Filter out stale accessibility events.

internal/atspi/adapter_event_queue.c

@@ -0,0 +1,90 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "adapter_native.h"
+
+extern void cthulhuAtspiSelectionCallback(AtspiEvent *event, void *userData, uint64_t epoch);
+
+// This check uses only libatspi's cache. Unknown metadata retains the normal
+// query path; a stale non-FOCUSED state alone never rejects an explicit claim.
+gboolean cthulhu_accessible_known_dead(AtspiAccessible *source) {
+    if (source == NULL) return TRUE;
+    if (source->states != NULL && atspi_state_set_contains(source->states, ATSPI_STATE_DEFUNCT)) return TRUE;
+    return (source->cached_properties & ATSPI_CACHE_ROLE) && source->role == ATSPI_ROLE_INVALID;
+}
+
+gboolean cthulhu_gtk_table(AtspiAccessible *source, gboolean queryToolkit) {
+    if (source == NULL || !(source->cached_properties & ATSPI_CACHE_ROLE)) return FALSE;
+    if (source->role != ATSPI_ROLE_TABLE && source->role != ATSPI_ROLE_TREE_TABLE &&
+        source->role != ATSPI_ROLE_LIST && source->role != ATSPI_ROLE_TREE) return FALSE;
+    AtspiApplication *application = ATSPI_OBJECT(source)->app;
+    // libatspi caches toolkit identity per application. Seed that cache on
+    // the first table selection if focus capture has not needed it yet.
+    if (queryToolkit && application != NULL && application->toolkit_name == NULL) {
+        gchar *toolkit = atspi_accessible_get_toolkit_name(source, NULL);
+        g_free(toolkit);
+    }
+    if (application == NULL || g_ascii_strcasecmp(application->toolkit_name != NULL ? application->toolkit_name : "", "gtk") != 0) return FALSE;
+    if (source->role == ATSPI_ROLE_TABLE || source->role == ATSPI_ROLE_TREE_TABLE) return TRUE;
+    if ((source->role != ATSPI_ROLE_LIST && source->role != ATSPI_ROLE_TREE) ||
+        !(source->cached_properties & ATSPI_CACHE_INTERFACES)) return FALSE;
+    AtspiTable *table = atspi_accessible_get_table_iface(source);
+    if (table == NULL) return FALSE;
+    g_object_unref(table);
+    return TRUE;
+}
+
+// All queue state and boxed events belong exclusively to the GLib owner.
+// Only one table can be pending. A different table or another live event
+// flushes it first, preserving ordering across focus/lifecycle boundaries.
+void cthulhu_flush_selection(cthulhu_callback_data *data) {
+    if (data->selectionIdle != 0) {
+        g_source_remove(data->selectionIdle);
+        data->selectionIdle = 0;
+    }
+    AtspiEvent *event = data->pendingSelection;
+    uint64_t epoch = data->selectionEpoch;
+    data->pendingSelection = NULL;
+    if (event == NULL) return;
+    cthulhuAtspiSelectionCallback(event, data, epoch);
+    g_boxed_free(ATSPI_TYPE_EVENT, event);
+}
+
+void cthulhu_flush_other_selection(cthulhu_callback_data *data, AtspiAccessible *source) {
+    if (data->pendingSelection != NULL && data->pendingSelection->source != source) {
+        cthulhu_flush_selection(data);
+    }
+}
+
+static gboolean cthulhu_selection_idle(gpointer userData) {
+    cthulhu_callback_data *data = userData;
+    data->selectionIdle = 0;
+    cthulhu_flush_selection(data);
+    return G_SOURCE_REMOVE;
+}
+
+void cthulhu_defer_selection(cthulhu_callback_data *data, AtspiEvent *event, uint64_t epoch) {
+    cthulhu_flush_other_selection(data, event->source);
+    if (data->pendingSelection != NULL) g_boxed_free(ATSPI_TYPE_EVENT, data->pendingSelection);
+    data->pendingSelection = g_boxed_copy(ATSPI_TYPE_EVENT, event);
+    data->selectionEpoch = epoch;
+    if (data->selectionIdle == 0) {
+        // No timer/debounce delay: read the latest selection when the ready
+        // provider signals have drained. Ordinary arrows still flush on their
+        // following live focus/descendant event, or at the next idle turn.
+        data->selectionIdle = g_idle_add(cthulhu_selection_idle, data);
+    }
+}
+
+void cthulhu_clear_selection(cthulhu_callback_data *data) {
+    if (data == NULL) return;
+    if (data->selectionIdle != 0) {
+        g_source_remove(data->selectionIdle);
+        data->selectionIdle = 0;
+    }
+    if (data->pendingSelection != NULL) {
+        g_boxed_free(ATSPI_TYPE_EVENT, data->pendingSelection);
+        data->pendingSelection = NULL;
+    }
+}