[evolution/gnome-3-34] I#624 - GalA11yETableItem: Incorrect implementation of AtkObjectClass::ref_child()

[Milan Crha <mcrha src gnome org>]

commit f5857563b383882fd55d8a04614a417484263f5c
Author: Milan Crha <mcrha redhat com>
Date:   Wed Sep 18 14:12:44 2019 +0200

    I#624 - GalA11yETableItem: Incorrect implementation of AtkObjectClass::ref_child()
    
    Closes https://gitlab.gnome.org/GNOME/evolution/issues/624

 src/e-util/gal-a11y-e-table-item.c | 106 +++++++++++++++++++++++++++++++++++--
 1 file changed, 102 insertions(+), 4 deletions(-)
---
diff --git a/src/e-util/gal-a11y-e-table-item.c b/src/e-util/gal-a11y-e-table-item.c
index cf06fb3f4f..be302ed09d 100644
--- a/src/e-util/gal-a11y-e-table-item.c
+++ b/src/e-util/gal-a11y-e-table-item.c
@@ -61,6 +61,7 @@ struct _GalA11yETableItemPrivate {
        ESelectionModel *selection;
        AtkStateSet *state_set;
        GtkWidget *widget;
+       GHashTable *a11y_column_headers; /* ETableCol * ~> GalA11yETableColumnHeader * */
 };
 
 static gboolean gal_a11y_e_table_item_ref_selection (GalA11yETableItem *a11y,
@@ -124,6 +125,11 @@ item_finalized (gpointer user_data,
        if (priv->selection)
                gal_a11y_e_table_item_unref_selection (a11y);
 
+       if (priv->columns) {
+               free_columns (priv->columns);
+               priv->columns = NULL;
+       }
+
        g_object_unref (a11y);
 }
 
@@ -273,11 +279,60 @@ eti_a11y_reset_focus_object (GalA11yETableItem *a11y,
                g_signal_emit_by_name (a11y, "active-descendant-changed", cell);
 }
 
+static void eti_column_header_a11y_gone (gpointer user_data, GObject *a11y_col_header);
+
+static void
+eti_table_column_gone (gpointer user_data,
+                      GObject *col)
+{
+       GalA11yETableItem *a11y = user_data;
+       GalA11yETableItemPrivate *priv;
+       GalA11yETableColumnHeader *a11y_col_header;
+
+       g_return_if_fail (GAL_A11Y_IS_E_TABLE_ITEM (a11y));
+
+       priv = GET_PRIVATE (a11y);
+
+       a11y_col_header = g_hash_table_lookup (priv->a11y_column_headers, col);
+       g_hash_table_remove (priv->a11y_column_headers, col);
+
+       if (a11y_col_header)
+               g_object_weak_unref (G_OBJECT (a11y_col_header), eti_column_header_a11y_gone, a11y);
+}
+
+static void
+eti_column_header_a11y_gone (gpointer user_data,
+                            GObject *a11y_col_header)
+{
+       GalA11yETableItem *a11y = user_data;
+       GalA11yETableItemPrivate *priv;
+       GHashTableIter iter;
+       gpointer key, value;
+
+       g_return_if_fail (GAL_A11Y_IS_E_TABLE_ITEM (a11y));
+
+       priv = GET_PRIVATE (a11y);
+
+       g_hash_table_iter_init (&iter, priv->a11y_column_headers);
+       while (g_hash_table_iter_next (&iter, &key, &value)) {
+               ETableCol *col = key;
+               GalA11yETableColumnHeader *stored_a11y_col_header = value;
+
+               if (((GObject *) stored_a11y_col_header) == a11y_col_header) {
+                       g_object_weak_unref (G_OBJECT (col), eti_table_column_gone, a11y);
+                       g_hash_table_remove (priv->a11y_column_headers, col);
+                       break;
+               }
+       }
+}
+
 static void
 eti_dispose (GObject *object)
 {
        GalA11yETableItem *a11y = GAL_A11Y_E_TABLE_ITEM (object);
        GalA11yETableItemPrivate *priv = GET_PRIVATE (a11y);
+       GHashTableIter iter;
+       gpointer key, value;
 
        if (priv->columns) {
                free_columns (priv->columns);
@@ -289,10 +344,35 @@ eti_dispose (GObject *object)
                priv->item = NULL;
        }
 
+       g_clear_object (&priv->state_set);
+
+       g_hash_table_iter_init (&iter, priv->a11y_column_headers);
+       while (g_hash_table_iter_next (&iter, &key, &value)) {
+               ETableCol *col = key;
+               GalA11yETableColumnHeader *a11y_col_header = value;
+
+               g_object_weak_unref (G_OBJECT (col), eti_table_column_gone, a11y);
+               g_object_weak_unref (G_OBJECT (a11y_col_header), eti_column_header_a11y_gone, a11y);
+       }
+
+       g_hash_table_remove_all (priv->a11y_column_headers);
+
        if (parent_class->dispose)
                parent_class->dispose (object);
 }
 
+static void
+eti_finalize (GObject *object)
+{
+       GalA11yETableItem *a11y = GAL_A11Y_E_TABLE_ITEM (object);
+       GalA11yETableItemPrivate *priv = GET_PRIVATE (a11y);
+
+       g_hash_table_destroy (priv->a11y_column_headers);
+
+       if (parent_class->finalize)
+               parent_class->finalize (object);
+}
+
 /* Static functions */
 static gint
 eti_get_n_children (AtkObject *accessible)
@@ -318,12 +398,24 @@ eti_ref_child (AtkObject *accessible,
                return NULL;
 
        if (index < item->cols) {
+               GalA11yETableItemPrivate *priv = GET_PRIVATE (accessible);
                ETableCol *ecol;
                AtkObject *child;
 
                ecol = e_table_header_get_column (item->header, index);
-               child = gal_a11y_e_table_column_header_new (ecol, item, accessible);
-               return child;
+               child = g_hash_table_lookup (priv->a11y_column_headers, ecol);
+
+               if (!child) {
+                       child = gal_a11y_e_table_column_header_new (ecol, item, accessible);
+                       if (child) {
+                               g_hash_table_insert (priv->a11y_column_headers, ecol, child);
+
+                               g_object_weak_ref (G_OBJECT (ecol), eti_table_column_gone, accessible);
+                               g_object_weak_ref (G_OBJECT (child), eti_column_header_a11y_gone, accessible);
+                       }
+               }
+
+               return child ? g_object_ref (child) : NULL;
        }
        index -= item->cols;
 
@@ -966,6 +1058,7 @@ eti_header_structure_changed (ETableHeader *eth,
                g_free (state);
                g_free (reorder);
                g_free (prev_state);
+               free_columns (cols);
                return;
        }
 
@@ -1051,6 +1144,7 @@ eti_class_init (GalA11yETableItemClass *class)
        parent_class = g_type_class_ref (PARENT_TYPE);
 
        object_class->dispose = eti_dispose;
+       object_class->finalize = eti_finalize;
 
        atk_object_class->get_n_children = eti_get_n_children;
        atk_object_class->ref_child = eti_ref_child;
@@ -1069,6 +1163,7 @@ eti_init (GalA11yETableItem *a11y)
        priv->selection_row_changed_id = 0;
        priv->cursor_changed_id = 0;
        priv->selection = NULL;
+       priv->a11y_column_headers = g_hash_table_new (g_direct_hash, g_direct_equal);
 }
 
 /* atk selection */
@@ -1189,14 +1284,17 @@ gal_a11y_e_table_item_new (ETableItem *item)
 
        accessible = ATK_OBJECT (a11y);
 
-       GET_PRIVATE (a11y)->item = item;
        /* Initialize cell data. */
        GET_PRIVATE (a11y)->cols = item->cols;
        GET_PRIVATE (a11y)->rows = item->rows >= 0 ? item->rows : 0;
 
        GET_PRIVATE (a11y)->columns = e_table_header_get_columns (item->header);
-       if (GET_PRIVATE (a11y)->columns == NULL)
+       if (GET_PRIVATE (a11y)->columns == NULL) {
+               g_clear_object (&a11y);
                return NULL;
+       }
+
+       GET_PRIVATE (a11y)->item = item;
 
        g_signal_connect (
                item, "selection_model_removed",