feat(mobile): Synthesize device.class based on specs from device context

[edwardgou-sentry]

Adds and uses normalize_device_context which creates a new device.class context value by checking a combination of the device family, processor_frequency, processor_count, and memory_size.

The device.class context value will be used in the sentry issues, performance, and discover products for the device classification project (getsentry/sentry#44449).

[jan-auer]

Thanks for the contribution!

[jan-auer]

You can avoid these unwraps with an if let statement similar to the one above:

Suggested change

	} else if device.processor_frequency.value().is_some()
	&& device.processor_count.value().is_some()
	&& device.memory_size.value().is_some()
	{
	if device.processor_frequency.value().unwrap() < &2000
	|| device.memory_size.value().unwrap() < &(4 * GIB)
	|| device.processor_count.value().unwrap() < &8
	{
	device.class = Annotated::new(DEVICE_CLASS_LOW);
	} else if device.processor_frequency.value().unwrap() < &2500
	|| device.memory_size.value().unwrap() < &(6 * GIB)
	{
	device.class = Annotated::new(DEVICE_CLASS_MEDIUM);
	} else {
	device.class = Annotated::new(DEVICE_CLASS_HIGH);
	}
	}
	} else if let (Some(&freq), Some(&proc), Some(&mem)) = (
	device.processor_frequency.value(),
	device.processor_count.value(),
	device.memory_size.value(),
	) {
	if freq < 2000 || mem < 4 * GIB || proc < 8 {
	device.class = Annotated::new(DEVICE_CLASS_LOW);
	} else if freq < 2500 || mem < 6 * GIB {
	device.class = Annotated::new(DEVICE_CLASS_MEDIUM);
	} else {
	device.class = Annotated::new(DEVICE_CLASS_HIGH);
	}
	}

[edwardgou-sentry]

👍 Thanks Jan, updated to if let!

[jan-auer]

Since the device class is an enumeration with semantic values, can we make it an enum instead? For instance, what should happen when an SDK sends the value 42?

If you want to allow any number, you can introduce a so-called "newtype":

#[derive(Clone, Copy, Debug, Deserialize, Eq, PartialEq Serialize)]
struct DeviceClass(pub u64);

impl DeviceClass {
    const LOW: Self = Self(1);
    const MEDIUM: Self = Self(2);
    const HIGH: Self = Self(3);
}

// use as `DeviceClass::LOW`

[edwardgou-sentry]

Hey Jan, I went with the newtype that you suggested!
We have plans to support more device class values in the future and theres use in being able to compare the number values so I think this works best for us.

[jan-auer]

This will allow clients to send unknown device class values, which we will store without modification. If this is OK for the rest of the product, this PR can be merged.