NSDirectoryEnumerator ignores 1 file in the enumeration?

Question

I'm clearing my app's Documents folder using a NSDirectoryEnumerator. It works, mostly, except that for some reason that I cannot fathom, it leaves 1 file behind. Here's my code:

        NSDirectoryEnumerator * enumerator = [fileMan enumeratorAtURL:[NSURL fileURLWithPath:docsFolder()] includingPropertiesForKeys:nil options:NSDirectoryEnumerationSkipsSubdirectoryDescendants errorHandler:^BOOL(NSURL *url, NSError *error) {
        NSLog(@"%@,%@",url,error);
        return YES;
    }];
    for (NSURL * fileURL in enumerator) {
        BOOL removed = [fileMan removeItemAtURL:fileURL error:nil];
        NSLog(@"Removed %@:%d",fileURL.path,removed);
    }

The docsFolder() call in the above code is a function which simply returns the app's documents folder, using NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES). I've breakpointed and logged in the error handler, it never hits. I've got a ton of files in there, they all get deleted fine. Except, there's always one file, always the same file, that gets left behind. This is in iOS 8.1, in the Simulator. Even if, for some reason, the file was locked (or whatever else) the error handler should have gotten called, so I'm at a loss as to what is happening.

Could it have something to do with the fact that all the files in the Documents folder are "hard" links to files in a separate folder? What would cause a hard link to not get... unlinked?

Anyone have any ideas why this might be happening?

What's the name of the file that get's left? Is it always the same file? — rmaddy, Nov 04 '14 at 06:53
Always the same file: `b0da83f43a90ed65c6f4976969345df4.jpeg`. — Dhiraj Gupta, Nov 04 '14 at 06:54
Instead of passing nil in error parameter, pass a NSError object and check it's data — Midhun MP, Nov 04 '14 at 06:57
@MidhunMP Only check the error if `removeItemAtURL:error:` returns `NO`. — rmaddy, Nov 04 '14 at 06:58
@rmaddy: yes, you are correct. Didn't mentioned that in my comment :) — Midhun MP, Nov 04 '14 at 07:03
Edited post to include the fact that the files are all hard links to files in a different folder. — Dhiraj Gupta, Nov 04 '14 at 08:10
@rmaddy, @MidhunMP, I've added a breakpoint inside an `if` that checks if removed is NO but it never hits either. — Dhiraj Gupta, Nov 04 '14 at 08:13

score 0 · Answer 1 · answered Nov 19 '14 at 17:56

0

You are deleting files while enumerating them. This confuses the enumerator. A safer approach would be: enumerate the files and collect their names into an array. After the enumeration ends, go through the array and delete the files.

answered Nov 19 '14 at 17:56

Andrei Belogortseff

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I've tried this approach, but it doesn't cause any difference. I collected all the enumerated URLs in an NSMutableArray and then after finishing the directory enumerator, I deleted using the array. – Dhiraj Gupta Nov 20 '14 at 03:18

score 0 · Answer 2 · answered Nov 19 '14 at 18:09

If you just want to delete everything in a directory, but not the containing directory, try this:

NSArray *directoryContents = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:nil];
for (NSString *item in directoryContents) {
    [[NSFileManager defaultManager] removeItemAtPath:[path stringByAppendingPathComponent:item] error:nil];
}

Should probably check the errors too.

NSDirectoryEnumerator ignores 1 file in the enumeration?

2 Answers2