path: root/module-volume-change-notify.c

/***
  Volume Change Notification Module for PulseAudio
  Copyright 2012 Alexander Sulfrian

  This module is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published
  by the Free Software Foundation; either version 2.1 of the License,
  or (at your option) any later version.

  This module 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 Lesser General Public License
  along with PulseAudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#include <config.h>

#include <pulsecore/module.h>
#include <pulsecore/core-subscribe.h>
#include <pulse/introspect.h>

#include <dbus/dbus.h>

PA_MODULE_AUTHOR("Alexander Sulfrian");
PA_MODULE_DESCRIPTION("Send DBus signals on volume change.");
PA_MODULE_VERSION(PACKAGE_VERSION);
PA_MODULE_USAGE("");

struct userdata {
    pa_core *core;
    pa_module *module;
    pa_subscription *subscription;

    /* dbus stuff */
    DBusError dbus_error;
    DBusConnection *dbus_connection;
};

dbus_bool_t add_volumes(DBusMessageIter *args, const pa_cvolume *vol)
{
    DBusMessageIter array;
    char buf[] = { DBUS_TYPE_UINT16, 0};
    const pa_volume_t *values;
    uint8_t channel;

    if (!dbus_message_iter_open_container (args, DBUS_TYPE_ARRAY,
                                           buf, &array))
        return FALSE;

    for (channel = 0; channel < vol->channels; channel++) {
        uint16_t volume = (vol->values[channel] * 100 + PA_VOLUME_NORM / 2) /
            PA_VOLUME_NORM;

        if (!dbus_message_iter_append_basic(&array, DBUS_TYPE_UINT16,
                                            &volume)) {
            dbus_message_iter_abandon_container (args, &array);
            return FALSE;
        }
    }

    if (!dbus_message_iter_close_container (args, &array))
        return FALSE;

    return TRUE;
}

void send_dbus_signal(const char *name, const pa_cvolume *vol,
                      const struct userdata *u)
{
    DBusMessage* msg;
    DBusMessageIter args;

    /* create a signal and check for errors */
    msg = dbus_message_new_signal("/org/PulseAudio/VolumeNotification",
                                  "org.PulseAudio.VolumeNotification",
                                  "VolumeChange");
    if (!msg)
        return;

    /* append arguments onto signal */
    dbus_message_iter_init_append(msg, &args);
    if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &name))
        goto fail;

    if (!add_volumes(&args, vol))
        goto fail;

    /* send the message and flush the connection */
    if (!dbus_connection_send(u->dbus_connection, msg, NULL))
        goto fail;

    dbus_connection_flush(u->dbus_connection);

fail:
    /* free the message */
    dbus_message_unref(msg);
}

void sink_change_event_cb(pa_core *c, pa_subscription_event_type_t t,
                          uint32_t idx, void *userdata)
{
    pa_sink *s;

    if (PA_SUBSCRIPTION_EVENT_CHANGE & t == 0)
        return;

    if (!userdata)
        return;

    s = pa_idxset_get_by_index(c->sinks, idx);
    if (!s)
        return;

    send_dbus_signal(s->name, &s->reference_volume, userdata);
}

void pa__done(pa_module *m)
{
    struct userdata *u;

    if (!(u = m->userdata))
        return;

    pa_subscription_free(u->subscription);

    if (u->dbus_connection)
        dbus_connection_close(u->dbus_connection);

    pa_xfree(u);
}

int pa__init(pa_module* m)
{
    struct userdata *u;
    pa_subscription_mask_t mask;
    int ret;

    m->userdata = u = pa_xnew0(struct userdata, 1);
    u->core = m->core;
    u->module = m;

    mask = PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT | PA_SUBSCRIPTION_EVENT_CHANGE;
    u->subscription = pa_subscription_new(m->core, mask,
                                          sink_change_event_cb, u);

    /* initialize dbus */
    dbus_error_init(&u->dbus_error);
    u->dbus_connection = dbus_bus_get(DBUS_BUS_SESSION, &u->dbus_error);
    if (dbus_error_is_set(&u->dbus_error)) {
        pa_log("DBus Connection Error (%s)\n", u->dbus_error.message);
        dbus_error_free(&u->dbus_error);
    }

    if (!u->dbus_connection)
        goto fail;

    /* request a name on the bus */
    ret = dbus_bus_request_name(u->dbus_connection,
                                "org.PulseAudio.VolumeNotification",
                                DBUS_NAME_FLAG_REPLACE_EXISTING,
                                &u->dbus_error);

    if (dbus_error_is_set(&u->dbus_error)) {
        pa_log("DBus Name Error (%s)\n", u->dbus_error.message);
        dbus_error_free(&u->dbus_error);
    }

    if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
        goto fail;
    }

    return 0;

fail:
    pa__done(m);
    return -1;
}