Special-case the generic pens for libwacom_get_supported_styli

The three generic pens have a vendor-id of 0 so let's special case those
for the now-deprecated API.

libwacom/libwacom.c

@@ -1600,6 +1600,14 @@ libwacom_stylus_get_for_id (const WacomDeviceDatabase *db, int tool_id)
 		.tool_id = tool_id,
 	};
 
+	switch (tool_id) {
+	case GENERIC_PEN_WITH_ERASER:
+	case GENERIC_ERASER:
+	case GENERIC_PEN_NO_ERASER:
+		id.vid = 0;
+		break;
+
+	}
 	return libwacom_stylus_get_for_stylus_id (db, &id);
 }
 

libwacom/libwacomint.h

@@ -42,6 +42,12 @@
 #define WACOM_DEVICE_INTEGRATED_UNSET (WACOM_DEVICE_INTEGRATED_NONE - 1U)
 #define WACOM_VENDOR_ID 0x056a
 
+enum GenericStylus {
+	GENERIC_PEN_WITH_ERASER = 0xfffff,
+        GENERIC_ERASER = 0xffffe,
+        GENERIC_PEN_NO_ERASER = 0xffffd,
+};
+
 enum WacomFeature {
 	FEATURE_STYLUS		= (1 << 0),
 	FEATURE_TOUCH		= (1 << 1),

test/__init__.py

@@ -196,8 +196,8 @@ def instance(cls):
         _Api(name="libwacom_get_num_keys", args=(c_void_p,), return_type=c_int),
         _Api(
             name="libwacom_get_supported_styli",
-            args=(c_void_p, c_void_p),
-            return_type=c_void_p,
+            args=(c_void_p, ctypes.POINTER(c_int)),
+            return_type=ctypes.POINTER(c_int),
         ),
         _Api(
             name="libwacom_get_styli",
@@ -558,6 +558,11 @@ class WacomEraserType(enum.IntEnum):
 
 
 class WacomStylus:
+    class Generic(enum.IntEnum):
+        PEN_WITH_ERASER = 0xFFFFF
+        ERASER = 0xFFFFE
+        PEN_NO_ERASER = 0xFFFFD
+
     def __init__(self, stylus):
         self.stylus = stylus
         lib = LibWacom.instance()

test/test_libwacom.py

@@ -5,6 +5,7 @@
 from configparser import ConfigParser
 from dataclasses import dataclass, field
 
+import ctypes
 import logging
 import pytest
 
@@ -15,6 +16,7 @@
     WacomDevice,
     WacomEraserType,
     WacomStatusLed,
+    WacomStylus,
 )
 
 logger = logging.getLogger(__name__)
@@ -281,6 +283,32 @@ def test_isdv4_4800(db):
     assert device.num_buttons == 0
 
 
+@pytest.mark.parametrize(
+    "usbid,expected",
+    [
+        [(0x256C, 0x0067), [WacomStylus.Generic.PEN_NO_ERASER]],
+        [
+            (0x04F3, 0x264C),
+            [
+                WacomStylus.Generic.PEN_WITH_ERASER,
+                WacomStylus.Generic.ERASER,
+                WacomStylus.Generic.PEN_NO_ERASER,
+            ],
+        ],
+    ],
+)
+def test_generic_pens(db, usbid, expected):
+    # Inspiroy 2 has a generic-pen-no-eraser
+    device = db.new_from_usbid(*usbid)
+    assert device is not None
+
+    nstyli = ctypes.c_int()
+    styli = device.get_supported_styli(ctypes.byref(nstyli))
+    s = [WacomStylus.Generic(id) for id in styli[: nstyli.value]]
+
+    assert sorted(s) == sorted(expected)
+
+
 @pytest.mark.parametrize(
     "bus,vid,pid",
     [