[gnome-boxes] Add Display.should_keep_alive()

[Alexander Larsson <alexl src gnome org>]

commit d23082d9e477f0acaaac88da24ece1e8dc60527c
Author: Alexander Larsson <alexl redhat com>
Date:   Fri Nov 9 11:50:36 2012 +0100

    Add Display.should_keep_alive()
    
    This returns true if the connection needs to be alive even
    when not visible. ATM it returns true for spice displays that
    have USB devices connected.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=672268

 src/display.vala       |    4 ++++
 src/spice-display.vala |   20 ++++++++++++++++++++
 2 files changed, 24 insertions(+), 0 deletions(-)
---
diff --git a/src/display.vala b/src/display.vala
index 4e19237..3c76bec 100644
--- a/src/display.vala
+++ b/src/display.vala
@@ -22,6 +22,10 @@ private abstract class Boxes.Display: GLib.Object, Boxes.IPropertiesProvider {
     public abstract void set_enable_inputs (Gtk.Widget widget, bool enable);
     public abstract void set_enable_audio (bool enable);
 
+    public virtual bool should_keep_alive () {
+        return false;
+    }
+
     public abstract void connect_it () throws GLib.Error;
     public abstract void disconnect_it ();
 
diff --git a/src/spice-display.vala b/src/spice-display.vala
index c125c21..1ff2b1a 100644
--- a/src/spice-display.vala
+++ b/src/spice-display.vala
@@ -14,6 +14,7 @@ private class Boxes.SpiceDisplay: Boxes.Display {
     private BoxConfig.SyncProperty[] display_sync_properties;
     private BoxConfig.SyncProperty[] gtk_session_sync_properties;
     private bool connected;
+    private bool closed;
 
     public bool resize_guest { get; set; }
     private void ui_state_changed () {
@@ -101,6 +102,24 @@ private class Boxes.SpiceDisplay: Boxes.Display {
         return display;
     }
 
+    private bool has_usb_device_connected () {
+        try {
+            var manager = UsbDeviceManager.get (session);
+            var devs = manager.get_devices ();
+            for (int i = 0; i < devs.length; i++) {
+                var dev = devs[i];
+                if (manager.is_device_connected (dev))
+                    return true;
+            }
+        } catch (GLib.Error error) {
+        }
+        return false;
+    }
+
+    public override bool should_keep_alive () {
+        return !closed && has_usb_device_connected ();
+    }
+
     public override void set_enable_audio (bool enable) {
         session.enable_audio = enable;
     }
@@ -175,6 +194,7 @@ private class Boxes.SpiceDisplay: Boxes.Display {
     private void main_event (ChannelEvent event) {
         switch (event) {
         case ChannelEvent.CLOSED:
+            closed = true;
             disconnected ();
             break;