[Spice-devel] [spice-gtk 2/2] win-usb-dev: Use 'stable' libusb_device pointers in GUdevClient::udev_list

[Christophe Fergeau]

When getting a new list of USB devices after a WM_DEVICECHANGE event,
libusb_device which were already present before the event may be
represented by a different instance than the one we got in the new list.

Since other layers of spice-gtk may be using that older instance of
libusb_device, this commit makes sure that we always keep the older
instance in GUdevClient::udev_list.

At the moment, this should not be making any difference, but will make
things more consistent later on.

Based on a patch from Yuri Benditovich.

Signed-off-by: Christophe Fergeau <cfergeau at redhat.com>
---

Code is a bit longer this way, but imo it makes more sense to modify the
list when it's being updated, rather than modifying it during
notification.


 src/win-usb-dev.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/win-usb-dev.c b/src/win-usb-dev.c
index 192ab17f..a16bd3ae 100644
--- a/src/win-usb-dev.c
+++ b/src/win-usb-dev.c
@@ -423,6 +423,25 @@ static gint compare_libusb_devices(gconstpointer a, gconstpointer b)
     return (same_bus && same_addr && same_vid && same_pid) ? 0 : -1;
 }
 
+static void update_device_list(GUdevClient *self, GList *new_device_list)
+{
+    GList *dev;
+
+    for (dev = g_list_first(new_device_list); dev != NULL; dev = g_list_next(dev)) {
+        GList *found = g_list_find_custom(self->priv->udev_list, dev->data, compare_libusb_devices);
+        if (found != NULL) {
+            /* keep old existing libusb_device in the new list, when
+               usb-dev-manager will maintain its own list of libusb_device,
+               these lists will be completely consistent */
+            libusb_unref_device(dev->data);
+            dev->data = libusb_ref_device(found->data);
+        }
+    }
+
+    g_udev_client_free_device_list(&self->priv->udev_list);
+    self->priv->udev_list = new_device_list;
+}
+
 static void notify_dev_state_change(GUdevClient *self,
                                     GList *old_list,
                                     GList *new_list,
@@ -469,8 +488,7 @@ static void handle_dev_change(GUdevClient *self)
     notify_dev_state_change(self, now_devs, priv->udev_list, TRUE);
 
     /* keep most recent info: free previous list, and keep current list */
-    g_udev_client_free_device_list(&priv->udev_list);
-    priv->udev_list = now_devs;
+    update_device_list(self, now_devs);
 }
 
 static LRESULT CALLBACK wnd_proc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)
-- 
2.21.0