Added SDL_hid_get_properties()

Author: slouken

include/SDL3/SDL_hidapi.h

@@ -283,6 +283,23 @@ extern SDL_DECLSPEC SDL_hid_device * SDLCALL SDL_hid_open(unsigned short vendor_
  */
 extern SDL_DECLSPEC SDL_hid_device * SDLCALL SDL_hid_open_path(const char *path);
 
+/**
+ * Get the properties associated with an SDL_hid_device.
+ *
+ * The following read-only properties are provided by SDL:
+ *
+ * - `SDL_PROP_HIDAPI_LIBUSB_DEVICE_HANDLE_POINTER`: the libusb_device_handle associated with the device, if it was opened using libusb.
+ *
+ * \param dev a device handle returned from SDL_hid_open().
+ * \returns a valid property ID on success or 0 on failure; call
+ *          SDL_GetError() for more information.
+ *
+ * \since This function is available since SDL 3.4.0.
+ */
+extern SDL_DECLSPEC SDL_PropertiesID SDLCALL SDL_hid_get_properties(SDL_hid_device *dev);
+
+#define SDL_PROP_HIDAPI_LIBUSB_DEVICE_HANDLE_POINTER   "SDL.hidapi.libusb.device.handle"
+
 /**
  * Write an Output report to a HID device.
  *

src/hidapi/SDL_hidapi.c

@@ -960,13 +960,14 @@ struct SDL_hid_device
     void *device;
     const struct hidapi_backend *backend;
     SDL_hid_device_info info;
+    SDL_PropertiesID props;
 };
 
 #if defined(HAVE_PLATFORM_BACKEND) || defined(HAVE_DRIVER_BACKEND) || defined(HAVE_LIBUSB)
 
 static SDL_hid_device *CreateHIDDeviceWrapper(void *device, const struct hidapi_backend *backend)
 {
-    SDL_hid_device *wrapper = (SDL_hid_device *)SDL_malloc(sizeof(*wrapper));
+    SDL_hid_device *wrapper = (SDL_hid_device *)SDL_calloc(1, sizeof(*wrapper));
     SDL_SetObjectValid(wrapper, SDL_OBJECT_TYPE_HIDAPI_DEVICE, true);
     wrapper->device = device;
     wrapper->backend = backend;
@@ -1433,7 +1434,9 @@ SDL_hid_device *SDL_hid_open(unsigned short vendor_id, unsigned short product_id
     if (libusb_ctx) {
         pDevice = LIBUSB_hid_open(vendor_id, product_id, serial_number);
         if (pDevice != NULL) {
-            return CreateHIDDeviceWrapper(pDevice, &LIBUSB_Backend);
+            SDL_hid_device *dev = CreateHIDDeviceWrapper(pDevice, &LIBUSB_Backend);
+            SDL_SetPointerProperty(SDL_hid_get_properties(dev), SDL_PROP_HIDAPI_LIBUSB_DEVICE_HANDLE_POINTER, ((LIBUSB_hid_device *)pDevice)->device_handle);
+            return dev;
         }
     }
 #endif // HAVE_LIBUSB
@@ -1472,7 +1475,9 @@ SDL_hid_device *SDL_hid_open_path(const char *path)
     if (libusb_ctx) {
         pDevice = LIBUSB_hid_open_path(path);
         if (pDevice != NULL) {
-            return CreateHIDDeviceWrapper(pDevice, &LIBUSB_Backend);
+            SDL_hid_device *dev = CreateHIDDeviceWrapper(pDevice, &LIBUSB_Backend);
+            SDL_SetPointerProperty(SDL_hid_get_properties(dev), SDL_PROP_HIDAPI_LIBUSB_DEVICE_HANDLE_POINTER, ((LIBUSB_hid_device *)pDevice)->device_handle);
+            return dev;
         }
     }
 #endif // HAVE_LIBUSB
@@ -1482,6 +1487,16 @@ SDL_hid_device *SDL_hid_open_path(const char *path)
     return NULL;
 }
 
+SDL_PropertiesID SDL_hid_get_properties(SDL_hid_device *device)
+{
+    CHECK_DEVICE_MAGIC(device, 0);
+
+    if (!device->props) {
+        device->props = SDL_CreateProperties();
+    }
+    return device->props;
+}
+
 int SDL_hid_write(SDL_hid_device *device, const unsigned char *data, size_t length)
 {
     CHECK_DEVICE_MAGIC(device, -1);
@@ -1536,6 +1551,7 @@ int SDL_hid_close(SDL_hid_device *device)
     CHECK_DEVICE_MAGIC(device, -1);
 
     device->backend->hid_close(device->device);
+    SDL_DestroyProperties(device->props);
     DeleteHIDDeviceWrapper(device);
     return 0;
 }