Re: insert-directory

[Luc Teirlinck]

Below is the latest version of my patch to make `i' in *Locate*
buffers work.

Before installing it I want to point out the following:

1.  Making `i' work requires making the *Locate* buffer read-only.
    Otherwise, with inserted directories, trying to use `undo' and
    similar commands will result in complete confusion.  Is there any
    reason for the *Locate* buffer _not_ to be read-only?

2.  It rebinds mouse-2 to the usual dired binding, to avoid confusion.
    It binds locate-mouse-view-file (the current mouse-2 binding) to
    M-mouse-2, because the usual binding for M-mouse-2, yanking the
    secondary selection, becomes meaningless if the *Locate* buffer is
    made read-only.

Are the two above changes OK?

3.  Making `i' work _absolutely perfectly_ in _every possible aspect_
    seems theoretically impossible, because the buffer is not in
    dired-mode.

4.  It is not completely clear whether `i' was ever really intended to
    work in *Locate* buffers.  Several other dired commands like `<'
    and `>' do not seem to work either.  (After my patch they do work
    inside subdirectories, but still not in the main listing.)

In spite of (3), all commands I tried out (and I tried many) seem to
work perfectly in subdirectories (after applying my latest patch
below).  However, I somehow have the feeling that, even though I could
not find any, there must be _some_ commands that malfunction, since
dired commands expect the buffer to be in dired-mode.

_Without_ my patch, `i' correctly lists the subdirectory, even on
GNU/Linux (since I installed my patch to files.el), but dired commands
do not work in it.

===File ~/locate-diff=======================================
*** locate.el   20 May 2004 17:14:36 -0500      1.22
--- locate.el   26 May 2004 13:19:04 -0500      
***************
*** 223,241 ****
      (save-window-excursion
        (set-buffer (get-buffer-create locate-buffer-name))
        (locate-mode)
!       (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))
  
--- 223,242 ----
      (save-window-excursion
        (set-buffer (get-buffer-create locate-buffer-name))
        (locate-mode)
!       (let ((inhibit-read-only 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))
  
***************
*** 281,287 ****
     (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 [mouse-2]   'locate-mouse-view-file)
     (define-key locate-mode-map "\C-c\C-t"  'locate-tags)
  
     (define-key locate-mode-map "U"       'dired-unmark-all-files)
--- 282,289 ----
     (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 "i"         'locate-maybe-insert-subdir)
     (define-key locate-mode-map "\C-c\C-t"  'locate-tags)
  
     (define-key locate-mode-map "U"       'dired-unmark-all-files)
***************
*** 318,329 ****
         (not (eq lineno 2))
         (buffer-substring (elt pos 0) (elt pos 1)))))
  
  (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)))
!     (view-file (locate-get-filename))))
  
  ;; Define a mode for locate
  ;; Default directory is set to "/" so that dired commands, which
--- 320,359 ----
         (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."))))
! 
! (defun locate-maybe-insert-subdir (dirname &optional
!                                          switches no-error-if-not-dir-p)
!   "Like `dired-maybe-insert-subdir', but works in `locate-mode'.
! `locate-mode' needs a special command for this to replace its own
! binding of `dired-actual-switches' with \"-al\", when called
! interactively.  As with `dired-maybe-insert-subdir', you can
! specify your own switches by providing a numeric prefix argument,
! but you can not specify the \"-F\" switch.  For proper
! functioning, you should specify the \"-l\" switch."
!   (interactive
!    (list (dired-get-filename)
!        (if current-prefix-arg
!            (read-string "Switches for listing: " "-al")
!          "-al")))
!   (dired-maybe-insert-subdir dirname switches no-error-if-not-dir-p))
  
  ;; Define a mode for locate
  ;; Default directory is set to "/" so that dired commands, which
***************
*** 345,362 ****
    (make-local-variable 'dired-move-to-filename-regexp)
    ;; This should support both Unix and Windoze style names
    (setq dired-move-to-filename-regexp
!       (concat "."
                (make-string (1- locate-filename-indentation) ?\ )
!               "\\(/\\|[A-Za-z]:\\)"))
    (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) ?\ )
!               "\\)"))
    (make-local-variable 'revert-buffer-function)
    (setq revert-buffer-function 'locate-update)
    (run-hooks 'locate-mode-hook))
  
  (defun locate-do-setup (search-string)
--- 375,395 ----
    (make-local-variable 'dired-move-to-filename-regexp)
    ;; This should support both Unix and Windoze style names
    (setq dired-move-to-filename-regexp
!       (concat "^."
                (make-string (1- locate-filename-indentation) ?\ )
!               "\\(/\\|[A-Za-z]:\\)\\|"
!               (default-value 'dired-move-to-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)
+   (setq buffer-read-only t)
    (run-hooks 'locate-mode-hook))
  
  (defun locate-do-setup (search-string)
***************
*** 386,392 ****
        (dired-insert-set-properties (elt pos 0) (elt pos 1)))))
  
  (defun locate-insert-header (search-string)
!   (let ((locate-format-string "Matches for %s")
        (locate-regexp-match
         (concat " *Matches for \\(" (regexp-quote search-string) "\\)"))
        (locate-format-args (list search-string))
--- 419,425 ----
        (dired-insert-set-properties (elt pos 0) (elt pos 1)))))
  
  (defun locate-insert-header (search-string)
!   (let ((locate-format-string " Matches for %s")
        (locate-regexp-match
         (concat " *Matches for \\(" (regexp-quote search-string) "\\)"))
        (locate-format-args (list search-string))
***************
*** 439,447 ****
  (defun locate-tags ()
    "Visit a tags table in `*Locate*' mode."
    (interactive)
!   (let ((tags-table (locate-get-filename)))
!     (and (y-or-n-p (format "Visit tags table %s? " tags-table))
!        (visit-tags-table tags-table))))
  
  ;; From Stephen Eglen <address@hidden>
  (defun locate-update (ignore1 ignore2)
--- 472,482 ----
  (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 <address@hidden>
  (defun locate-update (ignore1 ignore2)
***************
*** 460,471 ****
  (defun locate-find-directory ()
    "Visit the directory of the file mentioned on this line."
    (interactive)
!   (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")))))
  
  (defun locate-find-directory-other-window ()
    "Visit the directory of the file named on this line in other window."
--- 495,508 ----
  (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."
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