Re: [PATCH] Lazy wdired preprocessing - BUG

[Arthur Miller <arthur.miller@live.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>>> +(defvar wdired-perm-beg) ;; Column where the permission bits start
>>>> +(defvar wdired-perm-end) ;; Column where the permission bits stop
>>> I think this should use "--" in the names since they are internal variables.
>> I just followed naming as already was in wdired.
>
> I know; fixing all the old code to use such conventions is hard, but
> I try and make sure that new code at least follows those conventions ;-)
>
>>> `current-column` can be somewhat costly, so we should refrain from
>>> calling it twice gratuitously.  And here we can even take advantage of
>>> the (rarely used and rarely applicable) multi-arg form of `<=` to fix
>>> that "for free":
>> Ok. Didn't know that (current-column) was expensive. I use now a good 'nuff
>> implementation for this purpose (wdired--current-column).
>
> Oh, not *that* costly.  Just in the sense that it's
> better not to feel free to call it redundantly.
> But, I think `wdired--current-column` looks fine: it completely
> side-steps the question of what happens if some of the text is
> currently invisible.
>
>> It's all yours now. I don't think I will have more time nor possibility
>> to work on this, so if this one is not good enough, you will to finnish
>> it on your own, or someone else could help. We are waiting a kid any
>> day now, so no hobby programming for quite some time over for me :-).
>
> Would it be time to plug in Richard's endorsement of reproduction here?
>
> I pushed your change with the following additional patch on top,

I have just rebuild with the new patch. I see a small bug: when entered
wdired mode, and trying to do a very first change, it requires two
keypresses. The first key press, I think, gets consumed in first call to
wdired--self insert, so user is required to press again a key to do
actual edit.

I was struggling with that one so one of the reasons I pushed key event back
onto the queue was that one.


> +        (let ((cmd (lookup-key map (this-command-keys))))
> +          (call-interactively (or cmd 'self-insert-command)))))))

I am not sure how that part works, so I am not attempting to suggest a
change, not sure if it's that part, but I think the keypress is
consumed in call to preprocess function. 

>
>         Stefan
>
>
> commit ed6b9586d74795605debf614bd4328611e1f1c22
> Author: Stefan Monnier <monnier@iro.umontreal.ca>
> Date:   Sat Mar 27 10:54:10 2021 -0400
>
>     * lisp/wdired.el: Fix minor regressions and simplify a bit
>     
>     Use `wdired--current-column` more consistently to avoid mayhem when it
>     doesn't return the same result as `current-column`.
>     
>     (wdired--col-perm): Remove, redundant with `wdired--perm-beg`.
>     (wdired-change-to-wdired-mode): Don't error in empty directory.
>     (wdired--set-permission-bounds): Set `wdired--perm-beg` when we can't
>     find permissions.  Move `wdired--perm-beg` 1 char further (like
>     `wdired--col-perm`).  Use `wdired--current-column`.
>     (wdired--point-at-perms-p): Fix when `wdired--perm-beg` is nil.
>     (wdired--self-insert): Lookup the keymap to know command to call.
>     (wdired--before-change-fn): Just use `point` instead of `beg`.
>     Use `with-silent-modifications` here rather than in each of the
>     `wdired--preprocess-*` functions.
>     (wdired--preprocess-files): Presume we're at BOL and within
>     `with-silent-modifications`.  Fix application of `read-only`.
>     (wdired-abort-changes): Don't use `with-silent-modifications` since
>     we're really modifying the buffer.
>     (wdired--preprocess-symlinks): Presume we're at BOL and within
>     `with-silent-modifications`.
>     (wdired--preprocess-perms): Presume we're at BOL and within
>     `with-silent-modifications`.
>     (wdired-set-bit): Add `char` argument.  Use `wdired--current-column`.
>     Copy previous text properties rather than duplicating the code of
>     `wdired--preprocess-perms`.
>     (wdired-toggle-bit): Delegate to `wdired-set-bit`.
>
> diff --git a/lisp/wdired.el b/lisp/wdired.el
> index 61272d947f..97861a4474 100644
> --- a/lisp/wdired.el
> +++ b/lisp/wdired.el
> @@ -189,7 +189,6 @@ wdired-mode-hook
>    "Hooks run when changing to WDired mode.")
>  
>  ;; Local variables (put here to avoid compilation gripes)
> -(defvar wdired--col-perm) ;; Column where the permission bits start
>  (defvar wdired--perm-beg) ;; Column where the permission bits start
>  (defvar wdired--perm-end) ;; Column where the permission bits stop
>  (defvar wdired--old-content)
> @@ -233,8 +232,6 @@ wdired-change-to-wdired-mode
>    (interactive)
>    (unless (derived-mode-p 'dired-mode)
>      (error "Not a Dired buffer"))
> -  (when (directory-empty-p (expand-file-name default-directory))
> -    (error "No files to be renamed"))
>    (setq-local wdired--old-content
>                (buffer-substring (point-min) (point-max)))
>    (setq-local wdired--old-marks
> @@ -264,49 +261,60 @@ wdired-change-to-wdired-mode
>  (defun wdired--set-permission-bounds ()
>    (save-excursion
>      (goto-char (point-min))
> -    (re-search-forward dired-re-perms nil t 1)
> -    (goto-char (match-beginning 0))
> -    (setq-local wdired--perm-beg (current-column))
> -    (goto-char (match-end 0))
> -    (setq-local wdired--perm-end (current-column))))
> +    (if (not (re-search-forward dired-re-perms nil t 1))
> +        (progn
> +          (setq-local wdired--perm-beg nil)
> +          (setq-local wdired--perm-end nil))
> +      (goto-char (match-beginning 0))
> +      ;; Add 1 since the first char matched by `dired-re-perms' is the
> +      ;; one describing the nature of the entry (dir/symlink/...) rather
> +      ;; than its permissions.
> +      (setq-local wdired--perm-beg (1+ (wdired--current-column)))
> +      (goto-char (match-end 0))
> +      (setq-local wdired--perm-end (wdired--current-column)))))
>  
>  (defun wdired--current-column ()
>    (- (point) (line-beginning-position)))
>  
>  (defun wdired--point-at-perms-p ()
> -  (<= wdired--perm-beg (wdired--current-column) wdired--perm-end))
> +  (and wdired--perm-beg
> +       (<= wdired--perm-beg (wdired--current-column) wdired--perm-end)))
>  
>  (defun wdired--line-preprocessed-p ()
>    (get-text-property (line-beginning-position) 'front-sticky))
>  
>  (defun wdired--self-insert ()
>    (interactive)
> -  (if (wdired--point-at-perms-p)
> -    (unless (wdired--line-preprocessed-p)
> -      (wdired--before-change-fn (line-beginning-position) (line-end-position))
> -      (wdired-toggle-bit))
> -    (call-interactively 'self-insert-command)))
> +  (if (wdired--line-preprocessed-p)
> +      (call-interactively 'self-insert-command)
> +    (wdired--before-change-fn (line-beginning-position) (line-end-position))
> +    (let ((map (get-text-property (point) 'keymap)))
> +      (when map
> +        (let ((cmd (lookup-key map (this-command-keys))))
> +          (call-interactively (or cmd 'self-insert-command)))))))
>  
>  (defun wdired--before-change-fn (beg end)
>    (save-excursion
> -    ;; make sure to process entire lines
> -    (goto-char beg)
> -    (setq beg (line-beginning-position))
> +    ;; Make sure to process entire lines.
>      (goto-char end)
>      (setq end (line-end-position))
> +    (goto-char beg)
> +    (forward-line 0)
>  
> -    (while (< beg end)
> +    (while (< (point) end)
>        (unless (wdired--line-preprocessed-p)
> -        (put-text-property beg (1+ beg) 'front-sticky t)
> -        (wdired--preprocess-files)
> -        (when wdired-allow-to-change-permissions
> -          (wdired--preprocess-perms))
> -        (when (fboundp 'make-symbolic-link)
> -          (wdired--preprocess-symlinks)))
> -      (forward-line)
> -      (setq beg (point)))
> -    ;; is this good enough? assumes no extra white lines from dired
> -    (put-text-property (1- (point-max)) (point-max) 'read-only t)))
> +        (with-silent-modifications
> +          (put-text-property (point) (1+ (point)) 'front-sticky t)
> +          (wdired--preprocess-files)
> +          (when wdired-allow-to-change-permissions
> +            (wdired--preprocess-perms))
> +          (when (fboundp 'make-symbolic-link)
> +            (wdired--preprocess-symlinks))))
> +      (forward-line))
> +    (when (eobp)
> +      (with-silent-modifications
> +        ;; Is this good enough? Assumes no extra white lines from dired.
> +        (put-text-property (1- (point-max)) (point-max) 'read-only t)))))
>  
>  (defun wdired-isearch-filter-read-only (beg end)
>    "Skip matches that have a read-only property."
> @@ -317,28 +325,26 @@ wdired-isearch-filter-read-only
>  ;; properties so filenames (old and new) can be easily found.
>  (defun wdired--preprocess-files ()
>    (save-excursion
> -    (with-silent-modifications
> -      (beginning-of-line)
> -      (let ((used-F (dired-check-switches dired-actual-switches "F" "classify"))
> -	    filename)
> -	(setq filename (dired-get-filename nil t))
> -        (when (and filename
> -		   (not (member (file-name-nondirectory filename) '("." ".."))))
> -	  (dired-move-to-filename)
> -	  ;; The rear-nonsticky property below shall ensure that text preceding
> -	  ;; the filename can't be modified.
> -	  (add-text-properties
> -	   (1- (point)) (point) `(old-name ,filename rear-nonsticky (read-only)))
> -	  (put-text-property (- (point) 1) (point) 'read-only t)
> -          (dired-move-to-end-of-filename t)
> -	  (put-text-property (point) (1+ (point)) 'end-name t))
> -        (when (and used-F (looking-at "[*/@|=>]$")) (forward-char))
> -        (when (save-excursion
> -                (and (re-search-backward
> -                      dired-permission-flags-regexp nil t)
> -                     (looking-at "l")
> -                     (search-forward " -> " (line-end-position) t)))
> -          (goto-char (line-end-position)))))))
> +    (let ((used-F (dired-check-switches dired-actual-switches "F" "classify"))
> +	  (beg (point))
> +          (filename (dired-get-filename nil t)))
> +      (when (and filename
> +		 (not (member (file-name-nondirectory filename) '("." ".."))))
> +	(dired-move-to-filename)
> +	;; The rear-nonsticky property below shall ensure that text preceding
> +	;; the filename can't be modified.
> +	(add-text-properties
> +	 (1- (point)) (point) `(old-name ,filename rear-nonsticky (read-only)))
> +	(put-text-property beg (point) 'read-only t)
> +        (dired-move-to-end-of-filename t)
> +	(put-text-property (point) (1+ (point)) 'end-name t))
> +      (when (and used-F (looking-at "[*/@|=>]$")) (forward-char))
> +      (when (save-excursion
> +              (and (re-search-backward
> +                    dired-permission-flags-regexp nil t)
> +                   (looking-at "l")
> +                   (search-forward " -> " (line-end-position) t)))
> +        (goto-char (line-end-position))))))
>  
>  ;; This code is a copy of some dired-get-filename lines.
>  (defsubst wdired-normalize-filename (file unquotep)
> @@ -425,8 +431,8 @@ wdired-change-to-dired-mode
>  (defun wdired-abort-changes ()
>    "Abort changes and return to dired mode."
>    (interactive)
> -  (remove-hook 'before-change-functions 'wdired--before-change-fn t)
> -  (with-silent-modifications
> +  (remove-hook 'before-change-functions #'wdired--before-change-fn t)
> +  (let ((inhibit-read-only t))
>      (erase-buffer)
>      (insert wdired--old-content)
>      (goto-char wdired--old-point))
> @@ -451,7 +457,7 @@ wdired-finish-edit
>  	(setq errors (cdr tmp-value))
>  	(setq changes (car tmp-value)))
>        (when (and wdired-allow-to-change-permissions
> -		 (boundp 'wdired--col-perm)) ; could have been changed
> +		 wdired--perm-beg) ; could have been changed
>  	(setq tmp-value (wdired-do-perm-changes))
>  	(setq errors (+ errors (cdr tmp-value)))
>  	(setq changes (or changes (car tmp-value))))
> @@ -744,17 +750,15 @@ wdired-previous-line
>  ;; Put the needed properties to allow the user to change links' targets
>  (defun wdired--preprocess-symlinks ()
>    (save-excursion
> -    (with-silent-modifications
> -      (beginning-of-line)
> -      (when (looking-at dired-re-sym)
> -        (re-search-forward " -> \\(.*\\)$")
> -	(put-text-property (1- (match-beginning 1))
> -			   (match-beginning 1) 'old-link
> -			   (match-string-no-properties 1))
> -        (put-text-property (match-end 1) (1+ (match-end 1)) 'end-link t)
> -        (unless wdired-allow-to-redirect-links
> -          (put-text-property (match-beginning 0)
> -			     (match-end 1) 'read-only t))))))
> +    (when (looking-at dired-re-sym)
> +      (re-search-forward " -> \\(.*\\)$")
> +      (put-text-property (1- (match-beginning 1))
> +			 (match-beginning 1) 'old-link
> +			 (match-string-no-properties 1))
> +      (put-text-property (match-end 1) (1+ (match-end 1)) 'end-link t)
> +      (unless wdired-allow-to-redirect-links
> +        (put-text-property (match-beginning 0)
> +			   (match-end 1) 'read-only t)))))
>  
>  (defun wdired-get-previous-link (&optional old move)
>    "Return the next symlink target.
> @@ -861,31 +865,26 @@ wdired-perm-mode-map
>  ;; original name and permissions as a property
>  (defun wdired--preprocess-perms ()
>    (save-excursion
> -    (with-silent-modifications
> -      (setq-local wdired--col-perm nil)
> -      (beginning-of-line)
> -      (when (and (not (looking-at dired-re-sym))
> -		 (wdired-get-filename)
> -		 (re-search-forward dired-re-perms
> -                                    (line-end-position) 'eol))
> -	(let ((begin (match-beginning 0))
> -	      (end (match-end 0)))
> -	  (unless wdired--col-perm
> -	    (setq wdired--col-perm (- (current-column) 9)))
> -	  (if (eq wdired-allow-to-change-permissions 'advanced)
> -	      (progn
> -		(put-text-property begin end 'read-only nil)
> -		;; make first permission bit writable
> -		(put-text-property
> -		 (1- begin) begin 'rear-nonsticky '(read-only)))
> -	    ;; avoid that keymap applies to text following permissions
> -	    (add-text-properties
> -	     (1+ begin) end
> -	     `(keymap ,wdired-perm-mode-map rear-nonsticky (keymap))))
> -	  (put-text-property end (1+ end) 'end-perm t)
> -	  (put-text-property
> -	   begin (1+ begin)
> -           'old-perm (match-string-no-properties 0)))))))
> +    (when (and (not (looking-at dired-re-sym))
> +	       (wdired-get-filename)
> +	       (re-search-forward dired-re-perms
> +                                  (line-end-position) 'eol))
> +      (let ((begin (match-beginning 0))
> +	    (end (match-end 0)))
> +	(if (eq wdired-allow-to-change-permissions 'advanced)
> +	    (progn
> +	      (put-text-property begin end 'read-only nil)
> +	      ;; make first permission bit writable
> +	      (put-text-property
> +	       (1- begin) begin 'rear-nonsticky '(read-only)))
> +	  ;; avoid that keymap applies to text following permissions
> +	  (add-text-properties
> +	   (1+ begin) end
> +	   `(keymap ,wdired-perm-mode-map rear-nonsticky (keymap))))
> +	(put-text-property end (1+ end) 'end-perm t)
> +	(put-text-property
> +	 begin (1+ begin)
> +         'old-perm (match-string-no-properties 0))))))
>  
>  (defun wdired-perm-allowed-in-pos (char pos)
>    (cond
> @@ -897,39 +896,30 @@ wdired-perm-allowed-in-pos
>     ((memq char '(?t ?T)) (= pos 8))
>     ((= char ?l)          (= pos 5))))
>  
> -(defun wdired-set-bit ()
> +(defun wdired-set-bit (&optional char)
>    "Set a permission bit character."
> -  (interactive)
> -  (if (wdired-perm-allowed-in-pos last-command-event
> -                                  (- (current-column) wdired--col-perm))
> -      (let ((new-bit (char-to-string last-command-event))
> +  (interactive (list last-command-event))
> +  (unless char (setq char last-command-event))
> +  (if (wdired-perm-allowed-in-pos char
> +                                  (- (wdired--current-column) wdired--perm-beg))
> +      (let ((new-bit (char-to-string char))
>              (inhibit-read-only t)
> -	    (pos-prop (- (point) (- (current-column) wdired--col-perm))))
> -        (put-text-property 0 1 'keymap wdired-perm-mode-map new-bit)
> -        (put-text-property 0 1 'read-only t new-bit)
> +	    (pos-prop (+ (line-beginning-position) wdired--perm-beg)))
> +        (set-text-properties 0 1 (text-properties-at (point)) new-bit)
>          (insert new-bit)
>          (delete-char 1)
> -	(put-text-property (1- pos-prop) pos-prop 'perm-changed t)
> -	(put-text-property (1- (point)) (point) 'rear-nonsticky '(keymap)))
> +	(put-text-property (1- pos-prop) pos-prop 'perm-changed t))
>      (forward-char 1)))
>  
>  (defun wdired-toggle-bit ()
>    "Toggle the permission bit at point."
>    (interactive)
> -  (let ((inhibit-read-only t)
> -	(new-bit "-")
> -	(pos-prop (- (point) (- (current-column) wdired--col-perm))))
> -    (if (eq (char-after (point)) ?-)
> -	(setq new-bit
> -	      (if (= (% (- (current-column) wdired--col-perm) 3) 0) "r"
> -		(if (= (% (- (current-column) wdired--col-perm) 3) 1) "w"
> -		  "x"))))
> -    (put-text-property 0 1 'keymap wdired-perm-mode-map new-bit)
> -    (put-text-property 0 1 'read-only t new-bit)
> -    (insert new-bit)
> -    (delete-char 1)
> -    (put-text-property (1- pos-prop) pos-prop 'perm-changed t)
> -    (put-text-property (1- (point)) (point) 'rear-nonsticky '(keymap))))
> +  (wdired-set-bit
> +   (cond
> +    ((not (eq (char-after (point)) ?-)) ?-)
> +    ((= (% (- (wdired--current-column) wdired--perm-beg) 3) 0) ?r)
> +    ((= (% (- (wdired--current-column) wdired--perm-beg) 3) 1) ?w)
> +    (t ?x))))
>  
>  (defun wdired-mouse-toggle-bit (event)
>    "Toggle the permission bit that was left clicked."