pipewire-pulse: add module-switch-on-connect

module-switch-on-connect sets the configured default sink/source
whenever suitable new sink/sources appear.

This should give the same behavior as Pulseaudio's module.

This module exists mainly to provide a workaround e.g. for desktop
environments such as XFCE, whose mixer applications try to manage the
default devices assuming fully PA-like behavior, breaking default
pipewire output switching.

src/modules/meson.build

@@ -194,6 +194,7 @@ pipewire_module_protocol_pulse_sources = [
   'module-protocol-pulse/modules/module-remap-sink.c',
   'module-protocol-pulse/modules/module-remap-source.c',
   'module-protocol-pulse/modules/module-simple-protocol-tcp.c',
+  'module-protocol-pulse/modules/module-switch-on-connect.c',
   'module-protocol-pulse/modules/module-tunnel-sink.c',
   'module-protocol-pulse/modules/module-tunnel-source.c',
   'module-protocol-pulse/modules/module-zeroconf-discover.c',

src/modules/module-protocol-pulse/module.c

@@ -242,6 +242,7 @@ static const struct module_info module_list[] = {
 	{ "module-remap-sink", create_module_remap_sink, },
 	{ "module-remap-source", create_module_remap_source, },
 	{ "module-simple-protocol-tcp", create_module_simple_protocol_tcp, },
+	{ "module-switch-on-connect", create_module_switch_on_connect, },
 	{ "module-tunnel-sink", create_module_tunnel_sink, },
 	{ "module-tunnel-source", create_module_tunnel_source, },
 	{ "module-zeroconf-discover", create_module_zeroconf_discover, },

src/modules/module-protocol-pulse/modules/module-switch-on-connect.c

@@ -0,0 +1,327 @@
+/* PipeWire
+ *
+ * Copyright © 2021 Wim Taymans <wim.taymans@gmail.com>
+ * Copyright © 2021 Pauli Virtanen <pav@iki.fi>
+ *
+ * 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/utils/hook.h>
+#include <spa/utils/json.h>
+#include <spa/utils/string.h>
+
+#include <regex.h>
+
+#include "../defs.h"
+#include "../module.h"
+#include "registry.h"
+
+#include "../manager.h"
+#include "../collect.h"
+
+#define NAME "pulse-server: module-switch-on-connect"
+
+/* Ignore HDMI by default */
+#define DEFAULT_BLOCKLIST "hdmi"
+
+struct module_switch_on_connect_data {
+	struct module *module;
+
+	struct pw_core *core;
+	struct pw_manager *manager;
+	struct spa_hook core_listener;
+	struct spa_hook manager_listener;
+	struct pw_manager_object *metadata_default;
+
+	regex_t *blocklist;
+
+	int sync_seq;
+
+	unsigned int only_from_unavailable:1;
+	unsigned int ignore_virtual:1;
+	unsigned int started:1;
+};
+
+static void handle_metadata(struct module_switch_on_connect_data *d, struct pw_manager_object *old,
+		struct pw_manager_object *new, const char *name)
+{
+	if (spa_streq(name, "default")) {
+		if (d->metadata_default == old)
+			d->metadata_default = new;
+	}
+}
+
+static void manager_added(void *data, struct pw_manager_object *o)
+{
+	struct module_switch_on_connect_data *d = data;
+	struct pw_node_info *info = o->info;
+	struct pw_device_info *card_info = NULL;
+	uint32_t card_id = SPA_ID_INVALID;
+	struct pw_manager_object *card = NULL;
+	const char *str, *bus, *name;
+
+	if (spa_streq(o->type, PW_TYPE_INTERFACE_Metadata)) {
+		if (o->props != NULL &&
+		    (str = pw_properties_get(o->props, PW_KEY_METADATA_NAME)) != NULL)
+			handle_metadata(d, NULL, o, str);
+	}
+
+	if (!d->metadata_default || !d->started)
+		return;
+
+	if (!(pw_manager_object_is_sink(o) || pw_manager_object_is_source_or_monitor(o)))
+		return;
+
+	if (!info || !info->props)
+		return;
+
+	name = spa_dict_lookup(info->props, PW_KEY_NODE_NAME);
+	if (!name)
+		return;
+
+	/* Find card */
+	if ((str = spa_dict_lookup(info->props, PW_KEY_DEVICE_ID)) != NULL)
+		card_id = (uint32_t)atoi(str);
+	if (card_id != SPA_ID_INVALID) {
+		struct selector sel = { .id = card_id, .type = pw_manager_object_is_card, };
+		card = select_object(d->manager, &sel);
+	}
+	if (!card)
+		return;
+	card_info = card->info;
+	if (!card_info || !card_info->props)
+		return;
+
+	pw_log_debug(NAME ": considering switching to %s", name);
+
+	/* If internal device, only consider hdmi sinks */
+	str = spa_dict_lookup(info->props, "api.alsa.path");
+	bus = spa_dict_lookup(card_info->props, PW_KEY_DEVICE_BUS);
+	if ((spa_streq(bus, "pci") || spa_streq(bus, "isa")) &&
+			!(pw_manager_object_is_sink(o) && spa_strstartswith(str, "hdmi"))) {
+		pw_log_debug(NAME ": not switching to internal device");
+		return;
+	}
+
+	if (d->blocklist && regexec(d->blocklist, name, 0, NULL, 0) == 0) {
+		pw_log_debug(NAME ": not switching to blocklisted device");
+		return;
+	}
+
+	if (d->ignore_virtual && spa_dict_lookup(info->props, PW_KEY_DEVICE_API) == NULL) {
+		pw_log_debug(NAME ": not switching to virtual device");
+		return;
+	}
+
+	if (d->only_from_unavailable) {
+		/* XXX: not implemented */
+	}
+
+	/* Switch default */
+	pw_log_debug(NAME ": switching to %s", name);
+
+	pw_manager_set_metadata(d->manager, d->metadata_default,
+			PW_ID_CORE,
+			pw_manager_object_is_sink(o) ? METADATA_CONFIG_DEFAULT_SINK
+				: METADATA_CONFIG_DEFAULT_SOURCE,
+			"Spa:String:JSON", "{ \"name\": \"%s\" }", name);
+}
+
+static void manager_sync(void *data)
+{
+	struct module_switch_on_connect_data *d = data;
+
+	/* Manager emits devices/etc next --- enable started flag after that */
+	if (!d->started)
+		d->sync_seq = pw_core_sync(d->core, PW_ID_CORE, d->sync_seq);
+}
+
+static const struct pw_manager_events manager_events = {
+	PW_VERSION_MANAGER_EVENTS,
+	.added = manager_added,
+	.sync = manager_sync,
+};
+
+static void on_core_done(void *data, uint32_t id, int seq)
+{
+	struct module_switch_on_connect_data *d = data;
+	if (seq == d->sync_seq) {
+		pw_log_debug(NAME" %p: started", d);
+		d->started = true;
+	}
+}
+
+static const struct pw_core_events core_events = {
+	PW_VERSION_CORE_EVENTS,
+	.done = on_core_done,
+};
+
+static int module_switch_on_connect_load(struct client *client, struct module *module)
+{
+	struct impl *impl = client->impl;
+	struct module_switch_on_connect_data *d = module->user_data;
+	int res;
+
+	d->core = pw_context_connect(impl->context, pw_properties_copy(client->props), 0);
+	if (d->core == NULL) {
+		res = -errno;
+		goto error;
+	}
+
+	d->manager = pw_manager_new(d->core);
+	if (d->manager == NULL) {
+		res = -errno;
+		pw_core_disconnect(d->core);
+		d->core = NULL;
+		goto error;
+	}
+
+	pw_manager_add_listener(d->manager, &d->manager_listener, &manager_events, d);
+	pw_core_add_listener(d->core, &d->core_listener, &core_events, d);
+
+	/* Postpone setting started flag after initial nodes emitted */
+	pw_manager_sync(d->manager);
+
+	return 0;
+
+error:
+	pw_log_error(NAME" %p: failed to connect: %s", impl, spa_strerror(res));
+	return res;
+}
+
+static int module_switch_on_connect_unload(struct client *client, struct module *module)
+{
+	struct module_switch_on_connect_data *d = module->user_data;
+
+	if (d->manager) {
+		spa_hook_remove(&d->manager_listener);
+		pw_manager_destroy(d->manager);
+		d->manager = NULL;
+	}
+
+	if (d->core) {
+		spa_hook_remove(&d->core_listener);
+		pw_core_disconnect(d->core);
+		d->core = NULL;
+	}
+
+	if (d->blocklist) {
+		regfree(d->blocklist);
+		free(d->blocklist);
+		d->blocklist = NULL;
+	}
+
+	return 0;
+}
+
+static const struct module_methods module_switch_on_connect_methods = {
+	VERSION_MODULE_METHODS,
+	.load = module_switch_on_connect_load,
+	.unload = module_switch_on_connect_unload,
+};
+
+static const struct spa_dict_item module_switch_on_connect_info[] = {
+	{ PW_KEY_MODULE_AUTHOR, "Pauli Virtanen <pav@iki.fi>" },
+	{ PW_KEY_MODULE_DESCRIPTION, "Switch to new devices on connect. "
+	  "This module exists for Pulseaudio compatibility, and is useful only when some applications "
+	  "try to manage the default sinks/sources themselves and interfere with PipeWire's builtin "
+	  "default device switching." },
+	{ PW_KEY_MODULE_USAGE, "only_from_unavailable=<boolean, only switch from unavailable ports (not implemented yet)> "
+				"ignore_virtual=<boolean, ignore new virtual sinks and sources, defaults to true> "
+				"blocklist=<regex, ignore matching devices, default=hdmi> " },
+	{ PW_KEY_MODULE_VERSION, PACKAGE_VERSION },
+};
+
+struct module *create_module_switch_on_connect(struct impl *impl, const char *argument)
+{
+	struct module *module;
+	struct module_switch_on_connect_data *d;
+	struct pw_properties *props = NULL;
+	regex_t *blocklist = NULL;
+	bool only_from_unavailable = false, ignore_virtual = true;
+	const char *str;
+	int res;
+
+	props = pw_properties_new_dict(&SPA_DICT_INIT_ARRAY(module_switch_on_connect_info));
+	if (!props) {
+		res = -EINVAL;
+		goto out;
+	}
+	if (argument)
+		module_args_add_props(props, argument);
+
+	if ((str = pw_properties_get(props, "only_from_unavailable")) != NULL) {
+		only_from_unavailable = pw_properties_parse_bool(str);
+		pw_properties_set(props, "only_from_unavailable", NULL);
+	}
+
+	if ((str = pw_properties_get(props, "ignore_virtual")) != NULL) {
+		ignore_virtual = pw_properties_parse_bool(str);
+		pw_properties_set(props, "ignore_virtual", NULL);
+	}
+
+	if ((blocklist = malloc(sizeof(regex_t))) == NULL) {
+		res = -ENOMEM;
+		goto out;
+	}
+
+	if ((str = pw_properties_get(props, "blocklist")) == NULL)
+		str = DEFAULT_BLOCKLIST;
+
+	if ((res = regcomp(blocklist, str, REG_NOSUB | REG_EXTENDED)) != 0) {
+		free(blocklist);
+		blocklist = NULL;
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (str != DEFAULT_BLOCKLIST)
+		pw_properties_set(props, "blocklist", NULL);
+
+	module = module_new(impl, &module_switch_on_connect_methods, sizeof(*d));
+	if (module == NULL) {
+		res = -errno;
+		goto out;
+	}
+
+	module->props = props;
+	d = module->user_data;
+	d->module = module;
+	d->blocklist = blocklist;
+	d->ignore_virtual = ignore_virtual;
+	d->only_from_unavailable = only_from_unavailable;
+
+	if (d->only_from_unavailable) {
+		/* XXX: not implemented */
+		pw_log_warn(NAME": only_from_unavailable is not implemented");
+	}
+
+	return module;
+
+out:
+	pw_properties_free(props);
+	if (blocklist) {
+		regfree(blocklist);
+		free(blocklist);
+	}
+	errno = -res;
+
+	return NULL;
+}

src/modules/module-protocol-pulse/modules/registry.h

@@ -40,6 +40,7 @@ struct module *create_module_remap_source(struct impl *impl, const char *argumen
 struct module *create_module_tunnel_sink(struct impl *impl, const char *argument);
 struct module *create_module_tunnel_source(struct impl *impl, const char *argument);
 struct module *create_module_simple_protocol_tcp(struct impl *impl, const char *argument);
+struct module *create_module_switch_on_connect(struct impl *impl, const char *argument);
 struct module *create_module_pipe_source(struct impl *impl, const char *argument);
 struct module *create_module_pipe_sink(struct impl *impl, const char *argument);
 struct module *create_module_zeroconf_discover(struct impl *impl, const char *argument);