implement route-settings metadata and notification volume

Make a module that creates a route-settings metadata and provides
some helper functions to parse the json fields.

Load the route-settings module in the policy.

Move the Notification settings to the metadata. Listen for metadata
updates and update our state table.

Fixes #51

modules/meson.build

@@ -58,6 +58,17 @@ shared_library(
   dependencies : [wp_dep, pipewire_dep],
 )
 
+shared_library(
+  'wireplumber-module-route-settings-api',
+  [
+    'module-route-settings-api.c',
+  ],
+  c_args : [common_c_args, '-DG_LOG_DOMAIN="m-route-settings-api"'],
+  install : true,
+  install_dir : wireplumber_module_dir,
+  dependencies : [wp_dep, pipewire_dep],
+)
+
 subdir('module-reserve-device')
 shared_library(
   'wireplumber-module-reserve-device',

modules/module-route-settings-api.c

@@ -0,0 +1,138 @@
+/* WirePlumber
+ *
+ * Copyright © 2021 Collabora Ltd.
+ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <wp/wp.h>
+#include <pipewire/keys.h>
+#include <spa/utils/json.h>
+
+struct _WpRouteSettingsApi
+{
+  WpPlugin parent;
+
+  WpImplMetadata *metadata;
+};
+
+enum {
+  ACTION_CONVERT,
+  N_SIGNALS
+};
+
+static guint signals[N_SIGNALS] = {0};
+
+G_DECLARE_FINAL_TYPE (WpRouteSettingsApi, wp_route_settings_api,
+                      WP, ROUTE_SETTINGS_API, WpPlugin)
+G_DEFINE_TYPE (WpRouteSettingsApi, wp_route_settings_api, WP_TYPE_PLUGIN)
+
+static void
+wp_route_settings_api_init (WpRouteSettingsApi * self)
+{
+}
+
+static void
+on_metadata_activated (GObject * obj, GAsyncResult * res, gpointer user_data)
+{
+  WpTransition * transition = WP_TRANSITION (user_data);
+  WpRouteSettingsApi * self = wp_transition_get_source_object (transition);
+  g_autoptr (GError) error = NULL;
+
+  if (!wp_object_activate_finish (WP_OBJECT (obj), res, &error)) {
+    g_clear_object (&self->metadata);
+    g_prefix_error (&error, "Failed to activate WpImplMetadata: ");
+    wp_transition_return_error (transition, g_steal_pointer (&error));
+    return;
+  }
+
+  wp_object_update_features (WP_OBJECT (self), WP_PLUGIN_FEATURE_ENABLED, 0);
+}
+
+static void
+wp_route_settings_api_enable (WpPlugin * plugin, WpTransition * transition)
+{
+  WpRouteSettingsApi * self = WP_ROUTE_SETTINGS_API (plugin);
+  g_autoptr (WpCore) core = wp_object_get_core (WP_OBJECT (plugin));
+  g_return_if_fail (core);
+
+  self->metadata = wp_impl_metadata_new_full (core, "route-settings", NULL);
+  wp_object_activate (WP_OBJECT (self->metadata),
+        WP_OBJECT_FEATURES_ALL, NULL, on_metadata_activated, transition);
+}
+
+static void
+wp_route_settings_api_disable (WpPlugin * plugin)
+{
+  WpRouteSettingsApi * self = WP_ROUTE_SETTINGS_API (plugin);
+  g_clear_object (&self->metadata);
+}
+
+static gchar *
+wp_route_settings_api_convert (WpRouteSettingsApi * self,
+    const gchar * json, const gchar *field)
+{
+  struct spa_json it[3];
+  char k[128];
+
+  spa_json_init(&it[0], json, strlen(json));
+  if (spa_json_enter_object(&it[0], &it[1]) <= 0)
+    return NULL;
+
+  while (spa_json_get_string(&it[1], k, sizeof(k)-1) > 0) {
+    int len;
+    const char *value;
+
+    if (strcmp(k, field) != 0)
+      continue;
+
+    if ((len = spa_json_next(&it[1], &value)) <= 0)
+      break;
+
+    if (spa_json_is_null(value, len))
+      return NULL;
+    else if (spa_json_is_array(value, len)) {
+      GString *str;
+      spa_json_enter(&it[1], &it[2]);
+      str = g_string_new("");
+      while ((len = spa_json_next(&it[2], &value)) > 0) {
+        char v[1024];
+	if (len > 1023)
+          continue;
+        spa_json_parse_string(value, len, v);
+        g_string_append_printf(str, "%s;", v);
+      }
+      return g_string_free(str, false);
+    }
+    else
+      return g_strndup(value, len);
+  }
+  return NULL;
+}
+
+static void
+wp_route_settings_api_class_init (WpRouteSettingsApiClass * klass)
+{
+  WpPluginClass *plugin_class = (WpPluginClass *) klass;
+
+  plugin_class->enable = wp_route_settings_api_enable;
+  plugin_class->disable = wp_route_settings_api_disable;
+
+  signals[ACTION_CONVERT] = g_signal_new_class_handler (
+      "convert", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+      (GCallback) wp_route_settings_api_convert,
+      NULL, NULL, NULL,
+      G_TYPE_STRING, 2, G_TYPE_STRING, G_TYPE_STRING);
+}
+
+WP_PLUGIN_EXPORT gboolean
+wireplumber__module_init (WpCore * core, GVariant * args, GError ** error)
+{
+  wp_plugin_register (g_object_new (wp_route_settings_api_get_type (),
+          "name", "route-settings-api",
+          "core", core,
+          NULL));
+  return TRUE;
+}

src/config/policy.lua.d/10-default-policy.lua

@@ -22,6 +22,9 @@ function default_policy.enable()
   -- API to access default nodes from scripts
   load_module("default-nodes-api")
 
+  -- API to access volume of streams from scripts
+  load_module("route-settings-api")
+
   -- API to access mixer controls, needed for volume ducking
   load_module("mixer-api")
 

src/scripts/restore-stream.lua

@@ -12,6 +12,8 @@
 state = State("restore-stream")
 state_table = state:load()
 
+route_settings = Plugin.find("route-settings-api")
+
 -- simple serializer {"foo", "bar"} -> "foo;bar;"
 function serializeArray(a)
   local str = ""
@@ -22,7 +24,7 @@ function serializeArray(a)
 end
 
 -- simple deserializer "foo;bar;" -> {"foo", "bar"}
-function parseArray(str, convert_value)
+function parseArray(str, convert_value, with_type)
   local array = {}
   local pos = 1
   while true do
@@ -36,6 +38,9 @@ function parseArray(str, convert_value)
       break
     end
   end
+  if with_type then
+    array["pod_type"] = "Array"
+  end
   return array
 end
 
@@ -139,6 +144,76 @@ function restoreTarget(node, target_name)
   end
 end
 
+function jsonTable(val, name)
+  local tmp = ""
+  local count = 0
+
+  if name then tmp = tmp .. string.format("%q", name) .. ": " end
+
+  if type(val) == "table" then
+    if val["pod_type"] == "Array" then
+      tmp = tmp .. "["
+      for _, v in ipairs(val) do
+	if count > 0 then tmp = tmp .. "," end
+        tmp = tmp .. jsonTable(v)
+	count = count + 1
+      end
+      tmp = tmp .. "]"
+    else
+      tmp = tmp .. "{"
+      for k, v in pairs(val) do
+	if count > 0 then tmp = tmp .. "," end
+        tmp = tmp .. jsonTable(v, k)
+	count = count + 1
+      end
+      tmp = tmp .. "}"
+    end
+  elseif type(val) == "number" then
+    tmp = tmp .. tostring(val)
+  elseif type(val) == "string" then
+    tmp = tmp .. string.format("%q", val)
+  elseif type(val) == "boolean" then
+    tmp = tmp .. (val and "true" or "false")
+  else
+    tmp = tmp .. "\"[type:" .. type(val) .. "]\""
+  end
+  return tmp
+end
+
+function moveToMetadata(key_base, metadata)
+  local route_table = { }
+  local count = 0
+
+  key = "restore.stream." .. key_base
+  key = string.gsub(key, ":", ".", 1);
+
+  local str = state_table[key_base .. ":volume"]
+  if str then
+    route_table["volume"] = tonumber(str)
+    count = count + 1;
+  end
+  local str = state_table[key_base .. ":mute"]
+  if str then
+    route_table["mute"] = str == "true"
+    count = count + 1;
+  end
+  local str = state_table[key_base .. ":channelVolumes"]
+  if str then
+    route_table["volumes"] = parseArray(str, tonumber, true)
+    count = count + 1;
+  end
+  local str = state_table[key_base .. ":channelMap"]
+  if str then
+    route_table["channels"] = parseArray(str, nil, true)
+    count = count + 1;
+  end
+
+  if count > 0 then
+    metadata:set(0, key, "Spa:String:JSON", jsonTable(route_table));
+  end
+end
+
+
 function saveStream(node)
   local key_base = findSuitableKey(node)
   if not key_base then
@@ -240,6 +315,55 @@ metadata_om:connect("object-added", function (om, metadata)
 end)
 metadata_om:activate()
 
+function handleRouteSettings(subject, key, type, value)
+  if type ~= "Spa:String:JSON" then
+    return
+  end
+  if string.find(key, "^restore.stream.") == nil then
+    return
+  end
+
+  local key_base = string.sub(key, string.len("restore.stream.") + 1)
+  local str;
+
+  key_base = string.gsub(key_base, "%.", ":", 1);
+
+  str = route_settings:call("convert", value, "volume");
+  if str then
+      state_table[key_base .. ":volume"] = str
+  end
+  str = route_settings:call("convert", value, "mute");
+  if str then
+      state_table[key_base .. ":mute"] = str
+  end
+  str = route_settings:call("convert", value, "channels");
+  if str then
+      state_table[key_base .. ":channelMap"] = str
+  end
+  str = route_settings:call("convert", value, "volumes");
+  if str then
+    state_table[key_base .. ":channelVolumes"] = str
+  end
+
+  storeAfterTimeout()
+end
+
+rs_metadata_om = ObjectManager {
+  Interest {
+    type = "metadata",
+    Constraint { "metadata.name", "=", "route-settings" },
+  }
+}
+rs_metadata_om:connect("object-added", function (om, metadata)
+  -- copy state into the metadata
+  moveToMetadata("Output/Audio:media.role:Notification", metadata)
+  -- watch for changes
+  metadata:connect("changed", function (m, subject, key, type, value)
+    handleRouteSettings(subject, key, type, value)
+  end)
+end)
+rs_metadata_om:activate()
+
 allnodes_om = ObjectManager { Interest { type = "node" } }
 allnodes_om:activate()