[gnome-boxes] libvirt-machine-props: Allow shrinking volume in wizard

[Fabiano Fidêncio <ffidencio src gnome org>]

commit a6aecaea51a7ae1fca3024738d1873db104c1a30
Author: Fabiano Fidêncio <fidencio redhat com>
Date:   Wed Mar 12 19:49:36 2014 +0100

    libvirt-machine-props: Allow shrinking volume in wizard
    
    As the disk format used by Boxes (qcow2) doesn't support shrinking,
    lets implement it by deleting the existing storage volume and creating
    a new one using the disk size set by the user, when the user is
    creating a new VM.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=700374

 src/libvirt-machine-properties.vala |   43 +++++++++++++++++++++++++++++++++-
 src/os-database.vala                |    8 ++++++
 2 files changed, 49 insertions(+), 2 deletions(-)
---
diff --git a/src/libvirt-machine-properties.vala b/src/libvirt-machine-properties.vala
index 4f534ea..7e697cf 100644
--- a/src/libvirt-machine-properties.vala
+++ b/src/libvirt-machine-properties.vala
@@ -466,7 +466,7 @@ private class Boxes.LibvirtMachineProperties: GLib.Object, Boxes.IPropertiesProv
             var property = add_size_property (ref list,
                                               _("Maximum Disk Size"),
                                               volume_info.capacity,
-                                              volume_info.capacity,
+                                              get_minimum_disk_size (),
                                               pool_info.available,
                                               256 * MEGABYTES);
             // Disable 'save on timeout' all together since that could lead us to very bad user experience:
@@ -517,7 +517,7 @@ private class Boxes.LibvirtMachineProperties: GLib.Object, Boxes.IPropertiesProv
                         });
                     }
                 } else {
-                    machine.storage_volume.resize (value, StorageVolResizeFlags.NONE);
+                    resize_storage_volume (value);
                     debug ("Storage changed to %llu", value);
                 }
             } catch (GLib.Error error) {
@@ -530,4 +530,43 @@ private class Boxes.LibvirtMachineProperties: GLib.Object, Boxes.IPropertiesProv
             return false;
         };
     }
+
+    private uint64 get_minimum_disk_size () throws GLib.Error {
+        var volume_info = machine.storage_volume.get_info ();
+        if (machine.vm_creator == null) {
+            // Since we disable the properties during install going on we don't need to check for
+            // previous_ui_state here to be WIZARD.
+            return volume_info.capacity;
+        }
+
+        Osinfo.Resources minimum_resources = null;
+
+        if (machine.vm_creator.install_media.os != null) {
+            var os = machine.vm_creator.install_media.os;
+            var architecture = machine.domain_config.get_os ().get_arch ();
+            minimum_resources = OSDatabase.get_minimum_resources_for_os (os, architecture);
+        }
+
+        if (minimum_resources != null) {
+            return minimum_resources.storage;
+        } else {
+            var default_resources = OSDatabase.get_default_resources ();
+            return uint64.min (volume_info.capacity, default_resources.storage);
+        }
+    }
+
+    private void resize_storage_volume (uint64 size) throws GLib.Error {
+        var volume_info = machine.storage_volume.get_info ();
+        if (machine.vm_creator != null && size < volume_info.capacity) {
+            // New VM Customization
+            var config = machine.storage_volume.get_config (GVir.DomainXMLFlags.NONE);
+            config.set_capacity (size);
+            machine.storage_volume.delete (0);
+
+            var pool = get_storage_pool (machine.connection);
+            machine.storage_volume = pool.create_volume (config);
+        } else {
+            machine.storage_volume.resize (size, StorageVolResizeFlags.NONE);
+        }
+    }
 }
diff --git a/src/os-database.vala b/src/os-database.vala
index 2d57331..e2f311b 100644
--- a/src/os-database.vala
+++ b/src/os-database.vala
@@ -176,6 +176,14 @@ private class Boxes.OSDatabase : GLib.Object {
         return get_prefered_resources (list, prefs);
     }
 
+    public static Resources? get_minimum_resources_for_os (Os os, string architecture) {
+        string[] prefs = { architecture, ARCHITECTURE_ALL };
+
+        var list = os.get_minimum_resources ();
+
+        return get_prefered_resources (list, prefs);
+    }
+
     private Resources get_resources_from_os_resources (Resources? minimum, Resources? recommended) {
         var resources = get_default_resources ();