code.delx.au - gnu-emacs/blob - lisp/gnus/gnus-sync.el

   1 ;;; gnus-sync.el --- synchronization facility for Gnus
   2
   3 ;; Copyright (C) 2010-2013 Free Software Foundation, Inc.
   4
   5 ;; Author: Ted Zlatanov <tzz@lifelogs.com>
   6 ;; Keywords: news synchronization nntp nnrss
   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 ;; This is the gnus-sync.el package.
  26
  27 ;; Put this in your startup file (~/.gnus.el for instance)
  28
  29 ;; possibilities for gnus-sync-backend:
  30 ;; Tramp over SSH: /ssh:user@host:/path/to/filename
  31 ;; ...or any other file Tramp and Emacs can handle...
  32
  33 ;; (setq gnus-sync-backend "/remote:/path.gpg" ; will use Tramp+EPA if loaded
  34 ;;       gnus-sync-global-vars '(gnus-newsrc-last-checked-date)
  35 ;;       gnus-sync-newsrc-groups '("nntp" "nnrss"))
  36 ;;       gnus-sync-newsrc-offsets '(2 3))
  37 ;; against a LeSync server (beware the vampire LeSync, who knows your newsrc)
  38
  39 ;; (setq gnus-sync-backend '(lesync "http://lesync.info:5984/tzz")
  40 ;;       gnus-sync-newsrc-groups '("nntp" "nnrss"))
  41
  42 ;; What's a LeSync server?
  43
  44 ;; 1. install CouchDB, set up a real server admin user, and create a
  45 ;; database, e.g. "tzz" and save the URL,
  46 ;; e.g. http://lesync.info:5984/tzz
  47
  48 ;; 2. run `M-: (gnus-sync-lesync-setup "http://lesync.info:5984/tzz" "tzzadmin" "mypassword" "mysalt" t t)'
  49
  50 ;;    (If you run it more than once, you have to remove the entry from
  51 ;;    _users yourself.  This is intentional.  This sets up a database
  52 ;;    admin for the "tzz" database, distinct from the server admin
  53 ;;    user in (1) above.)
  54
  55 ;; That's it, you can start using http://lesync.info:5984/tzz in your
  56 ;; gnus-sync-backend as a LeSync backend.  Fan fiction about the
  57 ;; vampire LeSync is welcome.
  58
  59 ;; You may not want to expose a CouchDB install to the Big Bad
  60 ;; Internet, especially if your love of all things furry would be thus
  61 ;; revealed.  Make sure it's not accessible by unauthorized users and
  62 ;; guests, at least.
  63
  64 ;; If you want to try it out, I will create a test DB for you under
  65 ;; http://lesync.info:5984/yourfavoritedbname
  66
  67 ;; TODO:
  68
  69 ;; - after gnus-sync-read, the message counts look wrong until you do
  70 ;;   `g'.  So it's not run automatically, you have to call it with M-x
  71 ;;   gnus-sync-read
  72
  73 ;; - use gnus-after-set-mark-hook and gnus-before-update-mark-hook to
  74 ;;   catch the mark updates
  75
  76 ;; - repositioning of groups within topic after a LeSync sync is a
  77 ;;   weird sort of bubble sort ("buttle" sort: the old entry ends up
  78 ;;   at the rear of the list); you will eventually end up with the
  79 ;;   right order after calling `gnus-sync-read' a bunch of times.
  80
  81 ;; - installing topics and groups is inefficient and annoying, lots of
  82 ;;   prompts could be avoided
  83
  84 ;;; Code:
  85
  86 (eval-when-compile (require 'cl))
  87 (require 'json)
  88 (require 'gnus)
  89 (require 'gnus-start)
  90 (require 'gnus-util)
  91
  92 (defvar gnus-topic-alist) ;; gnus-group.el
  93 (eval-when-compile
  94   (autoload 'gnus-group-topic "gnus-topic")
  95   (autoload 'gnus-topic-create-topic "gnus-topic" nil t)
  96   (autoload 'gnus-topic-enter-dribble "gnus-topic"))
  97
  98 (defgroup gnus-sync nil
  99   "The Gnus synchronization facility."
 100   :version "24.1"
 101   :group 'gnus)
 102
 103 (defcustom gnus-sync-newsrc-groups '("nntp" "nnrss")
 104   "List of groups to be synchronized in the gnus-newsrc-alist.
 105 The group names are matched, they don't have to be fully
 106 qualified.  Typically you would choose all of these.  That's the
 107 default because there is no active sync backend by default, so
 108 this setting is harmless until the user chooses a sync backend."
 109   :group 'gnus-sync
 110   :type '(repeat regexp))
 111
 112 (defcustom gnus-sync-newsrc-offsets '(2 3)
 113   "List of per-group data to be synchronized."
 114   :group 'gnus-sync
 115   :version "24.4"
 116   :type '(set (const :tag "Read ranges" 2)
 117               (const :tag "Marks" 3)))
 118
 119 (defcustom gnus-sync-global-vars nil
 120   "List of global variables to be synchronized.
 121 You may want to sync `gnus-newsrc-last-checked-date' but pretty
 122 much any symbol is fair game.  You could additionally sync
 123 `gnus-newsrc-alist', `gnus-server-alist', `gnus-topic-topology',
 124 and `gnus-topic-alist'.  Also see `gnus-variable-list'."
 125   :group 'gnus-sync
 126   :type '(repeat (choice (variable :tag "A known variable")
 127                          (symbol :tag "Any symbol"))))
 128
 129 (defcustom gnus-sync-backend nil
 130   "The synchronization backend."
 131   :group 'gnus-sync
 132   :type '(radio (const :format "None" nil)
 133                 (list :tag "Sync server"
 134                       (const :format "LeSync Server API" lesync)
 135                       (string :tag "URL of a CouchDB database for API access"))
 136                 (string :tag "Sync to a file")))
 137
 138 (defvar gnus-sync-newsrc-loader nil
 139   "Carrier for newsrc data")
 140
 141 (defcustom gnus-sync-file-encrypt-to nil
 142   "If non-nil, `epa-file-encrypt-to' is set from this for encrypting the Sync
 143   file."
 144   :group 'gnus-sync)
 145
 146 (defcustom gnus-sync-lesync-name (system-name)
 147   "The LeSync name for this machine."
 148   :group 'gnus-sync
 149   :version "24.3"
 150   :type 'string)
 151
 152 (defcustom gnus-sync-lesync-install-topics 'ask
 153   "Should LeSync install the recorded topics?"
 154   :group 'gnus-sync
 155   :version "24.3"
 156   :type '(choice (const :tag "Never Install" nil)
 157                  (const :tag "Always Install" t)
 158                  (const :tag "Ask Me Once" ask)))
 159
 160 (defvar gnus-sync-lesync-props-hash (make-hash-table :test 'equal)
 161   "LeSync props, keyed by group name")
 162
 163 (defvar gnus-sync-lesync-design-prefix "/_design/lesync"
 164   "The LeSync design prefix for CouchDB")
 165
 166 (defvar gnus-sync-lesync-security-object "/_security"
 167   "The LeSync security object for CouchDB")
 168
 169 (defun gnus-sync-lesync-parse ()
 170   "Parse the result of a LeSync request."
 171   (goto-char (point-min))
 172   (condition-case nil
 173       (when (search-forward-regexp "^$" nil t)
 174         (json-read))
 175     (error
 176      (gnus-message
 177       1
 178       "gnus-sync-lesync-parse: Could not read the LeSync response!")
 179      nil)))
 180
 181 (defun gnus-sync-lesync-call (url method headers &optional kvdata)
 182   "Make an access request to URL using KVDATA and METHOD.
 183 KVDATA must be an alist."
 184   (let ((url-request-method method)
 185         (url-request-extra-headers headers)
 186         (url-request-data (if kvdata (json-encode kvdata) nil)))
 187     (with-current-buffer (url-retrieve-synchronously url)
 188       (let ((data (gnus-sync-lesync-parse)))
 189         (gnus-message 12 "gnus-sync-lesync-call: %s URL %s sent %S got %S"
 190                       method url `((headers . ,headers) (data ,kvdata)) data)
 191         (kill-buffer (current-buffer))
 192         data))))
 193
 194 (defun gnus-sync-lesync-PUT (url headers &optional data)
 195   (gnus-sync-lesync-call url "PUT" headers data))
 196
 197 (defun gnus-sync-lesync-POST (url headers &optional data)
 198   (gnus-sync-lesync-call url "POST" headers data))
 199
 200 (defun gnus-sync-lesync-GET (url headers &optional data)
 201   (gnus-sync-lesync-call url "GET" headers data))
 202
 203 (defun gnus-sync-lesync-DELETE (url headers &optional data)
 204   (gnus-sync-lesync-call url "DELETE" headers data))
 205
 206 ;; this is not necessary with newer versions of json.el but 1.2 or older
 207 ;; (which are in Emacs 24.1 and earlier) need it
 208 (defun gnus-sync-json-alist-p (list)
 209   "Non-null if and only if LIST is an alist."
 210   (while (consp list)
 211     (setq list (if (consp (car list))
 212                    (cdr list)
 213                  'not-alist)))
 214   (null list))
 215
 216 ;; this is not necessary with newer versions of json.el but 1.2 or older
 217 ;; (which are in Emacs 24.1 and earlier) need it
 218 (defun gnus-sync-json-plist-p (list)
 219   "Non-null if and only if LIST is a plist."
 220   (while (consp list)
 221     (setq list (if (and (keywordp (car list))
 222                         (consp (cdr list)))
 223                    (cddr list)
 224                  'not-plist)))
 225   (null list))
 226
 227 ; (gnus-sync-lesync-setup "http://lesync.info:5984/tzz" "tzzadmin" "mypassword" "mysalt" t t)
 228 ; (gnus-sync-lesync-setup "http://lesync.info:5984/tzz")
 229
 230 (defun gnus-sync-lesync-setup (url &optional user password salt reader admin)
 231   (interactive "sEnter URL to set up: ")
 232   "Set up the LeSync database at URL.
 233 Install USER as a READER and/or an ADMIN in the security object
 234 under \"_security\", and in the CouchDB \"_users\" table using
 235 PASSWORD and SALT.  Only one USER is thus supported for now.
 236 When SALT is nil, a random one will be generated using `random'."
 237   (let* ((design-url (concat url gnus-sync-lesync-design-prefix))
 238          (security-object (concat url "/_security"))
 239          (user-record `((names . [,user]) (roles . [])))
 240          (couch-user-name (format "org.couchdb.user:%s" user))
 241          (salt (or salt (sha1 (format "%s" (random)))))
 242          (couch-user-record
 243           `((_id . ,couch-user-name)
 244             (type . user)
 245             (name . ,(format "%s" user))
 246             (roles . [])
 247             (salt . ,salt)
 248             (password_sha . ,(when password
 249                                (sha1
 250                                 (format "%s%s" password salt))))))
 251          (rev (progn
 252                 (gnus-sync-lesync-find-prop 'rev design-url design-url)
 253                 (gnus-sync-lesync-get-prop 'rev design-url)))
 254          (latest-func "function(head,req)
 255 {
 256   var tosend = [];
 257   var row;
 258   var ftime = (req.query['ftime'] || 0);
 259   while (row = getRow())
 260   {
 261     if (row.value['float-time'] > ftime)
 262     {
 263       var s = row.value['_id'];
 264       if (s) tosend.push('\"'+s.replace('\"', '\\\"')+'\"');
 265     }
 266   }
 267   send('['+tosend.join(',') + ']');
 268 }")
 269 ;; <key>read</key>
 270 ;; <dict>
 271 ;;   <key>de.alt.fan.ipod</key>
 272 ;;   <array>
 273 ;;       <integer>1</integer>
 274 ;;       <integer>2</integer>
 275 ;;       <dict>
 276 ;;           <key>start</key>
 277 ;;           <integer>100</integer>
 278 ;;           <key>length</key>
 279 ;;           <integer>100</integer>
 280 ;;       </dict>
 281 ;;   </array>
 282 ;; </dict>
 283          (xmlplistread-func "function(head, req) {
 284   var row;
 285   start({ 'headers': { 'Content-Type': 'text/xml' } });
 286
 287   send('<dict>');
 288   send('<key>read</key>');
 289   send('<dict>');
 290   while(row = getRow())
 291   {
 292     var read = row.value.read;
 293     if (read && read[0] && read[0] == 'invlist')
 294     {
 295       send('<key>'+row.key+'</key>');
 296       //send('<invlist>'+read+'</invlist>');
 297       send('<array>');
 298
 299       var from = 0;
 300       var flip = false;
 301
 302       for (var i = 1; i < read.length && read[i]; i++)
 303       {
 304         var cur = read[i];
 305         if (flip)
 306         {
 307           if (from == cur-1)
 308           {
 309             send('<integer>'+read[i]+'</integer>');
 310           }
 311           else
 312           {
 313             send('<dict>');
 314             send('<key>start</key>');
 315             send('<integer>'+from+'</integer>');
 316             send('<key>end</key>');
 317             send('<integer>'+(cur-1)+'</integer>');
 318             send('</dict>');
 319           }
 320
 321         }
 322         flip = ! flip;
 323         from = cur;
 324       }
 325       send('</array>');
 326     }
 327   }
 328
 329   send('</dict>');
 330   send('</dict>');
 331 }
 332 ")
 333          (subs-func "function(doc){emit([doc._id, doc.source], doc._rev);}")
 334          (revs-func "function(doc){emit(doc._id, doc._rev);}")
 335          (bytimesubs-func "function(doc)
 336 {emit([(doc['float-time']||0), doc._id], doc._rev);}")
 337          (bytime-func "function(doc)
 338 {emit([(doc['float-time']||0), doc._id], doc);}")
 339          (groups-func "function(doc){emit(doc._id, doc);}"))
 340     (and (if user
 341              (and (assq 'ok (gnus-sync-lesync-PUT
 342                              security-object
 343                              nil
 344                              (append (and reader
 345                                           (list `(readers . ,user-record)))
 346                                      (and admin
 347                                           (list `(admins . ,user-record))))))
 348                   (assq 'ok (gnus-sync-lesync-PUT
 349                              (concat (file-name-directory url)
 350                                      "_users/"
 351                                      couch-user-name)
 352                              nil
 353                              couch-user-record)))
 354            t)
 355          (assq 'ok (gnus-sync-lesync-PUT
 356                     design-url
 357                     nil
 358                     `(,@(when rev (list (cons '_rev rev)))
 359                       (lists . ((latest . ,latest-func)
 360                                 (xmlplistread . ,xmlplistread-func)))
 361                       (views . ((subs . ((map . ,subs-func)))
 362                                 (revs . ((map . ,revs-func)))
 363                                 (bytimesubs . ((map . ,bytimesubs-func)))
 364                                 (bytime . ((map . ,bytime-func)))
 365                                 (groups . ((map . ,groups-func)))))))))))
 366
 367 (defun gnus-sync-lesync-find-prop (prop url key)
 368   "Retrieve a PROPerty of a document KEY at URL.
 369 Calls `gnus-sync-lesync-set-prop'.
 370 For the 'rev PROP, uses '_rev against the document."
 371   (gnus-sync-lesync-set-prop
 372    prop key (cdr (assq (if (eq prop 'rev) '_rev prop)
 373                        (gnus-sync-lesync-GET url nil)))))
 374
 375 (defun gnus-sync-lesync-set-prop (prop key val)
 376   "Update the PROPerty of document KEY at URL to VAL.
 377 Updates `gnus-sync-lesync-props-hash'."
 378     (puthash (format "%s.%s" key prop) val gnus-sync-lesync-props-hash))
 379
 380 (defun gnus-sync-lesync-get-prop (prop key)
 381   "Get the PROPerty of KEY from `gnus-sync-lesync-props-hash'."
 382     (gethash (format "%s.%s" key prop) gnus-sync-lesync-props-hash))
 383
 384 (defun gnus-sync-deep-print (data)
 385   (let* ((print-quoted t)
 386          (print-readably t)
 387          (print-escape-multibyte nil)
 388          (print-escape-nonascii t)
 389          (print-length nil)
 390          (print-level nil)
 391          (print-circle nil)
 392          (print-escape-newlines t))
 393     (format "%S" data)))
 394
 395 (defun gnus-sync-newsrc-loader-builder (&optional only-modified)
 396   (let* ((entries (cdr gnus-newsrc-alist))
 397          entry name ret)
 398     (while entries
 399       (setq entry (pop entries)
 400             name (car entry))
 401       (when (gnus-grep-in-list name gnus-sync-newsrc-groups)
 402         (if only-modified
 403             (when (not (equal (gnus-sync-deep-print entry)
 404                               (gnus-sync-lesync-get-prop 'checksum name)))
 405               (gnus-message 9 "%s: add %s, it's modified"
 406                             "gnus-sync-newsrc-loader-builder" name)
 407               (push entry ret))
 408           (push entry ret))))
 409     ret))
 410
 411 ; (json-encode (gnus-sync-range2invlist '((1 . 47137) (47139 . 47714) 48129 48211 49231 49281 49342 49473 49475 49502)))
 412 (defun gnus-sync-range2invlist (ranges)
 413   (append '(invlist)
 414           (let ((ranges (delq nil ranges))
 415                 ret range from to)
 416             (while ranges
 417               (setq range (pop ranges))
 418               (if (atom range)
 419                   (setq from range
 420                         to range)
 421                 (setq from (car range)
 422                       to (cdr range)))
 423               (push from ret)
 424               (push (1+ to) ret))
 425             (reverse ret))))
 426
 427 ; (let* ((d '((1 . 47137) (47139 . 47714) 48129 48211 49231 49281 49342 49473 49475 49502)) (j (format "%S" (gnus-sync-invlist2range (gnus-sync-range2invlist d))))) (or (equal (format "%S" d) j) j))
 428 (defun gnus-sync-invlist2range (inv)
 429   (setq inv (append inv nil))
 430   (if (equal (format "%s" (car inv)) "invlist")
 431       (let ((i (cdr inv))
 432             (start 0)
 433             ret cur top flip)
 434         (while i
 435           (setq cur (pop i))
 436           (when flip
 437             (setq top (1- cur))
 438             (if (= start top)
 439                 (push start ret)
 440               (push (cons start top) ret)))
 441           (setq flip (not flip))
 442           (setq start cur))
 443         (reverse ret))
 444     inv))
 445
 446 (defun gnus-sync-position (search list &optional test)
 447   "Find the position of SEARCH in LIST using TEST, defaulting to `eq'."
 448   (let ((pos 0)
 449         (test (or test 'eq)))
 450     (while (and list (not (funcall test (car list) search)))
 451       (pop list)
 452       (incf pos))
 453     (if (funcall test (car list) search) pos nil)))
 454
 455 (defun gnus-sync-topic-group-position (group topic-name)
 456   (gnus-sync-position
 457    group (cdr (assoc topic-name gnus-topic-alist)) 'equal))
 458
 459 (defun gnus-sync-fix-topic-group-position (group topic-name position)
 460   (unless (equal position (gnus-sync-topic-group-position group topic-name))
 461     (let* ((loc "gnus-sync-fix-topic-group-position")
 462            (groups (delete group (cdr (assoc topic-name gnus-topic-alist))))
 463            (position (min position (1- (length groups))))
 464            (old (nth position groups)))
 465       (when (and old (not (equal old group)))
 466         (setf (nth position groups) group)
 467         (setcdr (assoc topic-name gnus-topic-alist)
 468                 (append groups (list old)))
 469         (gnus-message 9 "%s: %s moved to %d, swap with %s"
 470                       loc group position old)))))
 471
 472 (defun gnus-sync-lesync-pre-save-group-entry (url nentry &rest passed-props)
 473   (let* ((loc "gnus-sync-lesync-save-group-entry")
 474          (k (car nentry))
 475          (revision (gnus-sync-lesync-get-prop 'rev k))
 476          (sname gnus-sync-lesync-name)
 477          (topic (gnus-group-topic k))
 478          (topic-offset (gnus-sync-topic-group-position k topic))
 479          (sources (gnus-sync-lesync-get-prop 'source k)))
 480     ;; set the revision so we don't have a conflict
 481     `(,@(when revision
 482           (list (cons '_rev revision)))
 483       (_id . ,k)
 484       ;; the time we saved
 485       ,@passed-props
 486       ;; add our name to the sources list for this key
 487       (source ,@(if (member gnus-sync-lesync-name sources)
 488                     sources
 489                   (cons gnus-sync-lesync-name sources)))
 490       ,(cons 'level (nth 1 nentry))
 491       ,@(if topic (list (cons 'topic topic)) nil)
 492       ,@(if topic-offset (list (cons 'topic-offset topic-offset)) nil)
 493       ;; the read marks
 494       ,(cons 'read (gnus-sync-range2invlist (nth 2 nentry)))
 495       ;; the other marks
 496       ,@(delq nil (mapcar (lambda (mark-entry)
 497                             (gnus-message 12 "%s: prep param %s in %s"
 498                                           loc
 499                                           (car mark-entry)
 500                                           (nth 3 nentry))
 501                             (if (listp (cdr mark-entry))
 502                                 (cons (car mark-entry)
 503                                       (gnus-sync-range2invlist
 504                                        (cdr mark-entry)))
 505                               (progn    ; else this is not a list
 506                                 (gnus-message 9 "%s: non-list param %s in %s"
 507                                               loc
 508                                               (car mark-entry)
 509                                               (nth 3 nentry))
 510                                 nil)))
 511                           (nth 3 nentry))))))
 512
 513 (defun gnus-sync-lesync-post-save-group-entry (url entry)
 514   (let* ((loc "gnus-sync-lesync-post-save-group-entry")
 515          (k (cdr (assq 'id entry))))
 516     (cond
 517      ;; success!
 518      ((and (assq 'rev entry) (assq 'id entry))
 519       (progn
 520         (gnus-sync-lesync-set-prop 'rev k (cdr (assq 'rev entry)))
 521         (gnus-sync-lesync-set-prop 'checksum
 522                                    k
 523                                    (gnus-sync-deep-print
 524                                     (assoc k gnus-newsrc-alist)))
 525         (gnus-message 9 "%s: successfully synced %s to %s"
 526                       loc k url)))
 527      ;; specifically check for document conflicts
 528      ((equal "conflict" (format "%s" (cdr-safe (assq 'error entry))))
 529       (gnus-error
 530        1
 531        "%s: use `%s' to resolve the conflict synchronizing %s to %s: %s"
 532        loc "gnus-sync-read" k url (cdr (assq 'reason entry))))
 533      ;; generic errors
 534      ((assq 'error entry)
 535       (gnus-error 1 "%s: got error while synchronizing %s to %s: %s"
 536                   loc k url (cdr (assq 'reason entry))))
 537
 538      (t
 539       (gnus-message 2 "%s: unknown sync status after %s to %s: %S"
 540                     loc k url entry)))
 541     (assoc 'error entry)))
 542
 543 (defun gnus-sync-lesync-groups-builder (url)
 544   (let ((u (concat url gnus-sync-lesync-design-prefix "/_view/groups")))
 545     (cdr (assq 'rows (gnus-sync-lesync-GET u nil)))))
 546
 547 (defun gnus-sync-subscribe-group (name)
 548   "Subscribe to group NAME.  Returns NAME on success, nil otherwise."
 549   (gnus-subscribe-newsgroup name))
 550
 551 (defun gnus-sync-lesync-read-group-entry (url name entry &rest passed-props)
 552   "Read ENTRY information for NAME.  Returns NAME if successful.
 553 Skips entries whose sources don't contain
 554 `gnus-sync-lesync-name'.  When the alist PASSED-PROPS has a
 555 `subscribe-all' element that evaluates to true, we attempt to
 556 subscribe to unknown groups.  The user is also allowed to delete
 557 unwanted groups via the LeSync URL."
 558   (let* ((loc "gnus-sync-lesync-read-group-entry")
 559          (entry (gnus-sync-lesync-normalize-group-entry entry passed-props))
 560          (subscribe-all (cdr (assq 'subscribe-all passed-props)))
 561          (sources (cdr (assq 'source entry)))
 562          (rev (cdr (assq 'rev entry)))
 563          (in-sources (member gnus-sync-lesync-name sources))
 564          (known (assoc name gnus-newsrc-alist))
 565          cell)
 566     (unless known
 567       (if (and subscribe-all
 568                (y-or-n-p (format "Subscribe to group %s?" name)))
 569           (setq known (gnus-sync-subscribe-group name)
 570                 in-sources t)
 571         ;; else...
 572         (when (y-or-n-p (format "Delete group %s from server?" name))
 573           (if (equal name (gnus-sync-lesync-delete-group url name))
 574               (gnus-message 1 "%s: removed group %s from server %s"
 575                             loc name url)
 576             (gnus-error 1 "%s: could not remove group %s from server %s"
 577                         loc name url)))))
 578     (when known
 579       (unless in-sources
 580         (setq in-sources
 581               (y-or-n-p
 582                (format "Read group %s even though %s is not in sources %S?"
 583                        name gnus-sync-lesync-name (or sources ""))))))
 584     (when rev
 585       (gnus-sync-lesync-set-prop 'rev name rev))
 586
 587     ;; if the source matches AND we have this group
 588     (if (and known in-sources)
 589         (progn
 590           (gnus-message 10 "%s: reading LeSync entry %s, sources %S"
 591                         loc name sources)
 592           (while entry
 593             (setq cell (pop entry))
 594             (let ((k (car cell))
 595                   (val (cdr cell)))
 596               (gnus-sync-lesync-set-prop k name val)))
 597           name)
 598       ;; else...
 599       (unless known
 600         (gnus-message 5 "%s: ignoring entry %s, it wasn't subscribed.  %s"
 601                         loc name "Call `gnus-sync-read' with C-u to force it."))
 602       (unless in-sources
 603         (gnus-message 5 "%s: ignoring entry %s, %s not in sources %S"
 604                       loc name gnus-sync-lesync-name (or sources "")))
 605       nil)))
 606
 607 (defun gnus-sync-lesync-install-group-entry (name)
 608   (let* ((master (assoc name gnus-newsrc-alist))
 609          (old-topic-name (gnus-group-topic name))
 610          (old-topic (assoc old-topic-name gnus-topic-alist))
 611          (target-topic-name (gnus-sync-lesync-get-prop 'topic name))
 612          (target-topic-offset (gnus-sync-lesync-get-prop 'topic-offset name))
 613          (target-topic (assoc target-topic-name gnus-topic-alist))
 614          (loc "gnus-sync-lesync-install-group-entry"))
 615     (if master
 616         (progn
 617           (when (eq 'ask gnus-sync-lesync-install-topics)
 618             (setq gnus-sync-lesync-install-topics
 619                   (y-or-n-p "Install topics from LeSync?")))
 620           (when (and (eq t gnus-sync-lesync-install-topics)
 621                      target-topic-name)
 622             (if (equal old-topic-name target-topic-name)
 623                 (gnus-message 12 "%s: %s is already in topic %s"
 624                               loc name target-topic-name)
 625               ;; see `gnus-topic-move-group'
 626               (when (and old-topic target-topic)
 627                 (setcdr old-topic (gnus-delete-first name (cdr old-topic)))
 628                 (gnus-message 5 "%s: removing %s from topic %s"
 629                               loc name old-topic-name))
 630               (unless target-topic
 631                 (when (y-or-n-p (format "Create missing topic %s?"
 632                                         target-topic-name))
 633                   (gnus-topic-create-topic target-topic-name nil)
 634                   (setq target-topic (assoc target-topic-name
 635                                             gnus-topic-alist))))
 636               (if target-topic
 637                   (prog1
 638                       (nconc target-topic (list name))
 639                     (gnus-message 5 "%s: adding %s to topic %s"
 640                                   loc name (car target-topic))
 641                     (gnus-topic-enter-dribble))
 642                 (gnus-error 2 "%s: LeSync group %s can't go in missing topic %s"
 643                             loc name target-topic-name)))
 644             (when (and target-topic-offset target-topic)
 645               (gnus-sync-fix-topic-group-position
 646                name target-topic-name target-topic-offset)))
 647           ;; install the subscription level
 648           (when (gnus-sync-lesync-get-prop 'level name)
 649             (setf (nth 1 master) (gnus-sync-lesync-get-prop 'level name)))
 650           ;; install the read and other marks
 651           (setf (nth 2 master) (gnus-sync-lesync-get-prop 'read name))
 652           (setf (nth 3 master) (gnus-sync-lesync-get-prop 'marks name))
 653           (gnus-sync-lesync-set-prop 'checksum
 654                                      name
 655                                      (gnus-sync-deep-print master))
 656           nil)
 657       (gnus-error 1 "%s: invalid LeSync group %s" loc name)
 658       'invalid-name)))
 659
 660 ; (gnus-sync-lesync-delete-group (cdr gnus-sync-backend) "nntp+Gmane:gwene.org.slashdot")
 661
 662 (defun gnus-sync-lesync-delete-group (url name)
 663   "Returns NAME if successful deleting it from URL, an error otherwise."
 664   (interactive "sEnter URL to set up: \rsEnter group name: ")
 665   (let* ((u (concat (cadr gnus-sync-backend) "/" (url-hexify-string name)))
 666          (del (gnus-sync-lesync-DELETE
 667                u
 668                `(,@(when (gnus-sync-lesync-get-prop 'rev name)
 669                      (list (cons "If-Match"
 670                                  (gnus-sync-lesync-get-prop 'rev name))))))))
 671     (or (cdr (assq 'id del)) del)))
 672
 673 ;;; (gnus-sync-lesync-normalize-group-entry '((subscribe . ["invlist"]) (read . ["invlist"]) (topic-offset . 20) (topic . "news") (level . 6) (source . ["a" "b"]) (float-time . 1319671237.099285) (_rev . "10-edf5107f41e5e6f7f6629d1c0ee172f7") (_id . "nntp+news.net:alt.movies")) '((read-time 1319672156.486414) (subscribe-all nil)))
 674
 675 (defun gnus-sync-lesync-normalize-group-entry (entry &optional passed-props)
 676   (let (ret
 677         marks
 678         cell)
 679     (setq entry (append passed-props entry))
 680     (while (setq cell (pop entry))
 681       (let ((k (car cell))
 682             (val (cdr cell)))
 683         (cond
 684          ((eq k 'read)
 685           (push (cons k (gnus-sync-invlist2range val)) ret))
 686          ;; we ignore these parameters
 687          ((member k '(_id subscribe-all _deleted_conflicts))
 688           nil)
 689          ((eq k '_rev)
 690           (push (cons 'rev val) ret))
 691          ((eq k 'source)
 692           (push (cons 'source (append val nil)) ret))
 693          ((or (eq k 'float-time)
 694               (eq k 'level)
 695               (eq k 'topic)
 696               (eq k 'topic-offset)
 697               (eq k 'read-time))
 698           (push (cons k val) ret))
 699 ;;; "How often have I said to you that when you have eliminated the
 700 ;;; impossible, whatever remains, however improbable, must be the
 701 ;;; truth?" --Sherlock Holmes
 702           ;; everything remaining must be a mark
 703           (t (push (cons k (gnus-sync-invlist2range val)) marks)))))
 704     (cons (cons 'marks marks) ret)))
 705
 706 (defun gnus-sync-save (&optional force)
 707 "Save the Gnus sync data to the backend.
 708 With a prefix, FORCE is set and all groups will be saved."
 709   (interactive "P")
 710   (cond
 711    ((and (listp gnus-sync-backend)
 712          (eq (nth 0 gnus-sync-backend) 'lesync)
 713          (stringp (nth 1 gnus-sync-backend)))
 714
 715     ;; refresh the revisions if we're forcing the save
 716     (when force
 717       (mapc (lambda (entry)
 718               (when (and (assq 'key entry)
 719                          (assq 'value entry))
 720                 (gnus-sync-lesync-set-prop
 721                  'rev
 722                  (cdr (assq 'key entry))
 723                  (cdr (assq 'value entry)))))
 724             ;; the revs view is key = name, value = rev
 725             (cdr (assq 'rows (gnus-sync-lesync-GET
 726                               (concat (nth 1 gnus-sync-backend)
 727                                       gnus-sync-lesync-design-prefix
 728                                       "/_view/revs")
 729                               nil)))))
 730
 731     (let* ((ftime (float-time))
 732            (url (nth 1 gnus-sync-backend))
 733            (entries
 734             (mapcar (lambda (entry)
 735                       (gnus-sync-lesync-pre-save-group-entry
 736                        (cadr gnus-sync-backend)
 737                        entry
 738                        (cons 'float-time ftime)))
 739                     (gnus-sync-newsrc-loader-builder (not force))))
 740            ;; when there are no entries, there's nothing to save
 741            (sync (if entries
 742                      (gnus-sync-lesync-POST
 743                       (concat url "/_bulk_docs")
 744                       '(("Content-Type" . "application/json"))
 745                       `((docs . ,(vconcat entries nil))))
 746                    (gnus-message
 747                     2 "gnus-sync-save: nothing to save to the LeSync backend")
 748                    nil)))
 749       (mapcar (lambda (e) (gnus-sync-lesync-post-save-group-entry url e))
 750               sync)))
 751    ((stringp gnus-sync-backend)
 752     (gnus-message 7 "gnus-sync-save: saving to backend %s" gnus-sync-backend)
 753     ;; populate gnus-sync-newsrc-loader from all but the first dummy
 754     ;; entry in gnus-newsrc-alist whose group matches any of the
 755     ;; gnus-sync-newsrc-groups
 756     ;; TODO: keep the old contents for groups we don't have!
 757     (let ((gnus-sync-newsrc-loader
 758            (loop for entry in (cdr gnus-newsrc-alist)
 759                  when (gnus-grep-in-list
 760                        (car entry)     ;the group name
 761                        gnus-sync-newsrc-groups)
 762                  collect (cons (car entry)
 763                                (mapcar (lambda (offset)
 764                                          (cons offset (nth offset entry)))
 765                                        gnus-sync-newsrc-offsets)))))
 766       (with-temp-file gnus-sync-backend
 767         (progn
 768           (let ((coding-system-for-write gnus-ding-file-coding-system)
 769                 (standard-output (current-buffer)))
 770             (when gnus-sync-file-encrypt-to
 771               (set (make-local-variable 'epa-file-encrypt-to)
 772                    gnus-sync-file-encrypt-to))
 773             (princ (format ";; -*- mode:emacs-lisp; coding: %s; -*-\n"
 774                            gnus-ding-file-coding-system))
 775             (princ ";; Gnus sync data v. 0.0.1\n")
 776             ;; TODO: replace with `gnus-sync-deep-print'
 777             (let* ((print-quoted t)
 778                    (print-readably t)
 779                    (print-escape-multibyte nil)
 780                    (print-escape-nonascii t)
 781                    (print-length nil)
 782                    (print-level nil)
 783                    (print-circle nil)
 784                    (print-escape-newlines t)
 785                    (variables (cons 'gnus-sync-newsrc-loader
 786                                     gnus-sync-global-vars))
 787                    variable)
 788               (while variables
 789                 (if (and (boundp (setq variable (pop variables)))
 790                            (symbol-value variable))
 791                     (progn
 792                       (princ "\n(setq ")
 793                       (princ (symbol-name variable))
 794                       (princ " '")
 795                       (prin1 (symbol-value variable))
 796                       (princ ")\n"))
 797                   (princ "\n;;; skipping empty variable ")
 798                   (princ (symbol-name variable)))))
 799             (gnus-message
 800              7
 801              "gnus-sync-save: stored variables %s and %d groups in %s"
 802              gnus-sync-global-vars
 803              (length gnus-sync-newsrc-loader)
 804              gnus-sync-backend)
 805
 806             ;; Idea from Dan Christensen <jdc@chow.mat.jhu.edu>
 807             ;; Save the .eld file with extra line breaks.
 808             (gnus-message 8 "gnus-sync-save: adding whitespace to %s"
 809                           gnus-sync-backend)
 810             (save-excursion
 811               (goto-char (point-min))
 812               (while (re-search-forward "^(\\|(\\\"" nil t)
 813                 (replace-match "\n\\&" t))
 814               (goto-char (point-min))
 815               (while (re-search-forward " $" nil t)
 816                 (replace-match "" t t))))))))
 817     ;; the pass-through case: gnus-sync-backend is not a known choice
 818     (nil)))
 819
 820 (defun gnus-sync-read (&optional subscribe-all)
 821   "Load the Gnus sync data from the backend.
 822 With a prefix, SUBSCRIBE-ALL is set and unknown groups will be subscribed."
 823   (interactive "P")
 824   (when gnus-sync-backend
 825     (gnus-message 7 "gnus-sync-read: loading from backend %s" gnus-sync-backend)
 826     (cond
 827      ((and (listp gnus-sync-backend)
 828            (eq (nth 0 gnus-sync-backend) 'lesync)
 829            (stringp (nth 1 gnus-sync-backend)))
 830       (let ((errored nil)
 831             name ftime)
 832         (mapc (lambda (entry)
 833                 (setq name (cdr (assq 'id entry)))
 834                 ;; set ftime the FIRST time through this loop, that
 835                 ;; way it reflects the time we FINISHED reading
 836                 (unless ftime (setq ftime (float-time)))
 837
 838                 (unless errored
 839                   (setq errored
 840                         (when (equal name
 841                                      (gnus-sync-lesync-read-group-entry
 842                                       (nth 1 gnus-sync-backend)
 843                                       name
 844                                       (cdr (assq 'value entry))
 845                                       `(read-time ,ftime)
 846                                       `(subscribe-all ,subscribe-all)))
 847                           (gnus-sync-lesync-install-group-entry
 848                            (cdr (assq 'id entry)))))))
 849               (gnus-sync-lesync-groups-builder (nth 1 gnus-sync-backend)))))
 850
 851      ((stringp gnus-sync-backend)
 852       ;; read data here...
 853       (if (or debug-on-error debug-on-quit)
 854           (load gnus-sync-backend nil t)
 855         (condition-case var
 856             (load gnus-sync-backend nil t)
 857           (error
 858            (error "Error in %s: %s" gnus-sync-backend (cadr var)))))
 859       (let ((valid-count 0)
 860             invalid-groups)
 861         (dolist (node gnus-sync-newsrc-loader)
 862           (if (gnus-gethash (car node) gnus-newsrc-hashtb)
 863               (progn
 864                 (incf valid-count)
 865                 (loop for store in (cdr node)
 866                       do (setf (nth (car store)
 867                                     (assoc (car node) gnus-newsrc-alist))
 868                                (cdr store))))
 869             (push (car node) invalid-groups)))
 870         (gnus-message
 871          7
 872          "gnus-sync-read: loaded %d groups (out of %d) from %s"
 873          valid-count (length gnus-sync-newsrc-loader)
 874          gnus-sync-backend)
 875         (when invalid-groups
 876           (gnus-message
 877            7
 878            "gnus-sync-read: skipped %d groups (out of %d) from %s"
 879            (length invalid-groups)
 880            (length gnus-sync-newsrc-loader)
 881            gnus-sync-backend)
 882           (gnus-message 9 "gnus-sync-read: skipped groups: %s"
 883                         (mapconcat 'identity invalid-groups ", ")))))
 884      (nil))
 885
 886     (gnus-message 9 "gnus-sync-read: remaking the newsrc hashtable")
 887     (gnus-make-hashtable-from-newsrc-alist)))
 888
 889 ;;;###autoload
 890 (defun gnus-sync-initialize ()
 891 "Initialize the Gnus sync facility."
 892   (interactive)
 893   (gnus-message 5 "Initializing the sync facility")
 894   (gnus-sync-install-hooks))
 895
 896 ;;;###autoload
 897 (defun gnus-sync-install-hooks ()
 898   "Install the sync hooks."
 899   (interactive)
 900   ;; (add-hook 'gnus-get-new-news-hook 'gnus-sync-read)
 901   ;; (add-hook 'gnus-read-newsrc-el-hook 'gnus-sync-read)
 902   (add-hook 'gnus-save-newsrc-hook 'gnus-sync-save))
 903
 904 (defun gnus-sync-unload-hook ()
 905   "Uninstall the sync hooks."
 906   (interactive)
 907   (remove-hook 'gnus-save-newsrc-hook 'gnus-sync-save))
 908
 909 (add-hook 'gnus-sync-unload-hook 'gnus-sync-unload-hook)
 910
 911 (when gnus-sync-backend (gnus-sync-initialize))
 912
 913 (provide 'gnus-sync)
 914
 915 ;;; gnus-sync.el ends here