1 files changed, 245 insertions, 0 deletions
diff --git a/src/modules/module-protocol-pulse/modules/module-loopback.c b/src/modules/module-protocol-pulse/modules/module-loopback.c
new file mode 100644
index 0000000..614ee50
--- /dev/null
+++ b/src/modules/module-protocol-pulse/modules/module-loopback.c
@@ -0,0 +1,245 @@
+/* PipeWire
+ *
+ * Copyright © 2021 Wim Taymans <wim.taymans@gmail.com>
+ * Copyright © 2021 Arun Raghavan <arun@asymptotic.io>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <spa/param/audio/format-utils.h>
+#include <spa/utils/hook.h>
+#include <spa/utils/json.h>
+#include <pipewire/pipewire.h>
+
+#include "../defs.h"
+#include "../module.h"
+
+#define NAME "loopback"
+
+PW_LOG_TOPIC_STATIC(mod_topic, "mod." NAME);
+#define PW_LOG_TOPIC_DEFAULT mod_topic
+
+struct module_loopback_data {
+	struct module *module;
+
+	struct pw_impl_module *mod;
+	struct spa_hook mod_listener;
+
+	struct pw_properties *capture_props;
+	struct pw_properties *playback_props;
+
+	struct spa_audio_info_raw info;
+	uint32_t latency_msec;
+};
+
+static void module_destroy(void *data)
+{
+	struct module_loopback_data *d = data;
+	spa_hook_remove(&d->mod_listener);
+	d->mod = NULL;
+	module_schedule_unload(d->module);
+}
+
+static const struct pw_impl_module_events module_events = {
+	PW_VERSION_IMPL_MODULE_EVENTS,
+	.destroy = module_destroy
+};
+
+static int module_loopback_load(struct module *module)
+{
+	struct module_loopback_data *data = module->user_data;
+	FILE *f;
+	char *args;
+	size_t size, i;
+	char val[256];
+
+	pw_properties_setf(data->capture_props, PW_KEY_NODE_GROUP, "loopback-%u", module->index);
+	pw_properties_setf(data->playback_props, PW_KEY_NODE_GROUP, "loopback-%u", module->index);
+	pw_properties_setf(data->capture_props, "pulse.module.id", "%u", module->index);
+	pw_properties_setf(data->playback_props, "pulse.module.id", "%u", module->index);
+
+	if ((f = open_memstream(&args, &size)) == NULL)
+		return -errno;
+
+	fprintf(f, "{");
+	if (data->info.channels != 0) {
+		fprintf(f, " audio.channels = %u", data->info.channels);
+		if (!(data->info.flags & SPA_AUDIO_FLAG_UNPOSITIONED)) {
+			fprintf(f, " audio.position = [ ");
+			for (i = 0; i < data->info.channels; i++)
+				fprintf(f, "%s%s", i == 0 ? "" : ",",
+					channel_id2name(data->info.position[i]));
+			fprintf(f, " ]");
+		}
+	}
+	if (data->latency_msec != 0)
+		fprintf(f, " target.delay.sec = %s",
+				spa_json_format_float(val, sizeof(val),
+					data->latency_msec / 1000.0f));
+	fprintf(f, " capture.props = {");
+	pw_properties_serialize_dict(f, &data->capture_props->dict, 0);
+	fprintf(f, " } playback.props = {");
+	pw_properties_serialize_dict(f, &data->playback_props->dict, 0);
+	fprintf(f, " } }");
+	fclose(f);
+
+	data->mod = pw_context_load_module(module->impl->context,
+			"libpipewire-module-loopback",
+			args, NULL);
+	free(args);
+
+	if (data->mod == NULL)
+		return -errno;
+
+	pw_impl_module_add_listener(data->mod,
+			&data->mod_listener,
+			&module_events, data);
+
+	return 0;
+}
+
+static int module_loopback_unload(struct module *module)
+{
+	struct module_loopback_data *d = module->user_data;
+
+	if (d->mod) {
+		spa_hook_remove(&d->mod_listener);
+		pw_impl_module_destroy(d->mod);
+		d->mod = NULL;
+	}
+
+	pw_properties_free(d->capture_props);
+	pw_properties_free(d->playback_props);
+
+	return 0;
+}
+
+static const struct spa_dict_item module_loopback_info[] = {
+	{ PW_KEY_MODULE_AUTHOR, "Arun Raghavan <arun@asymptotic.io>" },
+	{ PW_KEY_MODULE_DESCRIPTION, "Loopback from source to sink" },
+	{ PW_KEY_MODULE_USAGE, "source=<source to connect to> "
+				"sink=<sink to connect to> "
+				"latency_msec=<latency in ms> "
+				"rate=<sample rate> "
+				"channels=<number of channels> "
+				"channel_map=<channel map> "
+				"sink_input_properties=<proplist> "
+				"source_output_properties=<proplist> "
+				"source_dont_move=<boolean> "
+				"sink_dont_move=<boolean> "
+				"remix=<remix channels?> " },
+	{ PW_KEY_MODULE_VERSION, PACKAGE_VERSION },
+};
+
+static int module_loopback_prepare(struct module * const module)
+{
+	struct module_loopback_data * const d = module->user_data;
+	struct pw_properties * const props = module->props;
+	struct pw_properties *playback_props = NULL, *capture_props = NULL;
+	const char *str;
+	struct spa_audio_info_raw info = { 0 };
+	int res;
+
+	PW_LOG_TOPIC_INIT(mod_topic);
+
+	capture_props = pw_properties_new(NULL, NULL);
+	playback_props = pw_properties_new(NULL, NULL);
+	if (!capture_props || !playback_props) {
+		res = -EINVAL;
+		goto out;
+	}
+
+	/* The following modargs are not implemented:
+	 * adjust_time, max_latency_msec, fast_adjust_threshold_msec: these are just not relevant
+	 */
+
+	if ((str = pw_properties_get(props, "source")) != NULL) {
+		if (spa_strendswith(str, ".monitor")) {
+			pw_properties_setf(capture_props, PW_KEY_TARGET_OBJECT,
+					"%.*s", (int)strlen(str)-8, str);
+			pw_properties_set(capture_props, PW_KEY_STREAM_CAPTURE_SINK,
+					"true");
+		} else {
+			pw_properties_set(capture_props, PW_KEY_TARGET_OBJECT, str);
+		}
+		pw_properties_set(props, "source", NULL);
+	}
+
+	if ((str = pw_properties_get(props, "sink")) != NULL) {
+		pw_properties_set(playback_props, PW_KEY_TARGET_OBJECT, str);
+		pw_properties_set(props, "sink", NULL);
+	}
+
+	if (module_args_to_audioinfo(module->impl, props, &info) < 0) {
+		res = -EINVAL;
+		goto out;
+	}
+
+	if ((str = pw_properties_get(props, "source_dont_move")) != NULL) {
+		pw_properties_set(capture_props, PW_KEY_NODE_DONT_RECONNECT, str);
+		pw_properties_set(props, "source_dont_move", NULL);
+	}
+
+	if ((str = pw_properties_get(props, "sink_dont_move")) != NULL) {
+		pw_properties_set(playback_props, PW_KEY_NODE_DONT_RECONNECT, str);
+		pw_properties_set(props, "sink_dont_move", NULL);
+	}
+
+	if ((str = pw_properties_get(props, "remix")) != NULL) {
+		/* Note that the boolean is inverted */
+		pw_properties_set(playback_props, PW_KEY_STREAM_DONT_REMIX,
+				module_args_parse_bool(str) ? "false" : "true");
+		pw_properties_set(props, "remix", NULL);
+	}
+
+	if ((str = pw_properties_get(props, "latency_msec")) != NULL)
+		d->latency_msec = atoi(str);
+
+	if ((str = pw_properties_get(props, "sink_input_properties")) != NULL) {
+		module_args_add_props(playback_props, str);
+		pw_properties_set(props, "sink_input_properties", NULL);
+	}
+
+	if ((str = pw_properties_get(props, "source_output_properties")) != NULL) {
+		module_args_add_props(capture_props, str);
+		pw_properties_set(props, "source_output_properties", NULL);
+	}
+
+	d->module = module;
+	d->capture_props = capture_props;
+	d->playback_props = playback_props;
+	d->info = info;
+
+	return 0;
+out:
+	pw_properties_free(playback_props);
+	pw_properties_free(capture_props);
+
+	return res;
+}
+
+DEFINE_MODULE_INFO(module_loopback) = {
+	.name = "module-loopback",
+	.prepare = module_loopback_prepare,
+	.load = module_loopback_load,
+	.unload = module_loopback_unload,
+	.properties = &SPA_DICT_INIT_ARRAY(module_loopback_info),
+	.data_size = sizeof(struct module_loopback_data),
+};