| blob | 630889425b765fe06e5b9c9f258c49355d9df087 |
1 ;;; vc.el --- drive a version-control system from within Emacs
3 ;; Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
5 ;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
6 ;; Maintainer: ttn@netcom.com
7 ;; Version: 5.5 + CVS hacks by ceder@lysator.liu.se made in Jan-Feb 1994.
9 ;; This file is part of GNU Emacs.
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 2, or (at your option)
14 ;; any later version.
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.
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
23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
25 ;;; Commentary:
27 ;; This mode is fully documented in the Emacs user's manual.
28 ;;
29 ;; This was designed and implemented by Eric Raymond <esr@snark.thyrsus.com>.
30 ;; Paul Eggert <eggert@twinsun.com>, Sebastian Kremer <sk@thp.uni-koeln.de>,
31 ;; and Richard Stallman contributed valuable criticism, support, and testing.
32 ;;
33 ;; Supported version-control systems presently include SCCS and RCS;
34 ;; the RCS lock-stealing code doesn't work right unless you use RCS 5.6.2
35 ;; or newer. Currently (January 1994) that is only a beta test release.
36 ;;
37 ;; The RCS code assumes strict locking. You can support the RCS -x option
38 ;; by adding pairs to the vc-master-templates list.
39 ;;
40 ;; Proper function of the SCCS diff commands requires the shellscript vcdiff
41 ;; to be installed somewhere on Emacs's path for executables.
42 ;;
43 ;; If your site uses the ChangeLog convention supported by Emacs, the
44 ;; function vc-comment-to-change-log should prove a useful checkin hook.
45 ;;
46 ;; This code depends on call-process passing back the subprocess exit
47 ;; status. Thus, you need Emacs 18.58 or later to run it. For the
48 ;; vc-directory command to work properly as documented, you need 19.
49 ;; You also need Emacs 19's ring.el.
50 ;;
51 ;; The vc code maintains some internal state in order to reduce expensive
52 ;; version-control operations to a minimum. Some names are only computed
53 ;; once. If you perform version control operations with RCS/SCCS/CVS while
54 ;; vc's back is turned, or move/rename master files while vc is running,
55 ;; vc may get seriously confused. Don't do these things!
56 ;;
57 ;; Developer's notes on some concurrency issues are included at the end of
58 ;; the file.
60 ;;; Code:
69 minor-mode-alist)))
71 ;; General customization
74 "*Back-end actually used by this interface; may be SCCS or RCS.
79 "*If non-nil, don't delete working files after registering changes.
80 If the back-end is CVS, workfiles are always kept, regardless of the
98 ;;; This is duplicated in diff.el.
102 ;;;###autoload
107 "*List of functions called when a buffer is made writable. See `run-hooks.'
108 This hook is only used when the version control system is CVS. It
109 might be useful for sites who uses locking with CVS, or who uses link
112 ;; Header-insertion hair
120 "*Associate static header string templates with file types. A \%s in the
121 template is replaced with the first string associated with the file's
126 "*Special comment delimiters to be used in generating vc headers only.
127 Add an entry in this list if you need to override the normal comment-start
128 and comment-end variables. This will only be necessary if the mode language
131 ;; Default is to be extra careful for super-user.
133 "*Non-nil means be extra-careful in checkout.
134 Verify that the file really is not locked
137 ;; Variables the user doesn't need to know about.
142 ;; In a log entry buffer, this is a local variable
143 ;; that points to the buffer for which it was made
144 ;; (either a file, or a VC dired buffer).
160 ;; File property caching
163 ;; clear all properties of a given file
167 "Clear all cached file properties and the comment ring."
170 ;; Note: there is potential for minor lossage here if there is an open
171 ;; log buffer with a nonzero local value of vc-comment-ring-index.
174 ;; Random helper functions
184 "Look for a command anywhere on the subprocess-command search path."
197 exec-path)
198 nil)))
201 "Execute a version-control command, notifying user and checking for errors.
202 The command is successful if its exit status does not exceed OKSTATUS.
203 Output from COMMAND goes to buffer *vc*. The last argument of the command is
204 the master name of FILE if LAST is 'MASTER, or the basename of FILE if LAST is
205 'BASE; this is appended to an optional list of FLAGS."
212 status)
220 ;; This is so that command arguments typed in the *vc* buffer will
221 ;; have reasonable defaults.
226 flags)
233 ;; Add vc-path to PATH for the execution of this command.
237 process-environment)))
249 status))
250 )
253 )
255 status)
256 )
258 ;;; Save a bit of the text around POSN in the current buffer, to help
259 ;;; us find the corresponding position again later. This works even
260 ;;; if all markers are destroyed or corrupted.
267 ;;; Return the position of CONTEXT in the current buffer, or nil if we
268 ;;; couldn't find it.
278 ;; Can't use search-backward since the match may continue
279 ;; after point.
281 ;; goto-char doesn't signal an error at
282 ;; beginning of buffer like backward-char would
284 ;; to beginning of OSTRING
288 ;; Most of this was shamelessly lifted from Sebastian Kremer's rcs.el mode.
289 ;; Revert buffer, try to keep point and mark where user expects them in spite
290 ;; of changes because of expanded version-control key words.
291 ;; This is quite important since otherwise typeahead won't work as expected.
295 ;; Use mark-marker to avoid confusion in transient-mark-mode.
298 ;; Make the right thing happen in transient-mark-mode.
300 ;; We may want to reparse the compilation buffer after revert
303 ;; Construct a list; each elt is nil or a buffer
304 ;; iff that buffer is a compilation output buffer
305 ;; that contains markers into the current buffer.
311 compilation-old-error-list
312 compilation-error-list))
325 ;; the actual revisit
328 ;; Reparse affected compilation buffers.
334 ;; Record the position in the compilation buffer of
335 ;; the last error next-error went to.
338 ;; Reparse the error messages as far as they were parsed before.
340 ;; Move the pointer up to find the error we were at before
341 ;; reparsing. Now next-error should properly go to the next one.
347 ;; Restore point and mark
356 ;; Make sure the current buffer and its working file are in sync
357 ;; NOT-URGENT means it is ok to continue if the user says not to save.
363 nil
368 ;; Has the given workfile changed since last checkout?
375 ;; 0 stands for an unknown time; it can't match any mod time.
377 unchanged)))))
380 ;;; If comment is specified, it will be used as an admin or checkin comment.
383 owner version)
386 ;; if there is no master file corresponding, create one
390 ;; if there is no lock on the file, assert one and get it
399 file))
410 )
413 ;; a checked-out version exists, but the user may not own the lock
419 file
421 owner))
423 ;; changes to the master file needs to be merged back into the
424 ;; working file
426 ;; "0" means "added, but not yet committed"
438 "Buffer %s modified; merge file on disc anyhow? "
442 ;; Overlaps detected - what now? Should use some
443 ;; fancy RCS conflict resolving package, or maybe
444 ;; emerge, but for now, simply warn the user with a
445 ;; message.
453 ;; Sites who make link farms to a read-only gold tree (or
454 ;; something similar) can use the hook below to break the
455 ;; sym-link.
458 ;; OK, user owns the lock on the file (or we are running CVS)
462 ;; give luser a chance to save before checking in.
465 ;; Revert if file is unchanged and buffer is too.
466 ;; If buffer is modified, that means the user just said no
467 ;; to saving it; in that case, don't revert,
468 ;; because the user might intend to save
469 ;; after finishing the log entry.
477 ;; DO NOT revert the file without asking the user!
480 ;; user may want to set nonstandard parameters
484 ;; OK, let's do the checkin
486 )))))
489 ;; We've accepted a log comment, now do a vc-next-action using it on all
490 ;; marked files.
498 nil t)
499 )
501 ;; Here's the major entry point.
503 ;;;###autoload
505 "Do the next logical checkin or checkout operation on the current file.
507 For RCS and SCCS files:
508 If the file is not already registered, this registers it for version
509 control and then retrieves a writable, locked copy for editing.
510 If the file is registered and not locked by anyone, this checks out
511 a writable and locked file ready for editing.
512 If the file is checked out and locked by the calling user, this
513 first checks to see if the file has changed since checkout. If not,
514 it performs a revert.
515 If the file has been changed, this pops up a buffer for entry
516 of a log message; when the message has been entered, it checks in the
517 resulting changes along with the log message as change commentary. If
518 the variable `vc-keep-workfiles' is non-nil (which is its default), a
519 read-only copy of the changed file is left in place afterwards.
520 If the file is registered and locked by someone else, you are given
521 the option to steal the lock.
523 For CVS files:
524 If the file is not already registered, this registers it for version
526 If the file is added but not committed, it is committed.
527 If the file has not been changed, neither in your working area or
528 in the repository, a message is printed and nothing is done.
529 If your working file is changed, but the repository file is
530 unchanged, this pops up a buffer for entry of a log message; when the
531 message has been entered, it checks in the resulting changes along
532 with the logmessage as change commentary. A writable file is retained.
533 If the repository file is changed, you are asked if you want to
534 merge in the changes into your working copy.
536 The following is true regardless of which version control system you
537 are using:
539 If you call this from within a VC dired buffer with no files marked,
540 it will operate on the file in the current line.
541 If you call this from within a VC dired buffer, and one or more
542 files are marked, it will accept a log message and then operate on
543 each one. The log message will be used as a comment for any register
544 or checkin operations, but ignored when doing checkouts. Attempted
545 lock steals will raise an error.
547 For checkin, a prefix argument lets you specify the version number to use."
555 "Enter a change comment for the marked files."
564 ;;; These functions help the vc-next-action entry point
567 "Retrieve a writable copy of the latest version of the current buffer's file."
569 )
571 ;;;###autoload
573 "Register the current file into your version-control system."
581 ;; Watch out for new buffers of size 0: the corresponding file
582 ;; does not exist yet, even though buffer-modified-p is nil.
589 buffer-file-name
593 )
596 ;; If the given file is in the current buffer,
597 ;; either revert on it so we see expanded keyworks,
598 ;; or unvisit it (depending on vc-keep-workfiles)
599 ;; NOQUERY if non-nil inhibits confirmation for reverting.
600 ;; NOQUERY should be t *only* if it is known the only difference
601 ;; between the buffer and the file is due to RCS rather than user editing!
612 ;; Accept a comment for an operation on FILE revision REV. If COMMENT
613 ;; is nil, pop up a VC-log buffer, emit MSG, and set the
614 ;; action on close to ACTION; otherwise, do action immediately.
615 ;; Remember the file's buffer in vc-parent-buffer (current one if no file).
616 ;; AFTER-HOOK specifies the local value for vc-log-operation-hook.
642 "Check a file into your version-control system.
643 FILE is the unmodified name of the file. REV should be the base version
644 level to check it in under. COMMENT, if specified, is the checkin comment."
648 nil))
651 "Retrieve a copy of the latest version of the given file."
652 ;; If ftp is on this system and the name matches the ange-ftp format
653 ;; for a remote file, the user is trying something that won't work.
659 )
662 "Steal the lock on the current workfile."
670 file-description owner)))
686 ;; This is called when the notification has been sent.
695 "Check in the file specified by FILE.
696 The optional argument REV may be a string specifying the new version level
697 \(if nil increment the current level). The file is either retained with write
698 permissions zeroed, or deleted (according to the value of `vc-keep-workfiles').
699 If the back-end is CVS, a writable workfile is always kept.
700 COMMENT is a comment string; if omitted, a buffer is
701 popped up to accept a comment."
706 ;;; Here is a checkin hook that may prove useful to sites using the
707 ;;; ChangeLog facility supported by Emacs.
709 "Enter last VC comment into change log file for current buffer's file.
710 Optional arg (interactive prefix) non-nil means prompt for user name and site.
711 Second arg is file name of change log. \
712 If nil, uses `change-log-default-name'."
716 ;; Make sure the defvar for add-log-current-defun-function has been executed
717 ;; before binding it.
721 ;; Don't let add-change-log-entry insert a defun name.
723 end)
724 ;; Call add-log to do half the work.
726 ;; Insert the VC comment, leaving point before it.
729 ;; It starts with an open-paren, as in "(foo): Frobbed."
730 ;; So remove the ": " add-log inserted.
732 ;; Canonicalize the white space between the file name and comment.
734 ;; Indent rest of the text the same way add-log indented the first line.
741 ;; Fill the inserted text, preserving open-parens at bol.
746 ;; Canonicalize the white space at the end of the entry so it is
747 ;; separated from the next entry by a single blank line.
755 "Complete the operation implied by the current log entry."
757 ;; Check and record the comment, if any.
763 ;; Comment too long?
765 ;; Record the comment in the comment ring
769 ))
770 ;; Sync parent buffer in case the user modified it while editing the comment.
771 ;; But not if it is a vc-dired buffer.
776 ;; OK, do it to it
780 vc-log-file
781 vc-log-version
784 ;; save the vc-log-after-operation-hook of log buffer
786 ;; Return to "parent" buffer of this checkin and remove checkin window
791 ;; Now make sure we see the expanded headers
796 ;; Code for access to the comment ring
799 "Cycle backwards through comment history."
807 ;; Initialize the index on the first use of this command
808 ;; so that the first M-p gets index 0, and the first M-n gets
809 ;; index -1.
820 "Cycle forwards through comment history."
825 "Searches backwards through comment history for substring match."
842 "Searches forwards through comment history for substring match."
858 ;; Additional entry points for examining version histories
860 ;;;###autoload
862 "Display diffs between file versions.
863 Normally this compares the current file and buffer with the most recent
864 checked in version of that file. This uses no arguments.
865 With a prefix argument, it reads the file name to use
866 and two version designators specifying which versions to compare."
878 unchanged)
886 ;; Ideally, we'd like at this point to parse the diff so that
887 ;; the buffer effectively goes into compilation mode and we
888 ;; can visit the old and new change locations via next-error.
889 ;; Unfortunately, this is just too painful to do. The basic
890 ;; problem is that the `old' file doesn't exist to be
891 ;; visited. This plays hell with numerous assumptions in
892 ;; the diff.el and compile.el machinery.
904 "For FILE, report diffs between two stored versions REL1 and REL2 of it.
905 If FILE is a directory, generate diffs between versions for all registered
906 files in or below it."
919 " and "
932 )))
937 )
942 ;;;###autoload
944 "Visit version REV of the current buffer in another window.
945 If the current buffer is named `F', the version is named `F.~REV~'.
946 If `F.~REV~' already exists, it is used instead of being re-created."
955 rev))
962 ;; Header-insertion code
964 ;;;###autoload
966 "Insert headers in a file for use with your version-control system.
967 Headers desired are inserted at the start of the buffer, and are pulled from
968 the variable `vc-header-alist'."
987 hdstrings)
992 vc-static-header-alist))
993 )
994 )))))
996 ;; The VC directory submode. Coopt Dired for this.
997 ;; All VC commands get mapped into logical equivalents.
1006 minor-mode-map-alist)))
1009 "The augmented Dired minor mode used in VC directory buffers.
1010 All Dired commands operate normally. Users currently locking listed files
1011 are listed in place of the file's owner and group.
1012 Keystrokes bound to VC commands will execute as though they had been called
1013 on a buffer attached to the file named in the current Dired buffer line."
1018 ;; Hack a directory-listing line, plugging in locking-user info in
1019 ;; place of the user and group info. Should have the beneficial
1020 ;; side-effect of shortening the listing line. Each call starts with
1021 ;; point immediately following the dired mark area on the line to be
1022 ;; hacked.
1023 ;;
1024 ;; Simplest possible one:
1025 ;; (insert (concat x "\t")))
1026 ;;
1027 ;; This code, like dired, assumes UNIX -l format.
1030 ;; This hack is used by the CVS code. See vc-locking-user.
1047 )))
1049 ;;; Note in Emacs 18 the following defun gets overridden
1050 ;;; with the symbol 'vc-directory-18. See below.
1051 ;;;###autoload
1053 "Show version-control status of all files under the current directory."
1058 dired-buf
1059 dired-buf-mod-count)
1068 ;; This uses a semi-documented feature of dired; giving a switch
1069 ;; argument forces the buffer to refresh each time.
1072 dired-listing-switches)
1091 )
1094 ))
1096 ;; Emacs 18 version
1098 "Show version-control status of all files under the current directory."
1121 )
1126 ; Emacs 18 also lacks these.
1130 ;; Named-configuration support for SCCS
1139 ))
1145 ;; (replace-regexp (concat ":" (regexp-quote file) "$") (concat ":" newname))
1150 ))
1153 ;; Return the numeric version corresponding to a named snapshot of file
1154 ;; If name is nil or a version number string it's just passed through
1158 name)
1163 )))
1165 ;; Named-configuration entry points
1168 ;; Return an example of why the current directory is not ready to be snapshot
1169 ;; or nil if no such example exists.
1175 nil))
1177 ;;;###autoload
1179 "Make a snapshot called NAME.
1180 The snapshot is made from all registered files at or below the current
1181 directory. For each file, the version level of its latest
1182 version becomes part of the named configuration."
1191 )))
1193 ;;;###autoload
1195 "Retrieve the snapshot called NAME.
1196 This function fails if any files are locked at or below the current directory
1197 Otherwise, all registered files are checked out (unlocked) at their version
1198 levels in the snapshot."
1208 )))
1210 ;; Miscellaneous other entry points
1212 ;;;###autoload
1214 "List the change log of the current buffer in a window."
1231 )
1233 )
1234 )
1236 ;;;###autoload
1238 "Revert the current buffer's file back to the latest checked-in version.
1239 This asks for confirmation if the buffer contents are not identical
1240 to that version.
1241 If the back-end is CVS, this will give you the most recent revision of
1242 the file on the branch you are editing."
1260 )
1261 )
1263 ;;;###autoload
1265 "Get rid of most recently checked in version of this file.
1266 A prefix argument means do not revert the buffer afterwards."
1275 "Remove your version %s from master? "
1278 nil
1284 ))
1286 ;;;###autoload
1288 "Rename file OLD to NEW, and rename its master file likewise."
1290 ;; There are several ways of renaming files under CVS 1.3, but they all
1291 ;; have serious disadvantages. See the FAQ (available from think.com in
1292 ;; pub/cvs/). I'd rather send the user an error, than do something he might
1293 ;; consider to be wrong. When the famous, long-awaited rename database is
1294 ;; implemented things might change for the better. This is unlikely to occur
1295 ;; until CVS 2.0 is released. --ceder 1994-01-23 21:27:51
1311 ;; This had FILE, I changed it to OLD. -- rms.
1315 oldmaster
1329 vc-master-templates)
1333 ; ?? Renaming a file might change its contents due to keyword expansion.
1334 ; We should really check out a new copy if the old copy was precisely equal
1335 ; to some checked in version. However, testing for this is tricky....
1341 ;; This had FILE, I changed it to OLD. -- rms.
1344 nil ;RCS
1345 nil ;CVS
1346 )
1347 )
1349 ;;;###autoload
1351 "Find change log file and add entries from recent RCS logs.
1352 The mark is left at the end of the text prepended to the change log.
1353 With prefix arg of C-u, only find log entries for the current buffer's file.
1354 With any numeric prefix arg, find log entries for all files currently visited.
1355 Otherwise, find log entries for all registered files in the default directory.
1356 From a program, any arguments are passed to the `rcs2log' script."
1363 file)
1369 files))
1377 f)))
1390 "-n"
1393 user-mail-address
1398 f
1400 args))))
1403 ;; Functions for querying the master and lock files.
1409 ;; Use PATTERNS to parse information out of the current buffer
1410 ;; by matching each regular expression in the list and returning \\1.
1411 ;; If a regexp has two tag brackets, assume the second is a date
1412 ;; field and we want the most recent entry matching the template.
1413 ;; If FILE and PROPERTIES are given, the latter must be a list of
1414 ;; properties of the same length as PATTERNS; each property is assigned
1415 ;; the corresponding value.
1427 latest-val))
1434 value)
1436 patterns)
1437 )
1440 ;; Search for information in a master file.
1453 )
1457 properties))
1458 )
1459 )
1462 ;; Search for information in log program output
1471 )
1472 )
1476 properties))
1477 )
1478 )
1481 "Return the name of the person currently holding a lock on FILE.
1482 Return nil if there is no such person.
1483 Under CVS, a file is considered locked if it has been modified since it
1484 was checked out. Under CVS, this will sometimes return the uid of
1485 the owner of the file (as a number) instead of a string."
1490 nil
1491 ;; The expression below should return the username of the owner
1492 ;; of the file. It doesn't. It returns the username if it is
1493 ;; you, or otherwise the UID of the owner of the file. The
1494 ;; return value from this function is only used by
1495 ;; vc-dired-reformat-line, and it does the proper thing if a UID
1496 ;; is returned.
1497 ;;
1498 ;; The *proper* way to fix this would be to implement a built-in
1499 ;; function in Emacs, say, (username UID), that returns the
1500 ;; username of a given UID.
1501 ;;
1502 ;; The result of this hack is that vc-directory will print the
1503 ;; name of the owner of the file for any files that are
1504 ;; modified.
1508 uid))))
1514 file))))
1516 ;; This implementation assumes that any file which is under version
1517 ;; control and has -rw-r--r-- is locked by its owner. This is true
1518 ;; for both RCS and SCCS, which keep unlocked files at -r--r--r--.
1519 ;; We have to be careful not to exclude files with execute bits on;
1520 ;; scripts can be under version control too. Also, we must ignore
1521 ;; the group-read and other-read bits, since paranoid users turn them off.
1522 ;; This hack wins because calls to the very expensive vc-fetch-properties
1523 ;; function only have to be made if (a) the file is locked by someone
1524 ;; other than the current user, or (b) some untoward manipulation
1525 ;; behind vc's back has changed the owner or the `group' or `other'
1526 ;; write bits.
1529 nil)
1537 ;; The slow but reliable version
1542 ;; Return version level of the latest version of FILE
1547 ;; Return version level of the latest version of FILE checked in by you
1551 ;; Collect back-end-dependent stuff here
1552 ;;
1553 ;; Everything eventually funnels through these functions. To implement
1554 ;; support for a new version-control system, add another branch to the
1555 ;; vc-backend-dispatch macro and fill it in in each call. The variable
1556 ;; vc-master-templates in vc-hooks.el will also have to change.
1559 "Execute FORM1, FORM2 or FORM3 depending whether we're using SCCS, RCS or CVS.
1560 If FORM3 is RCS, use FORM2 even if we are using CVS. (CVS shares some code
1561 with RCS)."
1568 )))
1571 ;; Generate lock file name corresponding to FILE
1574 master
1578 "p."
1583 ;; Re-fetch all properties associated with the given file.
1584 ;; Currently these properties are:
1585 ;; vc-locking-user
1586 ;; vc-locked-version
1587 ;; vc-latest-version
1588 ;; vc-your-latest-version
1590 file
1591 ;; SCCS
1597 file
1604 )
1605 file
1607 )
1608 ;; RCS
1619 vc-latest-version vc-your-latest-version))
1620 ;; CVS
1621 ;; Don't fetch vc-locking-user and vc-locked-version here, since they
1622 ;; should always be nil anyhow. Don't fetch vc-your-latest-version, since
1623 ;; that is done in vc-find-cvs-master.
1626 ;; CVS 1.3 says "RCS Version:", other releases "RCS Revision:",
1627 ;; and CVS 1.4a1 says "Repository revision:". The regexp below
1628 ;; matches much more, but because of the way vc-log-info is
1629 ;; implemented it is impossible to use additional groups.
1632 ))
1635 ;; Where the master and lock files for the current directory are kept
1639 vc-default-back-end
1643 ;; Register a file into the version-control system
1644 ;; Automatically retrieves a read-only version of the file with
1645 ;; keywords expanded if vc-keep-workfiles is non-nil, otherwise
1646 ;; it deletes the workfile.
1661 "-fb"
1675 file))
1678 "add"
1681 )))
1683 )
1686 ;; Retrieve a copy of a saved version into a workfile
1691 ;; Some SCCS implementations allow checking out directly to a
1692 ;; file using the -G option, but then some don't so use the
1693 ;; least common denominator approach and use the -p option
1694 ;; ala RCS.
1702 ;; Some shells make the "" dummy argument into $0
1703 ;; while others use the shell's name as $0 and
1704 ;; use the "" as $1. The if-statement
1705 ;; converts the latter case to the former.
1712 filename
1721 ;; RCS doesn't let us check out into arbitrary file names directly.
1722 ;; Use `co -p' and make stdout point to the correct file.
1730 ;; See the SCCS case, above, regarding the if-statement.
1737 filename
1746 ;; CVS is much like RCS
1754 workfile
1761 file))
1762 )
1766 )
1775 nil ;; RCS
1777 )
1780 ;; Register changes to FILE as level REV with explanatory COMMENT.
1781 ;; Automatically retrieves a read-only version of the file with
1782 ;; keywords expanded if vc-keep-workfiles is non-nil, otherwise
1783 ;; it deletes the workfile.
1786 ;; Change buffers to get local value of vc-checkin-switches.
1793 vc-checkin-switches)
1796 )
1800 vc-checkin-switches)
1804 vc-checkin-switches)
1807 ))
1810 )
1813 ;; Revert file to latest checked-in version.
1816 file
1825 )
1828 )
1831 ;; Steal the lock on the current workfile. Needs RCS 5.6.2 or later for -M.
1837 )
1841 )
1844 )
1847 ;; Undo the latest checkin. Note: this code will have to get a lot
1848 ;; smarter when we support multiple branches.
1854 )
1856 )
1859 ;; Print change log associated with FILE to buffer *vc*.
1861 file
1867 ;; Assign to a FILE's latest version a given NAME.
1872 )
1873 )
1876 ;; Get a difference report between two versions of FILE.
1877 ;; Get only a brief comparison report if CMP, a difference report otherwise.
1884 ;; SCCS and RCS shares a lot of code.
1887 "vcdiff"
1890 "-q"
1895 diff-switches
1898 ;; Some RCS versions don't understand "--brief"; work around this.
1902 status)))
1903 ;; CVS is different.
1904 ;; cmp is not yet implemented -- we always do a full diff.
1907 ;; This file is added but not yet committed; there is no master file.
1908 ;; diff it against /dev/null.
1914 diff-switches
1921 diff-switches
1927 ;; Merge in any new changes made to FILE.
1929 file
1933 ))
1936 "Check if the current file has any headers in it."
1942 (re-search-forward "\\$[A-Za-z\300-\326\330-\366\370-\377]+\\(: [\t -#%-\176\240-\377]*\\)?\\$" nil t) ;; RCS
1944 )
1945 ))
1947 ;; Back-end-dependent stuff ends here.
1949 ;; Set up key bindings for use while editing log messages
1952 "Minor mode for driving version-control tools.
1953 These bindings are added to the global keymap when you enter this mode:
1966 While you are entering a change log message for a version, the following
1967 additional bindings will be in effect.
1971 Whenever you do a checkin, your log comment is added to a ring of
1972 saved comments. These can be recalled as follows:
1979 Entry to the change-log submode calls the value of text-mode-hook, then
1980 the value of vc-log-mode-hook.
1982 Global user options:
1983 vc-initial-comment If non-nil, require user to enter a change
1984 comment upon first checkin of the file.
1986 vc-keep-workfiles Non-nil value prevents workfiles from being
1987 deleted when changes are checked in
1989 vc-suppress-confirm Suppresses some confirmation prompts,
1990 notably for reversions.
1992 vc-header-alist Which keywords to insert when adding headers
1995 RCS and CVS.
1997 vc-static-header-alist By default, version headers inserted in C files
1998 get stuffed in a static string area so that
1999 ident(RCS/CVS) or what(SCCS) can see them in
2000 the compiled object code. You can override
2001 this by setting this variable to nil, or change
2002 the header template by changing it.
2004 vc-command-messages if non-nil, display run messages from the
2005 actual version-control utilities (this is
2006 intended primarily for people hacking vc
2007 itself).
2008 "
2021 )
2023 ;; Initialization code, to be done just once at load-time
2025 nil
2032 )
2034 ;;; These things should probably be generally available
2037 "Walk recursively through default directory.
2038 Invoke FUNC f ARGS on each non-directory file f underneath it."
2060 ;;; DEVELOPER'S NOTES ON CONCURRENCY PROBLEMS IN THIS CODE
2061 ;;;
2062 ;;; These may be useful to anyone who has to debug or extend the package.
2063 ;;;
2064 ;;; A fundamental problem in VC is that there are time windows between
2065 ;;; vc-next-action's computations of the file's version-control state and
2066 ;;; the actions that change it. This is a window open to lossage in a
2067 ;;; multi-user environment; someone else could nip in and change the state
2068 ;;; of the master during it.
2069 ;;;
2070 ;;; The performance problem is that rlog/prs calls are very expensive; we want
2071 ;;; to avoid them as much as possible.
2072 ;;;
2073 ;;; ANALYSIS:
2074 ;;;
2075 ;;; The performance problem, it turns out, simplifies in practice to the
2076 ;;; problem of making vc-locking-user fast. The two other functions that call
2077 ;;; prs/rlog will not be so commonly used that the slowdown is a problem; one
2078 ;;; makes snapshots, the other deletes the calling user's last change in the
2079 ;;; master.
2080 ;;;
2081 ;;; The race condition implies that we have to either (a) lock the master
2082 ;;; during the entire execution of vc-next-action, or (b) detect and
2083 ;;; recover from errors resulting from dispatch on an out-of-date state.
2084 ;;;
2085 ;;; Alternative (a) appears to be unfeasible. The problem is that we can't
2086 ;;; guarantee that the lock will ever be removed. Suppose a user starts a
2087 ;;; checkin, the change message buffer pops up, and the user, having wandered
2088 ;;; off to do something else, simply forgets about it?
2089 ;;;
2090 ;;; Alternative (b), on the other hand, works well with a cheap way to speed up
2091 ;;; vc-locking-user. Usually, if a file is registered, we can read its locked/
2092 ;;; unlocked state and its current owner from its permissions.
2093 ;;;
2094 ;;; This shortcut will fail if someone has manually changed the workfile's
2095 ;;; permissions; also if developers are munging the workfile in several
2096 ;;; directories, with symlinks to a master (in this latter case, the
2097 ;;; permissions shortcut will fail to detect a lock asserted from another
2098 ;;; directory).
2099 ;;;
2100 ;;; Note that these cases correspond exactly to the errors which could happen
2101 ;;; because of a competing checkin/checkout race in between two instances of
2102 ;;; vc-next-action.
2103 ;;;
2104 ;;; For VC's purposes, a workfile/master pair may have the following states:
2105 ;;;
2106 ;;; A. Unregistered. There is a workfile, there is no master.
2107 ;;;
2108 ;;; B. Registered and not locked by anyone.
2109 ;;;
2110 ;;; C. Locked by calling user and unchanged.
2111 ;;;
2112 ;;; D. Locked by the calling user and changed.
2113 ;;;
2114 ;;; E. Locked by someone other than the calling user.
2115 ;;;
2116 ;;; This makes for 25 states and 20 error conditions. Here's the matrix:
2117 ;;;
2118 ;;; VC's idea of state
2119 ;;; |
2120 ;;; V Actual state RCS action SCCS action Effect
2121 ;;; A B C D E
2122 ;;; A . 1 2 3 4 ci -u -t- admin -fb -i<file> initial admin
2123 ;;; B 5 . 6 7 8 co -l get -e checkout
2124 ;;; C 9 10 . 11 12 co -u unget; get revert
2125 ;;; D 13 14 15 . 16 ci -u -m<comment> delta -y<comment>; get checkin
2126 ;;; E 17 18 19 20 . rcs -u -M ; rcs -l unget -n ; get -g steal lock
2127 ;;;
2128 ;;; All commands take the master file name as a last argument (not shown).
2129 ;;;
2130 ;;; In the discussion below, a "self-race" is a pathological situation in
2131 ;;; which VC operations are being attempted simultaneously by two or more
2132 ;;; Emacsen running under the same username.
2133 ;;;
2134 ;;; The vc-next-action code has the following windows:
2135 ;;;
2136 ;;; Window P:
2137 ;;; Between the check for existence of a master file and the call to
2138 ;;; admin/checkin in vc-buffer-admin (apparent state A). This window may
2139 ;;; never close if the initial-comment feature is on.
2140 ;;;
2141 ;;; Window Q:
2142 ;;; Between the call to vc-workfile-unchanged-p in and the immediately
2143 ;;; following revert (apparent state C).
2144 ;;;
2145 ;;; Window R:
2146 ;;; Between the call to vc-workfile-unchanged-p in and the following
2147 ;;; checkin (apparent state D). This window may never close.
2148 ;;;
2149 ;;; Window S:
2150 ;;; Between the unlock and the immediately following checkout during a
2151 ;;; revert operation (apparent state C). Included in window Q.
2152 ;;;
2153 ;;; Window T:
2154 ;;; Between vc-locking-user and the following checkout (apparent state B).
2155 ;;;
2156 ;;; Window U:
2157 ;;; Between vc-locking-user and the following revert (apparent state C).
2158 ;;; Includes windows Q and S.
2159 ;;;
2160 ;;; Window V:
2161 ;;; Between vc-locking-user and the following checkin (apparent state
2162 ;;; D). This window may never be closed if the user fails to complete the
2163 ;;; checkin message. Includes window R.
2164 ;;;
2165 ;;; Window W:
2166 ;;; Between vc-locking-user and the following steal-lock (apparent
2167 ;;; state E). This window may never close if the user fails to complete
2168 ;;; the steal-lock message. Includes window X.
2169 ;;;
2170 ;;; Window X:
2171 ;;; Between the unlock and the immediately following re-lock during a
2172 ;;; steal-lock operation (apparent state E). This window may never cloce
2173 ;;; if the user fails to complete the steal-lock message.
2174 ;;;
2175 ;;; Errors:
2176 ;;;
2177 ;;; Apparent state A ---
2178 ;;;
2179 ;;; 1. File looked unregistered but is actually registered and not locked.
2180 ;;;
2181 ;;; Potential cause: someone else's admin during window P, with
2182 ;;; caller's admin happening before their checkout.
2183 ;;;
2184 ;;; RCS: ci will fail with a "no lock set by <user>" message.
2185 ;;; SCCS: admin will fail with error (ad19).
2186 ;;;
2187 ;;; We can let these errors be passed up to the user.
2188 ;;;
2189 ;;; 2. File looked unregistered but is actually locked by caller, unchanged.
2190 ;;;
2191 ;;; Potential cause: self-race during window P.
2192 ;;;
2193 ;;; RCS: will revert the file to the last saved version and unlock it.
2194 ;;; SCCS: will fail with error (ad19).
2195 ;;;
2196 ;;; Either of these consequences is acceptable.
2197 ;;;
2198 ;;; 3. File looked unregistered but is actually locked by caller, changed.
2199 ;;;
2200 ;;; Potential cause: self-race during window P.
2201 ;;;
2202 ;;; RCS: will register the caller's workfile as a delta with a
2203 ;;; null change comment (the -t- switch will be ignored).
2204 ;;; SCCS: will fail with error (ad19).
2205 ;;;
2206 ;;; 4. File looked unregistered but is locked by someone else.
2207 ;;;
2208 ;;; Potential cause: someone else's admin during window P, with
2209 ;;; caller's admin happening *after* their checkout.
2210 ;;;
2211 ;;; RCS: will fail with a "no lock set by <user>" message.
2212 ;;; SCCS: will fail with error (ad19).
2213 ;;;
2214 ;;; We can let these errors be passed up to the user.
2215 ;;;
2216 ;;; Apparent state B ---
2217 ;;;
2218 ;;; 5. File looked registered and not locked, but is actually unregistered.
2219 ;;;
2220 ;;; Potential cause: master file got nuked during window P.
2221 ;;;
2222 ;;; RCS: will fail with "RCS/<file>: No such file or directory"
2223 ;;; SCCS: will fail with error ut4.
2224 ;;;
2225 ;;; We can let these errors be passed up to the user.
2226 ;;;
2227 ;;; 6. File looked registered and not locked, but is actually locked by the
2228 ;;; calling user and unchanged.
2229 ;;;
2230 ;;; Potential cause: self-race during window T.
2231 ;;;
2232 ;;; RCS: in the same directory as the previous workfile, co -l will fail
2233 ;;; with "co error: writable foo exists; checkout aborted". In any other
2234 ;;; directory, checkout will succeed.
2235 ;;; SCCS: will fail with ge17.
2236 ;;;
2237 ;;; Either of these consequences is acceptable.
2238 ;;;
2239 ;;; 7. File looked registered and not locked, but is actually locked by the
2240 ;;; calling user and changed.
2241 ;;;
2242 ;;; As case 6.
2243 ;;;
2244 ;;; 8. File looked registered and not locked, but is actually locked by another
2245 ;;; user.
2246 ;;;
2247 ;;; Potential cause: someone else checks it out during window T.
2248 ;;;
2249 ;;; RCS: co error: revision 1.3 already locked by <user>
2250 ;;; SCCS: fails with ge4 (in directory) or ut7 (outside it).
2251 ;;;
2252 ;;; We can let these errors be passed up to the user.
2253 ;;;
2254 ;;; Apparent state C ---
2255 ;;;
2256 ;;; 9. File looks locked by calling user and unchanged, but is unregistered.
2257 ;;;
2258 ;;; As case 5.
2259 ;;;
2260 ;;; 10. File looks locked by calling user and unchanged, but is actually not
2261 ;;; locked.
2262 ;;;
2263 ;;; Potential cause: a self-race in window U, or by the revert's
2264 ;;; landing during window X of some other user's steal-lock or window S
2265 ;;; of another user's revert.
2266 ;;;
2267 ;;; RCS: succeeds, refreshing the file from the identical version in
2268 ;;; the master.
2269 ;;; SCCS: fails with error ut4 (p file nonexistent).
2270 ;;;
2271 ;;; Either of these consequences is acceptable.
2272 ;;;
2273 ;;; 11. File is locked by calling user. It looks unchanged, but is actually
2274 ;;; changed.
2275 ;;;
2276 ;;; Potential cause: the file would have to be touched by a self-race
2277 ;;; during window Q.
2278 ;;;
2279 ;;; The revert will succeed, removing whatever changes came with
2280 ;;; the touch. It is theoretically possible that work could be lost.
2281 ;;;
2282 ;;; 12. File looks like it's locked by the calling user and unchanged, but
2283 ;;; it's actually locked by someone else.
2284 ;;;
2285 ;;; Potential cause: a steal-lock in window V.
2286 ;;;
2287 ;;; RCS: co error: revision <rev> locked by <user>; use co -r or rcs -u
2288 ;;; SCCS: fails with error un2
2289 ;;;
2290 ;;; We can pass these errors up to the user.
2291 ;;;
2292 ;;; Apparent state D ---
2293 ;;;
2294 ;;; 13. File looks like it's locked by the calling user and changed, but it's
2295 ;;; actually unregistered.
2296 ;;;
2297 ;;; Potential cause: master file got nuked during window P.
2298 ;;;
2299 ;;; RCS: Checks in the user's version as an initial delta.
2300 ;;; SCCS: will fail with error ut4.
2301 ;;;
2302 ;;; This case is kind of nasty. It means VC may fail to detect the
2303 ;;; loss of previous version information.
2304 ;;;
2305 ;;; 14. File looks like it's locked by the calling user and changed, but it's
2306 ;;; actually unlocked.
2307 ;;;
2308 ;;; Potential cause: self-race in window V, or the checkin happening
2309 ;;; during the window X of someone else's steal-lock or window S of
2310 ;;; someone else's revert.
2311 ;;;
2312 ;;; RCS: ci will fail with "no lock set by <user>".
2313 ;;; SCCS: delta will fail with error ut4.
2314 ;;;
2315 ;;; 15. File looks like it's locked by the calling user and changed, but it's
2316 ;;; actually locked by the calling user and unchanged.
2317 ;;;
2318 ;;; Potential cause: another self-race --- a whole checkin/checkout
2319 ;;; sequence by the calling user would have to land in window R.
2320 ;;;
2321 ;;; SCCS: checks in a redundant delta and leaves the file unlocked as usual.
2322 ;;; RCS: reverts to the file state as of the second user's checkin, leaving
2323 ;;; the file unlocked.
2324 ;;;
2325 ;;; It is theoretically possible that work could be lost under RCS.
2326 ;;;
2327 ;;; 16. File looks like it's locked by the calling user and changed, but it's
2328 ;;; actually locked by a different user.
2329 ;;;
2330 ;;; RCS: ci error: no lock set by <user>
2331 ;;; SCCS: unget will fail with error un2
2332 ;;;
2333 ;;; We can pass these errors up to the user.
2334 ;;;
2335 ;;; Apparent state E ---
2336 ;;;
2337 ;;; 17. File looks like it's locked by some other user, but it's actually
2338 ;;; unregistered.
2339 ;;;
2340 ;;; As case 13.
2341 ;;;
2342 ;;; 18. File looks like it's locked by some other user, but it's actually
2343 ;;; unlocked.
2344 ;;;
2345 ;;; Potential cause: someone released a lock during window W.
2346 ;;;
2347 ;;; RCS: The calling user will get the lock on the file.
2348 ;;; SCCS: unget -n will fail with cm4.
2349 ;;;
2350 ;;; Either of these consequences will be OK.
2351 ;;;
2352 ;;; 19. File looks like it's locked by some other user, but it's actually
2353 ;;; locked by the calling user and unchanged.
2354 ;;;
2355 ;;; Potential cause: the other user relinquishing a lock followed by
2356 ;;; a self-race, both in window W.
2357 ;;;
2358 ;;; Under both RCS and SCCS, both unlock and lock will succeed, making
2359 ;;; the sequence a no-op.
2360 ;;;
2361 ;;; 20. File looks like it's locked by some other user, but it's actually
2362 ;;; locked by the calling user and changed.
2363 ;;;
2364 ;;; As case 19.
2365 ;;;
2366 ;;; PROBLEM CASES:
2367 ;;;
2368 ;;; In order of decreasing severity:
2369 ;;;
2370 ;;; Cases 11 and 15 under RCS are the only one that potentially lose work.
2371 ;;; They would require a self-race for this to happen.
2372 ;;;
2373 ;;; Case 13 in RCS loses information about previous deltas, retaining
2374 ;;; only the information in the current workfile. This can only happen
2375 ;;; if the master file gets nuked in window P.
2376 ;;;
2377 ;;; Case 3 in RCS and case 15 under SCCS insert a redundant delta with
2378 ;;; no change comment in the master. This would require a self-race in
2379 ;;; window P or R respectively.
2380 ;;;
2381 ;;; Cases 2, 10, 19 and 20 do extra work, but make no changes.
2382 ;;;
2383 ;;; Unfortunately, it appears to me that no recovery is possible in these
2384 ;;; cases. They don't yield error messages, so there's no way to tell that
2385 ;;; a race condition has occurred.
2386 ;;;
2387 ;;; All other cases don't change either the workfile or the master, and
2388 ;;; trigger command errors which the user will see.
2389 ;;;
2390 ;;; Thus, there is no explicit recovery code.
2392 ;;; vc.el ends here