(put symbol 'abortfunc (or abortfunc 'kill-buffer))
(put symbol 'hookvar (or hookvar 'mail-send-hook)))
+;; Standardized progress reporting
+
+;; Progress reporter has the following structure:
+;;
+;; (NEXT-UPDATE-VALUE . [NEXT-UPDATE-TIME
+;; MIN-VALUE
+;; MAX-VALUE
+;; MESSAGE
+;; MIN-CHANGE
+;; MIN-TIME])
+;;
+;; This weirdeness is for optimization reasons: we want
+;; `progress-reporter-update' to be as fast as possible, so
+;; `(car reporter)' is better than `(aref reporter 0)'.
+;;
+;; NEXT-UPDATE-TIME is a float. While `float-time' loses a couple
+;; digits of precision, it doesn't really matter here. On the other
+;; hand, it greatly simplifies the code.
+
+(defun make-progress-reporter (message min-value max-value
+ &optional current-value
+ min-change min-time)
+ "Return an object suitable for reporting operation progress with `progress-reporter-update'.
+
+MESSAGE is shown in the echo area. When at least 1% of operation
+is complete, the exact percentage will be appended to the
+MESSAGE. When you call `progress-reporter-done', word \"done\"
+is printed after the MESSAGE. You can change MESSAGE of an
+existing progress reporter with `progress-reporter-force-update'.
+
+MIN-VALUE and MAX-VALUE designate starting (0% complete) and
+final (100% complete) states of operation. The latter should be
+larger; if this is not the case, then simply negate all values.
+Optional CURRENT-VALUE specifies the progress by the moment you
+call this function. You should omit it or set it to nil in most
+cases since it defaults to MIN-VALUE.
+
+Optional MIN-CHANGE determines the minimal change in percents to
+report (default is 1%.) Optional MIN-TIME specifies the minimal
+time before echo area updates (default is 0.2 seconds.) If
+`float-time' function is not present, then time is not tracked
+at all. If OS is not capable of measuring fractions of seconds,
+then this parameter is effectively rounded up."
+
+ (unless min-time
+ (setq min-time 0.2))
+ (let ((reporter
+ (cons min-value ;; Force a call to `message' now
+ (vector (if (and (fboundp 'float-time)
+ (>= min-time 0.02))
+ (float-time) nil)
+ min-value
+ max-value
+ message
+ (if min-change (max (min min-change 50) 1) 1)
+ min-time))))
+ (progress-reporter-update reporter (or current-value min-value))
+ reporter))
+
+(defsubst progress-reporter-update (reporter value)
+ "Report progress of an operation in the echo area.
+However, if the change since last echo area update is too small
+or not enough time has passed, then do nothing (see
+`make-progress-reporter' for details).
+
+First parameter, REPORTER, should be the result of a call to
+`make-progress-reporter'. Second, VALUE, determines the actual
+progress of operation; it must be between MIN-VALUE and MAX-VALUE
+as passed to `make-progress-reporter'.
+
+This function is very inexpensive, you may not bother how often
+you call it."
+ (when (>= value (car reporter))
+ (progress-reporter-do-update reporter value)))
+
+(defun progress-reporter-force-update (reporter value &optional new-message)
+ "Report progress of an operation in the echo area unconditionally.
+
+First two parameters are the same as for
+`progress-reporter-update'. Optional NEW-MESSAGE allows you to
+change the displayed message."
+ (let ((parameters (cdr reporter)))
+ (when new-message
+ (aset parameters 3 new-message))
+ (when (aref parameters 0)
+ (aset parameters 0 (float-time)))
+ (progress-reporter-do-update reporter value)))
+
+(defun progress-reporter-do-update (reporter value)
+ (let* ((parameters (cdr reporter))
+ (min-value (aref parameters 1))
+ (max-value (aref parameters 2))
+ (one-percent (/ (- max-value min-value) 100.0))
+ (percentage (truncate (/ (- value min-value) one-percent)))
+ (update-time (aref parameters 0))
+ (current-time (float-time))
+ (enough-time-passed
+ ;; See if enough time has passed since the last update.
+ (or (not update-time)
+ (when (>= current-time update-time)
+ ;; Calculate time for the next update
+ (aset parameters 0 (+ update-time (aref parameters 5)))))))
+ ;;
+ ;; Calculate NEXT-UPDATE-VALUE. If we are not going to print
+ ;; message this time because not enough time has passed, then use
+ ;; 1 instead of MIN-CHANGE. This makes delays between echo area
+ ;; updates closer to MIN-TIME.
+ (setcar reporter
+ (min (+ min-value (* (+ percentage
+ (if enough-time-passed
+ (aref parameters 4) ;; MIN-CHANGE
+ 1))
+ one-percent))
+ max-value))
+ (when (integerp value)
+ (setcar reporter (ceiling (car reporter))))
+ ;;
+ ;; Only print message if enough time has passed
+ (when enough-time-passed
+ (if (> percentage 0)
+ (message "%s%d%%" (aref parameters 3) percentage)
+ (message "%s" (aref parameters 3))))))
+
+(defun progress-reporter-done (reporter)
+ "Print reporter's message followed by word \"done\" in echo area."
+ (message "%sdone" (aref (cdr reporter) 3)))
+
;; arch-tag: f7e0e6e5-70aa-4897-ae72-7a3511ec40bc
;;; subr.el ends here