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lisp/uniquify.el

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+;;; uniquify.el --- unique buffer names dependent on pathname
+
+;; Copyright (c) 1989, 1995 Free Software Foundation, Inc.
+
+;; Author: Dick King <king@reasoning.com>
+;; Maintainer: Michael Ernst <mernst@theory.lcs.mit.edu>
+;; Created: 15 May 86
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+;;; Commentary:
+
+;; Emacs's standard method for making buffer names unique adds <2>, <3>,
+;; etc. to the end of (all but one of) the buffers.  This file replaces
+;; that behavior, for buffers visiting files and dired buffers, with a
+;; uniquification that adds parts of the pathname until the buffer names
+;; are unique.  For instance, buffers visiting /u/mernst/tmp/Makefile and
+;; /usr/projects/zaphod/Makefile would be named Makefile|tmp and
+;; Makefile|zaphod, respectively (instead of Makefile and Makefile<2>).
+;; Other buffer name styles are also available.
+
+;; To use this file, just load it.
+;; To disable it after loading, set variable uniquify-buffer-name-style to nil.
+;; For other options, see "User-visible variables", below.
+
+;; uniquify.el works under Emacs, XEmacs, and InfoDock.
+
+;; Doesn't correctly handle buffer names created by M-x write-file in Emacs 18.
+
+;;; Change Log:
+
+;; Originally by Dick King <king@reasoning.com> 15 May 86
+;; Converted for Emacs 18 by Stephen Gildea <gildea@lcs.mit.edu>
+;; Make uniquify-min-dir-content 0 truly non-invasive.  gildea 23 May 89
+;; Some cleanup.  uniquify-min-dir-content default 0.  gildea 01 Jun 89
+;; Don't rename to "".  Michael Ernst <mernst@theory.lcs.mit.edu> 15 Jun 94
+;; Add kill-buffer-hook.  Kenneth Manheimer <ken.manheimer@nist.gov> 09 May 95
+;; Add advice for rename-buffer and create-file-buffer, handle dired buffers,
+;;  kill-buffer-rationalize-buffer-names-p, documentation.  mernst 24 May 95
+;; Remove free variables, fix typos.  mernst 5 Jun 95
+;; Efficiently support Emacs 19.27 & earlier.  ken.manheimer, mernst 10 Jun 95
+;; Rename user options to "uniquify-...", add uniquify-reverse-dir-content-p,
+;;  add uniquify-ask-about-buffer-names-p.  king, mernst 13 Jun 95
+;; Prefix functions by "uniquify-..."; rename mnemonic-buffer-names to
+;;  uniquify-buffer-name-style; add 'forward and 'post-forward-angle-brackets
+;;  styles; remove uniquify-reverse-dir-content-p; add
+;;  uniquify-trailing-separator-p.  mernst 4 Aug 95
+
+;; Valuable feedback was provided by
+;; Paul Smith <psmith@baynetworks.com>,
+;; Alastair Burt <burt@dfki.uni-kl.de>,
+;; Bob Weiner <weiner@footloose.sps.mot.com>,
+;; Albert L. Ting <alt@vlibs.com>,
+;; gyro@reasoning.com.
+
+
+;;; Code:
+
+(provide 'uniquify)
+
+;;; User-visible variables
+
+(defvar uniquify-buffer-name-style 'post-forward
+  "*If non-nil, buffer names are uniquified with parts of directory name.
+The value determines the buffer name style and is one of 'forward,
+'reverse, 'post-forward (the default), or 'post-forward-angle-brackets.
+For example, files /foo/bar/mumble/name and /baz/quux/mumble/name
+would be in the following buffers:
+  forward        bar/mumble/name  quux/mumble/name
+  reverse        name\\mumble\\bar  name\\mumble\\quux
+  post-forward   name|bar/mumble  name|quux/mumble
+  post-forward-angle-brackets   name<bar/mumble>  name<quux/mumble>
+  nil            name  name<2>")
+
+(defvar uniquify-after-kill-buffer-p nil
+  "*If non-nil, rerationalize buffer names after a buffer has been killed.
+This can be dangerous if Emacs Lisp code is keeping track of buffers by their
+names (rather than keeping pointers to the buffers themselves).")
+
+(defconst uniquify-ask-about-buffer-names-p nil
+  "*If non-nil, permit user to choose names for buffers with same base file.
+If the user chooses to name a buffer, uniquification is preempted and no
+other buffer names are changed.")
+
+(defvar uniquify-min-dir-content 0
+  "*Minimum parts of directory pathname included in buffer name.")
+
+(defvar uniquify-separator nil
+  "*String separator for buffer name components.
+When `uniquify-buffer-name-style' is 'post-forward, separates
+base file name from directory part in buffer names (default \"|\").
+When `uniquify-buffer-name-style' is 'reverse, separates all
+pathname components (default \"\\\").")
+
+(defvar uniquify-trailing-separator-p nil
+  "*If non-nil, add a pathname separator to dired buffer names.
+If `uniquify-buffer-name-style' is 'forward, add the separator at the end;
+if it's is 'reverse, add the separator at the beginning; otherwise, this
+variable is ignored.")
+
+
+;;; Utilities
+
+(defmacro uniquify-push (item list)
+  (` (setq (, list) (cons (, item) (, list)))))
+
+(defmacro uniquify-fix-list-base (a)
+  (` (car (, a))))
+
+(defmacro uniquify-fix-list-filename (a)
+  (` (car (cdr (, a)))))
+
+(defmacro uniquify-fix-list-buffer (a)
+  (` (car (cdr (cdr (, a))))))
+
+(defmacro uniquify-cadddr (a)
+  (` (car (cdr (cdr (cdr (, a)))))))
+
+;; Internal variables used free
+(defvar uniquify-non-file-buffer-names nil)
+(defvar uniquify-possibly-resolvable nil)
+
+;;; Main entry point.
+
+(defun uniquify-rationalize-file-buffer-names (&optional newbuffile newbuf)
+  "Makes file buffer names unique by adding segments from pathname.
+If `uniquify-min-dir-content' > 0, always pulls that many
+pathname elements.  Arguments cause only a subset of buffers to be renamed."
+  (interactive)
+  (let (fix-list
+	uniquify-non-file-buffer-names
+	(depth uniquify-min-dir-content))
+    (let ((buffers (buffer-list)))
+      (while buffers
+	(let* ((buffer (car buffers))
+	       (bfn (if (eq buffer newbuf)
+			(expand-file-name newbuffile)
+		      (uniquify-buffer-file-name buffer)))
+	       (rawname (and bfn (file-name-nondirectory bfn)))
+	       (deserving (and rawname
+			       (or (not newbuffile)
+				   (equal rawname
+					  (file-name-nondirectory newbuffile))))))
+	  (if deserving
+	      (uniquify-push (list rawname bfn buffer nil) fix-list)
+	    (uniquify-push (list (buffer-name buffer))
+			   uniquify-non-file-buffer-names)))
+	(setq buffers (cdr buffers))))
+    ;; selects buffers whose names may need changing, and others that
+    ;; may conflict.
+    (setq fix-list
+	  (sort fix-list 'uniquify-filename-sort))
+    ;; bringing conflicting names together
+    (uniquify-rationalize-a-list fix-list depth)
+    (mapcar 'uniquify-unrationalized-buffer fix-list)))
+
+(defun uniquify-buffer-file-name (buffer)
+  "Return name of file BUFFER is visiting, or nil if none.
+Works on dired buffers as well as ordinary file-visiting buffers."
+  (or (buffer-file-name buffer)
+      (save-excursion
+	(set-buffer buffer)
+	list-buffers-directory)))
+
+(defun uniquify-filename-sort (s1 s2)
+  (uniquify-filename-lessp
+   (uniquify-fix-list-filename s1) (uniquify-fix-list-filename s2)))
+
+(defun uniquify-filename-lessp (s1 s2)
+  (let ((s1f (file-name-nondirectory s1))
+	(s2f (file-name-nondirectory s2)))
+    (and (not (equal s2f ""))
+	 (or (string-lessp s1f s2f)
+	     (and (equal s1f s2f)
+		  (let ((s1d (file-name-directory s1))
+			(s2d (file-name-directory s2)))
+		    (and (not (<= (length s2d) 1))
+			 (or (<= (length s1d) 1)
+			     (uniquify-filename-lessp
+			      (substring s1d 0 -1)
+			      (substring s2d 0 -1))))))))))
+
+;; Was named do-the-buffers-you-couldnt-rationalize
+(defun uniquify-unrationalized-buffer (item)
+  (or (uniquify-cadddr item) nil))	;maybe better in the future
+
+(defun uniquify-rationalize-a-list (fix-list depth)
+  (let (conflicting-sublist
+	(old-name "")
+	proposed-name uniquify-possibly-resolvable)
+    (while fix-list
+      (let ((item (car fix-list)))
+	(setq proposed-name (uniquify-get-proposed-name item depth))
+	(if (not (equal proposed-name old-name))
+	    (progn
+	      (uniquify-rationalize-conflicting-sublist
+	       conflicting-sublist old-name depth)
+	      (setq conflicting-sublist nil)))
+	(uniquify-push item conflicting-sublist)
+	(setq old-name proposed-name))
+      (setq fix-list (cdr fix-list)))
+    (uniquify-rationalize-conflicting-sublist
+     conflicting-sublist old-name depth)))
+
+(defun uniquify-get-proposed-name (item depth)
+  (let (index
+	(extra-string "")
+	(n depth)
+	(base (uniquify-fix-list-base item))
+	(fn (uniquify-fix-list-filename item)))
+    (while (and (> n 0)
+		(setq index (string-match
+			     (concat "\\(^\\|/[^/]*\\)/"
+				     (regexp-quote extra-string)
+				     (regexp-quote base)
+				     "\\'")
+			     fn)))
+      (setq extra-string (substring fn
+				    (if (zerop index) 0 (1+ index))
+				    ;; (- (length base)) fails for base = "".
+				    ;; Equivalently, we could have used
+				    ;; (apply 'substring ...
+				    ;;        (and (not (string= "" base))
+				    ;;             (list (- (length base)))))
+				    (- (length fn) (length base)))
+	    n (1- n)))
+    (if (zerop n) (setq uniquify-possibly-resolvable t))
+
+
+    ;; Distinguish directories by adding extra separator.
+    (if (and uniquify-trailing-separator-p
+	     (file-directory-p fn)
+	     (not (string-equal base "")))
+	(cond ((eq uniquify-buffer-name-style 'forward)
+	       (setq base (concat base "/")))
+	      ((eq uniquify-buffer-name-style 'reverse)
+	       (setq base (concat (or uniquify-separator "\\") base)))))
+
+    ;; Trim trailing separator on directory part
+    (if (and (not (string-equal extra-string ""))
+	     (or (eq uniquify-buffer-name-style 'post-forward)
+		 (eq uniquify-buffer-name-style 'post-forward-angle-brackets)))
+	(setq extra-string (substring extra-string 0
+				      (- (length extra-string) 1))))
+
+    (cond ((string-equal extra-string "")
+	   base)
+	  ((string-equal base "")
+	   extra-string)
+	  ((eq uniquify-buffer-name-style 'forward)
+	   (concat extra-string base))
+	  ((eq uniquify-buffer-name-style 'reverse)
+	   (concat base (uniquify-reverse-components extra-string)))
+	  ((eq uniquify-buffer-name-style 'post-forward)
+	   (concat base (or uniquify-separator "|") extra-string))
+	  ((eq uniquify-buffer-name-style 'post-forward-angle-brackets)
+	   (concat base "<" extra-string ">"))
+	  (t (error "Bad value for uniquify-buffer-name-style: %s"
+		    uniquify-buffer-name-style)))))
+
+
+;; Deal with conflicting-sublist, which is set by uniquify-rationalize-a-list.
+;; This is only called by uniquify-rationalize-a-list.
+(defun uniquify-rationalize-conflicting-sublist (conflicting-sublist old-name depth)
+  (or (null conflicting-sublist)
+      (and (null (cdr conflicting-sublist))
+	   (not (assoc old-name uniquify-non-file-buffer-names))
+	   (or (and (not (string= old-name ""))
+		    (uniquify-rename-buffer (car conflicting-sublist) old-name))
+	       t))
+      (if uniquify-possibly-resolvable
+	  (uniquify-rationalize-a-list conflicting-sublist (1+ depth)))))
+
+(defun uniquify-rename-buffer (item newname)
+  (let ((buffer (uniquify-fix-list-buffer item)))
+    (if (not (equal newname (buffer-name buffer)))
+	(let ((unset (current-buffer))
+	      ;; avoid hooks on rename-buffer
+	      (uniquify-buffer-name-style nil))
+	  (set-buffer buffer)
+	  (rename-buffer newname)
+	  (set-buffer unset))))
+  (rplaca (nthcdr 3 item) t))
+
+(defun uniquify-reverse-components (instring)
+  (let ((sofar '())
+	(cursor 0)
+	(len (length instring))
+	(sep (or uniquify-separator "\\")))
+    (while (< cursor len)
+      (if (= (aref instring cursor) ?/)
+          (setq sofar (cons sep sofar)
+                cursor (1+ cursor))
+        (let ((first-slash (or (string-match "/" instring cursor) len)))
+          (setq sofar (cons (substring instring cursor first-slash) sofar)
+                cursor first-slash))))
+    (apply (function concat) sofar)))
+
+
+;;; Hooks from the rest of Emacs
+
+;; Emacs 19 (GNU Emacs or XEmacs)
+
+;; The logical place to put all this code is in generate-new-buffer-name.
+;; It's written in C, so we would add a generate-new-buffer-name-function
+;; which, if non-nil, would be called instead of the C.  One problem with
+;; that is that generate-new-buffer-name takes a potential buffer name as
+;; its argument -- not other information, such as what file the buffer will
+;; visit.
+
+;; The below solution works because generate-new-buffer-name is called
+;; only by rename-buffer (which, as of 19.29, is never called from C) and
+;; generate-new-buffer, which is called only by Lisp functions
+;; create-file-buffer and rename-uniquely.  Rename-uniquely generally
+;; isn't used for buffers visiting files, so it's sufficient to hook
+;; rename-buffer and create-file-buffer.  (Setting find-file-hooks isn't
+;; sufficient.)
+
+(defadvice rename-buffer (after rename-buffer-uniquify activate)
+  "Uniquify buffer names with parts of directory name."
+  (if (and uniquify-buffer-name-style
+	   ;; UNIQUE argument
+	   (ad-get-arg 1))
+      (progn
+	(if uniquify-after-kill-buffer-p
+	    ;; call with no argument; rationalize vs. old name as well as new
+	    (uniquify-rationalize-file-buffer-names)
+	  ;; call with argument: rationalize vs. new name only
+	  (uniquify-rationalize-file-buffer-names
+	   (uniquify-buffer-file-name (current-buffer)) (current-buffer)))
+	(setq ad-return-value (buffer-name (current-buffer))))))
+
+(defadvice create-file-buffer (after create-file-buffer-uniquify activate)
+  "Uniquify buffer names with parts of directory name."
+  (if uniquify-buffer-name-style
+      (uniquify-rationalize-file-buffer-names (ad-get-arg 0) ad-return-value)))
+
+;; Buffer deletion
+;; Rerationalize after a buffer is killed, to reduce coinciding buffer names.
+;; This mechanism uses `kill-buffer-hook', which runs *before* deletion.
+;; That means that the kill-buffer-hook function cannot just delete the
+;; buffer -- it has to set something to do the rationalization *later*.
+;; It actually puts another function on `post-command-hook'.  This other
+;; function runs the rationalization and then removes itself from the hook.
+;; Is there a better way to accomplish this?
+;; (This ought to set some global variables so the work is done only for
+;; buffers with names similar to the deleted buffer.  -MDE)
+
+(defun delay-uniquify-rationalize-file-buffer-names ()
+  "Add `delayed-uniquify-rationalize-file-buffer-names' to `post-command-hook'.
+For use on, eg, `kill-buffer-hook', to rationalize *after* buffer deletion."
+  (if (and uniquify-buffer-name-style
+	   uniquify-after-kill-buffer-p)
+      (add-hook 'post-command-hook
+		'delayed-uniquify-rationalize-file-buffer-names)))
+
+(defun delayed-uniquify-rationalize-file-buffer-names ()
+  "Rerationalize buffer names and remove self from `post-command-hook'.
+See also `delay-rationalize-file-buffer-names' for hook setter."
+  (uniquify-rationalize-file-buffer-names)
+  (remove-hook 'post-command-hook
+	       'delayed-uniquify-rationalize-file-buffer-names))
+
+(add-hook 'kill-buffer-hook 'delay-uniquify-rationalize-file-buffer-names)
+
+;;; uniquify.el ends here
+