/***
  This file is part of PulseAudio.

  Copyright 2008 Lennart Poettering
  Copyright 2009 Tanu Kaskinen

  PulseAudio 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.

  PulseAudio 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, see <http://www.gnu.org/licenses/>.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>

#include <pulse/gccmacro.h>
#include <pulse/xmalloc.h>
#include <pulse/volume.h>
#include <pulse/timeval.h>
#include <pulse/rtclock.h>

#include <pulsecore/core-error.h>
#include <pulsecore/module.h>
#include <pulsecore/core-util.h>
#include <pulsecore/modargs.h>
#include <pulsecore/log.h>
#include <pulsecore/core-subscribe.h>
#include <pulsecore/sink-input.h>
#include <pulsecore/source-output.h>
#include <pulsecore/namereg.h>
#include <pulsecore/protocol-native.h>
#include <pulsecore/pstream.h>
#include <pulsecore/pstream-util.h>
#include <pulsecore/database.h>
#include <pulsecore/tagstruct.h>
#include <pulsecore/proplist-util.h>

#ifdef HAVE_DBUS
#include <pulsecore/dbus-util.h>
#include <pulsecore/protocol-dbus.h>
#endif

PA_MODULE_AUTHOR("Lennart Poettering");
PA_MODULE_DESCRIPTION("Automatically restore the volume/mute/device state of streams");
PA_MODULE_VERSION(PACKAGE_VERSION);
PA_MODULE_LOAD_ONCE(true);
PA_MODULE_USAGE(
        "restore_device=<Save/restore sinks/sources?> "
        "restore_volume=<Save/restore volumes?> "
        "restore_muted=<Save/restore muted states?> "
        "on_hotplug=<This argument is obsolete, please remove it from configuration> "
        "on_rescue=<This argument is obsolete, please remove it from configuration> "
        "fallback_table=<filename>");

#define SAVE_INTERVAL (10 * PA_USEC_PER_SEC)
#define IDENTIFICATION_PROPERTY "module-stream-restore.id"

#define DEFAULT_FALLBACK_FILE PA_DEFAULT_CONFIG_DIR"/stream-restore.table"
#define DEFAULT_FALLBACK_FILE_USER "stream-restore.table"

#define WHITESPACE "\n\r \t"

static const char* const valid_modargs[] = {
    "restore_device",
    "restore_volume",
    "restore_muted",
    "on_hotplug",
    "on_rescue",
    "fallback_table",
    NULL
};

struct userdata {
    pa_core *core;
    pa_module *module;
    pa_subscription *subscription;
    pa_hook_slot
        *sink_input_new_hook_slot,
        *sink_input_fixate_hook_slot,
        *source_output_new_hook_slot,
        *source_output_fixate_hook_slot,
        *connection_unlink_hook_slot;
    pa_time_event *save_time_event;
    pa_database* database;

    bool restore_device:1;
    bool restore_volume:1;
    bool restore_muted:1;

    pa_native_protocol *protocol;
    pa_idxset *subscribed;

#ifdef HAVE_DBUS
    pa_dbus_protocol *dbus_protocol;
    pa_hashmap *dbus_entries;
    uint32_t next_index; /* For generating object paths for entries. */
#endif
};

#define ENTRY_VERSION 2

struct entry {
    bool muted_valid, volume_valid, device_valid, card_valid;
    bool muted;
    pa_channel_map channel_map;
    pa_cvolume volume;
    char* device;
    char* card;
};

enum {
    SUBCOMMAND_TEST,
    SUBCOMMAND_READ,
    SUBCOMMAND_WRITE,
    SUBCOMMAND_DELETE,
    SUBCOMMAND_SUBSCRIBE,
    SUBCOMMAND_EVENT
};

static struct entry* entry_new(void);
static void entry_free(struct entry *e);
static struct entry *entry_read(struct userdata *u, const char *name);
static bool entry_write(struct userdata *u, const char *name, const struct entry *e, bool replace);
static struct entry* entry_copy(const struct entry *e);
static void entry_apply(struct userdata *u, const char *name, struct entry *e);
static void trigger_save(struct userdata *u);

#ifdef HAVE_DBUS

#define OBJECT_PATH "/org/pulseaudio/stream_restore1"
#define ENTRY_OBJECT_NAME "entry"
#define INTERFACE_STREAM_RESTORE "org.PulseAudio.Ext.StreamRestore1"
#define INTERFACE_ENTRY INTERFACE_STREAM_RESTORE ".RestoreEntry"

#define DBUS_INTERFACE_REVISION 0

struct dbus_entry {
    struct userdata *userdata;

    char *entry_name;
    uint32_t index;
    char *object_path;
};

static void handle_get_interface_revision(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_get_entries(DBusConnection *conn, DBusMessage *msg, void *userdata);

static void handle_get_all(DBusConnection *conn, DBusMessage *msg, void *userdata);

static void handle_add_entry(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_get_entry_by_name(DBusConnection *conn, DBusMessage *msg, void *userdata);

static void handle_entry_get_index(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_entry_get_name(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_entry_get_device(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_entry_set_device(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, void *userdata);
static void handle_entry_get_volume(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_entry_set_volume(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, void *userdata);
static void handle_entry_get_mute(DBusConnection *conn, DBusMessage *msg, void *userdata);
static void handle_entry_set_mute(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, void *userdata);

static void handle_entry_get_all(DBusConnection *conn, DBusMessage *msg, void *userdata);

static void handle_entry_remove(DBusConnection *conn, DBusMessage *msg, void *userdata);

enum property_handler_index {
    PROPERTY_HANDLER_INTERFACE_REVISION,
    PROPERTY_HANDLER_ENTRIES,
    PROPERTY_HANDLER_MAX
};

enum entry_property_handler_index {
    ENTRY_PROPERTY_HANDLER_INDEX,
    ENTRY_PROPERTY_HANDLER_NAME,
    ENTRY_PROPERTY_HANDLER_DEVICE,
    ENTRY_PROPERTY_HANDLER_VOLUME,
    ENTRY_PROPERTY_HANDLER_MUTE,
    ENTRY_PROPERTY_HANDLER_MAX
};

static pa_dbus_property_handler property_handlers[PROPERTY_HANDLER_MAX] = {
    [PROPERTY_HANDLER_INTERFACE_REVISION] = { .property_name = "InterfaceRevision", .type = "u",  .get_cb = handle_get_interface_revision, .set_cb = NULL },
    [PROPERTY_HANDLER_ENTRIES]            = { .property_name = "Entries",           .type = "ao", .get_cb = handle_get_entries,            .set_cb = NULL }
};

static pa_dbus_property_handler entry_property_handlers[ENTRY_PROPERTY_HANDLER_MAX] = {
    [ENTRY_PROPERTY_HANDLER_INDEX]    = { .property_name = "Index",   .type = "u",     .get_cb = handle_entry_get_index,    .set_cb = NULL },
    [ENTRY_PROPERTY_HANDLER_NAME]     = { .property_name = "Name",    .type = "s",     .get_cb = handle_entry_get_name,     .set_cb = NULL },
    [ENTRY_PROPERTY_HANDLER_DEVICE]   = { .property_name = "Device",  .type = "s",     .get_cb = handle_entry_get_device,   .set_cb = handle_entry_set_device },
    [ENTRY_PROPERTY_HANDLER_VOLUME]   = { .property_name = "Volume",  .type = "a(uu)", .get_cb = handle_entry_get_volume,   .set_cb = handle_entry_set_volume },
    [ENTRY_PROPERTY_HANDLER_MUTE]     = { .property_name = "Mute",    .type = "b",     .get_cb = handle_entry_get_mute,     .set_cb = handle_entry_set_mute }
};

enum method_handler_index {
    METHOD_HANDLER_ADD_ENTRY,
    METHOD_HANDLER_GET_ENTRY_BY_NAME,
    METHOD_HANDLER_MAX
};

enum entry_method_handler_index {
    ENTRY_METHOD_HANDLER_REMOVE,
    ENTRY_METHOD_HANDLER_MAX
};

static pa_dbus_arg_info add_entry_args[] = { { "name",              "s",     "in" },
                                             { "device",            "s",     "in" },
                                             { "volume",            "a(uu)", "in" },
                                             { "mute",              "b",     "in" },
                                             { "apply_immediately", "b",     "in" },
                                             { "entry",             "o",     "out" } };
static pa_dbus_arg_info get_entry_by_name_args[] = { { "name", "s", "in" }, { "entry", "o", "out" } };

static pa_dbus_method_handler method_handlers[METHOD_HANDLER_MAX] = {
    [METHOD_HANDLER_ADD_ENTRY] = {
        .method_name = "AddEntry",
        .arguments = add_entry_args,
        .n_arguments = sizeof(add_entry_args) / sizeof(pa_dbus_arg_info),
        .receive_cb = handle_add_entry },
    [METHOD_HANDLER_GET_ENTRY_BY_NAME] = {
        .method_name = "GetEntryByName",
        .arguments = get_entry_by_name_args,
        .n_arguments = sizeof(get_entry_by_name_args) / sizeof(pa_dbus_arg_info),
        .receive_cb = handle_get_entry_by_name }
};

static pa_dbus_method_handler entry_method_handlers[ENTRY_METHOD_HANDLER_MAX] = {
    [ENTRY_METHOD_HANDLER_REMOVE] = {
        .method_name = "Remove",
        .arguments = NULL,
        .n_arguments = 0,
        .receive_cb = handle_entry_remove }
};

enum signal_index {
    SIGNAL_NEW_ENTRY,
    SIGNAL_ENTRY_REMOVED,
    SIGNAL_MAX
};

enum entry_signal_index {
    ENTRY_SIGNAL_DEVICE_UPDATED,
    ENTRY_SIGNAL_VOLUME_UPDATED,
    ENTRY_SIGNAL_MUTE_UPDATED,
    ENTRY_SIGNAL_MAX
};

static pa_dbus_arg_info new_entry_args[]     = { { "entry", "o", NULL } };
static pa_dbus_arg_info entry_removed_args[] = { { "entry", "o", NULL } };

static pa_dbus_arg_info entry_device_updated_args[] = { { "device", "s",     NULL } };
static pa_dbus_arg_info entry_volume_updated_args[] = { { "volume", "a(uu)", NULL } };
static pa_dbus_arg_info entry_mute_updated_args[]   = { { "muted",  "b",     NULL } };

static pa_dbus_signal_info signals[SIGNAL_MAX] = {
    [SIGNAL_NEW_ENTRY]     = { .name = "NewEntry",     .arguments = new_entry_args,     .n_arguments = 1 },
    [SIGNAL_ENTRY_REMOVED] = { .name = "EntryRemoved", .arguments = entry_removed_args, .n_arguments = 1 }
};

static pa_dbus_signal_info entry_signals[ENTRY_SIGNAL_MAX] = {
    [ENTRY_SIGNAL_DEVICE_UPDATED] = { .name = "DeviceUpdated", .arguments = entry_device_updated_args, .n_arguments = 1 },
    [ENTRY_SIGNAL_VOLUME_UPDATED] = { .name = "VolumeUpdated", .arguments = entry_volume_updated_args, .n_arguments = 1 },
    [ENTRY_SIGNAL_MUTE_UPDATED]   = { .name = "MuteUpdated",   .arguments = entry_mute_updated_args,   .n_arguments = 1 }
};

static pa_dbus_interface_info stream_restore_interface_info = {
    .name = INTERFACE_STREAM_RESTORE,
    .method_handlers = method_handlers,
    .n_method_handlers = METHOD_HANDLER_MAX,
    .property_handlers = property_handlers,
    .n_property_handlers = PROPERTY_HANDLER_MAX,
    .get_all_properties_cb = handle_get_all,
    .signals = signals,
    .n_signals = SIGNAL_MAX
};

static pa_dbus_interface_info entry_interface_info = {
    .name = INTERFACE_ENTRY,
    .method_handlers = entry_method_handlers,
    .n_method_handlers = ENTRY_METHOD_HANDLER_MAX,
    .property_handlers = entry_property_handlers,
    .n_property_handlers = ENTRY_PROPERTY_HANDLER_MAX,
    .get_all_properties_cb = handle_entry_get_all,
    .signals = entry_signals,
    .n_signals = ENTRY_SIGNAL_MAX
};

static struct dbus_entry *dbus_entry_new(struct userdata *u, const char *entry_name) {
    struct dbus_entry *de;

    pa_assert(u);
    pa_assert(entry_name);
    pa_assert(*entry_name);

    de = pa_xnew(struct dbus_entry, 1);
    de->userdata = u;
    de->entry_name = pa_xstrdup(entry_name);
    de->index = u->next_index++;
    de->object_path = pa_sprintf_malloc("%s/%s%u", OBJECT_PATH, ENTRY_OBJECT_NAME, de->index);

    pa_assert_se(pa_dbus_protocol_add_interface(u->dbus_protocol, de->object_path, &entry_interface_info, de) >= 0);

    return de;
}

static void dbus_entry_free(struct dbus_entry *de) {
    pa_assert(de);

    pa_assert_se(pa_dbus_protocol_remove_interface(de->userdata->dbus_protocol, de->object_path, entry_interface_info.name) >= 0);

    pa_xfree(de->entry_name);
    pa_xfree(de->object_path);
    pa_xfree(de);
}

/* Reads an array [(UInt32, UInt32)] from the iterator. The struct items are
 * are a channel position and a volume value, respectively. The result is
 * stored in the map and vol arguments. The iterator must point to a "a(uu)"
 * element. If the data is invalid, an error reply is sent and a negative
 * number is returned. In case of a failure we make no guarantees about the
 * state of map and vol. In case of an empty array the channels field of both
 * map and vol are set to 0. This function calls dbus_message_iter_next(iter)
 * before returning. */
static int get_volume_arg(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, pa_channel_map *map, pa_cvolume *vol) {
    DBusMessageIter array_iter;
    DBusMessageIter struct_iter;
    char *signature;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(iter);
    pa_assert(map);
    pa_assert(vol);

    pa_assert_se(signature = dbus_message_iter_get_signature(iter));
    pa_assert(pa_streq(signature, "a(uu)"));

    dbus_free(signature);

    pa_channel_map_init(map);
    pa_cvolume_init(vol);

    map->channels = 0;
    vol->channels = 0;

    dbus_message_iter_recurse(iter, &array_iter);

    while (dbus_message_iter_get_arg_type(&array_iter) != DBUS_TYPE_INVALID) {
        dbus_uint32_t chan_pos;
        dbus_uint32_t chan_vol;

        dbus_message_iter_recurse(&array_iter, &struct_iter);

        dbus_message_iter_get_basic(&struct_iter, &chan_pos);

        if (chan_pos >= PA_CHANNEL_POSITION_MAX) {
            pa_dbus_send_error(conn, msg, DBUS_ERROR_INVALID_ARGS, "Invalid channel position: %u", chan_pos);
            return -1;
        }

        pa_assert_se(dbus_message_iter_next(&struct_iter));
        dbus_message_iter_get_basic(&struct_iter, &chan_vol);

        if (!PA_VOLUME_IS_VALID(chan_vol)) {
            pa_dbus_send_error(conn, msg, DBUS_ERROR_INVALID_ARGS, "Invalid volume: %u", chan_vol);
            return -1;
        }

        if (map->channels < PA_CHANNELS_MAX) {
            map->map[map->channels] = chan_pos;
            vol->values[map->channels] = chan_vol;
        }
        ++map->channels;
        ++vol->channels;

        dbus_message_iter_next(&array_iter);
    }

    if (map->channels > PA_CHANNELS_MAX) {
        pa_dbus_send_error(conn, msg, DBUS_ERROR_INVALID_ARGS, "Too many channels: %u. The maximum is %u.", map->channels, PA_CHANNELS_MAX);
        return -1;
    }

    dbus_message_iter_next(iter);

    return 0;
}

static void append_volume(DBusMessageIter *iter, struct entry *e) {
    DBusMessageIter array_iter;
    DBusMessageIter struct_iter;
    unsigned i;

    pa_assert(iter);
    pa_assert(e);

    pa_assert_se(dbus_message_iter_open_container(iter, DBUS_TYPE_ARRAY, "(uu)", &array_iter));

    if (!e->volume_valid) {
        pa_assert_se(dbus_message_iter_close_container(iter, &array_iter));
        return;
    }

    for (i = 0; i < e->channel_map.channels; ++i) {
        pa_assert_se(dbus_message_iter_open_container(&array_iter, DBUS_TYPE_STRUCT, NULL, &struct_iter));

        pa_assert_se(dbus_message_iter_append_basic(&struct_iter, DBUS_TYPE_UINT32, &e->channel_map.map[i]));
        pa_assert_se(dbus_message_iter_append_basic(&struct_iter, DBUS_TYPE_UINT32, &e->volume.values[i]));

        pa_assert_se(dbus_message_iter_close_container(&array_iter, &struct_iter));
    }

    pa_assert_se(dbus_message_iter_close_container(iter, &array_iter));
}

static void append_volume_variant(DBusMessageIter *iter, struct entry *e) {
    DBusMessageIter variant_iter;

    pa_assert(iter);
    pa_assert(e);

    pa_assert_se(dbus_message_iter_open_container(iter, DBUS_TYPE_VARIANT, "a(uu)", &variant_iter));

    append_volume(&variant_iter, e);

    pa_assert_se(dbus_message_iter_close_container(iter, &variant_iter));
}

static void send_new_entry_signal(struct dbus_entry *entry) {
    DBusMessage *signal_msg;

    pa_assert(entry);

    pa_assert_se(signal_msg = dbus_message_new_signal(OBJECT_PATH, INTERFACE_STREAM_RESTORE, signals[SIGNAL_NEW_ENTRY].name));
    pa_assert_se(dbus_message_append_args(signal_msg, DBUS_TYPE_OBJECT_PATH, &entry->object_path, DBUS_TYPE_INVALID));
    pa_dbus_protocol_send_signal(entry->userdata->dbus_protocol, signal_msg);
    dbus_message_unref(signal_msg);
}

static void send_entry_removed_signal(struct dbus_entry *entry) {
    DBusMessage *signal_msg;

    pa_assert(entry);

    pa_assert_se(signal_msg = dbus_message_new_signal(OBJECT_PATH, INTERFACE_STREAM_RESTORE, signals[SIGNAL_ENTRY_REMOVED].name));
    pa_assert_se(dbus_message_append_args(signal_msg, DBUS_TYPE_OBJECT_PATH, &entry->object_path, DBUS_TYPE_INVALID));
    pa_dbus_protocol_send_signal(entry->userdata->dbus_protocol, signal_msg);
    dbus_message_unref(signal_msg);
}

static void send_device_updated_signal(struct dbus_entry *de, struct entry *e) {
    DBusMessage *signal_msg;
    const char *device;

    pa_assert(de);
    pa_assert(e);

    device = e->device_valid ? e->device : "";

    pa_assert_se(signal_msg = dbus_message_new_signal(de->object_path, INTERFACE_ENTRY, entry_signals[ENTRY_SIGNAL_DEVICE_UPDATED].name));
    pa_assert_se(dbus_message_append_args(signal_msg, DBUS_TYPE_STRING, &device, DBUS_TYPE_INVALID));
    pa_dbus_protocol_send_signal(de->userdata->dbus_protocol, signal_msg);
    dbus_message_unref(signal_msg);
}

static void send_volume_updated_signal(struct dbus_entry *de, struct entry *e) {
    DBusMessage *signal_msg;
    DBusMessageIter msg_iter;

    pa_assert(de);
    pa_assert(e);

    pa_assert_se(signal_msg = dbus_message_new_signal(de->object_path, INTERFACE_ENTRY, entry_signals[ENTRY_SIGNAL_VOLUME_UPDATED].name));
    dbus_message_iter_init_append(signal_msg, &msg_iter);
    append_volume(&msg_iter, e);
    pa_dbus_protocol_send_signal(de->userdata->dbus_protocol, signal_msg);
    dbus_message_unref(signal_msg);
}

static void send_mute_updated_signal(struct dbus_entry *de, struct entry *e) {
    DBusMessage *signal_msg;
    dbus_bool_t muted;

    pa_assert(de);
    pa_assert(e);

    pa_assert(e->muted_valid);

    muted = e->muted;

    pa_assert_se(signal_msg = dbus_message_new_signal(de->object_path, INTERFACE_ENTRY, entry_signals[ENTRY_SIGNAL_MUTE_UPDATED].name));
    pa_assert_se(dbus_message_append_args(signal_msg, DBUS_TYPE_BOOLEAN, &muted, DBUS_TYPE_INVALID));
    pa_dbus_protocol_send_signal(de->userdata->dbus_protocol, signal_msg);
    dbus_message_unref(signal_msg);
}

static void handle_get_interface_revision(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    dbus_uint32_t interface_revision = DBUS_INTERFACE_REVISION;

    pa_assert(conn);
    pa_assert(msg);

    pa_dbus_send_basic_variant_reply(conn, msg, DBUS_TYPE_UINT32, &interface_revision);
}

/* The caller frees the array, but not the strings. */
static const char **get_entries(struct userdata *u, unsigned *n) {
    const char **entries;
    unsigned i = 0;
    void *state = NULL;
    struct dbus_entry *de;

    pa_assert(u);
    pa_assert(n);

    *n = pa_hashmap_size(u->dbus_entries);

    if (*n == 0)
        return NULL;

    entries = pa_xnew(const char *, *n);

    PA_HASHMAP_FOREACH(de, u->dbus_entries, state)
        entries[i++] = de->object_path;

    return entries;
}

static void handle_get_entries(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct userdata *u = userdata;
    const char **entries;
    unsigned n;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(u);

    entries = get_entries(u, &n);

    pa_dbus_send_basic_array_variant_reply(conn, msg, DBUS_TYPE_OBJECT_PATH, entries, n);

    pa_xfree(entries);
}

static void handle_get_all(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct userdata *u = userdata;
    DBusMessage *reply = NULL;
    DBusMessageIter msg_iter;
    DBusMessageIter dict_iter;
    dbus_uint32_t interface_revision;
    const char **entries;
    unsigned n_entries;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(u);

    interface_revision = DBUS_INTERFACE_REVISION;
    entries = get_entries(u, &n_entries);

    pa_assert_se((reply = dbus_message_new_method_return(msg)));

    dbus_message_iter_init_append(reply, &msg_iter);
    pa_assert_se(dbus_message_iter_open_container(&msg_iter, DBUS_TYPE_ARRAY, "{sv}", &dict_iter));

    pa_dbus_append_basic_variant_dict_entry(&dict_iter, property_handlers[PROPERTY_HANDLER_INTERFACE_REVISION].property_name, DBUS_TYPE_UINT32, &interface_revision);
    pa_dbus_append_basic_array_variant_dict_entry(&dict_iter, property_handlers[PROPERTY_HANDLER_ENTRIES].property_name, DBUS_TYPE_OBJECT_PATH, entries, n_entries);

    pa_assert_se(dbus_message_iter_close_container(&msg_iter, &dict_iter));

    pa_assert_se(dbus_connection_send(conn, reply, NULL));

    dbus_message_unref(reply);

    pa_xfree(entries);
}

static void handle_add_entry(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct userdata *u = userdata;
    DBusMessageIter msg_iter;
    const char *name = NULL;
    const char *device = NULL;
    pa_channel_map map;
    pa_cvolume vol;
    dbus_bool_t muted = FALSE;
    dbus_bool_t apply_immediately = FALSE;
    struct dbus_entry *dbus_entry = NULL;
    struct entry *e = NULL;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(u);

    pa_assert_se(dbus_message_iter_init(msg, &msg_iter));
    dbus_message_iter_get_basic(&msg_iter, &name);

    pa_assert_se(dbus_message_iter_next(&msg_iter));
    dbus_message_iter_get_basic(&msg_iter, &device);

    pa_assert_se(dbus_message_iter_next(&msg_iter));
    if (get_volume_arg(conn, msg, &msg_iter, &map, &vol) < 0)
        return;

    dbus_message_iter_get_basic(&msg_iter, &muted);

    pa_assert_se(dbus_message_iter_next(&msg_iter));
    dbus_message_iter_get_basic(&msg_iter, &apply_immediately);

    if (!*name) {
        pa_dbus_send_error(conn, msg, DBUS_ERROR_INVALID_ARGS, "An empty string was given as the entry name.");
        return;
    }

    if ((dbus_entry = pa_hashmap_get(u->dbus_entries, name))) {
        bool mute_updated = false;
        bool volume_updated = false;
        bool device_updated = false;

        pa_assert_se(e = entry_read(u, name));
        mute_updated = e->muted != muted;
        e->muted = muted;
        e->muted_valid = true;

        volume_updated = (e->volume_valid != !!map.channels) || !pa_cvolume_equal(&e->volume, &vol);
        e->volume = vol;
        e->channel_map = map;
        e->volume_valid = !!map.channels;

        device_updated = (e->device_valid != !!device[0]) || !pa_safe_streq(e->device, device);
        pa_xfree(e->device);
        e->device = pa_xstrdup(device);
        e->device_valid = !!device[0];

        if (mute_updated)
            send_mute_updated_signal(dbus_entry, e);
        if (volume_updated)
            send_volume_updated_signal(dbus_entry, e);
        if (device_updated)
            send_device_updated_signal(dbus_entry, e);

    } else {
        dbus_entry = dbus_entry_new(u, name);
        pa_assert_se(pa_hashmap_put(u->dbus_entries, dbus_entry->entry_name, dbus_entry) == 0);

        e = entry_new();
        e->muted_valid = true;
        e->volume_valid = !!map.channels;
        e->device_valid = !!device[0];
        e->muted = muted;
        e->volume = vol;
        e->channel_map = map;
        e->device = pa_xstrdup(device);

        send_new_entry_signal(dbus_entry);
    }

    pa_assert_se(entry_write(u, name, e, true));

    if (apply_immediately)
        entry_apply(u, name, e);

    trigger_save(u);

    pa_dbus_send_empty_reply(conn, msg);

    entry_free(e);
}

static void handle_get_entry_by_name(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct userdata *u = userdata;
    const char *name;
    struct dbus_entry *de;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(u);

    pa_assert_se(dbus_message_get_args(msg, NULL, DBUS_TYPE_STRING, &name, DBUS_TYPE_INVALID));

    if (!(de = pa_hashmap_get(u->dbus_entries, name))) {
        pa_dbus_send_error(conn, msg, PA_DBUS_ERROR_NOT_FOUND, "No such stream restore entry.");
        return;
    }

    pa_dbus_send_basic_value_reply(conn, msg, DBUS_TYPE_OBJECT_PATH, &de->object_path);
}

static void handle_entry_get_index(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    pa_dbus_send_basic_variant_reply(conn, msg, DBUS_TYPE_UINT32, &de->index);
}

static void handle_entry_get_name(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    pa_dbus_send_basic_variant_reply(conn, msg, DBUS_TYPE_STRING, &de->entry_name);
}

static void handle_entry_get_device(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;
    struct entry *e;
    const char *device;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    device = e->device_valid ? e->device : "";

    pa_dbus_send_basic_variant_reply(conn, msg, DBUS_TYPE_STRING, &device);

    entry_free(e);
}

static void handle_entry_set_device(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, void *userdata) {
    struct dbus_entry *de = userdata;
    const char *device;
    struct entry *e;
    bool updated;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(iter);
    pa_assert(de);

    dbus_message_iter_get_basic(iter, &device);

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    updated = (e->device_valid != !!device[0]) || !pa_safe_streq(e->device, device);

    if (updated) {
        pa_xfree(e->device);
        e->device = pa_xstrdup(device);
        e->device_valid = !!device[0];

        pa_assert_se(entry_write(de->userdata, de->entry_name, e, true));

        entry_apply(de->userdata, de->entry_name, e);
        send_device_updated_signal(de, e);
        trigger_save(de->userdata);
    }

    pa_dbus_send_empty_reply(conn, msg);

    entry_free(e);
}

static void handle_entry_get_volume(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;
    DBusMessage *reply;
    DBusMessageIter msg_iter;
    struct entry *e;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    pa_assert_se(reply = dbus_message_new_method_return(msg));

    dbus_message_iter_init_append(reply, &msg_iter);
    append_volume_variant(&msg_iter, e);

    pa_assert_se(dbus_connection_send(conn, reply, NULL));

    entry_free(e);
}

static void handle_entry_set_volume(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, void *userdata) {
    struct dbus_entry *de = userdata;
    pa_channel_map map;
    pa_cvolume vol;
    struct entry *e = NULL;
    bool updated = false;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(iter);
    pa_assert(de);

    if (get_volume_arg(conn, msg, iter, &map, &vol) < 0)
        return;

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    updated = (e->volume_valid != !!map.channels) || !pa_cvolume_equal(&e->volume, &vol);

    if (updated) {
        e->volume = vol;
        e->channel_map = map;
        e->volume_valid = !!map.channels;

        pa_assert_se(entry_write(de->userdata, de->entry_name, e, true));

        entry_apply(de->userdata, de->entry_name, e);
        send_volume_updated_signal(de, e);
        trigger_save(de->userdata);
    }

    pa_dbus_send_empty_reply(conn, msg);

    entry_free(e);
}

static void handle_entry_get_mute(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;
    struct entry *e;
    dbus_bool_t mute;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    mute = e->muted_valid ? e->muted : FALSE;

    pa_dbus_send_basic_variant_reply(conn, msg, DBUS_TYPE_BOOLEAN, &mute);

    entry_free(e);
}

static void handle_entry_set_mute(DBusConnection *conn, DBusMessage *msg, DBusMessageIter *iter, void *userdata) {
    struct dbus_entry *de = userdata;
    dbus_bool_t mute;
    struct entry *e;
    bool updated;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(iter);
    pa_assert(de);

    dbus_message_iter_get_basic(iter, &mute);

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    updated = !e->muted_valid || e->muted != mute;

    if (updated) {
        e->muted = mute;
        e->muted_valid = true;

        pa_assert_se(entry_write(de->userdata, de->entry_name, e, true));

        entry_apply(de->userdata, de->entry_name, e);
        send_mute_updated_signal(de, e);
        trigger_save(de->userdata);
    }

    pa_dbus_send_empty_reply(conn, msg);

    entry_free(e);
}

static void handle_entry_get_all(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;
    struct entry *e;
    DBusMessage *reply = NULL;
    DBusMessageIter msg_iter;
    DBusMessageIter dict_iter;
    DBusMessageIter dict_entry_iter;
    const char *device;
    dbus_bool_t mute;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    pa_assert_se(e = entry_read(de->userdata, de->entry_name));

    device = e->device_valid ? e->device : "";
    mute = e->muted_valid ? e->muted : FALSE;

    pa_assert_se((reply = dbus_message_new_method_return(msg)));

    dbus_message_iter_init_append(reply, &msg_iter);
    pa_assert_se(dbus_message_iter_open_container(&msg_iter, DBUS_TYPE_ARRAY, "{sv}", &dict_iter));

    pa_dbus_append_basic_variant_dict_entry(&dict_iter, entry_property_handlers[ENTRY_PROPERTY_HANDLER_INDEX].property_name, DBUS_TYPE_UINT32, &de->index);
    pa_dbus_append_basic_variant_dict_entry(&dict_iter, entry_property_handlers[ENTRY_PROPERTY_HANDLER_NAME].property_name, DBUS_TYPE_STRING, &de->entry_name);
    pa_dbus_append_basic_variant_dict_entry(&dict_iter, entry_property_handlers[ENTRY_PROPERTY_HANDLER_DEVICE].property_name, DBUS_TYPE_STRING, &device);

    pa_assert_se(dbus_message_iter_open_container(&dict_iter, DBUS_TYPE_DICT_ENTRY, NULL, &dict_entry_iter));

    pa_assert_se(dbus_message_iter_append_basic(&dict_entry_iter, DBUS_TYPE_STRING, &entry_property_handlers[ENTRY_PROPERTY_HANDLER_VOLUME].property_name));
    append_volume_variant(&dict_entry_iter, e);

    pa_assert_se(dbus_message_iter_close_container(&dict_iter, &dict_entry_iter));

    pa_dbus_append_basic_variant_dict_entry(&dict_iter, entry_property_handlers[ENTRY_PROPERTY_HANDLER_MUTE].property_name, DBUS_TYPE_BOOLEAN, &mute);

    pa_assert_se(dbus_message_iter_close_container(&msg_iter, &dict_iter));

    pa_assert_se(dbus_connection_send(conn, reply, NULL));

    dbus_message_unref(reply);

    entry_free(e);
}

static void handle_entry_remove(DBusConnection *conn, DBusMessage *msg, void *userdata) {
    struct dbus_entry *de = userdata;
    pa_datum key;

    pa_assert(conn);
    pa_assert(msg);
    pa_assert(de);

    key.data = de->entry_name;
    key.size = strlen(de->entry_name);

    pa_assert_se(pa_database_unset(de->userdata->database, &key) == 0);

    send_entry_removed_signal(de);
    trigger_save(de->userdata);

    pa_assert_se(pa_hashmap_remove_and_free(de->userdata->dbus_entries, de->entry_name) >= 0);

    pa_dbus_send_empty_reply(conn, msg);
}

#endif /* HAVE_DBUS */

static void save_time_callback(pa_mainloop_api*a, pa_time_event* e, const struct timeval *t, void *userdata) {
    struct userdata *u = userdata;

    pa_assert(a);
    pa_assert(e);
    pa_assert(u);

    pa_assert(e == u->save_time_event);
    u->core->mainloop->time_free(u->save_time_event);
    u->save_time_event = NULL;

    pa_database_sync(u->database);
    pa_log_info("Synced.");
}

static struct entry* entry_new(void) {
    struct entry *r = pa_xnew0(struct entry, 1);
    return r;
}

static void entry_free(struct entry* e) {
    pa_assert(e);

    pa_xfree(e->device);
    pa_xfree(e->card);
    pa_xfree(e);
}

static bool entry_write(struct userdata *u, const char *name, const struct entry *e, bool replace) {
    pa_tagstruct *t;
    pa_datum key, data;
    bool r;

    pa_assert(u);
    pa_assert(name);
    pa_assert(e);

    t = pa_tagstruct_new();
    pa_tagstruct_putu8(t, ENTRY_VERSION);
    pa_tagstruct_put_boolean(t, e->volume_valid);
    pa_tagstruct_put_channel_map(t, &e->channel_map);
    pa_tagstruct_put_cvolume(t, &e->volume);
    pa_tagstruct_put_boolean(t, e->muted_valid);
    pa_tagstruct_put_boolean(t, e->muted);
    pa_tagstruct_put_boolean(t, e->device_valid);
    pa_tagstruct_puts(t, e->device);
    pa_tagstruct_put_boolean(t, e->card_valid);
    pa_tagstruct_puts(t, e->card);

    key.data = (char *) name;
    key.size = strlen(name);

    data.data = (void*)pa_tagstruct_data(t, &data.size);

    r = (pa_database_set(u->database, &key, &data, replace) == 0);

    pa_tagstruct_free(t);

    return r;
}

#ifdef ENABLE_LEGACY_DATABASE_ENTRY_FORMAT

#define LEGACY_ENTRY_VERSION 3
static struct entry *legacy_entry_read(struct userdata *u, const char *name) {
    struct legacy_entry {
        uint8_t version;
        bool muted_valid:1, volume_valid:1, device_valid:1, card_valid:1;
        bool muted:1;
        pa_channel_map channel_map;
        pa_cvolume volume;
        char device[PA_NAME_MAX];
        char card[PA_NAME_MAX];
    } PA_GCC_PACKED;

    pa_datum key;
    pa_datum data;
    struct legacy_entry *le;
    struct entry *e;

    pa_assert(u);
    pa_assert(name);

    key.data = (char *) name;
    key.size = strlen(name);

    pa_zero(data);

    if (!pa_database_get(u->database, &key, &data))
        goto fail;

    if (data.size != sizeof(struct legacy_entry)) {
        pa_log_debug("Size does not match.");
        goto fail;
    }

    le = (struct legacy_entry *) data.data;

    if (le->version != LEGACY_ENTRY_VERSION) {
        pa_log_debug("Version mismatch.");
        goto fail;
    }

    if (!memchr(le->device, 0, sizeof(le->device))) {
        pa_log_warn("Device has missing NUL byte.");
        goto fail;
    }

    if (!memchr(le->card, 0, sizeof(le->card))) {
        pa_log_warn("Card has missing NUL byte.");
        goto fail;
    }

    if (le->device_valid && !pa_namereg_is_valid_name(le->device)) {
        pa_log_warn("Invalid device name stored in database for legacy stream");
        goto fail;
    }

    if (le->card_valid && !pa_namereg_is_valid_name(le->card)) {
        pa_log_warn("Invalid card name stored in database for legacy stream");
        goto fail;
    }

    if (le->volume_valid && !pa_channel_map_valid(&le->channel_map)) {
        pa_log_warn("Invalid channel map stored in database for legacy stream");
        goto fail;
    }

    if (le->volume_valid && (!pa_cvolume_valid(&le->volume) || !pa_cvolume_compatible_with_channel_map(&le->volume, &le->channel_map))) {
        pa_log_warn("Invalid volume stored in database for legacy stream");
        goto fail;
    }

    e = entry_new();
    e->muted_valid = le->muted_valid;
    e->muted = le->muted;
    e->volume_valid = le->volume_valid;
    e->channel_map = le->channel_map;
    e->volume = le->volume;
    e->device_valid = le->device_valid;
    e->device = pa_xstrdup(le->device);
    e->card_valid = le->card_valid;
    e->card = pa_xstrdup(le->card);
    return e;

fail:
    pa_datum_free(&data);

    return NULL;
}
#endif

static struct entry *entry_read(struct userdata *u, const char *name) {
    pa_datum key, data;
    struct entry *e = NULL;
    pa_tagstruct *t = NULL;
    uint8_t version;
    const char *device, *card;

    pa_assert(u);
    pa_assert(name);

    key.data = (char*) name;
    key.size = strlen(name);

    pa_zero(data);

    if (!pa_database_get(u->database, &key, &data))
        goto fail;

    t = pa_tagstruct_new_fixed(data.data, data.size);
    e = entry_new();

    if (pa_tagstruct_getu8(t, &version) < 0 ||
        version > ENTRY_VERSION ||
        pa_tagstruct_get_boolean(t, &e->volume_valid) < 0 ||
        pa_tagstruct_get_channel_map(t, &e->channel_map) < 0 ||
        pa_tagstruct_get_cvolume(t, &e->volume) < 0 ||
        pa_tagstruct_get_boolean(t, &e->muted_valid) < 0 ||
        pa_tagstruct_get_boolean(t, &e->muted) < 0 ||
        pa_tagstruct_get_boolean(t, &e->device_valid) < 0 ||
        pa_tagstruct_gets(t, &device) < 0 ||
        pa_tagstruct_get_boolean(t, &e->card_valid) < 0 ||
        pa_tagstruct_gets(t, &card) < 0) {

        goto fail;
    }

    e->device = pa_xstrdup(device);
    e->card = pa_xstrdup(card);

    if (!pa_tagstruct_eof(t))
        goto fail;

    if (e->device_valid && (!e->device || !pa_namereg_is_valid_name(e->device))) {
        pa_log_warn("Invalid device name stored in database for stream %s", name);
        goto fail;
    }

    if (e->card_valid && (!e->card || !pa_namereg_is_valid_name(e->card))) {
        pa_log_warn("Invalid card name stored in database for stream %s", name);
        goto fail;
    }

    if (e->volume_valid && !pa_channel_map_valid(&e->channel_map)) {
        pa_log_warn("Invalid channel map stored in database for stream %s", name);
        goto fail;
    }

    if (e->volume_valid && (!pa_cvolume_valid(&e->volume) || !pa_cvolume_compatible_with_channel_map(&e->volume, &e->channel_map))) {
        pa_log_warn("Invalid volume stored in database for stream %s", name);
        goto fail;
    }

    pa_tagstruct_free(t);
    pa_datum_free(&data);

#ifdef STREAM_RESTORE_CLEAR_OLD_DEVICES
    if (version < ENTRY_VERSION && e->device_valid) {
        /* Prior to PulseAudio 14.0, GNOME's sound settings overwrote the
         * routing for all entries in the stream-restore database when
         * selecting a device. PulseAudio 14.0 prevents that from happening,
         * but the old overwritten settings can still be in the database after
         * updating to PulseAudio 14.0, and they can cause problems, as
         * documented here:
         * https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/832
         *
         * We can't distinguish between devices set by GNOME's sound settings
         * and devices set by the user, so we discard all old device settings,
         * even though that is going to cause PulseAudio to forget routing
         * settings for many users. This is less bad than keeping the incorrect
         * routing settings in the database, because it's difficult for users
         * to figure out how to fix the situation when e.g. speaker test tones
         * go to the internal speakers no matter what device is selected as the
         * default, whereas old manual configuration can be restored restored
         * by doing the manual configuration again. Also, it's probably more
         * common to have at some point changed the default device in GNOME's
         * sound settings than it is to have any manual per-stream routing
         * settings. */
        pa_log_warn("Device set, but it might be incorrect. Clearing the device. If this messes up your manual stream "
                    "routing configuration, sorry about that. This is a workaround for this bug: "
                    "https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/832");
        pa_log_warn("%s: device: %s -> (unset)", name, e->device);
        pa_xfree(e->device);
        e->device = NULL;
        e->device_valid = false;
        if (e->card_valid) {
            pa_log_warn("%s: card: %s -> (unset)", name, e->card);
            pa_xfree(e->card);
            e->card = NULL;
            e->card_valid = false;
        }
        entry_write(u, name, e, true);
        trigger_save(u);
    }
#endif

    return e;

fail:
    if (e)
        entry_free(e);
    if (t)
        pa_tagstruct_free(t);

    pa_datum_free(&data);
    return NULL;
}

static struct entry* entry_copy(const struct entry *e) {
    struct entry* r;

    pa_assert(e);
    r = entry_new();
    *r = *e;
    r->device = pa_xstrdup(e->device);
    r->card = pa_xstrdup(e->card);
    return r;
}

static void trigger_save(struct userdata *u) {
    pa_native_connection *c;
    uint32_t idx;

    PA_IDXSET_FOREACH(c, u->subscribed, idx) {
        pa_tagstruct *t;

        t = pa_tagstruct_new();
        pa_tagstruct_putu32(t, PA_COMMAND_EXTENSION);
        pa_tagstruct_putu32(t, 0);
        pa_tagstruct_putu32(t, u->module->index);
        pa_tagstruct_puts(t, u->module->name);
        pa_tagstruct_putu32(t, SUBCOMMAND_EVENT);

        pa_pstream_send_tagstruct(pa_native_connection_get_pstream(c), t);
    }

    if (u->save_time_event)
        return;

    u->save_time_event = pa_core_rttime_new(u->core, pa_rtclock_now() + SAVE_INTERVAL, save_time_callback, u);
}

static bool entries_equal(const struct entry *a, const struct entry *b) {
    pa_cvolume t;

    pa_assert(a);
    pa_assert(b);

    if (a->device_valid != b->device_valid ||
        (a->device_valid && !pa_streq(a->device, b->device)))
        return false;

    if (a->card_valid != b->card_valid ||
        (a->card_valid && !pa_streq(a->card, b->card)))
        return false;

    if (a->muted_valid != b->muted_valid ||
        (a->muted_valid && (a->muted != b->muted)))
        return false;

    t = b->volume;
    if (a->volume_valid != b->volume_valid ||
        (a->volume_valid && !pa_cvolume_equal(pa_cvolume_remap(&t, &b->channel_map, &a->channel_map), &a->volume)))
        return false;

    return true;
}

static void subscribe_callback(pa_core *c, pa_subscription_event_type_t t, uint32_t idx, void *userdata) {
    struct userdata *u = userdata;
    struct entry *entry, *old = NULL;
    char *name = NULL;

    /* These are only used when D-Bus is enabled, but in order to reduce ifdef
     * clutter these are defined here unconditionally. */
    bool created_new_entry = true;
    bool device_updated = false;
    bool volume_updated = false;
    bool mute_updated = false;

#ifdef HAVE_DBUS
    struct dbus_entry *de = NULL;
#endif

    pa_assert(c);
    pa_assert(u);

    if (t != (PA_SUBSCRIPTION_EVENT_SINK_INPUT|PA_SUBSCRIPTION_EVENT_NEW) &&
        t != (PA_SUBSCRIPTION_EVENT_SINK_INPUT|PA_SUBSCRIPTION_EVENT_CHANGE) &&
        t != (PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT|PA_SUBSCRIPTION_EVENT_NEW) &&
        t != (PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT|PA_SUBSCRIPTION_EVENT_CHANGE))
        return;

    if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) == PA_SUBSCRIPTION_EVENT_SINK_INPUT) {
        pa_sink_input *sink_input;

        if (!(sink_input = pa_idxset_get_by_index(c->sink_inputs, idx)))
            return;

        /* Ignore this sink input if it is connecting a filter sink to
         * the master */
        if (sink_input->origin_sink)
            return;

        if (!(name = pa_proplist_get_stream_group(sink_input->proplist, "sink-input", IDENTIFICATION_PROPERTY)))
            return;

        if ((old = entry_read(u, name))) {
            entry = entry_copy(old);
            created_new_entry = false;
        } else
            entry = entry_new();

        if (sink_input->save_volume && pa_sink_input_is_volume_readable(sink_input)) {
            pa_assert(sink_input->volume_writable);

            entry->channel_map = sink_input->channel_map;
            pa_sink_input_get_volume(sink_input, &entry->volume, false);
            entry->volume_valid = true;

            volume_updated = !created_new_entry
                             && (!old->volume_valid
                                 || !pa_channel_map_equal(&entry->channel_map, &old->channel_map)
                                 || !pa_cvolume_equal(&entry->volume, &old->volume));
        }

        if (sink_input->save_muted) {
            entry->muted = sink_input->muted;
            entry->muted_valid = true;

            mute_updated = !created_new_entry && (!old->muted_valid || entry->muted != old->muted);
        }

        if (sink_input->preferred_sink != NULL || !created_new_entry) {
            pa_sink *s = NULL;

            pa_xfree(entry->device);
            entry->device = pa_xstrdup(sink_input->preferred_sink);
            entry->device_valid = true;
            if (!entry->device)
                entry->device_valid = false;

            device_updated = !created_new_entry && !pa_safe_streq(entry->device, old->device);
            pa_xfree(entry->card);
            entry->card = NULL;
            entry->card_valid = false;
            if (entry->device_valid && (s = pa_namereg_get(c, entry->device, PA_NAMEREG_SINK)) && s->card) {
                entry->card = pa_xstrdup(s->card->name);
                entry->card_valid = true;
            }
        }
    } else {
        pa_source_output *source_output;

        pa_assert((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) == PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT);

        if (!(source_output = pa_idxset_get_by_index(c->source_outputs, idx)))
            return;

        /* Ignore this source output if it is connecting a filter source to
         * the master */
        if (source_output->destination_source)
            return;

        if (!(name = pa_proplist_get_stream_group(source_output->proplist, "source-output", IDENTIFICATION_PROPERTY)))
            return;

        if ((old = entry_read(u, name))) {
            entry = entry_copy(old);
            created_new_entry = false;
        } else
            entry = entry_new();

        if (source_output->save_volume && pa_source_output_is_volume_readable(source_output)) {
            pa_assert(source_output->volume_writable);

            entry->channel_map = source_output->channel_map;
            pa_source_output_get_volume(source_output, &entry->volume, false);
            entry->volume_valid = true;

            volume_updated = !created_new_entry
                             && (!old->volume_valid
                                 || !pa_channel_map_equal(&entry->channel_map, &old->channel_map)
                                 || !pa_cvolume_equal(&entry->volume, &old->volume));
        }

        if (source_output->save_muted) {
            entry->muted = source_output->muted;
            entry->muted_valid = true;

            mute_updated = !created_new_entry && (!old->muted_valid || entry->muted != old->muted);
        }

        if (source_output->preferred_source != NULL || !created_new_entry) {
            pa_source *s = NULL;

            pa_xfree(entry->device);
            entry->device = pa_xstrdup(source_output->preferred_source);
            entry->device_valid = true;

            if (!entry->device)
                entry->device_valid = false;

            device_updated = !created_new_entry && !pa_safe_streq(entry->device, old->device);
            pa_xfree(entry->card);
            entry->card = NULL;
            entry->card_valid = false;
            if (entry->device_valid && (s = pa_namereg_get(c, entry->device, PA_NAMEREG_SOURCE)) && s->card) {
                entry->card = pa_xstrdup(s->card->name);
                entry->card_valid = true;
            }
        }
    }

    pa_assert(entry);

    if (old) {

        if (entries_equal(old, entry)) {
            entry_free(old);
            entry_free(entry);
            pa_xfree(name);
            return;
        }

        entry_free(old);
    }

    pa_log_info("Storing volume/mute/device for stream %s.", name);

    if (entry_write(u, name, entry, true)) {
        trigger_save(u);
    } else {
        pa_log_error("Could not store volume/mute/device for stream %s.", name);
    }

#ifdef HAVE_DBUS
    if (!(de = pa_hashmap_get(u->dbus_entries, name))) {
        de = dbus_entry_new(u, name);
        pa_assert_se(pa_hashmap_put(u->dbus_entries, de->entry_name, de) == 0);
        send_new_entry_signal(de);
    } else {
        if (device_updated)
            send_device_updated_signal(de, entry);
        if (volume_updated)
            send_volume_updated_signal(de, entry);
        if (mute_updated)
            send_mute_updated_signal(de, entry);
    }
#else
    /* Silence compiler warnings */
    (void) device_updated;
    (void) volume_updated;
    (void) mute_updated;
#endif

    entry_free(entry);
    pa_xfree(name);
}

static pa_hook_result_t sink_input_new_hook_callback(pa_core *c, pa_sink_input_new_data *new_data, struct userdata *u) {
    char *name;
    struct entry *e;

    pa_assert(c);
    pa_assert(new_data);
    pa_assert(u);
    pa_assert(u->restore_device);

    if (!(name = pa_proplist_get_stream_group(new_data->proplist, "sink-input", IDENTIFICATION_PROPERTY)))
        return PA_HOOK_OK;

    if (new_data->sink)
        pa_log_debug("Not restoring device for stream %s, because already set to '%s'.", name, new_data->sink->name);
    else if (new_data->origin_sink)
        pa_log_debug("Not restoring device for stream %s, because it connects a filter to the master sink.", name);
    else if ((e = entry_read(u, name))) {
        pa_sink *s = NULL;

        if (e->device_valid) {
            s = pa_namereg_get(c, e->device, PA_NAMEREG_SINK);
            new_data->preferred_sink = pa_xstrdup(e->device);
        }

        if (!s && e->card_valid) {
            pa_card *card;

            if ((card = pa_namereg_get(c, e->card, PA_NAMEREG_CARD)))
                s = pa_idxset_first(card->sinks, NULL);
        }

        /* It might happen that a stream and a sink are set up at the
           same time, in which case we want to make sure we don't
           interfere with that */
        if (s && PA_SINK_IS_LINKED(s->state))
            if (!s->active_port || s->active_port->available != PA_AVAILABLE_NO) {
                if (pa_sink_input_new_data_set_sink(new_data, s, true, false))
                    pa_log_info("Restoring device for stream %s.", name);
	    }

        entry_free(e);
    }

    pa_xfree(name);

    return PA_HOOK_OK;
}

static pa_hook_result_t sink_input_fixate_hook_callback(pa_core *c, pa_sink_input_new_data *new_data, struct userdata *u) {
    char *name;
    struct entry *e;

    pa_assert(c);
    pa_assert(new_data);
    pa_assert(u);
    pa_assert(u->restore_volume || u->restore_muted);

    if (!(name = pa_proplist_get_stream_group(new_data->proplist, "sink-input", IDENTIFICATION_PROPERTY)))
        return PA_HOOK_OK;

    if (new_data->origin_sink) {
        pa_log_debug("Not restoring volume for sink input %s, because it connects a filter to the master sink.", name);
        return PA_HOOK_OK;
    }

    if ((e = entry_read(u, name))) {

        if (u->restore_volume && e->volume_valid) {
            if (!new_data->volume_writable)
                pa_log_debug("Not restoring volume for sink input %s, because its volume can't be changed.", name);
            else if (new_data->volume_is_set)
                pa_log_debug("Not restoring volume for sink input %s, because already set.", name);
            else {
                pa_cvolume v;

                pa_log_info("Restoring volume for sink input %s.", name);

                v = e->volume;
                pa_cvolume_remap(&v, &e->channel_map, &new_data->channel_map);
                pa_sink_input_new_data_set_volume(new_data, &v);

                new_data->volume_is_absolute = false;
                new_data->save_volume = true;
            }
        }

        if (u->restore_muted && e->muted_valid) {

            if (!new_data->muted_is_set) {
                pa_log_info("Restoring mute state for sink input %s.", name);
                pa_sink_input_new_data_set_muted(new_data, e->muted);
                new_data->save_muted = true;
            } else
                pa_log_debug("Not restoring mute state for sink input %s, because already set.", name);
        }

        entry_free(e);
    }

    pa_xfree(name);

    return PA_HOOK_OK;
}

static pa_hook_result_t source_output_new_hook_callback(pa_core *c, pa_source_output_new_data *new_data, struct userdata *u) {
    char *name;
    struct entry *e;

    pa_assert(c);
    pa_assert(new_data);
    pa_assert(u);
    pa_assert(u->restore_device);

    if (new_data->direct_on_input)
        return PA_HOOK_OK;

    if (!(name = pa_proplist_get_stream_group(new_data->proplist, "source-output", IDENTIFICATION_PROPERTY)))
        return PA_HOOK_OK;

    if (new_data->source)
        pa_log_debug("Not restoring device for stream %s, because already set", name);
    else if (new_data->destination_source)
        pa_log_debug("Not restoring device for stream %s, because it connects a filter to the master source.", name);
    else if ((e = entry_read(u, name))) {
        pa_source *s = NULL;

        if (e->device_valid) {
            s = pa_namereg_get(c, e->device, PA_NAMEREG_SOURCE);
            new_data->preferred_source = pa_xstrdup(e->device);
        }

        if (!s && e->card_valid) {
            pa_card *card;

            if ((card = pa_namereg_get(c, e->card, PA_NAMEREG_CARD)))
                s = pa_idxset_first(card->sources, NULL);
        }

        /* It might happen that a stream and a sink are set up at the
           same time, in which case we want to make sure we don't
           interfere with that */
        if (s && PA_SOURCE_IS_LINKED(s->state)) {
            if (!s->active_port || s->active_port->available != PA_AVAILABLE_NO) {
                pa_log_info("Restoring device for stream %s.", name);
                pa_source_output_new_data_set_source(new_data, s, true, false);
	    }
        }

        entry_free(e);
    }

    pa_xfree(name);

    return PA_HOOK_OK;
}

static pa_hook_result_t source_output_fixate_hook_callback(pa_core *c, pa_source_output_new_data *new_data, struct userdata *u) {
    char *name;
    struct entry *e;

    pa_assert(c);
    pa_assert(new_data);
    pa_assert(u);
    pa_assert(u->restore_volume || u->restore_muted);

    if (!(name = pa_proplist_get_stream_group(new_data->proplist, "source-output", IDENTIFICATION_PROPERTY)))
        return PA_HOOK_OK;

    if (new_data->destination_source) {
        pa_log_debug("Not restoring volume for source output %s, because it connects a filter to the master source.", name);
        return PA_HOOK_OK;
    }

    if ((e = entry_read(u, name))) {

        if (u->restore_volume && e->volume_valid) {
            if (!new_data->volume_writable)
                pa_log_debug("Not restoring volume for source output %s, because its volume can't be changed.", name);
            else if (new_data->volume_is_set)
                pa_log_debug("Not restoring volume for source output %s, because already set.", name);
            else {
                pa_cvolume v;

                pa_log_info("Restoring volume for source output %s.", name);

                v = e->volume;
                pa_cvolume_remap(&v, &e->channel_map, &new_data->channel_map);
                pa_source_output_new_data_set_volume(new_data, &v);

                new_data->volume_is_absolute = false;
                new_data->save_volume = true;
            }
        }

        if (u->restore_muted && e->muted_valid) {

            if (!new_data->muted_is_set) {
                pa_log_info("Restoring mute state for source output %s.", name);
                pa_source_output_new_data_set_muted(new_data, e->muted);
                new_data->save_muted = true;
            } else
                pa_log_debug("Not restoring mute state for source output %s, because already set.", name);
        }

        entry_free(e);
    }

    pa_xfree(name);

    return PA_HOOK_OK;
}

static int fill_db(struct userdata *u, const char *filename) {
    FILE *f;
    int n = 0;
    int ret = -1;
    char *fn = NULL;

    pa_assert(u);

    if (filename)
        f = fopen(fn = pa_xstrdup(filename), "r");
    else
        f = pa_open_config_file(DEFAULT_FALLBACK_FILE, DEFAULT_FALLBACK_FILE_USER, NULL, &fn);

    if (!f) {
        if (filename)
            pa_log("Failed to open %s: %s", filename, pa_cstrerror(errno));
        else
            ret = 0;

        goto finish;
    }

    while (!feof(f)) {
        char ln[256];
        char *d, *v;
        double db;

        if (!fgets(ln, sizeof(ln), f))
            break;

        n++;

        pa_strip_nl(ln);

        if (!*ln || ln[0] == '#' || ln[0] == ';')
            continue;

        d = ln+strcspn(ln, WHITESPACE);
        v = d+strspn(d, WHITESPACE);

        if (!*v) {
            pa_log("[%s:%u] failed to parse line - too few words", fn, n);
            goto finish;
        }

        *d = 0;
        if (pa_atod(v, &db) >= 0) {
            if (db <= 0.0) {
                struct entry e;

                pa_zero(e);
                e.volume_valid = true;
                pa_cvolume_set(&e.volume, 1, pa_sw_volume_from_dB(db));
                pa_channel_map_init_mono(&e.channel_map);

                if (entry_write(u, ln, &e, false))
                    pa_log_debug("Setting %s to %0.2f dB.", ln, db);
            } else
                pa_log_warn("[%s:%u] Positive dB values are not allowed, not setting entry %s.", fn, n, ln);
        } else
            pa_log_warn("[%s:%u] Couldn't parse '%s' as a double, not setting entry %s.", fn, n, v, ln);
    }

    trigger_save(u);
    ret = 0;

finish:
    if (f)
        fclose(f);

    pa_xfree(fn);

    return ret;
}

static void entry_apply(struct userdata *u, const char *name, struct entry *e) {
    pa_sink_input *si;
    pa_source_output *so;
    uint32_t idx;

    pa_assert(u);
    pa_assert(name);
    pa_assert(e);

    PA_IDXSET_FOREACH(si, u->core->sink_inputs, idx) {
        char *n;
        pa_sink *s;

        if (!(n = pa_proplist_get_stream_group(si->proplist, "sink-input", IDENTIFICATION_PROPERTY)))
            continue;

        if (!pa_streq(name, n)) {
            pa_xfree(n);
            continue;
        }
        pa_xfree(n);

        if (u->restore_volume && e->volume_valid && si->volume_writable) {
            pa_cvolume v;

            v = e->volume;
            pa_log_info("Restoring volume for sink input %s.", name);
            pa_cvolume_remap(&v, &e->channel_map, &si->channel_map);
            pa_sink_input_set_volume(si, &v, true, false);
        }

        if (u->restore_muted && e->muted_valid) {
            pa_log_info("Restoring mute state for sink input %s.", name);
            pa_sink_input_set_mute(si, e->muted, true);
        }

        if (u->restore_device) {
            if (!e->device_valid) {
                if (si->preferred_sink != NULL) {
                    pa_log_info("Ensuring device is not saved for stream %s.", name);
                    /* If the device is not valid we should make sure the
                       preferred_sink is cleared as the user may have specifically
                       removed the sink element from the rule. */
                    pa_sink_input_set_preferred_sink(si, NULL);
                }
            } else if ((s = pa_namereg_get(u->core, e->device, PA_NAMEREG_SINK))) {
                pa_log_info("Restoring device for stream %s.", name);
                pa_sink_input_set_preferred_sink(si, s);
            }
        }
    }

    PA_IDXSET_FOREACH(so, u->core->source_outputs, idx) {
        char *n;
        pa_source *s;

        if (!(n = pa_proplist_get_stream_group(so->proplist, "source-output", IDENTIFICATION_PROPERTY)))
            continue;

        if (!pa_streq(name, n)) {
            pa_xfree(n);
            continue;
        }
        pa_xfree(n);

        if (u->restore_volume && e->volume_valid && so->volume_writable) {
            pa_cvolume v;

            v = e->volume;
            pa_log_info("Restoring volume for source output %s.", name);
            pa_cvolume_remap(&v, &e->channel_map, &so->channel_map);
            pa_source_output_set_volume(so, &v, true, false);
        }

        if (u->restore_muted && e->muted_valid) {
            pa_log_info("Restoring mute state for source output %s.", name);
            pa_source_output_set_mute(so, e->muted, true);
        }

        if (u->restore_device) {
            if (!e->device_valid) {
                if (so->preferred_source != NULL) {
                    pa_log_info("Ensuring device is not saved for stream %s.", name);
                    /* If the device is not valid we should make sure the
                       preferred_source is cleared as the user may have specifically
                       removed the source element from the rule. */
                    pa_source_output_set_preferred_source(so, NULL);
                }
            } else if ((s = pa_namereg_get(u->core, e->device, PA_NAMEREG_SOURCE))) {
                pa_log_info("Restoring device for stream %s.", name);
                pa_source_output_set_preferred_source(so, s);
            }
        }
    }
}

#ifdef DEBUG_VOLUME
PA_GCC_UNUSED static void stream_restore_dump_database(struct userdata *u) {
    pa_datum key;
    bool done;

    done = !pa_database_first(u->database, &key, NULL);

    while (!done) {
        pa_datum next_key;
        struct entry *e;
        char *name;

        done = !pa_database_next(u->database, &key, &next_key, NULL);

        name = pa_xstrndup(key.data, key.size);
        pa_datum_free(&key);

        if ((e = entry_read(u, name))) {
            char t[256];
            pa_log("name=%s", name);
            pa_log("device=%s %s", e->device, pa_yes_no(e->device_valid));
            pa_log("channel_map=%s", pa_channel_map_snprint(t, sizeof(t), &e->channel_map));
            pa_log("volume=%s %s",
                   pa_cvolume_snprint_verbose(t, sizeof(t), &e->volume, &e->channel_map, true),
                   pa_yes_no(e->volume_valid));
            pa_log("mute=%s %s", pa_yes_no(e->muted), pa_yes_no(e->volume_valid));
            entry_free(e);
        }

        pa_xfree(name);

        key = next_key;
    }
}
#endif

#define EXT_VERSION 1

static int extension_cb(pa_native_protocol *p, pa_module *m, pa_native_connection *c, uint32_t tag, pa_tagstruct *t) {
    struct userdata *u;
    uint32_t command;
    pa_tagstruct *reply = NULL;

    pa_assert(p);
    pa_assert(m);
    pa_assert(c);
    pa_assert(t);

    u = m->userdata;

    if (pa_tagstruct_getu32(t, &command) < 0)
        goto fail;

    reply = pa_tagstruct_new();
    pa_tagstruct_putu32(reply, PA_COMMAND_REPLY);
    pa_tagstruct_putu32(reply, tag);

    switch (command) {
        case SUBCOMMAND_TEST: {
            if (!pa_tagstruct_eof(t))
                goto fail;

            pa_tagstruct_putu32(reply, EXT_VERSION);
            break;
        }

        case SUBCOMMAND_READ: {
            pa_datum key;
            bool done;

            if (!pa_tagstruct_eof(t))
                goto fail;

            done = !pa_database_first(u->database, &key, NULL);

            while (!done) {
                pa_datum next_key;
                struct entry *e;
                char *name;

                done = !pa_database_next(u->database, &key, &next_key, NULL);

                name = pa_xstrndup(key.data, key.size);
                pa_datum_free(&key);

                if ((e = entry_read(u, name))) {
                    pa_cvolume r;
                    pa_channel_map cm;

                    pa_tagstruct_puts(reply, name);
                    pa_tagstruct_put_channel_map(reply, e->volume_valid ? &e->channel_map : pa_channel_map_init(&cm));
                    pa_tagstruct_put_cvolume(reply, e->volume_valid ? &e->volume : pa_cvolume_init(&r));
                    pa_tagstruct_puts(reply, e->device_valid ? e->device : NULL);
                    pa_tagstruct_put_boolean(reply, e->muted_valid ? e->muted : false);

                    entry_free(e);
                }

                pa_xfree(name);

                key = next_key;
            }

            break;
        }

        case SUBCOMMAND_WRITE: {
            uint32_t mode;
            bool apply_immediately = false;

            if (pa_tagstruct_getu32(t, &mode) < 0 ||
                pa_tagstruct_get_boolean(t, &apply_immediately) < 0)
                goto fail;

            if (mode != PA_UPDATE_MERGE &&
                mode != PA_UPDATE_REPLACE &&
                mode != PA_UPDATE_SET)
                goto fail;

            if (mode == PA_UPDATE_SET) {
#ifdef HAVE_DBUS
                struct dbus_entry *de;
                void *state = NULL;

                PA_HASHMAP_FOREACH(de, u->dbus_entries, state) {
                    send_entry_removed_signal(de);
                    pa_hashmap_remove_and_free(u->dbus_entries, de->entry_name);
                }
#endif
                pa_database_clear(u->database);
            }

            while (!pa_tagstruct_eof(t)) {
                const char *name, *device, *client_name;
                bool muted;
                struct entry *entry;
#ifdef HAVE_DBUS
                struct entry *old;
#endif

                entry = entry_new();

                if (pa_tagstruct_gets(t, &name) < 0 ||
                    pa_tagstruct_get_channel_map(t, &entry->channel_map) ||
                    pa_tagstruct_get_cvolume(t, &entry->volume) < 0 ||
                    pa_tagstruct_gets(t, &device) < 0 ||
                    pa_tagstruct_get_boolean(t, &muted) < 0) {
                    entry_free(entry);
                    goto fail;
                }

                if (!name || !*name) {
                    entry_free(entry);
                    goto fail;
                }

                entry->volume_valid = entry->volume.channels > 0;

                if (entry->volume_valid)
                    if (!pa_cvolume_compatible_with_channel_map(&entry->volume, &entry->channel_map)) {
                        entry_free(entry);
                        goto fail;
                    }

                entry->muted = muted;
                entry->muted_valid = true;

                entry->device = pa_xstrdup(device);
                entry->device_valid = device && !!entry->device[0];

                if (entry->device_valid && !pa_namereg_is_valid_name(entry->device)) {
                    entry_free(entry);
                    goto fail;
                }
                /* When users select an output device from gnome-control-center, the gnome-control-center will change all entries
                 * in the database to bind the sink of this output device, this is not correct since at this moment, the sink is
                 * default_sink and we shouldn't bind a stream to default_sink via preferred_sink or database. This also applies
                 * to source, default_source and preferred_source.
                 * After gnome-control-center fix the issue, let us remove this code */
                client_name = pa_strnull(pa_proplist_gets(pa_native_connection_get_client(c)->proplist, PA_PROP_APPLICATION_PROCESS_BINARY));
                if (pa_safe_streq(client_name, "gnome-control-center")) {
                    if (entry->device_valid && ((m->core->default_sink && pa_safe_streq(device, m->core->default_sink->name)) ||
			(m->core->default_source && pa_safe_streq(device, m->core->default_source->name)))) {
                        entry_free(entry);
                        pa_pstream_send_tagstruct(pa_native_connection_get_pstream(c), reply);
                        return 0;
                    }
                }
#ifdef HAVE_DBUS
                old = entry_read(u, name);
#endif

                pa_log_debug("Client %s changes entry %s.",
                             pa_strnull(pa_proplist_gets(pa_native_connection_get_client(c)->proplist, PA_PROP_APPLICATION_PROCESS_BINARY)),
                             name);

                if (entry_write(u, name, entry, mode == PA_UPDATE_REPLACE)) {
#ifdef HAVE_DBUS
                    struct dbus_entry *de;

                    if (old) {
                        pa_assert_se((de = pa_hashmap_get(u->dbus_entries, name)));

                        if ((old->device_valid != entry->device_valid)
                            || (entry->device_valid && !pa_streq(entry->device, old->device)))
                            send_device_updated_signal(de, entry);

                        if ((old->volume_valid != entry->volume_valid)
                            || (entry->volume_valid && (!pa_cvolume_equal(&entry->volume, &old->volume)
                                                       || !pa_channel_map_equal(&entry->channel_map, &old->channel_map))))
                            send_volume_updated_signal(de, entry);

                        if (!old->muted_valid || (entry->muted != old->muted))
                            send_mute_updated_signal(de, entry);

                    } else {
                        de = dbus_entry_new(u, name);
                        pa_assert_se(pa_hashmap_put(u->dbus_entries, de->entry_name, de) == 0);
                        send_new_entry_signal(de);
                    }
#endif

                    if (apply_immediately)
                        entry_apply(u, name, entry);
                }

#ifdef HAVE_DBUS
                if (old)
                    entry_free(old);
#endif
                entry_free(entry);
            }

            trigger_save(u);

            break;
        }

        case SUBCOMMAND_DELETE:

            while (!pa_tagstruct_eof(t)) {
                const char *name;
                pa_datum key;
#ifdef HAVE_DBUS
                struct dbus_entry *de;
#endif

                if (pa_tagstruct_gets(t, &name) < 0)
                    goto fail;

#ifdef HAVE_DBUS
                if ((de = pa_hashmap_get(u->dbus_entries, name))) {
                    send_entry_removed_signal(de);
                    pa_hashmap_remove_and_free(u->dbus_entries, name);
                }
#endif

                key.data = (char*) name;
                key.size = strlen(name);

                pa_database_unset(u->database, &key);
            }

            trigger_save(u);

            break;

        case SUBCOMMAND_SUBSCRIBE: {

            bool enabled;

            if (pa_tagstruct_get_boolean(t, &enabled) < 0 ||
                !pa_tagstruct_eof(t))
                goto fail;

            if (enabled)
                pa_idxset_put(u->subscribed, c, NULL);
            else
                pa_idxset_remove_by_data(u->subscribed, c, NULL);

            break;
        }

        default:
            goto fail;
    }

    pa_pstream_send_tagstruct(pa_native_connection_get_pstream(c), reply);
    return 0;

fail:

    if (reply)
        pa_tagstruct_free(reply);

    return -1;
}

static pa_hook_result_t connection_unlink_hook_cb(pa_native_protocol *p, pa_native_connection *c, struct userdata *u) {
    pa_assert(p);
    pa_assert(c);
    pa_assert(u);

    pa_idxset_remove_by_data(u->subscribed, c, NULL);
    return PA_HOOK_OK;
}

static void clean_up_db(struct userdata *u) {
    struct clean_up_item {
        PA_LLIST_FIELDS(struct clean_up_item);
        char *entry_name;
        struct entry *entry;
    };

    PA_LLIST_HEAD(struct clean_up_item, to_be_removed);
#ifdef ENABLE_LEGACY_DATABASE_ENTRY_FORMAT
    PA_LLIST_HEAD(struct clean_up_item, to_be_converted);
#endif
    bool done = false;
    pa_datum key;
    struct clean_up_item *item = NULL;
    struct clean_up_item *next = NULL;

    pa_assert(u);

    /* It would be convenient to remove or replace the entries in the database
     * in the same loop that iterates through the database, but modifying the
     * database is not supported while iterating through it. That's why we
     * collect the entries that need to be removed or replaced to these
     * lists. */
    PA_LLIST_HEAD_INIT(struct clean_up_item, to_be_removed);
#ifdef ENABLE_LEGACY_DATABASE_ENTRY_FORMAT
    PA_LLIST_HEAD_INIT(struct clean_up_item, to_be_converted);
#endif

    done = !pa_database_first(u->database, &key, NULL);
    while (!done) {
        pa_datum next_key;
        char *entry_name = NULL;
        struct entry *e = NULL;

        entry_name = pa_xstrndup(key.data, key.size);

        /* Use entry_read() to check whether this entry is valid. */
        if (!(e = entry_read(u, entry_name))) {
            item = pa_xnew0(struct clean_up_item, 1);
            PA_LLIST_INIT(struct clean_up_item, item);
            item->entry_name = entry_name;

#ifdef ENABLE_LEGACY_DATABASE_ENTRY_FORMAT
            /* entry_read() failed, but what about legacy_entry_read()? */
            if (!(e = legacy_entry_read(u, entry_name)))
                /* Not a legacy entry either, let's remove this. */
                PA_LLIST_PREPEND(struct clean_up_item, to_be_removed, item);
            else {
                /* Yay, it's valid after all! Now let's convert the entry to the current format. */
                item->entry = e;
                PA_LLIST_PREPEND(struct clean_up_item, to_be_converted, item);
            }
#else
            /* Invalid entry, let's remove this. */
            PA_LLIST_PREPEND(struct clean_up_item, to_be_removed, item);
#endif
        } else {
            pa_xfree(entry_name);
            entry_free(e);
        }

        done = !pa_database_next(u->database, &key, &next_key, NULL);
        pa_datum_free(&key);
        key = next_key;
    }

    PA_LLIST_FOREACH_SAFE(item, next, to_be_removed) {
        key.data = item->entry_name;
        key.size = strlen(item->entry_name);

        pa_log_debug("Removing an invalid entry: %s", item->entry_name);

        pa_assert_se(pa_database_unset(u->database, &key) >= 0);
        trigger_save(u);

        PA_LLIST_REMOVE(struct clean_up_item, to_be_removed, item);
        pa_xfree(item->entry_name);
        pa_xfree(item);
    }

#ifdef ENABLE_LEGACY_DATABASE_ENTRY_FORMAT
    PA_LLIST_FOREACH_SAFE(item, next, to_be_converted) {
        pa_log_debug("Upgrading a legacy entry to the current format: %s", item->entry_name);

        pa_assert_se(entry_write(u, item->entry_name, item->entry, true));
        trigger_save(u);

        PA_LLIST_REMOVE(struct clean_up_item, to_be_converted, item);
        pa_xfree(item->entry_name);
        entry_free(item->entry);
        pa_xfree(item);
    }
#endif
}

int pa__init(pa_module*m) {
    pa_modargs *ma = NULL;
    struct userdata *u;
    char *state_path;
    pa_sink_input *si;
    pa_source_output *so;
    uint32_t idx;
    bool restore_device = true, restore_volume = true, restore_muted = true;

#ifdef HAVE_DBUS
    pa_datum key;
    bool done;
#endif

    pa_assert(m);

    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
        pa_log("Failed to parse module arguments");
        goto fail;
    }

    if (pa_modargs_get_value_boolean(ma, "restore_device", &restore_device) < 0 ||
        pa_modargs_get_value_boolean(ma, "restore_volume", &restore_volume) < 0 ||
        pa_modargs_get_value_boolean(ma, "restore_muted", &restore_muted) < 0) {
        pa_log("restore_device=, restore_volume= and restore_muted= expect boolean arguments");
        goto fail;
    }

    if (pa_modargs_get_value(ma, "on_hotplug", NULL) != NULL ||
	pa_modargs_get_value(ma, "on_rescue", NULL) != NULL)
        pa_log("on_hotplug and on_rescue are obsolete arguments, please remove them from your configuration");

    if (!restore_muted && !restore_volume && !restore_device)
        pa_log_warn("Neither restoring volume, nor restoring muted, nor restoring device enabled!");

    m->userdata = u = pa_xnew0(struct userdata, 1);
    u->core = m->core;
    u->module = m;
    u->restore_device = restore_device;
    u->restore_volume = restore_volume;
    u->restore_muted = restore_muted;
    u->subscribed = pa_idxset_new(pa_idxset_trivial_hash_func, pa_idxset_trivial_compare_func);

    u->protocol = pa_native_protocol_get(m->core);
    pa_native_protocol_install_ext(u->protocol, m, extension_cb);

    pa_module_hook_connect(m, &pa_native_protocol_hooks(u->protocol)[PA_NATIVE_HOOK_CONNECTION_UNLINK], PA_HOOK_NORMAL, (pa_hook_cb_t) connection_unlink_hook_cb, u);

    u->subscription = pa_subscription_new(m->core, PA_SUBSCRIPTION_MASK_SINK_INPUT|PA_SUBSCRIPTION_MASK_SOURCE_OUTPUT, subscribe_callback, u);

    if (restore_device) {
        /* A little bit earlier than module-intended-roles ... */
        pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SINK_INPUT_NEW], PA_HOOK_EARLY, (pa_hook_cb_t) sink_input_new_hook_callback, u);
        pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_NEW], PA_HOOK_EARLY, (pa_hook_cb_t) source_output_new_hook_callback, u);
    }

    if (restore_volume || restore_muted) {
        pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SINK_INPUT_FIXATE], PA_HOOK_EARLY, (pa_hook_cb_t) sink_input_fixate_hook_callback, u);
        pa_module_hook_connect(m, &m->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_FIXATE], PA_HOOK_EARLY, (pa_hook_cb_t) source_output_fixate_hook_callback, u);
    }

    if (!(state_path = pa_state_path(NULL, true)))
        goto fail;

    if (!(u->database = pa_database_open(state_path, "stream-volumes", true, true))) {
        pa_xfree(state_path);
        goto fail;
    }

    pa_xfree(state_path);

    clean_up_db(u);

    if (fill_db(u, pa_modargs_get_value(ma, "fallback_table", NULL)) < 0)
        goto fail;

#ifdef HAVE_DBUS
    u->dbus_protocol = pa_dbus_protocol_get(u->core);
    u->dbus_entries = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func, NULL, (pa_free_cb_t) dbus_entry_free);

    pa_assert_se(pa_dbus_protocol_add_interface(u->dbus_protocol, OBJECT_PATH, &stream_restore_interface_info, u) >= 0);
    pa_assert_se(pa_dbus_protocol_register_extension(u->dbus_protocol, INTERFACE_STREAM_RESTORE) >= 0);

    /* Create the initial dbus entries. */
    done = !pa_database_first(u->database, &key, NULL);
    while (!done) {
        pa_datum next_key;
        char *name;
        struct dbus_entry *de;

        name = pa_xstrndup(key.data, key.size);
        de = dbus_entry_new(u, name);
        pa_assert_se(pa_hashmap_put(u->dbus_entries, de->entry_name, de) == 0);
        pa_xfree(name);

        done = !pa_database_next(u->database, &key, &next_key, NULL);
        pa_datum_free(&key);
        key = next_key;
    }
#endif

    PA_IDXSET_FOREACH(si, m->core->sink_inputs, idx)
        subscribe_callback(m->core, PA_SUBSCRIPTION_EVENT_SINK_INPUT|PA_SUBSCRIPTION_EVENT_NEW, si->index, u);

    PA_IDXSET_FOREACH(so, m->core->source_outputs, idx)
        subscribe_callback(m->core, PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT|PA_SUBSCRIPTION_EVENT_NEW, so->index, u);

    pa_modargs_free(ma);
    return 0;

fail:
    pa__done(m);

    if (ma)
        pa_modargs_free(ma);

    return -1;
}

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

    pa_assert(m);

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

#ifdef HAVE_DBUS
    if (u->dbus_protocol) {
        pa_assert(u->dbus_entries);

        pa_assert_se(pa_dbus_protocol_unregister_extension(u->dbus_protocol, INTERFACE_STREAM_RESTORE) >= 0);
        pa_assert_se(pa_dbus_protocol_remove_interface(u->dbus_protocol, OBJECT_PATH, stream_restore_interface_info.name) >= 0);

        pa_hashmap_free(u->dbus_entries);

        pa_dbus_protocol_unref(u->dbus_protocol);
    }
#endif

    if (u->subscription)
        pa_subscription_free(u->subscription);

    if (u->save_time_event)
        u->core->mainloop->time_free(u->save_time_event);

    if (u->database)
        pa_database_close(u->database);

    if (u->protocol) {
        pa_native_protocol_remove_ext(u->protocol, m);
        pa_native_protocol_unref(u->protocol);
    }

    if (u->subscribed)
        pa_idxset_free(u->subscribed, NULL);

    pa_xfree(u);
}
