Refactor the API for the screen reader to notify listeners of its status

Remove atspi_text_notify_reading_position, and instead add a region_changed
signal. Also make the dbus API more like the API used for other events.

Per discussion at https://gitlab.gnome.org/GNOME/orca/issues/36

1 files changed, 83 insertions, 0 deletions

diff --git a/atspi/atspi-accessible.c b/atspi/atspi-accessible.c
index 2a0eda10..b2f26915 100644
--- a/atspi/atspi-accessible.c
+++ b/atspi/atspi-accessible.c
@@ -26,9 +26,63 @@
 #include "atspi-accessible-private.h"
 #include <string.h>
 
+enum {
+  REGION_CHANGED,
+  LAST_SIGNAL
+};
+
 static gboolean enable_caching = FALSE;
 static guint quark_locale;
 
+static guint atspi_accessible_signals[LAST_SIGNAL] = { 0, };
+
+static gboolean
+screen_reader_signal_watcher (GSignalInvocationHint *signal_hint,
+                              guint                  n_param_values,
+                              const GValue          *param_values,
+                              gpointer               data)
+{
+  GObject *object;
+  AtspiAccessible *accessible;
+  GSignalQuery signal_query;
+  const char *name;
+  DBusMessage *signal;
+  DBusMessageIter iter, iter_struct, iter_variant, iter_array;
+  dbus_int32_t detail1, detail2;
+  const char *detail = "";
+
+  object = g_value_get_object (param_values + 0);
+  g_return_val_if_fail (ATSPI_IS_ACCESSIBLE(object), FALSE);
+
+  g_signal_query (signal_hint->signal_id, &signal_query);
+  name = signal_query.signal_name;
+  detail1 = g_value_get_int (param_values + 1);
+  detail2 = g_value_get_int (param_values + 2);
+  accessible = ATSPI_ACCESSIBLE (object);
+
+  signal = dbus_message_new_signal (ATSPI_DBUS_PATH_SCREEN_READER,
+                                    ATSPI_DBUS_INTERFACE_EVENT_SCREEN_READER,
+                                    "RegionChanged");
+  dbus_message_iter_init_append (signal, &iter);
+  dbus_message_iter_append_basic (&iter, DBUS_TYPE_STRING, &detail);
+  dbus_message_iter_append_basic (&iter, DBUS_TYPE_INT32, &detail1);
+  dbus_message_iter_append_basic (&iter, DBUS_TYPE_INT32, &detail2);
+  dbus_message_iter_open_container (&iter, DBUS_TYPE_VARIANT, "(so)",
+                                    &iter_variant);
+  dbus_message_iter_open_container (&iter_variant, DBUS_TYPE_STRUCT, NULL,
+                                    &iter_struct);
+  dbus_message_iter_append_basic (&iter_struct, DBUS_TYPE_STRING, &accessible->parent.app->bus_name);
+  dbus_message_iter_append_basic (&iter_struct, DBUS_TYPE_OBJECT_PATH, &accessible->parent.path);
+  dbus_message_iter_close_container (&iter_variant, &iter_struct);
+  dbus_message_iter_close_container (&iter, &iter_variant);
+  dbus_message_iter_open_container (&iter, DBUS_TYPE_ARRAY, "{sv}",
+                                    &iter_array);
+  dbus_message_iter_close_container (&iter, &iter_array);
+  dbus_connection_send (_atspi_bus (), signal, NULL);
+  dbus_message_unref (signal);
+  return TRUE; 
+}
+
 static void
 atspi_action_interface_init (AtspiAction *action)
 {
@@ -189,6 +243,8 @@ atspi_accessible_finalize (GObject *object)
 #endif
 
   G_OBJECT_CLASS (atspi_accessible_parent_class)->finalize (object);
+
+  /* TODO: remove emission hook */
 }
 
 static void
@@ -200,6 +256,33 @@ atspi_accessible_class_init (AtspiAccessibleClass *klass)
   object_class->finalize = atspi_accessible_finalize;
 
   quark_locale = g_quark_from_string ("accessible-locale");
+
+  /**
+   * AtspiAccessible::region-changed:
+   * @atspiaccessible: the object which received the signal
+   * @arg1: an integer specifying the current offset of the text being read,
+   *        if the object is textual.
+   * @arg2: an integer specifying the ending offset of the text being read,
+   *        if the object is textual.
+   *
+   * The signal "region-changed" is emitted by a screen reader to inndicate
+   * that it is now reading or tracking a new object, or, a new piece of
+   * text within an object. This allows a magnifier to gain the information
+   * needded to highlight the object that the screen reader is reading.
+   */
+  atspi_accessible_signals[REGION_CHANGED] =
+    g_signal_new ("region_changed",
+		  G_TYPE_FROM_CLASS (klass),
+		  G_SIGNAL_RUN_LAST,
+		  G_STRUCT_OFFSET (AtspiAccessibleClass, region_changed), 
+		  NULL, NULL,
+		  atspi_marshal_VOID__INT_INT,
+		  G_TYPE_NONE,
+		  2, G_TYPE_INT, G_TYPE_INT);
+
+  g_signal_add_emission_hook (atspi_accessible_signals[REGION_CHANGED], 0,
+                              screen_reader_signal_watcher, NULL,
+                              (GDestroyNotify) NULL);
 }
 
 /**