Copy a file, renaming it if the destination already exists.

I would love some feedback on this little utility function:

/**
 * Copy $src to $dest, renaming it if the desired destination already exists.  The
 * string '.versionX' is inserted before the file extension if a file must be
 * renamed, with X incremented as needed.
 *
 * @return boolean true if copy was successful, false otherwise.
 */
public static function copy_with_rename($src, $dest)
{
    if (file_exists($dest))
    {
        // See if it's the same.
        $existingFileHash = sha1_file($dest);
        $new_file_hash = sha1_file($src);
        if ($existingFileHash != $new_file_hash)
        {
            // File of same name exists, but is different.
            $last_dot_pos = strrpos($dest,'.');
            $file_count = 2;
            // So find a new name.
            do
            {
                $base_name = substr($dest, 0, $last_dot_pos);
                $ext = substr($dest, strlen($base_name)); // with dot
                $new_name = $base_name.'.version'.$file_count.$ext;
                $file_count++;
            } while (file_exists($new_name) && sha1_file($src)!=sha1_file($new_name));
            // And then try the copy again, with the new name.
            return file::copy_with_rename($src, $new_name);
        } else
        {
            return true;
        }
    } else
    {
        $dest_dir = dirname($dest);
        // Create (to any depth) the destination directory, if required.
        if (!file_exists($dest_dir))
        {
            mkdir($dest_dir, 0777, true);
        }
        // And finally do the actual copy.
        return copy($src, $dest);
    }
}

Original Answer:

I'd put in some extra brackets in your while-loop for radability:

while ( file_exists($new_name) 
        && (sha1_file($src) != sha1_file($new_name))
      );

And you shouldn't set file-permissions to 777 by default (660 or even less). Everything else looks quite ok in my eyes (although I don't like the do/while construct, but I guess that's more a personal thing)

Update for comment:

$srcSH1 = sha1_file($sec);
do
{
    // ...
}
while ( file_exists($new_name) 
        && (sha1_file($new_name) != $srcSH1)
      );

You should move out the sha_file($src) as this doesn't change but is recalculated each iteration. And that's the case why I don't like do/while. Splits the $srcSH1 and the while-condition where it is used.

StackExchange Code Review Q#2647, answer score: 3