iphone - Make a tree class with cftree - iphone

Question

I want to make a tree class like NSArray with CFTree.
(Actually NSTree doesn't exist so I'm trying to make 'NSTree like tree'.)
But CFTree seems to request certain type class.
I want to make a general class that can deal in various class like NSArray.
Here is iPhone dev site's example.
static CFTreeRef CreateMyTree(CFAllocatorRef allocator) {
MyTreeInfo *info;
CFTreeContext ctx;
info = CFAllocatorAllocate(allocator, sizeof(MyTreeInfo), 0);
info->address = 0;
info->symbol = NULL;
info->countCurrent = 0;
info->countTotal = 0;
ctx.version = 0;
ctx.info = info;
ctx.retain = AllocTreeInfo;
ctx.release = FreeTreeInfo;
ctx.copyDescription = NULL;
return CFTreeCreate(allocator, &ctx);
}
I want to use general class instead of "MyTreeInfo".
Is there any way?
Thanks.

Answer 1

Sure, CFTree can hold any data you want. If you want to store instances of CFType, then just set the retain and release of the context to CFRetain and CFRelease. You can also then set copyDescription to CFCopyDescription. Something like this:
static CFTreeRef CreateMyTree(CFTypeRef rootObject) {
CFTreeContext ctx;
ctx.version = 0;
ctx.info = rootObject;
ctx.retain = CFRetain;
ctx.release = CFRelease;
ctx.copyDescription = CFCopyDescription;
return CFTreeCreate(NULL, &ctx);
}
...
CFStringRef string = CFSTR("foo");
CFTreeRef tree = CreateMyTree(string);
NSLog(#"%#", tree);
CFRelease(tree);