From f4d7ca73e3ab975fd920a2b0f2d1a7fdb5276d99 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sun, 5 Dec 2021 18:35:27 -0800 Subject: [PATCH] Simplify message-unique-id etc. * lisp/gnus/message.el (message-unique-id): * lisp/net/sasl.el (sasl-unique-id-function): Avoid unnecessary consing and reliance on internal timestamp format by using (time-convert nil 'integer) which typically does no consing, instead of using (current-time) and then ignoring the subsecond parts of the generated list. --- lisp/gnus/message.el | 24 +++++++++++++----------- lisp/net/sasl.el | 23 +++++++++++++---------- 2 files changed, 26 insertions(+), 21 deletions(-) diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el index 562bc64f6fb..8e7983a33c3 100644 --- a/lisp/gnus/message.el +++ b/lisp/gnus/message.el @@ -5828,15 +5828,15 @@ In posting styles use `(\"Expires\" (make-expires-date 30))'." ;; You might for example insert a "." somewhere (not next to another dot ;; or string boundary), or modify the "fsf" string. (defun message-unique-id () - ;; Don't use microseconds from (current-time), they may be unsupported. + ;; Don't use fractional seconds from timestamp; they may be unsupported. ;; Instead we use this randomly inited counter. (setq message-unique-id-char - (% (1+ (or message-unique-id-char - (random (ash 1 20)))) - ;; (current-time) returns 16-bit ints, - ;; and 2^16*25 just fits into 4 digits i base 36. - (* 25 25))) - (let ((tm (current-time))) + ;; 2^16 * 25 just fits into 4 digits i base 36. + (let ((base (* 25 25))) + (if message-unique-id-char + (% (1+ message-unique-id-char) base) + (random base)))) + (let ((tm (time-convert nil 'integer))) (concat (if (or (eq system-type 'ms-dos) ;; message-number-base36 doesn't handle bigints. @@ -5846,10 +5846,12 @@ In posting styles use `(\"Expires\" (make-expires-date 30))'." (aset user (match-beginning 0) ?_)) user) (message-number-base36 (user-uid) -1)) - (message-number-base36 (+ (car tm) - (ash (% message-unique-id-char 25) 16)) 4) - (message-number-base36 (+ (nth 1 tm) - (ash (/ message-unique-id-char 25) 16)) 4) + (message-number-base36 (+ (ash tm -16) + (ash (% message-unique-id-char 25) 16)) + 4) + (message-number-base36 (+ (logand tm #xffff) + (ash (/ message-unique-id-char 25) 16)) + 4) ;; Append a given name, because while the generated ID is unique ;; to this newsreader, other newsreaders might otherwise generate ;; the same ID via another algorithm. diff --git a/lisp/net/sasl.el b/lisp/net/sasl.el index b7f814f7237..0a3ecf9f534 100644 --- a/lisp/net/sasl.el +++ b/lisp/net/sasl.el @@ -174,21 +174,24 @@ It contain at least 64 bits of entropy." ;; stolen (and renamed) from message.el (defun sasl-unique-id-function () - ;; Don't use microseconds from (current-time), they may be unsupported. + ;; Don't use fractional seconds from timestamp; they may be unsupported. ;; Instead we use this randomly inited counter. (setq sasl-unique-id-char - (% (1+ (or sasl-unique-id-char (logand (random) (1- (ash 1 20))))) - ;; (current-time) returns 16-bit ints, - ;; and 2^16*25 just fits into 4 digits i base 36. - (* 25 25))) - (let ((tm (current-time))) + ;; 2^16 * 25 just fits into 4 digits i base 36. + (let ((base (* 25 25))) + (if sasl-unique-id-char + (% (1+ sasl-unique-id-char) base) + (random base)))) + (let ((tm (time-convert nil 'integer))) (concat (sasl-unique-id-number-base36 - (+ (car tm) - (ash (% sasl-unique-id-char 25) 16)) 4) + (+ (ash tm -16) + (ash (% sasl-unique-id-char 25) 16)) + 4) (sasl-unique-id-number-base36 - (+ (nth 1 tm) - (ash (/ sasl-unique-id-char 25) 16)) 4)))) + (+ (logand tm #xffff) + (ash (/ sasl-unique-id-char 25) 16)) + 4)))) (defun sasl-unique-id-number-base36 (num len) (if (if (< len 0) -- 2.39.2