Duplicate filtering functions don't agreee

[pelikhan]

We have a device that requires this code path to match.

webusb/src/usb.ts

Line 173 in 0a3f331

if (filter.classCode) {

But the device pre-filter does not have this code path.

webusb/src/adapter.ts

Line 256 in 0a3f331

if (filter.classCode && filter.classCode !== device.deviceDescriptor.bDeviceClass) return false;

Should both filter be merged?

[thegecko]

Hmm, the usb.ts case follows the WebUSB specification correctly AFAICT.

The filter in the adapter is different and was used to find allowedDevices already selected. This bit is quite difficult as recognising a device as the same between plugs is hard (the unique address on the bus can change and other IDs such as SerialNumber and vid/pid are either optional or not unique).

My approach was to use a filter, but it's far from ideal, perhaps it should be swapped to storing a hash of known data.

This aside, I can see the same filter is being used here:

webusb/src/usb.ts

Line 291 in 0a3f331

return adapter.listUSBDevices(options.filters)

And it probably shouldn't, hence the issue you are seeing!

[thegecko]

@pelikhan Does deleting these lines fix your issue?

webusb/src/adapter.ts

Lines 255 to 262 in 0a3f331

	// Class
	if (filter.classCode && filter.classCode !== device.deviceDescriptor.bDeviceClass) return false;
	// Subclass
	if (filter.subclassCode && filter.subclassCode !== device.deviceDescriptor.bDeviceSubClass) return false;
	// Protocol
	if (filter.protocolCode && filter.protocolCode !== device.deviceDescriptor.bDeviceProtocol) return false;

[pelikhan]

it goes through but then i get LIBUSB_ERROR_NOT_FOUND so my setup does not seem to be ok :( :( :(, but at least it finds a device.

[pelikhan]

Thanks’