settings: use metadata for settings

The settings metadata can be used to modify global context properties
at runtime such as min/max quantum, loglevel and samplerate.

See #1288

src/pipewire/context.c

@@ -385,6 +385,8 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 		goto error_free;
 	pw_log_info(NAME" %p: parsed %d context.exec items", this, res);
 
+	pw_settings_init(this);
+
 	pw_log_debug(NAME" %p: created", this);
 
 	return this;

src/pipewire/meson.build

@@ -73,6 +73,7 @@ pipewire_sources = [
   'protocol.c',
   'proxy.c',
   'resource.c',
+  'settings.c',
   'stream.c',
   'thread-loop.c',
   'utils.c',

src/pipewire/private.h

@@ -1241,6 +1241,8 @@ void pw_log_log_object(enum spa_log_level level, const char *file, int line,
 
 bool pw_log_is_default(void);
 
+int pw_settings_init(struct pw_context *context);
+
 /** \endcond */
 
 #ifdef __cplusplus

src/pipewire/settings.c

@@ -0,0 +1,146 @@
+/* PipeWire
+ *
+ * Copyright © 2021 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 "config.h"
+
+#include <spa/utils/result.h>
+#include <spa/utils/string.h>
+#include <spa/monitor/device.h>
+#include <spa/monitor/utils.h>
+#include <spa/pod/filter.h>
+
+#include <pipewire/impl.h>
+#include <pipewire/private.h>
+#include "pipewire/array.h"
+#include "pipewire/core.h"
+
+#include <extensions/metadata.h>
+
+#define NAME "settings"
+
+struct impl {
+	struct pw_context *context;
+	struct pw_impl_metadata *metadata;
+
+	struct spa_hook metadata_listener;
+};
+
+static void metadata_destroy(void *data)
+{
+	struct impl *impl = data;
+	spa_hook_remove(&impl->metadata_listener);
+	impl->metadata = NULL;
+}
+
+static int metadata_property(void *data, uint32_t subject, const char *key,
+		const char *type, const char *value)
+{
+	struct impl *impl = data;
+	struct pw_context *context = impl->context;
+	struct settings *d = &context->defaults;
+	struct settings *s = &context->settings;
+	uint32_t v;
+	bool recalc = false;
+
+	if (subject != PW_ID_CORE)
+		return 0;
+
+	if (spa_streq(key, "log.level")) {
+		v = value ? atoi(value) : 3;
+		pw_log_set_level(v);
+	} else if (spa_streq(key, "clock.min-quantum")) {
+		v = value ? atoi(value) : 0;
+		s->clock_min_quantum = v == 0 ? d->clock_min_quantum : v;
+		recalc = true;
+	} else if (spa_streq(key, "clock.max-quantum")) {
+		v = value ? atoi(value) : 0;
+		s->clock_max_quantum = v == 0 ? d->clock_max_quantum : v;
+		recalc = true;
+	} else if (spa_streq(key, "clock.force-rate")) {
+		v = value ? atoi(value) : 0;
+		s->clock_force_rate = v;
+		recalc = true;
+	} else if (spa_streq(key, "clock.force-quantum")) {
+		v = value ? atoi(value) : 0;
+		s->clock_force_quantum = SPA_MIN(v, 8192u);
+		recalc = true;
+	}
+	if (recalc)
+		pw_context_recalc_graph(context, "properties changed");
+
+	return 0;
+}
+
+static struct pw_impl_metadata_events metadata_events = {
+	PW_VERSION_IMPL_METADATA_EVENTS,
+	.destroy = metadata_destroy,
+	.property = metadata_property,
+};
+
+static void init_defaults(struct impl *impl)
+{
+	struct settings *s = &impl->context->settings;
+
+	pw_impl_metadata_set_propertyf(impl->metadata,
+			PW_ID_CORE, "log.level", "", "%d", s->log_level);
+	pw_impl_metadata_set_propertyf(impl->metadata,
+			PW_ID_CORE, "clock.min-quantum", "", "%d", s->clock_min_quantum);
+	pw_impl_metadata_set_propertyf(impl->metadata,
+			PW_ID_CORE, "clock.max-quantum", "", "%d", s->clock_max_quantum);
+	pw_impl_metadata_set_propertyf(impl->metadata,
+			PW_ID_CORE, "clock.force-quantum", "", "%d", s->clock_force_quantum);
+	pw_impl_metadata_set_propertyf(impl->metadata,
+			PW_ID_CORE, "clock.force-rate", "", "%d", s->clock_force_rate);
+}
+
+
+int pw_settings_init(struct pw_context *context)
+{
+	struct impl *impl;
+	int res;
+
+	impl = calloc(1, sizeof(*impl));
+	if (impl == NULL)
+		goto error_errno;
+
+	impl->context = context;
+	impl->metadata = pw_context_create_metadata(context, "settings", NULL, 0);
+
+	init_defaults(impl);
+
+	pw_impl_metadata_add_listener(impl->metadata,
+			&impl->metadata_listener,
+			&metadata_events, impl);
+
+	pw_impl_metadata_register(impl->metadata, NULL);
+
+	return 0;
+
+error_errno:
+	res = -errno;
+	goto error_free;
+error_free:
+	free(impl);
+	return res;
+}