// RegisterHotplugCallback registers a hotplug callback function. The callback will fire when
// a matching event occurs on a device matching vendorID, productID and class.
// HOTPLUG_ANY can be used to match any vendor ID, product ID or device class.
// If enumerate is true, the callback is called for matching currently attached devices.
// It returns a function that can be called to deregister the callback.
// Returning true from the callback will also deregister the callback.
// Closing the context will deregister all callbacks automatically.
func (c *Context) RegisterHotplugCallback(vendorID int, productID int, class int, enumerate bool, callback HotplugCallback, event HotplugEvent, events ...HotplugEvent) (func(), error) {
var handle hotplugHandle
data := hotplugCallbackData{
f: callback,
ctx: c,
}
// store the data in go memory, since we can't pass it to cgo.
dataID := callbacks.add(&data)
c.addCallback(dataID)
var enumflag C.libusb_hotplug_flag
if enumerate {
enumflag = 1
} else {
enumflag = 0
}
for _, e := range events {
event |= e
}
res := C.attachCallback(c.ctx, C.libusb_hotplug_event(event), enumflag, C.int(vendorID), C.int(productID), C.int(class), dataID, (*C.libusb_hotplug_callback_handle)(&handle))
if res != C.LIBUSB_SUCCESS {
callbacks.remove(dataID)
c.removeCallback(dataID)
return nil, usbError(res)
}
return func() {
C.libusb_hotplug_deregister_callback(c.ctx, C.libusb_hotplug_callback_handle(handle))
callbacks.remove(dataID)
c.removeCallback(dataID)
}, nil
}
func (ctx *Context) RegisterHotplugCallback(vendor_id int, product_id int, class int, callback HotplugCallback, events HotplugEvent, enumerate bool) (HotplugHandle, error) {
mutexHotplugCallbackMap.Lock()
defer mutexHotplugCallbackMap.Unlock()
var handle HotplugHandle
data := hotplugCallbackData{
f: callback,
}
dataPtr := unsafe.Pointer(&data)
var enumflag C.libusb_hotplug_flag
if enumerate {
enumflag = 1
} else {
enumflag = 0
}
res := C.attachCallback(ctx.ctx, C.libusb_hotplug_event(events), enumflag, C.int(vendor_id), C.int(product_id), C.int(class), dataPtr, (*C.libusb_hotplug_callback_handle)(&handle))
if res != C.LIBUSB_SUCCESS {
return 0, usbError(res)
}
data.h = handle
// protect the data from the garbage collector
hotplugCallbackMap[handle] = &data
return handle, nil
}