bug#13831: 24.3.50; [PATCH] net-utils-mode have no revert-buffer function

[Thierry Volpiatto <thierry.volpiatto@gmail.com>]

Hi Stefan,

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

>> Indeed yes, tried this very early this morning.
>> Just tried now and it is working,
>
> Thanks.
>
>> but point move at eof, it should stay on top of buffer.
>
> I think the difference between the initial run and the revert is that
> for the initial run, the traceroute buffer is not in the
> selected-window, whereas in the revert case, it is the selected-window.
>
> Apparently the behavior is partly on purpose, since
> net-utils-remove-ctrl-m-filter (which, BTW, should use
> with-current-buffer rather than unwind-protect) explicitly moves point.

Here your patch modified, I have simplified
`net-utils-remove-ctrl-m-filter'.

diff --git a/lisp/net/net-utils.el b/lisp/net/net-utils.el
index 28fd5c6..5fe8d35 100644
--- a/lisp/net/net-utils.el
+++ b/lisp/net/net-utils.el
@@ -285,7 +285,8 @@ This variable is only used if the variable
 (define-derived-mode net-utils-mode special-mode "NetworkUtil"
   "Major mode for interacting with an external network utility."
   (set (make-local-variable 'font-lock-defaults)
-       '((net-utils-font-lock-keywords))))
+       '((net-utils-font-lock-keywords)))
+  (setq-local revert-buffer-function #'net-utils--revert-function))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Utility functions
@@ -318,25 +319,18 @@ This variable is only used if the variable
 
 (defun net-utils-remove-ctrl-m-filter (process output-string)
   "Remove trailing control Ms."
-  (let ((old-buffer (current-buffer))
-	(filtered-string output-string))
-    (unwind-protect
-	(let ((moving))
-	  (set-buffer (process-buffer process))
-	  (let ((inhibit-read-only t))
-	    (setq moving (= (point) (process-mark process)))
-
-	    (while (string-match "\r" filtered-string)
-	      (setq filtered-string
-		    (replace-match "" nil nil filtered-string)))
-
-	    (save-excursion
-	      ;; Insert the text, moving the process-marker.
-	      (goto-char (process-mark process))
-	      (insert filtered-string)
-	      (set-marker (process-mark process) (point))))
-	  (if moving (goto-char (process-mark process))))
-      (set-buffer old-buffer))))
+  (save-selected-window
+    (set-buffer (process-buffer process))
+    (save-excursion
+      (let ((inhibit-read-only t)
+            (filtered-string output-string))
+        (while (string-match "\r" filtered-string)
+          (setq filtered-string
+                (replace-match "" nil nil filtered-string)))
+        ;; Insert the text, moving the process-marker.
+        (goto-char (process-mark process))
+        (insert filtered-string)
+        (set-marker (process-mark process) (point))))))
 
 (defun net-utils-run-program (name header program args)
   "Run a network information program."
@@ -354,20 +348,38 @@ This variable is only used if the variable
 ;; General network utilities (diagnostic)
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(defun net-utils-run-simple (buffer-name program-name args)
+;; Todo: This data could be saved in a bookmark.
+(defvar net-utils--revert-cmd nil)
+
+(defun net-utils-run-simple (buffer program-name args)
   "Run a network utility for diagnostic output only."
-  (interactive)
-  (when (get-buffer buffer-name)
-    (kill-buffer buffer-name))
-  (get-buffer-create buffer-name)
-  (with-current-buffer buffer-name
+  (with-current-buffer (if (stringp buffer) (get-buffer-create buffer) buffer)
+    (let ((proc (get-buffer-process (current-buffer))))
+      (when proc
+        (set-process-filter proc nil)
+        (delete-process proc)))
+    (let ((inhibit-read-only t))
+      (erase-buffer))
     (net-utils-mode)
+    (setq-local net-utils--revert-cmd
+                `(net-utils-run-simple ,(current-buffer) ,program-name ,args))
     (set-process-filter
-     (apply 'start-process (format "%s" program-name)
-	    buffer-name program-name args)
+         (apply 'start-process program-name
+                (current-buffer) program-name args)
      'net-utils-remove-ctrl-m-filter)
-    (goto-char (point-min)))
-  (display-buffer buffer-name))
+    (goto-char (point-min))
+    (display-buffer (current-buffer))))
+
+(defun net-utils--revert-function (&optional ignore-auto noconfirm)
+  (message "Reverting `%s'..." (buffer-name))
+  (apply (car net-utils--revert-cmd) (cdr net-utils--revert-cmd))
+  (let ((proc (get-buffer-process (current-buffer))))
+    (when proc
+      (set-process-sentinel
+       proc
+       (lambda (process event)
+         (when (string= event "finished\n")
+           (message "Reverting `%s' done" (process-buffer process))))))))
 
 ;;;###autoload
 (defun ifconfig ()
@@ -428,9 +440,8 @@ This variable is only used if the variable
 	 (if traceroute-program-options
 	     (append traceroute-program-options (list target))
 	   (list target))))
-    (net-utils-run-program
+    (net-utils-run-simple
      (concat "Traceroute" " " target)
-     (concat "** Traceroute ** " traceroute-program " ** " target)
      traceroute-program
      options)))
 
 
-- 
Thierry
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