Generate the device class if not explicitly given in the tablet file

libwacom_get_class() is deprecated but it's still a part of the API, and
thus have required even new .tablet files to fill this out even though
it's superseded by IntegratedIn. So let's generate them programmatically.

This turns devices that are IntegratedIn=Display to the Cintiq class,
IntegratedIn=Display;System into the ISDV4 class, and everything else
into the Bamboo class (because Bamboo is not expected to have tool
ids/serials).

data/wacom-cintiq-24hd-touch.tablet

@@ -44,7 +44,6 @@ Name=Wacom Cintiq 24HD touch
 ModelName=DTH-2400
 DeviceMatch=usb|056a|00f8
 PairedID=usb|056a|00f6
-Class=Cintiq
 Width=21
 Height=13
 Layout=wacom-cintiq-24hd.svg

data/wacom-cintiq-27hdt.tablet

@@ -9,7 +9,6 @@ Name=Wacom Cintiq 27QHD touch
 ModelName=DTH-2700
 DeviceMatch=usb|056a|032b
 PairedID=usb|056a|032c
-Class=Cintiq
 Width=24
 Height=12
 Styli=@intuos5;@propengen2;

libwacom/libwacom.c

@@ -1364,7 +1364,20 @@ libwacom_get_height(const WacomDevice *device)
 LIBWACOM_EXPORT WacomClass
 libwacom_get_class(const WacomDevice *device)
 {
-	return device->cls;
+	if (device->cls != WCLASS_UNKNOWN) {
+		return device->cls;
+	}
+
+	switch (device->integration_flags) {
+	case WACOM_DEVICE_INTEGRATED_DISPLAY:
+		return WCLASS_CINTIQ;
+	case WACOM_DEVICE_INTEGRATED_DISPLAY|WACOM_DEVICE_INTEGRATED_SYSTEM:
+		return WCLASS_CINTIQ;
+	case WACOM_DEVICE_INTEGRATED_REMOTE:
+		return WCLASS_REMOTE;
+	}
+
+	return WCLASS_BAMBOO;
 }
 
 LIBWACOM_EXPORT int

test/test-load.c

@@ -202,6 +202,10 @@ test_cintiq24hdt(struct fixture *f, gconstpointer user_data)
 	const WacomMatch *match;
 
 	g_assert_nonnull(device);
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+	g_assert_cmpint(libwacom_get_class(device), ==, WCLASS_CINTIQ);
+#pragma GCC diagnostic pop
 
 	/* 24HDT has one paired device */
 	match = libwacom_get_paired_device(device);