simple-policy: add new module

modules/meson.build

@@ -39,3 +39,14 @@ shared_library(
   install_dir : wireplumber_module_dir,
   dependencies : [wp_dep, pipewire_dep],
 )
+
+shared_library(
+  'wireplumber-module-pw-simple-policy',
+  [
+    'module-pw-simple-policy.c'
+  ],
+  c_args : [common_c_args, '-DG_LOG_DOMAIN="m-pw-simple-policy"'],
+  install : true,
+  install_dir : wireplumber_module_dir,
+  dependencies : [wp_dep, pipewire_dep],
+)

modules/module-pw-simple-policy.c

+/* WirePlumber
+ *
+ * Copyright © 2019 Collabora Ltd.
+ *    @author Julian Bouzas <julian.bouzas@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/**
+ * module-pw-simple-policy connects the first audio output client endpoint with
+ * the first audio sink remote endpoint
+ */
+
+#include <wp/wp.h>
+#include <pipewire/pipewire.h>
+
+typedef void (*WpDoneCallback)(gpointer);
+
+struct impl {
+  WpCore *wp_core;
+
+  /* Remote */
+  struct pw_remote *remote;
+  struct spa_hook remote_listener;
+
+  /* Core */
+  struct pw_core_proxy *core_proxy;
+  struct spa_hook core_listener;
+  int core_seq;
+  WpDoneCallback done_cb;
+  gpointer done_cb_data;
+
+  /* Endpoints */
+  WpEndpoint *ep_client;
+  WpEndpoint *ep_remote;
+};
+
+static void sync_core_with_callabck(struct impl* impl, WpDoneCallback callback,
+    gpointer data) {
+  /* Set the callback and data */
+  impl->done_cb = callback;
+  impl->done_cb_data = data;
+
+  /* Sync the core */
+  impl->core_seq = pw_core_proxy_sync(impl->core_proxy, 0, impl->core_seq);
+}
+
+static void endpoint_first_foreach(WpEndpoint *ep, WpEndpoint **first)
+{
+  /* Just return if first is already set */
+  if (*first)
+    return;
+
+  /* Set first to the current endpoint */
+  *first = g_object_ref(ep);
+}
+
+static WpEndpoint *endpoint_get_first(WpCore *core,
+    const char *media_class)
+{
+  WpEndpoint *first = NULL;
+  GPtrArray *ptr_array = NULL;
+
+  /* Get all the endpoints with the specific media lcass*/
+  ptr_array = wp_endpoint_find (core, media_class);
+  if (!ptr_array)
+    return NULL;
+
+  /* Get the first endpoint of the list */
+  g_ptr_array_foreach(ptr_array, (GFunc)endpoint_first_foreach, &first);
+
+  /* Return the first endpoint */
+  return first;
+}
+
+static void link_endpoints(gpointer data) {
+  struct impl *impl = data;
+  WpEndpointLink *ep_link = NULL;
+
+  /* Make sure the endpoints are valid */
+  if (!impl->ep_client || !impl->ep_remote) {
+    g_warning ("Endpoints not valid to link. Skipping...\n");
+    return;
+  }
+
+  /* Link the client with the remote */
+  ep_link = wp_endpoint_link_new(impl->wp_core, impl->ep_client, 0,
+      impl->ep_remote, 0, NULL);
+  if (!ep_link) {
+    g_warning ("Could not link endpoints. Skipping...\n");
+    return;
+  }
+
+  g_info ("Endpoints linked successfully\n");
+}
+
+static void
+endpoint_added (WpCore *core, GQuark key, WpEndpoint *ep, struct impl * impl)
+{
+  const char *media_class = NULL;
+
+  /* Reset endpoints */
+  impl->ep_remote = NULL;
+  impl->ep_client = NULL;
+
+  /* Make sure an endpoint has been added */
+  g_return_if_fail (key == WP_GLOBAL_ENDPOINT);
+
+  /* Get the media class */
+  media_class = wp_endpoint_get_media_class(ep);
+
+  /* Only process client endpoints */
+  if (!g_str_has_prefix(media_class, "Stream"))
+    return;
+
+  /* TODO: For now we only accept audio output clients */
+  if (!g_str_has_prefix(media_class, "Stream/Output/Audio"))
+    return;
+  impl->ep_client = ep;
+
+  /* Get the first endpoint with media class Audio/Sink */
+  impl->ep_remote = endpoint_get_first(core, "Audio/Sink");
+  if (!impl->ep_remote) {
+    g_warning ("Could not get an Audio/Sink remote endpoint\n");
+    return;
+  }
+
+  /* Do the linking when core is done */
+  sync_core_with_callabck (impl, link_endpoints, impl);
+}
+
+static void core_done(void *data, uint32_t id, int seq)
+{
+  struct impl * impl = data;
+
+  /* Call the done callback if it exists */
+  if (impl->done_cb)
+    impl->done_cb(impl->done_cb_data);
+
+  impl->done_cb = NULL;
+  impl->done_cb_data = NULL;
+}
+
+static const struct pw_core_proxy_events core_events = {
+  PW_VERSION_CORE_EVENTS,
+  .done = core_done
+};
+
+static void on_state_changed(void *_data, enum pw_remote_state old,
+    enum pw_remote_state state, const char *error)
+{
+  struct impl *impl = _data;
+
+  switch (state) {
+  case PW_REMOTE_STATE_ERROR:
+          break;
+
+  case PW_REMOTE_STATE_CONNECTED:
+          /* Register the core event callbacks */
+          impl->core_proxy = pw_remote_get_core_proxy(impl->remote);
+          pw_core_proxy_add_listener(impl->core_proxy, &impl->core_listener,
+              &core_events, impl);
+          break;
+
+  case PW_REMOTE_STATE_UNCONNECTED:
+          break;
+
+  default:
+          break;
+  }
+}
+
+static const struct pw_remote_events remote_events = {
+  PW_VERSION_REMOTE_EVENTS,
+  .state_changed = on_state_changed,
+};
+
+static void
+module_destroy (gpointer data)
+{
+  struct impl *impl = data;
+  g_slice_free (struct impl, impl);
+}
+
+void
+wireplumber__module_init (WpModule * module, WpCore * core, GVariant * args)
+{
+  struct impl *impl = g_new0(struct impl, 1);
+
+  /* Set destroy callback for impl */
+  wp_module_set_destroy_callback (module, module_destroy, impl);
+
+  /* Set the core */
+  impl->wp_core = core;
+
+  /* Set the core remote */
+  impl->remote = wp_core_get_global(core, WP_GLOBAL_PW_REMOTE);
+
+  /* Add a state changed listener */
+  pw_remote_add_listener(impl->remote, &impl->remote_listener, &remote_events,
+      impl);
+
+  /* Register the endpoint added and removed callbacks */
+  g_signal_connect (core, "global-added::endpoint",
+    (GCallback) endpoint_added, impl);
+}

src/wireplumber.conf

 load-module C libwireplumber-module-pipewire
 load-module C libwireplumber-module-pw-audio-softdsp-endpoint
 load-module C libwireplumber-module-pw-alsa-udev
+load-module C libwireplumber-module-pw-simple-policy