lisp/org-id.el

   1 ;;; org-id.el --- Global identifiers for Org entries -*- lexical-binding: t; -*-
   2 ;;
   3 ;; Copyright (C) 2008-2017 Free Software Foundation, Inc.
   4 ;;
   5 ;; Author: Carsten Dominik <carsten at orgmode dot org>
   6 ;; Keywords: outlines, hypermedia, calendar, wp
   7 ;; Homepage: http://orgmode.org
   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 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 IDs at the same time in files that will eventually be used
  39 ;; together.
  40 ;;
  41 ;; By default Org uses UUIDs as global unique identifiers.
  42 ;;
  43 ;; This file defines the following API:
  44 ;;
  45 ;; org-id-get-create
  46 ;;        Create an ID for the entry at point if it does not yet have one.
  47 ;;        Returns the ID (old or new).  This function can be used
  48 ;;        interactively, with prefix argument the creation of a new ID is
  49 ;;        forced, even if there was an old one.
  50 ;;
  51 ;; org-id-get
  52 ;;        Get the ID property of an entry.  Using appropriate arguments
  53 ;;        to the function, it can also create the ID for this entry.
  54 ;;
  55 ;; org-id-goto
  56 ;;        Command to go to a specific ID, this command can be used
  57 ;;        interactively.
  58 ;;
  59 ;; org-id-get-with-outline-path-completion
  60 ;;        Retrieve the ID of an entry, using outline path completion.
  61 ;;        This function can work for multiple files.
  62 ;;
  63 ;; org-id-get-with-outline-drilling
  64 ;;        Retrieve the ID of an entry, using outline path completion.
  65 ;;        This function only works for the current file.
  66 ;;
  67 ;; org-id-find
  68 ;;        Find the location of an entry with specific id.
  69 ;;
  70
  71 ;;; Code:
  72
  73 (require 'org)
  74
  75 (declare-function message-make-fqdn "message" ())
  76
  77 ;;; Customization
  78
  79 (defgroup org-id nil
  80   "Options concerning global entry identifiers in Org mode."
  81   :tag "Org ID"
  82   :group 'org)
  83
  84 (defcustom org-id-link-to-org-use-id nil
  85   "Non-nil means storing a link to an Org file will use entry IDs.
  86 \\<org-mode-map>\
  87
  88 The variable can have the following values:
  89
  90 t     Create an ID if needed to make a link to the current entry.
  91
  92 create-if-interactive
  93       If `org-store-link' is called directly (interactively, as a user
  94       command), do create an ID to support the link.  But when doing the
  95       job for capture, only use the ID if it already exists.  The
  96       purpose of this setting is to avoid proliferation of unwanted
  97       IDs, just because you happen to be in an Org file when you
  98       call `org-capture' that automatically and preemptively creates a
  99       link.  If you do want to get an ID link in a capture template to
 100       an entry not having an ID, create it first by explicitly creating
 101       a link to it, using `\\[org-store-link]' first.
 102
 103 create-if-interactive-and-no-custom-id
 104       Like create-if-interactive, but do not create an ID if there is
 105       a CUSTOM_ID property defined in the entry.
 106
 107 use-existing
 108       Use existing ID, do not create one.
 109
 110 nil   Never use an ID to make a link, instead link using a text search for
 111       the headline text."
 112   :group 'org-link-store
 113   :group 'org-id
 114   :version "24.3"
 115   :type '(choice
 116           (const :tag "Create ID to make link" t)
 117           (const :tag "Create if storing link interactively"
 118                  create-if-interactive)
 119           (const :tag "Create if storing link interactively and no CUSTOM_ID is present"
 120                  create-if-interactive-and-no-custom-id)
 121           (const :tag "Only use existing" use-existing)
 122           (const :tag "Do not use ID to create link" nil)))
 123
 124 (defcustom org-id-uuid-program "uuidgen"
 125   "The uuidgen program."
 126   :group 'org-id
 127   :type 'string)
 128
 129 (defcustom org-id-method 'uuid
 130   "The method that should be used to create new IDs.
 131
 132 An ID will consist of the optional prefix specified in `org-id-prefix',
 133 and a unique part created by the method this variable specifies.
 134
 135 Allowed values are:
 136
 137 org        Org's own internal method, using an encoding of the current time to
 138            microsecond accuracy, and optionally the current domain of the
 139            computer.  See the variable `org-id-include-domain'.
 140
 141 uuid       Create random (version 4) UUIDs.  If the program defined in
 142            `org-id-uuid-program' is available it is used to create the ID.
 143            Otherwise an internal functions is used."
 144   :group 'org-id
 145   :type '(choice
 146           (const :tag "Org's internal method" org)
 147           (const :tag "external: uuidgen" uuid)))
 148
 149 (defcustom org-id-prefix nil
 150   "The prefix for IDs.
 151
 152 This may be a string, or it can be nil to indicate that no prefix is required.
 153 When a string, the string should have no space characters as IDs are expected
 154 to have no space characters in them."
 155   :group 'org-id
 156   :type '(choice
 157           (const :tag "No prefix")
 158           (string :tag "Prefix")))
 159
 160 (defcustom org-id-include-domain nil
 161   "Non-nil means add the domain name to new IDs.
 162 This ensures global uniqueness of IDs, and is also suggested by
 163 RFC 2445 in combination with RFC 822.  This is only relevant if
 164 `org-id-method' is `org'.  When uuidgen is used, the domain will never
 165 be added.
 166 The default is to not use this because we have no really good way to get
 167 the true domain, and Org entries will normally not be shared with enough
 168 people to make this necessary."
 169   :group 'org-id
 170   :type 'boolean)
 171
 172 (defcustom org-id-track-globally t
 173   "Non-nil means track IDs through files, so that links work globally.
 174 This work by maintaining a hash table for IDs and writing this table
 175 to disk when exiting Emacs.  Because of this, it works best if you use
 176 a single Emacs process, not many.
 177
 178 When nil, IDs are not tracked.  Links to IDs will still work within
 179 a buffer, but not if the entry is located in another file.
 180 IDs can still be used if the entry with the id is in the same file as
 181 the link."
 182   :group 'org-id
 183   :type 'boolean)
 184
 185 (defcustom org-id-locations-file (convert-standard-filename
 186                                   (concat user-emacs-directory ".org-id-locations"))
 187   "The file for remembering in which file an ID was defined.
 188 This variable is only relevant when `org-id-track-globally' is set."
 189   :group 'org-id
 190   :type 'file)
 191
 192 (defvar org-id-locations nil
 193   "List of files with IDs in those files.")
 194
 195 (defvar org-id-files nil
 196   "List of files that contain IDs.")
 197
 198 (defcustom org-id-extra-files 'org-agenda-text-search-extra-files
 199   "Files to be searched for IDs, besides the agenda files.
 200 When Org reparses files to remake the list of files and IDs it is tracking,
 201 it will normally scan the agenda files, the archives related to agenda files,
 202 any files that are listed as ID containing in the current register, and
 203 any Org file currently visited by Emacs.
 204 You can list additional files here.
 205 This variable is only relevant when `org-id-track-globally' is set."
 206   :group 'org-id
 207   :type
 208   '(choice
 209     (symbol :tag "Variable")
 210     (repeat :tag "List of files"
 211             (file))))
 212
 213 (defcustom org-id-search-archives t
 214   "Non-nil means search also the archive files of agenda files for entries.
 215 This is a possibility to reduce overhead, but it means that entries moved
 216 to the archives can no longer be found by ID.
 217 This variable is only relevant when `org-id-track-globally' is set."
 218   :group 'org-id
 219   :type 'boolean)
 220
 221 ;;; The API functions
 222
 223 ;;;###autoload
 224 (defun org-id-get-create (&optional force)
 225   "Create an ID for the current entry and return it.
 226 If the entry already has an ID, just return it.
 227 With optional argument FORCE, force the creation of a new ID."
 228   (interactive "P")
 229   (when force
 230     (org-entry-put (point) "ID" nil))
 231   (org-id-get (point) 'create))
 232
 233 ;;;###autoload
 234 (defun org-id-copy ()
 235   "Copy the ID of the entry at point to the kill ring.
 236 Create an ID if necessary."
 237   (interactive)
 238   (org-kill-new (org-id-get nil 'create)))
 239
 240 ;;;###autoload
 241 (defun org-id-get (&optional pom create prefix)
 242   "Get the ID property of the entry at point-or-marker POM.
 243 If POM is nil, refer to the entry at point.
 244 If the entry does not have an ID, the function returns nil.
 245 However, when CREATE is non nil, create an ID if none is present already.
 246 PREFIX will be passed through to `org-id-new'.
 247 In any case, the ID of the entry is returned."
 248   (org-with-point-at pom
 249     (let ((id (org-entry-get nil "ID")))
 250       (cond
 251        ((and id (stringp id) (string-match "\\S-" id))
 252         id)
 253        (create
 254         (setq id (org-id-new prefix))
 255         (org-entry-put pom "ID" id)
 256         (org-id-add-location id (buffer-file-name (buffer-base-buffer)))
 257         id)))))
 258
 259 ;;;###autoload
 260 (defun org-id-get-with-outline-path-completion (&optional targets)
 261   "Use `outline-path-completion' to retrieve the ID of an entry.
 262 TARGETS may be a setting for `org-refile-targets' to define
 263 eligible headlines.  When omitted, all headlines in the current
 264 file are eligible.  This function returns the ID of the entry.
 265 If necessary, the ID is created."
 266   (let* ((org-refile-targets (or targets '((nil . (:maxlevel . 10)))))
 267          (org-refile-use-outline-path
 268           (if (caar org-refile-targets) 'file t))
 269          (org-refile-target-verify-function nil)
 270          (spos (org-refile-get-location "Entry"))
 271          (pom (and spos (move-marker (make-marker) (nth 3 spos)
 272                                      (get-file-buffer (nth 1 spos))))))
 273     (prog1 (org-id-get pom 'create)
 274       (move-marker pom nil))))
 275
 276 ;;;###autoload
 277 (defun org-id-get-with-outline-drilling ()
 278   "Use an outline-cycling interface to retrieve the ID of an entry.
 279 This only finds entries in the current buffer, using `org-get-location'.
 280 It returns the ID of the entry.  If necessary, the ID is created."
 281   (let* ((spos (org-get-location (current-buffer) org-goto-help))
 282          (pom (and spos (move-marker (make-marker) (car spos)))))
 283     (prog1 (org-id-get pom 'create)
 284       (move-marker pom nil))))
 285
 286 ;;;###autoload
 287 (defun org-id-goto (id)
 288   "Switch to the buffer containing the entry with id ID.
 289 Move the cursor to that entry in that buffer."
 290   (interactive "sID: ")
 291   (let ((m (org-id-find id 'marker)))
 292     (unless m
 293       (error "Cannot find entry with ID \"%s\"" id))
 294     (pop-to-buffer-same-window (marker-buffer m))
 295     (goto-char m)
 296     (move-marker m nil)
 297     (org-show-context)))
 298
 299 ;;;###autoload
 300 (defun org-id-find (id &optional markerp)
 301   "Return the location of the entry with the id ID.
 302 The return value is a cons cell (file-name . position), or nil
 303 if there is no entry with that ID.
 304 With optional argument MARKERP, return the position as a new marker."
 305   (cond
 306    ((symbolp id) (setq id (symbol-name id)))
 307    ((numberp id) (setq id (number-to-string id))))
 308   (let ((file (org-id-find-id-file id))
 309         org-agenda-new-buffers where)
 310     (when file
 311       (setq where (org-id-find-id-in-file id file markerp)))
 312     (unless where
 313       (org-id-update-id-locations nil t)
 314       (setq file (org-id-find-id-file id))
 315       (when file
 316         (setq where (org-id-find-id-in-file id file markerp))))
 317     where))
 318
 319 ;;; Internal functions
 320
 321 ;; Creating new IDs
 322
 323 ;;;###autoload
 324 (defun org-id-new (&optional prefix)
 325   "Create a new globally unique ID.
 326
 327 An ID consists of two parts separated by a colon:
 328 - a prefix
 329 - a unique part that will be created according to `org-id-method'.
 330
 331 PREFIX can specify the prefix, the default is given by the variable
 332 `org-id-prefix'.  However, if PREFIX is the symbol `none', don't use any
 333 prefix even if `org-id-prefix' specifies one.
 334
 335 So a typical ID could look like \"Org:4nd91V40HI\"."
 336   (let* ((prefix (if (eq prefix 'none)
 337                      ""
 338                    (concat (or prefix org-id-prefix) ":")))
 339          unique)
 340     (if (equal prefix ":") (setq prefix ""))
 341     (cond
 342      ((memq org-id-method '(uuidgen uuid))
 343       (setq unique (org-trim (shell-command-to-string org-id-uuid-program)))
 344       (unless (org-uuidgen-p unique)
 345         (setq unique (org-id-uuid))))
 346      ((eq org-id-method 'org)
 347       (let* ((etime (org-reverse-string (org-id-time-to-b36)))
 348              (postfix (if org-id-include-domain
 349                           (progn
 350                             (require 'message)
 351                             (concat "@" (message-make-fqdn))))))
 352         (setq unique (concat etime postfix))))
 353      (t (error "Invalid `org-id-method'")))
 354     (concat prefix unique)))
 355
 356 (defun org-id-uuid ()
 357   "Return string with random (version 4) UUID."
 358   (let ((rnd (md5 (format "%s%s%s%s%s%s%s"
 359                           (random)
 360                           (current-time)
 361                           (user-uid)
 362                           (emacs-pid)
 363                           (user-full-name)
 364                           user-mail-address
 365                           (recent-keys)))))
 366     (format "%s-%s-4%s-%s%s-%s"
 367             (substring rnd 0 8)
 368             (substring rnd 8 12)
 369             (substring rnd 13 16)
 370             (format "%x"
 371                     (logior
 372                      #b10000000
 373                      (logand
 374                       #b10111111
 375                       (string-to-number
 376                        (substring rnd 16 18) 16))))
 377             (substring rnd 18 20)
 378             (substring rnd 20 32))))
 379
 380 (defun org-id-int-to-b36-one-digit (i)
 381   "Turn an integer between 0 and 61 into a single character 0..9, A..Z, a..z."
 382   (cond
 383    ((< i 10) (+ ?0 i))
 384    ((< i 36) (+ ?a i -10))
 385    (t (error "Larger that 35"))))
 386
 387 (defun org-id-b36-to-int-one-digit (i)
 388   "Turn a character 0..9, A..Z, a..z into a number 0..61.
 389 The input I may be a character, or a single-letter string."
 390   (and (stringp i) (setq i (string-to-char i)))
 391   (cond
 392    ((and (>= i ?0) (<= i ?9)) (- i ?0))
 393    ((and (>= i ?a) (<= i ?z)) (+ (- i ?a) 10))
 394    (t (error "Invalid b36 letter"))))
 395
 396 (defun org-id-int-to-b36 (i &optional length)
 397   "Convert an integer to a base-36 number represented as a string."
 398   (let ((s ""))
 399     (while (> i 0)
 400       (setq s (concat (char-to-string
 401                        (org-id-int-to-b36-one-digit (mod i 36))) s)
 402             i (/ i 36)))
 403     (setq length (max 1 (or length 1)))
 404     (if (< (length s) length)
 405         (setq s (concat (make-string (- length (length s)) ?0) s)))
 406     s))
 407
 408 (defun org-id-b36-to-int (s)
 409   "Convert a base-36 string into the corresponding integer."
 410   (let ((r 0))
 411     (mapc (lambda (i) (setq r (+ (* r 36) (org-id-b36-to-int-one-digit i))))
 412           s)
 413     r))
 414
 415 (defun org-id-time-to-b36 (&optional time)
 416   "Encode TIME as a 10-digit string.
 417 This string holds the time to micro-second accuracy, and can be decoded
 418 using `org-id-decode'."
 419   (setq time (or time (current-time)))
 420   (concat (org-id-int-to-b36 (nth 0 time) 4)
 421           (org-id-int-to-b36 (nth 1 time) 4)
 422           (org-id-int-to-b36 (or (nth 2 time) 0) 4)))
 423
 424 (defun org-id-decode (id)
 425   "Split ID into the prefix and the time value that was used to create it.
 426 The return value is (prefix . time) where PREFIX is nil or a string,
 427 and time is the usual three-integer representation of time."
 428   (let (prefix time parts)
 429     (setq parts (org-split-string id ":"))
 430     (if (= 2 (length parts))
 431         (setq prefix (car parts) time (nth 1 parts))
 432       (setq prefix nil time (nth 0 parts)))
 433     (setq time (org-reverse-string time))
 434     (setq time (list (org-id-b36-to-int (substring time 0 4))
 435                      (org-id-b36-to-int (substring time 4 8))
 436                      (org-id-b36-to-int (substring time 8 12))))
 437     (cons prefix time)))
 438
 439 ;; Storing ID locations (files)
 440
 441 ;;;###autoload
 442 (defun org-id-update-id-locations (&optional files silent)
 443   "Scan relevant files for IDs.
 444 Store the relation between files and corresponding IDs.
 445 This will scan all agenda files, all associated archives, and all
 446 files currently mentioned in `org-id-locations'.
 447 When FILES is given, scan these files instead."
 448   (interactive)
 449   (if (not org-id-track-globally)
 450       (error "Please turn on `org-id-track-globally' if you want to track IDs")
 451     (let* ((org-id-search-archives
 452             (or org-id-search-archives
 453                 (and (symbolp org-id-extra-files)
 454                      (symbol-value org-id-extra-files)
 455                      (member 'agenda-archives org-id-extra-files))))
 456            (files
 457             (or files
 458                 (append
 459                  ;; Agenda files and all associated archives
 460                  (org-agenda-files t org-id-search-archives)
 461                  ;; Explicit extra files
 462                  (if (symbolp org-id-extra-files)
 463                      (symbol-value org-id-extra-files)
 464                    org-id-extra-files)
 465                  ;; Files associated with live Org buffers
 466                  (delq nil
 467                        (mapcar (lambda (b)
 468                                  (with-current-buffer b
 469                                    (and (derived-mode-p 'org-mode) (buffer-file-name))))
 470                                (buffer-list)))
 471                  ;; All files known to have IDs
 472                  org-id-files)))
 473            org-agenda-new-buffers
 474            file nfiles tfile ids reg found id seen (ndup 0))
 475       (when (member 'agenda-archives files)
 476         (setq files (delq 'agenda-archives (copy-sequence files))))
 477       (setq nfiles (length files))
 478       (while (setq file (pop files))
 479         (unless silent
 480           (message "Finding ID locations (%d/%d files): %s"
 481                    (- nfiles (length files)) nfiles file))
 482         (setq tfile (file-truename file))
 483         (when (and (file-exists-p file) (not (member tfile seen)))
 484           (push tfile seen)
 485           (setq ids nil)
 486           (with-current-buffer (org-get-agenda-file-buffer file)
 487             (save-excursion
 488               (save-restriction
 489                 (widen)
 490                 (goto-char (point-min))
 491                 (while (re-search-forward "^[ \t]*:ID:[ \t]+\\(\\S-+\\)[ \t]*$"
 492                                           nil t)
 493                   (setq id (match-string-no-properties 1))
 494                   (if (member id found)
 495                       (progn
 496                         (message "Duplicate ID \"%s\", also in file %s"
 497                                  id (or (car (delq
 498                                               nil
 499                                               (mapcar
 500                                                (lambda (x)
 501                                                  (if (member id (cdr x))
 502                                                      (car x)))
 503                                                reg)))
 504                                         (buffer-file-name)))
 505                         (when (= ndup 0)
 506                           (ding)
 507                           (sit-for 2))
 508                         (setq ndup (1+ ndup)))
 509                     (push id found)
 510                     (push id ids)))
 511                 (push (cons (abbreviate-file-name file) ids) reg))))))
 512       (org-release-buffers org-agenda-new-buffers)
 513       (setq org-agenda-new-buffers nil)
 514       (setq org-id-locations reg)
 515       (setq org-id-files (mapcar 'car org-id-locations))
 516       (org-id-locations-save) ;; this function can also handle the alist form
 517       ;; now convert to a hash
 518       (setq org-id-locations (org-id-alist-to-hash org-id-locations))
 519       (if (> ndup 0)
 520           (message "WARNING: %d duplicate IDs found, check *Messages* buffer" ndup)
 521         (message "%d unique files scanned for IDs" (length org-id-files)))
 522       org-id-locations)))
 523
 524 (defun org-id-locations-save ()
 525   "Save `org-id-locations' in `org-id-locations-file'."
 526   (when (and org-id-track-globally org-id-locations)
 527     (let ((out (if (hash-table-p org-id-locations)
 528                    (org-id-hash-to-alist org-id-locations)
 529                  org-id-locations)))
 530       (with-temp-file org-id-locations-file
 531         (let ((print-level nil)
 532               (print-length nil))
 533           (print out (current-buffer)))))))
 534
 535 (defun org-id-locations-load ()
 536   "Read the data from `org-id-locations-file'."
 537   (setq org-id-locations nil)
 538   (when org-id-track-globally
 539     (with-temp-buffer
 540       (condition-case nil
 541           (progn
 542             (insert-file-contents-literally org-id-locations-file)
 543             (goto-char (point-min))
 544             (setq org-id-locations (read (current-buffer))))
 545         (error
 546          (message "Could not read org-id-values from %s.  Setting it to nil."
 547                   org-id-locations-file))))
 548     (setq org-id-files (mapcar 'car org-id-locations))
 549     (setq org-id-locations (org-id-alist-to-hash org-id-locations))))
 550
 551 (defun org-id-add-location (id file)
 552   "Add the ID with location FILE to the database of ID locations."
 553   ;; Only if global tracking is on, and when the buffer has a file
 554   (when (and org-id-track-globally id file)
 555     (unless org-id-locations (org-id-locations-load))
 556     (puthash id (abbreviate-file-name file) org-id-locations)
 557     (add-to-list 'org-id-files (abbreviate-file-name file))))
 558
 559 (unless noninteractive
 560   (add-hook 'kill-emacs-hook 'org-id-locations-save))
 561
 562 (defun org-id-hash-to-alist (hash)
 563   "Turn an org-id hash into an alist, so that it can be written to a file."
 564   (let (res x)
 565     (maphash
 566      (lambda (k v)
 567        (if (setq x (member v res))
 568            (setcdr x (cons k (cdr x)))
 569          (push (list v k) res)))
 570      hash)
 571     res))
 572
 573 (defun org-id-alist-to-hash (list)
 574   "Turn an org-id location list into a hash table."
 575   (let ((res (make-hash-table
 576               :test 'equal
 577               :size (apply '+ (mapcar 'length list))))
 578         f)
 579     (mapc
 580      (lambda (x)
 581        (setq f (car x))
 582        (mapc (lambda (i) (puthash i f res)) (cdr x)))
 583      list)
 584     res))
 585
 586 (defun org-id-paste-tracker (txt &optional buffer-or-file)
 587   "Update any IDs in TXT and assign BUFFER-OR-FILE to them."
 588   (when org-id-track-globally
 589     (save-match-data
 590       (setq buffer-or-file (or buffer-or-file (current-buffer)))
 591       (when (bufferp buffer-or-file)
 592         (setq buffer-or-file (or (buffer-base-buffer buffer-or-file)
 593                                  buffer-or-file))
 594         (setq buffer-or-file (buffer-file-name buffer-or-file)))
 595       (when buffer-or-file
 596         (let ((fname (abbreviate-file-name buffer-or-file))
 597               (s 0))
 598           (while (string-match "^[ \t]*:ID:[ \t]+\\([^ \t\n\r]+\\)" txt s)
 599             (setq s (match-end 0))
 600             (org-id-add-location (match-string 1 txt) fname)))))))
 601
 602 ;; Finding entries with specified id
 603
 604 ;;;###autoload
 605 (defun org-id-find-id-file (id)
 606   "Query the id database for the file in which this ID is located."
 607   (unless org-id-locations (org-id-locations-load))
 608   (or (and org-id-locations
 609            (hash-table-p org-id-locations)
 610            (gethash id org-id-locations))
 611       ;; ball back on current buffer
 612       (buffer-file-name (or (buffer-base-buffer (current-buffer))
 613                             (current-buffer)))))
 614
 615 (defun org-id-find-id-in-file (id file &optional markerp)
 616   "Return the position of the entry ID in FILE.
 617 If that files does not exist, or if it does not contain this ID,
 618 return nil.
 619 The position is returned as a cons cell (file-name . position).  With
 620 optional argument MARKERP, return the position as a new marker."
 621   (let (org-agenda-new-buffers buf pos)
 622     (cond
 623      ((not file) nil)
 624      ((not (file-exists-p file)) nil)
 625      (t (with-current-buffer (setq buf (org-get-agenda-file-buffer file))
 626           (setq pos (org-find-entry-with-id id))
 627           (when pos
 628             (if markerp
 629                 (move-marker (make-marker) pos buf)
 630               (cons file pos))))))))
 631
 632 ;; id link type
 633
 634 ;; Calling the following function is hard-coded into `org-store-link',
 635 ;; so we do have to add it to `org-store-link-functions'.
 636
 637 ;;;###autoload
 638 (defun org-id-store-link ()
 639   "Store a link to the current entry, using its ID."
 640   (interactive)
 641   (when (and (buffer-file-name (buffer-base-buffer)) (derived-mode-p 'org-mode))
 642     (let* ((link (concat "id:" (org-id-get-create)))
 643            (case-fold-search nil)
 644            (desc (save-excursion
 645                    (org-back-to-heading t)
 646                    (or (and (looking-at org-complex-heading-regexp)
 647                             (if (match-end 4)
 648                                 (match-string 4)
 649                               (match-string 0)))
 650                        link))))
 651       (org-store-link-props :link link :description desc :type "id")
 652       link)))
 653
 654 (defun org-id-open (id)
 655   "Go to the entry with id ID."
 656   (org-mark-ring-push)
 657   (let ((m (org-id-find id 'marker))
 658         cmd)
 659     (unless m
 660       (error "Cannot find entry with ID \"%s\"" id))
 661     ;; Use a buffer-switching command in analogy to finding files
 662     (setq cmd
 663           (or
 664            (cdr
 665             (assq
 666              (cdr (assq 'file org-link-frame-setup))
 667              '((find-file . switch-to-buffer)
 668                (find-file-other-window . switch-to-buffer-other-window)
 669                (find-file-other-frame . switch-to-buffer-other-frame))))
 670            'switch-to-buffer-other-window))
 671     (if (not (equal (current-buffer) (marker-buffer m)))
 672         (funcall cmd (marker-buffer m)))
 673     (goto-char m)
 674     (move-marker m nil)
 675     (org-show-context)))
 676
 677 (org-link-set-parameters "id" :follow #'org-id-open)
 678
 679 (provide 'org-id)
 680
 681 ;; Local variables:
 682 ;; generated-autoload-file: "org-loaddefs.el"
 683 ;; End:
 684
 685 ;;; org-id.el ends here