lib: Introduce WpSettings API

- WpSettings is a singleton object which attaches itself to the core
  and registry, it provides a get_instance () for its clients.
- WpSettings provides API to get/set wireplumber settings and rules.
- main.c loads the new object and makes sure it is available for
  for all the modules and scripts. This is achieved by introducing
  a new activation step.
- Add the lua bindings for get_setting API.

lib/wp/meson.build

@@ -12,6 +12,7 @@ wp_lib_sources = files(
   'link.c',
   'log.c',
   'metadata.c',
+  'settings.c',
   'module.c',
   'node.c',
   'object.c',
@@ -51,6 +52,7 @@ wp_lib_headers = files(
   'link.h',
   'log.h',
   'metadata.h',
+  'settings.h',
   'module.h',
   'node.h',
   'object.h',

lib/wp/settings.c

@@ -0,0 +1,214 @@
+/* WirePlumber
+ *
+ * Copyright © 2022 Collabora Ltd.
+ *    @author Ashok Sidipotu <ashok.sidipotu@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define G_LOG_DOMAIN "wp-settings"
+
+#include <wp/wp.h>
+
+#include "settings.h"
+#include "metadata.h"
+#include "log.h"
+#include "private/registry.h"
+
+/*! \defgroup WpSettings */
+/*!
+ * \struct WpSettings
+ *
+ * WpSettings parses `sm-settings` metadata(contains wireplumber settings
+ * and rules), provides APIs to its clients(modules, lua scripts etc) to
+ * access and change them.
+ *
+ * Being a WpObject subclass, the settings inherits WpObject's activation
+ * system.
+ *
+ */
+
+struct _WpSettings
+{
+  WpObject parent;
+
+  GWeakRef core;
+
+  WpProperties *settings;
+  WpObjectManager *metadata_om;
+};
+
+G_DEFINE_TYPE (WpSettings, wp_settings, WP_TYPE_OBJECT)
+
+static void
+wp_settings_init (WpSettings * self)
+{
+}
+
+
+/*!
+ * \brief gets the value of a setting.
+ *
+ * \ingroup wpsetting
+ * \param self the handle
+ * \param setting name of the setting
+ * \returns (transfer none): boolean value of the string.
+ */
+gboolean wp_settings_get_boolean (WpSettings *self, const gchar *setting)
+{
+  g_return_val_if_fail (self, false);
+  g_return_val_if_fail (setting, false);
+
+  return spa_atob (wp_properties_get (self->settings, setting));
+}
+
+/*!
+ * \brief applies the rules and returns the applied props.
+ *
+ * This funtion applies the rules on the client properties and if
+ * there is a match, returns true and also copies the applied props.
+ *
+ * \ingroup wpsetting
+ * \param self the handle
+ * \param setting name of the setting
+ * \param rule name of the rule, this will match with the section mentioned
+ *  in the conf file.
+ * \param client_props client props array, these properties are inputs on which
+ *  the rules are applied.
+ * \param applied_props the resultant actions/properties as a result of the
+ *  application of rules are copied here.
+ * \returns TRUE if there is a match for the client_props and
+ * returns the applied props for the match.
+ */
+gboolean wp_settings_apply_rule (WpSettings *self, const gchar *rule,
+    WpProperties *client_props, WpProperties *applied_props)
+{
+  /* get the rule */
+  return true;
+}
+
+enum {
+  STEP_LOAD = WP_TRANSITION_STEP_CUSTOM_START,
+};
+
+static WpObjectFeatures
+wp_settings_get_supported_features (WpObject * self)
+{
+  return WP_SETTINGS_LOADED;
+}
+
+static guint
+wp_settings_activate_get_next_step (WpObject * object,
+    WpFeatureActivationTransition * transition, guint step,
+    WpObjectFeatures missing)
+{
+  g_return_val_if_fail (missing == WP_SETTINGS_LOADED,
+      WP_TRANSITION_STEP_ERROR);
+
+  return STEP_LOAD;
+}
+
+
+/*!
+ * \brief Returns the wpsettings instance that is associated with the
+ * given core.
+ *
+ * This method will also create the instance and register it with the core
+ * if it had not been created before.
+ *
+ * \param core the core
+ * \return (transfer full): the wpsettings instance
+ */
+WpSettings *
+wp_settings_get_instance (WpCore * core)
+{
+  WpRegistry *registry = wp_core_get_registry (core);
+  WpSettings *settings = wp_registry_find_object (registry,
+      (GEqualFunc) WP_IS_SETTINGS, NULL);
+
+  if (G_UNLIKELY (!settings)) {
+    settings = g_object_new (WP_TYPE_SETTINGS,
+        "core", core,
+        NULL);
+    g_weak_ref_set (&settings->core, core);
+
+    wp_registry_register_object (registry, g_object_ref (settings));
+  }
+
+  return settings;
+}
+
+static void
+on_metadata_added (WpObjectManager *om, WpMetadata *m, gpointer d)
+{
+  WpTransition * transition = WP_TRANSITION (d);
+  WpSettings * self = wp_transition_get_source_object (transition);
+  g_autoptr (WpIterator) it = wp_metadata_new_iterator (WP_METADATA (m), 0);
+  g_auto (GValue) val = G_VALUE_INIT;
+
+  for (; wp_iterator_next (it, &val); g_value_unset (&val)) {
+      const gchar *setting, *value;
+      wp_metadata_iterator_item_extract (&val, NULL, &setting, NULL, &value);
+      wp_properties_set (self->settings, setting, value);
+      wp_debug_object (self, "%s(%lu) = %s", setting, strlen(value), value);
+  }
+
+  wp_info_object (self, "loaded %d settings from metadata",
+      wp_properties_get_count (self->settings));
+
+  wp_object_update_features (WP_OBJECT (self), WP_SETTINGS_LOADED, 0);
+}
+
+static void
+wp_settings_activate_execute_step (WpObject * object,
+    WpFeatureActivationTransition * transition, guint step,
+    WpObjectFeatures missing)
+{
+  WpSettings * self = WP_SETTINGS (object);
+  g_autoptr (WpCore) core = wp_object_get_core (object);
+
+  switch (step) {
+  case STEP_LOAD: {
+
+    self->settings = wp_properties_new_empty ();
+
+    self->metadata_om = wp_object_manager_new ();
+    wp_object_manager_add_interest (self->metadata_om, WP_TYPE_METADATA,
+        WP_CONSTRAINT_TYPE_PW_GLOBAL_PROPERTY, "metadata.name", "=s",
+            "sm-settings", NULL);
+    wp_object_manager_request_object_features (self->metadata_om,
+        WP_TYPE_METADATA, WP_OBJECT_FEATURES_ALL);
+    g_signal_connect_object (self->metadata_om, "object-added",
+        G_CALLBACK (on_metadata_added), transition, 0);
+    wp_core_install_object_manager (core, self->metadata_om);
+
+    break;
+  }
+  case WP_TRANSITION_STEP_ERROR:
+    break;
+  default:
+    g_assert_not_reached ();
+  }
+}
+
+static void
+wp_settings_deactivate (WpObject * object, WpObjectFeatures features)
+{
+  WpSettings *self = WP_SETTINGS (object);
+
+  g_clear_pointer (&self->settings, wp_properties_unref);
+  g_clear_object (&self->metadata_om);
+
+  wp_object_update_features (WP_OBJECT (self), 0, WP_OBJECT_FEATURES_ALL);
+}
+
+static void
+wp_settings_class_init (WpSettingsClass * klass)
+{
+  WpObjectClass * wpobject_class = (WpObjectClass *) klass;
+
+  wpobject_class->activate_get_next_step = wp_settings_activate_get_next_step;
+  wpobject_class->activate_execute_step = wp_settings_activate_execute_step;
+  wpobject_class->deactivate = wp_settings_deactivate;
+  wpobject_class->get_supported_features = wp_settings_get_supported_features;
+}

lib/wp/settings.h

@@ -0,0 +1,47 @@
+/* WirePlumber
+ *
+ * Copyright © 2022 Collabora Ltd.
+ *    @author Ashok Sidipotu <ashok.sidipotu@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef __WIREPLUMBER_SETTINGS_H__
+#define __WIREPLUMBER_SETTINGS_H__
+
+#include "object.h"
+
+G_BEGIN_DECLS
+
+/*!
+ * \brief Flags to be used as WpObjectFeatures on WpSettings subclasses.
+ * \ingroup wpsettings
+ */
+typedef enum {
+  /* loads the metadata */
+  WP_SETTINGS_LOADED = (1 << 0),
+} WpSettingsFeatures;
+
+/*!
+ * \brief The WpSettings GType
+ * \ingroup wpsettings
+ */
+#define WP_TYPE_SETTINGS (wp_settings_get_type ())
+
+WP_API
+G_DECLARE_FINAL_TYPE (WpSettings, wp_settings, WP, SETTINGS, WpObject)
+
+WP_API
+WpSettings *
+wp_settings_get_instance (WpCore * core);
+
+WP_API
+gboolean wp_settings_get_boolean (WpSettings *self, const gchar *setting);
+
+WP_API
+gboolean wp_settings_apply_rule (WpSettings *self, const gchar *rule,
+    WpProperties *client_props, WpProperties *applied_props);
+
+G_END_DECLS
+
+#endif

lib/wp/transition.c

@@ -29,7 +29,7 @@
  * code must call wp_transition_return_error() instead, in which case the
  * transition completes immediately and wp_transition_had_error() returns TRUE.
  *
- * Typically, every step will start an asynchronous operation. Although is is
+ * Typically, every step will start an asynchronous operation. Although it is
  * possible, the WpTransition base class does not expect
  * _WpTransitionClass::execute_step() to call wp_transition_advance() directly.
  * Instead, it is expected that wp_transition_advance() will be called from

lib/wp/wp.h

@@ -42,6 +42,7 @@
 #include "wpenums.h"
 #include "wpversion.h"
 #include "factory.h"
+#include "settings.h"
 
 G_BEGIN_DECLS
 

modules/module-lua-scripting/api/api.c

@@ -1472,6 +1472,26 @@ impl_module_new (lua_State *L)
   }
 }
 
+static int
+get_setting (lua_State *L)
+{
+  const char *setting = luaL_checkstring (L, 1);
+  WpSettings *s = wp_settings_get_instance (get_wp_core (L));
+  if (s)
+  {
+    gboolean value = wp_settings_get_boolean (s, setting);
+    lua_pushboolean (L, value);
+  }
+  else
+    lua_pushnil (L);
+  return 1;
+}
+
+static const luaL_Reg settings_methods[] = {
+  { "get_setting", get_setting },
+  { NULL, NULL }
+};
+
 void
 wp_lua_scripting_api_init (lua_State *L)
 {
@@ -1492,6 +1512,9 @@ wp_lua_scripting_api_init (lua_State *L)
   luaL_newlib (L, plugin_funcs);
   lua_setglobal (L, "WpPlugin");
 
+  luaL_newlib (L, settings_methods);
+  lua_setglobal (L, "WpSettings");
+
   wp_lua_scripting_pod_init (L);
   wp_lua_scripting_json_init (L);
 

modules/module-lua-scripting/api/api.lua

@@ -210,4 +210,6 @@ SANDBOX_EXPORT = {
   State = WpState_new,
   LocalModule = WpImplModule_new,
   ImplMetadata = WpImplMetadata_new,
+  Settings = WpSettings,
+  I18n = I18n
 }

modules/module-settings.c

@@ -133,8 +133,8 @@ do_parse_settings (void *data, const char *location,
   struct data *d = data;
   WpTransition *transition = d->transition;
   WpSettingsPlugin *self = wp_transition_get_source_object (transition);
-  g_autoptr (WpSpaJson) *json = wp_spa_json_new_from_stringn (str, len);
-  g_autoptr (WpIterator) *iter = wp_spa_json_new_iterator (json);
+  g_autoptr (WpSpaJson) json = wp_spa_json_new_from_stringn (str, len);
+  g_autoptr (WpIterator) iter = wp_spa_json_new_iterator (json);
   g_auto (GValue) item = G_VALUE_INIT;
 
 
@@ -268,7 +268,7 @@ on_metadata_activated (WpMetadata * m, GAsyncResult * res, gpointer user_data)
     wp_debug_object (self, "%s(%lu) = %s", setting, strlen(value), value);
     wp_metadata_set (m, 0, setting, "Spa:String:JSON", value);
   }
-  wp_info_object(self, "loaded settings(%d) to \"sm-settings\" metadata",
+  wp_info_object (self, "loaded settings(%d) to \"sm-settings\" metadata",
       wp_properties_get_count (self->settings));
 
 

src/main.c

@@ -49,6 +49,7 @@ enum {
   STEP_LOAD_COMPONENTS = WP_TRANSITION_STEP_CUSTOM_START,
   STEP_CONNECT,
   STEP_CHECK_MEDIA_SESSION,
+  STEP_ACTIVATE_SETTINGS,
   STEP_ACTIVATE_PLUGINS,
   STEP_ACTIVATE_SCRIPTS,
   STEP_CLEANUP,
@@ -70,7 +71,8 @@ wp_init_transition_get_next_step (WpTransition * transition, guint step)
   case WP_TRANSITION_STEP_NONE: return STEP_LOAD_COMPONENTS;
   case STEP_LOAD_COMPONENTS:    return STEP_CONNECT;
   case STEP_CONNECT:            return STEP_CHECK_MEDIA_SESSION;
-  case STEP_CHECK_MEDIA_SESSION:return STEP_ACTIVATE_PLUGINS;
+  case STEP_CHECK_MEDIA_SESSION:return STEP_ACTIVATE_SETTINGS;
+  case STEP_ACTIVATE_SETTINGS:  return STEP_ACTIVATE_PLUGINS;
   case STEP_CLEANUP:            return WP_TRANSITION_STEP_NONE;
 
   case STEP_ACTIVATE_PLUGINS: {
@@ -181,6 +183,44 @@ do_load_components(void *data, const char *location, const char *section,
   return 0;
 }
 
+static void
+on_settings_ready (WpSettings *s, GAsyncResult *res, gpointer data)
+{
+  WpCore *self = WP_CORE (data);
+  g_autoptr (GError) error = NULL;
+
+  wp_info_object(self, "wpsettings object ready");
+
+  if (!wp_object_activate_finish (WP_OBJECT (s), res, &error)) {
+    wp_debug_object (self, "wpsettings activation failed: %s", error->message);
+    return;
+  }
+
+  wp_transition_advance (WP_TRANSITION (self));
+}
+
+static void
+on_settings_plugin_ready (WpPlugin *s, GAsyncResult *res, gpointer data)
+{
+  WpInitTransition *self = WP_INIT_TRANSITION (data);
+  WpTransition *transition = WP_TRANSITION (data);
+  WpCore *core = wp_transition_get_source_object (transition);
+  g_autoptr (GError) error = NULL;
+  g_autoptr (WpSettings) settings = wp_settings_get_instance (core);
+
+  wp_info_object (self, "wpsettingsplugin object ready");
+
+  if (!wp_object_activate_finish (WP_OBJECT (s), res, &error)) {
+    wp_debug_object (self, "wpSettingsPlugin activation failed: %s",
+      error->message);
+    return;
+  }
+
+  wp_object_activate (WP_OBJECT (settings), WP_OBJECT_FEATURES_ALL, NULL,
+      (GAsyncReadyCallback) on_settings_ready, g_object_ref (self));
+
+}
+
 static void
 wp_init_transition_execute_step (WpTransition * transition, guint step)
 {
@@ -256,6 +296,23 @@ wp_init_transition_execute_step (WpTransition * transition, guint step)
     break;
   }
 
+  case STEP_ACTIVATE_SETTINGS: {
+    /* find and activate settings plugin */
+    WpPlugin *p = wp_plugin_find (core, "settings");
+    if (!p) {
+      wp_transition_return_error (transition, g_error_new (
+          WP_DOMAIN_DAEMON, WP_EXIT_CONFIG,
+          "unable to find settings plugin"));
+      return;
+    }
+    wp_info_object (self, "Activating wpsettings plugin");
+
+    wp_object_activate (WP_OBJECT (p), WP_OBJECT_FEATURES_ALL, NULL,
+        (GAsyncReadyCallback) on_settings_plugin_ready, g_object_ref (self));
+
+    break;
+  }
+
   case STEP_ACTIVATE_PLUGINS: {
     const char *engine = pw_properties_get (props, "wireplumber.script-engine");