emacs/lisp/locate.el

;;; locate.el --- interface to the locate command

;; Copyright (C) 1996, 1998, 2001, 2002, 2003, 2004,
;;   2005, 2006 Free Software Foundation, Inc.

;; Author: Peter Breton <pbreton@cs.umb.edu>
;; Keywords: unix files

;; 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; Search a database of files and use dired commands on the result.
;;
;; Locate.el provides an interface to a program which searches a
;; database of file names. By default, this program is the GNU locate
;; command, but it could also be the BSD-style find command, or even a
;; user specified command.
;;
;; To use the BSD-style "fast find", or any other shell command of the
;; form
;;
;;   SHELLPROGRAM  Name-to-find
;;
;; set the variable `locate-command' in your .emacs file.
;;
;;   To use a more complicated expression, create a function which
;; takes a string (the name to find) as input and returns a list.
;; The first element should be the command to be executed, the remaining
;; elements should be the arguments (including the name to find). Then put
;;
;; (setq locate-make-command-line 'my-locate-command-line)
;;
;; in your .emacs, using the name of your function in place of
;; my-locate-command-line.
;;
;; You should make sure that whichever command you use works correctly
;; from a shell prompt. GNU locate and BSD find expect the file databases
;; to either be in standard places or located via environment variables.
;; If the latter, make sure these environment variables are set in
;; your emacs process.
;;
;; Locate-mode assumes that each line output from the locate-command
;; consists exactly of a file name, possibly preceded or trailed by
;; whitespace. If your file database has other information on the line (for
;; example, the file size), you will need to redefine the function
;; `locate-get-file-positions' to return a list consisting of the first
;; character in the file name and the last character in the file name.
;;
;; To use locate-mode, simply type M-x locate and then the string
;; you wish to find. You can use almost all of the dired commands in
;; the resulting *Locate* buffer.  It is worth noting that your commands
;; do not, of course, affect the file database. For example, if you
;; compress a file in the locate buffer, the actual file will be
;; compressed, but the entry in the file database will not be
;; affected. Consequently, the database and the filesystem will be out
;; of sync until the next time the database is updated.
;;
;; The command `locate-with-filter' keeps only lines matching a
;; regular expression; this is often useful to constrain a big search.
;;

;;;;; Building a database of files ;;;;;;;;;
;;
;; You can create a simple files database with a port of the Unix find command
;; and one of the various Windows NT various scheduling utilities,
;; for example the AT command from the NT Resource Kit, WinCron which is
;; included with Microsoft FrontPage, or the shareware NTCron program.
;;
;; To set up a function which searches the files database, do something
;; like this:
;;
;; (defvar locate-fcodes-file       "c:/users/peter/fcodes")
;; (defvar locate-make-command-line 'nt-locate-make-command-line)
;;
;; (defun nt-locate-make-command-line (arg)
;;  (list "grep" "-i" arg locate-fcodes-file))
;;
;;;;;;;; ADVICE For dired-make-relative: ;;;;;;;;;
;;
;; For certain dired commands to work right, you should also include the
;; following in your _emacs/.emacs:
;;
;; (defadvice dired-make-relative (before set-no-error activate)
;;   "For locate mode and Windows, don't return errors"
;;   (if (and (eq   major-mode  'locate-mode)
;; 	   (memq system-type (list 'windows-nt 'ms-dos)))
;;       (ad-set-arg 2 t)
;;     ))
;;
;; Otherwise, `dired-make-relative' will give error messages like
;; "FILENAME: not in directory tree growing at /"


;;; Code:

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

;; Variables

(defvar locate-current-filter nil)

(defgroup locate nil
  "Interface to the locate command."
  :prefix "locate-"
  :group 'external)

(defcustom locate-command "locate"
  "*The executable program used to search a database of files."
  :type 'string
  :group 'locate)

(defvar locate-history-list nil
  "The history list used by the \\[locate] command.")

(defvar locate-grep-history-list nil
  "The history list used by the \\[locate-with-filter] command.")

(defcustom locate-make-command-line 'locate-default-make-command-line
  "*Function used to create the locate command line."
  :type 'function
  :group 'locate)

(defcustom locate-buffer-name "*Locate*"
  "*Name of the buffer to show results from the \\[locate] command."
  :type 'string
  :group 'locate)

(defcustom locate-fcodes-file nil
  "*File name for the database of file names."
  :type '(choice (const :tag "None" nil) file)
  :group 'locate)

(defcustom locate-header-face nil
  "*Face used to highlight the locate header."
  :type '(choice (const :tag "None" nil) face)
  :group 'locate)

;;;###autoload
(defcustom locate-ls-subdir-switches "-al"
  "`ls' switches for inserting subdirectories in `*Locate*' buffers.
This should contain the \"-l\" switch, but not the \"-F\" or \"-b\" switches."
  :type 'string
  :group 'locate
  :version "22.1")

(defcustom locate-update-command "updatedb"
  "The command used to update the locate database."
  :type 'string
  :group 'locate)

(defcustom locate-prompt-for-command nil
  "If non-nil, the locate command prompts for a command to run.
Otherwise, that behavior is invoked via a prefix argument."
  :group 'locate
  :type 'boolean
  )

;; Functions

(defun locate-default-make-command-line (search-string)
  (list locate-command search-string))

(defun locate-word-at-point ()
  (let ((pt (point)))
    (buffer-substring-no-properties
     (save-excursion
       (skip-chars-backward "-a-zA-Z0-9.")
       (point))
     (save-excursion
       (skip-chars-forward "-a-zA-Z0-9.")
       (skip-chars-backward "." pt)
       (point)))))

;;;###autoload
(defun locate (search-string &optional filter)
  "Run the program `locate', putting results in `*Locate*' buffer.
With prefix arg, prompt for the locate command to run."
  (interactive
      (list
       (if (or (and current-prefix-arg
		    (not locate-prompt-for-command))
	       (and (not current-prefix-arg) locate-prompt-for-command))
	   (let ((locate-cmd (funcall locate-make-command-line "")))
	     (read-from-minibuffer
	      "Run locate (like this): "
	      (cons
	       (concat (car locate-cmd) "  "
		       (mapconcat 'identity (cdr locate-cmd) " "))
		       (+ 2 (length (car locate-cmd))))
	      nil nil 'locate-history-list))
	 (let* ((default (locate-word-at-point))
	       (input
		(read-from-minibuffer
		 (if  (> (length default) 0)
		     (format "Locate (default %s): " default)
		   (format "Locate: "))
		 nil nil nil 'locate-history-list default t)))
	       (and (equal input "") default
		    (setq input default))
	       input))))
  (if (equal search-string "")
      (error "Please specify a filename to search for"))
  (let* ((locate-cmd-list (funcall locate-make-command-line search-string))
	 (locate-cmd (car locate-cmd-list))
	 (locate-cmd-args (cdr locate-cmd-list))
	 (run-locate-command
	  (or (and current-prefix-arg (not locate-prompt-for-command))
	      (and (not current-prefix-arg) locate-prompt-for-command)))
	 )

    ;; Find the Locate buffer
    (save-window-excursion
      (set-buffer (get-buffer-create locate-buffer-name))
      (locate-mode)
      (let ((inhibit-read-only t)
	    (buffer-undo-list t))
	(erase-buffer)

	(setq locate-current-filter filter)

	(if run-locate-command
	    (shell-command search-string locate-buffer-name)
	  (apply 'call-process locate-cmd nil t nil locate-cmd-args))

	(and filter
	     (locate-filter-output filter))

	(locate-do-setup search-string)
	))
    (and (not (string-equal (buffer-name) locate-buffer-name))
	(switch-to-buffer-other-window locate-buffer-name))

    (run-hooks 'dired-mode-hook)
    (dired-next-line 3)			;move to first matching file.
    (run-hooks 'locate-post-command-hook)
    )
  )

;;;###autoload
(defun locate-with-filter (search-string filter)
  "Run the locate command with a filter.

The filter is a regular expression. Only results matching the filter are
shown; this is often useful to constrain a big search."
  (interactive
   (list (read-from-minibuffer "Locate: " nil nil
			       nil 'locate-history-list)
	 (read-from-minibuffer "Filter: " nil nil
			       nil 'locate-grep-history-list)))
  (locate search-string filter))

(defun locate-filter-output (filter)
  "Filter output from the locate command."
  (goto-char (point-min))
  (delete-non-matching-lines filter))

(defvar locate-mode-map nil
  "Local keymap for Locate mode buffers.")
(if locate-mode-map
    nil

   (require 'dired)

   (setq locate-mode-map (copy-keymap dired-mode-map))

   ;; Undefine Useless Dired Menu bars
   (define-key locate-mode-map [menu-bar Dired]   'undefined)
   (define-key locate-mode-map [menu-bar subdir]  'undefined)

   (define-key locate-mode-map [menu-bar mark executables] 'undefined)
   (define-key locate-mode-map [menu-bar mark directory]   'undefined)
   (define-key locate-mode-map [menu-bar mark directories] 'undefined)
   (define-key locate-mode-map [menu-bar mark symlinks]    'undefined)

   (define-key locate-mode-map [M-mouse-2] 'locate-mouse-view-file)
   (define-key locate-mode-map "\C-c\C-t"  'locate-tags)

   (define-key locate-mode-map "l"       'locate-do-redisplay)
   (define-key locate-mode-map "U"       'dired-unmark-all-files)
   (define-key locate-mode-map "V"       'locate-find-directory)
)

;; This variable is used to indent the lines and then to search for
;; the file name
(defconst locate-filename-indentation 4
  "The amount of indentation for each file.")

(defun locate-get-file-positions ()
  (save-excursion
    (end-of-line)
    (let ((eol (point)))
      (beginning-of-line)

      ;; Assumes names end at the end of the line
      (forward-char locate-filename-indentation)
      (list (point) eol))))

;; From SQL-mode
(defun locate-current-line-number ()
  "Return the current line number, as an integer."
  (+ (count-lines (point-min) (point))
     (if (eq (current-column) 0)
	 1
       0)))

(defun locate-get-filename ()
  (let ((pos    (locate-get-file-positions))
	(lineno (locate-current-line-number)))
    (and (not (eq lineno 1))
	 (not (eq lineno 2))
	 (buffer-substring (elt pos 0) (elt pos 1)))))

(defun locate-main-listing-line-p ()
  "Return t if current line contains a file name listed by locate.
This function returns nil if the current line either contains no
file name or is inside a subdirectory."
  (save-excursion
    (forward-line 0)
    (looking-at (concat "."
			(make-string (1- locate-filename-indentation) ?\ )
			"\\(/\\|[A-Za-z]:\\)"))))

(defun locate-mouse-view-file (event)
  "In Locate mode, view a file, using the mouse."
  (interactive "@e")
  (save-excursion
    (goto-char (posn-point (event-start event)))
    (if (locate-main-listing-line-p)
	(view-file (locate-get-filename))
      (message "This command only works inside main listing."))))

;; Define a mode for locate
;; Default directory is set to "/" so that dired commands, which
;; expect to be in a tree, will work properly
(defun locate-mode ()
  "Major mode for the `*Locate*' buffer made by \\[locate].
\\<locate-mode-map>\
In that buffer, you can use almost all the usual dired bindings.
\\[locate-find-directory] visits the directory of the file on the current line.

Operating on listed files works, but does not always
automatically update the buffer as in ordinary Dired.
This is true both for the main listing and for subdirectories.
Reverting the buffer using \\[revert-buffer] deletes all subdirectories.
Specific `locate-mode' commands, such as \\[locate-find-directory],
do not work in subdirectories.

\\{locate-mode-map}"
  ;; Not to be called interactively.
  (kill-all-local-variables)
  ;; Avoid clobbering this variable
  (make-local-variable 'dired-subdir-alist)
  (use-local-map             locate-mode-map)
  (setq major-mode          'locate-mode
        mode-name           "Locate"
        default-directory   "/"
	buffer-read-only    t
	selective-display   t)
  (dired-alist-add-1 default-directory (point-min-marker))
  (set (make-local-variable 'dired-directory) "/")
  (set (make-local-variable 'dired-subdir-switches) locate-ls-subdir-switches)
  (setq dired-switches-alist nil)
  (make-local-variable 'directory-listing-before-filename-regexp)
  ;; This should support both Unix and Windoze style names
  (setq directory-listing-before-filename-regexp
	(concat "^."
		(make-string (1- locate-filename-indentation) ?\ )
		"\\(/\\|[A-Za-z]:\\)\\|"
		(default-value 'directory-listing-before-filename-regexp)))
  (make-local-variable 'dired-actual-switches)
  (setq dired-actual-switches "")
  (make-local-variable 'dired-permission-flags-regexp)
  (setq dired-permission-flags-regexp
	(concat "^.\\("
		(make-string (1- locate-filename-indentation) ?\ )
		"\\)\\|"
		(default-value 'dired-permission-flags-regexp)))
  (make-local-variable 'revert-buffer-function)
  (setq revert-buffer-function 'locate-update)
  (set (make-local-variable 'page-delimiter) "\n\n")
  (run-mode-hooks 'locate-mode-hook))

(defun locate-do-setup (search-string)
  (goto-char (point-min))
  (save-excursion

    ;; Nothing returned from locate command?
    (and (eobp)
	 (progn
	   (kill-buffer locate-buffer-name)
	   (if locate-current-filter
	       (error "Locate: no match for %s in database using filter %s"
		      search-string locate-current-filter)
	     (error "Locate: no match for %s in database" search-string))))

    (locate-insert-header search-string)

    (while (not (eobp))
      (insert-char ?\  locate-filename-indentation t)
      (locate-set-properties)
      (forward-line 1)))
  (goto-char (point-min)))

(defun locate-set-properties ()
  (save-excursion
    (let ((pos (locate-get-file-positions)))
      (dired-insert-set-properties (elt pos 0) (elt pos 1)))))

(defun locate-insert-header (search-string)
  ;; There needs to be a space before `Matches, because otherwise,
  ;; `*!" would erase the `M'.  We can not use two spaces, or the line
  ;; would mistakenly fit `dired-subdir-regexp'.
  (let ((locate-format-string "  /:\n Matches for %s")
	(locate-regexp-match
	 (concat " *Matches for \\(" (regexp-quote search-string) "\\)"))
	(locate-format-args (list search-string))
	)

    (and locate-fcodes-file
	(setq locate-format-string
	      (concat locate-format-string " in %s")
	      locate-regexp-match
	      (concat locate-regexp-match
		      " in \\("
		      (regexp-quote locate-fcodes-file)
		      "\\)")
	      locate-format-args
	      (append (list locate-fcodes-file) locate-format-args)))

    (and locate-current-filter
	(setq locate-format-string
	      (concat locate-format-string " using filter %s")
	      locate-regexp-match
	      (concat locate-regexp-match
		      " using filter "
		      "\\("
		      (regexp-quote locate-current-filter)
		      "\\)")
	      locate-format-args
	      (append (list locate-current-filter) locate-format-args)))

    (setq locate-format-string
	  (concat locate-format-string ":\n\n")
	  locate-regexp-match
	  (concat locate-regexp-match ":\n"))

    (insert (apply 'format locate-format-string (reverse locate-format-args)))

    (save-excursion
      (goto-char (point-min))
      (forward-line 1)
      (if (not (looking-at locate-regexp-match))
	  nil
	(add-text-properties (match-beginning 1) (match-end 1)
			     (list 'face locate-header-face))
	(and (match-beginning 2)
	     (add-text-properties (match-beginning 2) (match-end 2)
				  (list 'face locate-header-face)))
	(and (match-beginning 3)
	     (add-text-properties (match-beginning 3) (match-end 3)
				  (list 'face locate-header-face)))
	))))

(defun locate-tags ()
  "Visit a tags table in `*Locate*' mode."
  (interactive)
  (if (locate-main-listing-line-p)
      (let ((tags-table (locate-get-filename)))
	(and (y-or-n-p (format "Visit tags table %s? " tags-table))
	     (visit-tags-table tags-table)))
    (message "This command only works inside main listing.")))

;; From Stephen Eglen <stephen@cns.ed.ac.uk>
(defun locate-update (ignore1 ignore2)
  "Update the locate database.
Database is updated using the shell command in `locate-update-command'."
  (let ((str (car locate-history-list)))
    (cond ((yes-or-no-p "Update locate database (may take a few seconds)? ")
	   (shell-command locate-update-command)
	   (locate str)))))

;;; Modified three functions from `dired.el':
;;;   dired-find-directory,
;;;   dired-find-directory-other-window
;;;   dired-get-filename

(defun locate-find-directory ()
  "Visit the directory of the file mentioned on this line."
  (interactive)
  (if (locate-main-listing-line-p)
      (let ((directory-name (locate-get-dirname)))
	(if (file-directory-p directory-name)
	    (find-file directory-name)
	  (if (file-symlink-p directory-name)
	      (error "Directory is a symlink to a nonexistent target")
	    (error "Directory no longer exists; run `updatedb' to update database"))))
    (message "This command only works inside main listing.")))

(defun locate-find-directory-other-window ()
  "Visit the directory of the file named on this line in other window."
  (interactive)
  (find-file-other-window (locate-get-dirname)))

(defun locate-get-dirname ()
  "Return the directory name of the file mentioned on this line."
  (let (file (filepos (locate-get-file-positions)))
    (if (setq file (buffer-substring (nth 0 filepos) (nth 1 filepos)))
	(progn
	  ;; Get rid of the mouse-face property that file names have.
	  (set-text-properties 0 (length file) nil file)
	  (setq file (file-name-directory file))
	  ;; Unquote names quoted by ls or by dired-insert-directory.
	  ;; Using read to unquote is much faster than substituting
	  ;; \007 (4 chars) -> ^G  (1 char) etc. in a lisp loop.
	  (setq file
		(read
		 (concat "\""
			 ;; some ls -b don't escape quotes, argh!
			 ;; This is not needed for GNU ls, though.
			 (or (dired-string-replace-match
			      "\\([^\\]\\|\\`\\)\"" file "\\1\\\\\"" nil t)
			     file)
			 "\"")))))
    (and file buffer-file-coding-system
	 (not file-name-coding-system)
	 (setq file (encode-coding-string file buffer-file-coding-system)))
    file))

;; Only for GNU locate
(defun locate-in-alternate-database  (search-string database)
  "Run the GNU locate command, using an alternate database."
  (interactive
      (list
       (progn
	 ;; (require 'locate)
	 (read-from-minibuffer "Locate: " nil nil
			       nil 'locate-history-list))
       (read-file-name "Locate using Database: " )
       ))
  (or (file-exists-p database)
      (error "Database file %s does not exist" database))
  (let ((locate-make-command-line
	 (function (lambda (string)
		     (cons locate-command
			   (list (concat "--database="
					 (expand-file-name database))
				 string))))))
    (locate search-string)))

(defun locate-do-redisplay (&optional arg test-for-subdir)
  "Like `dired-do-redisplay', but adapted for `*Locate*' buffers."
  (interactive "P\np")
  (if (string= (dired-current-directory) "/")
      (message "This command only works in subdirectories.")
    (let ((dired-actual-switches locate-ls-subdir-switches))
      (dired-do-redisplay arg test-for-subdir))))

(provide 'locate)

;;; arch-tag: 60c4d098-b5d5-4b3c-a3e0-51a2e9f43898
;;; locate.el ends here