Question

I am running Apache HTTP server 2.4 on a Windows Server 2008 R2 machine with PHP 5.4.4.

I have the following directory structure on my E:\ drive:

E:\Dir1\Dir2\Dir3

All of the directories (Dir1, Dir2 and Dir3) are empty (they have no files) except for the child directories shown above.

I am trying to delete Dir3 and then look at the contents of directory Dir2 to make sure that there’s nothing there. I have written the following PHP script to test this:

<?php

    $currentDir = "E:\\Dir1\\Dir2\\Dir3";

    $parentDir = dirname( $currentDir );  // Get the parent directory for Dir3.
        
    rmdir ( $currentDir );  // Remove directory Dir3.
    
    echo "<b>Current directory:</b> " . $currentDir . " <b><< I don't exist, I was just deleted.</b><br />";
    echo "<b>Parent directory:</b> " . $parentDir. "<br />";
                
    echo "<b>According to 'scandir', the parent directory contains:</b> ";
    print_r( scandir( $parentDir, SCANDIR_SORT_NONE ) );
    echo "<br /><br />";

?>

If I do not have Dir3 open in Windows Explorer, the script above woks perfectly and delivers the following output:

Current directory: E:\Dir1\Dir2\Dir3 << I don’t exist, I was just deleted.

Parent directory: E:\Dir1\Dir2

According to ‘scandir’, the parent directory contains: Array ( [0] => . [1] => .. )

However, if I have Dir3 open in Windows Explorer, I get the following output:

Current directory: E:\Dir1\Dir2\Dir3 << I don’t exist, I was just deleted.

Parent directory: E:\Dir1\Dir2

According to ‘scandir’, the parent directory contents: Array ( [0] => . [1] => .. [2] => Dir3 )

Notice that Dir3 appears in the array of contents for Dir2. In other words, scandir() thinks that Dir3 still exists even when I know for a fact that it doesn’t (Windows explorer kicks me back to Dir2).

Does anyone know why this is happening?

Answer 1

When you have the directory opened in windows explorer. There is an existing handle to the directory in the OS-es memory. Scandir internally fetches details of directory/file existence from the OS. So when the directory is open and you delete it and run a scandir immediately, then windows returns it because there is a "lock" on the directory handle. This handle closes only when you close the directory (or some internal garbage collections happens at the OS level I guess). When the directory is not open in windows explorer none of these edge cases are happening and so everything works like a charm.

Again one of the behaviors of windows. I think clearstatcache() is an option, but I believe it works only on posix-compliant Os-es and also scandir() is not affected by it.