internal-comp-loader: implement profiles inheriting other profiles

This allows to inherit all the profile definitions of another profile
before the current profile's definitions are parsed, allowing for
more complex structures to be present in the default wireplumber.conf
without too much copy-paste

lib/wp/private/internal-comp-loader.c

@@ -851,6 +851,65 @@ load_module (WpCore * core, const gchar * module_name, WpSpaJson * args,
   return ((WpModuleInitFunc) module_init) (core, args, error);
 }
 
+static gboolean
+parse_profile_description (WpProperties * profile, WpSpaJson * all_profiles_j,
+    const gchar * profile_name, GPtrArray * inherited_set, GError ** error)
+{
+  g_autoptr (WpSpaJson) profile_j = NULL;
+  g_autoptr (WpSpaJson) inherits_j = NULL;
+
+  if (!all_profiles_j) {
+    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+        "wireplumber.profiles section does not exist in the configuration");
+    return FALSE;
+  }
+
+  if (!wp_spa_json_is_object (all_profiles_j)) {
+    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+        "wireplumber.profiles section is not an object");
+    return FALSE;
+  }
+
+  if (!wp_spa_json_object_get (all_profiles_j, profile_name, "J", &profile_j, NULL)) {
+    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+        "profile '%s' not found in the configuration", profile_name);
+    return FALSE;
+  }
+
+  if (!wp_spa_json_is_object (profile_j)) {
+    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+        "profile description of '%s' is not an object", profile_name);
+    return FALSE;
+  }
+
+  /* mark as inherited */
+  g_ptr_array_add (inherited_set, g_strdup (profile_name));
+
+  if (wp_spa_json_object_get (profile_j, "inherits", "J", &inherits_j, NULL) &&
+      wp_spa_json_is_array (inherits_j)) {
+    g_autoptr (WpIterator) it = wp_spa_json_new_iterator (inherits_j);
+    g_auto (GValue) item = G_VALUE_INIT;
+
+    for (; wp_iterator_next (it, &item); g_value_unset (&item)) {
+      WpSpaJson *inherited_j = g_value_get_boxed (&item);
+      g_autofree gchar *inherited_profile = wp_spa_json_to_string (inherited_j);
+
+      /* skip if already inherited - avoid loops */
+      if (g_ptr_array_find_with_equal_func (inherited_set, inherited_profile,
+              g_str_equal, NULL))
+        continue;
+
+      if (!parse_profile_description (profile, all_profiles_j, inherited_profile,
+              inherited_set, error))
+        return FALSE;
+    }
+  }
+
+  wp_properties_update_from_json (profile, profile_j);
+  wp_properties_set (profile, "inherits", NULL);
+  return TRUE;
+}
+
 static gboolean
 wp_internal_comp_loader_supports_type (WpComponentLoader * cl,
     const gchar * type)
@@ -878,25 +937,21 @@ wp_internal_comp_loader_load (WpComponentLoader * self, WpCore * core,
       /* component name is the profile name;
          component list and profile features are loaded from config */
       g_autoptr (WpConf) conf = wp_core_get_conf (core);
+      g_autoptr (GPtrArray) inherited_set = g_ptr_array_new_with_free_func (g_free);
       g_autoptr (WpSpaJson) all_profiles_j = NULL;
-      g_autoptr (WpSpaJson) profile_j = NULL;
+      g_autoptr (GError) error = NULL;
       const gchar *profile_name = component;
 
       all_profiles_j = wp_conf_get_section (conf, "wireplumber.profiles");
-      if (all_profiles_j)
-        wp_spa_json_object_get (all_profiles_j, profile_name, "J", &profile_j, NULL);
 
-      if (!profile_j) {
+      if (!parse_profile_description (profile, all_profiles_j, profile_name,
+              inherited_set, &error)) {
         g_autoptr (GTask) task = g_task_new (self, cancellable, callback, data);
         g_task_set_source_tag (task, wp_internal_comp_loader_load);
-        g_task_return_new_error (G_TASK (task), WP_DOMAIN_LIBRARY,
-            WP_LIBRARY_ERROR_INVALID_ARGUMENT,
-            "profile '%s' not found in configuration", profile_name);
+        g_task_return_error (G_TASK (task), g_steal_pointer (&error));
         return;
       }
 
-      wp_properties_update_from_json (profile, profile_j);
-
       components = wp_conf_get_section (conf, "wireplumber.components");
       rules = wp_conf_get_section (conf, "wireplumber.components.rules");
     }

tests/wp/component-loader.conf

@@ -3,8 +3,14 @@ context.modules = [
 ]
 
 wireplumber.profiles = {
-  test = {
+  test_inherited = {
     virtual.four = required
+    support.zero = required
+  }
+
+  test = {
+    inherits = [ test_inherited ]
+    support.zero = disabled
     support.nine = required
     support.ten = required
     support.eleven = required
@@ -15,6 +21,11 @@ wireplumber.components = [
   # expected load order:
   # five, one, seven, ten, eleven, six, two, three, four, nine
   # eight is not loaded - optional feature
+  {
+    name = zero
+    type = test
+    provides = support.zero
+  }
   {
     name = one
     type = test