[polari] telepathyClient: Monitor gnome-shell's built-in chat client

[Florian Müllner <fmuellner src gnome org>]

commit 2cd26e82a209bd45400d1c7c9ad0a99613af2ff2
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Mar 10 23:25:51 2019 +0100

    telepathyClient: Monitor gnome-shell's built-in chat client
    
    We currently assume that notifications for private chats are handled
    by gnome-shell's chat integration, but that
    
     - is obviously only available on the GNOME desktop
    
     - has been optional for some time
    
    Before we can start handling notifications for private chats as well, we
    need to know when should do that. So as a first step, monitor the session
    bus for gnome-shell's built-in chat client.
    
    https://gitlab.gnome.org/GNOME/polari/issues/18

 flatpak/org.gnome.Polari.json |  1 +
 src/telepathyClient.js        | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
---
diff --git a/flatpak/org.gnome.Polari.json b/flatpak/org.gnome.Polari.json
index fd720f0..e588d6c 100644
--- a/flatpak/org.gnome.Polari.json
+++ b/flatpak/org.gnome.Polari.json
@@ -21,6 +21,7 @@
         "--talk-name=org.freedesktop.Telepathy.AccountManager",
         "--talk-name=org.freedesktop.Telepathy.ChannelDispatcher",
         "--talk-name=org.freedesktop.Telepathy.Connection.idle.irc.*",
+        "--talk-name=org.freedesktop.Telepathy.Client.GnomeShell.*",
         "--own-name=org.freedesktop.Telepathy.Client.TpGLibRequestAndHandle.*",
         /* Telepathy names owned by bundled services */
         "--own-name=org.freedesktop.Telepathy.AccountManager",
diff --git a/src/telepathyClient.js b/src/telepathyClient.js
index 35f9972..72646d3 100644
--- a/src/telepathyClient.js
+++ b/src/telepathyClient.js
@@ -6,6 +6,8 @@ const { AccountsMonitor } = imports.accountsMonitor;
 const { RoomManager } = imports.roomManager;
 const Utils = imports.utils;
 
+const SHELL_CLIENT_PREFIX = 'org.freedesktop.Telepathy.Client.GnomeShell';
+
 const SASLAuthenticationIface = '<node> \
 <interface name="org.freedesktop.Telepathy.Channel.Interface.SASLAuthentication"> \
 <method name="StartMechanismWithData"> \
@@ -131,6 +133,47 @@ class TelepathyClient extends Tp.BaseClient {
         });
         this._accountsMonitor = AccountsMonitor.getDefault();
         this._accountsMonitor.prepare(this._onPrepared.bind(this));
+
+        this._shellHandlesPrivateChats = false;
+
+        // Track whether gnome-shell's built-in chat client is
+        // running; unfortunately it uses :uniquify-name, so
+        // we cannot simply use Gio.watch_bus_name()
+        let conn = this._app.get_dbus_connection();
+        conn.signal_subscribe(
+            'org.freedesktop.DBus', /* sender */
+            'org.freedesktop.DBus', /* iface */
+            'NameOwnerChanged', /* member */
+            '/org/freedesktop/DBus', /* path */
+            SHELL_CLIENT_PREFIX, /* arg0 */
+            Gio.DBusSignalFlags.MATCH_ARG0_NAMESPACE,
+            (_conn, _sender, _path, _iface, _signal, params) => {
+                let [name_, oldOwner_, newOwner] = params.deep_unpack();
+                this._shellHandlesPrivateChats = (newOwner != '');
+            });
+
+        conn.call(
+            'org.freedesktop.DBus',
+            '/org/freedesktop/DBus',
+            'org.freedesktop.DBus',
+            'ListNames',
+            null, /* params */
+            new GLib.VariantType('(as)'),
+            Gio.DBusCallFlags.NONE,
+            -1,
+            null, /* cancellable */
+            (_o, res) => {
+                let names = [];
+
+                try {
+                    [names] = conn.call_finish(res).deep_unpack();
+                } catch (e) {
+                    debug(`Failed to list bus names: ${e}`);
+                }
+
+                this._shellHandlesPrivateChats =
+                    names.find(n => n.startsWith(SHELL_CLIENT_PREFIX)) != null;
+            });
     }
 
     _onPrepared() {