metadata: Add metadata API

Metadata allows apps to attach properties to objects that can be
read by other apps.
Not complete yet, properties should be removed when the object is
removed.

src/modules/module-metadata/metadata.c

@@ -0,0 +1,186 @@
+/* PipeWire
+ *
+ * Copyright © 2019 Wim Taymans
+ *
+ * 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/pipewire.h>
+#include "pipewire/private.h"
+
+#include <extensions/metadata.h>
+
+struct impl {
+	struct pw_global *global;
+
+	struct pw_metadata *metadata;
+	struct pw_resource *resource;
+	struct spa_hook resource_listener;
+};
+
+struct resource_data {
+	struct impl *impl;
+
+	struct pw_resource *resource;
+	struct spa_hook resource_listener;
+	struct spa_hook object_listener;
+	struct spa_hook metadata_listener;
+};
+
+static int metadata_set_property(void *object,
+			uint32_t subject,
+			const char *key,
+			const char *type,
+			const char *value)
+{
+        struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	pw_log_debug("%p", impl->metadata);
+	pw_metadata_set_property(impl->metadata, subject, key, type, value);
+	return 0;
+}
+
+
+static int metadata_clear(void *object)
+{
+        struct resource_data *d = object;
+	struct impl *impl = d->impl;
+	pw_log_debug("%p", impl->metadata);
+	pw_metadata_clear(impl->metadata);
+	return 0;
+}
+
+static const struct pw_metadata_methods metadata_methods = {
+	PW_VERSION_METADATA_METHODS,
+	.set_property = metadata_set_property,
+	.clear = metadata_clear,
+};
+
+#define pw_metadata_resource(r,m,v,...)      \
+	pw_resource_call_res(r,struct pw_metadata_events,m,v,__VA_ARGS__)
+
+#define pw_metadata_resource_property(r,...)        \
+        pw_metadata_resource(r,property,0,__VA_ARGS__)
+
+static int metadata_property(void *object,
+			uint32_t subject,
+			const char *key,
+			const char *type,
+			const char *value)
+{
+        struct resource_data *d = object;
+	pw_log_debug("%p", d->resource);
+	pw_metadata_resource_property(d->resource, subject, key, type, value);
+	return 0;
+}
+
+static const struct pw_metadata_events metadata_events = {
+	PW_VERSION_METADATA_EVENTS,
+	.property = metadata_property,
+};
+
+static void global_unbind(void *data)
+{
+        struct resource_data *d = data;
+	if (d->resource)
+	        spa_hook_remove(&d->metadata_listener);
+}
+
+static const struct pw_resource_events resource_events = {
+	PW_VERSION_RESOURCE_EVENTS,
+	.destroy = global_unbind,
+};
+
+static int
+global_bind(void *_data, struct pw_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_Metadata, version, sizeof(*data));
+        if (resource == NULL)
+                return -errno;
+
+        data = pw_resource_get_user_data(resource);
+        data->impl = impl;
+        data->resource = resource;
+
+	pw_log_debug(".");
+//	pw_resource_install_marshal(resource, true);
+
+	/* listen for when the resource goes away */
+        pw_resource_add_listener(resource,
+                        &data->resource_listener,
+                        &resource_events, data);
+
+	/* resource methods -> implemention */
+	pw_log_debug(".");
+	pw_resource_add_object_listener(resource,
+			&data->object_listener,
+                        &metadata_methods, data);
+	/* implementation events -> resource */
+	pw_log_debug(". %p", impl->metadata);
+	pw_metadata_add_listener(impl->metadata,
+			&data->metadata_listener,
+			&metadata_events, data);
+	pw_log_debug(".");
+
+	return 0;
+}
+
+void *
+pw_metadata_new(struct pw_core *core, struct pw_resource *resource,
+		   struct pw_properties *properties)
+{
+	struct impl *impl;
+
+	if (properties == NULL)
+		properties = pw_properties_new(NULL, NULL);
+	if (properties == NULL)
+		return NULL;
+
+	impl = calloc(1, sizeof(*impl));
+	if (impl == NULL) {
+		pw_properties_free(properties);
+		return NULL;
+	}
+
+	pw_properties_set(properties, PW_KEY_METADATA_NAME, "default");
+
+	pw_resource_install_marshal(resource, true);
+
+	impl->global = pw_global_new(core,
+			PW_TYPE_INTERFACE_Metadata,
+			PW_VERSION_METADATA,
+			properties,
+			global_bind, impl);
+	if (impl->global == NULL) {
+		free(impl);
+		return NULL;
+	}
+	impl->resource = resource;
+	impl->metadata = (struct pw_metadata*)resource;
+
+	pw_global_register(impl->global);
+
+	return impl;
+}