Cthulhu is no longer a fork. Now it is a screen reader written in Golang.

internal/atspi/adapter_position.c

@@ -0,0 +1,127 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "adapter_native.h"
+
+gboolean cthulhu_has_set_position(const gchar *role) {
+    return g_strcmp0(role, "list item") == 0 || g_strcmp0(role, "tree item") == 0 ||
+           g_strcmp0(role, "menu item") == 0 || g_strcmp0(role, "check menu item") == 0 ||
+           g_strcmp0(role, "radio menu item") == 0 || g_strcmp0(role, "page tab") == 0 ||
+           g_strcmp0(role, "radio button") == 0;
+}
+
+static gint cthulhu_positive_integer(const gchar *value) {
+    if (value == NULL || *value < '0' || *value > '9') return 0;
+    gchar *end = NULL;
+    gint64 number = g_ascii_strtoll(value, &end, 10);
+    if (*end != '\0' || number <= 0 || number > G_MAXINT) return 0;
+    return (gint)number;
+}
+
+static gboolean cthulhu_menu_item(AtspiRole role) {
+    return role == ATSPI_ROLE_MENU_ITEM || role == ATSPI_ROLE_CHECK_MENU_ITEM ||
+           role == ATSPI_ROLE_RADIO_MENU_ITEM;
+}
+
+static gboolean cthulhu_group_member(AtspiRelation *relation, AtspiAccessible *child) {
+    for (gint index = 0; index < atspi_relation_get_n_targets(relation); index++) {
+        AtspiAccessible *target = atspi_relation_get_target(relation, index);
+        gboolean matches = target != NULL &&
+            g_strcmp0(cthulhu_accessible_bus_name(target), cthulhu_accessible_bus_name(child)) == 0 &&
+            g_strcmp0(cthulhu_accessible_path(target), cthulhu_accessible_path(child)) == 0;
+        if (target != NULL) g_object_unref(target);
+        if (matches) return TRUE;
+    }
+    return FALSE;
+}
+
+void cthulhu_capture_set_position(AtspiAccessible *source, GHashTable *attributes,
+                                  cthulhu_snapshot *snapshot) {
+    const gchar *position = attributes == NULL ? NULL : g_hash_table_lookup(attributes, "posinset");
+    const gchar *size = attributes == NULL ? NULL : g_hash_table_lookup(attributes, "setsize");
+    // Explicit provider values describe virtualized and hierarchical sets.
+    // Partial, unknown (-1), or invalid values must not become sibling guesses.
+    if (position != NULL || size != NULL) {
+        gint parsedPosition = cthulhu_positive_integer(position);
+        gint parsedSize = cthulhu_positive_integer(size);
+        if (parsedPosition > 0 && parsedPosition <= parsedSize) {
+            snapshot->positionInSet = parsedPosition;
+            snapshot->setSize = parsedSize;
+        }
+        return;
+    }
+    GError *error = NULL;
+    AtspiAccessible *parent = atspi_accessible_get_parent(source, &error);
+    if (error != NULL || parent == NULL) {
+        g_clear_error(&error);
+        if (parent != NULL) g_object_unref(parent);
+        return;
+    }
+    AtspiRole sourceRole = atspi_accessible_get_role(source, &error);
+    GArray *relations = NULL;
+    AtspiRelation *memberRelation = NULL;
+    if (error != NULL) goto cleanup;
+    if (sourceRole == ATSPI_ROLE_RADIO_BUTTON) {
+        relations = atspi_accessible_get_relation_set(source, &error);
+        if (error != NULL) goto cleanup;
+        for (guint index = 0; relations != NULL && index < relations->len; index++) {
+            AtspiRelation *relation = g_array_index(relations, AtspiRelation *, index);
+            if (atspi_relation_get_relation_type(relation) == ATSPI_RELATION_MEMBER_OF) {
+                memberRelation = relation;
+                if (atspi_relation_get_n_targets(relation) > 128) goto cleanup;
+                break;
+            }
+        }
+    }
+    AtspiRole parentRole = atspi_accessible_get_role(parent, &error);
+    if (error != NULL) goto cleanup;
+    // A flattened tree does not reliably describe logical sibling sets.
+    if (sourceRole == ATSPI_ROLE_TREE_ITEM) goto cleanup;
+    if (sourceRole == ATSPI_ROLE_LIST_ITEM && parentRole != ATSPI_ROLE_LIST && parentRole != ATSPI_ROLE_LIST_BOX)
+        goto cleanup;
+    if (sourceRole == ATSPI_ROLE_PAGE_TAB && parentRole != ATSPI_ROLE_PAGE_TAB_LIST) goto cleanup;
+    if (cthulhu_menu_item(sourceRole) && parentRole != ATSPI_ROLE_MENU && parentRole != ATSPI_ROLE_MENU_BAR)
+        goto cleanup;
+    gint count = atspi_accessible_get_child_count(parent, &error);
+    if (error != NULL) goto cleanup;
+    if (count <= 0) goto cleanup;
+    gint index = atspi_accessible_get_index_in_parent(source, &error);
+    if (error != NULL || index < 0 || index >= count) goto cleanup;
+    // Lists and tab lists expose their items in child order, including large
+    // sets. This uses a fixed number of queries rather than a sibling walk.
+    if (sourceRole == ATSPI_ROLE_LIST_ITEM || sourceRole == ATSPI_ROLE_PAGE_TAB) {
+        snapshot->positionInSet = index + 1;
+        snapshot->setSize = count;
+        goto cleanup;
+    }
+    // Menus contain separators; radio containers can contain labels and
+    // unrelated controls. Count only item peers, with bounded native work.
+    if (count > 128) goto cleanup;
+    gint itemPosition = 0, setSize = 0;
+    for (gint childIndex = 0; childIndex < count; childIndex++) {
+        AtspiAccessible *child = atspi_accessible_get_child_at_index(parent, childIndex, &error);
+        if (error != NULL || child == NULL) {
+            if (child != NULL) g_object_unref(child);
+            goto cleanup;
+        }
+        AtspiRole childRole = atspi_accessible_get_role(child, &error);
+        gboolean member = memberRelation == NULL || cthulhu_group_member(memberRelation, child);
+        g_object_unref(child);
+        if (error != NULL) goto cleanup;
+        if (!member) continue;
+        if (childRole != sourceRole && !(cthulhu_menu_item(sourceRole) && cthulhu_menu_item(childRole))) continue;
+        setSize++;
+        if (childIndex == index) itemPosition = setSize;
+    }
+    snapshot->positionInSet = itemPosition;
+    snapshot->setSize = setSize;
+cleanup:
+    if (relations != NULL) {
+        for (guint index = 0; index < relations->len; index++)
+            g_object_unref(g_array_index(relations, AtspiRelation *, index));
+        g_array_unref(relations);
+    }
+    g_clear_error(&error);
+    g_object_unref(parent);
+}