path: root/widgets/table/gal-a11y-e-table-item.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Christopher James Lahey <clahey@ximian.com>
 *      Bolian Yin <bolian.yin@sun.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>

#include <atk/atk.h>

#include "a11y/gal-a11y-util.h"
#include "table/e-table-click-to-add.h"
#include "table/e-table-subset.h"
#include "table/e-table.h"
#include "table/e-tree.h"
#include "misc/e-canvas.h"
#include "misc/e-selection-model.h"

#include "gal-a11y-e-table-item.h"
#include "gal-a11y-e-table-item-factory.h"
#include "gal-a11y-e-table-click-to-add.h"
#include "gal-a11y-e-cell-registry.h"
#include "gal-a11y-e-cell.h"
#include "gal-a11y-e-table-column-header.h"

static GObjectClass *parent_class;
static AtkComponentIface *component_parent_iface;
static GType parent_type;
static gint priv_offset;
static GQuark       quark_accessible_object = 0;
#define GET_PRIVATE(object) \
    ((GalA11yETableItemPrivate *) (((gchar *) object) + priv_offset))
#define PARENT_TYPE (parent_type)

struct _GalA11yETableItemPrivate {
    gint cols;
    gint rows;
    gint selection_change_id;
    gint cursor_change_id;
    ETableCol ** columns;
    ESelectionModel *selection;
    AtkStateSet *state_set;
    GtkWidget *widget;
};

static gboolean gal_a11y_e_table_item_ref_selection (GalA11yETableItem *a11y,
                             ESelectionModel *selection);
static gboolean gal_a11y_e_table_item_unref_selection (GalA11yETableItem *a11y);

static AtkObject* eti_ref_at (AtkTable *table, gint row, gint column);

static void
item_finalized (gpointer user_data, GObject *gone_item)
{
    GalA11yETableItem *a11y;
    GalA11yETableItemPrivate *priv;

    /* XXX GalA11yETableItem may already be finalized.
     *     Just work around it for now. */
    if (!GAL_A11Y_IS_E_TABLE_ITEM (user_data))
        return;

    a11y = GAL_A11Y_E_TABLE_ITEM (user_data);
    priv = GET_PRIVATE (a11y);

    atk_state_set_add_state (priv->state_set, ATK_STATE_DEFUNCT);
    atk_object_notify_state_change (ATK_OBJECT (a11y), ATK_STATE_DEFUNCT, TRUE);

    if (priv->selection)
        gal_a11y_e_table_item_unref_selection (a11y);

}

static AtkStateSet *
eti_ref_state_set (AtkObject *accessible)
{
    GalA11yETableItemPrivate *priv = GET_PRIVATE (accessible);

    g_object_ref (priv->state_set);

    return priv->state_set;
}

inline static gint
view_to_model_row (ETableItem *eti, gint row)
{
    if (eti->uses_source_model) {
        ETableSubset *etss = E_TABLE_SUBSET (eti->table_model);
        if (row >= 0 && row < etss->n_map) {
            eti->row_guess = row;
            return etss->map_table[row];
        } else
            return -1;
    } else
        return row;
}

inline static gint
view_to_model_col (ETableItem *eti, gint col)
{
    ETableCol *ecol = e_table_header_get_column (eti->header, col);
    return ecol ? ecol->col_idx : -1;
}

inline static gint
model_to_view_row (ETableItem *eti, gint row)
{
    gint i;
    if (row == -1)
        return -1;
    if (eti->uses_source_model) {
        ETableSubset *etss = E_TABLE_SUBSET (eti->table_model);
        if (eti->row_guess >= 0 && eti->row_guess < etss->n_map) {
            if (etss->map_table[eti->row_guess] == row) {
                return eti->row_guess;
            }
        }
        for (i = 0; i < etss->n_map; i++) {
            if (etss->map_table[i] == row)
                return i;
        }
        return -1;
    } else
        return row;
}

inline static gint
model_to_view_col (ETableItem *eti, gint col)
{
    gint i;
    if (col == -1)
        return -1;
    for (i = 0; i < eti->cols; i++) {
        ETableCol *ecol = e_table_header_get_column (eti->header, i);
        if (ecol->col_idx == col)
            return i;
    }
    return -1;
}

inline static GObject *
eti_a11y_get_gobject (AtkObject *accessible)
{
    return atk_gobject_accessible_get_object (ATK_GOBJECT_ACCESSIBLE (accessible));
}

static void
eti_a11y_reset_focus_object (GalA11yETableItem *a11y,
                             ETableItem *item,
                             gboolean notify)
{
    ESelectionModel * esm;
    gint cursor_row, cursor_col, view_row, view_col;
    AtkObject *cell, *old_cell;

    esm = item->selection;
    g_return_if_fail (esm);

    cursor_row = e_selection_model_cursor_row (esm);
    cursor_col = e_selection_model_cursor_col (esm);

    view_row = model_to_view_row (item, cursor_row);
    view_col = model_to_view_col (item, cursor_col);

    if (view_row == -1)
        view_row = 0;
    if (view_col == -1)
        view_col = 0;

    old_cell = (AtkObject *)g_object_get_data (G_OBJECT (a11y), "gail-focus-object");
    if (old_cell && GAL_A11Y_IS_E_CELL (old_cell))
        gal_a11y_e_cell_remove_state (
            GAL_A11Y_E_CELL (old_cell), ATK_STATE_FOCUSED, FALSE);
    if (old_cell)
        g_object_unref (old_cell);

    cell = eti_ref_at (ATK_TABLE (a11y), view_row, view_col);

    if (cell != NULL) {
        g_object_set_data (G_OBJECT (a11y), "gail-focus-object", cell);
        gal_a11y_e_cell_add_state (
            GAL_A11Y_E_CELL (cell), ATK_STATE_FOCUSED, FALSE);
    } else
        g_object_set_data (G_OBJECT (a11y), "gail-focus-object", NULL);

    if (notify && cell)
        atk_focus_tracker_notify (cell);
}

static void
eti_dispose (GObject *object)
{
    GalA11yETableItem *a11y = GAL_A11Y_E_TABLE_ITEM (object);
    GalA11yETableItemPrivate *priv = GET_PRIVATE (a11y);

    if (priv->columns) {
        g_free (priv->columns);
        priv->columns = NULL;
    }

    if (parent_class->dispose)
        parent_class->dispose (object);
}

/* Static functions */
static gint
eti_get_n_children (AtkObject *accessible)
{
    g_return_val_if_fail (GAL_A11Y_IS_E_TABLE_ITEM (accessible), 0);
    if (!eti_a11y_get_gobject (accessible))
        return 0;

    return atk_table_get_n_columns (ATK_TABLE (accessible)) *
        (atk_table_get_n_rows (ATK_TABLE (accessible)) + 1);
}

static AtkObject*
eti_ref_child (AtkObject *accessible, gint index)
{
    ETableItem *item;
    gint col, row;

    g_return_val_if_fail (GAL_A11Y_IS_E_TABLE_ITEM (accessible), NULL);
    item = E_TABLE_ITEM (eti_a11y_get_gobject (accessible));
    if (!item)
        return NULL;

    if (index < item->cols) {
        ETableCol *ecol;
        AtkObject *child;

        ecol = e_table_header_get_column (item->header, index);
        child = gal_a11y_e_table_column_header_new (ecol, item);
        return child;
    }
    index -= item->cols;

    col = index % item->cols;
    row = index / item->cols;

    return eti_ref_at (ATK_TABLE (accessible), row, col);
}

static void
eti_get_extents (AtkComponent *component,
         gint *x,
         gint *y,
         gint *width,
         gint *height,
         AtkCoordType coord_type)
{
    ETableItem *item;
    AtkObject *parent;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (component)));
    if (!item)
        return;

    parent = ATK_OBJECT (component)->accessible_parent;
    if (parent && ATK_IS_COMPONENT (parent))
        atk_component_get_extents (ATK_COMPONENT (parent), x, y,
                    width, height,
                    coord_type);

    if (parent && GAL_A11Y_IS_E_TABLE_CLICK_TO_ADD (parent)) {
        ETableClickToAdd *etcta = E_TABLE_CLICK_TO_ADD (
            atk_gobject_accessible_get_object (
            ATK_GOBJECT_ACCESSIBLE (parent)));
        if (etcta) {
            *width = etcta->width;
            *height = etcta->height;
        }
    }
}

static AtkObject*
eti_ref_accessible_at_point (AtkComponent *component,
                 gint x,
                 gint y,
                 AtkCoordType coord_type)
{
    gint row = -1;
    gint col = -1;
    gint x_origin, y_origin;
    ETableItem *item;
    GtkWidget *tableOrTree;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (component)));
    if (!item)
        return NULL;

    atk_component_get_position (component,
                    &x_origin,
                    &y_origin,
                    coord_type);
    x -= x_origin;
    y -= y_origin;

    tableOrTree = gtk_widget_get_parent (GTK_WIDGET (item->parent.canvas));

    if (E_IS_TREE (tableOrTree))
        e_tree_get_cell_at (E_TREE (tableOrTree), x, y, &row, &col);
    else
        e_table_get_cell_at (E_TABLE (tableOrTree), x, y, &row, &col);

    if (row != -1 && col != -1) {
        return eti_ref_at (ATK_TABLE (component), row, col);
    } else {
        return NULL;
    }
}

static void
cell_destroyed (gpointer data)
{
    GalA11yECell * cell;

    g_return_if_fail (GAL_A11Y_IS_E_CELL (data));
    cell = GAL_A11Y_E_CELL (data);

    g_return_if_fail (cell->item && G_IS_OBJECT (cell->item));

    if (cell->item) {
        g_object_unref (cell->item);
        cell->item = NULL;
    }

}

/* atk table */
static AtkObject*
eti_ref_at (AtkTable *table, gint row, gint column)
{
    ETableItem *item;
    AtkObject* ret;
    GalA11yETableItemPrivate *priv = GET_PRIVATE (table);

    if (atk_state_set_contains_state (priv->state_set, ATK_STATE_DEFUNCT))
        return NULL;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return NULL;

    if (column >= 0 &&
        column < item->cols &&
        row >= 0 &&
        row < item->rows &&
        item->cell_views_realized) {
        ECellView *cell_view = item->cell_views[column];
        ETableCol *ecol = e_table_header_get_column (item->header, column);
        ret = gal_a11y_e_cell_registry_get_object (NULL,
                                item,
                                cell_view,
                                ATK_OBJECT (table),
                                ecol->col_idx,
                                column,
                                row);
        if (ATK_IS_OBJECT (ret)) {
            g_object_weak_ref (G_OBJECT (ret),
                       (GWeakNotify) cell_destroyed,
                       ret);
            /* if current cell is focused, add FOCUSED state */
            if (e_selection_model_cursor_row (item->selection) ==
                GAL_A11Y_E_CELL (ret)->row &&
                e_selection_model_cursor_col (item->selection) ==
                GAL_A11Y_E_CELL (ret)->model_col)
                gal_a11y_e_cell_add_state (
                    GAL_A11Y_E_CELL (ret),
                    ATK_STATE_FOCUSED, FALSE);
        } else
            ret = NULL;

        return ret;
    }

    return NULL;
}

static gint
eti_get_index_at (AtkTable *table, gint row, gint column)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    return column + (row + 1) * item->cols;
}

static gint
eti_get_column_at_index (AtkTable *table, gint index)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    return index % item->cols;
}

static gint
eti_get_row_at_index (AtkTable *table, gint index)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    return index / item->cols - 1;
}

static gint
eti_get_n_columns (AtkTable *table)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    return item->cols;
}

static gint
eti_get_n_rows (AtkTable *table)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    return item->rows;
}

static gint
eti_get_column_extent_at (AtkTable *table,
              gint row,
              gint column)
{
    ETableItem *item;
    gint width;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    e_table_item_get_cell_geometry (item,
                    &row,
                    &column,
                    NULL,
                    NULL,
                    &width,
                    NULL);

    return width;
}

static gint
eti_get_row_extent_at (AtkTable *table,
               gint row,
               gint column)
{
    ETableItem *item;
    gint height;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return -1;

    e_table_item_get_cell_geometry (item,
                    &row,
                    &column,
                    NULL,
                    NULL,
                    NULL,
                    &height);

    return height;
}

static AtkObject *
eti_get_caption (AtkTable *table)
{
    /* Unimplemented */
    return NULL;
}

static G_CONST_RETURN gchar *
eti_get_column_description (AtkTable *table,
                gint column)
{
    ETableItem *item;
    ETableCol *ecol;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return NULL;

    ecol = e_table_header_get_column (item->header, column);

    return ecol->text;
}

static AtkObject *
eti_get_column_header (AtkTable *table, gint column)
{
    ETableItem *item;
    ETableCol *ecol;
    AtkObject *atk_obj = NULL;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return NULL;

    ecol = e_table_header_get_column (item->header, column);
    if (ecol) {
        atk_obj = gal_a11y_e_table_column_header_new (ecol, item);
    }

    return atk_obj;
}

static G_CONST_RETURN gchar *
eti_get_row_description (AtkTable *table,
             gint row)
{
    /* Unimplemented */
    return NULL;
}

static AtkObject *
eti_get_row_header (AtkTable *table,
            gint row)
{
    /* Unimplemented */
    return NULL;
}

static AtkObject *
eti_get_summary (AtkTable *table)
{
    /* Unimplemented */
    return NULL;
}

static gboolean
table_is_row_selected (AtkTable *table, gint row)
{
    ETableItem *item;
    GalA11yETableItemPrivate *priv = GET_PRIVATE (table);

    if (row < 0)
        return FALSE;

    if (atk_state_set_contains_state (priv->state_set, ATK_STATE_DEFUNCT))
        return FALSE;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return FALSE;

    return e_selection_model_is_row_selected (
        item->selection, view_to_model_row (item, row));
}

static gboolean
table_is_selected (AtkTable *table, gint row, gint column)
{
    return table_is_row_selected (table, row);
}

static gint
table_get_selected_rows (AtkTable *table, gint **rows_selected)
{
    ETableItem *item;
    gint n_selected, row, index_selected;
    GalA11yETableItemPrivate *priv = GET_PRIVATE (table);

    if (atk_state_set_contains_state (priv->state_set, ATK_STATE_DEFUNCT))
        return 0;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return 0;

    n_selected = e_selection_model_selected_count (item->selection);
    if (rows_selected) {
        *rows_selected = (gint *) g_malloc (n_selected * sizeof (gint));

        index_selected = 0;
        for (row = 0; row < item->rows && index_selected < n_selected; ++row) {
            if (atk_table_is_row_selected (table, row)) {
                (*rows_selected)[index_selected] = row;
                ++index_selected;
            }
        }
    }
    return n_selected;
}

static gboolean
table_add_row_selection (AtkTable *table, gint row)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return FALSE;

    if (table_is_row_selected (table, row))
        return TRUE;
    e_selection_model_toggle_single_row (item->selection,
                         view_to_model_row (item, row));

    return TRUE;
}

static gboolean
table_remove_row_selection (AtkTable *table, gint row)
{
    ETableItem *item;
    GalA11yETableItemPrivate *priv = GET_PRIVATE (table);

    if (atk_state_set_contains_state (priv->state_set, ATK_STATE_DEFUNCT))
        return FALSE;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (table)));
    if (!item)
        return FALSE;

    if (!atk_table_is_row_selected (table, row))
        return TRUE;

    e_selection_model_toggle_single_row (
        item->selection, view_to_model_row (item, row));

    return TRUE;
}

static void
eti_atk_table_iface_init (AtkTableIface *iface)
{
    iface->ref_at = eti_ref_at;
    iface->get_index_at = eti_get_index_at;
    iface->get_column_at_index = eti_get_column_at_index;
    iface->get_row_at_index = eti_get_row_at_index;
    iface->get_n_columns = eti_get_n_columns;
    iface->get_n_rows = eti_get_n_rows;
    iface->get_column_extent_at = eti_get_column_extent_at;
    iface->get_row_extent_at = eti_get_row_extent_at;
    iface->get_caption = eti_get_caption;
    iface->get_column_description = eti_get_column_description;
    iface->get_column_header = eti_get_column_header;
    iface->get_row_description = eti_get_row_description;
    iface->get_row_header = eti_get_row_header;
    iface->get_summary = eti_get_summary;

    iface->is_row_selected = table_is_row_selected;
    iface->is_selected = table_is_selected;
    iface->get_selected_rows = table_get_selected_rows;
    iface->add_row_selection = table_add_row_selection;
    iface->remove_row_selection = table_remove_row_selection;
}

static void
eti_atk_component_iface_init (AtkComponentIface *iface)
{
    component_parent_iface         = g_type_interface_peek_parent (iface);

    iface->ref_accessible_at_point = eti_ref_accessible_at_point;
    iface->get_extents             = eti_get_extents;
}

static void
eti_rows_inserted (ETableModel * model, gint row, gint count,
           AtkObject * table_item)
{
    gint n_cols,n_rows,i,j;
    GalA11yETableItem * item_a11y;
    gint old_nrows;

    g_return_if_fail (table_item);
    item_a11y = GAL_A11Y_E_TABLE_ITEM (table_item);

    n_cols = atk_table_get_n_columns (ATK_TABLE (table_item));
    n_rows = atk_table_get_n_rows (ATK_TABLE (table_item));

    old_nrows = GET_PRIVATE (item_a11y)->rows;

    g_return_if_fail (n_cols > 0 && n_rows > 0);
    g_return_if_fail (old_nrows == n_rows - count);

    GET_PRIVATE (table_item)->rows = n_rows;

    g_signal_emit_by_name (table_item, "row-inserted", row,
                   count, NULL);

    for (i = row; i < (row + count); i++) {
        for (j = 0; j < n_cols; j++) {
            g_signal_emit_by_name (table_item,
                           "children_changed::add",
                           ( ((i + 1)*n_cols) + j), NULL, NULL);
        }
    }

    g_signal_emit_by_name (table_item, "visible-data-changed");
}

static void
eti_rows_deleted (ETableModel * model, gint row, gint count,
          AtkObject * table_item)
{
    gint i,j, n_rows, n_cols, old_nrows;
    ETableItem *item = E_TABLE_ITEM (
        atk_gobject_accessible_get_object (
        ATK_GOBJECT_ACCESSIBLE (table_item)));

    n_rows = atk_table_get_n_rows (ATK_TABLE (table_item));
    n_cols = atk_table_get_n_columns (ATK_TABLE (table_item));

    old_nrows = GET_PRIVATE (table_item)->rows;

    g_return_if_fail ( row+count <= old_nrows);
    g_return_if_fail (old_nrows == n_rows + count);
    GET_PRIVATE (table_item)->rows = n_rows;

    g_signal_emit_by_name (table_item, "row-deleted", row,
                   count, NULL);

    for (i = row; i < (row + count); i++) {
        for (j = 0; j < n_cols; j++) {
            g_signal_emit_by_name (table_item,
                           "children_changed::remove",
                           ( ((i + 1)*n_cols) + j), NULL, NULL);
        }
    }
    g_signal_emit_by_name (table_item, "visible-data-changed");
    eti_a11y_reset_focus_object ((GalA11yETableItem *) table_item, item, TRUE);
}

static void
eti_tree_model_node_changed_cb (ETreeModel *model, ETreePath node, ETableItem *eti)
{
    AtkObject *atk_obj;
    GalA11yETableItem *a11y;

    g_return_if_fail (E_IS_TABLE_ITEM (eti));

    atk_obj = atk_gobject_accessible_for_object (G_OBJECT (eti));
    a11y = GAL_A11Y_E_TABLE_ITEM (atk_obj);

    /* we can't figure out which rows are changed, so just send out a signal ... */
    if  (GET_PRIVATE (a11y)->rows > 0)
        g_signal_emit_by_name (a11y, "visible-data-changed");
}

enum {
        ETI_HEADER_UNCHANGED = 0,
        ETI_HEADER_REORDERED,
        ETI_HEADER_NEW_ADDED,
        ETI_HEADER_REMOVED
};

/*
 * 1. Check what actually happened: column reorder, remove or add
 * 2. Update cache
 * 3. Emit signals
 */
static void
eti_header_structure_changed (ETableHeader *eth, AtkObject *a11y)
{

    gboolean reorder_found=FALSE, added_found=FALSE, removed_found=FALSE;
    GalA11yETableItem * a11y_item;
    ETableCol ** cols, **prev_cols;
    GalA11yETableItemPrivate *priv;
    gint *state = NULL, *prev_state = NULL, *reorder = NULL;
    gint i,j,n_rows,n_cols, prev_n_cols;

    a11y_item = GAL_A11Y_E_TABLE_ITEM (a11y);
    priv = GET_PRIVATE (a11y_item);

    /* Assume rows do not changed. */
    n_rows = priv->rows;

    prev_n_cols = priv->cols;
    prev_cols = priv->columns;

    cols = e_table_header_get_columns (eth);
    n_cols = eth->col_count;

    g_return_if_fail (cols && prev_cols && n_cols > 0);

        /* Init to ETI_HEADER_UNCHANGED. */
    state = g_malloc0 (sizeof (gint) * n_cols);
    prev_state = g_malloc0 (sizeof (gint) * prev_n_cols);
    reorder = g_malloc0 (sizeof (gint) * n_cols);

        /* Compare with previously saved column headers. */
    for (i = 0; i < n_cols && cols[i]; i++) {
        for (j = 0; j < prev_n_cols && prev_cols[j]; j++) {
            if (prev_cols[j] == cols[i] && i != j) {

                reorder_found = TRUE;
                state[i] = ETI_HEADER_REORDERED;
                reorder[i] = j;

                break;
            } else if (prev_cols[j] == cols[i]) {
                                /* OK, this column is not changed. */
                break;
            }
        }

                /* cols[i] is new added column. */
        if (j == prev_n_cols) {
            added_found = TRUE;
            state[i] = ETI_HEADER_NEW_ADDED;
        }
    }

        /* Now try to find if there are removed columns. */
    for (i = 0; i < prev_n_cols && prev_cols[i]; i++) {
        for (j = 0; j < n_cols && cols[j]; j++)
            if (prev_cols[j] == cols[i])
                break;

                /* Removed columns found. */
        if (j == n_cols) {
            removed_found = TRUE;
            prev_state[j] = ETI_HEADER_REMOVED;
        }
    }

    /* If nothing interesting just return. */
    if (!reorder_found && !added_found && !removed_found)
        return;

    /* Emit signals */
    if (reorder_found)
        g_signal_emit_by_name (G_OBJECT(a11y_item), "column_reordered");

    if (removed_found) {
        for (i = 0; i < prev_n_cols; i ++ ) {
            if (prev_state[i] == ETI_HEADER_REMOVED) {
                g_signal_emit_by_name (
                    G_OBJECT (a11y_item),
                    "column-deleted", i, 1);
                for (j = 0; j < n_rows; j++)
                    g_signal_emit_by_name (
                        G_OBJECT (a11y_item),
                        "children_changed::remove",
                        ((j+1)*prev_n_cols+i),
                        NULL, NULL);
            }
        }
    }

    if (added_found) {
        for (i = 0; i < n_cols; i++) {
            if (state[i] == ETI_HEADER_NEW_ADDED) {
                g_signal_emit_by_name (
                    G_OBJECT (a11y_item),
                    "column-inserted", i, 1);
                for (j = 0; j < n_rows; j++)
                    g_signal_emit_by_name (
                        G_OBJECT (a11y_item),
                        "children_changed::add",
                        ((j+1)*n_cols+i),
                        NULL, NULL);
            }
        }
    }

    priv->cols = n_cols;

    g_free (state);
    g_free (reorder);
    g_free (prev_state);

    g_free (priv->columns);
    priv->columns = cols;
}

static void
eti_real_initialize (AtkObject *obj,
             gpointer data)
{
    ETableItem * eti;
    ETableModel * model;

    ATK_OBJECT_CLASS (parent_class)->initialize (obj, data);
    eti = E_TABLE_ITEM (data);

    model = eti->table_model;

    g_signal_connect (model, "model-rows-inserted",
              G_CALLBACK (eti_rows_inserted),
              obj);
    g_signal_connect (model, "model-rows-deleted",
              G_CALLBACK (eti_rows_deleted),
              obj);
    g_signal_connect (G_OBJECT (eti->header), "structure_change",
              G_CALLBACK (eti_header_structure_changed), obj);

}

static void
eti_class_init (GalA11yETableItemClass *class)
{
    AtkObjectClass *atk_object_class = ATK_OBJECT_CLASS (class);
    GObjectClass *object_class = G_OBJECT_CLASS (class);

    quark_accessible_object =
        g_quark_from_static_string ("gtk-accessible-object");

    parent_class = g_type_class_ref (PARENT_TYPE);

    object_class->dispose = eti_dispose;

    atk_object_class->get_n_children = eti_get_n_children;
    atk_object_class->ref_child = eti_ref_child;
    atk_object_class->initialize = eti_real_initialize;
    atk_object_class->ref_state_set = eti_ref_state_set;
}

static void
eti_init (GalA11yETableItem *a11y)
{
    GalA11yETableItemPrivate *priv;

    priv = GET_PRIVATE (a11y);

    priv->selection_change_id = 0;
    priv->cursor_change_id = 0;
    priv->selection = NULL;
}

/* atk selection */

static void atk_selection_interface_init    (AtkSelectionIface *iface);
static gboolean selection_add_selection     (AtkSelection *selection,
                         gint i);
static gboolean selection_clear_selection   (AtkSelection *selection);
static AtkObject *
        selection_ref_selection     (AtkSelection *selection,
                         gint i);
static gint selection_get_selection_count   (AtkSelection *selection);
static gboolean selection_is_child_selected (AtkSelection *selection,
                         gint i);

/* callbacks */
static void eti_a11y_selection_model_removed_cb (ETableItem *eti,
                         ESelectionModel *selection,
                         gpointer data);
static void eti_a11y_selection_model_added_cb (ETableItem *eti,
                           ESelectionModel *selection,
                           gpointer data);
static void eti_a11y_selection_changed_cb (ESelectionModel *selection,
                       GalA11yETableItem *a11y);
static void eti_a11y_cursor_changed_cb (ESelectionModel *selection,
                    gint row, gint col,
                    GalA11yETableItem *a11y);

/**
 * gal_a11y_e_table_item_get_type:
 * @void:
 *
 * Registers the &GalA11yETableItem class if necessary, and returns the type ID
 * associated to it.
 *
 * Return value: The type ID of the &GalA11yETableItem class.
 **/
GType
gal_a11y_e_table_item_get_type (void)
{
    static GType type = 0;

    if (!type) {
        AtkObjectFactory *factory;

        GTypeInfo info = {
            sizeof (GalA11yETableItemClass),
            (GBaseInitFunc) NULL,
            (GBaseFinalizeFunc) NULL,
            (GClassInitFunc) eti_class_init,
            (GClassFinalizeFunc) NULL,
            NULL, /* class_data */
            sizeof (GalA11yETableItem),
            0,
            (GInstanceInitFunc) eti_init,
            NULL /* value_table_item */
        };

        static const GInterfaceInfo atk_component_info = {
            (GInterfaceInitFunc) eti_atk_component_iface_init,
            (GInterfaceFinalizeFunc) NULL,
            NULL
        };
        static const GInterfaceInfo atk_table_info = {
            (GInterfaceInitFunc) eti_atk_table_iface_init,
            (GInterfaceFinalizeFunc) NULL,
            NULL
        };

        static const GInterfaceInfo atk_selection_info = {
            (GInterfaceInitFunc) atk_selection_interface_init,
            (GInterfaceFinalizeFunc) NULL,
            NULL
        };

        factory = atk_registry_get_factory (
            atk_get_default_registry (), GNOME_TYPE_CANVAS_ITEM);
        parent_type = atk_object_factory_get_accessible_type (factory);

        type = gal_a11y_type_register_static_with_private (
            PARENT_TYPE, "GalA11yETableItem", &info, 0,
            sizeof (GalA11yETableItemPrivate), &priv_offset);

        g_type_add_interface_static (type, ATK_TYPE_COMPONENT, &atk_component_info);
        g_type_add_interface_static (type, ATK_TYPE_TABLE, &atk_table_info);
        g_type_add_interface_static (type, ATK_TYPE_SELECTION, &atk_selection_info);
    }

    return type;
}

AtkObject *
gal_a11y_e_table_item_new (ETableItem *item)
{
    GalA11yETableItem *a11y;
    AtkObject *accessible;
    ESelectionModel * esm;
    AtkObject *parent;
    const gchar *name;

    g_return_val_if_fail (item && item->cols >= 0 && item->rows >= 0, NULL);
    a11y = g_object_new (gal_a11y_e_table_item_get_type (), NULL);

    atk_object_initialize (ATK_OBJECT (a11y), item);

    GET_PRIVATE (a11y)->state_set = atk_state_set_new ();

    atk_state_set_add_state (GET_PRIVATE (a11y)->state_set, ATK_STATE_TRANSIENT);
    atk_state_set_add_state (GET_PRIVATE (a11y)->state_set, ATK_STATE_ENABLED);
    atk_state_set_add_state (GET_PRIVATE (a11y)->state_set, ATK_STATE_SENSITIVE);
    atk_state_set_add_state (GET_PRIVATE (a11y)->state_set, ATK_STATE_SHOWING);
    atk_state_set_add_state (GET_PRIVATE (a11y)->state_set, ATK_STATE_VISIBLE);

    accessible  = ATK_OBJECT (a11y);

    /* Initialize cell data. */
    GET_PRIVATE (a11y)->cols = item->cols;
    GET_PRIVATE (a11y)->rows = item->rows;

    GET_PRIVATE (a11y)->columns = e_table_header_get_columns (item->header);
    if ( GET_PRIVATE (a11y)->columns == NULL)
        return NULL;

    if (item) {
        g_signal_connect (G_OBJECT(item), "selection_model_removed",
                  G_CALLBACK (eti_a11y_selection_model_removed_cb), NULL);
        g_signal_connect (G_OBJECT(item), "selection_model_added",
                  G_CALLBACK (eti_a11y_selection_model_added_cb), NULL);
        if (item->selection)
            gal_a11y_e_table_item_ref_selection (a11y,
                                 item->selection);

        /* find the TableItem's parent: table or tree */
        GET_PRIVATE (a11y)->widget = gtk_widget_get_parent (
            GTK_WIDGET (item->parent.canvas));
        parent = gtk_widget_get_accessible (GET_PRIVATE (a11y)->widget);
        name = atk_object_get_name (parent);
        if (name)
            atk_object_set_name (accessible, name);
        atk_object_set_parent (accessible, parent);

        if (E_IS_TREE (GET_PRIVATE (a11y)->widget)) {
            ETreeModel *model;
            model = e_tree_get_model (E_TREE (GET_PRIVATE (a11y)->widget));
            g_signal_connect (G_OBJECT(model), "node_changed",
                    G_CALLBACK (eti_tree_model_node_changed_cb), item);
            accessible->role = ATK_ROLE_TREE_TABLE;
        } else if (E_IS_TABLE (GET_PRIVATE (a11y)->widget)) {
            accessible->role = ATK_ROLE_TABLE;
        }
    }

    if (item)
        g_object_weak_ref (G_OBJECT (item), item_finalized, a11y);

    esm = item->selection;

    if (esm != NULL) {
        eti_a11y_reset_focus_object (a11y, item, FALSE);
    }

    return ATK_OBJECT (a11y);
}

static gboolean
gal_a11y_e_table_item_ref_selection (GalA11yETableItem *a11y,
                     ESelectionModel *selection)
{
    GalA11yETableItemPrivate *priv;

    g_return_val_if_fail (a11y && selection, FALSE);

    priv = GET_PRIVATE (a11y);
    priv->selection_change_id = g_signal_connect (
        G_OBJECT(selection), "selection_changed",
        G_CALLBACK (eti_a11y_selection_changed_cb), a11y);
    priv->cursor_change_id = g_signal_connect (
            G_OBJECT(selection), "cursor_changed",
        G_CALLBACK (eti_a11y_cursor_changed_cb), a11y);

    priv->selection = selection;
    g_object_ref (selection);

    return TRUE;
}

static gboolean
gal_a11y_e_table_item_unref_selection (GalA11yETableItem *a11y)
{
    GalA11yETableItemPrivate *priv;

    g_return_val_if_fail (a11y, FALSE);

    priv = GET_PRIVATE (a11y);

    g_return_val_if_fail (priv->selection_change_id != 0, FALSE);
    g_return_val_if_fail (priv->cursor_change_id != 0, FALSE);

    g_signal_handler_disconnect (priv->selection,
                     priv->selection_change_id);
    g_signal_handler_disconnect (priv->selection,
                     priv->cursor_change_id);
    priv->cursor_change_id = 0;
    priv->selection_change_id = 0;

    g_object_unref (priv->selection);
    priv->selection = NULL;

    return TRUE;
}

/* callbacks */

static void
eti_a11y_selection_model_removed_cb (ETableItem *eti, ESelectionModel *selection,
                     gpointer data)
{
    AtkObject *atk_obj;
    GalA11yETableItem *a11y;

    g_return_if_fail (E_IS_TABLE_ITEM (eti));
    g_return_if_fail (E_IS_SELECTION_MODEL (selection));

    atk_obj = atk_gobject_accessible_for_object (G_OBJECT (eti));
    a11y = GAL_A11Y_E_TABLE_ITEM (atk_obj);

    if (selection == GET_PRIVATE (a11y)->selection)
        gal_a11y_e_table_item_unref_selection (a11y);
}

static void
eti_a11y_selection_model_added_cb (ETableItem *eti, ESelectionModel *selection,
                   gpointer data)
{
    AtkObject *atk_obj;
    GalA11yETableItem *a11y;

    g_return_if_fail (E_IS_TABLE_ITEM (eti));
    g_return_if_fail (E_IS_SELECTION_MODEL (selection));

    atk_obj = atk_gobject_accessible_for_object (G_OBJECT (eti));
    a11y = GAL_A11Y_E_TABLE_ITEM (atk_obj);

    if (GET_PRIVATE (a11y)->selection)
        gal_a11y_e_table_item_unref_selection (a11y);
    gal_a11y_e_table_item_ref_selection (a11y, selection);
}

static void
eti_a11y_selection_changed_cb (ESelectionModel *selection, GalA11yETableItem *a11y)
{
    GalA11yETableItemPrivate *priv = GET_PRIVATE (a11y);

    if (atk_state_set_contains_state (priv->state_set, ATK_STATE_DEFUNCT))
        return;

    g_return_if_fail (GAL_A11Y_IS_E_TABLE_ITEM (a11y));

    g_signal_emit_by_name (a11y, "selection_changed");
}

static void
eti_a11y_cursor_changed_cb (ESelectionModel *selection,
                gint row, gint col,  GalA11yETableItem *a11y)
{
    ETableItem *item;
    GalA11yETableItemPrivate *priv = GET_PRIVATE (a11y);

    g_return_if_fail (GAL_A11Y_IS_E_TABLE_ITEM (a11y));

    if (atk_state_set_contains_state (priv->state_set, ATK_STATE_DEFUNCT))
        return;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (a11y)));

    g_return_if_fail (item);

    if (row == -1 && col == -1)
        return;
    eti_a11y_reset_focus_object (a11y, item, TRUE);
}

/* atk selection */

static void atk_selection_interface_init (AtkSelectionIface *iface)
{
    g_return_if_fail (iface != NULL);
    iface->add_selection = selection_add_selection;
    iface->clear_selection = selection_clear_selection;
    iface->ref_selection = selection_ref_selection;
    iface->get_selection_count = selection_get_selection_count;
    iface->is_child_selected = selection_is_child_selected;
}

static gboolean
selection_add_selection (AtkSelection *selection, gint index)
{
    AtkTable *table;
    gint row, col, cursor_row, cursor_col, model_row, model_col;
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (selection)));
    if (!item)
        return FALSE;

    table = ATK_TABLE (selection);

    row = atk_table_get_row_at_index (table, index);
    col = atk_table_get_column_at_index (table, index);

    model_row = view_to_model_row (item, row);
    model_col = view_to_model_col (item, col);

    cursor_row = e_selection_model_cursor_row (item->selection);
    cursor_col = e_selection_model_cursor_col (item->selection);

    /* check whether is selected already */
    if (model_row == cursor_row && model_col == cursor_col)
        return TRUE;

    if (model_row != cursor_row) {
        /* we need to make the item get focus */
        e_canvas_item_grab_focus (GNOME_CANVAS_ITEM (item), TRUE);

        /* FIXME, currently we only support single row selection */
        atk_selection_clear_selection (selection);
        atk_table_add_row_selection (table, row);
    }

    e_selection_model_change_cursor (item->selection,
                     model_row,
                     model_col);
    e_selection_model_cursor_changed (item->selection,
                      model_row,
                      model_col);
    e_selection_model_cursor_activated (item->selection,
                        model_row,
                        model_col);
    return TRUE;
}

static gboolean
selection_clear_selection (AtkSelection *selection)
{
    ETableItem *item;

    item = E_TABLE_ITEM (eti_a11y_get_gobject (ATK_OBJECT (selection)));
    if (!item)
        return FALSE;

    e_selection_model_clear (item->selection);
    return TRUE;
}

static AtkObject *
selection_ref_selection (AtkSelection *selection, gint index)
{
    AtkTable *table;
    gint row, col;

    table = ATK_TABLE (selection);
    row = atk_table_get_row_at_index (table, index);
    col = atk_table_get_column_at_index (table, index);
    if (!atk_table_is_row_selected (table, row))
        return NULL;

    return eti_ref_at (table, row, col);
}

static gint
selection_get_selection_count (AtkSelection *selection)
{
    AtkTable *table;
    gint n_selected;

    table = ATK_TABLE (selection);
    n_selected = atk_table_get_selected_rows (table, NULL);
    if (n_selected > 0)
        n_selected *= atk_table_get_n_columns (table);
    return n_selected;
}

static gboolean
selection_is_child_selected (AtkSelection *selection, gint i)
{
    gint row;

    row = atk_table_get_row_at_index (ATK_TABLE (selection), i);
    return atk_table_is_row_selected (ATK_TABLE (selection), row);
}

void
gal_a11y_e_table_item_init (void)
{
    if (atk_get_root ())
        atk_registry_set_factory_type (atk_get_default_registry (),
                    E_TYPE_TABLE_ITEM,
                    gal_a11y_e_table_item_factory_get_type ());
}