Documentation for USBHost_t36?

[JKIM]

I am trying to understand the general architecture of the HID device drivers in the USBHost_t36 library.
I didn't find any overview docs on the library, so I am researching it from the code.

Specifically, I don't understand how the relationship between different objects is established, like the host object, a hub, hid parser and the hid device.

As an example (and this may be my lack of skill with C++):

Creating a MouseController object includes the following initialization:

USBHost myusb;
USBHub hub1(myusb);
USBHIDParser hid1(myusb);
MouseController mouse1(myusb);

But looking at the constructor for the MouseController, it doesn't seem to do *anything* with the USBHost that is passed in:

MouseController(USBHost &host) { init(); }

I see this same pattern with USBHub as well, so I must be missing something!

as well, I don't understand the call to check if a driver has been claimed, such as:

if(mouse1)
{
}

I expect that be a pointer to the mouse1 object that was previously instantiated, but the check does return false if the driver hasn't been claimed.

Any clues on what I should look at to understand this?

 

[JKIM]

OK, I think the USBHIDInput override for operator bool() is responsible for the driver claiming boolean:

class USBHIDInput {
public:
    operator bool() { return (mydevice != nullptr); }

https://github.com/PaulStoffregen/USBHost_t36/blob/master/USBHost_t36.h#L523

 

[JKIM]

OK, I am guessing the constructor doesn't use the USBHost parameter, but the constructor is defined this way to force the caller to have already created a USBHost object as a safeguard?