Re: Exclusive File Access

FROM : Ondra Cada
DATE : Thu Nov 21 14:54:57 2002

On Thursday, Nov 21, 2002, at 00:31 Europe/Prague, Rosyna wrote:

> I'm talking about exclusive write access only.

With general document-editing applications, we are lucky there is
nothing as that: again, it would be *QUITE* crippling.

I don't say there are no special apps which need it, but plain things
like TextEdit definitely do not.

> If another user opens a file already opened for write access, open it
> read-only.

Luckily, with standard document-based applications files are *NEVER*
opened read-write.

(i) when *document* is opened, *file* is opened read-only, read into
memory, and closed;
(ii) when document is saved,
   (a) another file is *created* beside the original one, with the new
contents;
   (b) the original file is removed (or renamed to *~.*)
   (c) the new file is renamed to the original name.

This is the *one* right way to do things for general document-based
applications. Again, if you have special needs, you have a number of
ways to fill them, but DON'T mess things up just for kicks.
---
Ondra Cada
OCSoftware:    <email_removed>              http://www.ocs.cz
private        <email_removed>            http://www.ocs.cz/oc
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