Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!ames!elroy!usc!hacgate!ashtate!dbase!awd
From: awd@dbase.UUCP (Alastair Dallas)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Mac file IO
Summary: File name is enough
Message-ID: <93@dbase.UUCP>
Date: 9 Jun 89 00:59:11 GMT
References: <16464@paris.ics.uci.edu> <3264@cps3xx.UUCP>
Organization: Ashton Tate Devlopment Center Glendale, Calif.
Lines: 39

In article <3264@cps3xx.UUCP>, rang@cpsin3.cps.msu.edu (Anton Rang) writes:
> In article <16464@paris.ics.uci.edu> poleary@BONNIE.ICS.UCI.EDU (Peter O'Leary) writes:
> 
>    An application that I am working on needs to save information on a file so
>    that that file may be opened later.  What is the minimum amount of info []
>    that is needed in order to get at a file?  So far, I have been storing the
>    file's name and volume reference number.
> 
> It depends on how much later you need the file, to some extent, but
> what I'd recommend storing is:
> 
> 	Volume name (refnum is only valid for one session)
> 	Directory ID (for an HFS volume)
> 	File name
> 


Like another current thread in comp.sys.mac.programmer, I think the answer
here is: "There is already a Macintosh way of doing this."  The minimum amount
of information to store is whatever the user enters to name the file in the
first place.  If she renames the file or shuffles directories between the
time she writes the file and the time she reads the file, the program should
just politely pull up SFGetFile and say "where the H*ll is <filename>?".
Of course, if she navigates in SFPutFile, you might want the Volume and
Directory, but you want to ignore those things if the user ignored them
(used the default working directory) when she saved the file.  The way to
detect navigation in SFPutFile is to compare the working directory before
and after the SFPutFile call (that's off the top of my head, I'll be corrected
if I'm wrong, I'm sure).

User brings up your program, writes out a file by doing nothing more than
typing Foo in the SFPutFile dialog.  Back at Finder, realizes that Foo is
now in same folder as the program.  Moves Foo to a floppy.  Months later,
inserts floppy, dbl-clicks Foo--your program tells him forget it because
Volume and Directory don't match?  Wouldn't be friendly...

(Long-winded today, aren't I?)

/alastair/