(macOS) Fetch local removable mounted volumes

probeRemovableMountedVolumes.m

/**
 * Probe local removable mounted volumes
 * @return      An array with NSURL objects
 */
+ (NSArray<NSURL *> *)probeRemovableMountedVolumes {
    NSArray *keys = [NSArray arrayWithObjects:NSURLVolumeIsEjectableKey,
                    NSURLVolumeIsLocalKey, NSURLVolumeIsReadOnlyKey,
                    NSURLVolumeIsRemovableKey, nil];
    NSArray *flags = [NSArray arrayWithObjects:@YES, @YES, @NO, @YES, nil];

    NSAssert(keys.count == flags.count,
            @"Inconsistent array size  %lu vs %lu", keys.count, flags.count);

    NSArray *urls = [[NSFileManager defaultManager]
        mountedVolumeURLsIncludingResourceValuesForKeys:keys
        options:NSVolumeEnumerationSkipHiddenVolumes];

    NSMutableArray<NSURL *> *volumes = [[NSMutableArray alloc] init];

    NSNumber *chk;
    NSURLResourceKey key;
    NSUInteger i;
    for (NSURL *url in urls) {
        for (i = 0; i < keys.count; i++) {
            key = [keys objectAtIndex:i];
            if (![url getResourceValue:&chk forKey:key error:nil])
                break;
            if ([chk boolValue] != [[flags objectAtIndex:i] boolValue])
                break;
        }
        if (i == keys.count) [volumes addObject:url];
    }

    return volumes;
}