path: root/src/volume-control-pulse.vala

/*
 * Copyright 2013 Canonical Ltd.
 * Copyright 2021 Robert Tari
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *      Alberto Ruiz <alberto.ruiz@canonical.com>
 *      Robert Tari <robert@tari.in>
 */

using PulseAudio;
using Notify;
using Gee;

public class VolumeControlPulse : VolumeControl
{
    private unowned PulseAudio.GLibMainLoop loop = null;

    private uint _reconnect_timer = 0;

    private PulseAudio.Context context;
    private bool   _mute = true;
    private VolumeControl.Volume _volume = new VolumeControl.Volume();
    private double _mic_volume = 0.0;

    /* Used by the pulseaudio stream restore extension */
    private DBusConnection _pconn;
    /* Need both the list and hash so we can retrieve the last known sink-input after
     * releasing the current active one (restoring back to the previous known role) */
    private Gee.ArrayList<uint32> _sink_input_list = new Gee.ArrayList<uint32> ();
    private HashMap<uint32, string> _sink_input_hash = new HashMap<uint32, string> ();
    private bool _pulse_use_stream_restore = false;
    private int32 _active_sink_input = -1;
    private string[] _valid_roles = {"multimedia", "alert", "alarm", "phone"};
    private string? _objp_role_multimedia = null;
    private string? _objp_role_alert = null;
    private string? _objp_role_alarm = null;
    private string? _objp_role_phone = null;
    private uint _pa_volume_sig_count = 0;

    private uint _local_volume_timer = 0;
    private uint _accountservice_volume_timer = 0;
    private bool _send_next_local_volume = false;
    private double _account_service_volume = 0.0;
    private VolumeControl.ActiveOutput _active_output = VolumeControl.ActiveOutput.SPEAKERS;
    private AccountsServiceAccess _accounts_service_access;
    private bool _external_mic_detected = false;
    private bool _source_sink_mic_activated = false;

    /** true when a microphone is active **/
    public override bool active_mic { get; set; default = false; }

    public VolumeControlPulse (IndicatorSound.Options options, PulseAudio.GLibMainLoop loop, AccountsServiceAccess? accounts_service_access)
    {
        base(options);

        _volume.volume = 0.0;
        _volume.reason = VolumeControl.VolumeReasons.PULSE_CHANGE;

        this.loop = loop;

        _accounts_service_access = accounts_service_access;
        this._accounts_service_access.notify["volume"].connect(() => {
            if (this._accounts_service_access.volume >= 0 && _account_service_volume != this._accounts_service_access.volume) {
                _account_service_volume = this._accounts_service_access.volume;
                // we need to wait for this to settle.
                start_account_service_volume_timer();
            }
        });
        this.reconnect_to_pulse ();
    }

    ~VolumeControlPulse ()
    {
        stop_all_timers();
    }

    private void stop_all_timers()
    {
        if (_reconnect_timer != 0) {
            Source.remove (_reconnect_timer);
            _reconnect_timer = 0;
        }
        stop_local_volume_timer();
        stop_account_service_volume_timer();
    }

    public static VolumeControl.ActiveOutput calculate_active_output (SinkInfo? sink) {

        VolumeControl.ActiveOutput ret_output = VolumeControl.ActiveOutput.SPEAKERS;
        /* Check if the current active port is headset/headphone */
            /* There is not easy way to check if the port is a headset/headphone besides
             * checking for the port name. On touch (with the pulseaudio droid element)
             * the headset/headphone port is called 'output-headset' and 'output-headphone'.
             * On the desktop this is usually called 'analog-output-headphones' */

        // first of all check if we are in call mode
        if (sink.active_port != null && sink.active_port.name == "output-speaker+wired_headphone") {
            return VolumeControl.ActiveOutput.CALL_MODE;
        }
        // look if it's a headset/headphones
        if (sink.name == "indicator_sound_test_headphones" ||
            (sink.active_port != null &&
             (sink.active_port.name.contains("headset") ||
                  sink.active_port.name.contains("headphone")))) {
                    // check if it's a bluetooth device
                    unowned string device_bus = sink.proplist.gets ("device.bus");
                    if (device_bus != null && device_bus == "bluetooth") {
                    ret_output = VolumeControl.ActiveOutput.BLUETOOTH_HEADPHONES;
                    } else if (device_bus != null && device_bus == "usb") {
                    ret_output = VolumeControl.ActiveOutput.USB_HEADPHONES;
                } else if (device_bus != null && device_bus == "hdmi") {
                    ret_output = VolumeControl.ActiveOutput.HDMI_HEADPHONES;
                } else {
                    ret_output = VolumeControl.ActiveOutput.HEADPHONES;
                }
        } else {
            // speaker
            unowned string device_bus = sink.proplist.gets ("device.bus");
                if (device_bus != null && device_bus == "bluetooth") {
                    ret_output = VolumeControl.ActiveOutput.BLUETOOTH_SPEAKER;
                } else if (device_bus != null && device_bus == "usb") {
                ret_output = VolumeControl.ActiveOutput.USB_SPEAKER;
            } else if (device_bus != null && device_bus == "hdmi") {
                ret_output = VolumeControl.ActiveOutput.HDMI_SPEAKER;
            } else {
                ret_output = VolumeControl.ActiveOutput.SPEAKERS;
                }
        }

        return ret_output;
    }

    private bool is_external_mic (SourceInfo? sink) {
        if (sink.name.contains ("indicator_sound_test_mic")) {
            return true;
        }
        if (sink.active_port != null &&
                ( (sink.active_port.name.contains ("headphone") ||
                   sink.active_port.name.contains ("headset") ||
                   sink.active_port.name.contains ("mic") ) &&
                  (!sink.active_port.name.contains ("internal") &&
                   !sink.active_port.name.contains ("builtin")) )) {
            return true;
        }
        return false;
    }


    /* PulseAudio logic*/
    private void context_events_cb (Context c, Context.SubscriptionEventType t, uint32 index)
    {
        switch (t & Context.SubscriptionEventType.FACILITY_MASK)
        {
            case Context.SubscriptionEventType.SINK:
                update_sink ();
                break;

            case Context.SubscriptionEventType.SINK_INPUT:
                switch (t & Context.SubscriptionEventType.TYPE_MASK)
                {
                    case Context.SubscriptionEventType.NEW:
                        c.get_sink_input_info (index, handle_new_sink_input_cb);
                        break;

                    case Context.SubscriptionEventType.CHANGE:
                        c.get_sink_input_info (index, handle_changed_sink_input_cb);
                        break;

                    case Context.SubscriptionEventType.REMOVE:
                        remove_sink_input_from_list (index);
                        break;
                    default:
                        debug ("Sink input event not known.");
                        break;
                }
                break;

            case Context.SubscriptionEventType.SOURCE:
                update_source ();
                break;

            case Context.SubscriptionEventType.SOURCE_OUTPUT:
                switch (t & Context.SubscriptionEventType.TYPE_MASK)
                {
                    case Context.SubscriptionEventType.NEW:
                        c.get_source_output_info (index, source_output_info_cb);
                        break;

                    case Context.SubscriptionEventType.REMOVE:
                        this._source_sink_mic_activated = false;
                        this.active_mic = _external_mic_detected;
                        break;
                    default:
                        break;
                }
                break;

            default:
                break;
        }
    }

    private void sink_info_cb_for_props (Context c, SinkInfo? i, int eol)
    {
        if (i == null)
            return;

        if (_mute != (bool)i.mute)
        {
            _mute = (bool)i.mute;
            this.notify_property ("mute");
        }

        var playing = (i.state == PulseAudio.SinkState.RUNNING);
        if (is_playing != playing)
            is_playing = playing;

        var oldval = _active_output;
        var newval = calculate_active_output(i);

        _active_output = newval;

        // Emit a change signal iff CALL_MODE wasn't involved. (FIXME: yuck.)
        if ((oldval != VolumeControl.ActiveOutput.CALL_MODE) &&
            (newval != VolumeControl.ActiveOutput.CALL_MODE) &&
            (oldval != newval)) {
            this.active_output_changed (newval);
        }

        if (_pulse_use_stream_restore == false &&
                _volume.volume != volume_to_double (i.volume.max ()))
        {
            var vol = new VolumeControl.Volume();
            vol.volume = volume_to_double (i.volume.max ());
            vol.reason = VolumeControl.VolumeReasons.PULSE_CHANGE;
            this.volume = vol;
        }
    }

    private void source_info_cb (Context c, SourceInfo? i, int eol)
    {
        if (i == null)
            return;

        if (is_external_mic (i)) {
            this.active_mic = true;
            _external_mic_detected = true;
        } else {
            this.active_mic = _source_sink_mic_activated;
            _external_mic_detected = false;
        }

        if (_mic_volume != volume_to_double (i.volume.values[0]))
        {
            _mic_volume = volume_to_double (i.volume.values[0]);
            this.notify_property ("mic-volume");
        }
    }

    private void server_info_cb_for_props (Context c, ServerInfo? i)
    {
        if (i == null)
            return;
        context.get_sink_info_by_name (i.default_sink_name, sink_info_cb_for_props);
    }

    private void update_sink ()
    {
        context.get_server_info (server_info_cb_for_props);
    }

    private void update_source_get_server_info_cb (PulseAudio.Context c, PulseAudio.ServerInfo? i) {
        if (i != null)
            context.get_source_info_by_name (i.default_source_name, source_info_cb);
    }

    private void update_source ()
    {
        context.get_server_info (update_source_get_server_info_cb);
    }

    private DBusMessage pulse_dbus_filter (DBusConnection connection, owned DBusMessage message, bool incoming)
    {
        if (message.get_message_type () == DBusMessageType.SIGNAL) {
            string active_role_objp = _objp_role_alert;
            if (_active_sink_input != -1)
                active_role_objp = _sink_input_hash.get (_active_sink_input);

            if (message.get_path () == active_role_objp && message.get_member () == "VolumeUpdated") {
                uint sig_count = 0;
                lock (_pa_volume_sig_count) {
                    sig_count = _pa_volume_sig_count;
                    if (_pa_volume_sig_count > 0)
                        _pa_volume_sig_count--;
                }

                /* We only care about signals if our internal count is zero */
                if (sig_count == 0) {
                    /* Extract volume and make sure it's not a side effect of us setting it */
                    Variant body = message.get_body ();
                    Variant varray = body.get_child_value (0);

                    uint32 type = 0, lvolume = 0;
                    VariantIter iter = varray.iterator ();
                    iter.next ("(uu)", &type, &lvolume);
                    /* Here we need to compare integer values to avoid rounding issues, so just
                     * using the volume values used by pulseaudio */
                    PulseAudio.Volume cvolume = double_to_volume (_volume.volume);
                    if (lvolume != cvolume) {
                        /* Someone else changed the volume for this role, reflect on the indicator */
                        var vol = new VolumeControl.Volume();
                        vol.volume = volume_to_double (lvolume);
                        vol.reason = VolumeControl.VolumeReasons.PULSE_CHANGE;
                        this.volume = vol;
                    }
                }
            }
        }

        return message;
    }

    private VolumeControl.Stream calculate_active_stream()
    {
        if (_active_sink_input != -1) {
            var path = _sink_input_hash[_active_sink_input];
            if (path == _objp_role_multimedia)
                return Stream.MULTIMEDIA;
            if (path == _objp_role_alarm)
                return Stream.ALARM;
            if (path == _objp_role_phone)
                return Stream.PHONE;
        }

        return VolumeControl.Stream.ALERT;
    }

    private async void update_active_sink_input (int32 index)
    {
        if ((index == -1) || (index != _active_sink_input && index in _sink_input_list)) {
            string sink_input_objp = _objp_role_alert;
            if (index != -1)
                sink_input_objp = _sink_input_hash.get (index);
            _active_sink_input = index;
            var stream = calculate_active_stream();
            if (active_stream != stream) {
                active_stream = stream;
            }

            /* Listen for role volume changes from pulse itself (external clients) */
            try {
                var builder = new VariantBuilder (VariantType.OBJECT_PATH_ARRAY);
                builder.add ("o", sink_input_objp);

                yield _pconn.call ("org.PulseAudio.Core1", "/org/pulseaudio/core1",
                        "org.PulseAudio.Core1", "ListenForSignal",
                        new Variant ("(sao)", "org.PulseAudio.Ext.StreamRestore1.RestoreEntry.VolumeUpdated", builder),
                        null, DBusCallFlags.NONE, -1);
            } catch (GLib.Error e) {
                warning ("unable to listen for pulseaudio dbus signals (%s)", e.message);
            }

            try {
                var props_variant = yield _pconn.call ("org.PulseAudio.Ext.StreamRestore1.RestoreEntry",
                        sink_input_objp, "org.freedesktop.DBus.Properties", "Get",
                        new Variant ("(ss)", "org.PulseAudio.Ext.StreamRestore1.RestoreEntry", "Volume"),
                        null, DBusCallFlags.NONE, -1);
                Variant tmp;
                props_variant.get ("(v)", out tmp);
                uint32 type = 0, volume = 0;
                VariantIter iter = tmp.iterator ();
                iter.next ("(uu)", &type, &volume);

                var vol = new VolumeControl.Volume();
                vol.volume = volume_to_double (volume);
                vol.reason = VolumeControl.VolumeReasons.VOLUME_STREAM_CHANGE;
                this.volume = vol;
            } catch (GLib.Error e) {
                warning ("unable to get volume for active role %s (%s)", sink_input_objp, e.message);
            }
        }
    }

    private void add_sink_input_into_list (SinkInputInfo sink_input)
    {
        /* We're only adding ones that are not corked and with a valid role */
        unowned string role = sink_input.proplist.gets (PulseAudio.Proplist.PROP_MEDIA_ROLE);

        if (role != null && role in _valid_roles) {
            if (sink_input.corked == 0 || role == "phone") {
                _sink_input_list.insert (0, sink_input.index);
                switch (role)
                {
                    case "multimedia":
                        _sink_input_hash.set (sink_input.index, _objp_role_multimedia);
                        break;
                    case "alert":
                        _sink_input_hash.set (sink_input.index, _objp_role_alert);
                        break;
                    case "alarm":
                        _sink_input_hash.set (sink_input.index, _objp_role_alarm);
                        break;
                    case "phone":
                        _sink_input_hash.set (sink_input.index, _objp_role_phone);
                        break;
                }
                /* Only switch the active sink input in case a phone one is not active */
                if (_active_sink_input == -1 ||
                        _sink_input_hash.get (_active_sink_input) != _objp_role_phone)
                    update_active_sink_input.begin ((int32)sink_input.index);
            }
        }
    }

    private void remove_sink_input_from_list (uint32 index)
    {
        if (index in _sink_input_list) {
            _sink_input_list.remove (index);
            _sink_input_hash.unset (index);
            if (index == _active_sink_input) {
                if (_sink_input_list.size != 0)
                    update_active_sink_input.begin ((int32)_sink_input_list.get (0));
                else
                    update_active_sink_input.begin (-1);
            }
        }
    }

    private void handle_new_sink_input_cb (Context c, SinkInputInfo? i, int eol)
    {
        if (i == null)
            return;

        add_sink_input_into_list (i);
    }

    private void handle_changed_sink_input_cb (Context c, SinkInputInfo? i, int eol)
    {
        if (i == null)
            return;

        if (i.index in _sink_input_list) {
            /* Phone stream is always corked, so handle it differently */
            if (i.corked == 1 && _sink_input_hash.get (i.index) != _objp_role_phone)
                remove_sink_input_from_list (i.index);
        } else {
            if (i.corked == 0)
                add_sink_input_into_list (i);
        }
    }

    private void source_output_info_cb (Context c, SourceOutputInfo? i, int eol)
    {
        if (i == null)
            return;

        unowned string role = i.proplist.gets (PulseAudio.Proplist.PROP_MEDIA_ROLE);
        if (role == "phone" || role == "production") {
            this.active_mic = true;
            this._source_sink_mic_activated = true;
        }
    }

    private void context_state_callback (Context c)
    {
        switch (c.get_state ()) {
            case Context.State.READY:
                if (_pulse_use_stream_restore) {
                    c.subscribe (PulseAudio.Context.SubscriptionMask.SINK |
                            PulseAudio.Context.SubscriptionMask.SINK_INPUT |
                            PulseAudio.Context.SubscriptionMask.SOURCE |
                            PulseAudio.Context.SubscriptionMask.SOURCE_OUTPUT);
                } else {
                    c.subscribe (PulseAudio.Context.SubscriptionMask.SINK |
                            PulseAudio.Context.SubscriptionMask.SOURCE |
                            PulseAudio.Context.SubscriptionMask.SOURCE_OUTPUT);
                }
                c.set_subscribe_callback (context_events_cb);
                update_sink ();
                update_source ();
                this.ready = true; // true because we're connected to the pulse server
                break;

            case Context.State.FAILED:
            case Context.State.TERMINATED:
                if (_reconnect_timer == 0)
                    _reconnect_timer = Timeout.add_seconds (2, reconnect_timeout);
                break;

            default:
                this.ready = false;
                break;
        }
    }

    bool reconnect_timeout ()
    {
        _reconnect_timer = 0;
        reconnect_to_pulse ();
        return Source.REMOVE;
    }

    void reconnect_to_pulse ()
    {
        if (this.ready) {
            this.context.disconnect ();
            this.context = null;
            this.ready = false;
        }

                /* FIXME: Ubuntu Settings Daemon specifics */
        var props = new Proplist ();
        props.sets (Proplist.PROP_APPLICATION_NAME, "Ubuntu Audio Settings");
        props.sets (Proplist.PROP_APPLICATION_ID, "com.canonical.settings.sound");
        props.sets (Proplist.PROP_APPLICATION_ICON_NAME, "multimedia-volume-control");
        props.sets (Proplist.PROP_APPLICATION_VERSION, "0.1");

        reconnect_pulse_dbus ();

        this.context = new PulseAudio.Context (loop.get_api(), null, props);
        this.context.set_state_callback (context_state_callback);

        unowned string server_string = Environment.get_variable("PULSE_SERVER");
        if (context.connect(server_string, Context.Flags.NOFAIL, null) < 0)
            warning( "pa_context_connect() failed: %s\n", PulseAudio.strerror(context.errno()));
    }

    void sink_info_list_callback_set_mute (PulseAudio.Context context, PulseAudio.SinkInfo? sink, int eol) {
        if (sink != null)
            context.set_sink_mute_by_index (sink.index, true, null);
    }

    void sink_info_list_callback_unset_mute (PulseAudio.Context context, PulseAudio.SinkInfo? sink, int eol) {
        if (sink != null)
            context.set_sink_mute_by_index (sink.index, false, null);
    }

    /* Mute operations */
    bool set_mute_internal (bool mute)
    {
        return_val_if_fail (context.get_state () == Context.State.READY, false);

        if (_mute != mute) {
            if (mute)
                context.get_sink_info_list (sink_info_list_callback_set_mute);
            else
                context.get_sink_info_list (sink_info_list_callback_unset_mute);
            return true;
        } else {
            return false;
        }
    }

    public override void set_mute (bool mute)
    {
        if (set_mute_internal (mute))
            _accounts_service_access.mute = mute;
    }

    public void toggle_mute ()
    {
        this.set_mute (!this._mute);
    }

    public override bool mute
    {
        get
        {
            return this._mute;
        }
    }

    public override VolumeControl.ActiveOutput active_output()
    {
        return _active_output;
    }

    /* Volume operations */
    public static PulseAudio.Volume double_to_volume (double vol)
    {
        double tmp = (double)(PulseAudio.Volume.NORM - PulseAudio.Volume.MUTED) * vol;
        return (PulseAudio.Volume)tmp + PulseAudio.Volume.MUTED;
    }

    public static double volume_to_double (PulseAudio.Volume vol)
    {
        double tmp = (double)(vol - PulseAudio.Volume.MUTED);
        return tmp / (double)(PulseAudio.Volume.NORM - PulseAudio.Volume.MUTED);
    }

    private void set_volume_success_cb (Context c, int success)
    {
        if ((bool)success)
            this.notify_property("volume");
    }

    private void sink_info_set_volume_cb (Context c, SinkInfo? i, int eol)
    {
        if (i == null)
            return;

        unowned CVolume cvol = i.volume;
        cvol.scale (double_to_volume (_volume.volume));
        c.set_sink_volume_by_index (i.index, cvol, set_volume_success_cb);
    }

    private void server_info_cb_for_set_volume (Context c, ServerInfo? i)
    {
        if (i == null)
        {
            warning ("Could not get PulseAudio server info");
            return;
        }

        context.get_sink_info_by_name (i.default_sink_name, sink_info_set_volume_cb);
    }

    private async void set_volume_active_role ()
    {
        string active_role_objp = _objp_role_alert;

        if (_active_sink_input != -1 && _active_sink_input in _sink_input_list)
            active_role_objp = _sink_input_hash.get (_active_sink_input);

        try {
            double vol = _volume.volume;
            var builder = new VariantBuilder (new VariantType ("a(uu)"));
            builder.add ("(uu)", 0, double_to_volume (vol));
            Variant volume = builder.end ();

            /* Increase the signal counter so we can handle the callback */
            lock (_pa_volume_sig_count) {
                _pa_volume_sig_count++;
            }

            yield _pconn.call ("org.PulseAudio.Ext.StreamRestore1.RestoreEntry",
                    active_role_objp, "org.freedesktop.DBus.Properties", "Set",
                    new Variant ("(ssv)", "org.PulseAudio.Ext.StreamRestore1.RestoreEntry", "Volume", volume),
                    null, DBusCallFlags.NONE, -1);
        } catch (GLib.Error e) {
            lock (_pa_volume_sig_count) {
                _pa_volume_sig_count--;
            }
            warning ("unable to set volume for stream obj path %s (%s)", active_role_objp, e.message);
        }
    }

    void set_mic_volume_success_cb (Context c, int success)
    {
        if ((bool)success)
            this.notify_property ("mic-volume");
    }

    void set_mic_volume_get_server_info_cb (PulseAudio.Context c, PulseAudio.ServerInfo? i) {
        if (i != null) {
            unowned CVolume cvol = CVolume ();
            cvol.set (1, double_to_volume (_mic_volume));
            c.set_source_volume_by_name (i.default_source_name, cvol, set_mic_volume_success_cb);
        }
    }

    public override VolumeControl.Volume volume {
        get {
            return _volume;
        }
        set {
            var volume_changed = (value.volume != _volume.volume);
            debug("Setting volume to %f for profile %d because %d", value.volume, _active_sink_input, value.reason);

            _volume = value;

            /* Make sure we're connected to Pulse and pulse didn't give us the change */
            if (context.get_state () == Context.State.READY &&
                    _volume.reason != VolumeControl.VolumeReasons.PULSE_CHANGE &&
                    volume_changed)
                if (_pulse_use_stream_restore)
                    set_volume_active_role.begin ();
                else
                    context.get_server_info (server_info_cb_for_set_volume);


            if (volume.reason != VolumeControl.VolumeReasons.ACCOUNTS_SERVICE_SET
                && volume_changed) {
                start_local_volume_timer();
            }
        }
    }

    /** MIC VOLUME PROPERTY */

    public override double mic_volume {
        get {
            return _mic_volume;
        }
        set {
            return_if_fail (context.get_state () == Context.State.READY);

            _mic_volume = value;

            context.get_server_info (set_mic_volume_get_server_info_cb);
        }
    }

    public static DBusConnection? create_pulse_dbus_connection()
    {
        unowned string pulse_dbus_server_env = Environment.get_variable ("PULSE_DBUS_SERVER");
        string address;

        if (pulse_dbus_server_env != null) {
            address = pulse_dbus_server_env;
        } else {
            DBusConnection conn;
            Variant props;

            try {
                conn = Bus.get_sync (BusType.SESSION);
            } catch (GLib.IOError e) {
                warning ("unable to get the dbus session bus: %s", e.message);
                return null;
            }

            try {
                var props_variant = conn.call_sync ("org.PulseAudio1",
                        "/org/pulseaudio/server_lookup1", "org.freedesktop.DBus.Properties",
                        "Get", new Variant ("(ss)", "org.PulseAudio.ServerLookup1", "Address"),
                        null, DBusCallFlags.NONE, -1);
                props_variant.get ("(v)", out props);
                address = props.get_string ();
            } catch (GLib.Error e) {
                warning ("unable to get pulse unix socket: %s", e.message);
                return null;
            }
        }

        DBusConnection conn = null;
        try {
            conn = new DBusConnection.for_address_sync (address, DBusConnectionFlags.AUTHENTICATION_CLIENT);
        } catch (GLib.Error e) {
            GLib.warning("Unable to connect to dbus server at '%s': %s", address, e.message);
            /* If it fails, it means the dbus pulse extension is not available */
        }
        GLib.debug ("PulseAudio dbus address is '%s', connection is '%p'", address, conn);
        return conn;
    }

    /* PulseAudio Dbus (Stream Restore) logic */
    private void reconnect_pulse_dbus ()
    {
        /* In case of a reconnect */
        _pulse_use_stream_restore = false;
        _pa_volume_sig_count = 0;

        _pconn = create_pulse_dbus_connection();
        if (_pconn == null)
            return;

        /* For pulse dbus related events */
        _pconn.add_filter (pulse_dbus_filter);

        /* Check if the 4 currently supported media roles are already available in StreamRestore
         * Roles: multimedia, alert, alarm and phone */
        _objp_role_multimedia = stream_restore_get_object_path (_pconn, "sink-input-by-media-role:multimedia");
        _objp_role_alert = stream_restore_get_object_path (_pconn, "sink-input-by-media-role:alert");
        _objp_role_alarm = stream_restore_get_object_path (_pconn, "sink-input-by-media-role:alarm");
        _objp_role_phone = stream_restore_get_object_path (_pconn, "sink-input-by-media-role:phone");

        /* Only use stream restore if every used role is available */
        if (_objp_role_multimedia != null && _objp_role_alert != null && _objp_role_alarm != null && _objp_role_phone != null) {
            debug ("Using PulseAudio DBUS Stream Restore module");
            /* Restore volume and update default entry */
            update_active_sink_input.begin (-1);
            _pulse_use_stream_restore = true;
        }
    }

    public static string? stream_restore_get_object_path (DBusConnection pconn, string name) {
        string? objp = null;
        try {
            Variant props_variant = pconn.call_sync ("org.PulseAudio.Ext.StreamRestore1",
                    "/org/pulseaudio/stream_restore1", "org.PulseAudio.Ext.StreamRestore1",
                    "GetEntryByName", new Variant ("(s)", name), null, DBusCallFlags.NONE, -1);
            /* Workaround for older versions of vala that don't provide get_objv */
            VariantIter iter = props_variant.iterator ();
            iter.next ("o", &objp);
            debug ("Found obj path %s for restore data named %s\n", objp, name);
        } catch (GLib.Error e) {
            debug ("unable to find stream restore data for: %s. Error: %s", name, e.message);
        }
        return objp;
    }

    /* AccountsService operations */

    private void start_local_volume_timer()
    {
        // perform a slow sync with the accounts service. max at 1 per second.

        // stop the AS update timer, as since we're going to be setting the volume.
        stop_account_service_volume_timer();

        if (_local_volume_timer == 0) {
            _accounts_service_access.volume = _volume.volume;
            _local_volume_timer = Timeout.add_seconds (1, local_volume_changed_timeout);
        } else {
            _send_next_local_volume = true;
        }
    }

    private void stop_local_volume_timer()
    {
        if (_local_volume_timer != 0) {
            Source.remove (_local_volume_timer);
            _local_volume_timer = 0;
        }
    }

    bool local_volume_changed_timeout()
    {
        _local_volume_timer = 0;
        if (_send_next_local_volume) {
            _send_next_local_volume = false;
            start_local_volume_timer ();
        }
        return Source.REMOVE;
    }

    private void start_account_service_volume_timer()
    {
        if (_accountservice_volume_timer == 0) {
            // If we haven't been messing with local volume recently, apply immediately.
            if (_local_volume_timer == 0) {
                var vol = new VolumeControl.Volume();
                vol.volume = _account_service_volume;
                vol.reason = VolumeControl.VolumeReasons.ACCOUNTS_SERVICE_SET;
                this.volume = vol;
                return;
            }
            // Else check again in another second if needed.
            // (if AS is throwing us lots of notifications, we update at most once a second)
            _accountservice_volume_timer = Timeout.add_seconds (1, accountservice_volume_changed_timeout);
        }
    }

    private void stop_account_service_volume_timer()
    {
        if (_accountservice_volume_timer != 0) {
            Source.remove (_accountservice_volume_timer);
            _accountservice_volume_timer = 0;
        }
    }

    bool accountservice_volume_changed_timeout ()
    {
        _accountservice_volume_timer = 0;
        start_account_service_volume_timer ();
        return Source.REMOVE;
    }
}