Autosaving stacks corrupted on network drives

[Brian Milby]

The stack file isn’t a package.  If using an old format, then it may have a
resource fork.  The stack is read into memory and the file closed (not sure
how resource fork stuff is handled though).

On Wed, Oct 25, 2017 at 12:16 PM Mike Kerner via use-livecode <
use-livecode at lists.runrev.com> wrote:

> I was thinking about the mechanics of this.  A stack is really a
> folder/bundle, at least on macos/ios, so I wonder if parts of the stack
> bundle are open and parts are not, which could really make things
> problematic...
>
> On Wed, Oct 25, 2017 at 1:12 PM, Bob Sneidar via use-livecode <
> use-livecode at lists.runrev.com> wrote:
>
> > 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 at 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 <
> MikeKerner at 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 at 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 at 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).
> > >>>
> > >>>
> > >>> _______________________________________________
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> > >>
> > >>
> > >>
> > >> --
> > >> 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."
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>
>
>
> --
> 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 at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your
> subscription preferences:
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>