从PHP中的文件内容获取完全限定的类名

<?phpfunction get_class_from_file($path_to_file){    //Grab the contents of the file    $contents = file_get_contents($path_to_file);    //Start with a blank namespace and class    $namespace = $class = "";    //Set helper values to know that we have found the namespace/class token and need to collect the string values after them    $getting_namespace = $getting_class = false;    //Go through each token and evaluate it as necessary    foreach (token_get_all($contents) as $token) {        //If this token is the namespace declaring, then flag that the next tokens will be the namespace name        if (is_array($token) && $token[0] == T_NAMESPACE) {            $getting_namespace = true;        }        //If this token is the class declaring, then flag that the next tokens will be the class name        if (is_array($token) && $token[0] == T_CLASS) {            $getting_class = true;        }        //While we're grabbing the namespace name...        if ($getting_namespace === true) {            //If the token is a string or the namespace separator...            if(is_array($token) && in_array($token[0], [T_STRING, T_NS_SEPARATOR])) {                //Append the token's value to the name of the namespace                $namespace .= $token[1];            }            else if ($token === ';') {                //If the token is the semicolon, then we're done with the namespace declaration                $getting_namespace = false;            }        }        //While we're grabbing the class name...        if ($getting_class === true) {            //If the token is a string, it's the name of the class            if(is_array($token) && $token[0] == T_STRING) {                //Store the token's value as the class name                $class = $token[1];                //Got what we need, stope here                break;            }        }    }    //Build the fully-qualified class name and return it    return $namespace ? $namespace . '\\' . $class : $class;}

摘自：http://jarretbyrne.com/2015/06/197/