Is It A Disk Image?

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A comment on an old StackOverflow answer of mine took me to task for a “partial answer” so I decided to improve it. Both posters wanted to know if a mounted device is a disk image. I wrote a simple routine using the DiskArbitration framework to test this given a file URL.

The code:

#import <DiskArbitration/DiskArbitration.h>
// …
– (BOOL)isDMGVolumeAtURL:(NSURL *)url
{
BOOL isDMG = NO;
if (url.isFileURL) {
DASessionRef session = DASessionCreate(kCFAllocatorDefault);
if (session != nil) {
DADiskRef disk = DADiskCreateFromVolumePath(kCFAllocatorDefault, session, (__bridge CFURLRef)url);
if (disk != nil) {
NSDictionary * desc = CFBridgingRelease(DADiskCopyDescription(disk));
NSString * model = desc[(NSString *)kDADiskDescriptionDeviceModelKey];
isDMG = ([model isEqualToString:@"Disk Image"]);
CFRelease(disk);
}
CFRelease(session);
}
}
return isDMG;
}
view raw SomeObject.m hosted with ❤ by GitHub

Usage:

BOOL isDMG = [someObject isDMGVolumeAtURL:[NSURL fileURLWithPath:@"/Volumes/Some Volume"]];

In the above “someObject” refers to whatever object you put this method in, of course. It should probably be a category on NSURL (so you could ask the url directly: BOOL isDMG = [volumeMountPointURL isDMG];). I hope you find it useful!