Re: [PATCH] `org-clock--oldest-date` performance

[Jack Henahan <jhenahan@me.com>]

[-- Attachment #1: Type: text/plain, Size: 1713 bytes --]

I wasn't altogether certain that it could never be nil, and my eyes seem
to have skipped over the expression you called out so I missed that case
in my testing. I have reworked the patch as you suggest. Now the
behavior should be entirely unchanged except in the `untilnow' case
where we use the new date, no extra nils.

Revised patch attached.

Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

> Hello,
>
> Jack Henahan <jhenahan@me.com> writes:
>
>> Functionally, this means that today `org-clock-special-range` produces a
>> range from the current time until the current time if `start` ends up
>> nil for whatever reason
>
> That's not true. Currently, `org-clock-special-range' never returns
> a nil start time. This is where I don't understand your patch:
>
>> -		    (`untilnow org-clock--oldest-date)
>> +		    (`untilnow nil)
>>  		    (_ (encode-time 0 m h d month y))))
>>  	   (end (pcase key
>>  		  (`interactive (org-read-date nil t nil "Range end? "))
>> @@ -2283,8 +2251,12 @@ have priority."
>>  	      (`interactive "(Range interactively set)")
>>  	      (`untilnow "now"))))
>>        (if (not as-strings) (list start end text)
>                                     ^^^^^
>                               this can now be nil
>> -	(let ((f (cdr org-time-stamp-formats)))
>> -	  (list (format-time-string f start)
>> +	(let ((f (cdr org-time-stamp-formats))
>> +              (safe-start
>> +	       (if (not start)
>> +		   (encode-time 0 0 0 0 0 -50000)
>> +		 start)))
>> +	  (list (format-time-string f safe-start)
>>  		(format-time-string f end)
>>  		text))))))
>
> Why not replacing `org-clock--oldest-date' with (encode-time
> 0 0 0 0 0 -50000) in the let binding above?
>
> Regards,

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-org-clock.el-Improve-untilnow-range-behavior-and.patch --]
[-- Type: text/x-patch, Size: 3007 bytes --]

From a0792b3900812b6a2385794f30ba7c057bc9fcf7 Mon Sep 17 00:00:00 2001
From: Jack Henahan <jhenahan@me.com>
Date: Sun, 21 Jan 2018 10:40:22 -0500
Subject: [PATCH] org-clock.el: Improve `untilnow' range behavior and 
 performance

* org-clock.el:
(org-clock-special-range): Set `untilnow' to use the year -50000,
rather than the earliest representable date.
(org-clock--oldest-date): Remove.

The `untilnow' range relied on the constant `org-clock--oldest-date`
to find the earliest representable date, which caused delays when
loading `org-clock' on systems where `most-negative-fixnum' is large.
This change removes that constant in favor of a simpler hack to
produce a range between the current time and before the dawn of human
civilization. If this breaks your workflow, please report to the Time
Police.
---
 lisp/org-clock.el | 35 ++---------------------------------
 1 file changed, 2 insertions(+), 33 deletions(-)

diff --git a/lisp/org-clock.el b/lisp/org-clock.el
index 496c4310a..d580ffa43 100644
--- a/lisp/org-clock.el
+++ b/lisp/org-clock.el
@@ -468,38 +468,6 @@ to add an effort property.")
 (defvar org-clock-stored-resume-clock nil
   "Clock to resume, saved by `org-clock-load'")
 
-(defconst org-clock--oldest-date
-  (let* ((dichotomy
-	  (lambda (min max pred)
-	    (if (funcall pred min) min
-	      (cl-incf min)
-	      (while (> (- max min) 1)
-		(let ((mean (+ (ash min -1) (ash max -1) (logand min max 1))))
-		  (if (funcall pred mean) (setq max mean) (setq min mean)))))
-	    max))
-	 (high
-	  (funcall dichotomy
-		   most-negative-fixnum
-		   0
-		   (lambda (m)
-                     ;; libc in macOS 10.6 hangs when decoding times
-                     ;; around year -2**31.  Limit `high' not to go
-                     ;; any earlier than that.
-                     (unless (and (eq system-type 'darwin)
-                                  (string-match-p
-                                   "10\\.6\\.[[:digit:]]"
-                                   (shell-command-to-string
-                                    "sw_vers -productVersion"))
-                                  (<= m -1034058203135))
-                       (ignore-errors (decode-time (list m 0)))))))
-	 (low
-	  (funcall dichotomy
-		   most-negative-fixnum
-		   0
-		   (lambda (m) (ignore-errors (decode-time (list high m)))))))
-    (list high low))
-  "Internal time for oldest date representable on the system.")
-
 ;;; The clock for measuring work time.
 
 (defvar org-mode-line-string "")
@@ -2260,7 +2228,8 @@ have priority."
     ;; Format start and end times according to AS-STRINGS.
     (let* ((start (pcase key
 		    (`interactive (org-read-date nil t nil "Range start? "))
-		    (`untilnow org-clock--oldest-date)
+                    ;; In theory, all clocks started after the dawn of humanity
+		    (`untilnow (encode-time 0 0 0 0 0 -50000))
 		    (_ (encode-time 0 m h d month y))))
 	   (end (pcase key
 		  (`interactive (org-read-date nil t nil "Range end? "))
-- 
2.15.1