Repurpose into VIS clientmarlin

Repurpose repository for a spiritual successor of the previous
binding.  The replacement is a daemon that demonstrates servicing
the volume actuator from the VSS schema via VIS signals from
KUKSA.val.  Currently the connection to KUKSA.val is websocket based
using the boost::asio framework, but the plan is to migrate to gRPC
as that becomes more robust in KUKSA.val.  As well, this new code
will serve as the base for implementing a gRPC API to expose the full
set of WirePlumber controls as was done with the previous binding.

Notable changes:
- New code is completely C++, partly to leverage using Boost, but
  also to futureproof future work with gRPC.  The WirePlumber
  interfacing code that has been kept from the old binding is
  still C for now, converting it to C++ is a planned future
  rework.
- Switch from CMake to meson for ease of development and some
  degree of futureproofing.
- Use with systemd is assumed; behavior follows the systemd
  daemon guidelines barring the use of journald logging prefixes,
  which may be addressed with future work.  A systemd unit is
  also installed as part of the build.
- SPDX license headers using SPDX "short identifiers" are used in
  source files rather than the full copyright headers used in the
  previous codebase.  This follows the direction that projects such
  as the Linux kernel are going in.

Bug-AGL: SPEC-4409

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: Ibb7091c4354432bb094147d1419ab475486a4abc

1 files changed, 463 insertions, 0 deletions

diff --git a/src/audiomixer.c b/src/audiomixer.c
new file mode 100644
index 0000000..a40a38e
--- /dev/null
+++ b/src/audiomixer.c
@@ -0,0 +1,463 @@
+/*
+ * Copyright © 2019 Collabora Ltd.
+ *   @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "audiomixer.h"
+#include <wp/wp.h>
+#include <pipewire/pipewire.h>
+
+struct audiomixer
+{
+	WpCore *core;
+	GMainLoop *loop;
+	GMainContext *context;
+	GThread *thread;
+	GMutex lock;
+	GCond cond;
+
+	GPtrArray *mixer_controls;
+
+	gint initialized;
+	WpObjectManager *om;
+	WpPlugin *default_nodes_api;
+	WpPlugin *mixer_api;
+
+	const struct audiomixer_events *events;
+	void *events_data;
+};
+
+struct mixer_control_impl
+{
+	struct mixer_control pub;
+	guint32 node_id;
+};
+
+struct action
+{
+	struct audiomixer *audiomixer;
+	union {
+		struct {
+			guint32 id;
+			gfloat volume;
+		} change_volume;
+		struct {
+			guint32 id;
+			gboolean mute;
+		} change_mute;
+	};
+};
+
+static gboolean
+get_mixer_controls (struct audiomixer * self, guint32 node_id, gdouble * vol, gboolean * mute)
+{
+	g_autoptr (GVariant) v = NULL;
+	g_signal_emit_by_name (self->mixer_api, "get-volume", node_id, &v);
+	return v &&
+		g_variant_lookup (v, "volume", "d", vol) &&
+		g_variant_lookup (v, "mute", "b", mute);
+}
+
+static void
+add_control (struct audiomixer *self, const char *name, guint32 node_id)
+{
+	struct mixer_control_impl *mixctl = NULL;
+	gdouble volume = 1.0;
+	gboolean mute = FALSE;
+
+	/* get current values */
+	if (!get_mixer_controls (self, node_id, &volume, &mute)) {
+		g_warning ("failed to get object controls when populating controls");
+		return;
+	}
+
+	/* create the control */
+	mixctl = g_new0 (struct mixer_control_impl, 1);
+	snprintf (mixctl->pub.name, sizeof (mixctl->pub.name), "%s", name);
+	mixctl->pub.volume = volume;
+	mixctl->pub.mute = mute;
+	mixctl->node_id = node_id;
+	g_ptr_array_add (self->mixer_controls, mixctl);
+
+	g_debug ("added control %s", mixctl->pub.name);
+}
+
+static void
+volume_changed (struct audiomixer * self, guint32 node_id)
+{
+	g_autoptr (GMutexLocker) locker = g_mutex_locker_new (&self->lock);
+	gdouble vol = 1.0;
+	gboolean mute = FALSE;
+
+	for (guint i = 0; i < self->mixer_controls->len; i++) {
+		struct mixer_control_impl *ctl;
+		guint change_mask = 0;
+
+		ctl = g_ptr_array_index (self->mixer_controls, i);
+		if (ctl->node_id != node_id)
+			continue;
+
+		if (!get_mixer_controls (self, node_id, &vol, &mute)) {
+			g_warning ("failed to get object controls when volume changed");
+			return;
+		}
+
+		if ((ctl->pub.volume - 0.01f) > vol || (ctl->pub.volume + 0.01f) < vol) {
+			ctl->pub.volume = vol;
+			change_mask |= MIXER_CONTROL_CHANGE_FLAG_VOLUME;
+		}
+		if (ctl->pub.mute != mute) {
+			ctl->pub.mute = mute;
+			change_mask |= MIXER_CONTROL_CHANGE_FLAG_MUTE;
+		}
+
+		if (self->events && self->events->value_changed)
+			self->events->value_changed (self->events_data, change_mask, &ctl->pub);
+		break;
+	}
+}
+
+static void
+rescan_controls (struct audiomixer * self)
+{
+	g_autoptr (GMutexLocker) locker = g_mutex_locker_new (&self->lock);
+	g_autoptr (WpIterator) it = NULL;
+	g_auto (GValue) val = G_VALUE_INIT;
+	guint32 id = -1;
+
+	g_debug ("rescan");
+
+	/* clear previous */
+	g_ptr_array_set_size (self->mixer_controls, 0);
+
+	/* add master controls */
+	g_signal_emit_by_name (self->default_nodes_api, "get-default-node",
+			"Audio/Sink", &id);
+	if (id != (guint32)-1)
+		add_control (self, "Master Playback", id);
+
+	g_signal_emit_by_name (self->default_nodes_api, "get-default-node",
+			"Audio/Source", &id);
+	if (id != (guint32)-1)
+		add_control (self, "Master Capture", id);
+
+	/* add endpoints */
+	it = wp_object_manager_new_iterator (self->om);
+	for (; wp_iterator_next (it, &val); g_value_unset (&val)) {
+		WpPipewireObject *ep = g_value_get_object (&val);
+		const gchar *name = wp_pipewire_object_get_property (ep, "endpoint.description");
+		const gchar *node = wp_pipewire_object_get_property (ep, "node.id");
+		id = node ? atoi(node) : 0;
+		if (name && id != 0 && id != (guint32)-1)
+			add_control (self, name, id);
+	}
+
+	/* notify subscribers */
+	if (self->events && self->events->controls_changed)
+		self->events->controls_changed (self->events_data);
+	g_cond_broadcast (&self->cond);
+}
+
+static void
+on_default_nodes_activated (WpObject * p, GAsyncResult * res, struct audiomixer * self)
+{
+	g_autoptr (GError) error = NULL;
+	if (!wp_object_activate_finish (p, res, &error)) {
+		g_warning ("%s", error->message);
+	}
+
+	if (wp_object_get_active_features (WP_OBJECT (self->mixer_api))
+			& WP_PLUGIN_FEATURE_ENABLED)
+		wp_core_install_object_manager (self->core, self->om);
+
+	g_signal_connect_swapped (self->default_nodes_api, "changed",
+		(GCallback) rescan_controls, self);
+}
+
+static void
+on_mixer_activated (WpObject * p, GAsyncResult * res, struct audiomixer * self)
+{
+	g_autoptr (GError) error = NULL;
+	if (!wp_object_activate_finish (p, res, &error)) {
+		g_warning ("%s", error->message);
+	}
+
+	if (wp_object_get_active_features (WP_OBJECT (self->default_nodes_api))
+			& WP_PLUGIN_FEATURE_ENABLED)
+		wp_core_install_object_manager (self->core, self->om);
+
+	g_signal_connect_swapped (self->mixer_api, "changed",
+		(GCallback) volume_changed, self);
+}
+
+static void
+on_core_connected (struct audiomixer * self)
+{
+	self->om = wp_object_manager_new ();
+	wp_object_manager_add_interest (self->om, WP_TYPE_ENDPOINT,
+		WP_CONSTRAINT_TYPE_PW_GLOBAL_PROPERTY,
+		PW_KEY_MEDIA_CLASS, "#s", "Audio/*", NULL);
+	wp_object_manager_request_object_features (self->om,
+		WP_TYPE_ENDPOINT, WP_OBJECT_FEATURES_ALL);
+	g_signal_connect_swapped (self->om, "objects-changed",
+		(GCallback) rescan_controls, self);
+
+	wp_object_activate (WP_OBJECT (self->default_nodes_api),
+		WP_PLUGIN_FEATURE_ENABLED, NULL,
+		(GAsyncReadyCallback) on_default_nodes_activated, self);
+
+	wp_object_activate (WP_OBJECT (self->mixer_api),
+		WP_PLUGIN_FEATURE_ENABLED, NULL,
+		(GAsyncReadyCallback) on_mixer_activated, self);
+}
+
+static void
+on_core_disconnected (struct audiomixer * self)
+{
+	g_ptr_array_set_size (self->mixer_controls, 0);
+	g_clear_object (&self->om);
+	g_signal_handlers_disconnect_by_data (self->default_nodes_api, self);
+	g_signal_handlers_disconnect_by_data (self->mixer_api, self);
+	wp_object_deactivate (WP_OBJECT (self->default_nodes_api), WP_PLUGIN_FEATURE_ENABLED);
+	wp_object_deactivate (WP_OBJECT (self->mixer_api), WP_PLUGIN_FEATURE_ENABLED);
+}
+
+static void
+audiomixer_init_in_thread (struct audiomixer * self)
+{
+	g_autoptr (GMutexLocker) locker = g_mutex_locker_new (&self->lock);
+	g_autoptr (GError) error = NULL;
+
+	self->context = g_main_context_new ();
+	g_main_context_push_thread_default (self->context);
+
+	self->loop = g_main_loop_new (self->context, FALSE);
+	self->core = wp_core_new (self->context, NULL);
+
+	/* load required API modules */
+	if (!wp_core_load_component (self->core,
+			"libwireplumber-module-default-nodes-api", "module", NULL, &error)) {
+		g_warning ("%s", error->message);
+		self->initialized = -1;
+		goto out;
+	}
+	if (!wp_core_load_component (self->core,
+			"libwireplumber-module-mixer-api", "module", NULL, &error)) {
+		g_warning ("%s", error->message);
+		self->initialized = -1;
+		goto out;
+	}
+
+	self->default_nodes_api = wp_plugin_find (self->core, "default-nodes-api");
+	self->mixer_api = wp_plugin_find (self->core, "mixer-api");
+	g_object_set (G_OBJECT (self->mixer_api), "scale", 1 /* cubic */, NULL);
+
+	g_signal_connect_swapped (self->core, "connected",
+		G_CALLBACK (on_core_connected), self);
+	g_signal_connect_swapped (self->core, "disconnected",
+		G_CALLBACK (on_core_disconnected), self);
+
+	self->initialized = 1;
+
+out:
+	g_cond_broadcast (&self->cond);
+}
+
+static void *
+audiomixer_thread (struct audiomixer * self)
+{
+	audiomixer_init_in_thread (self);
+
+	/* main loop for the thread; quits only when audiomixer_free() is called */
+	g_main_loop_run (self->loop);
+
+	wp_core_disconnect (self->core);
+	g_clear_object (&self->default_nodes_api);
+	g_clear_object (&self->mixer_api);
+	g_object_unref (self->core);
+
+	g_main_context_pop_thread_default (self->context);
+	g_main_loop_unref (self->loop);
+	g_main_context_unref (self->context);
+
+	return NULL;
+}
+
+struct audiomixer *
+audiomixer_new (void)
+{
+	struct audiomixer *self = calloc(1, sizeof(struct audiomixer));
+
+	wp_init (WP_INIT_ALL);
+
+	g_mutex_init (&self->lock);
+	g_cond_init (&self->cond);
+	self->mixer_controls = g_ptr_array_new_with_free_func (g_free);
+
+	g_mutex_lock (&self->lock);
+	self->initialized = 0;
+	self->thread = g_thread_new ("audiomixer", (GThreadFunc) audiomixer_thread,
+		self);
+	while (self->initialized == 0)
+		g_cond_wait (&self->cond, &self->lock);
+	g_mutex_unlock (&self->lock);
+
+	return self;
+}
+
+void
+audiomixer_free(struct audiomixer *self)
+{
+	g_main_loop_quit (self->loop);
+	g_thread_join (self->thread);
+
+	g_ptr_array_unref (self->mixer_controls);
+	g_cond_clear (&self->cond);
+	g_mutex_clear (&self->lock);
+
+	free (self);
+}
+
+void
+audiomixer_lock(struct audiomixer *self)
+{
+	g_mutex_lock (&self->lock);
+}
+
+void
+audiomixer_unlock(struct audiomixer *self)
+{
+	g_mutex_unlock (&self->lock);
+}
+
+static gboolean
+do_connect (WpCore * core)
+{
+	if (!wp_core_connect (core))
+		g_warning ("Failed to connect to PipeWire");
+	return G_SOURCE_REMOVE;
+}
+
+int
+audiomixer_ensure_controls(struct audiomixer *self, int timeout_sec)
+{
+	gint64 end_time = g_get_monotonic_time () + timeout_sec * G_TIME_SPAN_SECOND;
+
+	g_return_val_if_fail (self->initialized == 1, -EIO);
+
+	if (!wp_core_is_connected (self->core))
+		g_main_context_invoke (self->context, (GSourceFunc) do_connect, self->core);
+
+	while (self->mixer_controls->len == 0) {
+		if (!g_cond_wait_until (&self->cond, &self->lock, end_time))
+			return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+const struct mixer_control **
+audiomixer_get_active_controls(struct audiomixer *self,
+	unsigned int *n_controls)
+{
+	*n_controls = self->mixer_controls->len;
+	return (const struct mixer_control **) self->mixer_controls->pdata;
+}
+
+const struct mixer_control *
+audiomixer_find_control(struct audiomixer *self, const char *name)
+{
+	struct mixer_control *ctl;
+
+	for (guint i = 0; i < self->mixer_controls->len; i++) {
+		ctl = g_ptr_array_index (self->mixer_controls, i);
+		if (!strcmp(ctl->name, name)) {
+			return ctl;
+		}
+	}
+	return NULL;
+}
+
+void
+audiomixer_add_event_listener(struct audiomixer *self,
+	const struct audiomixer_events *events,
+	void *data)
+{
+	self->events = events;
+	self->events_data = data;
+}
+
+static gboolean
+do_change_volume (struct action * action)
+{
+	struct audiomixer *self = action->audiomixer;
+	GVariantBuilder b = G_VARIANT_BUILDER_INIT (G_VARIANT_TYPE_VARDICT);
+	gboolean ret = FALSE;
+
+	g_variant_builder_add (&b, "{sv}", "volume",
+		g_variant_new_double (action->change_volume.volume));
+	g_signal_emit_by_name (self->mixer_api, "set-volume",
+		action->change_volume.id, g_variant_builder_end (&b), &ret);
+	if (!ret)
+		g_warning ("mixer api set-volume failed");
+
+	return G_SOURCE_REMOVE;
+}
+
+void
+audiomixer_change_volume(struct audiomixer *self,
+	const struct mixer_control *control,
+	double volume)
+{
+	const struct mixer_control_impl *impl =
+		(const struct mixer_control_impl *) control;
+	struct action * action;
+
+	g_return_if_fail (self->initialized == 1);
+
+	/* schedule the action to run on the audiomixer thread */
+	action = g_new0 (struct action, 1);
+	action->audiomixer = self;
+	action->change_volume.id = impl->node_id;
+	action->change_volume.volume = (gfloat) volume;
+	wp_core_idle_add (self->core, NULL, (GSourceFunc) do_change_volume, action,
+		g_free);
+}
+
+static gboolean
+do_change_mute (struct action * action)
+{
+	struct audiomixer *self = action->audiomixer;
+	GVariantBuilder b = G_VARIANT_BUILDER_INIT (G_VARIANT_TYPE_VARDICT);
+	gboolean ret = FALSE;
+
+	g_variant_builder_add (&b, "{sv}", "mute",
+		g_variant_new_boolean (action->change_mute.mute));
+	g_signal_emit_by_name (self->mixer_api, "set-volume",
+		action->change_mute.id, g_variant_builder_end (&b), &ret);
+	if (!ret)
+		g_warning ("mixer api set-volume failed");
+
+	return G_SOURCE_REMOVE;
+}
+
+void
+audiomixer_change_mute(struct audiomixer *self,
+	const struct mixer_control *control,
+	bool mute)
+{
+	const struct mixer_control_impl *impl =
+		(const struct mixer_control_impl *) control;
+	struct action * action;
+
+	g_return_if_fail (self->initialized == 1);
+
+	/* schedule the action to run on the audiomixer thread */
+	action = g_new0 (struct action, 1);
+	action->audiomixer = self;
+	action->change_mute.id = impl->node_id;
+	action->change_mute.mute = mute;
+	wp_core_idle_add (self->core, NULL, (GSourceFunc) do_change_mute, action,
+		g_free);
+}