True, The stack is not open after it's read into memory. I can see why/why not this is done from a LC point of view. If the stack is being read in from a web server it's not possible to lock it. If the file is local/network then the stack could remain open and locked for write. Other processes could then open/read it but not save it. This looks like it's been around for a long time. Could locking stack(s) break existing projects? I vote to lock for write any open stacks.
Ralph DiMola IT Director Evergreen Information Services rdim...@evergreeninfo.net -----Original Message----- From: use-livecode [mailto:use-livecode-boun...@lists.runrev.com] On Behalf Of Bob Sneidar via use-livecode Sent: Wednesday, October 25, 2017 1:13 PM To: How to use LiveCode Cc: Bob Sneidar Subject: Re: Autosaving stacks corrupted on network drives Okay I think I see what is going on here. A Livecode stack, though it appears to be open in the IDE, is NOT open from the OS point of view. To test this, create a new livecode stack, save it, then attempt to delete it in the OS while it's still open in the IDE. If my theory is correct, you should have no problem doing so. I did this and sure enough, I was able to put the file in the trash, AND THEN EMPTY IT! But when I saved again in the IDE, it recreated the file. Bob S > On Oct 25, 2017, at 09:26 , Mike Kerner via use-livecode <use-livecode@lists.runrev.com> wrote: > > Now if what you're suggesting is that the server OS should manage the > access process so that you cannot have two simultaneous accesses, I > would agree, but my experience has been that it doesn't always work that way. > > On Wed, Oct 25, 2017 at 12:19 PM, Mike Kerner > <mikeker...@roadrunner.com> > wrote: > >> I'm saying that it is possible to access the same file from the same >> share from multiple machines and leave the file in an indeterminate >> or corrupted state, afterwards, especially if both machines accessing >> the share are trying to save changes to said file. The purpose of >> the semaphore would be to stop the simultaneous access of the file from multiple machines. >> >> >> On Wed, Oct 25, 2017 at 11:54 AM, Bob Sneidar via use-livecode < >> use-livecode@lists.runrev.com> wrote: >> >>> I thought the OS takes care of that. Are we saying that when saving >>> to a network share this process of creating the semaphore file does not happen? >>> >>> Bob S >>> >>> >>>> On Oct 24, 2017, at 16:01 , Mike Kerner via use-livecode < >>> use-livecode@lists.runrev.com> wrote: >>>> >>>> Possible solutions: >>>> 1) Do what LibreOffice does. Create an invisible semaphore file >>>> that >>> the >>>> stack checks for on open. If it exists, the open is rejected and >>>> the >>> stack >>>> immediately closes. This will keep secondary and simultaneous >>>> users >>> from >>>> getting their grubby paws into the stack before the save/sync is >>> complete. >>>> As part of this solution, I would suggest any quit/closeStack event >>>> has >>> a >>>> built in delay to confirm that the sync/save has completed before >>> removing >>>> the semaphore. This is still tricky as you are at the mercy of the >>>> sync/save tool, however, if you're clever, you can use the >>>> service's >>> api to >>>> check, separately, if the sync/save is complete before you let LC >>>> finish closing down. >>>> 2) Split the data out into a separate data file or better into a >>> database >>>> (because most databases use transactions, with greatly minimizes >>>> the probability of corruption). >>> >>> >>> _______________________________________________ >>> use-livecode mailing list >>> use-livecode@lists.runrev.com >>> Please visit this url to subscribe, unsubscribe and manage your >>> subscription preferences: >>> http://lists.runrev.com/mailman/listinfo/use-livecode >>> >> >> >> >> -- >> On the first day, God created the heavens and the Earth On the second >> day, God created the oceans. >> On the third day, God put the animals on hold for a few hours, >> and did a little diving. >> And God said, "This is good." >> > > > > -- > On the first day, God created the heavens and the Earth On the second > day, God created the oceans. > On the third day, God put the animals on hold for a few hours, > and did a little diving. > And God said, "This is good." > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
