[gnome-boxes/wip/run-in-bg] portals: Add singleton to talk to xdg-desktop-portals

[Felipe Borges <felipeborges src gnome org>]

commit 6e1134475506aa283134cc62e003e8607f4f8c5e
Author: Felipe Borges <felipeborges gnome org>
Date:   Tue Dec 8 11:33:41 2020 +0100

    portals: Add singleton to talk to xdg-desktop-portals
    
    This is useful for us to center the xdg-desktop-portals handling in
    a single place.

 src/meson.build  |  1 +
 src/portals.vala | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)
---
diff --git a/src/meson.build b/src/meson.build
index 8ff0b135..aa45b773 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -78,6 +78,7 @@ vala_sources = [
   'notification.vala',
   'notificationbar.vala',
   'os-database.vala',
+  'portals.vala',
   'properties.vala',
   'properties-window.vala',
   'properties-page-widget.vala',
diff --git a/src/portals.vala b/src/portals.vala
new file mode 100644
index 00000000..b835bf06
--- /dev/null
+++ b/src/portals.vala
@@ -0,0 +1,60 @@
+// This file is part of GNOME Boxes. License: LGPLv2+
+
+namespace org.freedesktop.portal {
+    [DBus(name = "org.freedesktop.portal.Request")]
+    public interface Request : GLib.Object {
+        [DBus(name = "Close")]
+        public abstract void close () throws DBusError, IOError;
+
+        [DBus(name = "Response")]
+        public signal void response (uint response, GLib.HashTable<string, GLib.Variant> results);
+    }
+
+    [DBus(name = "org.freedesktop.portal.Background")]
+    public interface Background : GLib.Object {
+        [DBus(name = "RequestBackground")]
+        public abstract GLib.ObjectPath request_background (string parent_window, GLib.HashTable<string, 
GLib.Variant> options) throws DBusError, IOError;
+    }
+}
+
+private class Boxes.Portals : GLib.Object {
+    private static Portals portals;
+    public static Portals get_default () {
+        if (portals == null)
+            portals = new Portals ();
+
+        return portals;
+    }
+
+    private const string BUS_NAME = "org.freedesktop.portal.Desktop";
+    private const string OBJECT_PATH = "/org/freedesktop/portal/desktop";
+
+    public delegate void PortalRequestCallback (uint response, GLib.HashTable<string, GLib.Variant>? results 
= null);
+
+    private GLib.DBusConnection bus;
+
+    public async void request_to_run_in_background (owned PortalRequestCallback? callback = null) {
+        try {
+            debug ("Requesting to run in background");
+
+            if (bus == null)
+                bus = yield Bus.get(BusType.SESSION);
+
+            var background = yield bus.get_proxy<org.freedesktop.portal.Background>(BUS_NAME, OBJECT_PATH);
+            var options = new GLib.HashTable<string, GLib.Variant>(str_hash, str_equal);
+            options.insert ("reason", new GLib.Variant ("s", _("Boxes wants to run VM in background")));
+            var handle = background.request_background (Config.APPLICATION_ID, options);
+
+            var request = yield bus.get_proxy<org.freedesktop.portal.Request>(BUS_NAME, handle);
+            request.response.connect ((response, results) => {
+                debug ("Received request response from portal");
+
+                callback (response, null);
+            });
+
+            yield;
+        } catch (GLib.Error error) {
+            warning ("Failed to request to run in background: %s", error.message);
+        }
+    }
+}