wireplumber/lib/wp/collection.c

/* WirePlumber
 *
 * Copyright © 2026 Collabora Ltd.
 *    @author Julian Bouzas <julian.bouzas@collabora.com>
 *
 * SPDX-License-Identifier: MIT
 */

#include "collection.h"
#include "core.h"
#include "log.h"
#include "error.h"
#include "wpenums.h"

#include <pipewire/impl.h>
#include <pipewire/pipewire.h>
#include <pipewire/extensions/metadata.h>

WP_DEFINE_LOCAL_LOG_TOPIC ("wp-collection")

/*! \defgroup wpcollection WpCollection */
/*!
 * \struct WpCollection
 *
 * The WpCollection class allows accessing the properties and methods of
 * PipeWire collection object (`struct pw_collection`).
 *
 * A WpCollection is constructed internally when a new collection object appears
 * on the PipeWire registry and it is made available through the WpObjectManager
 * API.
 *
 * \gsignals
 *
 * \par global_added
 * \parblock
 * \code
 * void
 * global_added_callback (WpCollection * self,
 *                   guint global_id,
 *                   gpointer user_data)
 * \endcode
 * Emitted when a gobal was added into the collection
 *
 * Parameters:
 * - `global_id` - the added global id
 *
 * Flags: G_SIGNAL_RUN_LAST
 * \endparblock
 *
 * \par global_removed
 * \parblock
 * \code
 * void
 * global_removed_callback (WpCollection * self,
 *                   guint global_id,
 *                   gpointer user_data)
 * \endcode
 * Emitted when a gobal was removed from the collection
 *
 * Parameters:
 * - `global_id` - the removed global id
 *
 * Flags: G_SIGNAL_RUN_LAST
 * \endparblock
 */

enum {
  SIGNAL_GLOBAL_COLLECTED,
  SIGNAL_GLOBAL_DROPPED,
  N_SIGNALS,
};

static guint32 signals[N_SIGNALS] = {0};

/* data structure */

struct item
{
  uint32_t subject;
  gchar *key;
  gchar *type;
  gchar *value;
};

static void
set_item (struct item * item, uint32_t subject, const char * key,
    const char * type, const char * value)
{
  item->subject = subject;
  item->key = key ? g_strdup (key) : NULL;
  item->type = type ? g_strdup (type) : NULL;
  item->value = value ? g_strdup (value) : NULL;
}

static void
clear_item (struct item * item)
{
  g_clear_pointer (&item->key, g_free);
  g_clear_pointer (&item->type, g_free);
  g_clear_pointer (&item->value, g_free);
  spa_zero (*item);
}

static struct item *
find_item (struct pw_array * metadata, uint32_t subject, const char * key)
{
  struct item *item;

  pw_array_for_each (item, metadata) {
    if (item->subject == subject && (key == NULL || !strcmp (item->key, key)))
      return item;
  }
  return NULL;
}

static void
clear_items (struct pw_array * metadata)
{
  struct item *item;

  pw_array_consume (item, metadata) {
    clear_item (item);
    pw_array_remove (metadata, item);
  }
  pw_array_reset (metadata);
}

struct _WpCollection
{
  WpGlobalProxy parent;

  struct pw_metadata *iface;
  struct spa_hook listener;
  struct pw_array metadata;
  gboolean listener_added;
};


G_DEFINE_TYPE (WpCollection, wp_collection, WP_TYPE_GLOBAL_PROXY)

static void
wp_collection_init (WpCollection * self)
{
  pw_array_init (&self->metadata, 4096);
}

static void
wp_collection_finalize (GObject * object)
{
  WpCollection * self = WP_COLLECTION (object);

  pw_array_clear (&self->metadata);

  G_OBJECT_CLASS (wp_collection_parent_class)->finalize (object);
}

static WpObjectFeatures
wp_collection_get_supported_features (WpObject * object)
{
  return WP_PROXY_FEATURE_BOUND | WP_COLLECTION_FEATURE_DATA;
}

enum {
  STEP_BIND = WP_TRANSITION_STEP_CUSTOM_START,
  STEP_CACHE
};

static guint
wp_collection_activate_get_next_step (WpObject * object,
    WpFeatureActivationTransition * transition, guint step,
    WpObjectFeatures missing)
{
  g_return_val_if_fail (
      missing & (WP_PROXY_FEATURE_BOUND | WP_COLLECTION_FEATURE_DATA),
      WP_TRANSITION_STEP_ERROR);

  /* bind if not already bound */
  if (missing & WP_PROXY_FEATURE_BOUND)
    return STEP_BIND;
  else
    return STEP_CACHE;
}

static void
wp_collection_activate_execute_step (WpObject * object,
    WpFeatureActivationTransition * transition, guint step,
    WpObjectFeatures missing)
{
  switch (step) {
  case STEP_CACHE:
    /* just wait for initial_sync_done() */
    break;
  default:
    WP_OBJECT_CLASS (wp_collection_parent_class)->
        activate_execute_step (object, transition, step, missing);
    break;
  }
}

static int
metadata_event_property (void *object, uint32_t subject, const char *key,
    const char *type, const char *value)
{
  WpCollection *self = WP_COLLECTION (object);
  struct item *item = NULL;

  /* Clear subject if key is NULL */
  if (key == NULL) {
    while (true) {
      guint32 global_id = SPA_ID_INVALID;

      item = find_item (&self->metadata, subject, NULL);
      if (item == NULL)
        break;

      pw_array_remove (&self->metadata, item);

      if (spa_atou32 (item->key, &global_id, 0))
        g_signal_emit (self, signals[SIGNAL_GLOBAL_DROPPED], 0, global_id);

      clear_item (item);
    }
    return 0;
  }

  item = find_item (&self->metadata, subject, key);
  if (item == NULL) {
    if (value == NULL)
      return 0;
    item = pw_array_add (&self->metadata, sizeof (*item));
    if (item == NULL)
      return -errno;
  } else {
    clear_item (item);
  }

  if (value != NULL) {
    guint32 global_id = SPA_ID_INVALID;
    set_item (item, subject, key, type, value);
    if (spa_atou32 (key, &global_id, 0))
      g_signal_emit (self, signals[SIGNAL_GLOBAL_COLLECTED], 0, global_id);
  } else {
    guint32 global_id = SPA_ID_INVALID;
    pw_array_remove (&self->metadata, item);
    if (spa_atou32 (key, &global_id, 0))
      g_signal_emit (self, signals[SIGNAL_GLOBAL_DROPPED], 0, global_id);
  }

  return 0;
}

static const struct pw_metadata_events metadata_events = {
  PW_VERSION_METADATA_EVENTS,
  .property = metadata_event_property,
};

static void
wp_collection_pw_proxy_created (WpProxy * proxy, struct pw_proxy * pw_proxy)
{
  WpCollection *self = WP_COLLECTION (proxy);
  g_autoptr (WpCore) core = wp_object_get_core (WP_OBJECT (self));

  self->iface = (struct pw_metadata *) pw_proxy;
  pw_metadata_add_listener (self->iface, &self->listener, &metadata_events,
      self);
  self->listener_added = TRUE;

  wp_object_update_features (WP_OBJECT (self), WP_COLLECTION_FEATURE_DATA, 0);
}

static void
wp_collection_pw_proxy_destroyed (WpProxy * proxy)
{
  WpCollection *self = WP_COLLECTION (proxy);

  if (self->listener_added) {
    spa_hook_remove (&self->listener);
    self->listener_added = FALSE;
  }
  clear_items (&self->metadata);
  wp_object_update_features (WP_OBJECT (self), 0, WP_COLLECTION_FEATURE_DATA);

  WP_PROXY_CLASS (wp_collection_parent_class)->pw_proxy_destroyed (proxy);
}

static void
wp_collection_class_init (WpCollectionClass * klass)
{
  GObjectClass *object_class = (GObjectClass *) klass;
  WpObjectClass *wpobject_class = (WpObjectClass *) klass;
  WpProxyClass *proxy_class = (WpProxyClass *) klass;

  object_class->finalize = wp_collection_finalize;

  wpobject_class->get_supported_features = wp_collection_get_supported_features;
  wpobject_class->activate_get_next_step = wp_collection_activate_get_next_step;
  wpobject_class->activate_execute_step = wp_collection_activate_execute_step;

  proxy_class->pw_iface_type = PW_TYPE_INTERFACE_Metadata;
  proxy_class->pw_iface_version = PW_VERSION_METADATA;
  proxy_class->pw_proxy_created = wp_collection_pw_proxy_created;
  proxy_class->pw_proxy_destroyed = wp_collection_pw_proxy_destroyed;

  signals[SIGNAL_GLOBAL_COLLECTED] = g_signal_new ("global-collected",
      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL,
      G_TYPE_NONE, 1, G_TYPE_UINT);

  signals[SIGNAL_GLOBAL_DROPPED] = g_signal_new ("global-dropped",
      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL,
      G_TYPE_NONE, 1, G_TYPE_UINT);
}

/*!
 * \brief Gets the name of the collection
 *
 * \ingroup wpcollection
 * \param self the collection object
 * \returns (nullable): the name of the collection
 */
const gchar *
wp_collection_get_name (WpCollection * self)
{
  g_autoptr (WpProperties) props = NULL;

  g_return_val_if_fail (WP_IS_COLLECTION (self), NULL);

  props = wp_global_proxy_get_global_properties (WP_GLOBAL_PROXY (self));
  return props ? wp_properties_get (props, "collection.name") : NULL;
}

/*!
 * \brief Gets the total number of globals the collection has collected
 *
 * \ingroup wpcollection
 * \param self the collection object
 * \returns the total number of globals the collection has collected
 */
gsize
wp_collection_get_size (WpCollection * self)
{
  g_return_val_if_fail (WP_IS_COLLECTION (self), 0);

  return pw_array_get_len (&self->metadata, struct item);
}

/*!
 * \brief Checks if a global ID is collected in the collection
 *
 * \ingroup wpcollection
 * \param self the collection object
 * \param global_id the global ID to check
 * \returns TRUE if the global ID is collected in the colleciton, FALSE
 * otherwise.
 */
gboolean
wp_collection_contains_global (WpCollection * self, guint32 global_id)
{
  struct item *item;

  g_return_val_if_fail (WP_IS_COLLECTION (self), FALSE);

  pw_array_for_each (item, &self->metadata) {
    guint32 id = SPA_ID_INVALID;
    if (spa_atou32 (item->key, &id, 0) && id == global_id)
      return TRUE;
  }
  return FALSE;
}

/*!
 * \brief Collects a global ID into the collection.
 *
 * \ingroup wpcollection
 * \param self the collection object
 * \param global_id the global ID to collect
 */
void
wp_collection_collect_global (WpCollection * self, guint32 global_id)
{
  g_autofree gchar *global_id_str = NULL;

  g_return_if_fail (WP_IS_COLLECTION (self));
  g_return_if_fail (global_id != SPA_ID_INVALID);

  global_id_str = g_strdup_printf ("%u", global_id);
  pw_metadata_set_property (self->iface, 0, global_id_str, NULL, "collected");
}

/*!
 * \brief Drops a global ID from the collection.
 *
 * \ingroup wpcollection
 * \param self the collection object
 * \param global_id the global ID to drop
 */
void
wp_collection_drop_global (WpCollection * self, guint32 global_id)
{
  g_autofree gchar *global_id_str = NULL;

  g_return_if_fail (WP_IS_COLLECTION (self));
  g_return_if_fail (global_id != SPA_ID_INVALID);

  global_id_str = g_strdup_printf ("%u", global_id);
  pw_metadata_set_property (self->iface, 0, global_id_str, NULL, NULL);
}

/*!
 * \brief Clears all collected global Ids
 * \ingroup wpcollection
 * \param self the collection object
 */
void
wp_collection_clear (WpCollection * self)
{
  g_return_if_fail (WP_IS_COLLECTION (self));

  pw_metadata_clear (self->iface);
}

struct collection_iterator_data
{
  WpCollection *collection;
  const struct item *item;
};

static void
collection_iterator_reset (WpIterator *it)
{
  struct collection_iterator_data *it_data = wp_iterator_get_user_data (it);
  WpCollection *self = it_data->collection;

  it_data->item = pw_array_first (&self->metadata);
}

static gboolean
collection_iterator_next (WpIterator *it, GValue *item)
{
  struct collection_iterator_data *it_data = wp_iterator_get_user_data (it);
  WpCollection *self = it_data->collection;

  while (pw_array_check (&self->metadata, it_data->item)) {
    guint global_id = SPA_ID_INVALID;
    if (spa_atou32 (it_data->item->key, &global_id, 0)) {
      g_value_init (item, G_TYPE_UINT);
      g_value_set_uint (item, global_id);
      it_data->item++;
      return TRUE;
    }
    it_data->item++;
  }
  return FALSE;
}

static void
collection_iterator_finalize (WpIterator *it)
{
  struct collection_iterator_data *it_data = wp_iterator_get_user_data (it);
  g_object_unref (it_data->collection);
}

static const WpIteratorMethods collection_iterator_methods = {
  .version = WP_ITERATOR_METHODS_VERSION,
  .reset = collection_iterator_reset,
  .next = collection_iterator_next,
  .finalize = collection_iterator_finalize,
};

/*!
 * \brief Iterates over all the collected global IDs.
 *
 * \ingroup wpcollection
 * \param self a collection object
 * \returns (transfer full): an iterator that iterates over the collected global
 *   IDs. The type of the iterator item is an unsigned integer.
 */
WpIterator *
wp_collection_new_iterator (WpCollection * self)
{
  g_autoptr (WpIterator) it = NULL;
  struct collection_iterator_data *it_data;

  g_return_val_if_fail (WP_IS_COLLECTION (self), NULL);

  it = wp_iterator_new (&collection_iterator_methods,
      sizeof (struct collection_iterator_data));
  it_data = wp_iterator_get_user_data (it);
  it_data->collection = g_object_ref (self);
  it_data->item = pw_array_first (&self->metadata);
  return g_steal_pointer (&it);
}

/*!
 * \struct WpImplCollection
 * The implementation side of the collection object.
 *
 * Activate this object with at least WP_PROXY_FEATURE_BOUND to export it to
 * PipeWire.
 */
struct _WpImplCollection
{
  WpProxy parent;

  gchar *name;
  WpProperties *properties;

  struct pw_metadata *iface;
  struct pw_impl_metadata *impl;
  struct spa_hook listener;
  struct pw_array metadata;
};

enum {
  PROP_0,
  PROP_NAME,
  PROP_PROPERTIES,
};

enum {
  IMPL_SIGNAL_GLOBAL_COLLECTED,
  IMPL_SIGNAL_GLOBAL_DROPPED,
  IMPL_N_SIGNALS,
};

static guint32 impl_signals[IMPL_N_SIGNALS] = {0};

G_DEFINE_TYPE (WpImplCollection, wp_impl_collection, WP_TYPE_PROXY)

static void
wp_impl_collection_init (WpImplCollection * self)
{
  pw_array_init (&self->metadata, 4096);
}

static int
impl_metadata_event_property (void *object, uint32_t subject, const char *key,
    const char *type, const char *value)
{
  WpImplCollection *self = WP_IMPL_COLLECTION (object);
  struct item *item = NULL;

  /* Clear subject if key is NULL */
  if (key == NULL) {
    while (true) {
      guint32 global_id = SPA_ID_INVALID;

      item = find_item (&self->metadata, subject, NULL);
      if (item == NULL)
        break;

      pw_array_remove (&self->metadata, item);

      if (spa_atou32 (item->key, &global_id, 0))
        g_signal_emit (self, impl_signals[IMPL_SIGNAL_GLOBAL_DROPPED], 0,
            global_id);

      clear_item (item);
    }
    return 0;
  }

  item = find_item (&self->metadata, subject, key);
  if (item == NULL) {
    if (value == NULL)
      return 0;
    item = pw_array_add (&self->metadata, sizeof (*item));
    if (item == NULL)
      return -errno;
  } else {
    clear_item (item);
  }

  if (value != NULL) {
    guint32 global_id = SPA_ID_INVALID;
    set_item (item, subject, key, type, value);
    if (spa_atou32 (key, &global_id, 0))
      g_signal_emit (self, impl_signals[IMPL_SIGNAL_GLOBAL_COLLECTED], 0,
          global_id);
  } else {
    guint32 global_id = SPA_ID_INVALID;
    pw_array_remove (&self->metadata, item);
    if (spa_atou32 (key, &global_id, 0))
      g_signal_emit (self, impl_signals[IMPL_SIGNAL_GLOBAL_DROPPED], 0,
          global_id);
  }

  return 0;
}

static const struct pw_impl_metadata_events impl_metadata_events = {
  PW_VERSION_IMPL_METADATA_EVENTS,
  .property = impl_metadata_event_property,
};

static void
wp_impl_collection_constructed (GObject *object)
{
  WpImplCollection *self = WP_IMPL_COLLECTION (object);
  g_autoptr (WpCore) core = NULL;
  struct pw_context *pw_context;
  struct pw_properties *props;

  core = wp_object_get_core (WP_OBJECT (self));
  g_return_if_fail (core);
  pw_context = wp_core_get_pw_context (core);
  g_return_if_fail (pw_context);

  /* Make sure the collection name and flag is set */
  if (!self->properties)
    self->properties = wp_properties_new_empty ();
  wp_properties_set (self->properties, "collection.name", self->name);
  wp_properties_set (self->properties, "wireplumber.collection", "true");

  props = wp_properties_to_pw_properties (self->properties);
  self->impl = pw_context_create_metadata (pw_context, self->name, props , 0);
  g_return_if_fail (self->impl);
  self->iface = pw_impl_metadata_get_implementation (self->impl);
  g_return_if_fail (self->iface);

  pw_impl_metadata_add_listener (self->impl, &self->listener,
      &impl_metadata_events, self);

  G_OBJECT_CLASS (wp_impl_collection_parent_class)->constructed (object);
}

static void
wp_impl_collection_finalize (GObject * object)
{
  WpImplCollection *self = WP_IMPL_COLLECTION (object);

  pw_array_clear (&self->metadata);
  spa_hook_remove (&self->listener);
  g_clear_pointer (&self->impl, pw_impl_metadata_destroy);
  g_clear_pointer (&self->properties, wp_properties_unref);
  g_clear_pointer (&self->name, g_free);

  G_OBJECT_CLASS (wp_impl_collection_parent_class)->finalize (object);
}

static void
wp_impl_collection_set_property (GObject * object, guint property_id,
    const GValue * value, GParamSpec * pspec)
{
  WpImplCollection *self = WP_IMPL_COLLECTION (object);

  switch (property_id) {
  case PROP_NAME:
    g_clear_pointer (&self->name, g_free);
    self->name = g_value_dup_string (value);
    break;
  case PROP_PROPERTIES:
    g_clear_pointer (&self->properties, wp_properties_unref);
    self->properties = g_value_dup_boxed (value);
    break;
  default:
    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
    break;
  }
}

static void
wp_impl_collection_get_property (GObject * object, guint property_id,
    GValue * value, GParamSpec * pspec)
{
  WpImplCollection *self = WP_IMPL_COLLECTION (object);

  switch (property_id) {
  case PROP_NAME:
    g_value_set_string (value, self->name);
    break;
  case PROP_PROPERTIES:
    g_value_set_boxed (value, self->properties);
    break;
  default:
    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
    break;
  }
}

enum {
  STEP_EXPORT = WP_TRANSITION_STEP_CUSTOM_START,
};

static WpObjectFeatures
wp_impl_collection_get_supported_features (WpObject * object)
{
  return WP_PROXY_FEATURE_BOUND;
}

static guint
wp_impl_collection_activate_get_next_step (WpObject * object,
    WpFeatureActivationTransition * transition, guint step,
    WpObjectFeatures missing)
{
  g_return_val_if_fail (missing & (WP_PROXY_FEATURE_BOUND),
      WP_TRANSITION_STEP_ERROR);

  return STEP_EXPORT;
}

static void
wp_impl_collection_activate_execute_step (WpObject * object,
    WpFeatureActivationTransition * transition, guint step,
    WpObjectFeatures missing)
{
  WpImplCollection *self = WP_IMPL_COLLECTION (object);

  switch (step) {
  case STEP_EXPORT: {
    g_autoptr (WpCore) core = wp_object_get_core (object);
    struct pw_core *pw_core = wp_core_get_pw_core (core);
    const struct pw_properties *props = NULL;

    /* no pw_core -> we are not connected */
    if (!pw_core) {
      wp_transition_return_error (WP_TRANSITION (transition), g_error_new (
              WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_OPERATION_FAILED,
              "The WirePlumber core is not connected; "
              "object cannot be exported to PipeWire"));
      return;
    }

    props = pw_impl_metadata_get_properties (self->impl);
    wp_proxy_set_pw_proxy (WP_PROXY (self), pw_core_export (pw_core,
            PW_TYPE_INTERFACE_Metadata, &props->dict, self->iface, 0));
    break;
  }
  default:
    WP_OBJECT_CLASS (wp_impl_collection_parent_class)->
        activate_execute_step (object, transition, step, missing);
    break;
  }
}

static void
wp_impl_collection_class_init (WpImplCollectionClass * klass)
{
  GObjectClass *object_class = (GObjectClass *) klass;
  WpObjectClass *wpobject_class = (WpObjectClass *) klass;
  WpProxyClass *proxy_class = (WpProxyClass *) klass;

  object_class->constructed = wp_impl_collection_constructed;
  object_class->finalize = wp_impl_collection_finalize;
  object_class->set_property = wp_impl_collection_set_property;
  object_class->get_property = wp_impl_collection_get_property;

  wpobject_class->get_supported_features =
      wp_impl_collection_get_supported_features;
  wpobject_class->activate_get_next_step =
      wp_impl_collection_activate_get_next_step;
  wpobject_class->activate_execute_step =
      wp_impl_collection_activate_execute_step;

  proxy_class->pw_iface_type = PW_TYPE_INTERFACE_Metadata;
  proxy_class->pw_iface_version = PW_VERSION_METADATA;

  g_object_class_install_property (object_class, PROP_NAME,
      g_param_spec_string ("name", "name", "The collection name", NULL,
          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (object_class, PROP_PROPERTIES,
      g_param_spec_boxed ("properties", "properties",
          "The collection properties", WP_TYPE_PROPERTIES,
          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));

  impl_signals[IMPL_SIGNAL_GLOBAL_COLLECTED] = g_signal_new ("global-collected",
      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL,
      G_TYPE_NONE, 1, G_TYPE_UINT);

  impl_signals[IMPL_SIGNAL_GLOBAL_DROPPED] = g_signal_new ("global-dropped",
      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL,
      G_TYPE_NONE, 1, G_TYPE_UINT);
}

/*!
 * \brief Creates a new impl collection
 * \ingroup wpcollection
 * \param core the core
 * \param name (nullable): the collection name
 * \param properties (nullable) (transfer full): the collection properties
 * \returns (transfer full): a new WpImplCollection
 */
WpImplCollection *
wp_impl_collection_new (WpCore * core, const gchar *name,
    WpProperties *properties)
{
  g_autoptr (WpProperties) props = properties;

  g_return_val_if_fail (WP_IS_CORE (core), NULL);

  return g_object_new (WP_TYPE_IMPL_COLLECTION,
      "core", core,
      "name", name,
      "properties", props,
      NULL);
}

/*!
 * \brief Gets the properties of the impl collection
 *
 * \ingroup wpcollection
 * \param self the impl collection object
 \returns (transfer full) (nullable): the properties of the impl collection
 */
WpProperties *
wp_impl_collection_get_properties (WpImplCollection *self)
{
  g_return_val_if_fail (WP_IS_IMPL_COLLECTION (self), NULL);

  return self->properties ? wp_properties_ref (self->properties) : NULL;
}

/*!
 * \brief Gets the name of the impl collection
 *
 * \ingroup wpcollection
 * \param self the impl collection object
 * \returns (nullable): the name of the impl collection
 */
const gchar *
wp_impl_collection_get_name (WpImplCollection *self)
{
  g_return_val_if_fail (WP_IS_IMPL_COLLECTION (self), NULL);

  return self->name;
}

/*!
 * \brief Gets the total number of globals the impl collection has collected
 *
 * \ingroup wpcollection
 * \param self the impl collection object
 * \returns the total number of globals the impl collection has collected
 */
gsize
wp_impl_collection_get_size (WpImplCollection * self)
{
  g_return_val_if_fail (WP_IS_IMPL_COLLECTION (self), 0);

  return pw_array_get_len (&self->metadata, struct item);
}

/*!
 * \brief Checks if a global ID is collected in the impl collection
 *
 * \ingroup wpcollection
 * \param self the impl collection object
 * \param global_id the global ID to check
 * \returns TRUE if the global ID is collected in the colleciton, FALSE
 * otherwise.
 */
gboolean
wp_impl_collection_contains_global (WpImplCollection * self, guint32 global_id)
{
  struct item *item;

  g_return_val_if_fail (WP_IS_IMPL_COLLECTION (self), FALSE);

  pw_array_for_each (item, &self->metadata) {
    guint32 id = SPA_ID_INVALID;
    if (spa_atou32 (item->key, &id, 0) && id == global_id)
      return TRUE;
  }
  return FALSE;
}

/*!
 * \brief Collects a global ID into the impl collection.
 *
 * \ingroup wpcollection
 * \param self the impl collection object
 * \param global_id the global ID to collect
 */
void
wp_impl_collection_collect_global (WpImplCollection * self, guint32 global_id)
{
  g_autofree gchar *global_id_str = NULL;

  g_return_if_fail (WP_IS_IMPL_COLLECTION (self));
  g_return_if_fail (global_id != SPA_ID_INVALID);

  global_id_str = g_strdup_printf ("%u", global_id);
  pw_metadata_set_property (self->iface, 0, global_id_str, NULL, "collected");
}

/*!
 * \brief Drops a global ID from the impl collection.
 *
 * \ingroup wpcollection
 * \param self the impl collection object
 * \param global_id the global ID to drop
 */
void
wp_impl_collection_drop_global (WpImplCollection * self, guint32 global_id)
{
  g_autofree gchar *global_id_str = NULL;

  g_return_if_fail (WP_IS_IMPL_COLLECTION (self));
  g_return_if_fail (global_id != SPA_ID_INVALID);

  global_id_str = g_strdup_printf ("%u", global_id);
  pw_metadata_set_property (self->iface, 0, global_id_str, NULL, NULL);
}

/*!
 * \brief Clears all collected global Ids
 * \ingroup wpcollection
 * \param self the impl collection object
 */
void
wp_impl_collection_clear (WpImplCollection * self)
{
  g_return_if_fail (WP_IS_IMPL_COLLECTION (self));

  pw_metadata_clear (self->iface);
}

struct impl_collection_iterator_data
{
  WpImplCollection *impl_collection;
  const struct item *item;
};

static void
impl_collection_iterator_reset (WpIterator *it)
{
  struct impl_collection_iterator_data *it_data =
      wp_iterator_get_user_data (it);
  WpImplCollection *self = it_data->impl_collection;

  it_data->item = pw_array_first (&self->metadata);
}

static gboolean
impl_collection_iterator_next (WpIterator *it, GValue *item)
{
  struct impl_collection_iterator_data *it_data =
      wp_iterator_get_user_data (it);
  WpImplCollection *self = it_data->impl_collection;

  while (pw_array_check (&self->metadata, it_data->item)) {
    guint global_id = SPA_ID_INVALID;
    if (spa_atou32 (it_data->item->key, &global_id, 0)) {
      g_value_init (item, G_TYPE_UINT);
      g_value_set_uint (item, global_id);
      it_data->item++;
      return TRUE;
    }
    it_data->item++;
  }
  return FALSE;
}

static void
impl_collection_iterator_finalize (WpIterator *it)
{
  struct impl_collection_iterator_data *it_data =
      wp_iterator_get_user_data (it);
  g_object_unref (it_data->impl_collection);
}

static const WpIteratorMethods impl_collection_iterator_methods = {
  .version = WP_ITERATOR_METHODS_VERSION,
  .reset = impl_collection_iterator_reset,
  .next = impl_collection_iterator_next,
  .finalize = impl_collection_iterator_finalize,
};

/*!
 * \brief Iterates over all the collected global IDs.
 *
 * \ingroup wpcollection
 * \param self an impl collection object
 * \returns (transfer full): an iterator that iterates over the collected global
 *   IDs. The type of the iterator item is an unsigned integer.
 */
WpIterator *
wp_impl_collection_new_iterator (WpImplCollection * self)
{
  g_autoptr (WpIterator) it = NULL;
  struct impl_collection_iterator_data *it_data;

  g_return_val_if_fail (WP_IS_IMPL_COLLECTION (self), NULL);

  it = wp_iterator_new (&impl_collection_iterator_methods,
      sizeof (struct impl_collection_iterator_data));
  it_data = wp_iterator_get_user_data (it);
  it_data->impl_collection = g_object_ref (self);
  it_data->item = pw_array_first (&self->metadata);
  return g_steal_pointer (&it);
}