session-manager: implement factories for session, endpoint-stream & endpoint-link

Heavily based on the endpoint factory

src/modules/meson.build

@@ -145,9 +145,12 @@ pipewire_module_session_manager = shared_library('pipewire-module-session-manage
     'module-session-manager/client-session/client-session.c',
     'module-session-manager/client-session/endpoint-link.c',
     'module-session-manager/client-session/session.c',
+    'module-session-manager/endpoint-link.c',
+    'module-session-manager/endpoint-stream.c',
     'module-session-manager/endpoint.c',
     'module-session-manager/protocol-native.c',
     'module-session-manager/proxy-session-manager.c',
+    'module-session-manager/session.c',
   ],
   c_args : pipewire_module_c_args,
   include_directories : [configinc, spa_inc],

src/modules/module-session-manager.c

@@ -32,7 +32,10 @@ int client_endpoint_factory_init(struct pw_impl_module *module);
 /* client-session.c */
 int client_session_factory_init(struct pw_impl_module *module);
 
+int session_factory_init(struct pw_impl_module *module);
 int endpoint_factory_init(struct pw_impl_module *module);
+int endpoint_stream_factory_init(struct pw_impl_module *module);
+int endpoint_link_factory_init(struct pw_impl_module *module);
 
 /* protocol-native.c */
 int pw_protocol_native_ext_session_manager_init(struct pw_context *context);
@@ -54,7 +57,10 @@ int pipewire__module_init(struct pw_impl_module *module, const char *args)
 
 	client_endpoint_factory_init(module);
 	client_session_factory_init(module);
+	session_factory_init(module);
 	endpoint_factory_init(module);
+	endpoint_stream_factory_init(module);
+	endpoint_link_factory_init(module);
 
 	pw_impl_module_update_properties(module, &SPA_DICT_INIT_ARRAY(module_props));
 

src/modules/module-session-manager/endpoint-link.c

@@ -0,0 +1,549 @@
+/* PipeWire
+ *
+ * Copyright © 2020 Collabora Ltd.
+ *   @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * 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 <pipewire/impl.h>
+#include <extensions/session-manager.h>
+#include <extensions/session-manager/introspect-funcs.h>
+
+#include <spa/utils/result.h>
+#include <spa/pod/builder.h>
+#include <spa/pod/filter.h>
+
+#define MAX_PARAMS 32
+
+#define NAME "endpoint-link"
+
+struct pw_proxy *pw_core_endpoint_link_export(struct pw_core *core,
+		const char *type, const struct spa_dict *props, void *object,
+		size_t user_data_size);
+
+struct impl
+{
+	struct pw_global *global;
+	struct spa_hook global_listener;
+
+	union {
+		struct pw_endpoint_link *link;
+		struct pw_resource *resource;
+	};
+	struct spa_hook resource_listener;
+	struct spa_hook link_listener;
+
+	struct pw_endpoint_link_info *cached_info;
+	struct spa_list cached_params;
+
+	int ping_seq;
+	bool registered;
+};
+
+struct param_data
+{
+	struct spa_list link;
+	uint32_t id;
+	struct pw_array params;
+};
+
+struct resource_data
+{
+	struct impl *impl;
+
+	struct pw_resource *resource;
+	struct spa_hook object_listener;
+
+	uint32_t n_subscribe_ids;
+	uint32_t subscribe_ids[32];
+};
+
+struct factory_data
+{
+	struct pw_impl_factory *this;
+
+	struct pw_impl_module *module;
+	struct spa_hook module_listener;
+
+	struct pw_export_type export;
+};
+
+#define pw_endpoint_link_resource(r,m,v,...)      \
+	pw_resource_call(r,struct pw_endpoint_link_events,m,v,__VA_ARGS__)
+
+#define pw_endpoint_link_resource_info(r,...)        \
+        pw_endpoint_link_resource(r,info,0,__VA_ARGS__)
+#define pw_endpoint_link_resource_param(r,...)        \
+        pw_endpoint_link_resource(r,param,0,__VA_ARGS__)
+
+static int method_enum_params(void *object, int seq,
+			uint32_t id, uint32_t start, uint32_t num,
+			const struct spa_pod *filter)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	struct param_data *pdata;
+	struct spa_pod *result;
+	struct spa_pod *param;
+	uint8_t buffer[1024];
+	struct spa_pod_builder b = { 0 };
+	uint32_t index;
+	uint32_t next = start;
+	uint32_t count = 0;
+
+	pw_log_debug(NAME" %p: param %u %d/%d", impl, id, start, num);
+
+	spa_list_for_each(pdata, &impl->cached_params, link) {
+		if (pdata->id != id)
+			continue;
+
+		while (true) {
+			index = next++;
+			if (index >= pw_array_get_len(&pdata->params, void*))
+				return 0;
+
+			param = *pw_array_get_unchecked(&pdata->params, index, struct spa_pod*);
+
+			spa_pod_builder_init(&b, buffer, sizeof(buffer));
+			if (spa_pod_filter(&b, &result, param, filter) != 0)
+				continue;
+
+			pw_log_debug(NAME" %p: %d param %u", impl, seq, index);
+
+			pw_endpoint_link_resource_param(d->resource, seq, id, index, next, result);
+
+			if (++count == num)
+				return 0;
+		}
+	}
+
+	return 0;
+}
+
+static int method_subscribe_params(void *object, uint32_t *ids, uint32_t n_ids)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	uint32_t i;
+
+	n_ids = SPA_MIN(n_ids, SPA_N_ELEMENTS(d->subscribe_ids));
+	d->n_subscribe_ids = n_ids;
+
+	for (i = 0; i < n_ids; i++) {
+		d->subscribe_ids[i] = ids[i];
+		pw_log_debug(NAME" %p: resource %d subscribe param %u",
+			impl, pw_resource_get_id(d->resource), ids[i]);
+		method_enum_params(object, 1, ids[i], 0, UINT32_MAX, NULL);
+	}
+	return 0;
+}
+
+static int method_set_param(void *object, uint32_t id, uint32_t flags,
+			  const struct spa_pod *param)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	/* store only on the implementation; our cache will be updated
+	   by the param event, since we are subscribed */
+	pw_endpoint_link_set_param(impl->link, id, flags, param);
+	return 0;
+}
+
+static int method_request_state(void *object, enum pw_endpoint_link_state state)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	pw_endpoint_link_request_state(impl->link, state);
+	return 0;
+}
+
+static const struct pw_endpoint_link_methods link_methods = {
+	PW_VERSION_ENDPOINT_LINK_METHODS,
+	.subscribe_params = method_subscribe_params,
+	.enum_params = method_enum_params,
+	.set_param = method_set_param,
+	.request_state = method_request_state,
+};
+
+static int global_bind(void *_data, struct pw_impl_client *client,
+		uint32_t permissions, uint32_t version, uint32_t id)
+{
+	struct impl *impl = _data;
+	struct pw_resource *resource;
+	struct resource_data *data;
+
+	resource = pw_resource_new(client, id, permissions,
+				PW_TYPE_INTERFACE_EndpointLink,
+				version, sizeof(*data));
+	if (resource == NULL)
+		return -errno;
+
+	data = pw_resource_get_user_data(resource);
+	data->impl = impl;
+	data->resource = resource;
+
+	pw_global_add_resource(impl->global, resource);
+
+	/* resource methods -> implemention */
+	pw_resource_add_object_listener(resource,
+			&data->object_listener,
+			&link_methods, data);
+
+	pw_endpoint_link_resource_info(resource, impl->cached_info);
+
+	return 0;
+}
+
+static void global_destroy(void *data)
+{
+	struct impl *impl = data;
+	spa_hook_remove(&impl->global_listener);
+	impl->global = NULL;
+	if (impl->resource)
+		pw_resource_destroy(impl->resource);
+}
+
+static const struct pw_global_events global_events = {
+	PW_VERSION_GLOBAL_EVENTS,
+	.destroy = global_destroy,
+};
+
+static void impl_resource_destroy(void *data)
+{
+	struct impl *impl = data;
+	struct param_data *pdata, *tmp;
+
+	spa_hook_remove(&impl->resource_listener);
+	impl->resource = NULL;
+
+	/* clear cache */
+	if (impl->cached_info)
+		pw_endpoint_link_info_free(impl->cached_info);
+	spa_list_for_each_safe(pdata, tmp, &impl->cached_params, link) {
+		struct spa_pod **pod;
+		pw_array_for_each(pod, &pdata->params)
+			free(*pod);
+		pw_array_clear(&pdata->params);
+		spa_list_remove(&pdata->link);
+		free(pdata);
+	}
+
+	if (impl->global)
+		pw_global_destroy(impl->global);
+}
+
+static void register_global(struct impl *impl)
+{
+	impl->cached_info->id = pw_global_get_id (impl->global);
+	pw_resource_set_bound_id(impl->resource, impl->cached_info->id);
+	pw_global_register(impl->global);
+	impl->registered = true;
+}
+
+static void impl_resource_pong (void *data, int seq)
+{
+	struct impl *impl = data;
+
+	/* complete registration, if this was the initial sync */
+	if (!impl->registered && seq == impl->ping_seq) {
+		register_global(impl);
+	}
+}
+
+static const struct pw_resource_events impl_resource_events = {
+	PW_VERSION_RESOURCE_EVENTS,
+	.destroy = impl_resource_destroy,
+	.pong = impl_resource_pong,
+};
+
+static int emit_info(void *data, struct pw_resource *resource)
+{
+	const struct pw_endpoint_link_info *info = data;
+	pw_endpoint_link_resource_info(resource, info);
+	return 0;
+}
+
+static void event_info(void *object, const struct pw_endpoint_link_info *info)
+{
+	struct impl *impl = object;
+	uint32_t changed_ids[MAX_PARAMS], n_changed_ids = 0;
+	uint32_t i;
+
+	/* figure out changes to params */
+	if (info->change_mask & PW_ENDPOINT_LINK_CHANGE_MASK_PARAMS) {
+		for (i = 0; i < info->n_params; i++) {
+			if ((!impl->cached_info ||
+				info->params[i].flags != impl->cached_info->params[i].flags)
+			    && info->params[i].flags & SPA_PARAM_INFO_READ)
+				changed_ids[n_changed_ids++] = info->params[i].id;
+		}
+	}
+
+	/* cache for new clients */
+	impl->cached_info = pw_endpoint_link_info_update (impl->cached_info, info);
+
+	/* notify existing clients */
+	pw_global_for_each_resource(impl->global, emit_info, (void*) info);
+
+	/* cache params & register */
+	if (n_changed_ids > 0) {
+		/* prepare params storage */
+		for (i = 0; i < n_changed_ids; i++) {
+			struct param_data *pdata = calloc(1, sizeof(struct param_data));
+			pdata->id = changed_ids[i];
+			pw_array_init(&pdata->params, sizeof(void*));
+			spa_list_append(&impl->cached_params, &pdata->link);
+		}
+
+		/* subscribe to impl */
+		pw_endpoint_link_subscribe_params(impl->link, changed_ids, n_changed_ids);
+
+		/* register asynchronously on the pong event */
+		impl->ping_seq = pw_resource_ping(impl->resource, 0);
+	}
+	else if (!impl->registered) {
+		register_global(impl);
+	}
+}
+
+struct param_event_args
+{
+	uint32_t id, index, next;
+	const struct spa_pod *param;
+};
+
+static int emit_param(void *_data, struct pw_resource *resource)
+{
+	struct param_event_args *args = _data;
+	struct resource_data *data;
+	uint32_t i;
+
+	data = pw_resource_get_user_data(resource);
+	for (i = 0; i < data->n_subscribe_ids; i++) {
+		if (data->subscribe_ids[i] == args->id) {
+			pw_endpoint_link_resource_param(resource, 1,
+				args->id, args->index, args->next, args->param);
+		}
+	}
+	return 0;
+}
+
+static void event_param(void *object, int seq,
+		       uint32_t id, uint32_t index, uint32_t next,
+		       const struct spa_pod *param)
+{
+	struct impl *impl = object;
+	struct param_data *pdata;
+	struct spa_pod **pod;
+	struct param_event_args args = { id, index, next, param };
+
+	/* cache for new requests */
+	spa_list_for_each(pdata, &impl->cached_params, link) {
+		if (pdata->id != id)
+			continue;
+
+		if (!pw_array_check_index(&pdata->params, index, void*)) {
+			while (pw_array_get_len(&pdata->params, void*) <= index)
+				pw_array_add_ptr(&pdata->params, NULL);
+		}
+
+		pod = pw_array_get_unchecked(&pdata->params, index, struct spa_pod*);
+		free(*pod);
+		*pod = spa_pod_copy(param);
+	}
+
+	/* notify existing clients */
+	pw_global_for_each_resource(impl->global, emit_param, &args);
+}
+
+static const struct pw_endpoint_link_events link_events = {
+	PW_VERSION_ENDPOINT_LINK_EVENTS,
+	.info = event_info,
+	.param = event_param,
+};
+
+static void *link_new(struct pw_context *context,
+			  struct pw_resource *resource,
+			  struct pw_properties *properties)
+{
+	struct impl *impl;
+
+	impl = calloc(1, sizeof(*impl));
+	if (impl == NULL) {
+		pw_properties_free(properties);
+		return NULL;
+	}
+
+	impl->global = pw_global_new(context,
+			PW_TYPE_INTERFACE_EndpointLink,
+			PW_VERSION_ENDPOINT_LINK,
+			properties,
+			global_bind, impl);
+	if (impl->global == NULL) {
+		free(impl);
+		return NULL;
+	}
+	impl->resource = resource;
+
+	spa_list_init(&impl->cached_params);
+
+	/* handle destroy events */
+	pw_global_add_listener(impl->global,
+			&impl->global_listener,
+			&global_events, impl);
+	pw_resource_add_listener(impl->resource,
+			&impl->resource_listener,
+			&impl_resource_events, impl);
+
+	/* handle implementation events -> cache + client resources */
+	pw_endpoint_link_add_listener(impl->link,
+			&impl->link_listener,
+			&link_events, impl);
+
+	/* global is not registered here on purpose;
+	   we first cache info + params and then expose the global */
+
+	return impl;
+}
+
+static void *create_object(void *data,
+			   struct pw_resource *resource,
+			   const char *type,
+			   uint32_t version,
+			   struct pw_properties *properties,
+			   uint32_t new_id)
+{
+	struct factory_data *d = data;
+	struct pw_resource *impl_resource;
+	struct pw_impl_client *client = pw_resource_get_client(resource);
+	void *result;
+	int res;
+
+	impl_resource = pw_resource_new(client, new_id, PW_PERM_RWX, type, version, 0);
+	if (impl_resource == NULL) {
+		res = -errno;
+		goto error_resource;
+	}
+
+	pw_resource_install_marshal(impl_resource, true);
+
+	if (properties == NULL)
+		properties = pw_properties_new(NULL, NULL);
+	if (properties == NULL) {
+		res = -ENOMEM;
+		goto error_link;
+	}
+
+	pw_properties_setf(properties, PW_KEY_CLIENT_ID, "%d",
+			pw_impl_client_get_info(client)->id);
+	pw_properties_setf(properties, PW_KEY_FACTORY_ID, "%d",
+			pw_impl_factory_get_info(d->this)->id);
+
+	result = link_new(pw_impl_client_get_context(client), impl_resource, properties);
+	if (result == NULL) {
+		res = -errno;
+		goto error_link;
+	}
+	return result;
+
+error_resource:
+	pw_log_error("can't create resource: %s", spa_strerror(res));
+	pw_resource_errorf_id(resource, new_id, res, "can't create resource: %s", spa_strerror(res));
+	goto error_exit;
+error_link:
+	pw_log_error("can't create endpoint link: %s", spa_strerror(res));
+	pw_resource_errorf_id(resource, new_id, res, "can't create endpoint link: %s", spa_strerror(res));
+	goto error_exit_free;
+
+error_exit_free:
+	pw_resource_remove(impl_resource);
+error_exit:
+	errno = -res;
+	return NULL;
+}
+
+static const struct pw_impl_factory_implementation impl_factory = {
+	PW_VERSION_IMPL_FACTORY_IMPLEMENTATION,
+	.create_object = create_object,
+};
+
+static void module_destroy(void *data)
+{
+	struct factory_data *d = data;
+
+	spa_hook_remove(&d->module_listener);
+	spa_list_remove(&d->export.link);
+	pw_impl_factory_destroy(d->this);
+}
+
+static void module_registered(void *data)
+{
+	struct factory_data *d = data;
+	struct pw_impl_module *module = d->module;
+	struct pw_impl_factory *factory = d->this;
+	struct spa_dict_item items[1];
+	char id[16];
+	int res;
+
+	snprintf(id, sizeof(id), "%d", pw_impl_module_get_info(module)->id);
+	items[0] = SPA_DICT_ITEM_INIT(PW_KEY_MODULE_ID, id);
+	pw_impl_factory_update_properties(factory, &SPA_DICT_INIT(items, 1));
+
+	if ((res = pw_impl_factory_register(factory, NULL)) < 0) {
+		pw_log_error(NAME" %p: can't register factory: %s", factory, spa_strerror(res));
+	}
+}
+
+static const struct pw_impl_module_events module_events = {
+	PW_VERSION_IMPL_MODULE_EVENTS,
+	.destroy = module_destroy,
+	.registered = module_registered,
+};
+
+int endpoint_link_factory_init(struct pw_impl_module *module)
+{
+	struct pw_context *context = pw_impl_module_get_context(module);
+	struct pw_impl_factory *factory;
+	struct factory_data *data;
+
+	factory = pw_context_create_factory(context,
+				 "endpoint-link",
+				 PW_TYPE_INTERFACE_EndpointLink,
+				 PW_VERSION_ENDPOINT_LINK,
+				 NULL,
+				 sizeof(*data));
+	if (factory == NULL)
+		return -errno;
+
+	data = pw_impl_factory_get_user_data(factory);
+	data->this = factory;
+	data->module = module;
+
+	pw_impl_factory_set_implementation(factory, &impl_factory, data);
+
+	data->export.type = PW_TYPE_INTERFACE_EndpointLink;
+	data->export.func = pw_core_endpoint_link_export;
+	pw_context_register_export_type(context, &data->export);
+
+	pw_impl_module_add_listener(module, &data->module_listener, &module_events, data);
+
+	return 0;
+}

src/modules/module-session-manager/endpoint-stream.c

@@ -0,0 +1,540 @@
+/* PipeWire
+ *
+ * Copyright © 2020 Collabora Ltd.
+ *   @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * 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 <pipewire/impl.h>
+#include <extensions/session-manager.h>
+#include <extensions/session-manager/introspect-funcs.h>
+
+#include <spa/utils/result.h>
+#include <spa/pod/builder.h>
+#include <spa/pod/filter.h>
+
+#define MAX_PARAMS 32
+
+#define NAME "endpoint-stream"
+
+struct pw_proxy *pw_core_endpoint_stream_export(struct pw_core *core,
+		const char *type, const struct spa_dict *props, void *object,
+		size_t user_data_size);
+
+struct impl
+{
+	struct pw_global *global;
+	struct spa_hook global_listener;
+
+	union {
+		struct pw_endpoint_stream *stream;
+		struct pw_resource *resource;
+	};
+	struct spa_hook resource_listener;
+	struct spa_hook stream_listener;
+
+	struct pw_endpoint_stream_info *cached_info;
+	struct spa_list cached_params;
+
+	int ping_seq;
+	bool registered;
+};
+
+struct param_data
+{
+	struct spa_list link;
+	uint32_t id;
+	struct pw_array params;
+};
+
+struct resource_data
+{
+	struct impl *impl;
+
+	struct pw_resource *resource;
+	struct spa_hook object_listener;
+
+	uint32_t n_subscribe_ids;
+	uint32_t subscribe_ids[32];
+};
+
+struct factory_data
+{
+	struct pw_impl_factory *this;
+
+	struct pw_impl_module *module;
+	struct spa_hook module_listener;
+
+	struct pw_export_type export;
+};
+
+#define pw_endpoint_stream_resource(r,m,v,...)      \
+	pw_resource_call(r,struct pw_endpoint_stream_events,m,v,__VA_ARGS__)
+
+#define pw_endpoint_stream_resource_info(r,...)        \
+        pw_endpoint_stream_resource(r,info,0,__VA_ARGS__)
+#define pw_endpoint_stream_resource_param(r,...)        \
+        pw_endpoint_stream_resource(r,param,0,__VA_ARGS__)
+
+static int method_enum_params(void *object, int seq,
+			uint32_t id, uint32_t start, uint32_t num,
+			const struct spa_pod *filter)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	struct param_data *pdata;
+	struct spa_pod *result;
+	struct spa_pod *param;
+	uint8_t buffer[1024];
+	struct spa_pod_builder b = { 0 };
+	uint32_t index;
+	uint32_t next = start;
+	uint32_t count = 0;
+
+	pw_log_debug(NAME" %p: param %u %d/%d", impl, id, start, num);
+
+	spa_list_for_each(pdata, &impl->cached_params, link) {
+		if (pdata->id != id)
+			continue;
+
+		while (true) {
+			index = next++;
+			if (index >= pw_array_get_len(&pdata->params, void*))
+				return 0;
+
+			param = *pw_array_get_unchecked(&pdata->params, index, struct spa_pod*);
+
+			spa_pod_builder_init(&b, buffer, sizeof(buffer));
+			if (spa_pod_filter(&b, &result, param, filter) != 0)
+				continue;
+
+			pw_log_debug(NAME" %p: %d param %u", impl, seq, index);
+
+			pw_endpoint_stream_resource_param(d->resource, seq, id, index, next, result);
+
+			if (++count == num)
+				return 0;
+		}
+	}
+
+	return 0;
+}
+
+static int method_subscribe_params(void *object, uint32_t *ids, uint32_t n_ids)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	uint32_t i;
+
+	n_ids = SPA_MIN(n_ids, SPA_N_ELEMENTS(d->subscribe_ids));
+	d->n_subscribe_ids = n_ids;
+
+	for (i = 0; i < n_ids; i++) {
+		d->subscribe_ids[i] = ids[i];
+		pw_log_debug(NAME" %p: resource %d subscribe param %u",
+			impl, pw_resource_get_id(d->resource), ids[i]);
+		method_enum_params(object, 1, ids[i], 0, UINT32_MAX, NULL);
+	}
+	return 0;
+}
+
+static int method_set_param(void *object, uint32_t id, uint32_t flags,
+			  const struct spa_pod *param)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	/* store only on the implementation; our cache will be updated
+	   by the param event, since we are subscribed */
+	pw_endpoint_stream_set_param(impl->stream, id, flags, param);
+	return 0;
+}
+
+static const struct pw_endpoint_stream_methods stream_methods = {
+	PW_VERSION_ENDPOINT_STREAM_METHODS,
+	.subscribe_params = method_subscribe_params,
+	.enum_params = method_enum_params,
+	.set_param = method_set_param,
+};
+
+static int global_bind(void *_data, struct pw_impl_client *client,
+		uint32_t permissions, uint32_t version, uint32_t id)
+{
+	struct impl *impl = _data;
+	struct pw_resource *resource;
+	struct resource_data *data;
+
+	resource = pw_resource_new(client, id, permissions,
+				PW_TYPE_INTERFACE_EndpointStream,
+				version, sizeof(*data));
+	if (resource == NULL)
+		return -errno;
+
+	data = pw_resource_get_user_data(resource);
+	data->impl = impl;
+	data->resource = resource;
+
+	pw_global_add_resource(impl->global, resource);
+
+	/* resource methods -> implemention */
+	pw_resource_add_object_listener(resource,
+			&data->object_listener,
+			&stream_methods, data);
+
+	pw_endpoint_stream_resource_info(resource, impl->cached_info);
+
+	return 0;
+}
+
+static void global_destroy(void *data)
+{
+	struct impl *impl = data;
+	spa_hook_remove(&impl->global_listener);
+	impl->global = NULL;
+	if (impl->resource)
+		pw_resource_destroy(impl->resource);
+}
+
+static const struct pw_global_events global_events = {
+	PW_VERSION_GLOBAL_EVENTS,
+	.destroy = global_destroy,
+};
+
+static void impl_resource_destroy(void *data)
+{
+	struct impl *impl = data;
+	struct param_data *pdata, *tmp;
+
+	spa_hook_remove(&impl->resource_listener);
+	impl->resource = NULL;
+
+	/* clear cache */
+	if (impl->cached_info)
+		pw_endpoint_stream_info_free(impl->cached_info);
+	spa_list_for_each_safe(pdata, tmp, &impl->cached_params, link) {
+		struct spa_pod **pod;
+		pw_array_for_each(pod, &pdata->params)
+			free(*pod);
+		pw_array_clear(&pdata->params);
+		spa_list_remove(&pdata->link);
+		free(pdata);
+	}
+
+	if (impl->global)
+		pw_global_destroy(impl->global);
+}
+
+static void register_global(struct impl *impl)
+{
+	impl->cached_info->id = pw_global_get_id (impl->global);
+	pw_resource_set_bound_id(impl->resource, impl->cached_info->id);
+	pw_global_register(impl->global);
+	impl->registered = true;
+}
+
+static void impl_resource_pong (void *data, int seq)
+{
+	struct impl *impl = data;
+
+	/* complete registration, if this was the initial sync */
+	if (!impl->registered && seq == impl->ping_seq) {
+		register_global(impl);
+	}
+}
+
+static const struct pw_resource_events impl_resource_events = {
+	PW_VERSION_RESOURCE_EVENTS,
+	.destroy = impl_resource_destroy,
+	.pong = impl_resource_pong,
+};
+
+static int emit_info(void *data, struct pw_resource *resource)
+{
+	const struct pw_endpoint_stream_info *info = data;
+	pw_endpoint_stream_resource_info(resource, info);
+	return 0;
+}
+
+static void event_info(void *object, const struct pw_endpoint_stream_info *info)
+{
+	struct impl *impl = object;
+	uint32_t changed_ids[MAX_PARAMS], n_changed_ids = 0;
+	uint32_t i;
+
+	/* figure out changes to params */
+	if (info->change_mask & PW_ENDPOINT_STREAM_CHANGE_MASK_PARAMS) {
+		for (i = 0; i < info->n_params; i++) {
+			if ((!impl->cached_info ||
+				info->params[i].flags != impl->cached_info->params[i].flags)
+			    && info->params[i].flags & SPA_PARAM_INFO_READ)
+				changed_ids[n_changed_ids++] = info->params[i].id;
+		}
+	}
+
+	/* cache for new clients */
+	impl->cached_info = pw_endpoint_stream_info_update (impl->cached_info, info);
+
+	/* notify existing clients */
+	pw_global_for_each_resource(impl->global, emit_info, (void*) info);
+
+	/* cache params & register */
+	if (n_changed_ids > 0) {
+		/* prepare params storage */
+		for (i = 0; i < n_changed_ids; i++) {
+			struct param_data *pdata = calloc(1, sizeof(struct param_data));
+			pdata->id = changed_ids[i];
+			pw_array_init(&pdata->params, sizeof(void*));
+			spa_list_append(&impl->cached_params, &pdata->link);
+		}
+
+		/* subscribe to impl */
+		pw_endpoint_stream_subscribe_params(impl->stream, changed_ids, n_changed_ids);
+
+		/* register asynchronously on the pong event */
+		impl->ping_seq = pw_resource_ping(impl->resource, 0);
+	}
+	else if (!impl->registered) {
+		register_global(impl);
+	}
+}
+
+struct param_event_args
+{
+	uint32_t id, index, next;
+	const struct spa_pod *param;
+};
+
+static int emit_param(void *_data, struct pw_resource *resource)
+{
+	struct param_event_args *args = _data;
+	struct resource_data *data;
+	uint32_t i;
+
+	data = pw_resource_get_user_data(resource);
+	for (i = 0; i < data->n_subscribe_ids; i++) {
+		if (data->subscribe_ids[i] == args->id) {
+			pw_endpoint_stream_resource_param(resource, 1,
+				args->id, args->index, args->next, args->param);
+		}
+	}
+	return 0;
+}
+
+static void event_param(void *object, int seq,
+		       uint32_t id, uint32_t index, uint32_t next,
+		       const struct spa_pod *param)
+{
+	struct impl *impl = object;
+	struct param_data *pdata;
+	struct spa_pod **pod;
+	struct param_event_args args = { id, index, next, param };
+
+	/* cache for new requests */
+	spa_list_for_each(pdata, &impl->cached_params, link) {
+		if (pdata->id != id)
+			continue;
+
+		if (!pw_array_check_index(&pdata->params, index, void*)) {
+			while (pw_array_get_len(&pdata->params, void*) <= index)
+				pw_array_add_ptr(&pdata->params, NULL);
+		}
+
+		pod = pw_array_get_unchecked(&pdata->params, index, struct spa_pod*);
+		free(*pod);
+		*pod = spa_pod_copy(param);
+	}
+
+	/* notify existing clients */
+	pw_global_for_each_resource(impl->global, emit_param, &args);
+}
+
+static const struct pw_endpoint_stream_events stream_events = {
+	PW_VERSION_ENDPOINT_STREAM_EVENTS,
+	.info = event_info,
+	.param = event_param,
+};
+
+static void *stream_new(struct pw_context *context,
+			  struct pw_resource *resource,
+			  struct pw_properties *properties)
+{
+	struct impl *impl;
+
+	impl = calloc(1, sizeof(*impl));
+	if (impl == NULL) {
+		pw_properties_free(properties);
+		return NULL;
+	}
+
+	impl->global = pw_global_new(context,
+			PW_TYPE_INTERFACE_EndpointStream,
+			PW_VERSION_ENDPOINT_STREAM,
+			properties,
+			global_bind, impl);
+	if (impl->global == NULL) {
+		free(impl);
+		return NULL;
+	}
+	impl->resource = resource;
+
+	spa_list_init(&impl->cached_params);
+
+	/* handle destroy events */
+	pw_global_add_listener(impl->global,
+			&impl->global_listener,
+			&global_events, impl);
+	pw_resource_add_listener(impl->resource,
+			&impl->resource_listener,
+			&impl_resource_events, impl);
+
+	/* handle implementation events -> cache + client resources */
+	pw_endpoint_stream_add_listener(impl->stream,
+			&impl->stream_listener,
+			&stream_events, impl);
+
+	/* global is not registered here on purpose;
+	   we first cache info + params and then expose the global */
+
+	return impl;
+}
+
+static void *create_object(void *data,
+			   struct pw_resource *resource,
+			   const char *type,
+			   uint32_t version,
+			   struct pw_properties *properties,
+			   uint32_t new_id)
+{
+	struct factory_data *d = data;
+	struct pw_resource *impl_resource;
+	struct pw_impl_client *client = pw_resource_get_client(resource);
+	void *result;
+	int res;
+
+	impl_resource = pw_resource_new(client, new_id, PW_PERM_RWX, type, version, 0);
+	if (impl_resource == NULL) {
+		res = -errno;
+		goto error_resource;
+	}
+
+	pw_resource_install_marshal(impl_resource, true);
+
+	if (properties == NULL)
+		properties = pw_properties_new(NULL, NULL);
+	if (properties == NULL) {
+		res = -ENOMEM;
+		goto error_stream;
+	}
+
+	pw_properties_setf(properties, PW_KEY_CLIENT_ID, "%d",
+			pw_impl_client_get_info(client)->id);
+	pw_properties_setf(properties, PW_KEY_FACTORY_ID, "%d",
+			pw_impl_factory_get_info(d->this)->id);
+
+	result = stream_new(pw_impl_client_get_context(client), impl_resource, properties);
+	if (result == NULL) {
+		res = -errno;
+		goto error_stream;
+	}
+	return result;
+
+error_resource:
+	pw_log_error("can't create resource: %s", spa_strerror(res));
+	pw_resource_errorf_id(resource, new_id, res, "can't create resource: %s", spa_strerror(res));
+	goto error_exit;
+error_stream:
+	pw_log_error("can't create endpoint stream: %s", spa_strerror(res));
+	pw_resource_errorf_id(resource, new_id, res, "can't create endpoint stream: %s", spa_strerror(res));
+	goto error_exit_free;
+
+error_exit_free:
+	pw_resource_remove(impl_resource);
+error_exit:
+	errno = -res;
+	return NULL;
+}
+
+static const struct pw_impl_factory_implementation impl_factory = {
+	PW_VERSION_IMPL_FACTORY_IMPLEMENTATION,
+	.create_object = create_object,
+};
+
+static void module_destroy(void *data)
+{
+	struct factory_data *d = data;
+
+	spa_hook_remove(&d->module_listener);
+	spa_list_remove(&d->export.link);
+	pw_impl_factory_destroy(d->this);
+}
+
+static void module_registered(void *data)
+{
+	struct factory_data *d = data;
+	struct pw_impl_module *module = d->module;
+	struct pw_impl_factory *factory = d->this;
+	struct spa_dict_item items[1];
+	char id[16];
+	int res;
+
+	snprintf(id, sizeof(id), "%d", pw_impl_module_get_info(module)->id);
+	items[0] = SPA_DICT_ITEM_INIT(PW_KEY_MODULE_ID, id);
+	pw_impl_factory_update_properties(factory, &SPA_DICT_INIT(items, 1));
+
+	if ((res = pw_impl_factory_register(factory, NULL)) < 0) {
+		pw_log_error(NAME" %p: can't register factory: %s", factory, spa_strerror(res));
+	}
+}
+
+static const struct pw_impl_module_events module_events = {
+	PW_VERSION_IMPL_MODULE_EVENTS,
+	.destroy = module_destroy,
+	.registered = module_registered,
+};
+
+int endpoint_stream_factory_init(struct pw_impl_module *module)
+{
+	struct pw_context *context = pw_impl_module_get_context(module);
+	struct pw_impl_factory *factory;
+	struct factory_data *data;
+
+	factory = pw_context_create_factory(context,
+				 "endpoint-stream",
+				 PW_TYPE_INTERFACE_EndpointStream,
+				 PW_VERSION_ENDPOINT_STREAM,
+				 NULL,
+				 sizeof(*data));
+	if (factory == NULL)
+		return -errno;
+
+	data = pw_impl_factory_get_user_data(factory);
+	data->this = factory;
+	data->module = module;
+
+	pw_impl_factory_set_implementation(factory, &impl_factory, data);
+
+	data->export.type = PW_TYPE_INTERFACE_EndpointStream;
+	data->export.func = pw_core_endpoint_stream_export;
+	pw_context_register_export_type(context, &data->export);
+
+	pw_impl_module_add_listener(module, &data->module_listener, &module_events, data);
+
+	return 0;
+}

src/modules/module-session-manager/session.c

@@ -0,0 +1,540 @@
+/* PipeWire
+ *
+ * Copyright © 2020 Collabora Ltd.
+ *   @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * 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 <pipewire/impl.h>
+#include <extensions/session-manager.h>
+#include <extensions/session-manager/introspect-funcs.h>
+
+#include <spa/utils/result.h>
+#include <spa/pod/builder.h>
+#include <spa/pod/filter.h>
+
+#define MAX_PARAMS 32
+
+#define NAME "session"
+
+struct pw_proxy *pw_core_session_export(struct pw_core *core,
+		const char *type, const struct spa_dict *props, void *object,
+		size_t user_data_size);
+
+struct impl
+{
+	struct pw_global *global;
+	struct spa_hook global_listener;
+
+	union {
+		struct pw_session *session;
+		struct pw_resource *resource;
+	};
+	struct spa_hook resource_listener;
+	struct spa_hook session_listener;
+
+	struct pw_session_info *cached_info;
+	struct spa_list cached_params;
+
+	int ping_seq;
+	bool registered;
+};
+
+struct param_data
+{
+	struct spa_list link;
+	uint32_t id;
+	struct pw_array params;
+};
+
+struct resource_data
+{
+	struct impl *impl;
+
+	struct pw_resource *resource;
+	struct spa_hook object_listener;
+
+	uint32_t n_subscribe_ids;
+	uint32_t subscribe_ids[32];
+};
+
+struct factory_data
+{
+	struct pw_impl_factory *this;
+
+	struct pw_impl_module *module;
+	struct spa_hook module_listener;
+
+	struct pw_export_type export;
+};
+
+#define pw_session_resource(r,m,v,...)      \
+	pw_resource_call(r,struct pw_session_events,m,v,__VA_ARGS__)
+
+#define pw_session_resource_info(r,...)        \
+        pw_session_resource(r,info,0,__VA_ARGS__)
+#define pw_session_resource_param(r,...)        \
+        pw_session_resource(r,param,0,__VA_ARGS__)
+
+static int method_enum_params(void *object, int seq,
+			uint32_t id, uint32_t start, uint32_t num,
+			const struct spa_pod *filter)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	struct param_data *pdata;
+	struct spa_pod *result;
+	struct spa_pod *param;
+	uint8_t buffer[1024];
+	struct spa_pod_builder b = { 0 };
+	uint32_t index;
+	uint32_t next = start;
+	uint32_t count = 0;
+
+	pw_log_debug(NAME" %p: param %u %d/%d", impl, id, start, num);
+
+	spa_list_for_each(pdata, &impl->cached_params, link) {
+		if (pdata->id != id)
+			continue;
+
+		while (true) {
+			index = next++;
+			if (index >= pw_array_get_len(&pdata->params, void*))
+				return 0;
+
+			param = *pw_array_get_unchecked(&pdata->params, index, struct spa_pod*);
+
+			spa_pod_builder_init(&b, buffer, sizeof(buffer));
+			if (spa_pod_filter(&b, &result, param, filter) != 0)
+				continue;
+
+			pw_log_debug(NAME" %p: %d param %u", impl, seq, index);
+
+			pw_session_resource_param(d->resource, seq, id, index, next, result);
+
+			if (++count == num)
+				return 0;
+		}
+	}
+
+	return 0;
+}
+
+static int method_subscribe_params(void *object, uint32_t *ids, uint32_t n_ids)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	uint32_t i;
+
+	n_ids = SPA_MIN(n_ids, SPA_N_ELEMENTS(d->subscribe_ids));
+	d->n_subscribe_ids = n_ids;
+
+	for (i = 0; i < n_ids; i++) {
+		d->subscribe_ids[i] = ids[i];
+		pw_log_debug(NAME" %p: resource %d subscribe param %u",
+			impl, pw_resource_get_id(d->resource), ids[i]);
+		method_enum_params(object, 1, ids[i], 0, UINT32_MAX, NULL);
+	}
+	return 0;
+}
+
+static int method_set_param(void *object, uint32_t id, uint32_t flags,
+			  const struct spa_pod *param)
+{
+	struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	/* store only on the implementation; our cache will be updated
+	   by the param event, since we are subscribed */
+	pw_session_set_param(impl->session, id, flags, param);
+	return 0;
+}
+
+static const struct pw_session_methods session_methods = {
+	PW_VERSION_SESSION_METHODS,
+	.subscribe_params = method_subscribe_params,
+	.enum_params = method_enum_params,
+	.set_param = method_set_param,
+};
+
+static int global_bind(void *_data, struct pw_impl_client *client,
+		uint32_t permissions, uint32_t version, uint32_t id)
+{
+	struct impl *impl = _data;
+	struct pw_resource *resource;
+	struct resource_data *data;
+
+	resource = pw_resource_new(client, id, permissions,
+				PW_TYPE_INTERFACE_Session,
+				version, sizeof(*data));
+	if (resource == NULL)
+		return -errno;
+
+	data = pw_resource_get_user_data(resource);
+	data->impl = impl;
+	data->resource = resource;
+
+	pw_global_add_resource(impl->global, resource);
+
+	/* resource methods -> implemention */
+	pw_resource_add_object_listener(resource,
+			&data->object_listener,
+			&session_methods, data);
+
+	pw_session_resource_info(resource, impl->cached_info);
+
+	return 0;
+}
+
+static void global_destroy(void *data)
+{
+	struct impl *impl = data;
+	spa_hook_remove(&impl->global_listener);
+	impl->global = NULL;
+	if (impl->resource)
+		pw_resource_destroy(impl->resource);
+}
+
+static const struct pw_global_events global_events = {
+	PW_VERSION_GLOBAL_EVENTS,
+	.destroy = global_destroy,
+};
+
+static void impl_resource_destroy(void *data)
+{
+	struct impl *impl = data;
+	struct param_data *pdata, *tmp;
+
+	spa_hook_remove(&impl->resource_listener);
+	impl->resource = NULL;
+
+	/* clear cache */
+	if (impl->cached_info)
+		pw_session_info_free(impl->cached_info);
+	spa_list_for_each_safe(pdata, tmp, &impl->cached_params, link) {
+		struct spa_pod **pod;
+		pw_array_for_each(pod, &pdata->params)
+			free(*pod);
+		pw_array_clear(&pdata->params);
+		spa_list_remove(&pdata->link);
+		free(pdata);
+	}
+
+	if (impl->global)
+		pw_global_destroy(impl->global);
+}
+
+static void register_global(struct impl *impl)
+{
+	impl->cached_info->id = pw_global_get_id (impl->global);
+	pw_resource_set_bound_id(impl->resource, impl->cached_info->id);
+	pw_global_register(impl->global);
+	impl->registered = true;
+}
+
+static void impl_resource_pong (void *data, int seq)
+{
+	struct impl *impl = data;
+
+	/* complete registration, if this was the initial sync */
+	if (!impl->registered && seq == impl->ping_seq) {
+		register_global(impl);
+	}
+}
+
+static const struct pw_resource_events impl_resource_events = {
+	PW_VERSION_RESOURCE_EVENTS,
+	.destroy = impl_resource_destroy,
+	.pong = impl_resource_pong,
+};
+
+static int emit_info(void *data, struct pw_resource *resource)
+{
+	const struct pw_session_info *info = data;
+	pw_session_resource_info(resource, info);
+	return 0;
+}
+
+static void event_info(void *object, const struct pw_session_info *info)
+{
+	struct impl *impl = object;
+	uint32_t changed_ids[MAX_PARAMS], n_changed_ids = 0;
+	uint32_t i;
+
+	/* figure out changes to params */
+	if (info->change_mask & PW_SESSION_CHANGE_MASK_PARAMS) {
+		for (i = 0; i < info->n_params; i++) {
+			if ((!impl->cached_info ||
+				info->params[i].flags != impl->cached_info->params[i].flags)
+			    && info->params[i].flags & SPA_PARAM_INFO_READ)
+				changed_ids[n_changed_ids++] = info->params[i].id;
+		}
+	}
+
+	/* cache for new clients */
+	impl->cached_info = pw_session_info_update (impl->cached_info, info);
+
+	/* notify existing clients */
+	pw_global_for_each_resource(impl->global, emit_info, (void*) info);
+
+	/* cache params & register */
+	if (n_changed_ids > 0) {
+		/* prepare params storage */
+		for (i = 0; i < n_changed_ids; i++) {
+			struct param_data *pdata = calloc(1, sizeof(struct param_data));
+			pdata->id = changed_ids[i];
+			pw_array_init(&pdata->params, sizeof(void*));
+			spa_list_append(&impl->cached_params, &pdata->link);
+		}
+
+		/* subscribe to impl */
+		pw_session_subscribe_params(impl->session, changed_ids, n_changed_ids);
+
+		/* register asynchronously on the pong event */
+		impl->ping_seq = pw_resource_ping(impl->resource, 0);
+	}
+	else if (!impl->registered) {
+		register_global(impl);
+	}
+}
+
+struct param_event_args
+{
+	uint32_t id, index, next;
+	const struct spa_pod *param;
+};
+
+static int emit_param(void *_data, struct pw_resource *resource)
+{
+	struct param_event_args *args = _data;
+	struct resource_data *data;
+	uint32_t i;
+
+	data = pw_resource_get_user_data(resource);
+	for (i = 0; i < data->n_subscribe_ids; i++) {
+		if (data->subscribe_ids[i] == args->id) {
+			pw_session_resource_param(resource, 1,
+				args->id, args->index, args->next, args->param);
+		}
+	}
+	return 0;
+}
+
+static void event_param(void *object, int seq,
+		       uint32_t id, uint32_t index, uint32_t next,
+		       const struct spa_pod *param)
+{
+	struct impl *impl = object;
+	struct param_data *pdata;
+	struct spa_pod **pod;
+	struct param_event_args args = { id, index, next, param };
+
+	/* cache for new requests */
+	spa_list_for_each(pdata, &impl->cached_params, link) {
+		if (pdata->id != id)
+			continue;
+
+		if (!pw_array_check_index(&pdata->params, index, void*)) {
+			while (pw_array_get_len(&pdata->params, void*) <= index)
+				pw_array_add_ptr(&pdata->params, NULL);
+		}
+
+		pod = pw_array_get_unchecked(&pdata->params, index, struct spa_pod*);
+		free(*pod);
+		*pod = spa_pod_copy(param);
+	}
+
+	/* notify existing clients */
+	pw_global_for_each_resource(impl->global, emit_param, &args);
+}
+
+static const struct pw_session_events session_events = {
+	PW_VERSION_SESSION_EVENTS,
+	.info = event_info,
+	.param = event_param,
+};
+
+static void *session_new(struct pw_context *context,
+			  struct pw_resource *resource,
+			  struct pw_properties *properties)
+{
+	struct impl *impl;
+
+	impl = calloc(1, sizeof(*impl));
+	if (impl == NULL) {
+		pw_properties_free(properties);
+		return NULL;
+	}
+
+	impl->global = pw_global_new(context,
+			PW_TYPE_INTERFACE_Session,
+			PW_VERSION_SESSION,
+			properties,
+			global_bind, impl);
+	if (impl->global == NULL) {
+		free(impl);
+		return NULL;
+	}
+	impl->resource = resource;
+
+	spa_list_init(&impl->cached_params);
+
+	/* handle destroy events */
+	pw_global_add_listener(impl->global,
+			&impl->global_listener,
+			&global_events, impl);
+	pw_resource_add_listener(impl->resource,
+			&impl->resource_listener,
+			&impl_resource_events, impl);
+
+	/* handle implementation events -> cache + client resources */
+	pw_session_add_listener(impl->session,
+			&impl->session_listener,
+			&session_events, impl);
+
+	/* global is not registered here on purpose;
+	   we first cache info + params and then expose the global */
+
+	return impl;
+}
+
+static void *create_object(void *data,
+			   struct pw_resource *resource,
+			   const char *type,
+			   uint32_t version,
+			   struct pw_properties *properties,
+			   uint32_t new_id)
+{
+	struct factory_data *d = data;
+	struct pw_resource *impl_resource;
+	struct pw_impl_client *client = pw_resource_get_client(resource);
+	void *result;
+	int res;
+
+	impl_resource = pw_resource_new(client, new_id, PW_PERM_RWX, type, version, 0);
+	if (impl_resource == NULL) {
+		res = -errno;
+		goto error_resource;
+	}
+
+	pw_resource_install_marshal(impl_resource, true);
+
+	if (properties == NULL)
+		properties = pw_properties_new(NULL, NULL);
+	if (properties == NULL) {
+		res = -ENOMEM;
+		goto error_session;
+	}
+
+	pw_properties_setf(properties, PW_KEY_CLIENT_ID, "%d",
+			pw_impl_client_get_info(client)->id);
+	pw_properties_setf(properties, PW_KEY_FACTORY_ID, "%d",
+			pw_impl_factory_get_info(d->this)->id);
+
+	result = session_new(pw_impl_client_get_context(client), impl_resource, properties);
+	if (result == NULL) {
+		res = -errno;
+		goto error_session;
+	}
+	return result;
+
+error_resource:
+	pw_log_error("can't create resource: %s", spa_strerror(res));
+	pw_resource_errorf_id(resource, new_id, res, "can't create resource: %s", spa_strerror(res));
+	goto error_exit;
+error_session:
+	pw_log_error("can't create session: %s", spa_strerror(res));
+	pw_resource_errorf_id(resource, new_id, res, "can't create session: %s", spa_strerror(res));
+	goto error_exit_free;
+
+error_exit_free:
+	pw_resource_remove(impl_resource);
+error_exit:
+	errno = -res;
+	return NULL;
+}
+
+static const struct pw_impl_factory_implementation impl_factory = {
+	PW_VERSION_IMPL_FACTORY_IMPLEMENTATION,
+	.create_object = create_object,
+};
+
+static void module_destroy(void *data)
+{
+	struct factory_data *d = data;
+
+	spa_hook_remove(&d->module_listener);
+	spa_list_remove(&d->export.link);
+	pw_impl_factory_destroy(d->this);
+}
+
+static void module_registered(void *data)
+{
+	struct factory_data *d = data;
+	struct pw_impl_module *module = d->module;
+	struct pw_impl_factory *factory = d->this;
+	struct spa_dict_item items[1];
+	char id[16];
+	int res;
+
+	snprintf(id, sizeof(id), "%d", pw_impl_module_get_info(module)->id);
+	items[0] = SPA_DICT_ITEM_INIT(PW_KEY_MODULE_ID, id);
+	pw_impl_factory_update_properties(factory, &SPA_DICT_INIT(items, 1));
+
+	if ((res = pw_impl_factory_register(factory, NULL)) < 0) {
+		pw_log_error(NAME" %p: can't register factory: %s", factory, spa_strerror(res));
+	}
+}
+
+static const struct pw_impl_module_events module_events = {
+	PW_VERSION_IMPL_MODULE_EVENTS,
+	.destroy = module_destroy,
+	.registered = module_registered,
+};
+
+int session_factory_init(struct pw_impl_module *module)
+{
+	struct pw_context *context = pw_impl_module_get_context(module);
+	struct pw_impl_factory *factory;
+	struct factory_data *data;
+
+	factory = pw_context_create_factory(context,
+				 "session",
+				 PW_TYPE_INTERFACE_Session,
+				 PW_VERSION_SESSION,
+				 NULL,
+				 sizeof(*data));
+	if (factory == NULL)
+		return -errno;
+
+	data = pw_impl_factory_get_user_data(factory);
+	data->this = factory;
+	data->module = module;
+
+	pw_impl_factory_set_implementation(factory, &impl_factory, data);
+
+	data->export.type = PW_TYPE_INTERFACE_Session;
+	data->export.func = pw_core_session_export;
+	pw_context_register_export_type(context, &data->export);
+
+	pw_impl_module_add_listener(module, &data->module_listener, &module_events, data);
+
+	return 0;
+}