gusb-device: drop g_usb_device_get_descriptor

We are using the contents of the descriptor in various log / GError messages,
so just make sure we have it from the start. We can do this since on
windows and Mac OS X libusb_get_device_descriptor never fails, and on
Linux it will only fail if the device was unplugged since enumerating,
in which case a g_warning will be printed.

Since we create the GUsbDevice on a udev event, the chances of it being
unplugged again already are very very small. And in case it is, we will
simply end up with all 0's in the device descriptor, returning 0x0000
for vid/pid just like before.

In the future this means we will also return 0 for the number of available
configs, which is a problem for apps who actually want to try to do
something with descriptors, but given that this only happens on unplugged
devices it is once more not a real issue since any (to be implemented)
g_usb_device_get_config_descriptor would fail on an unplugged device anyways.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

4 files changed, 7 insertions, 71 deletions

diff --git a/gusb/gusb-device-list.c b/gusb/gusb-device-list.c
index e432986..ea03a95 100644
--- a/gusb/gusb-device-list.c
+++ b/gusb/gusb-device-list.c
@@ -449,16 +449,11 @@ g_usb_device_list_find_by_vid_pid (GUsbDeviceList	*list,
 {
 	GUsbDeviceListPrivate *priv = list->priv;
 	GUsbDevice *device = NULL;
-	gboolean ret;
 	guint i;
 
 	for (i = 0; i < priv->devices->len; i++) {
 		GUsbDevice *curr = g_ptr_array_index (priv->devices, i);
 
-		/* get descriptor details */
-		ret = g_usb_device_get_descriptor (curr, error);
-		if (!ret)
-			goto out;
 		if (g_usb_device_get_vid (curr) == vid &&
 		    g_usb_device_get_pid (curr) == pid) {
 			device = g_object_ref (curr);
diff --git a/gusb/gusb-device.c b/gusb/gusb-device.c
index 0511b9d..7ee8f23 100644
--- a/gusb/gusb-device.c
+++ b/gusb/gusb-device.c
@@ -53,7 +53,6 @@ struct _GUsbDevicePrivate
 	GUsbContext		*context;
 	libusb_device		*device;
 	libusb_device_handle	*handle;
-	gboolean		 has_descriptor;
 	struct libusb_device_descriptor desc;
 };
 
@@ -104,45 +103,6 @@ g_usb_device_get_property (GObject		*object,
 	}
 }
 
-/**
- * g_usb_device_get_descriptor:
- * @device: a #GUsbDevice
- * @error: a #GError, or %NULL
- *
- * Gets the USB descriptor for the device.
- *
- * Return value: %TRUE on success
- *
- * Since: 0.1.0
- **/
-gboolean
-g_usb_device_get_descriptor (GUsbDevice *device, GError **error)
-{
-	int r;
-	gboolean ret = TRUE;
-	GUsbDevicePrivate *priv = device->priv;
-
-	g_return_val_if_fail (G_USB_IS_DEVICE (device), FALSE);
-
-	/* already got */
-	if (priv->has_descriptor)
-		goto out;
-
-	r = libusb_get_device_descriptor (priv->device, &priv->desc);
-	if (r < 0) {
-		ret = FALSE;
-		g_set_error (error,
-			     G_USB_DEVICE_ERROR,
-			     G_USB_DEVICE_ERROR_INTERNAL,
-			     "Failed to get USB descriptor for device: %s",
-			     gusb_strerror (r));
-		goto out;
-	}
-	priv->has_descriptor = TRUE;
-out:
-	return ret;
-}
-
 static gboolean
 g_usb_device_libusb_error_to_gerror (GUsbDevice *device,
 				     gint rc,
@@ -1133,6 +1093,7 @@ g_usb_device_constructor (GType			 gtype,
 	GObject *obj;
 	GUsbDevice *device;
 	GUsbDevicePrivate *priv;
+	gint rc;
 
 	{
 		/* Always chain up to the parent constructor */
@@ -1150,6 +1111,11 @@ g_usb_device_constructor (GType			 gtype,
 
 	libusb_ref_device(priv->device);
 
+	rc = libusb_get_device_descriptor (priv->device, &priv->desc);
+	if (rc != LIBUSB_SUCCESS)
+		g_warning ("Failed to get USB descriptor for device: %s",
+			   gusb_strerror (rc));
+
 	return obj;
 }
 
@@ -1283,9 +1249,6 @@ g_usb_device_get_address (GUsbDevice *device)
  *
  * Gets the vendor ID for the device.
  *
- * If g_usb_device_get_descriptor() has never been called, then this
- * function will return with 0x0000.
- *
  * Return value: an ID.
  *
  * Since: 0.1.0
@@ -1293,8 +1256,6 @@ g_usb_device_get_address (GUsbDevice *device)
 guint16
 g_usb_device_get_vid (GUsbDevice *device)
 {
-	if (!device->priv->has_descriptor)
-		return 0x0000;
 	return device->priv->desc.idVendor;
 }
 
@@ -1304,9 +1265,6 @@ g_usb_device_get_vid (GUsbDevice *device)
  *
  * Gets the product ID for the device.
  *
- * If g_usb_device_get_descriptor() has never been called, then this
- * function will return with 0x0000.
- *
  * Return value: an ID.
  *
  * Since: 0.1.0
@@ -1314,7 +1272,5 @@ g_usb_device_get_vid (GUsbDevice *device)
 guint16
 g_usb_device_get_pid (GUsbDevice *device)
 {
-	if (!device->priv->has_descriptor)
-		return 0x0000;
 	return device->priv->desc.idProduct;
 }
diff --git a/gusb/gusb-device.h b/gusb/gusb-device.h
index f10a9c0..82e624f 100644
--- a/gusb/gusb-device.h
+++ b/gusb/gusb-device.h
@@ -113,8 +113,7 @@ GQuark			 g_usb_device_error_quark	(void);
 
 guint8			 g_usb_device_get_bus		(GUsbDevice	*device);
 guint8			 g_usb_device_get_address	(GUsbDevice	*device);
-gboolean		 g_usb_device_get_descriptor	(GUsbDevice	*device,
-							 GError		**error);
+
 guint16			 g_usb_device_get_vid		(GUsbDevice	*device);
 guint16			 g_usb_device_get_pid		(GUsbDevice	*device);
 
diff --git a/gusb/gusb-self-test.c b/gusb/gusb-self-test.c
index 81df02f..14d65c0 100644
--- a/gusb/gusb-self-test.c
+++ b/gusb/gusb-self-test.c
@@ -67,7 +67,6 @@ gusb_source_func (void)
 static void
 gusb_device_func (void)
 {
-	gboolean ret;
 	GError *error = NULL;
 	GPtrArray *array;
 	GUsbContext *ctx;
@@ -89,19 +88,6 @@ gusb_device_func (void)
 	g_assert_cmpint (array->len, >, 0);
 	device = G_USB_DEVICE (g_ptr_array_index (array, 0));
 
-	g_assert_cmpint (g_usb_device_get_vid (device), ==, 0x0000);
-	g_assert_cmpint (g_usb_device_get_pid (device), ==, 0x0000);
-
-	/* get descriptor once */
-	ret = g_usb_device_get_descriptor (device, &error);
-	g_assert_no_error (error);
-	g_assert (ret);
-
-	/* get descriptor again */
-	ret = g_usb_device_get_descriptor (device, &error);
-	g_assert_no_error (error);
-	g_assert (ret);
-
 	g_assert_cmpint (g_usb_device_get_vid (device), >, 0x0000);
 	g_assert_cmpint (g_usb_device_get_pid (device), >, 0x0000);