[gnome-boxes] machine: Add cloning API

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 72a36c7be100517b82438b3d1c9502f83dcb4137
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Tue May 3 21:53:31 2016 +0100

    machine: Add cloning API
    
    Add abstract method clone() and abstract property can_clone. Currently
    this is not implemented by any Machine subclass, i-e can_clone property
    is set to false by all subclasses.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=710307

 src/libvirt-machine.vala |    3 +++
 src/machine.vala         |    2 ++
 src/ovirt-machine.vala   |    2 ++
 src/remote-machine.vala  |    3 +++
 4 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/src/libvirt-machine.vala b/src/libvirt-machine.vala
index 280b32b..295ef71 100644
--- a/src/libvirt-machine.vala
+++ b/src/libvirt-machine.vala
@@ -33,6 +33,7 @@ private class Boxes.LibvirtMachine: Boxes.Machine {
     public override bool suspend_at_exit { get { return connection == App.app.default_connection && 
!run_in_bg; } }
     public override bool can_save { get { return !saving && state != MachineState.SAVED && !importing; } }
     public override bool can_restart { get { return state == MachineState.RUNNING || state == 
MachineState.SAVED; } }
+    public override bool can_clone { get { return false; } }
     protected override bool should_autosave {
         get {
             return (base.should_autosave &&
@@ -681,6 +682,8 @@ private class Boxes.LibvirtMachine: Boxes.Machine {
         try_shutdown ();
     }
 
+    public override async void clone () {}
+
     public string? get_ip_address () {
         if (system_virt_connection == null || !is_on)
             return null;
diff --git a/src/machine.vala b/src/machine.vala
index 61f664f..5903200 100644
--- a/src/machine.vala
+++ b/src/machine.vala
@@ -16,6 +16,7 @@ private abstract class Boxes.Machine: Boxes.CollectionItem, Boxes.IPropertiesPro
 
     public virtual bool can_save { get { return false; } }
     public abstract bool can_restart { get; }
+    public abstract bool can_clone { get; }
     public bool can_delete { get; protected set; default = true; }
     public bool under_construction { get; protected set; default = false; }
 
@@ -359,6 +360,7 @@ private abstract class Boxes.Machine: Boxes.CollectionItem, Boxes.IPropertiesPro
 
     public abstract async void connect_display (ConnectFlags flags) throws GLib.Error;
     public abstract void restart ();
+    public abstract async void clone ();
 
     public virtual void disconnect_display () {
         if (display == null)
diff --git a/src/ovirt-machine.vala b/src/ovirt-machine.vala
index 807d1d0..20896ab 100644
--- a/src/ovirt-machine.vala
+++ b/src/ovirt-machine.vala
@@ -4,6 +4,7 @@ using Gtk;
 
 private class Boxes.OvirtMachine: Boxes.Machine {
     public override bool can_restart { get { return false; } }
+    public override bool can_clone { get { return false; } }
 
     private Ovirt.Vm vm;
     private Ovirt.Proxy proxy;
@@ -79,6 +80,7 @@ private class Boxes.OvirtMachine: Boxes.Machine {
     }
 
     public override void restart () {} // See FIXME on RemoteMachine.restart
+    public override async void clone () {}
 
     private void update_info () {
         var uri = Xml.URI.parse (source.uri);
diff --git a/src/remote-machine.vala b/src/remote-machine.vala
index 26809f5..6ff0e7c 100644
--- a/src/remote-machine.vala
+++ b/src/remote-machine.vala
@@ -3,6 +3,7 @@ using Gtk;
 
 private class Boxes.RemoteMachine: Boxes.Machine, Boxes.IPropertiesProvider {
     public override bool can_restart { get { return false; } }
+    public override bool can_clone { get { return false; } }
 
     public RemoteMachine (CollectionSource source) throws Boxes.Error {
         if (source.source_type != "spice" &&
@@ -99,6 +100,8 @@ private class Boxes.RemoteMachine: Boxes.Machine, Boxes.IPropertiesProvider {
     //        restart and this method is currently used for that purpose only.
     public override void restart () {}
 
+    public override async void clone () {}
+
     private void update_info () {
         var uri = Xml.URI.parse (source.uri);
         if (uri == null || uri.server == name) // By default server is chosen as name