OSX10.9 tag manipulation util

metatag.m

#import <Foundation/Foundation.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

// clang tag.m -o metatag -framework "foundation" -fobjc-arc && ./metatag

int main(int argc, char **argv) {
    char *tagToAdd = NULL;
    char *tagToRemove = NULL;

    int c;
    while ((c = getopt (argc, argv, "a:r:")) != -1) {
        switch (c)
        {
            case 'a':
                tagToAdd = optarg;
                break;
            case 'r':
                tagToRemove = optarg;
                break;
            case '?':
                fprintf (stderr,
                        "Unknown option character `\\x%x'.\n",
                        optopt);
                return 1;
            default:
                abort();
        }
    }

    NSError *error;

    NSMutableArray *files = [NSMutableArray array];
    for (int index = optind; index < argc; index++) {
        NSString *path = [NSString stringWithCString:argv[index] encoding:NSUTF8StringEncoding];
        NSURL *url = [[NSURL fileURLWithPath:path] absoluteURL];

        if (tagToAdd) {
            NSString *tag = [NSString stringWithCString:tagToAdd encoding:NSUTF8StringEncoding];

            id tags;
            [url getResourceValue:&tags forKey:NSURLTagNamesKey error:&error];
            if (tags) {
                tags = [tags mutableCopy];
                [tags addObject:tag];
            } else {
                tags = @[tag];
            }

            [url setResourceValue:tags forKey:NSURLTagNamesKey error:&error];
        }

        if (tagToRemove) {
            NSString *tag = [NSString stringWithCString:tagToRemove encoding:NSUTF8StringEncoding];

            id tags;
            [url getResourceValue:&tags forKey:NSURLTagNamesKey error:&error];
            if (tags) {
                tags = [tags mutableCopy];

                tags = [tags objectsAtIndexes:[tags indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
                    return ([tag isEqualToString:obj] == NO);
                }]];
                [url setResourceValue:tags forKey:NSURLTagNamesKey error:&error];
            }
        }
    }

    return 0;
}