iPhone: NSFilemanager fileExistsAtPath:isDirectory: not working properly?

Question

I'm working on an app for jailbroken iPhones. I'm trying to get only the directories of an folder. so I'm doing this:

NSArray *contentOfFolder = [[NSFileManager defaultManager] directoryContentsAtPath:path];
NSLog(@"contentOfFolder: %@", contentOfFolder);
directoriesOfFolder = [[NSMutableArray alloc] initWithCapacity:100];
for (NSString *aPath in contentOfFolder) {
    NSLog(@"apath: %@", aPath);

    BOOL isDir;
if ([[NSFileManager defaultManager] fileExistsAtPath:aPath isDirectory:&isDir] &&isDir)
    {
        [directoriesOfFolder addObject:aPath];
        NSLog(@"directoriesOfFolder %@", directoriesOfFolder);
    }
}
NSLog(@"dirctories %@", directoriesOfFolder);

but look at what I get. when I get the content of the folder everything looks fine:

2009-07-28 23:23:35.930 Drowser[573:207] new path /private/var 2009-07-28 23:23:35.945 Drowser[573:207] contentOfFolder: ( Keychains, "Managed Preferences", MobileDevice, backups, cache, db, ea, empty, folders, lib, local, lock, log, logs, mobile, msgs, preferences, root, run, spool, stash, tmp, vm )

but then:

2009-07-28 23:23:35.950 Drowser[573:207] apath: Keychains 2009-07-28 23:23:35.954 Drowser[573:207] apath: Managed Preferences 2009-07-28 23:23:35.959 Drowser[573:207] apath: MobileDevice 2009-07-28 23:23:35.984 Drowser[573:207] apath: backups 2009-07-28 23:23:35.993 Drowser[573:207] apath: cache 2009-07-28 23:23:36.002 Drowser[573:207] apath: db 2009-07-28 23:23:36.011 Drowser[573:207] apath: ea 2009-07-28 23:23:36.019 Drowser[573:207] apath: empty 2009-07-28 23:23:36.028 Drowser[573:207] apath: folders 2009-07-28 23:23:36.037 Drowser[573:207] apath: lib 2009-07-28 23:23:36.046 Drowser[573:207] directoriesOfFolder ( lib )

only "lib"! is recognized as folder. how can that be? the others are folders too. I confirmed it via SSH.

does anyone have an idea? Am I doing something wrong?

Solution

This is a really easy mistake to make, but it's also really easy to fix. Enumerating the contents of a directory only gives you the name of the item, not the item's full path. You have to build the full path yourself. So where you have:

for (NSString *aPath in contentOfFolder) {
  NSLog(@"apath: %@", aPath);

  BOOL isDir;
  if ([[NSFileManager defaultManager] fileExistsAtPath:aPath isDirectory:&isDir] &&isDir) {
    [directoriesOfFolder addObject:aPath];
    NSLog(@"directoriesOfFolder %@", directoriesOfFolder);
  }
}

You should actually have this:

for (NSString *aPath in contentOfFolder) {
  NSString * fullPath = [path stringByAppendingPathComponent:aPath];

  BOOL isDir;
  if ([[NSFileManager defaultManager] fileExistsAtPath:fullPath isDirectory:&isDir] &&isDir) {
    [directoriesOfFolder addObject: fullPath];
  }
}

Comments

[Dan Rosenstark]

I'm sure I'm just exposing my ignorance on pointer syntax here, but don't you want a space between && and isDir?

[Dave DeLong]

@Yar: I usually put one in, but I fat fingered this one and left it out. However, I don't believe that it's syntactically required.

[Dan Rosenstark]

Understood, just checking that I'm not missing something. Thank you.