wireplumber/modules/module-lua-scripting.c

/* WirePlumber
 *
 * Copyright © 2020 Collabora Ltd.
 *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
 *
 * SPDX-License-Identifier: MIT
 */

#include <wp/wp.h>
#include <wplua/wplua.h>
#include <pipewire/keys.h>

void wp_lua_scripting_api_init (lua_State *L);
gboolean wp_lua_scripting_load_configuration (const gchar * conf_file,
    WpCore * core, GError ** error);

struct _WpLuaScriptingPlugin
{
  WpComponentLoader parent;

  GPtrArray *scripts;
  WpCore *export_core;
  lua_State *L;
};

G_DECLARE_FINAL_TYPE (WpLuaScriptingPlugin, wp_lua_scripting_plugin,
                      WP, LUA_SCRIPTING_PLUGIN, WpComponentLoader)
G_DEFINE_TYPE (WpLuaScriptingPlugin, wp_lua_scripting_plugin,
               WP_TYPE_COMPONENT_LOADER)

static void
wp_lua_scripting_plugin_init (WpLuaScriptingPlugin * self)
{
  self->scripts = g_ptr_array_new_with_free_func (g_free);
}

static void
wp_lua_scripting_plugin_finalize (GObject * object)
{
  WpLuaScriptingPlugin * self = WP_LUA_SCRIPTING_PLUGIN (object);

  g_clear_pointer (&self->scripts, g_ptr_array_unref);

  G_OBJECT_CLASS (wp_lua_scripting_plugin_parent_class)->finalize (object);
}

static void
wp_lua_scripting_plugin_enable (WpPlugin * plugin, WpTransition * transition)
{
  WpLuaScriptingPlugin * self = WP_LUA_SCRIPTING_PLUGIN (plugin);
  g_autoptr (WpCore) core = wp_object_get_core (WP_OBJECT (plugin));

  /* initialize secondary connection to pipewire */
  self->export_core = wp_core_clone (core);
  wp_core_update_properties (self->export_core, wp_properties_new (
        PW_KEY_APP_NAME, "WirePlumber (export)",
        NULL));
  if (!wp_core_connect (self->export_core)) {
    wp_transition_return_error (transition, g_error_new (
        WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_OPERATION_FAILED,
        "failed to connect export core"));
    return;
  }

  /* init lua engine */
  self->L = wplua_new ();

  lua_pushliteral (self->L, "wireplumber_core");
  lua_pushlightuserdata (self->L, core);
  lua_settable (self->L, LUA_REGISTRYINDEX);

  lua_pushliteral (self->L, "wireplumber_export_core");
  lua_pushlightuserdata (self->L, self->export_core);
  lua_settable (self->L, LUA_REGISTRYINDEX);

  wp_lua_scripting_api_init (self->L);
  wplua_enable_sandbox (self->L, WP_LUA_SANDBOX_ISOLATE_ENV);

  /* execute scripts that were queued in for loading */
  for (guint i = 0; i < self->scripts->len; i++) {
    GError * error = NULL;
    if (!wplua_load_path (self->L, g_ptr_array_index (self->scripts, i), 0, 0, &error)) {
      wp_transition_return_error (transition, error);
      return;
    }
  }

  wp_object_update_features (WP_OBJECT (self), WP_PLUGIN_FEATURE_ENABLED, 0);
}

static void
wp_lua_scripting_plugin_disable (WpPlugin * plugin)
{
  WpLuaScriptingPlugin * self = WP_LUA_SCRIPTING_PLUGIN (plugin);

  g_clear_pointer (&self->L, wplua_free);
  g_clear_object (&self->export_core);
}

static gboolean
wp_lua_scripting_plugin_supports_type (WpComponentLoader * cl,
    const gchar * type)
{
  return (!g_strcmp0 (type, "script/lua") || !g_strcmp0 (type, "config/lua"));
}

static gchar *
find_script (const gchar * script)
{
  if (g_path_is_absolute (script) &&
      g_file_test (script, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR))
    return g_strdup (script);

  /* /etc/wireplumber/scripts */
  {
    g_autofree gchar * file = g_build_filename (
        wp_get_config_dir (), "scripts", script, NULL);

    wp_trace ("trying %s", file);

    if (g_file_test (file, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR))
      return g_steal_pointer (&file);
  }

  {
    g_autofree gchar * file = g_build_filename (
        wp_get_data_dir (), "scripts", script, NULL);

    wp_trace ("trying %s", file);

    if (g_file_test (file, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR))
      return g_steal_pointer (&file);
  }

  /* {XDG_DATA_DIRS,/usr/local/share,/usr/share}/wireplumber/scripts */
  const gchar * const * data_dirs = g_get_system_data_dirs ();
  for (; *data_dirs; data_dirs++) {
    g_autofree gchar * file = g_build_filename (
        *data_dirs, "wireplumber", "scripts", script, NULL);

    wp_trace ("trying %s", file);

    if (g_file_test (file, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR))
      return g_steal_pointer (&file);
  }
  return NULL;
}

static gboolean
wp_lua_scripting_plugin_load (WpComponentLoader * cl, const gchar * component,
    const gchar * type, GVariant * args, GError ** error)
{
  WpLuaScriptingPlugin * self = WP_LUA_SCRIPTING_PLUGIN (cl);

  /* interpret component as a script */
  if (!g_strcmp0 (type, "script/lua")) {
    gchar * file = find_script (component);
    if (!file) {
      g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
          "Could not locate script '%s'", component);
      return FALSE;
    }

    /* keep in a list and delay loading until the plugin is enabled */
    g_ptr_array_add (self->scripts, file);
    return self->L ? wplua_load_path (self->L, file, 0, 0, error) : TRUE;
  }
  /* interpret component as a configuration file */
  else if (!g_strcmp0 (type, "config/lua")) {
    g_autoptr (WpCore) core = wp_object_get_core (WP_OBJECT (cl));
    return wp_lua_scripting_load_configuration (component, core, error);
  }

  g_return_val_if_reached (FALSE);
}

static void
wp_lua_scripting_plugin_class_init (WpLuaScriptingPluginClass * klass)
{
  GObjectClass *object_class = (GObjectClass *) klass;
  WpPluginClass *plugin_class = (WpPluginClass *) klass;
  WpComponentLoaderClass *cl_class = (WpComponentLoaderClass *) klass;

  object_class->finalize = wp_lua_scripting_plugin_finalize;

  plugin_class->enable = wp_lua_scripting_plugin_enable;
  plugin_class->disable = wp_lua_scripting_plugin_disable;

  cl_class->supports_type = wp_lua_scripting_plugin_supports_type;
  cl_class->load = wp_lua_scripting_plugin_load;
}

WP_PLUGIN_EXPORT gboolean
wireplumber__module_init (WpCore * core, GVariant * args, GError ** error)
{
  wp_plugin_register (g_object_new (wp_lua_scripting_plugin_get_type (),
          "name", "lua-scripting",
          "core", core,
          NULL));
  return TRUE;
}