Recursive delete of directory - Directory not empty error

Posted by Gordon on April 14, 2008, 12:14 pm

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I'm trying to remove a directory and all its contents from within a
script. I wrote a recursive function to take care of it, but when I
run it I get random "Directory not empty" error messages.

I dropped some code in to echo out the name of the file that's about
to be rmdir()ed or unoink()ed (depending if it's a file or a
directory) to see if it was choking on a particular subdirectory, but
doing that causes all the error messages to stop appearing!

It looks to me as if at some stages of the script the delete commands
are being issued too rapidly and the result is that an attempt to
delete a parent is made before its children have all been deleted.
The code I added to echo out the directory name first probably
introduces just enough of a delay for this problem to go away.

Obviously just doing something in the function to cause a delay isn't
a good solution, is there a better way of handling this problem?

I'm running PHP 5 on a Windows development machine through Apache.
Directory listings are being retrieved from a database.

Posted by =?ISO-8859-1?Q?=22=C1lvaro_G=2 on April 15, 2008, 8:32 am

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Gordon escribió:
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In the manual page for unlink() there's a user comment with sample code
for recursive deletion. I haven't tried it but who knows:

http://php.net/unlink

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-- http://alvaro.es - Álvaro G. Vicario - Burgos, Spain
-- Mi sitio sobre programación web: http://bits.demogracia.com
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Posted by The Natural Philosopher on April 15, 2008, 9:28 am

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Álvaro G. Vicario wrote:
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Normally thats because there are hidden or wrong permission files in it.

I suspect you need more subtle code, and if in Linux etc, some form of
attention to permissions if these are the problem.

Posted by Gordon on April 15, 2008, 10:02 am

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I don't think permissions are the problem, because the development
machine is Windows, and the error message being given is Directory Not
Empty. No Permission Denied errors are popping up in the output. I
also mentioned that the problem went away when I introduced a line of
code for debugging purposes into CmsItem::deleteItem(), which echos
the path being deleted to the output. My suspicion is that the calls
to rmdir are happening more rapidly than the filesystem can cope with
them. The debug code introduced just enough of a delay for the code
to work properly but without it attempts to delete a parent directory
can occur before the deletion of its children has completed, causing
the not empty error.

Posted by The Natural Philosopher on April 15, 2008, 10:27 am

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Gordon wrote:
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Ah. Caching.

I've had a similar problem with PHP creating a file that didn't actually
exist on disk till PHP exited.

So your are suggesting that PHP doesn't actually delete the files until
after the call to unlink the directory is received?

I would NOT be surprised. PHP'S file handling seems to be a bit flaky in
this area.

Windows should be capable of processing the calls as fast as they can be
sent: IT *should* simply block if the directory is still busy.

My guess - and its only a guess - is that PHP itself is caching the file
deletes. But not the directory deletes.

Or spitting them out in random order.

Maybe its possible to force a buffer flush in PHP.