feat: wireplumber support

Adds basic support for showing volume via wireplumber. Allows specifying
the node-id or falling back to the default Audio/Sink node id if node-id
is not set. If tooltip on hover is enabled, will show `{node_name}` by
default otherwise `tooltip-format`.

Format replacements:

`{volume}` - Volume in percentage
`{node_name}` - The node's nickname (`node.nick` property)

src/factory.cpp

@@ -137,6 +137,11 @@ waybar::AModule* waybar::Factory::makeModule(const std::string& name) const {
     if (ref == "jack") {
       return new waybar::modules::JACK(id, config_[name]);
     }
+#endif
+#ifdef HAVE_LIBWIREPLUMBER
+    if (ref == "wireplumber") {
+      return new waybar::modules::Wireplumber(id, config_[name]);
+    }
 #endif
     if (ref == "temperature") {
       return new waybar::modules::Temperature(id, config_[name]);

src/modules/wireplumber.cpp

@@ -0,0 +1,172 @@
+#include "modules/wireplumber.hpp"
+
+waybar::modules::Wireplumber::Wireplumber(const std::string &id, const Json::Value &config)
+    : AButton(config, "wireplumber", id, "{volume}%"),
+      wp_core_(nullptr),
+      apis_(nullptr),
+      om_(nullptr),
+      pending_plugins_(0),
+      muted_(false),
+      volume_(0.0),
+      node_id_(0) {
+        wp_init(WP_INIT_ALL);
+        wp_core_ = wp_core_new(NULL, NULL);
+        apis_ = g_ptr_array_new_with_free_func(g_object_unref);
+        om_ = wp_object_manager_new();
+
+        prepare();
+
+        loadRequiredApiModules();
+
+        if (!wp_core_connect(wp_core_)) {
+          throw std::runtime_error("Could not connect to PipeWire\n");
+        }
+
+        g_signal_connect_swapped(om_, "installed", (GCallback)onObjectManagerInstalled, this);
+        
+        activatePlugins();
+        
+        dp.emit();
+      }
+
+waybar::modules::Wireplumber::~Wireplumber() {
+  g_clear_pointer(&apis_, g_ptr_array_unref);
+  g_clear_object(&om_);
+  g_clear_object(&wp_core_);
+
+}
+
+uint32_t waybar::modules::Wireplumber::getDefaultNodeId(waybar::modules::Wireplumber* self) {
+  uint32_t id;
+  g_autoptr(WpPlugin) def_nodes_api = wp_plugin_find(self->wp_core_, "default-nodes-api");
+
+  if (!def_nodes_api) {
+    throw std::runtime_error("Default nodes API is not loaded\n");
+  }
+
+  g_signal_emit_by_name(def_nodes_api, "get-default-node", "Audio/Sink", &id);
+
+  if (id <= 0 || id >= G_MAXUINT32) {
+    auto err = fmt::format("'{}' is not a valid ID (returned by default-nodes-api)\n", id);
+    throw std::runtime_error(err);
+  }
+
+  return id;
+}
+
+void waybar::modules::Wireplumber::updateNodeName(waybar::modules::Wireplumber* self) {
+  auto proxy = static_cast<WpPipewireObject *>(wp_object_manager_lookup(self->om_, WP_TYPE_GLOBAL_PROXY, WP_CONSTRAINT_TYPE_PW_GLOBAL_PROPERTY, "object.id", "=u", self->node_id_, NULL));
+
+  if (!proxy) {
+    throw std::runtime_error(fmt::format("Object '{}' not found\n", self->node_id_));
+  }
+
+  g_autoptr(WpProperties) properties = wp_pipewire_object_get_properties(proxy);
+  properties = wp_properties_ensure_unique_owner(properties);
+  self->node_name_ = wp_properties_get(properties, "node.nick");
+}
+
+void waybar::modules::Wireplumber::updateVolume(waybar::modules::Wireplumber* self) {
+  double vol;
+  GVariant* variant = NULL;
+  g_autoptr(WpPlugin) mixer_api = wp_plugin_find(self->wp_core_, "mixer-api");
+  g_signal_emit_by_name(mixer_api, "get-volume", self->node_id_, &variant);
+  if (!variant) {
+    auto err = fmt::format("Node {} does not support volume\n", self->node_id_);
+    throw std::runtime_error(err);
+  }
+
+  g_variant_lookup(variant, "volume", "d", &vol);
+  g_variant_lookup(variant, "mute", "b", &self->muted_);
+  g_clear_pointer(&variant, g_variant_unref);
+
+  self->volume_ = std::round(vol * 100.0F);
+  self->dp.emit();
+}
+
+void waybar::modules::Wireplumber::onObjectManagerInstalled(waybar::modules::Wireplumber* self) {
+  self->node_id_ = self->config_["node-id"].isInt() ? self->config_["node-id"].asInt() : getDefaultNodeId(self);
+
+  g_autoptr(WpPlugin) mixer_api = wp_plugin_find(self->wp_core_, "mixer-api");
+
+  updateVolume(self);
+  updateNodeName(self);
+  g_signal_connect_swapped(mixer_api, "changed", (GCallback)updateVolume, self);
+}
+
+void waybar::modules::Wireplumber::onPluginActivated(WpObject* p, GAsyncResult* res, waybar::modules::Wireplumber* self) {
+  g_autoptr(GError) error = NULL;
+
+  if (!wp_object_activate_finish(p, res, &error)) {
+    throw std::runtime_error(error->message);
+  }
+
+  if (--self->pending_plugins_ == 0) {
+    wp_core_install_object_manager(self->wp_core_, self->om_);
+  }
+}
+
+void waybar::modules::Wireplumber::activatePlugins() {
+  for (uint16_t i = 0; i < apis_->len; i++) {
+    WpPlugin* plugin = static_cast<WpPlugin *>(g_ptr_array_index(apis_, i));
+    pending_plugins_++;
+    wp_object_activate(WP_OBJECT(plugin), WP_PLUGIN_FEATURE_ENABLED, NULL, (GAsyncReadyCallback)onPluginActivated, this);
+  }
+}
+
+void waybar::modules::Wireplumber::prepare() {
+  wp_object_manager_add_interest(om_, WP_TYPE_NODE, NULL);
+  wp_object_manager_request_object_features(om_, WP_TYPE_GLOBAL_PROXY, WP_PIPEWIRE_OBJECT_FEATURES_MINIMAL);
+}
+
+void waybar::modules::Wireplumber::loadRequiredApiModules() {
+  g_autoptr(GError) error = NULL;
+
+  if (!wp_core_load_component(wp_core_, "libwireplumber-module-default-nodes-api", "module", NULL, &error)) {
+    throw std::runtime_error(error->message);
+  }
+
+  if (!wp_core_load_component(wp_core_, "libwireplumber-module-mixer-api", "module", NULL, &error)) {
+    throw std::runtime_error(error->message);
+  }
+
+  g_ptr_array_add(apis_, wp_plugin_find(wp_core_, "default-nodes-api"));
+  g_ptr_array_add (apis_, ({
+    WpPlugin *p = wp_plugin_find(wp_core_, "mixer-api");
+    g_object_set (G_OBJECT (p), "scale", 1 /* cubic */, NULL);
+    p;
+  }));
+}
+
+auto waybar::modules::Wireplumber::update() -> void {
+  auto format = format_;
+  std::string tooltip_format;
+
+  if (muted_) {
+    format = config_["format-muted"].isString() ? config_["format-muted"].asString() : format;
+    button_.get_style_context()->add_class("muted");
+  } else {
+    button_.get_style_context()->remove_class("muted");
+  }
+
+  std::string markup = fmt::format(format, fmt::arg("node_name", node_name_), fmt::arg("volume", volume_));
+  label_->set_markup(markup);
+
+  getState(volume_);
+
+  if (tooltipEnabled()) {
+    if (tooltip_format.empty() && config_["tooltip-format"].isString()) {
+      tooltip_format = config_["tooltip-format"].asString();
+    }
+
+    if (!tooltip_format.empty()) {
+      button_.set_tooltip_text(fmt::format(
+          tooltip_format, fmt::arg("node_name", node_name_), fmt::arg("volume", volume_)));
+    } else {
+      button_.set_tooltip_text(node_name_);
+    }
+  }
+
+  // Call parent update
+  AButton::update();
+}