emacs/lisp/uniquify.el

;;; uniquify.el --- unique buffer names dependent on file name

;; Copyright (c) 1989, 1995, 1996, 1997, 2001 Free Software Foundation, Inc.

;; Author: Dick King <king@reasoning.com>
;; Maintainer: FSF
;; Keywords: files
;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, 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 file name 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, do (require 'uniquify)
;; and set uniquify-buffer-name-style to one of its non-nil alternative values.

;; For other options, see "User-visible variables", below.

;; A version of uniquify.el that works under Emacs 18, Emacs 19, XEmacs,
;; and InfoDock is available from the maintainer.

;;; Change Log:

;; Originally by Dick King <king@reasoning.com> 15 May 86
;; Converted for Emacs 18 by Stephen Gildea <gildea@stop.mail-abuse.org>
;; 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
;; Don't call expand-file-name on nil.  mernst 7 Jan 96
;; Check whether list-buffers-directory is bound.  mernst 11 Oct 96
;; Ignore non-file non-dired buffers. Colin Rafferty <craffert@ml.com> 3 Mar 97
;; Use last component, not "", for file name of directories.  mernst 27 Jun 97
;; Use directory-file-name; code cleanup.  mernst 6 Sep 97
;; Add uniquify-ignore-buffers-re.
;;  Andre Srinivasan <andre@visigenic.com> 9 Sep 97
;; Add uniquify-list-buffers-directory-modes
;;   Stefan Monnier <monnier@cs.yale.edu> 17 Nov 2000
;; Algorithm and data structure changed to reduce consing with lots of buffers
;;   Francesco Potort<72> <pot@gnu.org> (ideas by rms and monnier) 2001-07-18

;; 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,
;; Bryan O'Sullivan <bos@eng.sun.com>.


;;; Code:

(eval-when-compile (require 'cl))

;;; User-visible variables

(defgroup uniquify nil
  "Unique buffer names dependent on file name"
  :group 'applications)


(defcustom uniquify-buffer-name-style nil
  "*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', or `post-forward-angle-brackets'.
For example, files `/foo/bar/mumble/name' and `/baz/quux/mumble/name'
would have the following buffer names in the various styles:
  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>"
  :type '(radio (const forward)
		(const reverse)
		(const post-forward)
		(const post-forward-angle-brackets)
		(const :tag "standard Emacs behavior (nil)" nil))
  :require 'uniquify)

(defcustom 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)."
  :type 'boolean)

(defcustom 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."
  :type 'boolean)

;; The default value matches certain Gnus buffers.
(defcustom uniquify-ignore-buffers-re "^\\*\\(un\\)?sent "
  "*Regular expression matching buffer names that should not be uniquified.
For instance, set this to \"^draft-[0-9]+$\" to avoid having uniquify rename
draft buffers even if `uniquify-after-kill-buffer-p' is non-nil and the
visited file name isn't the same as that of the buffer."
  :type '(choice (const :tag "Uniquify all buffers" nil) regexp))

(defcustom uniquify-min-dir-content 0
  "*Minimum number of directory name components included in buffer name."
  :type 'integer)

(defcustom 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
file name components (default \"\\\")."
  :type '(choice (const nil) string))

(defcustom uniquify-trailing-separator-p nil
  "*If non-nil, add a file name separator to dired buffer names.
If `uniquify-buffer-name-style' is `forward', add the separator at the end;
if it is `reverse', add the separator at the beginning; otherwise, this
variable is ignored."
  :type 'boolean)

(defvar uniquify-list-buffers-directory-modes '(dired-mode cvs-mode)
  "List of modes for which uniquify should obey `list-buffers-directory'.
That means that when `buffer-file-name' is set to nil, `list-buffers-directory'
contains the name of the directory which the buffer is visiting.")

;;; Utilities

;; uniquify-fix-list data structure
(defstruct (uniquify-item
	    (:constructor nil) (:copier nil)
	    (:constructor uniquify-make-item (base dirname buffer proposed)))
  base dirname buffer proposed)

;; Internal variables used free
(defvar uniquify-possibly-resolvable nil)

(defvar uniquify-managed nil
  "Non-nil if the name of this buffer is managed by uniquify.
It actually holds the list of `uniquify-item's corresponding to the conflict.")
(make-variable-buffer-local 'uniquify-managed)
(put 'uniquify-managed 'permanent-local t)

;;; Main entry point.

(defun uniquify-rationalize-file-buffer-names (newbuffile newbuf)
  "Make file buffer names unique by adding segments from file name.
If `uniquify-min-dir-content' > 0, always pulls that many
file name elements.
Arguments NEWBUFFILE and NEWBUF cause only a subset of buffers to be renamed."
  (interactive)
  (if (null newbuffile)
      (with-current-buffer newbuf (setq uniquify-managed nil))
    (setq newbuffile (expand-file-name (directory-file-name newbuffile)))
    (let ((fix-list nil)
	  (base (file-name-nondirectory newbuffile)))
      (dolist (buffer (buffer-list))
	(let ((bufname (buffer-name buffer))
	      bfn)
	  (when (and (not (and uniquify-ignore-buffers-re
			       (string-match uniquify-ignore-buffers-re
					     bufname)))
		     ;; Only try to rename buffers we actually manage.
		     (or (buffer-local-value 'uniquify-managed buffer)
			 (eq buffer newbuf))
		     (setq bfn (if (eq buffer newbuf) newbuffile
				 (uniquify-buffer-file-name buffer)))
		     (equal (file-name-nondirectory bfn) base))
	    (when (setq bfn (file-name-directory bfn)) ;Strip off the `base'.
	      (setq bfn (directory-file-name bfn)))    ;Strip trailing slash.
	    (push (uniquify-make-item base bfn buffer
				      (uniquify-get-proposed-name base bfn))
		  fix-list))))
      ;; selects buffers whose names may need changing, and others that
      ;; may conflict, then bring conflicting names together
      (uniquify-rationalize fix-list))))

;; uniquify's version of buffer-file-name; result never contains trailing slash
(defun uniquify-buffer-file-name (buffer)
  "Return name of file BUFFER is visiting, or nil if none.
Works on ordinary file-visiting buffers and buffers whose mode is mentioned
in `uniquify-list-buffers-directory-modes', otherwise returns nil."
  (or (buffer-file-name buffer)
      (with-current-buffer buffer
	(and
	 (memq major-mode uniquify-list-buffers-directory-modes)
	 (if (boundp 'list-buffers-directory) ; XEmacs mightn't define this
	     (and list-buffers-directory
		  (directory-file-name list-buffers-directory))
	   ;; don't use default-directory if dired-directory is nil
	   (and dired-directory
		(expand-file-name
		 (directory-file-name
		  (if (consp dired-directory)
		      (car dired-directory)
		    dired-directory)))))))))

(defun uniquify-rerationalize-w/o-cb (fix-list)
  "Re-rationalize the buffers in FIX-LIST, but ignoring current-buffer."
  (let ((new-fix-list nil))
    (dolist (item fix-list)
      (let ((buf (uniquify-item-buffer item)))
	(unless (or (eq buf (current-buffer)) (not (buffer-live-p buf)))
	  ;; Reset the proposed names.
	  (setf (uniquify-item-proposed item)
		(uniquify-get-proposed-name (uniquify-item-base item)
					    (uniquify-item-dirname item)))
	  (push item new-fix-list))))
    (when new-fix-list
      (uniquify-rationalize new-fix-list))))

(defun uniquify-rationalize (fix-list)
  ;; Set up uniquify to re-rationalize after killing/renaming
  ;; if there is a conflict.
  (dolist (fix fix-list)
    (with-current-buffer (uniquify-item-buffer fix)
      (setq uniquify-managed fix-list)))
  ;; If uniquify-min-dir-content is 0, this will end up just
  ;; passing fix-list to uniquify-rationalize-conflicting-sublist.
  (uniquify-rationalize-a-list fix-list))

(defun uniquify-item-greaterp (item1 item2)
  (string-lessp (uniquify-item-proposed item2)
		(uniquify-item-proposed item1)))

(defun uniquify-rationalize-a-list (fix-list &optional depth)
  (unless depth (setq depth uniquify-min-dir-content))
  (let (conflicting-sublist	; all elements have the same proposed name
	(old-proposed "")
	proposed)
    ;; Divide fix-list into items with same proposed names and pass them
    ;; to uniquify-rationalize-conflicting-sublist.
    (dolist (item (sort fix-list 'uniquify-item-greaterp))
      (setq proposed (uniquify-item-proposed item))
      (unless (equal proposed old-proposed)
	(uniquify-rationalize-conflicting-sublist conflicting-sublist
						  old-proposed depth)
	(setq conflicting-sublist nil))
      (push item conflicting-sublist)
      (setq old-proposed proposed))
    (uniquify-rationalize-conflicting-sublist conflicting-sublist
					      old-proposed depth)))

(defun uniquify-get-proposed-name (base dirname &optional depth)
  (unless depth (setq depth uniquify-min-dir-content))
  (assert (equal (directory-file-name dirname) dirname)) ;No trailing slash.

  ;; Distinguish directories by adding extra separator.
  (if (and uniquify-trailing-separator-p
	   (file-directory-p (expand-file-name base dirname))
	   (not (string-equal base "")))
      (cond ((eq uniquify-buffer-name-style 'forward)
	     (setq base (file-name-as-directory base)))
	    ;; (setq base (concat base "/")))
	    ((eq uniquify-buffer-name-style 'reverse)
	     (setq base (concat (or uniquify-separator "\\") base)))))

  (let ((extra-string nil)
	(n depth))
    (while (and (> n 0) dirname)
      (let ((file (file-name-nondirectory dirname)))
	(when (setq dirname (file-name-directory dirname))
	  (setq dirname (directory-file-name dirname)))
	(setq n (1- n))
	(push (if (zerop (length file)) ;nil or "".
		  (prog1 "" (setq dirname nil))	;Could be `dirname' iso "".
		file)
	      extra-string)))
    (when (zerop n)
      (if (and dirname extra-string
	       (equal dirname (file-name-directory dirname)))
	  ;; We're just before the root.  Let's add the leading / already.
	  ;; With "/a/b"+"/c/d/b" this leads to "/a/b" and "d/b" but with
	  ;; "/a/b"+"/c/a/b" this leads to "/a/b" and "a/b".
	  (push "" extra-string))
      (setq uniquify-possibly-resolvable t))

    (cond
     ((null extra-string) base)
     ((string-equal base "") ;Happens for dired buffers on the root directory.
      (mapconcat 'identity extra-string "/"))
     ((eq uniquify-buffer-name-style 'reverse)
      (mapconcat 'identity
		 (cons base (nreverse extra-string))
		 (or uniquify-separator "\\")))
     ((eq uniquify-buffer-name-style 'forward)
      (mapconcat 'identity (nconc extra-string (list base))
		 "/"))
     ((eq uniquify-buffer-name-style 'post-forward)
      (concat base (or uniquify-separator "|")
	      (mapconcat 'identity extra-string "/")))
     ((eq uniquify-buffer-name-style 'post-forward-angle-brackets)
      (concat base "<" (mapconcat 'identity extra-string "/")
	      ">"))
     (t (error "Bad value for uniquify-buffer-name-style: %s"
	       uniquify-buffer-name-style)))))


;; Deal with conflicting-sublist, all of whose elements have identical
;; "base" components.
(defun uniquify-rationalize-conflicting-sublist (conf-list old-name depth)
  (when conf-list
    (if (or (cdr conf-list)
	    ;; Check that the proposed name doesn't conflict with some
	    ;; existing buffer.
	    (let ((buf (get-buffer old-name)))
	      (and buf (not (eq buf (uniquify-item-buffer (car conf-list)))))))
	(when uniquify-possibly-resolvable
	  (setq uniquify-possibly-resolvable nil
		depth (1+ depth))
	  (dolist (item conf-list)
	    (setf (uniquify-item-proposed item)
		  (uniquify-get-proposed-name
		   (uniquify-item-base item)
		   (uniquify-item-dirname item)
		   depth)))
	  (uniquify-rationalize-a-list conf-list depth))
      (unless (string= old-name "")
	(uniquify-rename-buffer (car conf-list) old-name)))))


(defun uniquify-rename-buffer (item newname)
  (let ((buffer (uniquify-item-buffer item)))
    (unless (equal newname (buffer-name buffer))
      (with-current-buffer buffer
	(let ((uniquify-buffer-name-style nil))	;Avoid hooks on rename-buffer.
	  ;; Pass the `unique' arg, so the advice doesn't mark it as unmanaged.
	  (rename-buffer newname t))))))

;;; Hooks from the rest of Emacs

;; 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-hook isn't
;; sufficient.)

(defadvice rename-buffer (after rename-buffer-uniquify activate)
  "Uniquify buffer names with parts of directory name."
  (uniquify-maybe-rerationalize-w/o-cb)
  (if (null (ad-get-arg 1))		; no UNIQUE argument.
      ;; Mark this buffer so it won't be renamed by uniquify.
      (setq uniquify-managed nil)
    (when uniquify-buffer-name-style
      ;; Rerationalize w.r.t the new name.
      (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 uniquify-maybe-rerationalize-w/o-cb ()
  "Re-rationalize buffer names, ignoring current buffer.
For use on `kill-buffer-hook'."
  (if (and (cdr uniquify-managed)
	   uniquify-buffer-name-style
	   uniquify-after-kill-buffer-p)
      (uniquify-rerationalize-w/o-cb uniquify-managed)))

;; Ideally we'd like to add it buffer-locally, but that doesn't work
;; because kill-buffer-hook is not permanent-local :-(
(add-hook 'kill-buffer-hook 'uniquify-maybe-rerationalize-w/o-cb)

(provide 'uniquify)
;;; uniquify.el ends here