comp-loader: add support for wireplumber.components.rules

This is a new rules section that allows defining rules to modify
component definitions. This is useful to add repetitive dependencies,
for example, as in the case of "type = script/lua" that always requires
the "support.lua-scripting" feature. This can also be useful to modify
other component properties, such as the arguments, in overriding
configuration files, without needing to redefine the whole components
section.

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

@@ -83,12 +83,83 @@ get_feature_state (WpProperties * dict, const gchar * feature)
   }
 }
 
-static ComponentData *
+static gboolean
-component_data_new_from_json (WpSpaJson * json, WpProperties * features,
+component_rule_match_cb (gpointer data, const gchar * action, WpSpaJson * value,
     GError ** error)
+{
+  WpProperties *props = data;
+  g_autoptr (WpIterator) it = NULL;
+  g_auto (GValue) item = G_VALUE_INIT;
+  gboolean merge;
+
+  if (!wp_spa_json_is_object (value)) {
+    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+        "expected JSON object instead of: %.*s", (int) wp_spa_json_get_size (value),
+        wp_spa_json_get_data (value));
+    return FALSE;
+  }
+
+  if (g_str_equal (action, "merge")) {
+    merge = TRUE;
+  } else if (g_str_equal (action, "override")) {
+    merge = FALSE;
+  } else {
+    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+        "invalid action '%s' in component rules", action);
+    return FALSE;
+  }
+
+  it = wp_spa_json_new_iterator (value);
+
+  do {
+    g_autofree gchar *key = NULL;
+    g_autofree gchar *val = NULL;
+    const gchar *old_val = NULL;
+
+    /* extract key */
+    if (!wp_iterator_next (it, &item))
+      break;
+    key = wp_spa_json_to_string (g_value_get_boxed (&item));
+    g_value_unset (&item);
+
+    /* extract value */
+    if (!wp_iterator_next (it, &item)) {
+      g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
+          "expected value for key '%s' in component rules", key);
+      return FALSE;
+    }
+    val = wp_spa_json_to_string (g_value_get_boxed (&item));
+    g_value_unset (&item);
+
+    old_val = wp_properties_get (props, key);
+
+    /* override if not merging or if the value is not a container */
+    if (!merge || !old_val || (*old_val != '[' && *old_val != '{')) {
+      wp_properties_set (props, key, val);
+    }
+    else {
+      g_autoptr (WpSpaJson) old_json = NULL;
+      g_autoptr (WpSpaJson) new_json = NULL;
+      g_autoptr (WpSpaJson) merged_json = NULL;
+
+      old_json = wp_spa_json_new_wrap_string (old_val);
+      new_json = wp_spa_json_new_wrap_string (val);
+      merged_json = wp_json_utils_merge_containers (old_json, new_json);
+      wp_properties_set (props, key,
+          merged_json ? wp_spa_json_get_data (merged_json) : val);
+    }
+  } while (TRUE);
+
+  return TRUE;
+}
+
+static ComponentData *
+component_data_new_from_json (WpSpaJson * json, WpProperties * features,
+    WpSpaJson * rules, GError ** error)
 {
   g_autoptr (ComponentData) comp = NULL;
-  g_autoptr (WpSpaJson) comp_reqs = NULL, comp_wants = NULL;
+  g_autoptr (WpProperties) props = NULL;
+  const gchar *str;
 
   if (!wp_spa_json_is_object (json)) {
     g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
@@ -102,17 +173,24 @@ component_data_new_from_json (WpSpaJson * json, WpProperties * features,
   comp->requires = g_ptr_array_new_with_free_func (g_free);
   comp->wants = g_ptr_array_new_with_free_func (g_free);
 
-  if (!wp_spa_json_object_get (json, "type", "s", &comp->type, NULL)) {
+  props = wp_properties_new_json (json);
+  if (rules && !wp_json_utils_match_rules (rules, props, component_rule_match_cb,
+          props, error))
+    return NULL;
+
+  if (!(comp->type = g_strdup (wp_properties_get (props, "type")))) {
     g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
         "component 'type' is required at: %.*s", (int) wp_spa_json_get_size (json),
         wp_spa_json_get_data (json));
     return NULL;
   }
 
-  wp_spa_json_object_get (json, "name", "s", &comp->name, NULL);
+  comp->name = g_strdup (wp_properties_get (props, "name"));
-  wp_spa_json_object_get (json, "arguments", "J", &comp->arguments, NULL);
+  str = wp_properties_get (props, "arguments");
+  comp->arguments = str ? wp_spa_json_new_from_string (str) : NULL;
 
-  if (wp_spa_json_object_get (json, "provides", "s", &comp->provides, NULL)) {
+  if ((str = wp_properties_get (props, "provides"))) {
+    comp->provides = g_strdup (str);
     comp->state = get_feature_state (features, comp->provides);
     if (comp->name) {
       comp->printable_id =
@@ -126,7 +204,8 @@ component_data_new_from_json (WpSpaJson * json, WpProperties * features,
     comp->printable_id = g_strdup_printf ("[%s: %s]", comp->type, comp->name);
   }
 
-  if (wp_spa_json_object_get (json, "requires", "J", &comp_reqs, NULL)) {
+  if ((str = wp_properties_get (props, "requires"))) {
+    g_autoptr (WpSpaJson) comp_reqs = wp_spa_json_new_wrap_string (str);
     g_autoptr (WpIterator) it = wp_spa_json_new_iterator (comp_reqs);
     g_auto (GValue) item = G_VALUE_INIT;
 
@@ -136,7 +215,8 @@ component_data_new_from_json (WpSpaJson * json, WpProperties * features,
     }
   }
 
-  if (wp_spa_json_object_get (json, "wants", "J", &comp_wants, NULL)) {
+  if ((str = wp_properties_get (props, "wants"))) {
+    g_autoptr (WpSpaJson) comp_wants = wp_spa_json_new_wrap_string (str);
     g_autoptr (WpIterator) it = wp_spa_json_new_iterator (comp_wants);
     g_auto (GValue) item = G_VALUE_INIT;
 
@@ -171,6 +251,8 @@ struct _WpComponentArrayLoadTask
   WpSpaJson *json;
   /* the features profile */
   WpProperties *profile;
+  /* the rules to apply on each component description */
+  WpSpaJson *rules;
   /* all components that provide a feature; key: comp->provides, value: comp */
   GHashTable *feat_components;
   /* the final sorted list of components to load */
@@ -317,7 +399,7 @@ parse_components (WpComponentArrayLoadTask * self, GError ** error)
     GError *e = NULL;
     g_autoptr (ComponentData) comp = NULL;
 
-    if (!(comp = component_data_new_from_json (cjson, self->profile, &e))) {
+    if (!(comp = component_data_new_from_json (cjson, self->profile, self->rules, &e))) {
       g_propagate_error (error, e);
       return FALSE;
     }
@@ -459,6 +541,7 @@ wp_component_array_load_task_finalize (GObject * object)
   g_clear_pointer (&self->feat_components, g_hash_table_unref);
   g_clear_pointer (&self->components, g_ptr_array_unref);
   g_clear_pointer (&self->profile, wp_properties_unref);
+  g_clear_pointer (&self->rules, wp_spa_json_unref);
   g_clear_pointer (&self->json, wp_spa_json_unref);
 
   G_OBJECT_CLASS (wp_component_array_load_task_parent_class)->finalize (object);
@@ -478,7 +561,7 @@ wp_component_array_load_task_class_init (WpComponentArrayLoadTaskClass * klass)
 
 static WpTransition *
 wp_component_array_load_task_new (WpSpaJson * json, WpProperties * profile,
-    gpointer source_object, GCancellable * cancellable,
+    WpSpaJson * rules, gpointer source_object, GCancellable * cancellable,
     GAsyncReadyCallback callback, gpointer callback_data)
 {
   WpTransition *t = wp_transition_new (wp_component_array_load_task_get_type (),
@@ -486,6 +569,7 @@ wp_component_array_load_task_new (WpSpaJson * json, WpProperties * profile,
   WpComponentArrayLoadTask *task = WP_COMPONENT_ARRAY_LOAD_TASK (t);
   task->json = wp_spa_json_ref (json);
   task->profile = wp_properties_ref (profile);
+  task->rules = rules ? wp_spa_json_ref (rules) : NULL;
   return t;
 }
 
@@ -641,23 +725,30 @@ wp_internal_comp_loader_load (WpComponentLoader * self, WpCore * core,
   if (g_str_equal (type, "profile") || g_str_equal (type, "array")) {
     WpTransition *task = NULL;
     g_autoptr (WpSpaJson) components = NULL;
+    g_autoptr (WpSpaJson) rules = NULL;
     g_autoptr (WpProperties) profile = wp_properties_new_empty ();
 
     if (g_str_equal (type, "profile")) {
       /* component name is the profile name;
          component list and profile features are loaded from config */
       g_autoptr (WpConf) conf = wp_conf_get_instance (core);
-      g_autoptr (WpSpaJson) profile_json =
+      g_autoptr (WpSpaJson) profile_json = NULL;
+
+      profile_json =
           wp_conf_get_value (conf, "wireplumber.profiles", component, NULL);
       if (profile_json)
         wp_properties_update_from_json (profile, profile_json);
+
       components = wp_conf_get_section (conf, "wireplumber.components", NULL);
-    } else {
+
+      rules = wp_conf_get_section (conf, "wireplumber.components.rules", NULL);
+    }
+    else {
       /* component list is retrieved from args; profile features are empty */
       components = wp_spa_json_ref (args);
     }
 
-    task = wp_component_array_load_task_new (components, profile, self,
+    task = wp_component_array_load_task_new (components, profile, rules, self,
         cancellable, callback, data);
     wp_transition_set_data (task, g_object_ref (core), g_object_unref);
     wp_transition_set_source_tag (task, wp_internal_comp_loader_load);

src/config/wireplumber.conf

@@ -214,7 +214,6 @@ wireplumber.components = [
     name = metadata.lua, type = script/lua
     arguments = { metadata.name = default }
     provides = metadata.default
-    requires = [ support.lua-scripting ]
   }
 
   ## Provide the "filters" pw_metadata
@@ -222,7 +221,6 @@ wireplumber.components = [
     name = metadata.lua, type = script/lua
     arguments = { metadata.name = filters }
     provides = metadata.filters
-    requires = [ support.lua-scripting ]
   }
 
   ## Device monitors' optional features
@@ -243,54 +241,49 @@ wireplumber.components = [
   {
     name = monitors/alsa.lua, type = script/lua
     provides = monitor.alsa
-    requires = [ support.lua-scripting, support.export-core ]
+    requires = [ support.export-core ]
     wants = [ monitor.alsa.reserve-device ]
   }
   {
     name = monitors/bluez.lua, type = script/lua
     provides = monitor.bluez
-    requires = [ support.lua-scripting, support.export-core ]
+    requires = [ support.export-core ]
     wants = [ monitor.bluetooth.seat-monitoring ]
   }
   {
     name = monitors/bluez-midi.lua, type = script/lua
     provides = monitor.bluez-midi
-    requires = [ support.lua-scripting, support.export-core ]
+    requires = [ support.export-core ]
     wants = [ monitor.bluetooth.seat-monitoring ]
   }
   {
     name = monitors/alsa-midi.lua, type = script/lua
     provides = monitor.alsa-midi
-    requires = [ support.lua-scripting ]
     wants = [ monitor.alsa-midi.monitoring ]
   }
   ## v4l2 monitor hooks
   {
     name = monitors/v4l2/name-device.lua, type = script/lua
     provides = hooks.monitor.v4l2-name-device
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
     name = monitors/v4l2/create-device.lua, type = script/lua
     provides = hooks.monitor.v4l2-create-device
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
     name = monitors/v4l2/name-node.lua, type = script/lua
     provides = hooks.monitor.v4l2-name-node
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
     name = monitors/v4l2/create-node.lua, type = script/lua
     provides = hooks.monitor.v4l2-create-node
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
@@ -304,8 +297,7 @@ wireplumber.components = [
   {
     name = monitors/v4l2/enumerate-device.lua, type = script/lua
     provides = hooks.monitor.v4l2-enumerate-device
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source,
                  monitor.v4l2.hooks ]
   }
@@ -319,29 +311,25 @@ wireplumber.components = [
   {
     name = monitors/libcamera/name-device.lua, type = script/lua
     provides = hooks.monitor.libcamera-name-device
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
     name = monitors/libcamera/create-device.lua, type = script/lua
     provides = hooks.monitor.libcamera-create-device
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
     name = monitors/libcamera/name-node.lua, type = script/lua
     provides = hooks.monitor.libcamera-name-node
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
     name = monitors/libcamera/create-node.lua, type = script/lua
     provides = hooks.monitor.libcamera-create-node
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source ]
   }
   {
@@ -355,8 +343,7 @@ wireplumber.components = [
   {
     name = monitors/libcamera/enumerate-device.lua, type = script/lua
     provides = hooks.monitor.libcamera-enumerate-device
-    requires = [ support.lua-scripting,
+    requires = [ support.export-core,
-                 support.export-core,
                  support.standard-event-source,
                  monitor.libcamera.hooks ]
   }
@@ -370,12 +357,11 @@ wireplumber.components = [
   {
     name = client/access-default.lua, type = script/lua
     provides = script.client.access-default
-    requires = [ support.lua-scripting ]
   }
   {
     name = client/access-portal.lua, type = script/lua
     provides = script.client.access-portal
-    requires = [ support.lua-scripting, support.portal-permissionstore ]
+    requires = [ support.portal-permissionstore ]
   }
   {
     type = virtual, provides = policy.client.access
@@ -387,27 +373,22 @@ wireplumber.components = [
   {
     name = device/select-profile.lua, type = script/lua
     provides = hooks.device.profile.select
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/find-best-profile.lua, type = script/lua
     provides = hooks.device.profile.find-best
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/state-profile.lua, type = script/lua
     provides = hooks.device.profile.state
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/apply-profile.lua, type = script/lua
     provides = hooks.device.profile.apply
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/autoswitch-bluetooth-profile.lua, type = script/lua
     provides = hooks.device.profile.autoswitch-bluetooth
-    requires = [ support.lua-scripting ]
   }
   {
     type = virtual, provides = policy.device.profile
@@ -422,22 +403,18 @@ wireplumber.components = [
   {
     name = device/select-routes.lua, type = script/lua
     provides = hooks.device.routes.select
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/find-best-routes.lua, type = script/lua
     provides = hooks.device.routes.find-best
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/state-routes.lua, type = script/lua
     provides = hooks.device.routes.state
-    requires = [ support.lua-scripting ]
   }
   {
     name = device/apply-routes.lua, type = script/lua
     provides = hooks.device.routes.apply
-    requires = [ support.lua-scripting ]
   }
   {
     type = virtual, provides = policy.device.routes
@@ -451,27 +428,25 @@ wireplumber.components = [
   {
     name = default-nodes/rescan.lua, type = script/lua
     provides = hooks.default-nodes.rescan
-    requires = [ support.lua-scripting ]
   }
   {
     name = default-nodes/find-selected-default-node.lua, type = script/lua
     provides = hooks.default-nodes.find-selected
-    requires = [ support.lua-scripting, metadata.default ]
+    requires = [ metadata.default ]
   }
   {
     name = default-nodes/find-best-default-node.lua, type = script/lua
     provides = hooks.default-nodes.find-best
-    requires = [ support.lua-scripting ]
   }
   {
     name = default-nodes/state-default-nodes.lua, type = script/lua
     provides = hooks.default-nodes.state
-    requires = [ support.lua-scripting, metadata.default ]
+    requires = [ metadata.default ]
   }
   {
     name = default-nodes/apply-default-node.lua, type = script/lua,
     provides = hooks.default-nodes.apply
-    requires = [ support.lua-scripting, metadata.default ]
+    requires = [ metadata.default ]
   }
   {
     type = virtual, provides = policy.default-nodes
@@ -486,74 +461,67 @@ wireplumber.components = [
   {
     name = node/create-item.lua, type = script/lua
     provides = hooks.node.create-session-item
-    requires = [ support.lua-scripting, si.audio-adapter, si.node ]
+    requires = [ si.audio-adapter, si.node ]
   }
   {
     name = node/suspend-node.lua, type = script/lua
     provides = hooks.node.suspend
-    requires = [ support.lua-scripting ]
   }
   {
     name = node/state-stream.lua, type = script/lua
     provides = hooks.stream.state
-    requires = [ support.lua-scripting ]
   }
   {
     name = linking/filter-forward-format.lua, type = script/lua
     provides = hooks.loopback.forward-format
-    requires = [ support.lua-scripting ]
   }
   {
     name = node/create-virtual-item.lua, type = script/lua
     provides = script.create-role-items
-    requires = [ support.lua-scripting, si.audio-virtual ]
+    requires = [ si.audio-virtual ]
   }
 
   ## Linking hooks
   {
     name = linking/rescan.lua, type = script/lua
     provides = hooks.linking.rescan
-    requires = [ support.lua-scripting ]
   }
   {
     name = linking/move-follow.lua, type = script/lua
     provides = hooks.linking.move-follow
-    requires = [ support.lua-scripting ]
   }
   {
     name = linking/find-defined-target.lua, type = script/lua
     provides = hooks.linking.target.find-defined
-    requires = [ support.lua-scripting ]
   }
   {
     name = linking/find-filter-target.lua, type = script/lua
     provides = hooks.linking.target.find-filter
-    requires = [ support.lua-scripting, metadata.filters ]
+    requires = [ metadata.filters ]
   }
   {
     name = linking/find-default-target.lua, type = script/lua
     provides = hooks.linking.target.find-default
-    requires = [ support.lua-scripting, api.default-nodes ]
+    requires = [ api.default-nodes ]
   }
   {
     name = linking/find-best-target.lua, type = script/lua
     provides = hooks.linking.target.find-best
-    requires = [ support.lua-scripting ]
   }
   {
     name = linking/get-filter-from-target.lua, type = script/lua
     provides = hooks.linking.target.get-filter-from
-    requires = [ support.lua-scripting, metadata.filters ]
+    requires = [ metadata.filters ]
   }
   {
     name = linking/prepare-link.lua, type = script/lua
     provides = hooks.linking.target.prepare-link
-    requires = [ support.lua-scripting, api.default-nodes ]
+    requires = [ api.default-nodes ]
   }
   {
     name = linking/link-target.lua, type = script/lua
     provides = hooks.linking.target.link
-    requires = [ support.lua-scripting, si.standard-link ]
+    requires = [ si.standard-link ]
   }
   {
     type = virtual, provides = policy.linking.standard
@@ -572,12 +540,11 @@ wireplumber.components = [
   {
     name = linking/rescan-virtual-links.lua, type = script/lua
     provides = hooks.linking.role-priority-system.links.rescan
-    requires = [ support.lua-scripting, api.mixer ]
+    requires = [ api.mixer ]
   }
   {
     name = linking/find-virtual-target.lua, type = script/lua
     provides = hooks.linking.role-priority-system.target.find
-    requires = [ support.lua-scripting ]
   }
   {
     type = virtual, provides = policy.linking.role-priority-system
@@ -619,6 +586,38 @@ wireplumber.components = [
   }
 ]
 
+wireplumber.components.rules = [
+  ## Rules to apply on top of wireplumber.components
+  ## Syntax:
+  ## {
+  ##   matches = [
+  ##     {
+  ##       [ <key> = <value> ... ]
+  ##     }
+  ##     ...
+  ##   ]
+  ##   actions = {
+  ##     <override|merge> = {
+  ##       [ <key> = <value> ... ]
+  ##     }
+  ##     ...
+  ##   }
+  ## }
+
+  {
+    matches = [
+      {
+        type = "script/lua"
+      }
+    ]
+    actions = {
+      merge = {
+        requires = [ support.lua-scripting ]
+      }
+    }
+  }
+]
+
 wireplumber.settings = {
   ## This main config file is only supposed to contain the common settings and
   ## rules. rest of the settings and rules are distributed across

tests/wp/component-loader.conf

@@ -21,17 +21,17 @@ wireplumber.components = [
     name = two
     type = test
     provides = support.two
-    requires = [ support.one support.six ]
+    requires = [ support.one ]
   }
   {
     type = virtual
     provides = virtual.four
-    requires = [ support.four ]
+    requires = [ INVALID ]
   }
   {
     name = three
     type = test
-    provides = support.three
+    provides = INVALID
     wants = [ support.two ]
   }
   {
@@ -64,3 +64,46 @@ wireplumber.components = [
     requires = [ support.four ]
   }
 ]
+
+wireplumber.components.rules = [
+  {
+    matches = [
+      {
+        name = two
+      }
+    ]
+    actions = {
+      merge = {
+        # final array should be [ support.one, support.six ]
+        # if this fails, support.six will not be loaded
+        requires = [ support.six ]
+      }
+    }
+  }
+
+  {
+    matches = [
+      {
+        name = three
+      }
+    ]
+    actions = {
+      merge = {
+        provides = support.three
+      }
+    }
+  }
+
+  {
+    matches = [
+      {
+        provides = virtual.four
+      }
+    ]
+    actions = {
+      override = {
+        requires = [ support.four ]
+      }
+    }
+  }
+]