[banshee] [Hardware.Gio] Implement support for IUsbdevice.ResolveRootUsbDevice

[Gabriel Burt <gburt src gnome org>]

commit d61618da902846524e4cf9323b405553c5d73f58
Author: Alan McGovern <alan mcgovern gmail com>
Date:   Sat Jul 24 16:21:06 2010 +0100

    [Hardware.Gio] Implement support for IUsbdevice.ResolveRootUsbDevice
    
    Add support for returning an IUsbDevice for a given IDevice.

 .../Banshee.Gio/Banshee.Hardware.Gio/Device.cs     |    2 +-
 .../Banshee.Gio/Banshee.Hardware.Gio/UsbDevice.cs  |   24 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)
---
diff --git a/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/Device.cs b/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/Device.cs
index 0095a20..8170bb6 100644
--- a/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/Device.cs
+++ b/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/Device.cs
@@ -81,7 +81,7 @@ namespace Banshee.Hardware.Gio
 
         public IUsbDevice ResolveRootUsbDevice ()
         {
-            return null;
+            return UsbDevice.ResolveRootDevice (this);
         }
 
         public bool PropertyExists (string key)
diff --git a/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/UsbDevice.cs b/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/UsbDevice.cs
index bcbc7af..316dd4a 100644
--- a/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/UsbDevice.cs
+++ b/src/Backends/Banshee.Gio/Banshee.Hardware.Gio/UsbDevice.cs
@@ -41,11 +41,33 @@ namespace Banshee.Hardware.Gio
         const string UdevVendorId = "ID_VENDOR_ID";
         const string UdevProductId = "ID_MODEL_ID";
 
-        public IUsbDevice ResolveRootUsbDevice ()
+        internal static IUsbDevice ResolveRootDevice (IDevice device)
         {
+            // First check if the supplied device is an IUsbDevice itself
+            var result = Resolve (device);
+            if (result != null) {
+                return result;
+            }
+
+            // Now walk up the device tree to see if we can find one.
+            IRawDevice raw = device as IRawDevice;
+            if (raw != null) {
+                var parent = raw.Device.UdevMetadata.Parent;
+                while (parent != null) {
+                    if (parent.PropertyExists (UdevUsbBusNumber) && parent.PropertyExists (UdevUsbDeviceNumber)) {
+                        return new UsbDevice (new RawUsbDevice (raw.Device.Manager, raw.Device.GioMetadata, parent));
+                    }
+                    parent = parent.Parent;
+                }
+            }
             return null;
         }
 
+        public IUsbDevice ResolveRootUsbDevice ()
+        {
+            return this;
+        }
+
         public static int GetBusNumber (IUsbDevice device)
         {
             var raw = device as IRawDevice;