Determine calling scope in PHP

Is there a way to determine the scope in which a function is called from inside the function itself? (Or method; I'll use function to mean either in the remainder of开发者_如何学C the post.)

What I do not want is to have to pass __FILE__ or __CLASS__ constants into the function. This information is available in stack traces, etc. so I know it's floating around somewhere, but I'd like to know how to introspect it at runtime without throwing exceptions.

If there are any performance particularities for a solution, I'd like to know about those as well.

There are two use-cases I'm interested in.

1. Determine which file / line / function called my function
2. Determine the class type that originated the function call

Basically what I want is this:

class util
{
    public static function checkScope()
    {
        echo $magic_scope_stuff;
    }

    public static function blah()
    {
        util::checkScope();
    }
}

util::checkScope(); // main, line 14
util::blah(); // class util, line 9

There's debug_backtrace() for that.

The resulting array gives you a call trace from the entry point until the invocation of debug_backtrace.