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

   1 ;;; gnus-sync.el --- synchronization facility for Gnus
   2
   3 ;; Copyright (C) 2010-2012  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-global-vars nil
 113   "List of global variables to be synchronized.
 114 You may want to sync `gnus-newsrc-last-checked-date' but pretty
 115 much any symbol is fair game.  You could additionally sync
 116 `gnus-newsrc-alist', `gnus-server-alist', `gnus-topic-topology',
 117 and `gnus-topic-alist'.  Also see `gnus-variable-list'."
 118   :group 'gnus-sync
 119   :type '(repeat (choice (variable :tag "A known variable")
 120                          (symbol :tag "Any symbol"))))
 121
 122 (defcustom gnus-sync-backend nil
 123   "The synchronization backend."
 124   :group 'gnus-sync
 125   :type '(radio (const :format "None" nil)
 126                 (list :tag "Sync server"
 127                       (const :format "LeSync Server API" lesync)
 128                       (string :tag "URL of a CouchDB database for API access"))
 129                 (string :tag "Sync to a file")))
 130
 131 (defvar gnus-sync-newsrc-loader nil
 132   "Carrier for newsrc data")
 133
 134 (defcustom gnus-sync-lesync-name (system-name)
 135   "The LeSync name for this machine."
 136   :group 'gnus-sync
 137   :version "24.3"
 138   :type 'string)
 139
 140 (defcustom gnus-sync-lesync-install-topics 'ask
 141   "Should LeSync install the recorded topics?"
 142   :group 'gnus-sync
 143   :version "24.3"
 144   :type '(choice (const :tag "Never Install" nil)
 145                  (const :tag "Always Install" t)
 146                  (const :tag "Ask Me Once" ask)))
 147
 148 (defvar gnus-sync-lesync-props-hash (make-hash-table :test 'equal)
 149   "LeSync props, keyed by group name")
 150
 151 (defvar gnus-sync-lesync-design-prefix "/_design/lesync"
 152   "The LeSync design prefix for CouchDB")
 153
 154 (defvar gnus-sync-lesync-security-object "/_security"
 155   "The LeSync security object for CouchDB")
 156
 157 (defun gnus-sync-lesync-parse ()
 158   "Parse the result of a LeSync request."
 159   (goto-char (point-min))
 160   (condition-case nil
 161       (when (search-forward-regexp "^$" nil t)
 162         (json-read))
 163     (error
 164      (gnus-message
 165       1
 166       "gnus-sync-lesync-parse: Could not read the LeSync response!")
 167      nil)))
 168
 169 (defun gnus-sync-lesync-call (url method headers &optional kvdata)
 170   "Make an access request to URL using KVDATA and METHOD.
 171 KVDATA must be an alist."
 172   (flet ((json-alist-p (list) (gnus-sync-json-alist-p list))) ; temp patch
 173     (let ((url-request-method method)
 174           (url-request-extra-headers headers)
 175           (url-request-data (if kvdata (json-encode kvdata) nil)))
 176       (with-current-buffer (url-retrieve-synchronously url)
 177         (let ((data (gnus-sync-lesync-parse)))
 178           (gnus-message 12 "gnus-sync-lesync-call: %s URL %s sent %S got %S"
 179                         method url `((headers . ,headers) (data ,kvdata)) data)
 180           (kill-buffer (current-buffer))
 181           data)))))
 182
 183 (defun gnus-sync-lesync-PUT (url headers &optional data)
 184   (gnus-sync-lesync-call url "PUT" headers data))
 185
 186 (defun gnus-sync-lesync-POST (url headers &optional data)
 187   (gnus-sync-lesync-call url "POST" headers data))
 188
 189 (defun gnus-sync-lesync-GET (url headers &optional data)
 190   (gnus-sync-lesync-call url "GET" headers data))
 191
 192 (defun gnus-sync-lesync-DELETE (url headers &optional data)
 193   (gnus-sync-lesync-call url "DELETE" headers data))
 194
 195 ;; this is not necessary with newer versions of json.el but 1.2 or older
 196 ;; (which are in Emacs 24.1 and earlier) need it
 197 (defun gnus-sync-json-alist-p (list)
 198   "Non-null if and only if LIST is an alist."
 199   (while (consp list)
 200     (setq list (if (consp (car list))
 201                    (cdr list)
 202                  'not-alist)))
 203   (null list))
 204
 205 ;; this is not necessary with newer versions of json.el but 1.2 or older
 206 ;; (which are in Emacs 24.1 and earlier) need it
 207 (defun gnus-sync-json-plist-p (list)
 208   "Non-null if and only if LIST is a plist."
 209   (while (consp list)
 210     (setq list (if (and (keywordp (car list))
 211                         (consp (cdr list)))
 212                    (cddr list)
 213                  'not-plist)))
 214   (null list))
 215
 216 ; (gnus-sync-lesync-setup "http://lesync.info:5984/tzz" "tzzadmin" "mypassword" "mysalt" t t)
 217 ; (gnus-sync-lesync-setup "http://lesync.info:5984/tzz")
 218
 219 (defun gnus-sync-lesync-setup (url &optional user password salt reader admin)
 220   (interactive "sEnter URL to set up: ")
 221   "Set up the LeSync database at URL.
 222 Install USER as a READER and/or an ADMIN in the security object
 223 under \"_security\", and in the CouchDB \"_users\" table using
 224 PASSWORD and SALT.  Only one USER is thus supported for now.
 225 When SALT is nil, a random one will be generated using `random'."
 226   (let* ((design-url (concat url gnus-sync-lesync-design-prefix))
 227          (security-object (concat url "/_security"))
 228          (user-record `((names . [,user]) (roles . [])))
 229          (couch-user-name (format "org.couchdb.user:%s" user))
 230          (salt (or salt (sha1 (format "%s" (random)))))
 231          (couch-user-record
 232           `((_id . ,couch-user-name)
 233             (type . user)
 234             (name . ,(format "%s" user))
 235             (roles . [])
 236             (salt . ,salt)
 237             (password_sha . ,(when password
 238                                (sha1
 239                                 (format "%s%s" password salt))))))
 240          (rev (progn
 241                 (gnus-sync-lesync-find-prop 'rev design-url design-url)
 242                 (gnus-sync-lesync-get-prop 'rev design-url)))
 243          (latest-func "function(head,req)
 244 {
 245   var tosend = [];
 246   var row;
 247   var ftime = (req.query['ftime'] || 0);
 248   while (row = getRow())
 249   {
 250     if (row.value['float-time'] > ftime)
 251     {
 252       var s = row.value['_id'];
 253       if (s) tosend.push('\"'+s.replace('\"', '\\\"')+'\"');
 254     }
 255   }
 256   send('['+tosend.join(',') + ']');
 257 }")
 258 ;; <key>read</key>
 259 ;; <dict>
 260 ;;   <key>de.alt.fan.ipod</key>
 261 ;;   <array>
 262 ;;       <integer>1</integer>
 263 ;;       <integer>2</integer>
 264 ;;       <dict>
 265 ;;           <key>start</key>
 266 ;;           <integer>100</integer>
 267 ;;           <key>length</key>
 268 ;;           <integer>100</integer>
 269 ;;       </dict>
 270 ;;   </array>
 271 ;; </dict>
 272          (xmlplistread-func "function(head, req) {
 273   var row;
 274   start({ 'headers': { 'Content-Type': 'text/xml' } });
 275
 276   send('<dict>');
 277   send('<key>read</key>');
 278   send('<dict>');
 279   while(row = getRow())
 280   {
 281     var read = row.value.read;
 282     if (read && read[0] && read[0] == 'invlist')
 283     {
 284       send('<key>'+row.key+'</key>');
 285       //send('<invlist>'+read+'</invlist>');
 286       send('<array>');
 287
 288       var from = 0;
 289       var flip = false;
 290
 291       for (var i = 1; i < read.length && read[i]; i++)
 292       {
 293         var cur = read[i];
 294         if (flip)
 295         {
 296           if (from == cur-1)
 297           {
 298             send('<integer>'+read[i]+'</integer>');
 299           }
 300           else
 301           {
 302             send('<dict>');
 303             send('<key>start</key>');
 304             send('<integer>'+from+'</integer>');
 305             send('<key>end</key>');
 306             send('<integer>'+(cur-1)+'</integer>');
 307             send('</dict>');
 308           }
 309
 310         }
 311         flip = ! flip;
 312         from = cur;
 313       }
 314       send('</array>');
 315     }
 316   }
 317
 318   send('</dict>');
 319   send('</dict>');
 320 }
 321 ")
 322          (subs-func "function(doc){emit([doc._id, doc.source], doc._rev);}")
 323          (revs-func "function(doc){emit(doc._id, doc._rev);}")
 324          (bytimesubs-func "function(doc)
 325 {emit([(doc['float-time']||0), doc._id], doc._rev);}")
 326          (bytime-func "function(doc)
 327 {emit([(doc['float-time']||0), doc._id], doc);}")
 328          (groups-func "function(doc){emit(doc._id, doc);}"))
 329     (and (if user
 330              (and (assq 'ok (gnus-sync-lesync-PUT
 331                              security-object
 332                              nil
 333                              (append (and reader
 334                                           (list `(readers . ,user-record)))
 335                                      (and admin
 336                                           (list `(admins . ,user-record))))))
 337                   (assq 'ok (gnus-sync-lesync-PUT
 338                              (concat (file-name-directory url)
 339                                      "_users/"
 340                                      couch-user-name)
 341                              nil
 342                              couch-user-record)))
 343            t)
 344          (assq 'ok (gnus-sync-lesync-PUT
 345                     design-url
 346                     nil
 347                     `(,@(when rev (list (cons '_rev rev)))
 348                       (lists . ((latest . ,latest-func)
 349                                 (xmlplistread . ,xmlplistread-func)))
 350                       (views . ((subs . ((map . ,subs-func)))
 351                                 (revs . ((map . ,revs-func)))
 352                                 (bytimesubs . ((map . ,bytimesubs-func)))
 353                                 (bytime . ((map . ,bytime-func)))
 354                                 (groups . ((map . ,groups-func)))))))))))
 355
 356 (defun gnus-sync-lesync-find-prop (prop url key)
 357   "Retrieve a PROPerty of a document KEY at URL.
 358 Calls `gnus-sync-lesync-set-prop'.
 359 For the 'rev PROP, uses '_rev against the document."
 360   (gnus-sync-lesync-set-prop
 361    prop key (cdr (assq (if (eq prop 'rev) '_rev prop)
 362                        (gnus-sync-lesync-GET url nil)))))
 363
 364 (defun gnus-sync-lesync-set-prop (prop key val)
 365   "Update the PROPerty of document KEY at URL to VAL.
 366 Updates `gnus-sync-lesync-props-hash'."
 367     (puthash (format "%s.%s" key prop) val gnus-sync-lesync-props-hash))
 368
 369 (defun gnus-sync-lesync-get-prop (prop key)
 370   "Get the PROPerty of KEY from `gnus-sync-lesync-props-hash'."
 371     (gethash (format "%s.%s" key prop) gnus-sync-lesync-props-hash))
 372
 373 (defun gnus-sync-deep-print (data)
 374   (let* ((print-quoted t)
 375          (print-readably t)
 376          (print-escape-multibyte nil)
 377          (print-escape-nonascii t)
 378          (print-length nil)
 379          (print-level nil)
 380          (print-circle nil)
 381          (print-escape-newlines t))
 382     (format "%S" data)))
 383
 384 (defun gnus-sync-newsrc-loader-builder (&optional only-modified)
 385   (let* ((entries (cdr gnus-newsrc-alist))
 386          entry name ret)
 387     (while entries
 388       (setq entry (pop entries)
 389             name (car entry))
 390       (when (gnus-grep-in-list name gnus-sync-newsrc-groups)
 391         (if only-modified
 392             (when (not (equal (gnus-sync-deep-print entry)
 393                               (gnus-sync-lesync-get-prop 'checksum name)))
 394               (gnus-message 9 "%s: add %s, it's modified"
 395                             "gnus-sync-newsrc-loader-builder" name)
 396               (push entry ret))
 397           (push entry ret))))
 398     ret))
 399
 400 ; (json-encode (gnus-sync-range2invlist '((1 . 47137) (47139 . 47714) 48129 48211 49231 49281 49342 49473 49475 49502)))
 401 (defun gnus-sync-range2invlist (ranges)
 402   (append '(invlist)
 403           (let ((ranges (delq nil ranges))
 404                 ret range from to)
 405             (while ranges
 406               (setq range (pop ranges))
 407               (if (atom range)
 408                   (setq from range
 409                         to range)
 410                 (setq from (car range)
 411                       to (cdr range)))
 412               (push from ret)
 413               (push (1+ to) ret))
 414             (reverse ret))))
 415
 416 ; (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))
 417 (defun gnus-sync-invlist2range (inv)
 418   (setq inv (append inv nil))
 419   (if (equal (format "%s" (car inv)) "invlist")
 420       (let ((i (cdr inv))
 421             (start 0)
 422             ret cur top flip)
 423         (while i
 424           (setq cur (pop i))
 425           (when flip
 426             (setq top (1- cur))
 427             (if (= start top)
 428                 (push start ret)
 429               (push (cons start top) ret)))
 430           (setq flip (not flip))
 431           (setq start cur))
 432         (reverse ret))
 433     inv))
 434
 435 (defun gnus-sync-position (search list &optional test)
 436   "Find the position of SEARCH in LIST using TEST, defaulting to `eq'."
 437   (let ((pos 0)
 438         (test (or test 'eq)))
 439     (while (and list (not (funcall test (car list) search)))
 440       (pop list)
 441       (incf pos))
 442     (if (funcall test (car list) search) pos nil)))
 443
 444 (defun gnus-sync-topic-group-position (group topic-name)
 445   (gnus-sync-position
 446    group (cdr (assoc topic-name gnus-topic-alist)) 'equal))
 447
 448 (defun gnus-sync-fix-topic-group-position (group topic-name position)
 449   (unless (equal position (gnus-sync-topic-group-position group topic-name))
 450     (let* ((loc "gnus-sync-fix-topic-group-position")
 451            (groups (delete group (cdr (assoc topic-name gnus-topic-alist))))
 452            (position (min position (1- (length groups))))
 453            (old (nth position groups)))
 454       (when (and old (not (equal old group)))
 455         (setf (nth position groups) group)
 456         (setcdr (assoc topic-name gnus-topic-alist)
 457                 (append groups (list old)))
 458         (gnus-message 9 "%s: %s moved to %d, swap with %s"
 459                       loc group position old)))))
 460
 461 (defun gnus-sync-lesync-pre-save-group-entry (url nentry &rest passed-props)
 462   (let* ((loc "gnus-sync-lesync-save-group-entry")
 463          (k (car nentry))
 464          (revision (gnus-sync-lesync-get-prop 'rev k))
 465          (sname gnus-sync-lesync-name)
 466          (topic (gnus-group-topic k))
 467          (topic-offset (gnus-sync-topic-group-position k topic))
 468          (sources (gnus-sync-lesync-get-prop 'source k)))
 469     ;; set the revision so we don't have a conflict
 470     `(,@(when revision
 471           (list (cons '_rev revision)))
 472       (_id . ,k)
 473       ;; the time we saved
 474       ,@passed-props
 475       ;; add our name to the sources list for this key
 476       (source ,@(if (member gnus-sync-lesync-name sources)
 477                     sources
 478                   (cons gnus-sync-lesync-name sources)))
 479       ,(cons 'level (nth 1 nentry))
 480       ,@(if topic (list (cons 'topic topic)) nil)
 481       ,@(if topic-offset (list (cons 'topic-offset topic-offset)) nil)
 482       ;; the read marks
 483       ,(cons 'read (gnus-sync-range2invlist (nth 2 nentry)))
 484       ;; the other marks
 485       ,@(delq nil (mapcar (lambda (mark-entry)
 486                             (gnus-message 12 "%s: prep param %s in %s"
 487                                           loc
 488                                           (car mark-entry)
 489                                           (nth 3 nentry))
 490                             (if (listp (cdr mark-entry))
 491                                 (cons (car mark-entry)
 492                                       (gnus-sync-range2invlist
 493                                        (cdr mark-entry)))
 494                               (progn    ; else this is not a list
 495                                 (gnus-message 9 "%s: non-list param %s in %s"
 496                                               loc
 497                                               (car mark-entry)
 498                                               (nth 3 nentry))
 499                                 nil)))
 500                           (nth 3 nentry))))))
 501
 502 (defun gnus-sync-lesync-post-save-group-entry (url entry)
 503   (let* ((loc "gnus-sync-lesync-post-save-group-entry")
 504          (k (cdr (assq 'id entry))))
 505     (cond
 506      ;; success!
 507      ((and (assq 'rev entry) (assq 'id entry))
 508       (progn
 509         (gnus-sync-lesync-set-prop 'rev k (cdr (assq 'rev entry)))
 510         (gnus-sync-lesync-set-prop 'checksum
 511                                    k
 512                                    (gnus-sync-deep-print
 513                                     (assoc k gnus-newsrc-alist)))
 514         (gnus-message 9 "%s: successfully synced %s to %s"
 515                       loc k url)))
 516      ;; specifically check for document conflicts
 517      ((equal "conflict" (format "%s" (cdr-safe (assq 'error entry))))
 518       (gnus-error
 519        1
 520        "%s: use `%s' to resolve the conflict synchronizing %s to %s: %s"
 521        loc "gnus-sync-read" k url (cdr (assq 'reason entry))))
 522      ;; generic errors
 523      ((assq 'error entry)
 524       (gnus-error 1 "%s: got error while synchronizing %s to %s: %s"
 525                   loc k url (cdr (assq 'reason entry))))
 526
 527      (t
 528       (gnus-message 2 "%s: unknown sync status after %s to %s: %S"
 529                     loc k url entry)))
 530     (assoc 'error entry)))
 531
 532 (defun gnus-sync-lesync-groups-builder (url)
 533   (let ((u (concat url gnus-sync-lesync-design-prefix "/_view/groups")))
 534     (cdr (assq 'rows (gnus-sync-lesync-GET u nil)))))
 535
 536 (defun gnus-sync-subscribe-group (name)
 537   "Subscribe to group NAME.  Returns NAME on success, nil otherwise."
 538   (gnus-subscribe-newsgroup name))
 539
 540 (defun gnus-sync-lesync-read-group-entry (url name entry &rest passed-props)
 541   "Read ENTRY information for NAME.  Returns NAME if successful.
 542 Skips entries whose sources don't contain
 543 `gnus-sync-lesync-name'.  When the alist PASSED-PROPS has a
 544 `subscribe-all' element that evaluates to true, we attempt to
 545 subscribe to unknown groups.  The user is also allowed to delete
 546 unwanted groups via the LeSync URL."
 547   (let* ((loc "gnus-sync-lesync-read-group-entry")
 548          (entry (gnus-sync-lesync-normalize-group-entry entry passed-props))
 549          (subscribe-all (cdr (assq 'subscribe-all passed-props)))
 550          (sources (cdr (assq 'source entry)))
 551          (rev (cdr (assq 'rev entry)))
 552          (in-sources (member gnus-sync-lesync-name sources))
 553          (known (assoc name gnus-newsrc-alist))
 554          cell)
 555     (unless known
 556       (if (and subscribe-all
 557                (y-or-n-p (format "Subscribe to group %s?" name)))
 558           (setq known (gnus-sync-subscribe-group name)
 559                 in-sources t)
 560         ;; else...
 561         (when (y-or-n-p (format "Delete group %s from server?" name))
 562           (if (equal name (gnus-sync-lesync-delete-group url name))
 563               (gnus-message 1 "%s: removed group %s from server %s"
 564                             loc name url)
 565             (gnus-error 1 "%s: could not remove group %s from server %s"
 566                         loc name url)))))
 567     (when known
 568       (unless in-sources
 569         (setq in-sources
 570               (y-or-n-p
 571                (format "Read group %s even though %s is not in sources %S?"
 572                        name gnus-sync-lesync-name (or sources ""))))))
 573     (when rev
 574       (gnus-sync-lesync-set-prop 'rev name rev))
 575
 576     ;; if the source matches AND we have this group
 577     (if (and known in-sources)
 578         (progn
 579           (gnus-message 10 "%s: reading LeSync entry %s, sources %S"
 580                         loc name sources)
 581           (while entry
 582             (setq cell (pop entry))
 583             (let ((k (car cell))
 584                   (val (cdr cell)))
 585               (gnus-sync-lesync-set-prop k name val)))
 586           name)
 587       ;; else...
 588       (unless known
 589         (gnus-message 5 "%s: ignoring entry %s, it wasn't subscribed.  %s"
 590                         loc name "Call `gnus-sync-read' with C-u to force it."))
 591       (unless in-sources
 592         (gnus-message 5 "%s: ignoring entry %s, %s not in sources %S"
 593                       loc name gnus-sync-lesync-name (or sources "")))
 594       nil)))
 595
 596 (defun gnus-sync-lesync-install-group-entry (name)
 597   (let* ((master (assoc name gnus-newsrc-alist))
 598          (old-topic-name (gnus-group-topic name))
 599          (old-topic (assoc old-topic-name gnus-topic-alist))
 600          (target-topic-name (gnus-sync-lesync-get-prop 'topic name))
 601          (target-topic-offset (gnus-sync-lesync-get-prop 'topic-offset name))
 602          (target-topic (assoc target-topic-name gnus-topic-alist))
 603          (loc "gnus-sync-lesync-install-group-entry"))
 604     (if master
 605         (progn
 606           (when (eq 'ask gnus-sync-lesync-install-topics)
 607             (setq gnus-sync-lesync-install-topics
 608                   (y-or-n-p "Install topics from LeSync?")))
 609           (when (and (eq t gnus-sync-lesync-install-topics)
 610                      target-topic-name)
 611             (if (equal old-topic-name target-topic-name)
 612                 (gnus-message 12 "%s: %s is already in topic %s"
 613                               loc name target-topic-name)
 614               ;; see `gnus-topic-move-group'
 615               (when (and old-topic target-topic)
 616                 (setcdr old-topic (gnus-delete-first name (cdr old-topic)))
 617                 (gnus-message 5 "%s: removing %s from topic %s"
 618                               loc name old-topic-name))
 619               (unless target-topic
 620                 (when (y-or-n-p (format "Create missing topic %s?"
 621                                         target-topic-name))
 622                   (gnus-topic-create-topic target-topic-name nil)
 623                   (setq target-topic (assoc target-topic-name
 624                                             gnus-topic-alist))))
 625               (if target-topic
 626                   (prog1
 627                       (nconc target-topic (list name))
 628                     (gnus-message 5 "%s: adding %s to topic %s"
 629                                   loc name (car target-topic))
 630                     (gnus-topic-enter-dribble))
 631                 (gnus-error 2 "%s: LeSync group %s can't go in missing topic %s"
 632                             loc name target-topic-name)))
 633             (when (and target-topic-offset target-topic)
 634               (gnus-sync-fix-topic-group-position
 635                name target-topic-name target-topic-offset)))
 636           ;; install the subscription level
 637           (when (gnus-sync-lesync-get-prop 'level name)
 638             (setf (nth 1 master) (gnus-sync-lesync-get-prop 'level name)))
 639           ;; install the read and other marks
 640           (setf (nth 2 master) (gnus-sync-lesync-get-prop 'read name))
 641           (setf (nth 3 master) (gnus-sync-lesync-get-prop 'marks name))
 642           (gnus-sync-lesync-set-prop 'checksum
 643                                      name
 644                                      (gnus-sync-deep-print master))
 645           nil)
 646       (gnus-error 1 "%s: invalid LeSync group %s" loc name)
 647       'invalid-name)))
 648
 649 ; (gnus-sync-lesync-delete-group (cdr gnus-sync-backend) "nntp+Gmane:gwene.org.slashdot")
 650
 651 (defun gnus-sync-lesync-delete-group (url name)
 652   "Returns NAME if successful deleting it from URL, an error otherwise."
 653   (interactive "sEnter URL to set up: \rsEnter group name: ")
 654   (let* ((u (concat (cadr gnus-sync-backend) "/" (url-hexify-string name)))
 655          (del (gnus-sync-lesync-DELETE
 656                u
 657                `(,@(when (gnus-sync-lesync-get-prop 'rev name)
 658                      (list (cons "If-Match"
 659                                  (gnus-sync-lesync-get-prop 'rev name))))))))
 660     (or (cdr (assq 'id del)) del)))
 661
 662 ;;; (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)))
 663
 664 (defun gnus-sync-lesync-normalize-group-entry (entry &optional passed-props)
 665   (let (ret
 666         marks
 667         cell)
 668     (setq entry (append passed-props entry))
 669     (while (setq cell (pop entry))
 670       (let ((k (car cell))
 671             (val (cdr cell)))
 672         (cond
 673          ((eq k 'read)
 674           (push (cons k (gnus-sync-invlist2range val)) ret))
 675          ;; we ignore these parameters
 676          ((member k '(_id subscribe-all _deleted_conflicts))
 677           nil)
 678          ((eq k '_rev)
 679           (push (cons 'rev val) ret))
 680          ((eq k 'source)
 681           (push (cons 'source (append val nil)) ret))
 682          ((or (eq k 'float-time)
 683               (eq k 'level)
 684               (eq k 'topic)
 685               (eq k 'topic-offset)
 686               (eq k 'read-time))
 687           (push (cons k val) ret))
 688 ;;; "How often have I said to you that when you have eliminated the
 689 ;;; impossible, whatever remains, however improbable, must be the
 690 ;;; truth?" --Sherlock Holmes
 691           ;; everything remaining must be a mark
 692           (t (push (cons k (gnus-sync-invlist2range val)) marks)))))
 693     (cons (cons 'marks marks) ret)))
 694
 695 (defun gnus-sync-save (&optional force)
 696 "Save the Gnus sync data to the backend.
 697 With a prefix, FORCE is set and all groups will be saved."
 698   (interactive "P")
 699   (cond
 700    ((and (listp gnus-sync-backend)
 701          (eq (nth 0 gnus-sync-backend) 'lesync)
 702          (stringp (nth 1 gnus-sync-backend)))
 703
 704     ;; refresh the revisions if we're forcing the save
 705     (when force
 706       (mapc (lambda (entry)
 707               (when (and (assq 'key entry)
 708                          (assq 'value entry))
 709                 (gnus-sync-lesync-set-prop
 710                  'rev
 711                  (cdr (assq 'key entry))
 712                  (cdr (assq 'value entry)))))
 713             ;; the revs view is key = name, value = rev
 714             (cdr (assq 'rows (gnus-sync-lesync-GET
 715                               (concat (nth 1 gnus-sync-backend)
 716                                       gnus-sync-lesync-design-prefix
 717                                       "/_view/revs")
 718                               nil)))))
 719
 720     (let* ((ftime (float-time))
 721            (url (nth 1 gnus-sync-backend))
 722            (entries
 723             (mapcar (lambda (entry)
 724                       (gnus-sync-lesync-pre-save-group-entry
 725                        (cadr gnus-sync-backend)
 726                        entry
 727                        (cons 'float-time ftime)))
 728                     (gnus-sync-newsrc-loader-builder (not force))))
 729            ;; when there are no entries, there's nothing to save
 730            (sync (if entries
 731                      (gnus-sync-lesync-POST
 732                       (concat url "/_bulk_docs")
 733                       '(("Content-Type" . "application/json"))
 734                       `((docs . ,(vconcat entries nil))))
 735                    (gnus-message
 736                     2 "gnus-sync-save: nothing to save to the LeSync backend")
 737                    nil)))
 738       (mapcar (lambda (e) (gnus-sync-lesync-post-save-group-entry url e))
 739               sync)))
 740    ((stringp gnus-sync-backend)
 741     (gnus-message 7 "gnus-sync-save: saving to backend %s" gnus-sync-backend)
 742     ;; populate gnus-sync-newsrc-loader from all but the first dummy
 743     ;; entry in gnus-newsrc-alist whose group matches any of the
 744     ;; gnus-sync-newsrc-groups
 745     ;; TODO: keep the old contents for groups we don't have!
 746     (let ((gnus-sync-newsrc-loader (gnus-sync-newsrc-loader-builder)))
 747       (with-temp-file gnus-sync-backend
 748         (progn
 749           (let ((coding-system-for-write gnus-ding-file-coding-system)
 750                 (standard-output (current-buffer)))
 751             (princ (format ";; -*- mode:emacs-lisp; coding: %s; -*-\n"
 752                            gnus-ding-file-coding-system))
 753             (princ ";; Gnus sync data v. 0.0.1\n")
 754             ;; TODO: replace with `gnus-sync-deep-print'
 755             (let* ((print-quoted t)
 756                    (print-readably t)
 757                    (print-escape-multibyte nil)
 758                    (print-escape-nonascii t)
 759                    (print-length nil)
 760                    (print-level nil)
 761                    (print-circle nil)
 762                    (print-escape-newlines t)
 763                    (variables (cons 'gnus-sync-newsrc-loader
 764                                     gnus-sync-global-vars))
 765                    variable)
 766               (while variables
 767                 (if (and (boundp (setq variable (pop variables)))
 768                            (symbol-value variable))
 769                     (progn
 770                       (princ "\n(setq ")
 771                       (princ (symbol-name variable))
 772                       (princ " '")
 773                       (prin1 (symbol-value variable))
 774                       (princ ")\n"))
 775                   (princ "\n;;; skipping empty variable ")
 776                   (princ (symbol-name variable)))))
 777             (gnus-message
 778              7
 779              "gnus-sync-save: stored variables %s and %d groups in %s"
 780              gnus-sync-global-vars
 781              (length gnus-sync-newsrc-loader)
 782              gnus-sync-backend)
 783
 784             ;; Idea from Dan Christensen <jdc@chow.mat.jhu.edu>
 785             ;; Save the .eld file with extra line breaks.
 786             (gnus-message 8 "gnus-sync-save: adding whitespace to %s"
 787                           gnus-sync-backend)
 788             (save-excursion
 789               (goto-char (point-min))
 790               (while (re-search-forward "^(\\|(\\\"" nil t)
 791                 (replace-match "\n\\&" t))
 792               (goto-char (point-min))
 793               (while (re-search-forward " $" nil t)
 794                 (replace-match "" t t))))))))
 795     ;; the pass-through case: gnus-sync-backend is not a known choice
 796     (nil)))
 797
 798 (defun gnus-sync-read (&optional subscribe-all)
 799   "Load the Gnus sync data from the backend.
 800 With a prefix, SUBSCRIBE-ALL is set and unknown groups will be subscribed."
 801   (interactive "P")
 802   (when gnus-sync-backend
 803     (gnus-message 7 "gnus-sync-read: loading from backend %s" gnus-sync-backend)
 804     (cond
 805      ((and (listp gnus-sync-backend)
 806            (eq (nth 0 gnus-sync-backend) 'lesync)
 807            (stringp (nth 1 gnus-sync-backend)))
 808       (let ((errored nil)
 809             name ftime)
 810         (mapc (lambda (entry)
 811                 (setq name (cdr (assq 'id entry)))
 812                 ;; set ftime the FIRST time through this loop, that
 813                 ;; way it reflects the time we FINISHED reading
 814                 (unless ftime (setq ftime (float-time)))
 815
 816                 (unless errored
 817                   (setq errored
 818                         (when (equal name
 819                                      (gnus-sync-lesync-read-group-entry
 820                                       (nth 1 gnus-sync-backend)
 821                                       name
 822                                       (cdr (assq 'value entry))
 823                                       `(read-time ,ftime)
 824                                       `(subscribe-all ,subscribe-all)))
 825                           (gnus-sync-lesync-install-group-entry
 826                            (cdr (assq 'id entry)))))))
 827               (gnus-sync-lesync-groups-builder (nth 1 gnus-sync-backend)))))
 828
 829      ((stringp gnus-sync-backend)
 830       ;; read data here...
 831       (if (or debug-on-error debug-on-quit)
 832           (load gnus-sync-backend nil t)
 833         (condition-case var
 834             (load gnus-sync-backend nil t)
 835           (error
 836            (error "Error in %s: %s" gnus-sync-backend (cadr var)))))
 837       (let ((valid-count 0)
 838             invalid-groups)
 839         (dolist (node gnus-sync-newsrc-loader)
 840           (if (gnus-gethash (car node) gnus-newsrc-hashtb)
 841               (progn
 842                 (incf valid-count)
 843                 (loop for store in (cdr node)
 844                       do (setf (nth (car store)
 845                                     (assoc (car node) gnus-newsrc-alist))
 846                                (cdr store))))
 847             (push (car node) invalid-groups)))
 848         (gnus-message
 849          7
 850          "gnus-sync-read: loaded %d groups (out of %d) from %s"
 851          valid-count (length gnus-sync-newsrc-loader)
 852          gnus-sync-backend)
 853         (when invalid-groups
 854           (gnus-message
 855            7
 856            "gnus-sync-read: skipped %d groups (out of %d) from %s"
 857            (length invalid-groups)
 858            (length gnus-sync-newsrc-loader)
 859            gnus-sync-backend)
 860           (gnus-message 9 "gnus-sync-read: skipped groups: %s"
 861                         (mapconcat 'identity invalid-groups ", ")))))
 862      (nil))
 863
 864     (gnus-message 9 "gnus-sync-read: remaking the newsrc hashtable")
 865     (gnus-make-hashtable-from-newsrc-alist)))
 866
 867 ;;;###autoload
 868 (defun gnus-sync-initialize ()
 869 "Initialize the Gnus sync facility."
 870   (interactive)
 871   (gnus-message 5 "Initializing the sync facility")
 872   (gnus-sync-install-hooks))
 873
 874 ;;;###autoload
 875 (defun gnus-sync-install-hooks ()
 876   "Install the sync hooks."
 877   (interactive)
 878   ;; (add-hook 'gnus-get-new-news-hook 'gnus-sync-read)
 879   ;; (add-hook 'gnus-read-newsrc-el-hook 'gnus-sync-read)
 880   (add-hook 'gnus-save-newsrc-hook 'gnus-sync-save))
 881
 882 (defun gnus-sync-unload-hook ()
 883   "Uninstall the sync hooks."
 884   (interactive)
 885   (remove-hook 'gnus-save-newsrc-hook 'gnus-sync-save))
 886
 887 (add-hook 'gnus-sync-unload-hook 'gnus-sync-unload-hook)
 888
 889 (when gnus-sync-backend (gnus-sync-initialize))
 890
 891 (provide 'gnus-sync)
 892
 893 ;;; gnus-sync.el ends here