Megatest

	 (currtime (current-seconds)))
    (if (> (- currtime lasttime) waitval)
	(begin
	  (hash-table-set! *common:denoise* key currtime)
	  #t)
	#f)))

;; environment vars handy stuff from common.scm
;;
(define getenv get-environment-variable)
(define (safe-setenv key val)
  (if (or (substring-index "!" key)
	  (substring-index ":" key)  ;; variables containing : are for internal use and cannot be environment variables.
	  (substring-index "." key)) ;; periods are not allowed in environment variables
      (debug:print-error 4 *default-log-port* "skip setting internal use only variables containing \":\" or starting with \"!\"")
      (if (and (string? val)
	       (string? key))
	  (handle-exceptions
	      exn
	      (debug:print-error 0 *default-log-port* "bad value for setenv, key=" key ", value=" val ", exn=" exn)
	    (setenv key val))
	  (debug:print-error 0 *default-log-port* "bad value for setenv, key=" key ", value=" val))))

;;======================================================================
;; accept an alist or hash table containing envvar/env value pairs (value of #f causes unset) 
;;   execute thunk in context of environment modified as per this list
;;   restore env to prior state then return value of eval'd thunk.
;;   ** this is not thread safe **
(define (common:with-env-vars delta-env-alist-or-hash-table thunk)
  (let* ((delta-env-alist (if (hash-table? delta-env-alist-or-hash-table)
                              (hash-table->alist delta-env-alist-or-hash-table)
                              delta-env-alist-or-hash-table))
         (restore-thunks
          (filter
           identity
           (map (lambda (env-pair)
                  (let* ((env-var     (car env-pair))
                         (new-val     (let ((tmp (cdr env-pair)))
                                        (if (list? tmp) (car tmp) tmp)))
                         (current-val (get-environment-variable env-var))
                         (restore-thunk
                          (cond
                           ((not current-val) (lambda () (unsetenv env-var)))
                           ((not (string? new-val)) #f)
                           ((eq? current-val new-val) #f)
                           (else 
                            (lambda () (setenv env-var current-val))))))
                    ;;(when (not (string? new-val))
                    ;;    (debug:print 0 *default-log-port* " PROBLEM: not a string: "new-val"\n from env-alist:\n"delta-env-alist)
                    ;;    (pp delta-env-alist)
                    ;;    (exit 1))
                        
                    
                    (cond
                     ((not new-val)  ;; modify env here
                      (unsetenv env-var))
                     ((string? new-val)
                      (setenv env-var new-val)))
                    restore-thunk))
                delta-env-alist))))
    (let ((rv (thunk)))
      (for-each (lambda (x) (x)) restore-thunks) ;; restore env to original state
      rv)))

(define home (getenv "HOME"))
(define user (getenv "USER"))

;;======================================================================
;; return a nice clean pathname made absolute
(define (common:nice-path dir)
  (let ((match (string-match "^(~[^\\/]*)(\\/.*|)$" dir)))
    (if match ;; using ~ for home?
	(common:nice-path (conc (common:read-link-f (cadr match)) "/" (caddr match)))
	(normalize-pathname (if (absolute-pathname? dir)
				dir
				(conc (current-directory) "/" dir))))))

(define (common:read-link-f path)
  (handle-exceptions
      exn
      (begin
	(debug:print-error 0 *default-log-port* "command \"/bin/readlink -f " path "\" failed. exn=" exn)
	path) ;; just give up
    (with-input-from-pipe
	(conc "/bin/readlink -f " path)
      (lambda ()
	(read-line)))))

;; for reasons I don't understand multiple calls to real-path in parallel threads
;; must be protected by mutexes
;;
(define (common:real-path inpath)
  ;; (process:cmd-run-with-stderr->list "readlink" "-f" inpath)) ;; cmd . params)
  ;; (let-values 
  ;;  (((inp oup pid) (process "readlink" (list "-f" inpath))))
  ;;  (with-input-from-port inp
  ;;    (let loop ((inl (read-line))
  ;;       	(res #f))
  ;;      (print "inl=" inl)
  ;;      (if (eof-object? inl)
  ;;          (begin
  ;;            (close-input-port inp)
  ;;            (close-output-port oup)
  ;;            ;; (process-wait pid)
  ;;            res)
  ;;          (loop (read-line) inl))))))
  (with-input-from-pipe (conc "readlink -f " inpath) read-line))

;; KEEP THIS ONE
;;
;; client:get-signature

(define *my-client-signature* #f)

(define (client:get-signature)
  (if *my-client-signature* *my-client-signature*
      (let ((sig (conc (get-host-name) " " (current-process-id))))
	(set! *my-client-signature* sig)
	*my-client-signature*)))

(define *server-info* #f)
(define *toppath* #f)

(define (common:false-on-exception thunk #!key (message #f))
  (handle-exceptions exn
                     (begin
                       (if message
                           (debug:print-info 0 *default-log-port* message))
                       #f) (thunk) ))

(define (common:file-exists? path-string #!key (silent #f))
  ;;;; TODO: catch permission denied exceptions and emit appropriate warnings. Might be able to get rid of with chicken 5?
  (common:false-on-exception (lambda () (file-exists? path-string))
                             message: (if (not silent)
                                          (conc "Unable to access path: " path-string)
                                          #f)
                             ))

(define (common:directory-exists? path-string)
  ;;;; TODO: catch permission denied exceptions and emit appropriate warnings
  (common:false-on-exception (lambda () (directory-exists? path-string))
                             message: (conc "Unable to access path: " path-string)
                             ))

;;======================================================================
;; does the directory exist and do we have write access?
;;
;;    returns the directory or #f
;;
(define (common:directory-writable? path-string)
  (handle-exceptions
      exn
    (begin
      (debug:print 0 *default-log-port* "Failed to identify access to " path-string ", exn=" exn)
      #f)
   (if (and (directory-exists? path-string)
            (file-write-access? path-string))
       path-string
       #f)))

;;======================================================================
;; config file utils
;;======================================================================

(define (lookup cfgdat section var)
  (if (hash-table? cfgdat)