A basic sketch of an NSFileReference class interface

NSFileReference.h

@interface NSFileReference : NSObject {
    // internal storage would probably be NSURL, but could be
    // NSString holding a path, FSRef, alias data, whatever
}

- (id)initWithPath: (NSString *)path;
- (id)initWithFileSystemRepresentation: (const char *)path;
- (id)initWithFSRef: (FSRef *)ref;
- (id)initWithAliasData: (NSData *)data;
- (id)initWithURL: (NSURL *)url;

- (NSString *)path;
- (const char *)fileSystemRepresentation;
- (BOOL)getFSRef: (FSRef *)outRef;
- (NSData *)aliasData;
- (NSURL *)url;

// in a perfect world, these two would return two different classes too
- (NSString *)name;
- (NSString *)displayName;

- (NSArray *)displayComponents;

- (NSFileReference *)parent;
- (NSFileReference *)childNamed: (NSString *)name;

@end