lisp/shadowfile.el

   1 ;;; shadowfile.el --- automatic file copying
   2
   3 ;; Copyright (C) 1993, 1994, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6 ;; Author: Boris Goldowsky <boris@gnu.org>
   7 ;; Keywords: comm files
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 3, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;;  This package helps you to keep identical copies of files in more than one
  29 ;;  place - possibly on different machines.  When you save a file, it checks
  30 ;;  whether it is on the list of files with "shadows", and if so, it tries to
  31 ;;  copy it when you exit emacs (or use the shadow-copy-files command).
  32
  33 ;; Installation & Use:
  34
  35 ;;  Add clusters (if necessary) and file groups with shadow-define-cluster,
  36 ;;  shadow-define-literal-group, and shadow-define-regexp-group (see the
  37 ;;  documentation for these functions for information on how and when to use
  38 ;;  them).  After doing this once, everything should be automatic.
  39
  40 ;;  The lists of clusters and shadows are saved in a file called .shadows,
  41 ;;  so that they can be remembered from one emacs session to another, even
  42 ;;  (as much as possible) if the emacs session terminates abnormally.  The
  43 ;;  files needing to be copied are stored in .shadow_todo; if a file cannot
  44 ;;  be copied for any reason, it will stay on the list to be tried again
  45 ;;  next time.  The .shadows file should itself have shadows on all your
  46 ;;  accounts so that the information in it is consistent everywhere, but
  47 ;;  .shadow_todo is local information and should have no shadows.
  48
  49 ;;  If you do not want to copy a particular file, you can answer "no" and
  50 ;;  be asked again next time you hit C-x 4 s or exit emacs.  If you do not
  51 ;;  want to be asked again, use shadow-cancel, and you will not be asked
  52 ;;  until you change the file and save it again.  If you do not want to
  53 ;;  shadow that file ever again, you can edit it out of the .shadows
  54 ;;  buffer.  Anytime you edit the .shadows buffer, you must type M-x
  55 ;;  shadow-read-files to load in the new information, or your changes will
  56 ;;  be overwritten!
  57
  58 ;; Bugs & Warnings:
  59 ;;
  60 ;;  - It is bad to have two emacses both running shadowfile at the same
  61 ;;  time.  It tries to detect this condition, but is not always successful.
  62 ;;
  63 ;;  - You have to be careful not to edit a file in two locations
  64 ;;  before shadowfile has had a chance to copy it; otherwise
  65 ;;  "updating shadows" will overwrite one of the changed versions.
  66 ;;
  67 ;;  - It ought to check modification times of both files to make sure
  68 ;;  it is doing the right thing.  This will have to wait until
  69 ;;  file-newer-than-file-p works between machines.
  70 ;;
  71 ;;  - It will not make directories for you, it just fails to copy files
  72 ;;  that belong in non-existent directories.
  73 ;;
  74 ;;  Please report any bugs to me (boris@gnu.org).  Also let me know
  75 ;;  if you have suggestions or would like to be informed of updates.
  76
  77
  78 ;;; Code:
  79
  80 (require 'ange-ftp)
  81
  82 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  83 ;;; Variables
  84 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  85
  86 (defgroup shadow nil
  87   "Automatic file copying when saving a file."
  88   :prefix "shadow-"
  89   :link '(emacs-commentary-link "shadowfile")
  90   :group 'files)
  91
  92 (defcustom shadow-noquery nil
  93   "*If t, always copy shadow files without asking.
  94 If nil \(the default), always ask.  If not nil and not t, ask only if there
  95 is no buffer currently visiting the file."
  96   :type '(choice (const t) (const nil) (other :tag "Ask if no buffer" maybe))
  97   :group 'shadow)
  98
  99 (defcustom shadow-inhibit-message nil
 100   "*If non-nil, do not display a message when a file needs copying."
 101   :type 'boolean
 102   :group 'shadow)
 103
 104 (defcustom shadow-inhibit-overload nil
 105   "If non-nil, shadowfile won't redefine \\[save-buffers-kill-emacs].
 106 Normally it overloads the function `save-buffers-kill-emacs' to check for
 107 files that have been changed and need to be copied to other systems."
 108   :type 'boolean
 109   :group 'shadow)
 110
 111 (defcustom shadow-info-file nil
 112   "File to keep shadow information in.
 113 The `shadow-info-file' should be shadowed to all your accounts to
 114 ensure consistency.  Default: ~/.shadows"
 115   :type '(choice (const nil) file)
 116   :group 'shadow)
 117
 118 (defcustom shadow-todo-file nil
 119   "File to store the list of uncopied shadows in.
 120 This means that if a remote system is down, or for any reason you cannot or
 121 decide not to copy your shadow files at the end of one Emacs session, it will
 122 remember and ask you again in your next Emacs session.
 123 This file must NOT be shadowed to any other system, it is host-specific.
 124 Default: ~/.shadow_todo"
 125   :type '(choice (const nil) file)
 126   :group 'shadow)
 127
 128
 129 ;;; The following two variables should in most cases initialize themselves
 130 ;;; correctly.  They are provided as variables in case the defaults are wrong
 131 ;;; on your machine \(and for efficiency).
 132
 133 (defvar shadow-system-name (system-name)
 134   "The complete hostname of this machine.")
 135
 136 (defvar shadow-homedir nil
 137   "Your home directory on this machine.")
 138
 139 ;;;
 140 ;;; Internal variables whose values are stored in the info and todo files:
 141 ;;;
 142
 143 (defvar shadow-clusters nil
 144   "List of host clusters \(see `shadow-define-cluster').")
 145
 146 (defvar shadow-literal-groups nil
 147   "List of files that are shared between hosts.
 148 This list contains shadow structures with literal filenames, created by
 149 `shadow-define-literal-group'.")
 150
 151 (defvar shadow-regexp-groups nil
 152   "List of file types that are shared between hosts.
 153 This list contains shadow structures with regexps matching filenames,
 154 created by `shadow-define-regexp-group'.")
 155
 156 ;;;
 157 ;;; Other internal variables:
 158 ;;;
 159
 160 (defvar shadow-files-to-copy nil)       ; List of files that need to
 161                                         ; be copied to remote hosts.
 162
 163 (defvar shadow-hashtable nil)           ; for speed
 164
 165 (defvar shadow-info-buffer nil)         ; buf visiting shadow-info-file
 166 (defvar shadow-todo-buffer nil)         ; buf visiting shadow-todo-file
 167
 168 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 169 ;;; Syntactic sugar; General list and string manipulation
 170 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 171
 172 (defun shadow-union (a b)
 173   "Add members of list A to list B if not equal to items already in B."
 174   (if (null a)
 175       b
 176     (if (member (car a) b)
 177         (shadow-union (cdr a) b)
 178       (shadow-union (cdr a) (cons (car a) b)))))
 179
 180 (defun shadow-find (func list)
 181   "If FUNC applied to some element of LIST is non-nil, return first such element."
 182   (while (and list (not (funcall func (car list))))
 183     (setq list (cdr list)))
 184   (car list))
 185
 186 (defun shadow-remove-if (func list)
 187   "Remove elements satisfying FUNC from LIST.
 188 Nondestructive; actually returns a copy of the list with the elements removed."
 189   (if list
 190       (if (funcall func (car list))
 191           (shadow-remove-if func (cdr list))
 192         (cons (car list) (shadow-remove-if func (cdr list))))
 193     nil))
 194
 195 (defun shadow-join (strings sep)
 196   "Concatenate elements of the list of STRINGS with SEP between each."
 197   (cond ((null strings) "")
 198         ((null (cdr strings)) (car strings))
 199         ((concat (car strings) " " (shadow-join (cdr strings) sep)))))
 200
 201 (defun shadow-regexp-superquote (string)
 202   "Like `regexp-quote', but includes the ^ and $.
 203 This makes sure regexp matches nothing but STRING."
 204   (concat "^" (regexp-quote string) "$"))
 205
 206 (defun shadow-suffix (prefix string)
 207   "If PREFIX begins STRING, return the rest.
 208 Return value is non-nil if PREFIX and STRING are `string=' up to the length of
 209 PREFIX."
 210   (let ((lp (length prefix))
 211         (ls (length string)))
 212     (if (and (>= ls lp)
 213              (string= prefix (substring string 0 lp)))
 214         (substring string lp))))
 215
 216 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 217 ;;; Clusters and sites
 218 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 219
 220 ;;; I use the term `site' to refer to a string which may be the name of a
 221 ;;; cluster or a literal hostname.  All user-level commands should accept
 222 ;;; either.
 223
 224 (defun shadow-make-cluster (name primary regexp)
 225   "Create a shadow cluster.
 226 It is called NAME, uses the PRIMARY hostname and REGEXP matching all
 227 hosts in the cluster.  The variable `shadow-clusters' associates the
 228 names of clusters to these structures.  This function is for program
 229 use: to create clusters interactively, use `shadow-define-cluster'
 230 instead."
 231   (list name primary regexp))
 232
 233 (defmacro shadow-cluster-name (cluster)
 234   "Return the name of the CLUSTER."
 235   (list 'elt cluster 0))
 236
 237 (defmacro shadow-cluster-primary (cluster)
 238   "Return the primary hostname of a CLUSTER."
 239   (list 'elt cluster 1))
 240
 241 (defmacro shadow-cluster-regexp (cluster)
 242   "Return the regexp matching hosts in a CLUSTER."
 243   (list 'elt cluster 2))
 244
 245 (defun shadow-set-cluster (name primary regexp)
 246   "Put cluster NAME on the list of clusters.
 247 Replace old definition, if any.  PRIMARY and REGEXP are the
 248 information defining the cluster.  For interactive use, call
 249 `shadow-define-cluster' instead."
 250   (let ((rest (shadow-remove-if
 251                (function (lambda (x) (equal name (car x))))
 252                shadow-clusters)))
 253     (setq shadow-clusters
 254           (cons (shadow-make-cluster name primary regexp)
 255                 rest))))
 256
 257 (defmacro shadow-get-cluster (name)
 258   "Return cluster named NAME, or nil."
 259   (list 'assoc name 'shadow-clusters))
 260
 261 (defun shadow-site-primary (site)
 262   "If SITE is a cluster, return primary host, otherwise return SITE."
 263   (let ((c (shadow-get-cluster site)))
 264     (if c
 265         (shadow-cluster-primary c)
 266       site)))
 267
 268 ;;; SITES
 269
 270 (defun shadow-site-cluster (site)
 271   "Given a SITE \(hostname or cluster name), return cluster it is in, or nil."
 272   (or (assoc site shadow-clusters)
 273       (shadow-find
 274        (function (lambda (x)
 275                    (string-match (shadow-cluster-regexp x)
 276                                  site)))
 277        shadow-clusters)))
 278
 279 (defun shadow-read-site ()
 280   "Read a cluster name or hostname from the minibuffer."
 281   (let ((ans (completing-read "Host or cluster name [RET when done]: "
 282                               shadow-clusters)))
 283     (if (equal "" ans)
 284         nil
 285       ans)))
 286
 287 (defun shadow-site-match (site1 site2)
 288   "Non-nil if SITE1 is or includes SITE2.
 289 Each may be a host or cluster name; if they are clusters, regexp of SITE1 will
 290 be matched against the primary of SITE2."
 291   (or (string-equal site1 site2) ; quick check
 292       (let* ((cluster1 (shadow-get-cluster site1))
 293              (primary2 (shadow-site-primary site2)))
 294         (if cluster1
 295             (string-match (shadow-cluster-regexp cluster1) primary2)
 296           (string-equal site1 primary2)))))
 297
 298 (defun shadow-get-user (site)
 299   "Return the default username for a SITE."
 300   (ange-ftp-get-user (shadow-site-primary site)))
 301
 302 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 303 ;;; Filename manipulation
 304 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 305
 306 (defun shadow-parse-fullname (fullname)
 307   "Parse FULLNAME into \(site user path) list.
 308 Leave it alone if it already is one.  Return nil if the argument is
 309 not a full ange-ftp pathname."
 310   (if (listp fullname)
 311       fullname
 312     (ange-ftp-ftp-name fullname)))
 313
 314 (defun shadow-parse-name (name)
 315   "Parse any NAME into \(site user name) list.
 316 Argument can be a simple name, full ange-ftp name, or already a hup list."
 317   (or (shadow-parse-fullname name)
 318       (list shadow-system-name
 319             (user-login-name)
 320             name)))
 321
 322 (defsubst shadow-make-fullname (host user name)
 323   "Make an ange-ftp style fullname out of HOST, USER (optional), and NAME.
 324 This is probably not as general as it ought to be."
 325   (concat "/"
 326           (if user (concat user "@"))
 327           host ":"
 328           name))
 329
 330 (defun shadow-replace-name-component (fullname newname)
 331   "Return FULLNAME with the name component changed to NEWNAME."
 332   (let ((hup (shadow-parse-fullname fullname)))
 333     (shadow-make-fullname (nth 0 hup) (nth 1 hup) newname)))
 334
 335 (defun shadow-local-file (file)
 336   "If FILE is at this site, remove /user@host part.
 337 If refers to a different system or a different user on this system,
 338 return nil."
 339   (let ((hup (shadow-parse-fullname file)))
 340     (cond ((null hup) file)
 341           ((and (shadow-site-match (nth 0 hup) shadow-system-name)
 342                 (string-equal (nth 1 hup) (user-login-name)))
 343            (nth 2 hup))
 344           (t nil))))
 345
 346 (defun shadow-expand-cluster-in-file-name (file)
 347   "If hostname part of FILE is a cluster, expand it to cluster's primary hostname.
 348 Will return the name bare if it is a local file."
 349   (let ((hup (shadow-parse-name file))
 350         cluster)
 351     (cond ((null hup) file)
 352           ((shadow-local-file hup))
 353           ((shadow-make-fullname (shadow-site-primary (nth 0 hup))
 354                                  (nth 1 hup)
 355                                  (nth 2 hup))))))
 356
 357 (defun shadow-expand-file-name (file &optional default)
 358   "Expand file name and get FILE's true name."
 359   (file-truename (expand-file-name file default)))
 360
 361 (defun shadow-contract-file-name (file)
 362   "Simplify FILE.
 363 Do so by replacing (when possible) home directory with ~, and hostname
 364 with cluster name that includes it.  Filename should be absolute and
 365 true."
 366   (let* ((hup (shadow-parse-name file))
 367          (homedir (if (shadow-local-file hup)
 368                       shadow-homedir
 369                     (file-name-as-directory
 370                      (nth 2 (shadow-parse-fullname
 371                              (expand-file-name
 372                               (shadow-make-fullname
 373                                (nth 0 hup) (nth 1 hup) "~")))))))
 374          (suffix (shadow-suffix homedir (nth 2 hup)))
 375          (cluster (shadow-site-cluster (nth 0 hup))))
 376     (shadow-make-fullname
 377      (if cluster
 378          (shadow-cluster-name cluster)
 379        (nth 0 hup))
 380      (nth 1 hup)
 381      (if suffix
 382          (concat "~/" suffix)
 383        (nth 2 hup)))))
 384
 385 (defun shadow-same-site (pattern file)
 386   "True if the site of PATTERN and of FILE are on the same site.
 387 If usernames are supplied, they must also match exactly.  PATTERN and FILE may
 388 be lists of host, user, name, or ange-ftp file names.  FILE may also be just a
 389 local filename."
 390   (let ((pattern-sup (shadow-parse-fullname pattern))
 391         (file-sup    (shadow-parse-name file)))
 392     (and
 393      (shadow-site-match (nth 0 pattern-sup) (nth 0 file-sup))
 394      (or (null (nth 1 pattern-sup))
 395          (string-equal (nth 1 pattern-sup) (nth 1 file-sup))))))
 396
 397 (defun shadow-file-match (pattern file &optional regexp)
 398  "Return t if PATTERN matches FILE.
 399 If REGEXP is supplied and non-nil, the file part of the pattern is a regular
 400 expression, otherwise it must match exactly.  The sites and usernames must
 401 match---see `shadow-same-site'.  The pattern must be in full ange-ftp format,
 402 but the file can be any valid filename.  This function does not do any
 403 filename expansion or contraction, you must do that yourself first."
 404  (let* ((pattern-sup (shadow-parse-fullname pattern))
 405         (file-sup (shadow-parse-name file)))
 406    (and (shadow-same-site pattern-sup file-sup)
 407         (if regexp
 408             (string-match (nth 2 pattern-sup) (nth 2 file-sup))
 409           (string-equal (nth 2 pattern-sup) (nth 2 file-sup))))))
 410
 411 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 412 ;;; User-level Commands
 413 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 414
 415 ;;;###autoload
 416 (defun shadow-define-cluster (name)
 417   "Edit \(or create) the definition of a cluster NAME.
 418 This is a group of hosts that share directories, so that copying to or from
 419 one of them is sufficient to update the file on all of them.  Clusters are
 420 defined by a name, the network address of a primary host \(the one we copy
 421 files to), and a regular expression that matches the hostnames of all the
 422 sites in the cluster."
 423   (interactive (list (completing-read "Cluster name: " shadow-clusters () ())))
 424   (let* ((old (shadow-get-cluster name))
 425          (primary (read-string "Primary host: "
 426                                (if old (shadow-cluster-primary old)
 427                                  name)))
 428          (regexp   (let (try-regexp)
 429                      (while (not
 430                              (string-match
 431                               (setq try-regexp
 432                                     (read-string
 433                                      "Regexp matching all host names: "
 434                                      (if old (shadow-cluster-regexp old)
 435                                        (shadow-regexp-superquote primary))))
 436                               primary))
 437                        (message "Regexp doesn't include the primary host!")
 438                        (sit-for 2))
 439                      try-regexp))
 440 ;        (username (read-no-blanks-input
 441 ;                   (format "Username (default %s): "
 442 ;                           (shadow-get-user primary))
 443 ;                   (if old (or (shadow-cluster-username old) "")
 444 ;                     (user-login-name))))
 445          )
 446 ;    (if (string-equal "" username) (setq username nil))
 447     (shadow-set-cluster name primary regexp)))
 448
 449 ;;;###autoload
 450 (defun shadow-define-literal-group ()
 451   "Declare a single file to be shared between sites.
 452 It may have different filenames on each site.  When this file is edited, the
 453 new version will be copied to each of the other locations.  Sites can be
 454 specific hostnames, or names of clusters \(see `shadow-define-cluster')."
 455   (interactive)
 456   (let* ((hup (shadow-parse-fullname
 457                (shadow-contract-file-name (buffer-file-name))))
 458          (name (nth 2 hup))
 459          user site group)
 460     (while (setq site (shadow-read-site))
 461       (setq user (read-string (format "Username (default %s): "
 462                                       (shadow-get-user site)))
 463             name (read-string "Filename: " name))
 464       (setq group (cons (shadow-make-fullname site
 465                                               (if (string-equal "" user)
 466                                                   (shadow-get-user site)
 467                                                 user)
 468                                               name)
 469                         group)))
 470     (setq shadow-literal-groups (cons group shadow-literal-groups)))
 471   (shadow-write-info-file))
 472
 473 ;;;###autoload
 474 (defun shadow-define-regexp-group ()
 475   "Make each of a group of files be shared between hosts.
 476 Prompts for regular expression; files matching this are shared between a list
 477 of sites, which are also prompted for.  The filenames must be identical on all
 478 hosts \(if they aren't, use `shadow-define-literal-group' instead of this
 479 function).  Each site can be either a hostname or the name of a cluster \(see
 480 `shadow-define-cluster')."
 481   (interactive)
 482   (let ((regexp (read-string
 483                  "Filename regexp: "
 484                  (if (buffer-file-name)
 485                      (shadow-regexp-superquote
 486                       (nth 2
 487                            (shadow-parse-name
 488                             (shadow-contract-file-name
 489                              (buffer-file-name))))))))
 490         site sites usernames)
 491     (while (setq site (shadow-read-site))
 492       (setq sites (cons site sites))
 493       (setq usernames
 494             (cons (read-string (format "Username for %s: " site)
 495                                (shadow-get-user site))
 496                   usernames)))
 497     (setq shadow-regexp-groups
 498           (cons (shadow-make-group regexp sites usernames)
 499                 shadow-regexp-groups))
 500     (shadow-write-info-file)))
 501
 502 (defun shadow-shadows ()
 503   ;; Mostly for debugging.
 504   "Interactive function to display shadows of a buffer."
 505   (interactive)
 506   (let ((msg (shadow-join (mapcar (function cdr)
 507                                   (shadow-shadows-of (buffer-file-name)))
 508                           " ")))
 509     (message "%s"
 510              (if (zerop (length msg))
 511                  "No shadows."
 512                msg))))
 513
 514 (defun shadow-copy-files (&optional arg)
 515   "Copy all pending shadow files.
 516 With prefix argument, copy all pending files without query.
 517 Pending copies are stored in variable `shadow-files-to-copy', and in
 518 `shadow-todo-file' if necessary.  This function is invoked by
 519 `shadow-save-buffers-kill-emacs', so it is not usually necessary to
 520 call it manually."
 521   (interactive "P")
 522   (if (not shadow-files-to-copy)
 523       (if (interactive-p)
 524           (message "No files need to be shadowed."))
 525     (save-excursion
 526       (map-y-or-n-p (function
 527                      (lambda (pair)
 528                        (or arg shadow-noquery
 529                            (format "Copy shadow file %s? " (cdr pair)))))
 530                     (function shadow-copy-file)
 531                     shadow-files-to-copy
 532                     '("shadow" "shadows" "copy"))
 533       (shadow-write-todo-file t))))
 534
 535 (defun shadow-cancel ()
 536   "Cancel the instruction to copy some files.
 537 Prompts for which copy operations to cancel.  You will not be asked to copy
 538 them again, unless you make more changes to the files.  To cancel a shadow
 539 permanently, remove the group from `shadow-literal-groups' or
 540 `shadow-regexp-groups'."
 541   (interactive)
 542   (map-y-or-n-p (function (lambda (pair)
 543                             (format "Cancel copying %s to %s? "
 544                                     (car pair) (cdr pair))))
 545                 (function (lambda (pair)
 546                             (shadow-remove-from-todo pair)))
 547                 shadow-files-to-copy
 548                 '("shadow" "shadows" "cancel copy"))
 549   (message "There are %d shadows to be updated."
 550            (length shadow-files-to-copy))
 551   (shadow-write-todo-file))
 552
 553 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 554 ;;; Internal functions
 555 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 556
 557 (defun shadow-make-group (regexp sites usernames)
 558   "Make a description of a file group---
 559 actually a list of regexp ange-ftp file names---from REGEXP \(name of file to
 560 be shadowed), list of SITES, and corresponding list of USERNAMES for each
 561 site."
 562   (if sites
 563       (cons (shadow-make-fullname (car sites) (car usernames) regexp)
 564             (shadow-make-group regexp (cdr sites) (cdr usernames)))
 565     nil))
 566
 567 (defun shadow-copy-file (s)
 568   "Copy one shadow file."
 569   (let* ((buffer
 570           (cond ((get-file-buffer
 571                   (abbreviate-file-name (shadow-expand-file-name (car s)))))
 572                 ((not (file-readable-p (car s)))
 573                  (if (y-or-n-p
 574                       (format "Cannot find file %s--cancel copy request? "
 575                               (car s)))
 576                      (shadow-remove-from-todo s))
 577                  nil)
 578                 ((or (eq t shadow-noquery)
 579                      (y-or-n-p
 580                       (format "No buffer for %s -- update shadow anyway? "
 581                               (car s))))
 582                  (find-file-noselect (car s)))))
 583          (to (shadow-expand-cluster-in-file-name (cdr s))))
 584     (when buffer
 585       (set-buffer buffer)
 586       (save-restriction
 587         (widen)
 588         (condition-case i
 589             (progn
 590               (write-region (point-min) (point-max) to)
 591               (shadow-remove-from-todo s))
 592           (error (message "Shadow %s not updated!" (cdr s))))))))
 593
 594 (defun shadow-shadows-of (file)
 595   "Return copy operations needed to update FILE.
 596 Filename should have clusters expanded, but otherwise can have any format.
 597 Return value is a list of dotted pairs like \(from . to), where from
 598 and to are absolute file names."
 599   (or (symbol-value (intern-soft file shadow-hashtable))
 600       (let* ((absolute-file (shadow-expand-file-name
 601                              (or (shadow-local-file file) file)
 602                              shadow-homedir))
 603              (canonical-file (shadow-contract-file-name absolute-file))
 604              (shadows
 605               (mapcar (function (lambda (shadow)
 606                                   (cons absolute-file shadow)))
 607                       (append
 608                        (shadow-shadows-of-1
 609                         canonical-file shadow-literal-groups nil)
 610                        (shadow-shadows-of-1
 611                         canonical-file shadow-regexp-groups t)))))
 612         (set (intern file shadow-hashtable) shadows))))
 613
 614 (defun shadow-shadows-of-1 (file groups regexp)
 615   "Return list of FILE's shadows in GROUPS.
 616 Consider them as regular expressions if third arg REGEXP is true."
 617   (if groups
 618       (let ((nonmatching
 619              (shadow-remove-if
 620               (function (lambda (x) (shadow-file-match x file regexp)))
 621               (car groups))))
 622         (append (cond ((equal nonmatching (car groups)) nil)
 623                       (regexp
 624                        (let ((realname (nth 2 (shadow-parse-fullname file))))
 625                          (mapcar
 626                           (function
 627                            (lambda (x)
 628                              (shadow-replace-name-component x realname)))
 629                           nonmatching)))
 630                       (t nonmatching))
 631                 (shadow-shadows-of-1 file (cdr groups) regexp)))))
 632
 633 (defun shadow-add-to-todo ()
 634   "If current buffer has shadows, add them to the list needing to be copied."
 635   (let ((shadows (shadow-shadows-of
 636                   (shadow-expand-file-name
 637                    (buffer-file-name (current-buffer))))))
 638     (when shadows
 639       (setq shadow-files-to-copy
 640             (shadow-union shadows shadow-files-to-copy))
 641       (when (not shadow-inhibit-message)
 642         (message "%s" (substitute-command-keys
 643                        "Use \\[shadow-copy-files] to update shadows."))
 644         (sit-for 1))
 645       (shadow-write-todo-file)))
 646   nil)     ; Return nil for write-file-hooks
 647
 648 (defun shadow-remove-from-todo (pair)
 649   "Remove PAIR from `shadow-files-to-copy'.
 650 PAIR must be `eq' to one of the elements of that list."
 651   (setq shadow-files-to-copy
 652         (shadow-remove-if (function (lambda (s) (eq s pair)))
 653                           shadow-files-to-copy)))
 654
 655 (defun shadow-read-files ()
 656   "Visit and load `shadow-info-file' and `shadow-todo-file'.
 657 Thus restores shadowfile's state from your last Emacs session.
 658 Return t unless files were locked; then return nil."
 659   (interactive)
 660   (if (and (fboundp 'file-locked-p)
 661            (or (stringp (file-locked-p shadow-info-file))
 662                (stringp (file-locked-p shadow-todo-file))))
 663       (progn
 664         (message "Shadowfile is running in another Emacs; can't have two.")
 665         (beep)
 666         (sit-for 3)
 667         nil)
 668     (save-excursion
 669       (when shadow-info-file
 670         (set-buffer (setq shadow-info-buffer
 671                           (find-file-noselect shadow-info-file)))
 672         (when (and (not (buffer-modified-p))
 673                    (file-newer-than-file-p (make-auto-save-file-name)
 674                                            shadow-info-file))
 675           (erase-buffer)
 676           (message "Data recovered from %s."
 677                    (car (insert-file-contents (make-auto-save-file-name))))
 678           (sit-for 1))
 679         (eval-buffer))
 680       (when shadow-todo-file
 681         (set-buffer (setq shadow-todo-buffer
 682                           (find-file-noselect shadow-todo-file)))
 683         (when (and (not (buffer-modified-p))
 684                    (file-newer-than-file-p (make-auto-save-file-name)
 685                                            shadow-todo-file))
 686           (erase-buffer)
 687           (message "Data recovered from %s."
 688                    (car (insert-file-contents (make-auto-save-file-name))))
 689           (sit-for 1))
 690         (eval-buffer nil))
 691       (shadow-invalidate-hashtable))
 692     t))
 693
 694 (defun shadow-write-info-file ()
 695   "Write out information to `shadow-info-file'.
 696 Also clear `shadow-hashtable', since when there are new shadows
 697 defined, the old hashtable info is invalid."
 698   (shadow-invalidate-hashtable)
 699   (if shadow-info-file
 700       (save-excursion
 701         (if (not shadow-info-buffer)
 702             (setq shadow-info-buffer (find-file-noselect shadow-info-file)))
 703         (set-buffer shadow-info-buffer)
 704         (delete-region (point-min) (point-max))
 705         (shadow-insert-var 'shadow-clusters)
 706         (shadow-insert-var 'shadow-literal-groups)
 707         (shadow-insert-var 'shadow-regexp-groups))))
 708
 709 (defun shadow-write-todo-file (&optional save)
 710   "Write out information to `shadow-todo-file'.
 711 With non-nil argument also saves the buffer."
 712   (save-excursion
 713     (if (not shadow-todo-buffer)
 714         (setq shadow-todo-buffer (find-file-noselect shadow-todo-file)))
 715     (set-buffer shadow-todo-buffer)
 716     (delete-region (point-min) (point-max))
 717     (shadow-insert-var 'shadow-files-to-copy)
 718     (if save (shadow-save-todo-file))))
 719
 720 (defun shadow-save-todo-file ()
 721   (if (and shadow-todo-buffer (buffer-modified-p shadow-todo-buffer))
 722       (save-excursion
 723         (set-buffer shadow-todo-buffer)
 724         (condition-case nil             ; have to continue even in case of
 725             (basic-save-buffer)         ; error, otherwise kill-emacs might
 726           (error                        ; not work!
 727            (message "WARNING: Can't save shadow todo file; it is locked!")
 728            (sit-for 1))))))
 729
 730 (defun shadow-invalidate-hashtable ()
 731   (setq shadow-hashtable (make-vector 37 0)))
 732
 733 (defun shadow-insert-var (variable)
 734   "Build a `setq' to restore VARIABLE.
 735 Prettily insert a `setq' command which, when later evaluated,
 736 will restore VARIABLE to its current setting.
 737 VARIABLE must be the name of a variable whose value is a list."
 738   (let ((standard-output (current-buffer)))
 739     (insert (format "(setq %s" variable))
 740     (cond ((consp (eval variable))
 741            (insert "\n  '(")
 742            (prin1 (car (eval variable)))
 743            (let ((rest (cdr (eval variable))))
 744              (while rest
 745                (insert "\n    ")
 746                (prin1 (car rest))
 747                (setq rest (cdr rest)))
 748              (insert "))\n\n")))
 749           (t (insert " ")
 750              (prin1 (eval variable))
 751              (insert ")\n\n")))))
 752
 753 (defun shadow-save-buffers-kill-emacs (&optional arg)
 754   "Offer to save each buffer and copy shadows, then kill this Emacs process.
 755 With prefix arg, silently save all file-visiting buffers, then kill.
 756
 757 Extended by shadowfile to automatically save `shadow-todo-file' and
 758 look for files that have been changed and need to be copied to other systems."
 759   ;; This function is necessary because we need to get control and save
 760   ;; the todo file /after/ saving other files, but /before/ the warning
 761   ;; message about unsaved buffers (because it can get modified by the
 762   ;; action of saving other buffers).  `kill-emacs-hook' is no good
 763   ;; because it is not called at the correct time, and also because it is
 764   ;; called when the terminal is disconnected and we cannot ask whether
 765   ;; to copy files.
 766   (interactive "P")
 767   (shadow-save-todo-file)
 768   (save-some-buffers arg t)
 769   (shadow-copy-files)
 770   (shadow-save-todo-file)
 771   (and (or (not (memq t (mapcar (function
 772                                  (lambda (buf) (and (buffer-file-name buf)
 773                                                     (buffer-modified-p buf))))
 774                                 (buffer-list))))
 775            (yes-or-no-p "Modified buffers exist; exit anyway? "))
 776        (or (not (fboundp 'process-list))
 777            ;; process-list is not defined on VMS.
 778            (let ((processes (process-list))
 779                  active)
 780              (while processes
 781                (and (memq (process-status (car processes)) '(run stop open listen))
 782                     (process-query-on-exit-flag (car processes))
 783                     (setq active t))
 784                (setq processes (cdr processes)))
 785              (or (not active)
 786                  (yes-or-no-p "Active processes exist; kill them and exit anyway? "))))
 787        (kill-emacs)))
 788
 789 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 790 ;;; Lucid Emacs compatibility
 791 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 792
 793 ;; This is on hold until someone tells me about a working version of
 794 ;; map-ynp for Lucid Emacs.
 795
 796 ;(when (string-match "Lucid" emacs-version)
 797 ;  (require 'symlink-fix)
 798 ;  (require 'ange-ftp)
 799 ;  (require 'map-ynp)
 800 ;  (if (not (fboundp 'file-truename))
 801 ;      (fset 'shadow-expand-file-name
 802 ;           (symbol-function 'symlink-expand-file-name)))
 803 ;  (if (not (fboundp 'ange-ftp-ftp-name))
 804 ;      (fset 'ange-ftp-ftp-name
 805 ;           (symbol-function 'ange-ftp-ftp-name))))
 806
 807 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 808 ;;; Hook us up
 809 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 810
 811 ;;;###autoload
 812 (defun shadow-initialize ()
 813   "Set up file shadowing."
 814   (interactive)
 815   (if (null shadow-homedir)
 816       (setq shadow-homedir
 817             (file-name-as-directory (shadow-expand-file-name "~"))))
 818   (if (null shadow-info-file)
 819       (setq shadow-info-file
 820             (shadow-expand-file-name "~/.shadows")))
 821   (if (null shadow-todo-file)
 822       (setq shadow-todo-file
 823             (shadow-expand-file-name "~/.shadow_todo")))
 824   (if (not (shadow-read-files))
 825       (progn
 826         (message "Shadowfile information files not found - aborting")
 827         (beep)
 828         (sit-for 3))
 829     (when (and (not shadow-inhibit-overload)
 830                (not (fboundp 'shadow-orig-save-buffers-kill-emacs)))
 831       (defalias 'shadow-orig-save-buffers-kill-emacs
 832         (symbol-function 'save-buffers-kill-emacs))
 833       (defalias 'save-buffers-kill-emacs 'shadow-save-buffers-kill-emacs))
 834     (add-hook 'write-file-hooks 'shadow-add-to-todo)
 835     (define-key ctl-x-4-map "s" 'shadow-copy-files)))
 836
 837 (defun shadowfile-unload-hook ()
 838   (if (fboundp 'shadow-orig-save-buffers-kill-emacs)
 839       (fset 'save-buffers-kill-emacs
 840             (symbol-function 'shadow-orig-save-buffers-kill-emacs)))
 841   (remove-hook 'write-file-hooks 'shadow-add-to-todo))
 842
 843 (add-hook 'shadowfile-unload-hook 'shadowfile-unload-hook)
 844
 845 (provide 'shadowfile)
 846
 847 ;;; arch-tag: e2f4cdd7-2bab-4def-9130-9e69b412b79e
 848 ;;; shadowfile.el ends here