group."
 291   (let ((gnus-command-method (gnus-find-method-for-group group)))
 292     (if (and gnus-use-cache (numberp (car articles)))
 293         (gnus-cache-retrieve-headers articles group fetch-old)
 294       (funcall (gnus-get-function gnus-command-method 'retrieve-headers)
 295                articles (gnus-group-real-name group)
 296                (nth 1 gnus-command-method) fetch-old))))
 297
 298 (defun gnus-retrieve-articles (articles group)
 299   "Request ARTICLES in GROUP."
 300   (let ((gnus-command-method (gnus-find-method-for-group group)))
 301     (funcall (gnus-get-function gnus-command-method 'retrieve-articles)
 302              articles (gnus-group-real-name group)
 303              (nth 1 gnus-command-method))))
 304
 305 (defun gnus-retrieve-groups (groups gnus-command-method)
 306   "Request active information on GROUPS from GNUS-COMMAND-METHOD."
 307   (when (stringp gnus-command-method)
 308     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 309   (funcall (gnus-get-function gnus-command-method 'retrieve-groups)
 310            groups (nth 1 gnus-command-method)))
 311
 312 (defun gnus-request-type (group &optional article)
 313   "Return the type (`post' or `mail') of GROUP (and ARTICLE)."
 314   (let ((gnus-command-method (gnus-find-method-for-group group)))
 315     (if (not (gnus-check-backend-function
 316               'request-type (car gnus-command-method)))
 317         'unknown
 318       (funcall (gnus-get-function gnus-command-method 'request-type)
 319                (gnus-group-real-name group) article))))
 320
 321 (defun gnus-request-set-mark (group action)
 322   "Set marks on articles in the backend."
 323   (let ((gnus-command-method (gnus-find-method-for-group group)))
 324     (if (not (gnus-check-backend-function
 325               'request-set-mark (car gnus-command-method)))
 326         action
 327       (funcall (gnus-get-function gnus-command-method 'request-set-mark)
 328                (gnus-group-real-name group) action
 329                (nth 1 gnus-command-method)))))
 330
 331 (defun gnus-request-update-mark (group article mark)
 332   "Allow the backend to change the mark the user tries to put on an article."
 333   (let ((gnus-command-method (gnus-find-method-for-group group)))
 334     (if (not (gnus-check-backend-function
 335               'request-update-mark (car gnus-command-method)))
 336         mark
 337       (funcall (gnus-get-function gnus-command-method 'request-update-mark)
 338                (gnus-group-real-name group) article mark))))
 339
 340 (defun gnus-request-article (article group &optional buffer)
 341   "Request the ARTICLE in GROUP.
 342 ARTICLE can either be an article number or an article Message-ID.
 343 If BUFFER, insert the article in that group."
 344   (let ((gnus-command-method (gnus-find-method-for-group group)))
 345     (funcall (gnus-get-function gnus-command-method 'request-article)
 346              article (gnus-group-real-name group)
 347              (nth 1 gnus-command-method) buffer)))
 348
 349 (defun gnus-request-head (article group)
 350   "Request the head of ARTICLE in GROUP."
 351   (let* ((gnus-command-method (gnus-find-method-for-group group))
 352          (head (gnus-get-function gnus-command-method 'request-head t))
 353          res clean-up)
 354     (cond
 355      ;; Check the cache.
 356      ((and gnus-use-cache
 357            (numberp article)
 358            (gnus-cache-request-article article group))
 359       (setq res (cons group article)
 360             clean-up t))
 361      ;; Use `head' function.
 362      ((fboundp head)
 363       (setq res (funcall head article (gnus-group-real-name group)
 364                          (nth 1 gnus-command-method))))
 365      ;; Use `article' function.
 366      (t
 367       (setq res (gnus-request-article article group)
 368             clean-up t)))
 369     (when clean-up
 370       (save-excursion
 371         (set-buffer nntp-server-buffer)
 372         (goto-char (point-min))
 373         (when (search-forward "\n\n" nil t)
 374           (delete-region (1- (point)) (point-max)))
 375         (nnheader-fold-continuation-lines)))
 376     res))
 377
 378 (defun gnus-request-body (article group)
 379   "Request the body of ARTICLE in GROUP."
 380   (let* ((gnus-command-method (gnus-find-method-for-group group))
 381          (head (gnus-get-function gnus-command-method 'request-body t))
 382          res clean-up)
 383     (cond
 384      ;; Check the cache.
 385      ((and gnus-use-cache
 386            (numberp article)
 387            (gnus-cache-request-article article group))
 388       (setq res (cons group article)
 389             clean-up t))
 390      ;; Use `head' function.
 391      ((fboundp head)
 392       (setq res (funcall head article (gnus-group-real-name group)
 393                          (nth 1 gnus-command-method))))
 394      ;; Use `article' function.
 395      (t
 396       (setq res (gnus-request-article article group)
 397             clean-up t)))
 398     (when clean-up
 399       (save-excursion
 400         (set-buffer nntp-server-buffer)
 401         (goto-char (point-min))
 402         (when (search-forward "\n\n" nil t)
 403           (delete-region (point-min) (1- (point))))))
 404     res))
 405
 406 (defun gnus-request-post (gnus-command-method)
 407   "Post the current buffer using GNUS-COMMAND-METHOD."
 408   (when (stringp gnus-command-method)
 409     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 410   (funcall (gnus-get-function gnus-command-method 'request-post)
 411            (nth 1 gnus-command-method)))
 412
 413 (defun gnus-request-scan (group gnus-command-method)
 414   "Request a SCAN being performed in GROUP from GNUS-COMMAND-METHOD.
 415 If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
 416   (let ((gnus-command-method
 417          (if group (gnus-find-method-for-group group) gnus-command-method))
 418         (gnus-inhibit-demon t)
 419         (mail-source-plugged gnus-plugged))
 420     (if (or gnus-plugged (not (gnus-agent-method-p gnus-command-method)))
 421         (funcall (gnus-get-function gnus-command-method 'request-scan)
 422                  (and group (gnus-group-real-name group))
 423                  (nth 1 gnus-command-method)))))
 424
 425 (defsubst gnus-request-update-info (info gnus-command-method)
 426   "Request that GNUS-COMMAND-METHOD update INFO."
 427   (when (stringp gnus-command-method)
 428     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 429   (when (gnus-check-backend-function
 430          'request-update-info (car gnus-command-method))
 431     (funcall (gnus-get-function gnus-command-method 'request-update-info)
 432              (gnus-group-real-name (gnus-info-group info))
 433              info (nth 1 gnus-command-method))))
 434
 435 (defun gnus-request-expire-articles (articles group &optional force)
 436   (let ((gnus-command-method (gnus-find-method-for-group group)))
 437     (funcall (gnus-get-function gnus-command-method 'request-expire-articles)
 438              articles (gnus-group-real-name group) (nth 1 gnus-command-method)
 439              force)))
 440
 441 (defun gnus-request-move-article
 442   (article group server accept-function &optional last)
 443   (let ((gnus-command-method (gnus-find-method-for-group group)))
 444     (funcall (gnus-get-function gnus-command-method 'request-move-article)
 445              article (gnus-group-real-name group)
 446              (nth 1 gnus-command-method) accept-function last)))
 447
 448 (defun gnus-request-accept-article (group &optional gnus-command-method last
 449                                           no-encode)
 450   ;; Make sure there's a newline at the end of the article.
 451   (when (stringp gnus-command-method)
 452     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 453   (when (and (not gnus-command-method)
 454              (stringp group))
 455     (setq gnus-command-method (gnus-group-name-to-method group)))
 456   (goto-char (point-max))
 457   (unless (bolp)
 458     (insert "\n"))
 459   (unless no-encode
 460     (save-restriction
 461       (message-narrow-to-head)
 462       (let ((mail-parse-charset message-default-charset))
 463         (mail-encode-encoded-word-buffer)))
 464     (message-encode-message-body))
 465   (let ((func (car (or gnus-command-method
 466                        (gnus-find-method-for-group group)))))
 467     (funcall (intern (format "%s-request-accept-article" func))
 468              (if (stringp group) (gnus-group-real-name group) group)
 469              (cadr gnus-command-method)
 470              last)))
 471
 472 (defun gnus-request-replace-article (article group buffer &optional no-encode)
 473   (unless no-encode
 474     (save-restriction
 475       (message-narrow-to-head)
 476       (let ((mail-parse-charset message-default-charset))
 477         (mail-encode-encoded-word-buffer)))
 478     (message-encode-message-body))
 479   (let ((func (car (gnus-group-name-to-method group))))
 480     (funcall (intern (format "%s-request-replace-article" func))
 481              article (gnus-group-real-name group) buffer)))
 482
 483 (defun gnus-request-associate-buffer (group)
 484   (let ((gnus-command-method (gnus-find-method-for-group group)))
 485     (funcall (gnus-get-function gnus-command-method 'request-associate-buffer)
 486              (gnus-group-real-name group))))
 487
 488 (defun gnus-request-restore-buffer (article group)
 489   "Request a new buffer restored to the state of ARTICLE."
 490   (let ((gnus-command-method (gnus-find-method-for-group group)))
 491     (funcall (gnus-get-function gnus-command-method 'request-restore-buffer)
 492              article (gnus-group-real-name group)
 493              (nth 1 gnus-command-method))))
 494
 495 (defun gnus-request-create-group (group &optional gnus-command-method args)
 496   (when (stringp gnus-command-method)
 497     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 498   (let ((gnus-command-method
 499          (or gnus-command-method (gnus-find-method-for-group group))))
 500     (funcall (gnus-get-function gnus-command-method 'request-create-group)
 501              (gnus-group-real-name group) (nth 1 gnus-command-method) args)))
 502
 503 (defun gnus-request-delete-group (group &optional force)
 504   (let ((gnus-command-method (gnus-find-method-for-group group)))
 505     (funcall (gnus-get-function gnus-command-method 'request-delete-group)
 506              (gnus-group-real-name group) force (nth 1 gnus-command-method))))
 507
 508 (defun gnus-request-rename-group (group new-name)
 509   (let ((gnus-command-method (gnus-find-method-for-group group)))
 510     (funcall (gnus-get-function gnus-command-method 'request-rename-group)
 511              (gnus-group-real-name group)
 512              (gnus-group-real-name new-name) (nth 1 gnus-command-method))))
 513
 514 (defun gnus-close-backends ()
 515   ;; Send a close request to all backends that support such a request.
 516   (let ((methods gnus-valid-select-methods)
 517         (gnus-inhibit-demon t)
 518         func gnus-command-method)
 519     (while (setq gnus-command-method (pop methods))
 520       (when (fboundp (setq func (intern
 521                                  (concat (car gnus-command-method)
 522                                          "-request-close"))))
 523         (funcall func)))))
 524
 525 (defun gnus-asynchronous-p (gnus-command-method)
 526   (let ((func (gnus-get-function gnus-command-method 'asynchronous-p t)))
 527     (when (fboundp func)
 528       (funcall func))))
 529
 530 (defun gnus-remove-denial (gnus-command-method)
 531   (when (stringp gnus-command-method)
 532     (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
 533   (let* ((elem (assoc gnus-command-method gnus-opened-servers))
 534          (status (cadr elem)))
 535     ;; If this hasn't been opened before, we add it to the list.
 536     (when (eq status 'denied)
 537       ;; Set the status of this server.
 538       (setcar (cdr elem) 'closed))))
 539
 540 (provide 'gnus-int)
 541
 542 ;;; gnus-int.el ends here