[gnome-boxes] installer-media: prepare() return true on success

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit ea755cb958ceed155ea3d06ac4b2f94e8f0cce54
Author: Lasse Schuirmann <lasse schuirmann gmail com>
Date:   Mon Oct 27 17:23:57 2014 +0100

    installer-media: prepare() return true on success
    
    This allows callers to handle cancellation/failure.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725386

 src/installer-media.vala      |    7 +++++--
 src/unattended-installer.vala |   25 +++++++++++++++++--------
 2 files changed, 22 insertions(+), 10 deletions(-)
---
diff --git a/src/installer-media.vala b/src/installer-media.vala
index a520b14..7a23cde 100644
--- a/src/installer-media.vala
+++ b/src/installer-media.vala
@@ -82,8 +82,11 @@ private class Boxes.InstallerMedia : GLib.Object {
     }
 
     public virtual void set_direct_boot_params (DomainOs os) {}
-    public virtual async void prepare (ActivityProgress progress = new ActivityProgress (),
-                                       Cancellable? cancellable = null) {}
+    // Returns true on success, false otherwise
+    public virtual async bool prepare (ActivityProgress progress = new ActivityProgress (),
+                                       Cancellable?     cancellable = null) {
+        return true;
+    }
     public virtual async void prepare_for_installation (string vm_name, Cancellable? cancellable) {}
     public virtual void prepare_to_continue_installation (string vm_name) {}
     public virtual void clean_up () {
diff --git a/src/unattended-installer.vala b/src/unattended-installer.vala
index 48116fe..87e4463 100644
--- a/src/unattended-installer.vala
+++ b/src/unattended-installer.vala
@@ -338,9 +338,9 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
         return get_user_pkgcache (filename);
     }
 
-    public override async void prepare (ActivityProgress progress = new ActivityProgress (),
-                                        Cancellable? cancellable = null) {
-        yield setup_drivers (progress, cancellable);
+    public override async bool prepare (ActivityProgress progress = new ActivityProgress (),
+                                        Cancellable?     cancellable = null) {
+        return yield setup_drivers (progress, cancellable);
     }
 
     private DomainDisk? get_unattended_disk_config (PathFormat path_format = PathFormat.UNIX) {
@@ -461,7 +461,7 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
 
     private delegate void AddUnattendedFileFunc (UnattendedFile file);
 
-    private async void setup_drivers (ActivityProgress progress, Cancellable? cancellable = null) {
+    private async bool setup_drivers (ActivityProgress progress, Cancellable? cancellable = null) {
         progress.info = _("Downloading device drivers…");
 
         var scripts = get_pre_installer_scripts ();
@@ -469,7 +469,8 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
 
         if (drivers.length () != 0 && scripts.length () != 0) {
             var drivers_progress = progress.add_child_activity (0.5);
-            yield setup_drivers_from_list (drivers, drivers_progress, add_unattended_file, cancellable);
+            if (!yield setup_drivers_from_list (drivers, drivers_progress, add_unattended_file, cancellable))
+                return false;
         } else
             progress.progress = 0.5;
 
@@ -478,12 +479,14 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
 
         if (drivers.length () != 0 && scripts.length () != 0) {
             var drivers_progress = progress.add_child_activity (0.5);
-            yield setup_drivers_from_list (drivers, drivers_progress, add_secondary_unattended_file, 
cancellable);
+            return yield setup_drivers_from_list (drivers, drivers_progress, add_secondary_unattended_file, 
cancellable);
         } else
             progress.progress = 1.0;
+
+        return true;
     }
 
-    private async void setup_drivers_from_list (GLib.List<DeviceDriver> drivers,
+    private async bool setup_drivers_from_list (GLib.List<DeviceDriver> drivers,
                                                 ActivityProgress        progress,
                                                 AddUnattendedFileFunc   add_func,
                                                 Cancellable?            cancellable = null) {
@@ -494,12 +497,18 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
             try {
                 yield setup_driver (driver, driver_progress, add_func, cancellable);
                 additional_devices.add_all (driver.get_devices ());
+            } catch (IOError.CANCELLED e) {
+                debug ("Media preparation cancelled during driver setup.");
+
+                return false;
             } catch (GLib.Error e) {
                 debug ("Failed to make use of drivers at '%s': %s", driver.get_location (), e.message);
             } finally {
                 driver_progress.progress = 1.0; // Ensure progress reaches 100%
             }
         }
+
+        return true;
     }
 
     private async void setup_driver (DeviceDriver          driver,
@@ -527,7 +536,7 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
                 cached_paths += system_cached_path;
 
             var file_progress = progress.add_child_activity (file_progress_scale);
-            file = yield downloader.download (file, cached_paths, file_progress);
+            file = yield downloader.download (file, cached_paths, file_progress, cancellable);
             file_progress.progress = 1.0; // Ensure progress reaches 100%
 
             driver_files.append (new UnattendedRawFile (this, file.get_path (), filename));