lisp/gnus/gnus-cloud.el

   1 ;;; gnus-cloud.el --- storing and retrieving data via IMAP
   2
   3 ;; Copyright (C) 2014-2016 Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; Keywords: mail
   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 (require 'parse-time)
  29 (require 'nnimap)
  30
  31 (defgroup gnus-cloud nil
  32   "Syncing Gnus data via IMAP."
  33   :version "25.1"
  34   :group 'gnus)
  35
  36 (defcustom gnus-cloud-synced-files
  37   '(;;"~/.authinfo"
  38     "~/.authinfo.gpg"
  39     "~/.gnus.el"
  40     (:directory "~/News" :match ".*.SCORE\\'"))
  41   "List of file regexps that should be kept up-to-date via the cloud."
  42   :group 'gnus-cloud
  43   ;; FIXME this type does not match the default.  Nor does the documentation.
  44   :type '(repeat regexp))
  45
  46 (defvar gnus-cloud-group-name "*Emacs Cloud*")
  47 (defvar gnus-cloud-covered-servers nil)
  48
  49 (defvar gnus-cloud-version 1)
  50 (defvar gnus-cloud-sequence 1)
  51
  52 (defvar gnus-cloud-method nil
  53   "The IMAP select method used to store the cloud data.")
  54
  55 (defun gnus-cloud-make-chunk (elems)
  56   (with-temp-buffer
  57     (insert (format "Version %s\n" gnus-cloud-version))
  58     (insert (gnus-cloud-insert-data elems))
  59     (buffer-string)))
  60
  61 (defun gnus-cloud-insert-data (elems)
  62   (mm-with-unibyte-buffer
  63     (dolist (elem elems)
  64       (cond
  65        ((eq (plist-get elem :type) :file)
  66         (let (length data)
  67           (mm-with-unibyte-buffer
  68             (insert-file-contents-literally (plist-get elem :file-name))
  69             (setq length (buffer-size)
  70                   data (buffer-string)))
  71           (insert (format "(:type :file :file-name %S :timestamp %S :length %d)\n"
  72                           (plist-get elem :file-name)
  73                           (plist-get elem :timestamp)
  74                           length))
  75           (insert data)
  76           (insert "\n")))
  77        ((eq (plist-get elem :type) :data)
  78         (insert (format "(:type :data :name %S :length %d)\n"
  79                         (plist-get elem :name)
  80                         (with-current-buffer (plist-get elem :buffer)
  81                           (buffer-size))))
  82         (insert-buffer-substring (plist-get elem :buffer))
  83         (insert "\n"))
  84        ((eq (plist-get elem :type) :delete)
  85         (insert (format "(:type :delete :file-name %S)\n"
  86                         (plist-get elem :file-name))))))
  87     (gnus-cloud-encode-data)
  88     (buffer-string)))
  89
  90 (defun gnus-cloud-encode-data ()
  91   (call-process-region (point-min) (point-max) "gzip"
  92                        t (current-buffer) nil
  93                        "-c")
  94   (base64-encode-region (point-min) (point-max)))
  95
  96 (defun gnus-cloud-decode-data ()
  97   (base64-decode-region (point-min) (point-max))
  98   (call-process-region (point-min) (point-max) "gunzip"
  99                        t (current-buffer) nil
 100                        "-c"))
 101
 102 (defun gnus-cloud-parse-chunk ()
 103   (save-excursion
 104     (goto-char (point-min))
 105     (unless (looking-at "Version \\([0-9]+\\)")
 106       (error "Not a valid Cloud chunk in the current buffer"))
 107     (forward-line 1)
 108     (let ((version (string-to-number (match-string 1)))
 109           (data (buffer-substring (point) (point-max))))
 110       (mm-with-unibyte-buffer
 111         (insert data)
 112         (cond
 113          ((= version 1)
 114           (gnus-cloud-decode-data)
 115           (goto-char (point-min))
 116           (gnus-cloud-parse-version-1))
 117          (t
 118           (error "Unsupported Cloud chunk version %s" version)))))))
 119
 120 (defun gnus-cloud-parse-version-1 ()
 121   (let ((elems nil))
 122     (while (not (eobp))
 123       (while (and (not (eobp))
 124                   (not (looking-at "(:type")))
 125         (forward-line 1))
 126       (unless (eobp)
 127         (let ((spec (ignore-errors (read (current-buffer))))
 128               length)
 129           (when (and (consp spec)
 130                      (memq (plist-get spec :type) '(:file :data :delete)))
 131             (setq length (plist-get spec :length))
 132             (push (append spec
 133                           (list
 134                            :contents (buffer-substring (1+ (point))
 135                                                        (+ (point) 1 length))))
 136                   elems)
 137             (goto-char (+ (point) 1 length))))))
 138     (nreverse elems)))
 139
 140 (defun gnus-cloud-update-data (elems)
 141   (dolist (elem elems)
 142     (let ((type (plist-get elem :type)))
 143       (cond
 144        ((eq type :data)
 145         )
 146        ((eq type :delete)
 147         (gnus-cloud-delete-file (plist-get elem :file-name))
 148         )
 149        ((eq type :file)
 150         (gnus-cloud-update-file elem))
 151        (t
 152         (message "Unknown type %s; ignoring" type))))))
 153
 154 (defun gnus-cloud-update-file (elem)
 155   (let ((file-name (plist-get elem :file-name))
 156         (date (plist-get elem :timestamp))
 157         (contents (plist-get elem :contents)))
 158     (unless (gnus-cloud-file-covered-p file-name)
 159       (message "%s isn't covered by the cloud; ignoring" file-name))
 160     (when (or (not (file-exists-p file-name))
 161               (and (file-exists-p file-name)
 162                    (mm-with-unibyte-buffer
 163                      (insert-file-contents-literally file-name)
 164                      (not (equal (buffer-string) contents)))))
 165       (gnus-cloud-replace-file file-name date contents))))
 166
 167 (defun gnus-cloud-replace-file (file-name date new-contents)
 168   (mm-with-unibyte-buffer
 169     (insert new-contents)
 170     (when (file-exists-p file-name)
 171       (rename-file file-name (car (find-backup-file-name file-name))))
 172     (write-region (point-min) (point-max) file-name)
 173     (set-file-times file-name (parse-iso8601-time-string date))))
 174
 175 (defun gnus-cloud-delete-file (file-name)
 176   (unless (gnus-cloud-file-covered-p file-name)
 177     (message "%s isn't covered by the cloud; ignoring" file-name))
 178   (when (file-exists-p file-name)
 179     (rename-file file-name (car (find-backup-file-name file-name)))))
 180
 181 (defun gnus-cloud-file-covered-p (file-name)
 182   (let ((matched nil))
 183     (dolist (elem gnus-cloud-synced-files)
 184       (cond
 185        ((stringp elem)
 186         (when (equal elem file-name)
 187           (setq matched t)))
 188        ((consp elem)
 189         (when (and (equal (directory-file-name (plist-get elem :directory))
 190                           (directory-file-name (file-name-directory file-name)))
 191                    (string-match (plist-get elem :match)
 192                                  (file-name-nondirectory file-name)))
 193           (setq matched t)))))
 194     matched))
 195
 196 (defun gnus-cloud-all-files ()
 197   (let ((files nil))
 198     (dolist (elem gnus-cloud-synced-files)
 199       (cond
 200        ((stringp elem)
 201         (push elem files))
 202        ((consp elem)
 203         (dolist (file (directory-files (plist-get elem :directory)
 204                                        nil
 205                                        (plist-get elem :match)))
 206           (push (format "%s/%s"
 207                         (directory-file-name (plist-get elem :directory))
 208                         file)
 209                 files)))))
 210     (nreverse files)))
 211
 212 (defvar gnus-cloud-file-timestamps nil)
 213
 214 (defun gnus-cloud-files-to-upload (&optional full)
 215   (let ((files nil)
 216         timestamp)
 217     (dolist (file (gnus-cloud-all-files))
 218       (if (file-exists-p file)
 219           (when (setq timestamp (gnus-cloud-file-new-p file full))
 220             (push `(:type :file :file-name ,file :timestamp ,timestamp) files))
 221         (when (assoc file gnus-cloud-file-timestamps)
 222           (push `(:type :delete :file-name ,file) files))))
 223     (nreverse files)))
 224
 225 (defun gnus-cloud-file-new-p (file full)
 226   (let ((timestamp (format-time-string
 227                     "%FT%T%z" (nth 5 (file-attributes file))))
 228         (old (cadr (assoc file gnus-cloud-file-timestamps))))
 229     (when (or full
 230               (null old)
 231               (string< old timestamp))
 232       timestamp)))
 233
 234 (declare-function gnus-activate-group "gnus-start"
 235                   (group &optional scan dont-check method dont-sub-check))
 236 (declare-function gnus-subscribe-group "gnus-start"
 237                   (group &optional previous method))
 238
 239 (defun gnus-cloud-ensure-cloud-group ()
 240   (let ((method (if (stringp gnus-cloud-method)
 241                     (gnus-server-to-method gnus-cloud-method)
 242                   gnus-cloud-method)))
 243     (unless (or (gnus-active gnus-cloud-group-name)
 244                 (gnus-activate-group gnus-cloud-group-name nil nil
 245                                      gnus-cloud-method))
 246       (and (gnus-request-create-group gnus-cloud-group-name gnus-cloud-method)
 247            (gnus-activate-group gnus-cloud-group-name nil nil gnus-cloud-method)
 248            (gnus-subscribe-group gnus-cloud-group-name)))))
 249
 250 (defun gnus-cloud-upload-data (&optional full)
 251   (gnus-cloud-ensure-cloud-group)
 252   (with-temp-buffer
 253     (let ((elems (gnus-cloud-files-to-upload full)))
 254       (insert (format "Subject: (sequence: %d type: %s)\n"
 255                       gnus-cloud-sequence
 256                       (if full :full :partial)))
 257       (insert "From: nobody@invalid.com\n")
 258       (insert "\n")
 259       (insert (gnus-cloud-make-chunk elems))
 260       (when (gnus-request-accept-article gnus-cloud-group-name gnus-cloud-method
 261                                          t t)
 262         (setq gnus-cloud-sequence (1+ gnus-cloud-sequence))
 263         (gnus-cloud-add-timestamps elems)))))
 264
 265 (defun gnus-cloud-add-timestamps (elems)
 266   (dolist (elem elems)
 267     (let* ((file-name (plist-get elem :file-name))
 268            (old (assoc file-name gnus-cloud-file-timestamps)))
 269       (when old
 270         (setq gnus-cloud-file-timestamps
 271               (delq old gnus-cloud-file-timestamps)))
 272       (push (list file-name (plist-get elem :timestamp))
 273             gnus-cloud-file-timestamps))))
 274
 275 (defun gnus-cloud-available-chunks ()
 276   (gnus-activate-group gnus-cloud-group-name nil nil gnus-cloud-method)
 277   (let* ((group (gnus-group-full-name gnus-cloud-group-name gnus-cloud-method))
 278          (active (gnus-active group))
 279          headers head)
 280     (when (gnus-retrieve-headers (gnus-uncompress-range active) group)
 281       (with-current-buffer nntp-server-buffer
 282         (goto-char (point-min))
 283         (while (and (not (eobp))
 284                     (setq head (nnheader-parse-head)))
 285           (push head headers))))
 286     (sort (nreverse headers)
 287           (lambda (h1 h2)
 288             (> (gnus-cloud-chunk-sequence (mail-header-subject h1))
 289                (gnus-cloud-chunk-sequence (mail-header-subject h2)))))))
 290
 291 (defun gnus-cloud-chunk-sequence (string)
 292   (if (string-match "sequence: \\([0-9]+\\)" string)
 293       (string-to-number (match-string 1 string))
 294     0))
 295
 296 (defun gnus-cloud-prune-old-chunks (headers)
 297   (let ((headers (reverse headers))
 298         (found nil))
 299   (while (and headers
 300               (not found))
 301     (when (string-match "type: :full" (mail-header-subject (car headers)))
 302       (setq found t))
 303     (pop headers))
 304   ;; All the chunks that are older than the newest :full chunk can be
 305   ;; deleted.
 306   (when headers
 307     (gnus-request-expire-articles
 308      (mapcar (lambda (h)
 309                (mail-header-number h))
 310              (nreverse headers))
 311      (gnus-group-full-name gnus-cloud-group-name gnus-cloud-method)))))
 312
 313 (defun gnus-cloud-download-data ()
 314   (let ((articles nil)
 315         chunks)
 316     (dolist (header (gnus-cloud-available-chunks))
 317       (when (> (gnus-cloud-chunk-sequence (mail-header-subject header))
 318                gnus-cloud-sequence)
 319         (push (mail-header-number header) articles)))
 320     (when articles
 321       (nnimap-request-articles (nreverse articles) gnus-cloud-group-name)
 322       (with-current-buffer nntp-server-buffer
 323         (goto-char (point-min))
 324         (while (re-search-forward "^Version " nil t)
 325           (beginning-of-line)
 326           (push (gnus-cloud-parse-chunk) chunks)
 327           (forward-line 1))))))
 328
 329 (defun gnus-cloud-server-p (server)
 330   (member server gnus-cloud-covered-servers))
 331
 332 (defun gnus-cloud-collect-full-newsrc ()
 333   (let ((infos nil))
 334     (dolist (info (cdr gnus-newsrc-alist))
 335       (when (gnus-cloud-server-p
 336              (gnus-method-to-server
 337               (gnus-find-method-for-group (gnus-info-group info))))
 338         (push info infos)))
 339     ))
 340
 341 (provide 'gnus-cloud)
 342
 343 ;;; gnus-cloud.el ends here