lisp/org-id.el

   1 ;;; org-id.el --- Global identifier for Org-mode entries
   2 ;; Copyright (C) 2008 Free Software Foundation, Inc.
   3 ;;
   4 ;; Author: Carsten Dominik <carsten at orgmode dot org>
   5 ;; Keywords: outlines, hypermedia, calendar, wp
   6 ;; Homepage: http://orgmode.org
   7 ;; Version: 6.07b
   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 of the License, or
  14 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  23 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  24 ;;
  25 ;;; Commentary:
  26
  27 ;; This file implements globally unique identifiers for Org-mode entries.
  28 ;; Identifiers are stored in the entry as an :ID: property.  Functions
  29 ;; are provided that create and retrieve such identifiers, and that find
  30 ;; entries based on the identifier.
  31
  32 ;; Identifiers consist of a prefix (default "Org" given by the variable
  33 ;; `org-id-prefix') and a unique part that can be created by a number
  34 ;; of different methods, see the variable `org-id-method'.
  35 ;; Org has a builtin method that uses a compact encoding of the creation
  36 ;; time of the ID, with microsecond accuracy.  This virtually
  37 ;; guarantees globally unique identifiers, even if several people are
  38 ;; creating ID's at the same time in files that will eventually be used
  39 ;; together.  As an exernal method `uuidgen' is supported, if installed
  40 ;; on the system.
  41 ;;
  42 ;; This file defines the following API:
  43 ;;
  44 ;; org-id-get-create
  45 ;;        Create an ID for the entry at point if it does not yet have one.
  46 ;;        Returns the ID (old or new).  This function can be used
  47 ;;        interactively, with prefix argument the creation of a new ID is
  48 ;;        forced, even if there was an old one.
  49 ;;
  50 ;; org-id-get
  51 ;;        Get the ID property of an entry.  Using appropriate arguments
  52 ;;        to the function, it can also create the ID for this entry.
  53 ;;
  54 ;; org-id-goto
  55 ;;        Command to go to a specific ID, this command can be used
  56 ;;        interactively.
  57 ;;
  58 ;; org-id-get-with-outline-path-completion
  59 ;;        Retrieve the ID of an entry, using outline path completion.
  60 ;;        This function can work for multiple files.
  61 ;;
  62 ;; org-id-get-with-outline-drilling
  63 ;;        Retrieve the ID of an entry, using outline path completion.
  64 ;;        This function only works for the current file.
  65 ;;
  66 ;; org-id-find
  67 ;;        Find the location of an entry with specific id.
  68 ;;
  69
  70 (require 'org)
  71
  72 (declare-function message-make-fqdn "message" ())
  73
  74 ;;; Customization
  75
  76 (defgroup org-id nil
  77   "Options concerning global entry identifiers in Org-mode."
  78   :tag "Org ID"
  79   :group 'org)
  80
  81 (defcustom org-id-method 'org
  82   "The method that should be used to create new ID's.
  83
  84 An ID will consist of the prefix specified in `org-id-prefix', and a unique
  85 part created by the method this variable specifies.
  86
  87 Allowed values are:
  88
  89 org        Org's own internal method, using an encoding of the current time,
  90            and the current domain of the computer.  This method will
  91            honor the variable `org-id-include-domain'.
  92
  93 uuidgen    Call the external command uuidgen."
  94   :group 'org-id
  95   :type '(choice
  96           (const :tag "Org's internal method" org)
  97           (const :tag "external: uuidgen" uuidgen)))
  98
  99 (defcustom org-id-prefix "Org"
 100   "The prefix for IDs.
 101
 102 This may be a string, or it can be nil to indicate that no prefix is required.
 103 When a string, the string should have no space characters as IDs are expected
 104 to have no space characters in them."
 105   :group 'org-id
 106   :type '(choice
 107           (const :tag "No prefix")
 108           (string :tag "Prefix")))
 109
 110 (defcustom org-id-include-domain t
 111   "Non-nil means, add the domain name to new IDs.
 112 This ensures global uniqueness of ID's, and is also suggested by
 113 RFC 2445 in combination with RFC 822.  This is only relevant if
 114 `org-id-method' is `org'.  When uuidgen is used, the domain will never
 115 be added."
 116   :group 'org-id
 117   :type 'boolean)
 118
 119 (defcustom org-id-locations-file "~/.org-id-locations"
 120   "The file for remembering the last ID number generated."
 121   :group 'org-id
 122   :type 'file)
 123
 124 (defvar org-id-locations nil
 125   "List of files with ID's in those files.")
 126
 127 (defcustom org-id-extra-files 'org-agenda-text-search-extra-files
 128   "Files to be searched for ID's, besides the agenda files."
 129   :group 'org-id
 130   :type
 131   '(choice
 132     (symbol :tag "Variable")
 133     (repeat :tag "List of files"
 134             (file))))
 135
 136 ;;; The API functions
 137
 138 ;;;###autoload
 139 (defun org-id-get-create (&optional force)
 140   "Create an ID for the current entry and return it.
 141 If the entry already has an ID, just return it.
 142 With optional argument FORCE, force the creation of a new ID."
 143   (interactive "P")
 144   (when force
 145     (org-entry-put (point) "ID" nil))
 146   (org-id-get (point) 'create))
 147
 148 ;;;###autoload
 149 (defun org-id-copy ()
 150   "Copy the ID of the entry at point to the kill ring.
 151 Create an ID if necessary."
 152   (interactive)
 153   (kill-new (org-id-get nil 'create)))
 154
 155 ;;;###autoload
 156 (defun org-id-get (&optional pom create prefix)
 157   "Get the ID property of the entry at point-or-marker POM.
 158 If POM is nil, refer to the entry at point.
 159 If the entry does not have an ID, the function returns nil.
 160 However, when CREATE is non nil, create an ID if none is present already.
 161 PREFIX will be passed through to `org-id-new'.
 162 In any case, the ID of the entry is returned."
 163   (let ((id (org-entry-get pom "ID")))
 164     (cond
 165      ((and id (stringp id) (string-match "\\S-" id))
 166       id)
 167      (create
 168       (setq id (org-id-new prefix))
 169       (org-entry-put pom "ID" id)
 170       (org-id-add-location id (buffer-file-name (buffer-base-buffer)))
 171       id)
 172      (t nil))))
 173
 174 ;;;###autoload
 175 (defun org-id-get-with-outline-path-completion (&optional targets)
 176   "Use outline-path-completion to retrieve the ID of an entry.
 177 TARGETS may be a setting for `org-refile-targets' to define the eligible
 178 headlines.  When omitted, all headlines in all agenda files are
 179 eligible.
 180 It returns the ID of the entry.  If necessary, the ID is created."
 181   (let* ((org-refile-targets (or targets '((nil . (:maxlevel . 10)))))
 182          (org-refile-use-outline-path
 183           (if (caar org-refile-targets) 'file t))
 184          (spos (org-refile-get-location "Entry: "))
 185          (pom (and spos (move-marker (make-marker) (nth 3 spos)
 186                                      (get-file-buffer (nth 1 spos))))))
 187     (prog1 (org-id-get pom 'create)
 188       (move-marker pom nil))))
 189
 190 ;;;###autoload
 191 (defun org-id-get-with-outline-drilling (&optional targets)
 192   "Use an outline-cycling interface to retrieve the ID of an entry.
 193 This only finds entries in the current buffer, using `org-get-location'.
 194 It returns the ID of the entry.  If necessary, the ID is created."
 195   (let* ((spos (org-get-location (current-buffer) org-goto-help))
 196          (pom (and spos (move-marker (make-marker) (car spos)))))
 197     (prog1 (org-id-get pom 'create)
 198       (move-marker pom nil))))
 199
 200 ;;;###autoload
 201 (defun org-id-goto (id)
 202   "Switch to the buffer containing the entry with id ID.
 203 Move the cursor to that entry in that buffer."
 204   (interactive)
 205   (let ((m (org-id-find id 'marker)))
 206     (unless m
 207       (error "Cannot find entry with ID \"%s\"" id))
 208     (switch-to-buffer (marker-buffer m))
 209     (goto-char m)
 210     (move-marker m nil)
 211     (org-show-context)))
 212
 213 ;;;###autoload
 214 (defun org-id-find (id &optional markerp)
 215   "Return the location of the entry with the id ID.
 216 The return value is a cons cell (file-name . position), or nil
 217 if there is no entry with that ID.
 218 With optional argument MARKERP, return the position as a new marker."
 219   (let ((file (org-id-find-id-file id))
 220         org-agenda-new-buffers where)
 221     (when file
 222       (setq where (org-id-find-id-in-file id file markerp)))
 223     (unless where
 224       (org-id-update-id-locations)
 225       (setq file (org-id-find-id-file id))
 226       (when file
 227         (setq where (org-id-find-id-in-file id file markerp))))
 228     where))
 229
 230 ;;; Internal functions
 231
 232 ;; Creating new IDs
 233
 234 (defun org-id-new (&optional prefix)
 235   "Create a new globally unique ID.
 236
 237 An ID consists of two parts separated by a colon:
 238 - a prefix
 239 - a unique part that will be created according to `org-id-method'.
 240
 241 PREFIX can specify the prefix, the default is given by the variable
 242 `org-id-prefix'.  However, if PREFIX is the symbol `none', don't use any
 243 prefix even if `org-id-prefix' specifies one.
 244
 245 So a typical ID could look like \"Org:4nd91V40HI\"."
 246   (let* ((prefix (if (eq prefix 'none)
 247                      ""
 248                    (concat (or prefix org-id-prefix) ":")))
 249          unique)
 250     (if (equal prefix ":") (setq prefix ""))
 251     (cond
 252      ((eq org-id-method 'uuidgen)
 253       (setq unique (substring (shell-command-to-string "uuidgen") 1 -1)))
 254      ((eq org-id-method 'org)
 255       (let* ((etime (org-id-time-to-b62))
 256              (postfix (if org-id-include-domain
 257                           (progn
 258                             (require 'message)
 259                             (concat "@" (message-make-fqdn))))))
 260         (setq unique (concat etime postfix))))
 261      (t (error "Invalid `org-id-method'")))
 262     (concat prefix unique)))
 263
 264 (defun org-id-int-to-b62-one-digit (i)
 265   "Turn an integer between 0 and 61 into a single character 0..9, A..Z, a..z."
 266   (cond
 267    ((< i 10) (+ ?0 i))
 268    ((< i 36) (+ ?A i -10))
 269    ((< i 62) (+ ?a i -36))
 270    (t (error "Larger that 61"))))
 271
 272 (defun org-id-b62-to-int-one-digit (i)
 273   "Turn a character 0..9, A..Z, a..z into a number 0..61.
 274 The input I may be a character, or a single-letter string."
 275   (and (stringp i) (setq i (string-to-char i)))
 276   (cond
 277    ((and (>= i ?0) (<= i ?9)) (- i ?0))
 278    ((and (>= i ?A) (<= i ?Z)) (+ (- i ?A) 10))
 279    ((and (>= i ?a) (<= i ?z)) (+ (- i ?a) 36))
 280    (t (error "Invalid b62 letter"))))
 281
 282 (defun org-id-int-to-b62 (i &optional length)
 283   "Convert an integer to a base-62 number represented as a string."
 284   (let ((s ""))
 285     (while (> i 0)
 286       (setq s (concat (char-to-string
 287                        (org-id-int-to-b62-one-digit (mod i 62))) s)
 288             i (/ i 62)))
 289     (setq length (max 1 (or length 1)))
 290     (if (< (length s) length)
 291         (setq s (concat (make-string (- length (length s)) ?0) s)))
 292     s))
 293
 294 (defun org-id-b62-to-int (s)
 295   "Convert a base-62 string into the corresponding integer."
 296   (let ((r 0))
 297     (mapc (lambda (i) (setq r (+ (* r 62) (org-id-b62-to-int-one-digit i))))
 298           s)
 299     r))
 300
 301 (defun org-id-time-to-b62 (&optional time)
 302   "Encode TIME as a 10-digit string.
 303 This string holds the time to micro-second accuracy, and can be decoded
 304 using `org-id-decode'."
 305   (setq time (or time (current-time)))
 306   (concat (org-id-int-to-b62 (nth 0 time) 3)
 307           (org-id-int-to-b62 (nth 1 time) 3)
 308           (org-id-int-to-b62 (or (nth 2 time) 0) 4)))
 309
 310 (defun org-id-decode (id)
 311   "Split ID into the prefix and the time value that was used to create it.
 312 The return value is (prefix . time) where PREFIX is nil or a string,
 313 and time is the usual three-integer representation of time."
 314   (let (prefix time parts)
 315     (setq parts (org-split-string id ":"))
 316     (if (= 2 (length parts))
 317         (setq prefix (car parts) time (nth 1 parts))
 318       (setq prefix nil time (nth 0 parts)))
 319     (setq time (list (org-id-b62-to-int (substring time 0 3))
 320                      (org-id-b62-to-int (substring time 3 6))
 321                      (org-id-b62-to-int (substring time 6 10))))
 322     (cons prefix time)))
 323
 324 ;; Storing ID locations (files)
 325
 326 (defun org-id-update-id-locations ()
 327   "Scan relevant files for ID's.
 328 Store the relation between files and corresponding ID's."
 329   (interactive)
 330   (let ((files (append (org-agenda-files)
 331                        (if (symbolp org-id-extra-files)
 332                            (symbol-value org-id-extra-files)
 333                          org-id-extra-files)))
 334         org-agenda-new-buffers
 335         file ids reg found id)
 336     (while (setq file (pop files))
 337       (setq ids nil)
 338       (with-current-buffer (org-get-agenda-file-buffer file)
 339         (save-excursion
 340           (save-restriction
 341             (widen)
 342             (goto-char (point-min))
 343             (while (re-search-forward "^[ \t]*:ID:[ \t]+\\(\\S-+\\)[ \t]*$"
 344                                       nil t)
 345               (setq id (org-match-string-no-properties 1))
 346               (if (member id found)
 347                   (error "Duplicate ID \"%s\"" id))
 348               (push id found)
 349               (push id ids))
 350             (push (cons file ids) reg)))))
 351     (org-release-buffers org-agenda-new-buffers)
 352     (setq org-agenda-new-buffers nil)
 353     (setq org-id-locations reg)
 354     (org-id-locations-save)))
 355
 356 (defun org-id-locations-save ()
 357   "Save `org-id-locations' in `org-id-locations-file'."
 358   (with-temp-file org-id-locations-file
 359     (print org-id-locations (current-buffer))))
 360
 361 (defun org-id-locations-load ()
 362   "Read the data from `org-id-locations-file'."
 363   (setq org-id-locations nil)
 364   (with-temp-buffer
 365     (condition-case nil
 366         (progn
 367           (insert-file-contents-literally org-id-locations-file)
 368           (goto-char (point-min))
 369           (setq org-id-locations (read (current-buffer))))
 370       (error
 371        (message "Could not read org-id-values from %s. Setting it to nil."
 372                 org-id-locations-file)))))
 373
 374 (defun org-id-add-location (id file)
 375   "Add the ID with location FILE to the database of ID loations."
 376   (unless org-id-locations (org-id-locations-load))
 377   (catch 'exit
 378     (let ((locs org-id-locations) list)
 379       (while (setq list (pop locs))
 380         (when (equal (file-truename file) (file-truename (car list)))
 381           (setcdr list (cons id (cdr list)))
 382           (throw 'exit t))))
 383     (push (list file id) org-id-locations))
 384   (org-id-locations-save))
 385
 386 ;; Finding entries with specified id
 387
 388 (defun org-id-find-id-file (id)
 389   "Query the id database for the file in which this ID is located."
 390   (unless org-id-locations (org-id-locations-load))
 391   (catch 'found
 392     (mapc (lambda (x) (if (member id (cdr x))
 393                           (throw 'found (car x))))
 394           org-id-locations)
 395     nil))
 396
 397 (defun org-id-find-id-in-file (id file &optional markerp)
 398   "Return the position of the entry ID in FILE.
 399 If that files does not exist, or if it does not contain this ID,
 400 return nil.
 401 The position is returned as a cons cell (file-name . position).  With
 402 optional argument MARKERP, return the position as a new marker."
 403   (let (org-agenda-new-buffers m buf pos)
 404     (cond
 405      ((not file) nil)
 406      ((not (file-exists-p file)) nil)
 407      (t (with-current-buffer (setq buf (org-get-agenda-file-buffer file))
 408           (setq pos (org-find-entry-with-id id))
 409           (when pos
 410             (if markerp
 411                 (move-marker (make-marker) pos buf)
 412               (cons file pos))))))))
 413
 414 (provide 'org-id)
 415
 416 ;;; org-id.el ends here
 417
 418 ;; arch-tag: e5abaca4-e16f-4b25-832a-540cfb63a712