Use $this in callback refer to callback class - php

Question

So, I have something like this:
class ClassA{
public function doCallback($callback){
call_user_func_array($callback, array());
}
public function doSomething(){
return 12345;
}
}
class ClassB{
public function runMe(){
$classA = new ClassA();
$classA->doCallback(function(){
$this->doSomething();
});
}
}
I am trying to figure out how, if possible I can use $this or something similar in a callback function that will refer to the class that the callback is running on (Not the class it is in) if that makes sense.
So in my above example I would like $this->doSomething(); where $this means ClassA and not ClassB. Currently $this is referring to ClassB. Is there something that I can use to say I want ClassA?
EDIT
Here is the actual method that I am using
public function save(){
$id = (int)$this->input->post("id");
$title = $this->input->post("title");
$uid = (int)$this->session->get("id");
$this->db->getTable("content")
->has(array("user_id" => $uid, "name" => $title), function(){
echo json_encode(array("error" => "Name already exists."));
}, function() use($id, $uid, $title){
//$this->db->getTable("content")
$this->update(array("name" => $title), array(
"user_id" => $uid,
"content_id" => $id), function($rows){
if($rows > 0){
$error = "";
}else{
$error = "Unknown error occurred";
}
echo json_encode(array("error" => $error));
});
});
}
$this->db->getTable("content") returns a Database Object, and has() is a method in the object. I was hoping that I could use a shorthand way to access $this->db->getTable("content") without having to call it again in the callback, or passing it through call_user_func_array as a parameter or without the use of use().
the method has():
https://github.com/ZingPHP/Zing/blob/master/Zing/src/Modules/Database/DBOTable.php#L311
EDIT
I think in my callback function I need to do something like this, but I don't think it is working:
public function myFunc(callback $callback){
$callback->bindTo($this, $this);
return call_user_func_array($callback, array());
}

Answer 1

You can go through the public interface of ClassA.
class ClassA
{
public function doCallback($callback)
{
call_user_func_array($callback, array());
}
public function doSomething()
{
echo "Doing something...\n";
}
}
class ClassB
{
private $_oSubject;
public function __construct(ClassA $oSubject)
{
$this->_oSubject = $oSubject;
}
public function runMe()
{
$this->_oSubject->doCallback(function() {
$this->_oSubject->doSomething();
});
}
}
$oA = new ClassA();
$oB = new ClassB($oA);
$oB->runMe();

Answer 2

I got it! I just need to add $newCallback = $callback->bindTo($this, $this); in the callback class, and then in ClassB I can use $this to refer to ClassA.
class ClassA{
public function doCallback($callback){
$callback = $callback->bindTo($this, $this);
call_user_func_array($callback, array());
}
public function doSomething(){
return 12345;
}
}
class ClassB{
public function runMe(){
$classA = new ClassA();
$classA->doCallback(function(){
$this->doSomething();
});
}
}