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Re: Algorithm for "preferred application" changed in Tiger?
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Re: Algorithm for "preferred application" changed in Tiger?



On May 31, 2005, at 12:44 PM, Dan Smith wrote:

I've noticed that in Tiger, quite a few of my files have changed their Finder

icons, and the default application with which they open. 


For example, almost all of my MPW files now display in the Finder as "Kind: C

Source File" and "Kind: C Header Source File" and launch ProjectBuilder when

double-clicked. (Mac OS 9) Nisus Writer files display as generic text files

and, when double-clicked, open in TextEdit. 


I can't completely characterize all of this behavior, but some text files

display as generic documents. It is possible to open them by dragging them to a

text editor, but very difficult to convince the Finder that they should always

be opened with a text editor. 


Finally, it appears that Spotlight does not consider "C Source Files" and "C

Header Source Files" to be text file... even though they have HFS+ TYPE=TEXT...

and therefore they do not show up in Spotlight searches. At least not by

default.


Without trying to be too tendentious about it, it appears as if some change in

LaunchServices or something has been made which puts less weight on, or

ignores, the HFS+ TYPE and CREATOR.


Oddly enough, .c and .h files created with CodeWarrior seem to have retained

their associations... and .rsrc files still open with ResEdit and continue to

do so if their extensions are changed. So extensions do not always trump

TYPE/CREATOR.


1) Can someone point me to the documentation that explains exactly what was

changed in 10.4 and what algorithms are now in effect?


2) Does anyone know what happens if I select an MPW file with extension .c,

TYPE=TEXT, CREATOR=MPS, and tell the Finder to use MPW to open all files "like"

this? I would hope that only files with TYPE=TEXT and CREATOR=MPS would be

considered "like this," but I am afraid to do it for fear it will change the

association of EVERY .c file.



This is due to the introduction of Spotlight and the spread of Uniform Type Identifiers (UTIs) through Apple application Info.plist files.  UTIs are a more precise mechanism for denoting the content type of files, but in some ways they overlap the functionality of type/creator attributes and extensions.  LaunchServices, which determines what icon a file has and what application is used to open it by default, now puts a file's UTI bindings at a higher precedence than its file extension binding or its type/creator binding.  Because some applications don't assign UTIs yet, apps that do assign a UTI are now "claiming" files that used to be owned by apps that do not assign UTIs.

More on UTIs is explained at
http://developer.apple.com/documentation/Carbon/Conceptual/understanding_utis/index.html

The LaunchServices team knows about this problem and is looking at ways to address it.

Chris
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 >Algorithm for "preferred application" changed in Tiger? (From: "Dan Smith" <email@hidden>)



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