Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!wuarchive!decwrl!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Add a sound to 'opening a folder' ?
Message-ID: <9395@hoptoad.uucp>
Date: 24 Dec 89 09:00:12 GMT
References: <175@all41.csc.ti.com>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 53

In article <175@all41.csc.ti.com> smaass@all41.csc.ti.com writes:
>I am looking for a way to attach sounds to opening a folder.
>
>A friend suggested that I look at Soundmaster. Although there are many neat
>things that can be done with Soundmaster, I don't see that it will do what I am
>looking for.
>
>Is it possible to do this? Does anybody have solution?

Do you mean in the Finder or in Standard File?  A fairly
straightforward trap patch should do it in either case.

In the Finder, the opening of a folder causes a NewWindow call.  You
can check to see if your patch to the NewWindow trap (installed at INIT
time) runs under the Finder by comparing the strings at $2e0
(FinderName) and $910 (CurApName) are the same.  If not, jump to the
old address.  If they are the same, then you should check that the
defProc is 0; if not, jump to the old address.  If the defProc is
eight, you may assume that a folder was opened; play the sound.  Then
jump to the old address.  (This will still work even if Finder starts
calling GetNewWindow -- GNW goes through NewWindow.)

(It's possible someone else will do a NewWindow with type 8 under the
Finder; if so, you will play your sound, but the world will not end.
This would likely be a desk accessory; I've checked all the standard
DAs in 6.0 and they all use 0.  Variation code 8 indicates a zoom box,
which is unlikely to be used by a desk accessory.)

In Standard File, you have to be a little more subtle.  You can tell
when a new folder is opened by patching the generic Standard File
Package trap.  As described in IM v4, the fake item number 103 is
passed when a new folder is opened.  So your patch is a front-end to
Standard File, accepting SFGetFile, SFPGetFile, SFPutFile, and
SFPPutFile traps, saving their item filter procedures if any.  Then
call SFPGetFile or SFPPutFile, with your own item filter in place.
This can call the saved item filter procedure (if any; else default),
see if the item is still 103, and if so, play the sound.

It need not be a tail patch, since you don't need to keep control after
the trap -- you have already installed your filter, so you can just
replace the filter argument on the stack and jump to the old trap
address.  (However, this is one of those traps that it's pretty safe to
tail patch, since it almost always gets called only from user software,
not from the OS.)

Of course, both of them can only be done by a programmer.  I don't know
of any user-type solution, sorry.
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

"Satanic is merely the name they give to the behavior of those who would
 disrupt the orderly way in which men want to live."
    -- Gabrielle, THE VAMPIRE LESTAT, Anne Rice