m-session-settings: implement storing and loading default endpoint user settings

modules/module-session-settings.c

@@ -6,12 +6,23 @@
  * SPDX-License-Identifier: MIT
  */
 
+/*
+ * This module selects "default" source & sink endpoints for each session
+ * and when the user modifies them, it stores the user preference in text
+ * files in $XDG_CONFIG_DIR, similarly to pulseaudio
+ */
+
 #include <wp/wp.h>
+#include <errno.h>
+
+G_DEFINE_QUARK (wp-session-settings-sink-file, session_settings_sink_file)
+G_DEFINE_QUARK (wp-session-settings-source-file, session_settings_source_file)
 
 struct _WpSessionSettings
 {
   WpPlugin parent;
   WpObjectManager *sessions_om;
+  gchar *config_dir;
 };
 
 G_DECLARE_FINAL_TYPE (WpSessionSettings, wp_session_settings,
@@ -21,6 +32,63 @@ G_DEFINE_TYPE (WpSessionSettings, wp_session_settings, WP_TYPE_PLUGIN)
 static void
 wp_session_settings_init (WpSessionSettings * self)
 {
+  self->config_dir = g_build_filename (g_get_user_config_dir (),
+      "wireplumber", NULL);
+  if (g_mkdir_with_parents (self->config_dir, 0755) < 0) {
+    wp_warning_object (self, "failed to create '%s': %s", self->config_dir,
+        strerror (errno));
+  }
+}
+
+static void
+wp_session_settings_finalize (GObject * object)
+{
+  WpSessionSettings * self = WP_SESSION_SETTINGS (object);
+
+  g_free (self->config_dir);
+
+  G_OBJECT_CLASS (wp_session_settings_parent_class)->finalize (object);
+}
+
+static void
+on_default_endpoint_changed (WpSession * session, const gchar * type,
+    guint32 id, WpSessionSettings * self)
+{
+  GFile *file = NULL;
+  g_autoptr (GFileOutputStream) out_stream = NULL;
+  g_autoptr (GError) error = NULL;
+  g_autoptr (WpEndpoint) ep = NULL;
+
+  wp_debug_object (self, "%s on " WP_OBJECT_FORMAT " changed (%u), storing",
+      type, WP_OBJECT_ARGS (session), id);
+
+  if (g_strcmp0 (type, "Wp:defaultSink") == 0)
+    file = g_object_get_qdata (G_OBJECT (session),
+        session_settings_sink_file_quark ());
+  else if (g_strcmp0 (type, "Wp:defaultSource") == 0)
+    file = g_object_get_qdata (G_OBJECT (session),
+        session_settings_source_file_quark ());
+  g_return_if_fail (file);
+
+  ep = wp_session_lookup_endpoint (session,
+      WP_CONSTRAINT_TYPE_G_PROPERTY, "bound-id", "=u", id, NULL);
+  if (!ep) {
+    wp_warning_object (self, "%s (%u) on " WP_OBJECT_FORMAT " not found",
+        type, id, WP_OBJECT_ARGS (session));
+    return;
+  }
+
+  out_stream = g_file_replace (file, NULL, FALSE, G_FILE_CREATE_NONE, NULL,
+      &error);
+  if (out_stream) {
+    /* write the name plus its terminating null byte */
+    const gchar *name = wp_endpoint_get_name (ep);
+    if (!g_output_stream_write_all (G_OUTPUT_STREAM (out_stream),
+            name, strlen (name) + 1, NULL, NULL, &error)) {
+      wp_warning_object (self, "error writing %s: %s", g_file_peek_path (file),
+          error->message);
+    }
+  }
 }
 
 static guint32
@@ -54,36 +122,102 @@ find_highest_prio (WpSession * session, WpDirection dir)
 }
 
 static void
-reevaluate_defaults (WpSession * session, WpDirection dir)
+reevaluate_defaults (WpSessionSettings * self,
+    WpSession * session, WpDirection dir)
 {
   guint32 id = 0;
+  GFile *file;
+  g_autoptr (GFileInputStream) in_stream = NULL;
+  g_autoptr (GError) error = NULL;
+  gchar buffer[128];
+
+  /* try to read the default endpoint's name from the settings file */
+
+  file = g_object_get_qdata (G_OBJECT (session),
+      (dir == WP_DIRECTION_INPUT) ?
+      session_settings_sink_file_quark () :
+      session_settings_source_file_quark ());
 
-  /* TODO
-  if (settings exist)
-    id = lookup endpoint in settings
-  */
+  in_stream = g_file_read (file, NULL, &error);
+  if (in_stream) {
+    gsize bytes_read = 0;
+    g_autoptr (WpEndpoint) ep = NULL;
+
+    if (!g_input_stream_read_all (G_INPUT_STREAM (in_stream), buffer,
+            sizeof (buffer), &bytes_read, NULL, &error)) {
+      wp_warning_object (self, "error reading %s: %s", g_file_peek_path (file),
+          error->message);
+    } else {
+      /* the file should have a null byte, but let's not trust it */
+      buffer[MIN (bytes_read, sizeof (buffer) - 1)] = '\0';
+      ep = wp_session_lookup_endpoint (session,
+          WP_CONSTRAINT_TYPE_PW_PROPERTY, "endpoint.name", "=s", buffer,
+          WP_CONSTRAINT_TYPE_PW_PROPERTY, "media.class", "#s",
+              (dir == WP_DIRECTION_INPUT) ? "*/Sink" : "*/Source",
+          NULL);
+      if (ep)
+        id = wp_proxy_get_bound_id (WP_PROXY (ep));
+    }
+  }
+  else if (error) {
+    /* this is an expected condition if no settings are stored; just debug */
+    wp_debug_object (self, "file read error (%s): %s", g_file_peek_path (file),
+        error->message);
+  }
 
+  /* if not found by settings, find the highest priority one */
   if (id == 0)
     id = find_highest_prio (session, dir);
 
+  wp_debug_object (self, "selecting default %s for " WP_OBJECT_FORMAT ": %u",
+      (dir == WP_DIRECTION_INPUT) ? "sink" : "source",
+      WP_OBJECT_ARGS (session), id);
+
+  /* block the signal to avoid storing this on the file;
+     only selections done by the user should be stored */
+  g_signal_handlers_block_by_func (session, on_default_endpoint_changed, self);
   wp_session_set_default_endpoint (session,
       (dir == WP_DIRECTION_INPUT) ? "Wp:defaultSink" : "Wp:defaultSource", id);
+  g_signal_handlers_unblock_by_func (session, on_default_endpoint_changed, self);
 }
 
 static void
 on_endpoints_changed (WpSession * session, WpSessionSettings * self)
 {
-  reevaluate_defaults (session, WP_DIRECTION_INPUT);
-  reevaluate_defaults (session, WP_DIRECTION_OUTPUT);
+  wp_trace_object (session, "endpoints changed, re-evaluating defaults");
+  reevaluate_defaults (self, session, WP_DIRECTION_INPUT);
+  reevaluate_defaults (self, session, WP_DIRECTION_OUTPUT);
 }
 
 static void
 on_session_added (WpObjectManager * om, WpSession * session,
     WpSessionSettings * self)
 {
-  on_endpoints_changed (session, self);
+  GFile *sink_file;
+  GFile *source_file;
+  gchar *filename;
+
+  filename = g_strdup_printf ("%s%c%s-default-sink", self->config_dir,
+      G_DIR_SEPARATOR, wp_session_get_name (session));
+  sink_file = g_file_new_for_path (filename);
+  g_free (filename);
+
+  filename = g_strdup_printf ("%s%c%s-default-source", self->config_dir,
+      G_DIR_SEPARATOR, wp_session_get_name (session));
+  source_file = g_file_new_for_path (filename);
+  g_free (filename);
+
+  g_object_set_qdata_full (G_OBJECT (session),
+      session_settings_sink_file_quark (), sink_file, g_object_unref);
+  g_object_set_qdata_full (G_OBJECT (session),
+      session_settings_source_file_quark (), source_file, g_object_unref);
+
+  g_signal_connect_object (session, "default-endpoint-changed",
+      G_CALLBACK (on_default_endpoint_changed), self, 0);
   g_signal_connect_object (session, "endpoints-changed",
       G_CALLBACK (on_endpoints_changed), self, 0);
+
+  on_endpoints_changed (session, self);
 }
 
 static void
@@ -116,8 +250,11 @@ wp_session_settings_deactivate (WpPlugin * plugin)
 static void
 wp_session_settings_class_init (WpSessionSettingsClass * klass)
 {
+  GObjectClass *object_class = (GObjectClass *) klass;
   WpPluginClass *plugin_class = (WpPluginClass *) klass;
 
+  object_class->finalize = wp_session_settings_finalize;
+
   plugin_class->activate = wp_session_settings_activate;
   plugin_class->deactivate = wp_session_settings_deactivate;
 }