bug#65251: 30.0.50; Duration in compilation buffer

[Helmut Eller]

On Thu, Aug 17 2023, Eli Zaretskii wrote:

> I intended to install this once there are no more review comments, as
> I think this could be a useful addition.  I believe Mattias also
> thought the idea was a good one.  So my preference is for you to post
> an updated patch, yes.

Here it is:

>From 3f41a75a61a08c1e2850bf3e3e4d1d2d137aeedd Mon Sep 17 00:00:00 2001
From: Helmut Eller <eller.helmut@gmail.com>
Date: Thu, 17 Aug 2023 20:46:05 +0200
Subject: [PATCH] When a compilation finishes, show how long it took

Insert the duration, not just the timestamp.

* lisp/progmodes/compile.el (compilation--start-time): New variable.
(compilation-start): Set it.
(compilation-handle-exit): Use it to compute the duration and insert
it in human readable form.
---
 lisp/progmodes/compile.el | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lisp/progmodes/compile.el b/lisp/progmodes/compile.el
index 6d151db8a83..a41fca7de1e 100644
--- a/lisp/progmodes/compile.el
+++ b/lisp/progmodes/compile.el
@@ -1862,6 +1862,9 @@ compilation-insert-annotation
     (apply #'insert args)
     (put-text-property start (point) 'compilation-annotation t)))
 
+;; The time when the compilation started as returned by `float-time'.
+(defvar-local compilation--start-time nil)
+
 ;;;###autoload
 (defun compilation-start (command &optional mode name-function highlight-regexp
                                   continue)
@@ -1993,6 +1996,7 @@ compilation-start
                  mode-name
                 (substring (current-time-string) 0 19))
         command "\n")
+        (setq compilation--start-time (float-time))
        (setq thisdir default-directory))
       (set-buffer-modified-p nil))
     ;; Pop up the compilation buffer.
@@ -2480,7 +2484,14 @@ compilation-handle-exit
        (message "%s" (cdr status)))
     (if (bolp)
        (forward-char -1))
-    (compilation-insert-annotation " at " (substring (current-time-string) 0 
19))
+    (compilation-insert-annotation
+     " at "
+     (substring (current-time-string) 0 19)
+     ", duration "
+     (let* ((secs (- (float-time) compilation--start-time)))
+       (cond ((< secs 10) (format "%.2f s" secs))
+            ((< secs 60) (format "%.1f s" secs))
+            (t (format-seconds "%h:%m:%s" secs)))))
     (goto-char (point-max))
     ;; Prevent that message from being recognized as a compilation error.
     (add-text-properties omax (point)
-- 
2.39.2