| blob | 9b69f3be6dcb6c14f53b307e153b64b0be140fc8 |
1 ;;; vc.el --- drive a version-control system from within Emacs
3 ;; Copyright (C) 1992,93,94,95,96,97,98,2000 Free Software Foundation, Inc.
5 ;; Author: FSF (see below for full credits)
6 ;; Maintainer: Andre Spiegel <spiegel@gnu.org>
8 ;; $Id: vc.el,v 1.277 2000/10/04 09:48:37 spiegel Exp $
10 ;; This file is part of GNU Emacs.
12 ;; GNU Emacs is free software; you can redistribute it and/or modify
13 ;; it under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; any later version.
17 ;; GNU Emacs is distributed in the hope that it will be useful,
18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;; GNU General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs; see the file COPYING. If not, write to the
24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
25 ;; Boston, MA 02111-1307, USA.
27 ;;; Credits:
29 ;; VC was initially designed and implemented by Eric S. Raymond
30 ;; <esr@snark.thyrsus.com>. Over the years, many people have
31 ;; contributed substantial amounts of work to VC. These include:
32 ;; Per Cederqvist <ceder@lysator.liu.se>
33 ;; Paul Eggert <eggert@twinsun.com>
34 ;; Sebastian Kremer <sk@thp.uni-koeln.de>
35 ;; Martin Lorentzson <martinl@gnu.org>
36 ;; Dave Love <d.love@gnu.org>
37 ;; Stefan Monnier <monnier@cs.yale.edu>
38 ;; Andre Spiegel <spiegel@gnu.org>
39 ;; Richard Stallman <rms@gnu.org>
40 ;; ttn@netcom.com
42 ;;; Commentary:
44 ;; This mode is fully documented in the Emacs user's manual.
45 ;;
46 ;; Supported version-control systems presently include SCCS, RCS, and CVS.
47 ;;
48 ;; Some features will not work with old RCS versions. Where
49 ;; appropriate, VC finds out which version you have, and allows or
50 ;; disallows those features (stealing locks, for example, works only
51 ;; from 5.6.2 onwards).
52 ;; Even initial checkins will fail if your RCS version is so old that ci
53 ;; doesn't understand -t-; this has been known to happen to people running
54 ;; NExTSTEP 3.0.
55 ;;
56 ;; You can support the RCS -x option by customizing vc-rcs-master-templates.
57 ;;
58 ;; Proper function of the SCCS diff commands requires the shellscript vcdiff
59 ;; to be installed somewhere on Emacs's path for executables.
60 ;;
61 ;; If your site uses the ChangeLog convention supported by Emacs, the
62 ;; function vc-comment-to-change-log should prove a useful checkin hook.
63 ;;
64 ;; The vc code maintains some internal state in order to reduce expensive
65 ;; version-control operations to a minimum. Some names are only computed
66 ;; once. If you perform version control operations with RCS/SCCS/CVS while
67 ;; vc's back is turned, or move/rename master files while vc is running,
68 ;; vc may get seriously confused. Don't do these things!
69 ;;
70 ;; Developer's notes on some concurrency issues are included at the end of
71 ;; the file.
73 ;;; Code:
75 ;;;;;;;;;;;;;;;;; Backend-specific functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
76 ;;
77 ;; for each operation FUN, the backend should provide a function vc-BACKEND-FUN.
78 ;; Operations marked with a `-' instead of a `*' are optional.
80 ;; * registered (file)
81 ;; * state (file)
82 ;; - state-heuristic (file)
83 ;; The default behavior delegates to `state'.
84 ;; - dir-state (dir)
85 ;; * checkout-model (file)
86 ;; - mode-line-string (file)
87 ;; * workfile-version (file)
88 ;; * revert (file)
89 ;; - merge-news (file)
90 ;; Only needed if state `needs-merge' is possible.
91 ;; - merge (file rev1 rev2)
92 ;; - steal-lock (file &optional version)
93 ;; Only required if files can be locked by somebody else.
94 ;; * register (file rev comment)
95 ;; * unregister (file backend)
96 ;; - receive-file (file rev)
97 ;; - responsible-p (file)
98 ;; Should also work if FILE is a directory (ends with a slash).
99 ;; - could-register (file)
100 ;; * checkout (file writable &optional rev destfile)
101 ;; Checkout revision REV of FILE into DESTFILE.
102 ;; DESTFILE defaults to FILE.
103 ;; The file should be made writable if WRITABLE is non-nil.
104 ;; REV can be nil (BASE) or "" (HEAD) or any other revision.
105 ;; * checkin (file rev comment)
106 ;; - logentry-check ()
107 ;; * diff (file &optional rev1 rev2)
108 ;; Insert the diff for FILE into the current buffer.
109 ;; REV1 should default to workfile-version.
110 ;; REV2 should default to the current workfile
111 ;; Return a status of either 0 (i.e. no diff) or 1 (i.e. either non-empty
112 ;; diff or the diff is run asynchronously).
113 ;; - workfile-unchanged-p (file)
114 ;; Return non-nil if FILE is unchanged from its current workfile version.
115 ;; This function should do a brief comparison of FILE's contents
116 ;; with those of the master version. If the backend does not have
117 ;; such a brief-comparison feature, the default implementation of this
118 ;; function can be used, which delegates to a full vc-BACKEND-diff.
119 ;; - clear-headers ()
120 ;; * check-headers ()
121 ;; - dired-state-info (file)
122 ;; - create-snapshot (dir name branchp)
123 ;; Take a snapshot of the current state of files under DIR and name it NAME.
124 ;; This should make sure that files are up-to-date before proceeding
125 ;; with the action.
126 ;; DIR can also be a file and if BRANCHP is specified, NAME
127 ;; should be created as a branch and DIR should be checked out under
128 ;; this new branch. The default behavior does not support branches
129 ;; but does a sanity check, a tree traversal and for each file calls
130 ;; `assign-name'.
131 ;; * assign-name (file name)
132 ;; Give name NAME to the current version of FILE, assuming it is
133 ;; up-to-date. Only used by the default version of `create-snapshot'.
134 ;; - retrieve-snapshot (dir name update)
135 ;; Retrieve a named snapshot of all registered files at or below DIR.
136 ;; If UPDATE is non-nil, then update buffers of any files in the snapshot
137 ;; that are currently visited.
138 ;; * print-log (file)
139 ;; Insert the revision log of FILE into the current buffer.
140 ;; - show-log-entry (version)
141 ;; - wash-log (file)
142 ;; Remove all non-comment information from the output of print-log
143 ;; - comment-history (file)
144 ;; - update-changelog (files)
145 ;; Find changelog entries for FILES, or for all files at or below
146 ;; the default-directory if FILES is nil.
147 ;; * latest-on-branch-p (file)
148 ;; - cancel-version (file writable)
149 ;; - rename-file (old new)
150 ;; - annotate-command (file buf)
151 ;; - annotate-difference (pos)
152 ;; Only required if `annotate-command' is defined for the backend.
165 minor-mode-alist)))
167 ;; General customization
170 "Version-control system in Emacs."
174 "*If non-nil, treat user as expert; suppress yes-no prompts on some things."
179 "*If non-nil, delete the *VC-log* buffer and window after each logical action.
180 If nil, bury that buffer instead.
181 This is most useful if you have multiple windows on a frame and would like to
182 preserve the setting."
187 "*If non-nil, prompt for initial comment when a file is registered."
192 "*A string used as the default version number when a new file is registered.
199 "*If non-nil, display run messages from back-end commands."
204 "*A string or list of strings specifying extra switches for checkin.
210 string))
214 "*A string or list of strings specifying extra switches for checkout.
220 string))
224 "*A string or list of strings; extra switches for registering a file.
230 string))
234 "*Switches passed to `ls' for vc-dired. MUST contain the `l' option."
240 "*If non-nil, show directory trees recursively in VC Dired."
246 "*If non-nil, show only locked files in VC Dired."
252 "*List of directory names to be ignored while recursively walking file trees."
259 ;;; This is duplicated in diff.el.
263 ;;;###autoload
265 "*Normal hook (list of functions) run after a checkin is done.
266 See `run-hooks'."
271 ;;;###autoload
273 "*Normal hook (list of functions) run before a file gets checked in.
274 See `run-hooks'."
279 "*Normal hook run by `vc-backend-logentry-check'.
280 Use this to impose your own rules on the entry in addition to any the
281 version control backend imposes itself."
285 ;; Annotate customization
305 Ages are given in units of 2**-16 seconds.
306 Default is eighteen steps using a twenty day increment."
311 "*Color for lines older than CAR of last cons in `vc-annotate-color-map'."
317 Default color is used if nil."
322 "*Menu elements for the mode-specific menu of VC-Annotate mode.
323 List of factors, used to expand/compress the time scale. See `vc-annotate'."
327 ;; vc-annotate functionality (CVS only).
334 m)
340 ;; Header-insertion hair
345 "*Associate static header string templates with file types.
346 A \%s in the template is replaced with the first string associated with
347 the file's version control type in `vc-header-alist'."
355 "*Special comment delimiters to be used in generating vc headers only.
356 Add an entry in this list if you need to override the normal `comment-start'
357 and `comment-end' variables. This will only be necessary if the mode language
358 is sensitive to blank lines."
365 ;; Default is to be extra careful for super-user.
366 ;; TODO: This variable is no longer used; the corresponding checks
367 ;; are always done now. If that turns out to be fast enough,
368 ;; the variable can be obsoleted.
370 "*Non-nil means be extra-careful in checkout.
371 Verify that the file really is not locked
372 and that its contents match what the master file says."
376 \f
377 ;;; The main keymap
396 map))
399 ;; Initialization code, to be done just once at load-time
407 map))
408 ;; Compatibility with old name. Should we bother ?
411 \f
412 ;; Variables the user doesn't need to know about.
418 ;; In a log entry buffer, this is a local variable
419 ;; that points to the buffer for which it was made
420 ;; (either a file, or a VC dired buffer).
436 ;;; functions that operate on RCS revision numbers. This code should
437 ;;; also be moved into the backends. It stays for now, however, since
438 ;;; it is used in code below.
440 "Return t if REV is a revision on the trunk."
444 "Return t if REV is a branch revision."
448 "Return the branch part of a revision number REV."
452 "Return the minor version number of a revision number REV."
457 "Guess the version number immediately preceding REV."
461 ;; version does probably not start a branch or release
464 ;; we are at the beginning of the trunk --
465 ;; don't know anything to return here
466 ""
467 ;; we are at the beginning of a branch --
468 ;; return version of starting point
471 ;; File property caching
474 "Clear all cached file properties and the comment ring."
477 ;; Note: there is potential for minor lossage here if there is an open
478 ;; log buffer with a nonzero local value of vc-comment-ring-index.
482 "Execute FORM, then set per-file properties for FILE,
483 but only those that have not been set during the execution of FORM.
484 SETTINGS is a list of two-element lists, each of which has the
485 form (PROPERTY . VALUE)."
488 ,form
496 ;; Random helper functions
502 ;;; Two macros for elisp programming
503 ;;;###autoload
505 "Check out a writable copy of FILE if necessary and execute the body.
506 Check in FILE with COMMENT (a string) after BODY has been executed.
507 FILE is passed through `expand-file-name'; BODY executed within
508 `save-excursion'. If FILE is not under version control, or locked by
509 somebody else, signal error."
521 ;;;###autoload
523 "Edit FILE under version control, executing body.
524 Checkin with COMMENT after executing BODY.
525 This macro uses `with-vc-file', passing args to it.
526 However, before executing BODY, find FILE, and after BODY, save buffer."
530 ,@body
534 "Make sure that the current buffer visits a version-controlled file."
551 "An alternative output filter for async process P.
552 The only difference with the default filter is to insert S after markers."
561 "Prepare BUF for executing a VC command and make it the current buffer.
576 "Eval CODE when the current buffer's process is done.
577 If the current buffer has no process, just evaluate CODE.
578 Else, add CODE to the process' sentinel."
581 ;; If there's no background process, just execute the code.
583 ;; If the background process has exited, reap it and try again
587 ;; If a process is running, add CODE to the sentinel
595 ; (goto-char...)'
597 sentinel))))))
600 nil)
603 "Hook run at the end of `vc-do-command'.
604 Each function is called inside the buffer in which the command was run
608 "Execute a version control command, notifying user and checking for errors.
609 Output from COMMAND goes to BUFFER, or *vc* if BUFFER is nil or the current
610 buffer (which is assumed to be properly setup) if BUFFER is t. The
611 command is considered successful if its exit status does not exceed
612 OKSTATUS (if OKSTATUS is nil, that means to ignore errors, if it is 'async,
613 that means not to wait for termination of the subprocess). FILE is
614 the name of the working file (may also be nil, to execute commands
615 that don't expect a file name). If an optional list of FLAGS is present,
616 that is inserted into the command line before the filename."
627 ;; FIXME: file-relative-name can return a bogus result because
628 ;; it doesn't look at the actual file-system to see if symlinks
629 ;; come into play.
632 ;; Add vc-path to PATH for the execution of this command.
635 path-separator
637 process-environment))
641 squeezed)))
643 ;;(set-process-sentinel proc (lambda (p msg) (delete-process p)))
658 status)))
661 "Save a bit of the text around POSN in the current buffer.
662 Used to help us find the corresponding position again later
663 if markers are destroyed or corrupted."
664 ;; A lot of this was shamelessly lifted from Sebastian Kremer's
665 ;; rcs.el mode.
672 "Return the position of CONTEXT in the current buffer, or nil if not found."
681 ;; Can't use search-backward since the match may continue
682 ;; after point.
684 ;; goto-char doesn't signal an error at
685 ;; beginning of buffer like backward-char would
687 ;; to beginning of OSTRING
691 "Return t if POSN matches CONTEXT, nil otherwise."
696 nil
700 "Return a list (POINT-CONTEXT MARK-CONTEXT REPARSE).
701 Used by `vc-restore-buffer-context' to later restore the context."
703 ;; Use mark-marker to avoid confusion in transient-mark-mode.
706 ;; Make the right thing happen in transient-mark-mode.
708 ;; We may want to reparse the compilation buffer after revert
711 ;; Construct a list; each elt is nil or a buffer
712 ;; iff that buffer is a compilation output buffer
713 ;; that contains markers into the current buffer.
718 compilation-old-error-list
719 compilation-error-list))
734 "Restore point/mark, and reparse any affected compilation buffers.
735 CONTEXT is that which `vc-buffer-context' returns."
739 ;; Reparse affected compilation buffers.
744 ;; Record the position in the compilation buffer of
745 ;; the last error next-error went to.
748 ;; Reparse the error messages as far as they were parsed before.
750 ;; Move the pointer up to find the error we were at before
751 ;; reparsing. Now next-error should properly go to the next one.
757 ;; if necessary, restore point and mark
762 mark-context
768 "Revert buffer, trying to keep point and mark where user expects them.
769 Tries to be clever in the face of changes due to expanded version control
770 key words. This is important for typeahead to work as expected.
771 ARG and NO-CONFIRM are passed on to `revert-buffer'."
775 ;; Use save-excursion here, because it may be able to restore point
776 ;; and mark properly even in cases where vc-restore-buffer-context
777 ;; would fail. However, save-excursion might also get it wrong --
778 ;; in this case, vc-restore-buffer-context gives it a second try.
780 ;; t means don't call normal-mode;
781 ;; that's to preserve various minor modes.
787 "Make sure the current buffer and its working file are in sync.
788 NOT-URGENT means it is ok to continue if the user says not to save."
797 "Has FILE changed since last checkout?"
804 unchanged))))
807 "Default check whether FILE is unchanged: diff against master version."
811 "Force a recomputation of the version control state of FILE.
812 The state is computed using the exact, and possibly expensive
813 function `vc-BACKEND-state', not the heuristic."
817 "Do The Right Thing for a given version-controlled FILE.
818 If COMMENT is specified, it will be used as an admin or checkin comment.
819 If VERBOSE is non-nil, query the user rather than using default parameters."
821 state version)
823 ;; Check relation of buffer and file, and make sure
824 ;; user knows what he's doing. First, finding the file
825 ;; will check whether the file on disk is newer.
833 ;; Now, check if we have unsaved changes.
839 ;; Do the right thing
846 ;; up-to-date
851 ;; go to a different version
858 version))))
860 ;; check the file out
863 ;; do nothing
866 ;; Abnormal: edited but read-only
868 ;; Make the file+buffer read-write. If the user really wanted to
869 ;; commit, he'll get a chance to do that next time around, anyway.
875 ;; edited
878 ;; For files with locking, if the file does not contain
879 ;; any changes, just let go of the lock, i.e. revert.
882 ;; If buffer is modified, that means the user just
883 ;; said no to saving it; in that case, don't revert,
884 ;; because the user might intend to save after
885 ;; finishing the log entry.
887 ;; DO NOT revert the file without asking the user!
900 ;; locked by somebody else
908 state))
910 ;; needs-patch
913 "%s is not up-to-date. Get latest version? "
921 ;; needs-merge
924 "%s is not up-to-date. Merge in changes now? "
929 ;; unlocked-changes
942 ;; Must clear any headers here because they wouldn't
943 ;; show that the file is locked now.
955 "Call `vc-next-action-on-file' on all the marked files.
956 Ignores FILE and REV, but passes on COMMENT."
966 nil t))
969 ;; Here's the major entry point.
971 ;;;###autoload
973 "Do the next logical checkin or checkout operation on the current file.
975 If you call this from within a VC dired buffer with no files marked,
976 it will operate on the file in the current line.
978 If you call this from within a VC dired buffer, and one or more
979 files are marked, it will accept a log message and then operate on
980 each one. The log message will be used as a comment for any register
981 or checkin operations, but ignored when doing checkouts. Attempted
982 lock steals will raise an error.
984 A prefix argument lets you specify the version number to use.
986 For RCS and SCCS files:
987 If the file is not already registered, this registers it for version
988 control.
989 If the file is registered and not locked by anyone, this checks out
990 a writable and locked file ready for editing.
991 If the file is checked out and locked by the calling user, this
992 first checks to see if the file has changed since checkout. If not,
993 it performs a revert.
994 If the file has been changed, this pops up a buffer for entry
995 of a log message; when the message has been entered, it checks in the
996 resulting changes along with the log message as change commentary. If
997 the variable `vc-keep-workfiles' is non-nil (which is its default), a
998 read-only copy of the changed file is left in place afterwards.
999 If the file is registered and locked by someone else, you are given
1000 the option to steal the lock.
1002 For CVS files:
1003 If the file is not already registered, this registers it for version
1005 If the file is added but not committed, it is committed.
1006 If your working file is changed, but the repository file is
1007 unchanged, this pops up a buffer for entry of a log message; when the
1008 message has been entered, it checks in the resulting changes along
1009 with the logmessage as change commentary. A writable file is retained.
1010 If the repository file is changed, you are asked if you want to
1011 merge in the changes into your working copy."
1026 "Enter a change comment for the marked files."
1035 ;;; These functions help the vc-next-action entry point
1037 ;;;###autoload
1039 "Register the current file into a version control system.
1040 With prefix argument SET-VERSION, allow user to specify initial version
1041 level. If COMMENT is present, use that as an initial comment.
1043 The version control system to use is found by cycling through the list
1044 `vc-handled-backends'. The first backend in that list which declares
1045 itself responsible for the file (usually because other files in that
1046 directory are already registered under that backend) will be used to
1047 register the file. If no backend declares itself responsible, the
1048 first backend that could register the file is used."
1056 ;; Watch out for new buffers of size 0: the corresponding file
1057 ;; does not exist yet, even though buffer-modified-p is nil.
1068 ;; TODO: Use backend-specific init version.
1069 vc-default-init-version)
1071 nil
1072 "Enter initial comment."
1086 "Return the name of a backend system that is responsible for FILE.
1087 The optional argument REGISTER means that a backend suitable for
1088 registration should be found.
1090 If REGISTER is nil, then if FILE is already registered, return the
1091 backend of FILE. If FILE is not registered, or a directory, then the
1092 first backend in `vc-handled-backends' that declares itself
1093 responsible for FILE is returned. If no backend declares itself
1094 responsible, return the first backend.
1096 If REGISTER is non-nil, return the first responsible backend under
1097 which FILE is not yet registered. If there is no such backend, return
1098 the first backend under which FILE is not yet registered, but could
1099 be registered."
1104 ;; First try: find a responsible backend. If this is for registration,
1105 ;; it must be a backend under which FILE is not yet registered.
1111 ;; no responsible backend
1113 ;; if this is not for registration, the first backend must do
1115 ;; for registration, we need to find a new backend that
1116 ;; could register FILE
1124 "Indicate whether BACKEND is reponsible for FILE.
1125 The default is to return nil always."
1126 nil)
1129 "Return non-nil if BACKEND could be used to register FILE.
1130 The default implementation returns t for all files."
1131 t)
1134 "If FILE is in the current buffer, either revert or unvisit it.
1135 The choice between revert (to see expanded keywords) and unvisit depends on
1136 `vc-keep-workfiles'. NOQUERY if non-nil inhibits confirmation for
1137 reverting. NOQUERY should be t *only* if it is known the only
1138 difference between the buffer and the file is due to version control
1139 rather than user editing!"
1144 ;; TODO: Adjusting view mode might no longer be necessary
1145 ;; after RMS change to files.el of 1999-08-08. Investigate
1146 ;; this when we install the new VC.
1159 "If FILE is currently visited, resynch its buffer."
1169 "Accept a comment for an operation on FILE revision REV.
1170 If COMMENT is nil, pop up a VC-log buffer, emit MSG, and set the
1171 action on close to ACTION. If COMMENT is a string and
1172 INITIAL-CONTENTS is non-nil, then COMMENT is used as the initial
1173 contents of the log entry buffer. If COMMENT is a string and
1174 INITIAL-CONTENTS is nil, do action immediately as if the user had
1175 entered COMMENT. If COMMENT is t, also do action immediately with an
1176 empty comment. Remember the file's buffer in `vc-parent-buffer'
1177 \(current one if no file). AFTER-HOOK specifies the local value
1178 for vc-log-operation-hook."
1208 "Retrieve a copy of the revision REV of FILE.
1209 If WRITABLE is non-nil, make sure the retrieved file is writable.
1210 REV defaults to the latest revision."
1218 file
1222 ;; Maybe the backend is not installed ;-(
1230 'up-to-date
1237 "Steal the lock on FILE."
1243 file-description owner)))
1246 nil nil nil nil
1257 ;; This is called when the notification has been sent.
1260 file
1267 "Check in FILE.
1268 The optional argument REV may be a string specifying the new version
1269 level (if nil increment the current level). COMMENT is a comment
1270 string; if omitted, a buffer is popped up to accept a comment. If
1271 INITIAL-CONTENTS is non-nil, then COMMENT is used as the initial contents
1272 of the log entry buffer.
1274 If `vc-keep-workfiles' is nil, FILE is deleted afterwards, provided
1275 that the version control system supports this mode of operation.
1277 Runs the normal hook `vc-checkin-hook'."
1279 file rev comment initial-contents
1280 "Enter a change comment."
1283 ;; "This log message intentionally left almost blank".
1284 ;; RCS 5.7 gripes about white-space-only comments too.
1288 file
1289 ;; Change buffers to get local value of vc-checkin-switches.
1301 "Enter last VC comment into change log file for current buffer's file.
1302 Optional arg (interactive prefix) non-nil means prompt for user name and site.
1303 Second arg is file name of change log. \
1304 If nil, uses `change-log-default-name'.
1306 May be useful as a `vc-checkin-hook' to update change logs automatically."
1310 ;; Make sure the defvar for add-log-current-defun-function has been executed
1311 ;; before binding it.
1315 ;; Don't let add-change-log-entry insert a defun name.
1317 end)
1318 ;; Call add-log to do half the work.
1320 ;; Insert the VC comment, leaving point before it.
1323 ;; It starts with an open-paren, as in "(foo): Frobbed."
1324 ;; So remove the ": " add-log inserted.
1326 ;; Canonicalize the white space between the file name and comment.
1328 ;; Indent rest of the text the same way add-log indented the first line.
1335 ;; Fill the inserted text, preserving open-parens at bol.
1340 ;; Canonicalize the white space at the end of the entry so it is
1341 ;; separated from the next entry by a single blank line.
1348 "Complete the operation implied by the current log entry."
1350 ;; Check and record the comment, if any.
1352 ;; Comment too long?
1357 ;; Record the comment in the comment ring
1363 ;; Sync parent buffer in case the user modified it while editing the comment.
1364 ;; But not if it is a vc-dired buffer.
1368 ;; save the parameters held in buffer-local variables
1376 ;; OK, do it to it
1379 log-file
1380 log-version
1381 log-entry))
1382 ;; Remove checkin window (after the checkin so that if that fails
1383 ;; we don't zap the *VC-log* buffer and the typing therein).
1387 ;; Kill buffer and delete any other dedicated windows/frames.
1392 ;; Now make sure we see the expanded headers
1399 ;; Code for access to the comment ring
1404 ;; Initialize the index on the first use of this command
1405 ;; so that the first M-p gets index 0, and the first M-n gets
1406 ;; index -1.
1409 len))
1412 "Cycle backwards through comment history."
1423 "Cycle forwards through comment history."
1428 "Search backwards through comment history for substring match."
1429 ;; Why substring rather than regexp ? -sm
1446 "Search forwards through comment history for substring match."
1451 ;; Additional entry points for examining version histories
1453 ;;;###autoload
1455 "Display diffs between file versions.
1456 Normally this compares the current file and buffer with the most recent
1457 checked in version of that file. This uses no arguments.
1458 With a prefix argument, it reads the file name to use
1459 and two version designators specifying which versions to compare."
1471 "For FILE, report diffs between two stored versions REL1 and REL2 of it.
1472 If FILE is a directory, generate diffs between versions for all registered
1473 files in or below it."
1477 "File or dir to diff: (default visited file) "
1479 default-directory buffer-file-name t)))
1481 ;; compute default versions based on the file state
1483 ;; if it's a directory, don't supply any version default
1485 nil)
1486 ;; if the file is not up-to-date, use current version as older version
1489 ;; if the file is not locked, use last and previous version as default
1494 ;; construct argument list
1500 nil nil rel1-default)
1505 nil nil rel2-default))))
1508 ;; recursive directory diff
1514 " and "
1518 ;; FIXME: this should do a single exec in CVS.
1520 default-directory
1528 ;; single file diff
1535 file
1549 nil)
1551 ;; Gnus-5.8.5 sets up an autoload for diff-mode, even if it's
1552 ;; not available. Work around that.
1558 t))
1560 ;;;###autoload
1562 "Visit version REV of the current buffer in another window.
1563 If the current buffer is named `F', the version is named `F.~REV~'.
1564 If `F.~REV~' already exists, it is used instead of being re-created."
1569 rev))
1575 ;; Header-insertion code
1577 ;;;###autoload
1579 "Insert headers in a file for use with your version control system.
1580 Headers desired are inserted at point, and are pulled from
1581 the variable `vc-BACKEND-header'."
1599 hdstrings)
1604 vc-static-header-alist))
1605 )
1606 )))))
1609 "Clear all version headers in the current buffer (or FILE).
1610 I.e. reset them to the non-expanded form."
1617 ;; save-excursion may be able to relocate point and mark
1618 ;; properly. If it fails, vc-restore-buffer-context
1619 ;; will give it a second try.
1627 ;;;###autoload
1629 "Merge changes between two versions into the current buffer's file.
1630 This asks for two versions to merge from in the minibuffer. If the
1631 first version is a branch number, then merge all changes from that
1632 branch. If the first version is empty, merge news, i.e. recent changes
1633 from the current branch.
1635 See Info node `Merging'."
1642 first-version second-version status)
1664 ;; We want to merge an entire branch. Set versions
1665 ;; accordingly, so that vc-BACKEND-merge understands us.
1667 ;; first-version must be the starting point of the branch
1689 ;;;###autoload
1691 "Invoke ediff to resolve conflicts in the current buffer.
1692 The conflicts must be marked with rcsmerge conflict markers."
1741 ;; Fire up ediff.
1745 ;; Ediff is now set up, and we are in the control buffer.
1746 ;; Do a few further adjustments and take precautions for exit.
1770 nil))))
1772 ;; The VC directory major mode. Coopt Dired for this.
1773 ;; All VC commands get mapped into logical equivalents.
1782 ;; Emacs-20 has a lousy keymap inheritance that won't work here.
1783 ;; Emacs-21's is still lousy but just better enough that it'd work. -sm
1784 ;; (set-keymap-parent vmap vc-prefix-map)
1788 map))
1791 "The major mode used in VC directory buffers.
1793 It works like Dired, but lists only files under version control, with
1794 the current VC state of each file being indicated in the place of the
1795 file's link count, owner, group and size. Subdirectories are also
1796 listed, and you may insert them into the buffer as desired, like in
1797 Dired.
1799 All Dired commands operate normally, with the exception of `v', which
1800 is redefined as the version control prefix, so that you can type
1801 `vl', `v=' etc. to invoke `vc-print-log', `vc-diff', and the like on
1802 the file named in the current Dired buffer line. `vv' invokes
1803 `vc-next-action' on this file, or on all files currently marked.
1804 There is a special command, `*l', to mark all files currently locked."
1805 ;; define-derived-mode does it for us in Emacs-21, but not in Emacs-20.
1806 ;; We do it here because dired might not be loaded yet
1807 ;; when vc-dired-mode-map is initialized.
1811 ;; The following is slightly modified from dired.el,
1812 ;; because file lines look a bit different in vc-dired-mode.
1816 ;; In some locales, month abbreviations are as short as 2 letters,
1817 ;; and they can be padded on the right with spaces.
1819 ;; Recognize any non-ASCII character.
1820 ;; The purpose is to match a Kanji character.
1822 ;; (k "[^\x00-\x7f\x80-\xff]")
1831 ;; the .* below ensures that we find the last match on a line
1834 vc-dired-switches
1836 vc-dired-switches))
1841 "Toggle terse display in VC Dired."
1844 nil
1851 "Mark all files currently locked."
1871 "Reformat a directory-listing line.
1872 Replace various columns with version control information.
1873 This code, like dired, assumes UNIX -l format."
1883 limit t)
1886 limit t)
1889 limit t))
1896 "Reformat the listing according to version control.
1897 Called by dired after any portion of a vc-dired buffer has been read in."
1903 ;; subdir header line
1905 ;; if the backend supports it, get the state
1906 ;; of all files in this directory at once
1911 ;; erase (but don't remove) the "total" line
1915 ;; file line
1918 ;; subdir
1922 vc-directory-exclusion-list)
1928 ;; Don't show directories in terse mode. Don't use
1929 ;; dired-kill-line to remove it, because in recursive listings,
1930 ;; that would remove the directory contents as well.
1938 ;; ordinary file
1946 ;; any other line
1957 "Remove empty subdirs."
1968 ;; We cannot remove the top level directory.
1969 ;; Just make it look a little nicer.
1977 "Return a list of all vc-dired buffers that currently display DIR."
1979 ;; Check whether dired is loaded.
1986 result))
1989 "Update the entries for FILE in any VC Dired buffers that list it."
1995 ;; bind vc-dired-terse-mode to nil so that
1996 ;; files won't vanish when they are checked in
1999 buffers))))
2001 ;;;###autoload
2003 "Create a buffer in VC Dired Mode for directory DIR.
2005 See Info node `VC Dired Mode'.
2007 With prefix arg READ-SWITCHES, specify a value to override
2008 `dired-listing-switches' when generating the listing."
2015 vc-dired-switches)))
2020 vc-dired-switches
2024 ;; Named-configuration entry points
2027 "Scan the tree below DIR, looking for non-uptodate files.
2028 If any file is not up-to-date, return the name of the first such file.
2029 \(This means, neither snapshot creation nor retrieval is allowed.\)
2030 If one or more of the files are currently visited, return `visited'.
2031 Otherwise, return nil."
2035 dir
2039 status)))
2041 ;;;###autoload
2043 "Descending recursively from DIR, make a snapshot called NAME.
2044 For each registered file, the version level of its latest version
2045 becomes part of the named configuration. If the prefix argument
2046 BRANCHP is given, the snapshot is made as a new branch and the files
2047 are checked out in that new branch."
2051 current-prefix-arg))
2065 dir
2069 ;;;###autoload
2071 "Descending recursively from DIR, retrieve the snapshot called NAME.
2072 If NAME is empty, it refers to the latest versions.
2073 If locking is used for the files in DIR, then there must not be any
2074 locked files at or below DIR (but if NAME is empty, locked files are
2075 allowed and simply skipped)."
2093 dir
2104 dir
2110 ;; Miscellaneous other entry points
2112 ;;;###autoload
2114 "List the change log of the current buffer in a window."
2133 ;; move point to the log entry for the current version
2138 'show-log-entry
2142 "Return a string with all log entries that were made under BACKEND for FILE."
2150 "Remove all non-comment information from log output.
2151 This default implementation works for RCS logs; backends should override
2152 it if their logs are not in RCS format."
2169 ;;;###autoload
2171 "Revert the current buffer's file back to the version it was based on.
2172 This asks for confirmation if the buffer contents are not identical
2173 to that version. This function does not automatically pick up newer
2178 ;; This operation should always ask for confirmation.
2181 status)
2183 ;; vc-diff selects the new window, which is not what we want:
2184 ;; if the new window is on another frame, that'd require the user
2185 ;; moving her mouse to answer the yes-or-no-p question.
2199 ;; Do the reverting
2205 "If version backups should be used for FILE, and there exists
2206 such a backup for REV or the current workfile version of file,
2207 return the name of it; otherwise return nil."
2211 backup-file))))
2214 "Revert FILE back to the version it was based on."
2216 file
2226 ;;;###autoload
2228 "Get rid of most recently checked in version of this file.
2229 A prefix argument NOREVERT means do not revert the buffer afterwards."
2242 (error (substitute-command-keys "File is not up to date; use \\[vc-revert-buffer] to discard changes"))))
2250 file
2254 0
2263 ;; inhibit backup for this buffer
2274 ;;;autoload
2276 "Make BACKEND the current version control system for FILE.
2277 FILE must already be registered in BACKEND. The change is not
2278 permanent, only for the current session. This function only changes
2279 VC's perspective on FILE, it does not register or unregister it.
2280 By default, this command cycles through the registered backends.
2281 To get a prompt, use a prefix argument."
2284 buffer-file-name
2287 ;; Find the registered backends.
2291 ;; Find the next backend.
2307 ;; Force recomputation of the state
2313 ;;;autoload
2315 "Transfer FILE to another version control system NEW-BACKEND.
2316 If NEW-BACKEND has a higher precedence than FILE's current backend
2317 \(i.e. it comes earlier in `vc-handled-backends'), then register FILE in
2318 NEW-BACKEND, using the version number from the current backend as the
2319 base level. If NEW-BACKEND has a lower precedence than the current
2320 backend, then commit all changes that were made under the current
2321 backend to NEW-BACKEND, and unregister FILE from the current backend.
2322 \(If FILE is not yet registered under NEW-BACKEND, register it.)"
2328 ;; move if new-backend comes later in vc-handled-backends
2336 ;; `registered' might have switched under us.
2341 ;; Go back to the base unmodified file.
2346 ;; If we have a local copy of the unmodified file, handle that
2347 ;; here and not in vc-revert-file because we don't want to
2348 ;; delete that copy -- it is still useful for OLD-BACKEND.
2371 "Default implementation of `vc-unregister', signals an error."
2375 "Let BACKEND receive FILE from another version control system."
2379 "Rename OLDMASTER to be the master file for NEWFILE based on TEMPLATES."
2384 ;; List of potential master files for `newfile'
2387 templates)))
2392 oldmaster
2394 ;; If possible, keep the master file in the same directory.
2397 dir))
2399 masters)
2400 ;; If not, just use the first possible place.
2406 masters)
2409 ;;;###autoload
2411 "Rename file OLD to NEW, and rename its master file likewise."
2413 ;; There are several ways of renaming files under CVS 1.3, but they all
2414 ;; have serious disadvantages. See the FAQ (available from think.com in
2415 ;; pub/cvs/). I'd rather send the user an error, than do something he might
2416 ;; consider to be wrong. When the famous, long-awaited rename database is
2417 ;; implemented things might change for the better. This is unlikely to occur
2418 ;; until CVS 2.0 is released. --ceder 1994-01-23 21:27:51
2433 ;; Move the actual file (unless the backend did it already)
2436 ;; ?? Renaming a file might change its contents due to keyword expansion.
2437 ;; We should really check out a new copy if the old copy was precisely equal
2438 ;; to some checked in version. However, testing for this is tricky....
2447 ;; Only defined in very recent Emacsen
2450 ;;;###autoload
2452 "Find change log file and add entries from recent version control logs.
2453 Normally, find log entries for all registered files in the default
2454 directory.
2456 With prefix arg of \\[universal-argument], only find log entries for the current buffer's file.
2458 With any numeric prefix arg, find log entries for all currently visited
2459 files that are under version control. This puts all the entries in the
2460 log for the default directory, which may not be appropriate.
2462 From a program, any ARGS are assumed to be filenames for which
2463 log entries should be gathered."
2470 file)
2476 files))
2478 ;; Don't supply any filenames to backend; this means
2479 ;; it should find all relevant files relative to
2480 ;; the default-directory.
2481 nil)))
2486 "Default implementation of update-changelog.
2487 Uses `rcs2log' which only works for RCS and CVS."
2488 ;; FIXME: We (c|sh)ould add support for cvs2cl
2491 ;; Presumably not portable to non-Unixy systems, along with rcs2log:
2496 temporary-file-directory))))
2502 user-mail-address)))
2516 exec-directory)
2518 "-c" changelog
2526 f
2528 files)))
2529 "done"
2538 ;;; Annotate functionality
2540 ;; Declare globally instead of additional parameter to
2541 ;; temp-buffer-show-function (not possible to pass more than one
2542 ;; parameter).
2548 Return NIL if no match made. Associations are made based on
2549 `vc-annotate-buffers'."
2553 "Major mode for buffers displaying output from the `annotate' command.
2555 You can use the mode-specific menu to alter the time-span of the used
2556 colors. See variable `vc-annotate-menu-elements' for customizing the
2557 menu items."
2561 "Use the default color spectrum for VC Annotate mode."
2565 nil
2570 "Add the menu 'Annotate' to the menu bar in VC-Annotate mode."
2575 '("Default" . vc-annotate-display-default))
2576 (let ((menu-elements vc-annotate-menu-elements))
2577 (while menu-elements
2578 (let* ((element (car menu-elements))
2579 (days (round (* element
2580 (vc-annotate-car-last-cons vc-annotate-color-map)
2581 0.7585))))
2582 (setq menu-elements (cdr menu-elements))
2583 (define-key vc-annotate-mode-menu
2584 (vector days)
2585 (cons (format "Span %d days"
2586 days)
2587 `(lambda ()
2588 ,(format "Use colors spanning %d days" days)
2589 (interactive)
2590 (message "Redisplaying annotation...")
2591 (vc-annotate-display
2592 (get-buffer (buffer-name))
2593 (vc-annotate-time-span vc-annotate-color-map ,element)
2594 (vc-annotate-get-backend (current-buffer)))
2595 (message "Redisplaying annotation...done"))))))))
2598 ;;;; (defun vc-BACKEND-annotate-command (file buffer) ...)
2599 ;;;; Execute "annotate" on FILE by using `call-process' and insert
2600 ;;;; the contents in BUFFER.
2602 ;;;###autoload
2603 (defun vc-annotate (ratio)
2606 are displayed in red, old in blue. A prefix argument specifies a
2607 factor for stretching the time scale.
2609 `vc-annotate-menu-elements' customizes the menu elements of the
2610 mode-specific menu. `vc-annotate-color-map' and
2611 `vc-annotate-very-old-color' defines the mapping of time to
2612 colors. `vc-annotate-background' specifies the background color."
2613 (interactive "p")
2614 (vc-ensure-vc-buffer)
2615 (message "Annotating...")
2616 (let ((temp-buffer-name (concat "*Annotate " (buffer-name) "*"))
2617 (temp-buffer-show-function 'vc-annotate-display)
2618 (vc-annotate-ratio ratio)
2619 (vc-annotate-backend (vc-backend (buffer-file-name))))
2620 (if (not (vc-find-backend-function vc-annotate-backend 'annotate-command))
2621 (error "Sorry, annotating is not implemented for %s"
2622 vc-annotate-backend))
2623 (with-output-to-temp-buffer temp-buffer-name
2624 (vc-call-backend vc-annotate-backend 'annotate-command
2625 (file-name-nondirectory (buffer-file-name))
2626 (get-buffer temp-buffer-name)))
2627 ;; Don't use the temp-buffer-name until the buffer is created
2628 ;; (only after `with-output-to-temp-buffer'.)
2629 (setq vc-annotate-buffers
2630 (append vc-annotate-buffers
2631 (list (cons (get-buffer temp-buffer-name) vc-annotate-backend)))))
2632 (message "Annotating... done"))
2635 (defun vc-annotate-car-last-cons (a-list)
2636 "Return car of last cons in association list A-LIST."
2637 (if (not (eq nil (cdr a-list)))
2638 (vc-annotate-car-last-cons (cdr a-list))
2639 (car (car a-list))))
2641 (defun vc-annotate-time-span (a-list span &optional quantize)
2642 "Apply factor SPAN to the time-span of association list A-LIST.
2643 Return the new alist.
2644 Optionally quantize to the factor of QUANTIZE."
2645 ;; Apply span to each car of every cons
2646 (if (not (eq nil a-list))
2647 (append (list (cons (* (car (car a-list)) span)
2648 (cdr (car a-list))))
2649 (vc-annotate-time-span (nthcdr (or quantize ; optional
2650 1) ; Default to cdr
2651 a-list) span quantize))))
2653 (defun vc-annotate-compcar (threshold a-list)
2654 "Test successive cons cells of association list A-LIST against THRESHOLD.
2655 Return the first cons cell which car is not less than THRESHOLD,
2656 nil otherwise"
2657 (let ((i 1)
2658 (tmp-cons (car a-list)))
2659 (while (and tmp-cons (< (car tmp-cons) threshold))
2660 (setq tmp-cons (car (nthcdr i a-list)))
2661 (setq i (+ i 1)))
2662 tmp-cons)) ; Return the appropriate value
2665 ;;;; (defun vc-BACKEND-annotate-difference (point) ...)
2666 ;;;;
2667 ;;;; Return the difference between the age of the line at point and
2668 ;;;; the current time. Return NIL if there is no more comparison to
2669 ;;;; be made in the buffer. Return value as defined for
2670 ;;;; `current-time'. You can safely assume that point is placed at
2671 ;;;; the beginning of each line, starting at `point-min'. The buffer
2672 ;;;; that point is placed in is the Annotate output, as defined by
2673 ;;;; the relevant backend.
2675 (defun vc-annotate-display (buffer &optional color-map backend)
2676 "Do the VC-Annotate display in BUFFER using COLOR-MAP.
2677 The original annotating file is supposed to be handled by BACKEND.
2678 If BACKEND is NIL, variable VC-ANNOTATE-BACKEND is used instead.
2679 This function is destructive on VC-ANNOTATE-BACKEND when BACKEND is non-nil."
2681 ;; Handle the case of the global variable vc-annotate-ratio being
2682 ;; set. This variable is used to pass information from function
2683 ;; vc-annotate since it is not possible to use another parameter
2684 ;; (see temp-buffer-show-function).
2685 (if (and (not color-map) vc-annotate-ratio)
2686 ;; This will only be true if called from vc-annotate with ratio
2687 ;; being non-nil.
2688 (setq color-map (vc-annotate-time-span vc-annotate-color-map
2689 vc-annotate-ratio)))
2690 (set-buffer buffer)
2691 (display-buffer buffer)
2692 (if (not vc-annotate-mode) ; Turn on vc-annotate-mode if not done
2693 (vc-annotate-mode))
2694 (goto-char (point-min)) ; Position at the top of the buffer.
2695 ;; Delete old overlays
2696 (mapcar
2697 (lambda (overlay)
2698 (if (overlay-get overlay 'vc-annotation)
2699 (delete-overlay overlay)))
2700 (overlays-in (point-min) (point-max)))
2701 (goto-char (point-min)) ; Position at the top of the buffer.
2703 (if backend (setq vc-annotate-backend backend)) ; Destructive on `vc-annotate-backend'
2705 (let ((difference (vc-call-backend vc-annotate-backend 'annotate-difference (point))))
2706 (while difference
2707 (let*
2708 ((color (or (vc-annotate-compcar
2709 difference (or color-map vc-annotate-color-map))
2710 (cons nil vc-annotate-very-old-color)))
2711 ;; substring from index 1 to remove any leading `#' in the name
2712 (face-name (concat "vc-annotate-face-" (substring (cdr color) 1)))
2713 ;; Make the face if not done.
2714 (face (or (intern-soft face-name)
2715 (let ((tmp-face (make-face (intern face-name))))
2716 (set-face-foreground tmp-face (cdr color))
2717 (if vc-annotate-background
2718 (set-face-background tmp-face vc-annotate-background))
2719 tmp-face))) ; Return the face
2720 (point (point))
2721 overlay)
2722 (forward-line 1)
2723 (setq overlay (make-overlay point (point)))
2724 (overlay-put overlay 'face face)
2725 (overlay-put overlay 'vc-annotation t))
2726 (setq difference (vc-call-backend vc-annotate-backend 'annotate-difference (point))))))
2728 \f
2729 ;; Collect back-end-dependent stuff here
2731 (defalias 'vc-default-logentry-check 'ignore)
2733 (defun vc-check-headers ()
2734 "Check if the current file has any headers in it."
2735 (interactive)
2736 (vc-call-backend (vc-backend buffer-file-name) 'check-headers))
2738 ;; Back-end-dependent stuff ends here.
2740 ;; Set up key bindings for use while editing log messages
2742 (define-derived-mode vc-log-mode text-mode "VC-Log"
2743 "Major mode for editing VC log entries.
2744 These bindings are added to the global keymap when you enter this mode:
2758 While you are entering a change log message for a version, the following
2759 additional bindings will be in effect.
2763 Whenever you do a checkin, your log comment is added to a ring of
2764 saved comments. These can be recalled as follows:
2771 Entry to the change-log submode calls the value of `text-mode-hook', then
2772 the value of `vc-log-mode-hook'.
2774 Global user options:
2775 `vc-initial-comment' If non-nil, require user to enter a change
2776 comment upon first checkin of the file.
2778 `vc-keep-workfiles' Non-nil value prevents workfiles from being
2779 deleted when changes are checked in
2781 `vc-suppress-confirm' Suppresses some confirmation prompts,
2782 notably for reversions.
2784 vc-BACKEND-header Which keywords to insert when adding headers
2787 RCS and CVS.
2789 `vc-static-header-alist' By default, version headers inserted in C files
2790 get stuffed in a static string area so that
2791 ident(RCS/CVS) or what(SCCS) can see them in
2792 the compiled object code. You can override
2793 this by setting this variable to nil, or change
2794 the header template by changing it.
2796 `vc-command-messages' if non-nil, display run messages from the
2797 actual version-control utilities (this is
2798 intended primarily for people hacking vc
2799 itself)."
2800 (make-local-variable 'vc-comment-ring-index))
2802 (defun vc-log-edit (file)
2803 "Set up `log-edit' for use with VC on FILE.
2804 If `log-edit' is not available, resort to `vc-log-mode'."
2805 (setq default-directory
2806 (if file (file-name-directory file)
2807 (with-current-buffer vc-parent-buffer default-directory)))
2808 (if (fboundp 'log-edit)
2809 (log-edit 'vc-finish-logentry nil
2810 (if file `(lambda () ',(list (file-name-nondirectory file)))
2811 ;; If FILE is nil, we were called from vc-dired.
2812 (lambda ()
2813 (with-current-buffer vc-parent-buffer
2814 (dired-get-marked-files t)))))
2815 (vc-log-mode))
2816 (set (make-local-variable 'vc-log-file) file)
2817 (make-local-variable 'vc-log-version)
2818 (set-buffer-modified-p nil)
2819 (setq buffer-file-name nil))
2821 ;;; These things should probably be generally available
2823 (defun vc-file-tree-walk (dirname func &rest args)
2824 "Walk recursively through DIRNAME.
2825 Invoke FUNC f ARGS on each VC-managed file f underneath it."
2826 (vc-file-tree-walk-internal (expand-file-name dirname) func args)
2827 (message "Traversing directory %s...done" dirname))
2829 (defun vc-file-tree-walk-internal (file func args)
2830 (if (not (file-directory-p file))
2831 (if (vc-backend file) (apply func file args))
2832 (message "Traversing directory %s..." (abbreviate-file-name file))
2833 (let ((dir (file-name-as-directory file)))
2834 (mapcar
2835 (lambda (f) (or
2836 (string-equal f ".")
2837 (string-equal f "..")
2838 (member f vc-directory-exclusion-list)
2839 (let ((dirf (expand-file-name f dir)))
2840 (or
2841 (file-symlink-p dirf);; Avoid possible loops
2842 (vc-file-tree-walk-internal dirf func args)))))
2843 (directory-files dir)))))
2845 (provide 'vc)
2847 ;;; DEVELOPER'S NOTES ON CONCURRENCY PROBLEMS IN THIS CODE
2848 ;;;
2849 ;;; These may be useful to anyone who has to debug or extend the package.
2850 ;;; (Note that this information corresponds to versions 5.x. Some of it
2851 ;;; might have been invalidated by the additions to support branching
2852 ;;; and RCS keyword lookup. AS, 1995/03/24)
2853 ;;;
2854 ;;; A fundamental problem in VC is that there are time windows between
2855 ;;; vc-next-action's computations of the file's version-control state and
2856 ;;; the actions that change it. This is a window open to lossage in a
2857 ;;; multi-user environment; someone else could nip in and change the state
2858 ;;; of the master during it.
2859 ;;;
2860 ;;; The performance problem is that rlog/prs calls are very expensive; we want
2861 ;;; to avoid them as much as possible.
2862 ;;;
2863 ;;; ANALYSIS:
2864 ;;;
2865 ;;; The performance problem, it turns out, simplifies in practice to the
2866 ;;; problem of making vc-state fast. The two other functions that call
2867 ;;; prs/rlog will not be so commonly used that the slowdown is a problem; one
2868 ;;; makes snapshots, the other deletes the calling user's last change in the
2869 ;;; master.
2870 ;;;
2871 ;;; The race condition implies that we have to either (a) lock the master
2872 ;;; during the entire execution of vc-next-action, or (b) detect and
2873 ;;; recover from errors resulting from dispatch on an out-of-date state.
2874 ;;;
2875 ;;; Alternative (a) appears to be infeasible. The problem is that we can't
2876 ;;; guarantee that the lock will ever be removed. Suppose a user starts a
2877 ;;; checkin, the change message buffer pops up, and the user, having wandered
2878 ;;; off to do something else, simply forgets about it?
2879 ;;;
2880 ;;; Alternative (b), on the other hand, works well with a cheap way to speed up
2881 ;;; vc-state. Usually, if a file is registered, we can read its locked/
2882 ;;; unlocked state and its current owner from its permissions.
2883 ;;;
2884 ;;; This shortcut will fail if someone has manually changed the workfile's
2885 ;;; permissions; also if developers are munging the workfile in several
2886 ;;; directories, with symlinks to a master (in this latter case, the
2887 ;;; permissions shortcut will fail to detect a lock asserted from another
2888 ;;; directory).
2889 ;;;
2890 ;;; Note that these cases correspond exactly to the errors which could happen
2891 ;;; because of a competing checkin/checkout race in between two instances of
2892 ;;; vc-next-action.
2893 ;;;
2894 ;;; For VC's purposes, a workfile/master pair may have the following states:
2895 ;;;
2896 ;;; A. Unregistered. There is a workfile, there is no master.
2897 ;;;
2898 ;;; B. Registered and not locked by anyone.
2899 ;;;
2900 ;;; C. Locked by calling user and unchanged.
2901 ;;;
2902 ;;; D. Locked by the calling user and changed.
2903 ;;;
2904 ;;; E. Locked by someone other than the calling user.
2905 ;;;
2906 ;;; This makes for 25 states and 20 error conditions. Here's the matrix:
2907 ;;;
2908 ;;; VC's idea of state
2909 ;;; |
2910 ;;; V Actual state RCS action SCCS action Effect
2911 ;;; A B C D E
2912 ;;; A . 1 2 3 4 ci -u -t- admin -fb -i<file> initial admin
2913 ;;; B 5 . 6 7 8 co -l get -e checkout
2914 ;;; C 9 10 . 11 12 co -u unget; get revert
2915 ;;; D 13 14 15 . 16 ci -u -m<comment> delta -y<comment>; get checkin
2916 ;;; E 17 18 19 20 . rcs -u -M -l unget -n ; get -g steal lock
2917 ;;;
2918 ;;; All commands take the master file name as a last argument (not shown).
2919 ;;;
2920 ;;; In the discussion below, a "self-race" is a pathological situation in
2921 ;;; which VC operations are being attempted simultaneously by two or more
2922 ;;; Emacsen running under the same username.
2923 ;;;
2924 ;;; The vc-next-action code has the following windows:
2925 ;;;
2926 ;;; Window P:
2927 ;;; Between the check for existence of a master file and the call to
2928 ;;; admin/checkin in vc-buffer-admin (apparent state A). This window may
2929 ;;; never close if the initial-comment feature is on.
2930 ;;;
2931 ;;; Window Q:
2932 ;;; Between the call to vc-workfile-unchanged-p in and the immediately
2933 ;;; following revert (apparent state C).
2934 ;;;
2935 ;;; Window R:
2936 ;;; Between the call to vc-workfile-unchanged-p in and the following
2937 ;;; checkin (apparent state D). This window may never close.
2938 ;;;
2939 ;;; Window S:
2940 ;;; Between the unlock and the immediately following checkout during a
2941 ;;; revert operation (apparent state C). Included in window Q.
2942 ;;;
2943 ;;; Window T:
2944 ;;; Between vc-state and the following checkout (apparent state B).
2945 ;;;
2946 ;;; Window U:
2947 ;;; Between vc-state and the following revert (apparent state C).
2948 ;;; Includes windows Q and S.
2949 ;;;
2950 ;;; Window V:
2951 ;;; Between vc-state and the following checkin (apparent state
2952 ;;; D). This window may never be closed if the user fails to complete the
2953 ;;; checkin message. Includes window R.
2954 ;;;
2955 ;;; Window W:
2956 ;;; Between vc-state and the following steal-lock (apparent
2957 ;;; state E). This window may never close if the user fails to complete
2958 ;;; the steal-lock message. Includes window X.
2959 ;;;
2960 ;;; Window X:
2961 ;;; Between the unlock and the immediately following re-lock during a
2962 ;;; steal-lock operation (apparent state E). This window may never close
2963 ;;; if the user fails to complete the steal-lock message.
2964 ;;;
2965 ;;; Errors:
2966 ;;;
2967 ;;; Apparent state A ---
2968 ;;;
2969 ;;; 1. File looked unregistered but is actually registered and not locked.
2970 ;;;
2971 ;;; Potential cause: someone else's admin during window P, with
2972 ;;; caller's admin happening before their checkout.
2973 ;;;
2974 ;;; RCS: Prior to version 5.6.4, ci fails with message
2975 ;;; "no lock set by <user>". From 5.6.4 onwards, VC uses the new
2976 ;;; ci -i option and the message is "<file>,v: already exists".
2977 ;;; SCCS: admin will fail with error (ad19).
2978 ;;;
2979 ;;; We can let these errors be passed up to the user.
2980 ;;;
2981 ;;; 2. File looked unregistered but is actually locked by caller, unchanged.
2982 ;;;
2983 ;;; Potential cause: self-race during window P.
2984 ;;;
2985 ;;; RCS: Prior to version 5.6.4, reverts the file to the last saved
2986 ;;; version and unlocks it. From 5.6.4 onwards, VC uses the new
2987 ;;; ci -i option, failing with message "<file>,v: already exists".
2988 ;;; SCCS: will fail with error (ad19).
2989 ;;;
2990 ;;; Either of these consequences is acceptable.
2991 ;;;
2992 ;;; 3. File looked unregistered but is actually locked by caller, changed.
2993 ;;;
2994 ;;; Potential cause: self-race during window P.
2995 ;;;
2996 ;;; RCS: Prior to version 5.6.4, VC registers the caller's workfile as
2997 ;;; a delta with a null change comment (the -t- switch will be
2998 ;;; ignored). From 5.6.4 onwards, VC uses the new ci -i option,
2999 ;;; failing with message "<file>,v: already exists".
3000 ;;; SCCS: will fail with error (ad19).
3001 ;;;
3002 ;;; 4. File looked unregistered but is locked by someone else.
3003 ;;;
3004 ;;; Potential cause: someone else's admin during window P, with
3005 ;;; caller's admin happening *after* their checkout.
3006 ;;;
3007 ;;; RCS: Prior to version 5.6.4, ci fails with a
3008 ;;; "no lock set by <user>" message. From 5.6.4 onwards,
3009 ;;; VC uses the new ci -i option, failing with message
3010 ;;; "<file>,v: already exists".
3011 ;;; SCCS: will fail with error (ad19).
3012 ;;;
3013 ;;; We can let these errors be passed up to the user.
3014 ;;;
3015 ;;; Apparent state B ---
3016 ;;;
3017 ;;; 5. File looked registered and not locked, but is actually unregistered.
3018 ;;;
3019 ;;; Potential cause: master file got nuked during window P.
3020 ;;;
3021 ;;; RCS: will fail with "RCS/<file>: No such file or directory"
3022 ;;; SCCS: will fail with error ut4.
3023 ;;;
3024 ;;; We can let these errors be passed up to the user.
3025 ;;;
3026 ;;; 6. File looked registered and not locked, but is actually locked by the
3027 ;;; calling user and unchanged.
3028 ;;;
3029 ;;; Potential cause: self-race during window T.
3030 ;;;
3031 ;;; RCS: in the same directory as the previous workfile, co -l will fail
3032 ;;; with "co error: writable foo exists; checkout aborted". In any other
3033 ;;; directory, checkout will succeed.
3034 ;;; SCCS: will fail with ge17.
3035 ;;;
3036 ;;; Either of these consequences is acceptable.
3037 ;;;
3038 ;;; 7. File looked registered and not locked, but is actually locked by the
3039 ;;; calling user and changed.
3040 ;;;
3041 ;;; As case 6.
3042 ;;;
3043 ;;; 8. File looked registered and not locked, but is actually locked by another
3044 ;;; user.
3045 ;;;
3046 ;;; Potential cause: someone else checks it out during window T.
3047 ;;;
3048 ;;; RCS: co error: revision 1.3 already locked by <user>
3049 ;;; SCCS: fails with ge4 (in directory) or ut7 (outside it).
3050 ;;;
3051 ;;; We can let these errors be passed up to the user.
3052 ;;;
3053 ;;; Apparent state C ---
3054 ;;;
3055 ;;; 9. File looks locked by calling user and unchanged, but is unregistered.
3056 ;;;
3057 ;;; As case 5.
3058 ;;;
3059 ;;; 10. File looks locked by calling user and unchanged, but is actually not
3060 ;;; locked.
3061 ;;;
3062 ;;; Potential cause: a self-race in window U, or by the revert's
3063 ;;; landing during window X of some other user's steal-lock or window S
3064 ;;; of another user's revert.
3065 ;;;
3066 ;;; RCS: succeeds, refreshing the file from the identical version in
3067 ;;; the master.
3068 ;;; SCCS: fails with error ut4 (p file nonexistent).
3069 ;;;
3070 ;;; Either of these consequences is acceptable.
3071 ;;;
3072 ;;; 11. File is locked by calling user. It looks unchanged, but is actually
3073 ;;; changed.
3074 ;;;
3075 ;;; Potential cause: the file would have to be touched by a self-race
3076 ;;; during window Q.
3077 ;;;
3078 ;;; The revert will succeed, removing whatever changes came with
3079 ;;; the touch. It is theoretically possible that work could be lost.
3080 ;;;
3081 ;;; 12. File looks like it's locked by the calling user and unchanged, but
3082 ;;; it's actually locked by someone else.
3083 ;;;
3084 ;;; Potential cause: a steal-lock in window V.
3085 ;;;
3086 ;;; RCS: co error: revision <rev> locked by <user>; use co -r or rcs -u
3087 ;;; SCCS: fails with error un2
3088 ;;;
3089 ;;; We can pass these errors up to the user.
3090 ;;;
3091 ;;; Apparent state D ---
3092 ;;;
3093 ;;; 13. File looks like it's locked by the calling user and changed, but it's
3094 ;;; actually unregistered.
3095 ;;;
3096 ;;; Potential cause: master file got nuked during window P.
3097 ;;;
3098 ;;; RCS: Prior to version 5.6.4, checks in the user's version as an
3099 ;;; initial delta. From 5.6.4 onwards, VC uses the new ci -j
3100 ;;; option, failing with message "no such file or directory".
3101 ;;; SCCS: will fail with error ut4.
3102 ;;;
3103 ;;; This case is kind of nasty. Under RCS prior to version 5.6.4,
3104 ;;; VC may fail to detect the loss of previous version information.
3105 ;;;
3106 ;;; 14. File looks like it's locked by the calling user and changed, but it's
3107 ;;; actually unlocked.
3108 ;;;
3109 ;;; Potential cause: self-race in window V, or the checkin happening
3110 ;;; during the window X of someone else's steal-lock or window S of
3111 ;;; someone else's revert.
3112 ;;;
3113 ;;; RCS: ci will fail with "no lock set by <user>".
3114 ;;; SCCS: delta will fail with error ut4.
3115 ;;;
3116 ;;; 15. File looks like it's locked by the calling user and changed, but it's
3117 ;;; actually locked by the calling user and unchanged.
3118 ;;;
3119 ;;; Potential cause: another self-race --- a whole checkin/checkout
3120 ;;; sequence by the calling user would have to land in window R.
3121 ;;;
3122 ;;; SCCS: checks in a redundant delta and leaves the file unlocked as usual.
3123 ;;; RCS: reverts to the file state as of the second user's checkin, leaving
3124 ;;; the file unlocked.
3125 ;;;
3126 ;;; It is theoretically possible that work could be lost under RCS.
3127 ;;;
3128 ;;; 16. File looks like it's locked by the calling user and changed, but it's
3129 ;;; actually locked by a different user.
3130 ;;;
3131 ;;; RCS: ci error: no lock set by <user>
3132 ;;; SCCS: unget will fail with error un2
3133 ;;;
3134 ;;; We can pass these errors up to the user.
3135 ;;;
3136 ;;; Apparent state E ---
3137 ;;;
3138 ;;; 17. File looks like it's locked by some other user, but it's actually
3139 ;;; unregistered.
3140 ;;;
3141 ;;; As case 13.
3142 ;;;
3143 ;;; 18. File looks like it's locked by some other user, but it's actually
3144 ;;; unlocked.
3145 ;;;
3146 ;;; Potential cause: someone released a lock during window W.
3147 ;;;
3148 ;;; RCS: The calling user will get the lock on the file.
3149 ;;; SCCS: unget -n will fail with cm4.
3150 ;;;
3151 ;;; Either of these consequences will be OK.
3152 ;;;
3153 ;;; 19. File looks like it's locked by some other user, but it's actually
3154 ;;; locked by the calling user and unchanged.
3155 ;;;
3156 ;;; Potential cause: the other user relinquishing a lock followed by
3157 ;;; a self-race, both in window W.
3158 ;;;
3159 ;;; Under both RCS and SCCS, both unlock and lock will succeed, making
3160 ;;; the sequence a no-op.
3161 ;;;
3162 ;;; 20. File looks like it's locked by some other user, but it's actually
3163 ;;; locked by the calling user and changed.
3164 ;;;
3165 ;;; As case 19.
3166 ;;;
3167 ;;; PROBLEM CASES:
3168 ;;;
3169 ;;; In order of decreasing severity:
3170 ;;;
3171 ;;; Cases 11 and 15 are the only ones that potentially lose work.
3172 ;;; They would require a self-race for this to happen.
3173 ;;;
3174 ;;; Case 13 in RCS loses information about previous deltas, retaining
3175 ;;; only the information in the current workfile. This can only happen
3176 ;;; if the master file gets nuked in window P.
3177 ;;;
3178 ;;; Case 3 in RCS and case 15 under SCCS insert a redundant delta with
3179 ;;; no change comment in the master. This would require a self-race in
3180 ;;; window P or R respectively.
3181 ;;;
3182 ;;; Cases 2, 10, 19 and 20 do extra work, but make no changes.
3183 ;;;
3184 ;;; Unfortunately, it appears to me that no recovery is possible in these
3185 ;;; cases. They don't yield error messages, so there's no way to tell that
3186 ;;; a race condition has occurred.
3187 ;;;
3188 ;;; All other cases don't change either the workfile or the master, and
3189 ;;; trigger command errors which the user will see.
3190 ;;;
3191 ;;; Thus, there is no explicit recovery code.
3193 ;;; vc.el ends here