On 16 Jun 2009, at 23:49, Stefan Bidigaray wrote:
I'll try to be to the point... I'm need to be able to find some
bundles that conform to a particular protocol so that I can load
them and maybe use them. I've been reading the Apple docs and I
already know how to search the bundle directories and use -
conformWithProtocol:. What I'm having a hard time grasping is, how
do I find out if the bundle I'm looking at actually meets my
criterias before loading it? Is this even possible? Since NSBundle
doesn't support unloading (at least according to Apple) I don't want
to load every single bundle in the system just to then find out they
are just going to take up space. I've read the Apple Plug-in docs
and NSBundle Programming Guide, but I still don't know how to do
what I'm trying to.
I'm not at all sure you can.
It's true to say that you can't unload bundle code ... the gnu runtime
doesn't support it, and while I think I read somewhere that Apple's
new 64bit runtime would support it, the standard one definitely didn't
last time I looked.
As far as I'm aware, there's no convention for storing the protocols
supported by a bundle's principal class in its info.plist, so I don't
see how you can check what a bundle does without loading the code.
I think the normal way that an application determines which bundles to
load is by using its own directory/filename conventions, so you just
search the bundle directories for bundles with the correct names or
bundles in subdirectories with the correct names.
> FYI: this is for the NSSound reimplementation effort... I'm trying
to support multiple "plug-ins".
Well, as NSSound is a gui class, presumably bundles for it should
count as gui library resources. In GNUstep we do have a standard
location for gui library resources, and the GNUstep extension [NSBundle
+bundleForLibrary:version:] returns the bundle for that location. The
problem is, that only returns the bundle in the first domain found
(assumed to be the one associated with the library being used), and I
guess with plugins you would want to allow bundles to be provided by
something other than the standard gui library.
So, I think you are going to have to define your own conventions for
this.
I would suggest using
NSSerarchPathForDirectoriesInDomains(NSLibraryDirectory,
NSAllDomainsMask,YES) to get a list of library directories, then look
for specific naming patterns in those library directories.
eg.
Assuming your bundles are those with an 'nssound' extension located in
the 'Bundles' subdirectory ...
{
NSString *path;
NSArray *paths;
NSBundle *bundle;
NSEnumerator *enumerator;
NSMutableArray *all;
/* Gather up the paths */
paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,
NSAllDomainsMask, YES);
enumerator = [paths objectEnumerator];
all = [NSMutable array arrayWithCapacity: 10];
while ((path = [enumerator nextObject]) != nil)
{
bundle = [self bundleWithPath: path];
paths = [bundle pathsForResourcesOfType: @"nssound"
inDirectory: @"Bundles"];
[all addObjectsFromArray: paths];
}
return all;
}
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