fbd-feedback-manager: Allow device-specific feedbackd themes

Reads the compatible list of the device and tries to find a device-specific theme file in all  directories. If no configuration is found, we fall back to a default theme file. The device-specific theme file can always be overriden by specifying the FEEDBACK_THEME environment variable

src/fbd-feedback-manager.c

@@ -21,10 +21,14 @@
 
 #define FEEDBACKD_SCHEMA_ID "org.sigxcpu.feedbackd"
 #define FEEDBACKD_KEY_PROFILE "profile"
+#define FEEDBACKD_THEME_VAR "FEEDBACK_THEME"
 
 #define APP_SCHEMA FEEDBACKD_SCHEMA_ID ".application"
 #define APP_PREFIX "/org/sigxcpu/feedbackd/application/"
 
+#define DEVICE_TREE_PATH "/sys/firmware/devicetree/base/compatible"
+#define DEVICE_NAME_MAX 1024
+
 
 /**
  * SECTION:fbd-feedback-manager
@@ -352,6 +356,51 @@ fbd_feedback_manager_handle_end_feedback (LfbGdbusFeedback *object,
   return TRUE;
 }
 
+static const gchar *
+find_themefile (void) {
+  gint i = 0;
+  gsize len;
+  const gchar *comp;
+  g_autoptr(GError) err = NULL;
+  gchar **xdg_data_dirs = (gchar **) g_get_system_data_dirs();
+  g_autofree gchar *config_path = NULL;
+  g_autofree gchar *compatibles = NULL;
+
+  // Try to read the device name
+  if (g_file_test(DEVICE_TREE_PATH, (G_FILE_TEST_EXISTS))) {
+    g_debug("Found device tree device compatible at %s", DEVICE_TREE_PATH);
+
+    // Check if feedbackd has a proper config available this device
+    if(!g_file_get_contents(DEVICE_TREE_PATH, &compatibles, &len, &err))
+      g_warning ("Unable to read: %s", err->message);
+
+    comp = compatibles;
+    while(comp - compatibles < len) {
+
+      // Iterate over $XDG_DATA_DIRS
+      for (i = 0; i < g_strv_length(xdg_data_dirs); i++) {
+        config_path = g_strconcat(xdg_data_dirs[i], "feedbackd/themes/", comp, ".json", NULL);
+        g_debug("Searching for device specific themefile in %s", config_path);
+
+        // Check if file exist
+        if (g_file_test(config_path, (G_FILE_TEST_EXISTS))) {
+          g_debug("Found themefile for this device at: %s", config_path);
+	  return g_strdup(config_path);
+        }
+      }
+
+      // Next compatible
+      comp = strchr(comp, 0);
+      comp++;
+    }
+  }
+  else {
+    g_debug("Device tree path does not exist: %s", DEVICE_TREE_PATH);
+  }
+
+  return NULL;
+}
+
 static void
 fbd_feedback_manager_constructed (GObject *object)
 {
@@ -361,14 +410,22 @@ fbd_feedback_manager_constructed (GObject *object)
 
   G_OBJECT_CLASS (fbd_feedback_manager_parent_class)->constructed (object);
 
-  themefile = g_getenv ("FEEDBACK_THEME");
+  // Overide themefile with environment variable if requested
+  themefile = g_getenv(FEEDBACKD_THEME_VAR);
+
+  // Search for device-specific configuration
+  if (!themefile)
+    themefile = find_themefile ();
+
+  // Fallback to default configuration if needed
   if (!themefile)
     themefile = FEEDBACKD_THEME_DIR "/default.json";
+  g_info("Using themefile: %s", themefile);
 
   self->theme = fbd_feedback_theme_new_from_file (themefile, &err);
   if (!self->theme) {
     /* No point to carry on */
-    g_error ("Failed to load default theme: %s", err->message);
+    g_error ("Failed to load theme: %s", err->message);
   }
 
   g_signal_connect (self, "notify::profile", (GCallback)on_profile_changed, NULL);