Extract a fully qualfied (namespaced) classname from a php file. This function assumes PSR-0 compliance.

extractFullClassNameFromFile.function.php

/**
 * Extract a fully qualfied (namespaced) classname from a php file.
 * This function assumes PSR-0 compliance.
 *
 * @param   string  $filePath   Path to the php file.
 * @return  string|false        The resulting classname
 */
function extractFullClassNameFromFile($filePath)
{
    if (!file_exists($filePath)) {
        return false;
    }

    $namespace  = null;
    $classname  = null;
    $cnMatches  = null;
    $nsMatches  = null;
    $file       = file_get_contents($filePath);

    if (preg_match_all('/\n\s*(abstract\s|final\s)*class\s+(?<name>[^\s;]+)\s*/i', $file, $cnMatches, PREG_PATTERN_ORDER)) {
        $classname  = array_pop($cnMatches['name']);

        if (preg_match_all('/namespace\s+(?<name>[^\s;]+)\s*;/i', $file, $nsMatches, PREG_PATTERN_ORDER)) {
            $namespace  = array_pop($nsMatches['name']);
        }
    }

    if (empty($classname)) {
        return false;
    }

    return "$namespace\\$classname";
}