Re: Convert NSString to FSRef

FROM : Adam R. Maxwell
DATE : Sat Mar 15 20:23:18 2008

On Mar 15, 2008, at 12:04 PM, Kevin Dixon wrote:

> I'm trying to write a method that will convert a NSString containing a
> file system URL to an FSRef with the following code
>
> - (FSRef)stringToFSRef: (NSString*)filePath {
>     FSRef output;
>
>     CFStringRef cfFilePath = CFStringCreateWithCString(NULL, [filePath
> cString], (CFStringEncoding)8);


-cString has been deprecated for a very long time; it's better to use 
UTF8String.  In this case, however, you can cast (NSString *) to 
CFStringRef.  Check the docs on toll-free bridging.

>     CFURLRef url = CFCreateURLWithString(NULL, cfFilePath, NULL);
>
>     CFURLGetFSRef(url, &output);
>
>     return output;
> }
>
> I am getting a warning on the CFCreateURLWithString, saying
> "initialization makes pointer from integer without a cast"


There's no such function.  You probably meant CFURLCreate... instead. 
For an easier solution, try this:

NSURL *aURL = [NSURL fileURLWithPath:filePath];
CFURLGetFSRef((CFURLRef)aURL, &output);

which also fixes your CFString and CFURL leaks.

Another problem is that you have no way of returning an error in case 
CFURLGetFSRef fails, so you might want to either return the FSRef by 
reference and return a BOOL or pass in a BOOL * to return a failure 
value by reference.

hth,
Adam