endpoints: Switch endpoints config to JSON

- Move the endpoints defination to wireplumber.conf under a new section
  in the form of two JSON objects, namely endpoints and
  endpoints-roles.
- Treat the endpoint objects as settings, for the sake of loading,
  parsing and querying.
- m-settings loads the objects and WpSettings parses them as any other
  settings.
- Make the following changes in endpoint scripts.
   - Get the endpoint settings using the _get_string() API.
   - Parse and use the data.
   - Remove references to the config/lua
- Remove the endpoints defination in config/lua

modules/module-settings.c

@@ -146,10 +146,10 @@ do_parse_settings (void *data, const char *location,
   g_auto (GValue) item = G_VALUE_INIT;
 
   if (!wp_spa_json_is_object (json)) {
-    /* "wireplumber.settings" section has to be a JSON object element. */
+    /* section has to be a JSON object element. */
     wp_transition_return_error (transition, g_error_new (
       WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_OPERATION_FAILED,
-        "failed to parse \"wireplumber.settings\" settings cannot be loaded"));
+        "failed to parse the section"));
     return -EINVAL;
   }
 
@@ -186,6 +186,12 @@ do_parse_settings (void *data, const char *location,
  return 0;
 }
 
+static int
+do_parse_endpoints (void *data, const char *location,
+    const char *section, const char *str, size_t len)
+{
+  do_parse_settings (data, location, section, str, len);
+}
 
 static void
 on_metadata_activated (WpMetadata * m, GAsyncResult * res, gpointer user_data)
@@ -230,6 +236,22 @@ on_metadata_activated (WpMetadata * m, GAsyncResult * res, gpointer user_data)
     return;
   }
 
+  if (pw_context_conf_section_for_each (pw_ctx, "wireplumber.endpoints",
+      do_parse_endpoints, &data) < 0)
+    return;
+
+  if (data.count == 0) {
+    /*
+     * either the "wireplumber.endpoints" is not found or not defined as a
+     * valid JSON object element.
+     */
+    wp_transition_return_error (transition, g_error_new (
+      WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_OPERATION_FAILED,
+      "No endpoints present in the context conf file: endpoints "
+      "are not loaded"));
+    return;
+  }
+
   if (!self->use_persistent_storage) {
 
     /* use parsed settings from .conf file */

src/config/policy.lua.d/50-endpoints-config.lua

@@ -1,95 +0,0 @@
--- uncomment to enable role-based endpoints
--- this is not yet ready for desktop use
---
---[[
-
-default_policy.policy.roles = {
-  ["Capture"] = {
-    ["alias"] = { "Multimedia", "Music", "Voice", "Capture" },
-    ["priority"] = 25,
-    ["action.default"] = "cork",
-    ["action.capture"] = "mix",
-    ["media.class"] = "Audio/Source",
-  },
-  ["Multimedia"] = {
-    ["alias"] = { "Movie", "Music", "Game" },
-    ["priority"] = 25,
-    ["action.default"] = "cork",
-  },
-  ["Speech-Low"] = {
-    ["priority"] = 30,
-    ["action.default"] = "cork",
-    ["action.Speech-Low"] = "mix",
-  },
-  ["Custom-Low"] = {
-    ["priority"] = 35,
-    ["action.default"] = "cork",
-    ["action.Custom-Low"] = "mix",
-  },
-  ["Navigation"] = {
-    ["priority"] = 50,
-    ["action.default"] = "duck",
-    ["action.Navigation"] = "mix",
-  },
-  ["Speech-High"] = {
-    ["priority"] = 60,
-    ["action.default"] = "cork",
-    ["action.Speech-High"] = "mix",
-  },
-  ["Custom-High"] = {
-    ["priority"] = 65,
-    ["action.default"] = "cork",
-    ["action.Custom-High"] = "mix",
-  },
-  ["Communication"] = {
-    ["priority"] = 75,
-    ["action.default"] = "cork",
-    ["action.Communication"] = "mix",
-  },
-  ["Emergency"] = {
-    ["alias"] = { "Alert" },
-    ["priority"] = 99,
-    ["action.default"] = "cork",
-    ["action.Emergency"] = "mix",
-  },
-}
-
-default_policy.endpoints = {
-  ["endpoint.capture"] = {
-    ["media.class"] = "Audio/Source",
-    ["role"] = "Capture",
-  },
-  ["endpoint.multimedia"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Multimedia",
-  },
-  ["endpoint.speech_low"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Speech-Low",
-  },
-  ["endpoint.custom_low"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Custom-Low",
-  },
-  ["endpoint.navigation"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Navigation",
-  },
-  ["endpoint.speech_high"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Speech-High",
-  },
-  ["endpoint.custom_high"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Custom-High",
-  },
-  ["endpoint.communication"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Communication",
-  },
-  ["endpoint.emergency"] = {
-    ["media.class"] = "Audio/Sink",
-    ["role"] = "Emergency",
-  },
-}
-]]--

src/config/wireplumber.conf

@@ -141,3 +141,95 @@ wireplumber.settings = {
   persistent.settings = false
 }
 
+wireplumber.endpoints = {
+  # endpoints = {
+  #   endpoint.capture = {
+  #     media.class = "Audio/Source"
+  #     role = "Capture"
+  #   }
+  #   endpoint.multimedia = {
+  #     media.class = "Audio/Sink"
+  #     role = "Multimedia"
+  #   }
+  #   endpoint.speech_low = {
+  #     media.class = "Audio/Sink"
+  #     role = "Speech-Low"
+  #   }
+  #   endpoint.custom_low = {
+  #     media.class = "Audio/Sink"
+  #     role = "Custom-Low"
+  #   }
+  #   endpoint.navigation = {
+  #     media.class = "Audio/Sink"
+  #     role = "Navigation"
+  #   }
+  #   endpoint.speech_high = {
+  #     media.class = "Audio/Sink"
+  #     role = "Speech-High"
+  #   }
+  #   endpoint.custom_high = {
+  #     media.class = "Audio/Sink"
+  #     role = "Custom-High"
+  #   }
+  #   endpoint.communication = {
+  #     media.class = "Audio/Sink"
+  #     role = "Communication"
+  #   }
+  #   endpoint.emergency = {
+  #     media.class = "Audio/Sink"
+  #     role = "Emergency"
+  #   }
+  # }
+
+  # endpoints-roles = {
+  #   Capture = {
+  #     alias = [ "Multimedia", "Music", "Voice", "Capture" ]
+  #     priority = 25
+  #     action.default = "cork"
+  #     action.capture = "mix"
+  #     media.class = "Audio/Source"
+  #   }
+  #   Multimedia = {
+  #     alias = [ "Movie" "Music" "Game" ]
+  #     priority = 25
+  #     action.default = "cork"
+  #   }
+  #   Speech-Low = {
+  #     priority = 30
+  #     action.default = "cork"
+  #     action.Speech-Low = "mix"
+  #   }
+  #   Custom-Low = {
+  #     priority = 35
+  #     action.default = "cork"
+  #     action.Custom-Low = "mix"
+  #   }
+  #   Navigation = {
+  #     priority = 50
+  #     action.default = "duck"
+  #     action.Navigation = "mix"
+  #   }
+  #   Speech-High = {
+  #     priority = 60
+  #     action.default = "cork"
+  #     action.Speech-High = "mix"
+  #   }
+  #   Custom-High = {
+  #     priority = 65
+  #     action.default = "cork"
+  #     action.Custom-High = "mix"
+  #   }
+  #   Communication = {
+  #     priority = 75
+  #     action.default = "cork"
+  #     action.Communication = "mix"
+  #   }
+  #   Emergency = {
+  #     alias = [ "Alert" ]
+  #     priority = 99
+  #     action.default = "cork"
+  #     action.Emergency = "mix"
+  #   }
+  # }
+}
+

src/scripts/policy-endpoint-client-links.lua

@@ -6,12 +6,18 @@
 -- SPDX-License-Identifier: MIT
 
 local config = ... or {}
-config.roles = config.roles or {}
+local roles = {}
+
 config["duck.level"] = config["duck.level"] or 0.3
+local endpoint_roles_setting = Settings.get_string ("endpoints-roles")
+if endpoint_roles_setting then
+  json = Json.Raw (endpoint_roles_setting)
+  roles = json:parse ()
+end
 
 function findRole(role)
-  if role and not config.roles[role] then
-    for r, p in pairs(config.roles) do
+  if role and not roles[role] then
+    for r, p in pairs(roles) do
       if type(p.alias) == "table" then
         for i = 1, #(p.alias), 1 do
           if role == p.alias[i] then
@@ -25,17 +31,17 @@ function findRole(role)
 end
 
 function priorityForRole(role)
-  local r = role and config.roles[role] or nil
+  local r = role and roles[role] or nil
   return r and r.priority or 0
 end
 
 function getAction(dominant_role, other_role)
   -- default to "mix" if the role is not configured
-  if not dominant_role or not config.roles[dominant_role] then
+  if not dominant_role or not roles[dominant_role] then
     return "mix"
   end
 
-  local role_config = config.roles[dominant_role]
+  local role_config = roles[dominant_role]
   return role_config["action." .. other_role]
       or role_config["action.default"]
       or "mix"

src/scripts/policy-endpoint-client.lua

@@ -6,8 +6,12 @@
 -- SPDX-License-Identifier: MIT
 
 -- Receive script arguments from config.lua
-local config = ... or {}
-config.roles = config.roles or {}
+local roles = {}
+local endpoint_roles_setting = Settings.get_string ("endpoints-roles")
+if endpoint_roles_setting then
+  json = Json.Raw (endpoint_roles_setting)
+  roles = json:parse ()
+end
 
 local self = {}
 self.scanning = false
@@ -38,9 +42,9 @@ function scheduleRescan ()
 end
 
 function findRole(role, tmc)
-  if role and not config.roles[role] then
+  if role and not roles[role] then
     -- find the role with matching alias
-    for r, p in pairs(config.roles) do
+    for r, p in pairs(roles) do
       -- default media class can be overridden in the role config data
       mc = p["media.class"] or "Audio/Sink"
       if (type(p.alias) == "table" and tmc == mc) then
@@ -55,7 +59,7 @@ function findRole(role, tmc)
     -- otherwise get the lowest priority role
     local lowest_priority_p = nil
     local lowest_priority_r = nil
-    for r, p in pairs(config.roles) do
+    for r, p in pairs(roles) do
       mc = p["media.class"] or "Audio/Sink"
       if tmc == mc and (lowest_priority_p == nil or
           p.priority < lowest_priority_p.priority) then

src/scripts/static-endpoints.lua

@@ -6,7 +6,12 @@
 -- SPDX-License-Identifier: MIT
 
 -- Receive script arguments from config.lua
-local endpoints_config = ...
+local endpoints = {}
+local endpoint_setting = Settings.get_string ("endpoints")
+if endpoint_setting then
+  json = Json.Raw (endpoint_setting)
+  endpoints = json:parse ()
+end
 
 function createEndpoint (factory_name, properties)
   -- create endpoint
@@ -30,7 +35,7 @@ function createEndpoint (factory_name, properties)
 end
 
 
-for name, properties in pairs(endpoints_config) do
+for name, properties in pairs(endpoints) do
   properties["name"] = name
   createEndpoint ("si-audio-endpoint", properties)
 end