Megatest

  ;;
  ;; for the inmem approach (see dbmod.scm)
  ;; this is one db per server
  (inmem     #f)  ;; handle for the in memory copy
  (dbfile    #f)  ;; path to the db file on disk
  (dbfname   #f)  ;; short name of db file on disk (used to validate accessing correct db)
  (ondiskdb  #f)  ;; handle for the on-disk file
  (dbtmpname #f)  ;; path to db file in /tmp (non-imem method)
  (dbdat     #f)  ;; create a dbdat for the downstream calls such as db:with-db
  (last-update 0)
  (sync-proc #f)
  )

;; NOTE: Need one dbr:subdb per main.db, 1.db ...
;;

			  (string->number res)
			  #f)))
          (if newres
              newres
              res))
        res)))

;; timestring+identifier+payload
;; locks are unique on identifier, payload is informational
(define (db:extract-time-identifier instr)
  (let ((tokens (string-split instr "+")))
    (match tokens
      ((t i)(cons (string->number t) i))
      ((t)  (cons (string->number t) #f))
      (else
       (assert #f "FATAL: db:extract-time-identifier handed bad data "instr)))))

;; transaction protected lock aquisition
;; either:
;;    fails    returns  (#f . lock-creation-time)
;;    succeeds (returns (#t . lock-creation-time)
;;    fails    returns  (#f lock-creation-time identifier)
;;    succeeds (returns (#t lock-creation-time identifier)
;; use (db:no-sync-del! db keyname) to release the lock
;;
(define (db:no-sync-get-lock-with-id db keyname identifier)
  (sqlite3:with-transaction
   db
   (lambda ()
     (condition-case
      (let* ((curr-val (db:no-sync-get/default db keyname #f)))
	(if curr-val
	    (match (db:extract-time-identifier curr-val)
	    (match (db:extract-time-identifier curr-val) ;; result->timestamp, identifier
	       ((timestamp ident)
		(if (equal? ident identifier)
		    #t     ;; this *is* my lock
		    #f))   ;; nope, not my lock
	       (else #f))  ;; nope, not my lock
	    (let ((lock-value (if identifier
		    (cons #t timestamp)    ;; this *is* my lock
		    (cons #f timestamp)))  ;; nope, not my lock
	       (else (cons #f #f)))  ;; nope, not my lock
	    (let ((curr-sec (current-seconds))
		  (lock-value (if identifier
				  (conc (current-seconds)"+"identifier)
				  (current-seconds))))
	      (sqlite3:execute db "INSERT OR REPLACE INTO no_sync_metadat (var,val) VALUES(?,?);" keyname lock-value)
	      #t)))
	      (cons #t curr-sec))))
      (exn (io-error)  (dbfile:print-err "ERROR: i/o error with no-sync db. Check permissions, disk space etc. and try again."))
      (exn (corrupt)   (dbfile:print-err "ERROR: database no-sync db is corrupt. Repair it to proceed."))
      (exn (busy)      (dbfile:print-err "ERROR: database no-sync db is locked. Try copying to another location, remove original and copy back."))
      (exn (permission)(dbfile:print-err "ERROR: database no-sync db has some permissions problem."))
      (exn () ;; (status done) ;; I don't know how to detect status done but no data!
	   (dbfile:print-err "ERROR: Unknown error with database no-sync db message: exn="(condition->list exn)", \n"
			     ((condition-property-accessor 'exn 'message) exn))