path: root/widgets/e-table/e-table.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * E-table.c: A graphical view of a Table.
 *
 * Author:
 *   Miguel de Icaza (miguel@gnu.org)
 *
 * Copyright 1999, Helix Code, Inc
 */
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#endif
#include <stdio.h>
#include <libgnomeui/gnome-canvas.h>
#include <gtk/gtksignal.h>
#include <gnome-xml/parser.h>
#include "e-util/e-util.h"
#include "e-util/e-xml-utils.h"
#include "e-table.h"
#include "e-table-header-item.h"
#include "e-table-subset.h"
#include "e-table-item.h"
#include "e-table-group.h"

#define COLUMN_HEADER_HEIGHT 16
#define TITLE_HEIGHT         16
#define GROUP_INDENT         10

#define PARENT_TYPE gtk_table_get_type ()

static GtkObjectClass *e_table_parent_class;

enum {
    ROW_SELECTION,
    LAST_SIGNAL
};

static gint et_signals [LAST_SIGNAL] = { 0, };

static void e_table_fill_table (ETable *e_table, ETableModel *model);
static gboolean changed_idle (gpointer data);

static void
et_destroy (GtkObject *object)
{
    ETable *et = E_TABLE (object);
    

    gtk_signal_disconnect (GTK_OBJECT (et->model),
                   et->table_model_change_id);
    gtk_signal_disconnect (GTK_OBJECT (et->model),
                   et->table_row_change_id);
    gtk_signal_disconnect (GTK_OBJECT (et->model),
                   et->table_cell_change_id);
    if (et->sort_info_change_id)
        gtk_signal_disconnect (GTK_OBJECT (et->sort_info),
                       et->sort_info_change_id);

    gtk_object_unref (GTK_OBJECT (et->model));
    gtk_object_unref (GTK_OBJECT (et->full_header));
    gtk_object_unref (GTK_OBJECT (et->header));
    gtk_object_unref (GTK_OBJECT (et->sort_info));
    gtk_widget_destroy (GTK_WIDGET (et->header_canvas));
    gtk_widget_destroy (GTK_WIDGET (et->table_canvas));

    if (et->rebuild_idle_id) {
        g_source_remove(et->rebuild_idle_id);
        et->rebuild_idle_id = 0;
    }
    
    xmlFreeDoc (et->specification);

    (*e_table_parent_class->destroy)(object);
}

static void
e_table_init (GtkObject *object)
{
    ETable *e_table = E_TABLE (object);
    
    e_table->sort_info = NULL;
    e_table->sort_info_change_id = 0;

    e_table->draw_grid = 1;
    e_table->draw_focus = 1;
    e_table->spreadsheet = 1;
    
    e_table->need_rebuild = 0;
    e_table->need_row_changes = 0;
    e_table->row_changes_list = NULL;
    e_table->rebuild_idle_id = 0;
}

static ETableHeader *
e_table_make_header (ETable *e_table, ETableHeader *full_header, xmlNode *xmlColumns)
{
    ETableHeader *nh;
    xmlNode *column;
    const int max_cols = e_table_header_count (full_header);
    
    nh = e_table_header_new ();
    for (column = xmlColumns->childs; column; column = column->next) {
        int col = atoi (column->childs->content);

        if (col >= max_cols)
            continue;

        e_table_header_add_column (nh, e_table_header_get_column (full_header, col), -1);
    }

    e_table_header_set_frozen_columns( nh, e_xml_get_integer_prop_by_name(xmlColumns, "frozen_columns") );
    
    return nh;
}

static void
header_canvas_size_alocate (GtkWidget *widget, GtkAllocation *alloc, ETable *e_table)
{
    gnome_canvas_set_scroll_region (
        GNOME_CANVAS (e_table->header_canvas),
        0, 0, alloc->width, COLUMN_HEADER_HEIGHT);
}

static void
sort_info_changed (ETableSortInfo *info, ETable *et)
{
    et->need_rebuild = TRUE;
    if ( !et->rebuild_idle_id ) {
        et->rebuild_idle_id = g_idle_add(changed_idle, et);
    }
}

static void
e_table_setup_header (ETable *e_table)
{
    xmlNode *root;
    xmlNode *grouping;
    e_table->header_canvas = GNOME_CANVAS (gnome_canvas_new ());
    
    gtk_widget_show (GTK_WIDGET (e_table->header_canvas));

    root = xmlDocGetRootElement(e_table->specification);
    grouping = e_xml_get_child_by_name(root, "grouping");

    e_table->sort_info = e_table_sort_info_new();
    
    gtk_object_ref(GTK_OBJECT(e_table->sort_info));
    gtk_object_sink(GTK_OBJECT(e_table->sort_info));

    gtk_object_set(GTK_OBJECT(e_table->sort_info),
               "grouping", grouping,
               NULL);

    e_table->sort_info_change_id = 
        gtk_signal_connect (GTK_OBJECT(e_table->sort_info), "sort_info_changed", 
                    GTK_SIGNAL_FUNC (sort_info_changed), e_table);

    e_table->header_item = gnome_canvas_item_new (
        gnome_canvas_root (e_table->header_canvas),
        e_table_header_item_get_type (),
        "ETableHeader", e_table->header,
        "x", 0,
        "y", 0,
        "sort_info", e_table->sort_info,
        NULL);

    gtk_signal_connect (
        GTK_OBJECT (e_table->header_canvas), "size_allocate",
        GTK_SIGNAL_FUNC (header_canvas_size_alocate), e_table);
                 
    gtk_widget_set_usize (GTK_WIDGET (e_table->header_canvas), -1, COLUMN_HEADER_HEIGHT);
    
    gtk_table_attach (
        GTK_TABLE (e_table), GTK_WIDGET (e_table->header_canvas),
        0, 1, 0, 1, GTK_FILL | GTK_EXPAND, 0, 0, 0);
        
}

#if 0
typedef struct {
    void *value;
    GArray *array;
} group_key_t;

static GArray *
e_table_create_groups (ETableModel *etm, int key_col, GCompareFunc comp)
{
    GArray *groups;
    const int rows = e_table_model_row_count (etm);
    int row, i;
    
    groups = g_array_new (FALSE, FALSE, sizeof (group_key_t));

    for (row = 0; row < rows; row++){
        void *val = e_table_model_value_at (etm, key_col, row);
        const int n_groups = groups->len;

        /*
         * Should replace this with a bsearch later
         */
        for (i = 0; i < n_groups; i++){
            group_key_t *g = &g_array_index (groups, group_key_t, i);
            
            if ((*comp) (g->value, val)){
                g_array_append_val (g->array, row);
                break;
            }
        }
        if (i != n_groups)
            continue;

        /*
         * We need to create a new group
         */
        {
            group_key_t gk;

            gk.value = val;
            gk.array = g_array_new (FALSE, FALSE, sizeof (int));

            g_array_append_val (gk.array, row);
            g_array_append_val (groups, gk);
        }
    }

    return groups;
}

static void
e_table_destroy_groups (GArray *groups)
{
    const int n = groups->len;
    int i;
    
    for (i = 0; i < n; i++){
        group_key_t *g = &g_array_index (groups, group_key_t, i);

        g_array_free (g->array, TRUE);
    }
    g_array_free (groups, TRUE);
}

static ETableModel **
e_table_make_subtables (ETableModel *model, GArray *groups)
{
    const int n_groups = groups->len;
    ETableModel **tables;
    int i;

    tables = g_new (ETableModel *, n_groups+1);

    for (i = 0; i < n_groups; i++){
        group_key_t *g = &g_array_index (groups, group_key_t, i);
        const int sub_size = g->array->len;
        ETableSubset *ss;
        int j;

        tables [i] = e_table_subset_new (model, sub_size);
        ss = E_TABLE_SUBSET (tables [i]);
        
        for (j = 0; j < sub_size; j++)
            ss->map_table [j] = g_array_index (g->array, int, j);
    }
    tables [i] = NULL;
        
    return (ETableModel **) tables;
}

typedef struct _Node Node;

struct _Node {
    Node            *parent;
    GnomeCanvasItem *item;
    ETableModel     *table_model;
    GSList          *children;

    guint is_leaf:1;
};

static Node *
leaf_new (GnomeCanvasItem *table_item, ETableModel *table_model, Node *parent)
{
    Node *node = g_new (Node, 1);

    g_assert (table_item != NULL);
    g_assert (table_model != NULL);
    g_assert (parent != NULL);
    
    node->item = table_item;
    node->parent = parent;
    node->table_model = table_model;
    node->is_leaf = 1;

    g_assert (!parent->is_leaf);
    
    parent->children = g_slist_append (parent->children, node);

    e_table_group_add (E_TABLE_GROUP (parent->item), table_item);

    return node;
}

static Node *
node_new (GnomeCanvasItem *group_item, ETableModel *table_model, Node *parent)
{
    Node *node = g_new (Node, 1);

    g_assert (table_model != NULL);

    node->children = NULL;
    node->item = group_item;
    node->parent = parent;
    node->table_model = table_model;
    node->is_leaf = 0;

    if (parent){
        parent->children = g_slist_append (parent->children, node);

        e_table_group_add (E_TABLE_GROUP (parent->item), group_item);
    }
    
    return node;
}

static Node *
e_table_create_leaf (ETable *e_table, ETableModel *etm, Node *parent)
{
    GnomeCanvasItem *table_item;
    Node *leaf;
    
    table_item = gnome_canvas_item_new (
        GNOME_CANVAS_GROUP (parent->item),
        e_table_item_get_type (),
        "ETableHeader", e_table->header,
        "ETableModel",  etm,
        "drawgrid", e_table->draw_grid,
        "drawfocus", e_table->draw_focus,
        "spreadsheet", e_table->spreadsheet,
        NULL);

    leaf = leaf_new (table_item, etm, parent);
    
    return leaf;
}

static int
leaf_height (Node *leaf)
{
    const GnomeCanvasItem *item = leaf->item;
    
    return item->y2 - item->y1;
}

static int
leaf_event (GnomeCanvasItem *item, GdkEvent *event)
{
    static int last_x = -1;
    static int last_y = -1;
    
    if (event->type == GDK_BUTTON_PRESS){
        last_x = event->button.x;
        last_y = event->button.y;
    } else if (event->type == GDK_BUTTON_RELEASE){
        last_x = -1;
        last_y = -1;
    } else if (event->type == GDK_MOTION_NOTIFY){
        if (last_x == -1)
            return FALSE;
        
        gnome_canvas_item_move (item, event->motion.x - last_x, event->motion.y - last_y);
        last_x = event->motion.x;
        last_y = event->motion.y;
    } else
        return FALSE;
    return TRUE;
}

static Node *
e_table_create_nodes (ETable *e_table, ETableModel *model, ETableHeader *header,
              GnomeCanvasGroup *root, Node *parent, int *groups_list)
{
    GArray *groups;
    ETableModel **tables;
    ETableCol *ecol;
    int key_col, i;
    GnomeCanvasItem *group_item;
    Node *group;

    key_col = *groups_list;
    g_assert (key_col != -1);
    
    /*
     * Create groups
     */
    ecol = e_table_header_get_column (header, key_col);

    g_assert (ecol != NULL);
    
    groups = e_table_create_groups (model, key_col, ecol->compare);
    tables = e_table_make_subtables (e_table->model, groups);
    e_table_destroy_groups (groups);
    group_item = gnome_canvas_item_new (root,
                        e_table_group_get_type(),
                        "columns", ecol, TRUE, parent == NULL);
    group = node_new (group_item, model, parent);
    
    for (i = 0; tables [i] != NULL; i++){
        /*
         * Leafs
         */
        if (groups_list [1] == -1){
            GnomeCanvasItem *item_leaf_header;
            Node *leaf_header;
            
            /* FIXME *//*
            item_leaf_header = e_table_group_new (
            GNOME_CANVAS_GROUP (group_item), ecol, TRUE, FALSE);*/
            leaf_header = node_new (item_leaf_header, tables [i], group);

            e_table_create_leaf (e_table, tables [i], leaf_header);
        } else {
            e_table_create_nodes (
                e_table, tables [i], header, GNOME_CANVAS_GROUP (group_item),
                group, &groups_list [1]);
        }
    }

    return group;
}

static int *
group_spec_to_desc (const char *group_spec)
{
    int a_size = 10;
    int *elements;
    char *p, *copy, *follow;
    int n_elements = 0;

    if (group_spec == NULL)
        return NULL;

    elements = g_new (int, a_size); 
    copy = alloca (strlen (group_spec) + 1);
    strcpy (copy, group_spec);

    while ((p = strtok_r (copy, ",", &follow)) != NULL){
        elements [n_elements] = atoi (p);
        ++n_elements;
        if (n_elements+1 == a_size){
            int *new_e;
            
            n_elements += 10;
            new_e = g_renew (int, elements, n_elements);
            if (new_e == NULL){
                g_free (elements);
                return NULL;
            }
            elements = new_e;
        }
        copy = NULL;
    }

    /* Tag end */
    elements [n_elements] = -1;
    
    return elements;
}

/*
 * The ETableCanvas object is just used to enable us to
 * hook up to the realize/unrealize phases of the canvas
 * initialization (as laying out the subtables requires us to
 * know the actual size of the subtables we are inserting
 */
 
#define E_TABLE_CANVAS_PARENT_TYPE gnome_canvas_get_type ()

typedef struct {
    GnomeCanvas base;

    ETable *e_table;
} ETableCanvas;

typedef struct {
    GnomeCanvasClass base_class;
} ETableCanvasClass;

static GnomeCanvasClass *e_table_canvas_parent_class;

static void
e_table_canvas_realize (GtkWidget *widget)
{
#if 0
    GnomeCanvasItem *group_item;
    
    group_item = gnome_canvas_item_new (root,
                        e_table_group_get_type(),
                        "header", E_TABLE, TRUE, parent == NULL);
    

    ETableCanvas *e_table_canvas = (ETableCanvas *) widget;
    ETable *e_table = e_table_canvas->e_table;
    int *groups;
    Node *leaf;
    
    GTK_WIDGET_CLASS (e_table_canvas_parent_class)->realize (widget);
    
    groups = group_spec_to_desc (e_table->group_spec);

    

    leaf = e_table_create_nodes (
        e_table, e_table->model,
        e_table->header, GNOME_CANVAS_GROUP (e_table->root), 0, groups);

    
    if (groups)
        g_free (groups);
#endif
}

static void
e_table_canvas_unrealize (GtkWidget *widget)
{
    ETableCanvas *e_table_canvas = (ETableCanvas *) widget;
    ETable *e_table = e_table_canvas->e_table;
    
    gtk_object_destroy (GTK_OBJECT (e_table->root));

    GTK_WIDGET_CLASS (e_table_canvas_parent_class)->unrealize (widget);
}

static void
e_table_canvas_class_init (GtkObjectClass *object_class)
{
    GtkWidgetClass *widget_class = (GtkWidgetClass *) object_class;

    widget_class->realize = e_table_canvas_realize;
    widget_class->unrealize = e_table_canvas_unrealize;

    e_table_canvas_parent_class = gtk_type_class (E_TABLE_CANVAS_PARENT_TYPE);
}

static void
e_table_canvas_init (GtkObject *canvas)
{
    ETableCanvas *e_table_canvas = (ETableCanvas *) (canvas);
    ETable *e_table = e_table_canvas->e_table;
    
    GTK_WIDGET_SET_FLAGS (canvas, GTK_CAN_FOCUS);

}

GtkType e_table_canvas_get_type (void);

E_MAKE_TYPE (e_table_canvas, "ETableCanvas", ETableCanvas, e_table_canvas_class_init,
         e_table_canvas_init, E_TABLE_CANVAS_PARENT_TYPE);

static GnomeCanvas *
e_table_canvas_new (ETable *e_table)
{
    ETableCanvas *e_table_canvas;

    e_table_canvas = gtk_type_new (e_table_canvas_get_type ());
    e_table_canvas->e_table = e_table;
    
    e_table->root = gnome_canvas_item_new (
        GNOME_CANVAS_GROUP (GNOME_CANVAS (e_table_canvas)->root),
        gnome_canvas_group_get_type (),
        "x", 0.0,
        "y", 0.0,
        NULL);

    return GNOME_CANVAS (e_table_canvas);
}
#endif

static void
table_canvas_size_allocate (GtkWidget *widget, GtkAllocation *alloc, ETable *e_table)
{
    gdouble height;
    gdouble width;
    gtk_object_get(GTK_OBJECT(e_table->group),
               "height", &height,
               NULL);
    gnome_canvas_set_scroll_region (
        GNOME_CANVAS (e_table->table_canvas),
        0, 0, alloc->width, MAX(height, alloc->height));
    width = alloc->width;
    gtk_object_set(GTK_OBJECT(e_table->group),
               "width", width,
               NULL);
}

static void
change_row (gpointer key, gpointer value, gpointer data)
{
    ETable *et = E_TABLE(data);
    gint row = GPOINTER_TO_INT(key);
    if ( e_table_group_remove(et->group, row) ) {
        e_table_group_add(et->group, row);
    }
}

static void
group_row_selection (ETableGroup *etg, int row, gboolean selected, ETable *et)
{
    gtk_signal_emit (GTK_OBJECT(et),
             et_signals [ROW_SELECTION],
             row, selected);
}

static gboolean
changed_idle (gpointer data)
{
    ETable *et = E_TABLE(data);
    if ( et->need_rebuild ) {
        gtk_object_destroy( GTK_OBJECT(et->group ) );
        et->group = e_table_group_new(GNOME_CANVAS_GROUP(et->table_canvas->root),
                          et->full_header,
                          et->header,
                          et->model,
                          e_xml_get_child_by_name(xmlDocGetRootElement(et->specification), "grouping")->childs);
        gtk_signal_connect(GTK_OBJECT(et->group), "row_selection",
                   GTK_SIGNAL_FUNC(group_row_selection), et);
        e_table_fill_table(et, et->model);
    } else if (et->need_row_changes) {
        g_hash_table_foreach(et->row_changes_list, change_row, et);
    }   
    et->need_rebuild = 0;
    et->need_row_changes = 0;
    if (et->row_changes_list)
        g_hash_table_destroy(et->row_changes_list);
    et->row_changes_list = NULL;
    et->rebuild_idle_id = 0;
    return FALSE;
}

static void
et_table_model_changed (ETableModel *model, ETable *et)
{
    et->need_rebuild = TRUE;
    if ( !et->rebuild_idle_id ) {
        et->rebuild_idle_id = g_idle_add(changed_idle, et);
    }
}

static void
et_table_row_changed (ETableModel *table_model, int row, ETable *et)
{
    if ( !et->need_rebuild ) {
        if (!et->need_row_changes) {
            et->need_row_changes = 1;
            et->row_changes_list = g_hash_table_new (g_direct_hash, g_direct_equal);
        }
        if (!g_hash_table_lookup(et->row_changes_list, GINT_TO_POINTER(row))) {
            g_hash_table_insert(et->row_changes_list, GINT_TO_POINTER(row), GINT_TO_POINTER(row + 1));
        }
    }
    if ( !et->rebuild_idle_id ) {
        et->rebuild_idle_id = g_idle_add(changed_idle, et);
    }
}

static void
et_table_cell_changed (ETableModel *table_model, int view_col, int row, ETable *et)
{
    et_table_row_changed(table_model, row, et);
}

static void
e_table_setup_table (ETable *e_table, ETableHeader *full_header, ETableHeader *header, ETableModel *model, xmlNode *xml_grouping)
{
    e_table->table_canvas = GNOME_CANVAS(e_canvas_new ());
    gtk_signal_connect (
        GTK_OBJECT (e_table->table_canvas), "size_allocate",
        GTK_SIGNAL_FUNC (table_canvas_size_allocate), e_table);
    
    gtk_widget_show (GTK_WIDGET (e_table->table_canvas));
    gtk_table_attach (
        GTK_TABLE (e_table), GTK_WIDGET (e_table->table_canvas),
        0, 1, 1, 2, GTK_FILL | GTK_EXPAND, GTK_FILL | GTK_EXPAND, 0, 0);
    
    e_table->group = e_table_group_new(GNOME_CANVAS_GROUP(e_table->table_canvas->root),
                       full_header,
                       header,
                       model,
                       xml_grouping->childs);
    gtk_signal_connect(GTK_OBJECT(e_table->group), "row_selection",
               GTK_SIGNAL_FUNC(group_row_selection), e_table);
    
    e_table->table_model_change_id = gtk_signal_connect (
        GTK_OBJECT (model), "model_changed",
        GTK_SIGNAL_FUNC (et_table_model_changed), e_table);

    e_table->table_row_change_id = gtk_signal_connect (
        GTK_OBJECT (model), "model_row_changed",
        GTK_SIGNAL_FUNC (et_table_row_changed), e_table);

    e_table->table_cell_change_id = gtk_signal_connect (
        GTK_OBJECT (model), "model_cell_changed",
        GTK_SIGNAL_FUNC (et_table_cell_changed), e_table);
}

static void
e_table_fill_table (ETable *e_table, ETableModel *model)
{
    int count;
    int i;
    count = e_table_model_row_count(model);
    gtk_object_set(GTK_OBJECT(e_table->group),
               "frozen", TRUE,
               NULL);
    for ( i = 0; i < count; i++ ) {
        e_table_group_add(e_table->group, i);
    }
    gtk_object_set(GTK_OBJECT(e_table->group),
               "frozen", FALSE,
               NULL);
}

static void
et_real_construct (ETable *e_table, ETableHeader *full_header, ETableModel *etm,
            xmlDoc *xmlSpec)
{
    xmlNode *xmlRoot;
    xmlNode *xmlColumns;
    xmlNode *xmlGrouping;
    
    GtkWidget *vscrollbar;

    GTK_TABLE (e_table)->homogeneous = FALSE;

    gtk_table_resize (GTK_TABLE (e_table), 2, 2);

    e_table->full_header = full_header;
    gtk_object_ref (GTK_OBJECT (full_header));

    e_table->model = etm;
    gtk_object_ref (GTK_OBJECT (etm));

    e_table->specification = xmlSpec;
    xmlRoot = xmlDocGetRootElement(xmlSpec);
    xmlColumns = e_xml_get_child_by_name(xmlRoot, "columns-shown");
    xmlGrouping = e_xml_get_child_by_name(xmlRoot, "grouping");
    
    gtk_widget_push_visual (gdk_rgb_get_visual ());
    gtk_widget_push_colormap (gdk_rgb_get_cmap ());

    e_table->header = e_table_make_header (e_table, full_header, xmlColumns);

    e_table_setup_header (e_table);
    e_table_setup_table (e_table, full_header, e_table->header, etm, xmlGrouping);
    e_table_fill_table (e_table, etm);

    vscrollbar = gtk_vscrollbar_new(gtk_layout_get_vadjustment(GTK_LAYOUT(e_table->table_canvas)));
    gtk_widget_show (vscrollbar);
    gtk_table_attach (
        GTK_TABLE (e_table), vscrollbar,
        1, 2, 0, 2, 0, GTK_FILL | GTK_EXPAND, 0, 0);

    gtk_widget_pop_colormap ();
    gtk_widget_pop_visual ();
}

void
e_table_construct (ETable *e_table, ETableHeader *full_header, ETableModel *etm,
           const char *spec)
{
    xmlDoc *xmlSpec;
    char *copy;
    copy = g_strdup(spec);

    xmlSpec = xmlParseMemory(copy, strlen(copy) + 1);
    et_real_construct(e_table, full_header, etm, xmlSpec);
    g_free(copy);
}

void
e_table_construct_from_spec_file (ETable *e_table, ETableHeader *full_header, ETableModel *etm,
                  const char *filename)
{
    xmlDoc *xmlSpec;

    xmlSpec = xmlParseFile(filename);
    et_real_construct(e_table, full_header, etm, xmlSpec);
}

GtkWidget *
e_table_new (ETableHeader *full_header, ETableModel *etm, const char *spec)
{
    ETable *e_table;

    e_table = gtk_type_new (e_table_get_type ());

    e_table_construct (e_table, full_header, etm, spec);
        
    return (GtkWidget *) e_table;
}

GtkWidget *
e_table_new_from_spec_file (ETableHeader *full_header, ETableModel *etm, const char *filename)
{
    ETable *e_table;

    e_table = gtk_type_new (e_table_get_type ());

    e_table_construct_from_spec_file (e_table, full_header, etm, filename);
        
    return (GtkWidget *) e_table;
}

static xmlNode *
et_build_column_spec(ETable *e_table)
{
    xmlNode *columns_shown;
    gint i;
    gint col_count;

    columns_shown = xmlNewNode(NULL, "columns-shown");

    col_count = e_table_header_count(e_table->header);
    for ( i = 0; i < col_count; i++ ) {
        gchar *text = g_strdup_printf("%d", e_table_header_index(e_table->header, i));
        xmlNewChild(columns_shown, NULL, "column", text);
        g_free(text);
    }
    if ( e_table->header->frozen_count != 0 )
        e_xml_set_integer_prop_by_name(columns_shown, "frozen_columns", e_table->header->frozen_count);
    return columns_shown;
}

static xmlNode *
et_build_grouping_spec(ETable *e_table)
{
    xmlNode *grouping;
    xmlNode *root;

    root = xmlDocGetRootElement(e_table->specification);
    grouping = xmlCopyNode(e_xml_get_child_by_name(root, "grouping"), TRUE);
    return grouping;
}

static xmlDoc *
et_build_tree (ETable *e_table)
{
    xmlDoc *doc;
    xmlNode *root;
    doc = xmlNewDoc( "1.0" );
    if ( doc == NULL )
        return NULL;
    root = xmlNewDocNode(doc, NULL, "ETableSpecification", NULL);
    xmlDocSetRootElement(doc, root);
    xmlAddChild(root, et_build_column_spec(e_table));
    xmlAddChild(root, et_build_grouping_spec(e_table));
    return doc;
}

gchar *
e_table_get_specification (ETable *e_table)
{
    xmlDoc *doc = et_build_tree (e_table);
    xmlChar *buffer;
    gint size;
    xmlDocDumpMemory(doc,
             &buffer,
             &size);
    xmlFreeDoc(doc);
    return buffer;
}

void
e_table_save_specification (ETable *e_table, gchar *filename)
{
    xmlDoc *doc = et_build_tree (e_table);
    xmlSaveFile(filename, doc);
    xmlFreeDoc(doc);
}


static void
e_table_class_init (GtkObjectClass *object_class)
{
    ETableClass *klass = E_TABLE_CLASS(object_class);
    e_table_parent_class = gtk_type_class (PARENT_TYPE);

    object_class->destroy = et_destroy;

    klass->row_selection = NULL;

    et_signals [ROW_SELECTION] =
        gtk_signal_new ("row_selection",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ETableClass, row_selection),
                gtk_marshal_NONE__INT_INT,
                GTK_TYPE_NONE, 2, GTK_TYPE_INT, GTK_TYPE_INT);
    
    gtk_object_class_add_signals (object_class, et_signals, LAST_SIGNAL);
}

E_MAKE_TYPE(e_table, "ETable", ETable, e_table_class_init, e_table_init, PARENT_TYPE);