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

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* 
 * e-tree-model.c
 * Copyright 2000, 2001, Ximian, Inc.
 *
 * Authors:
 *   Chris Lahey <clahey@ximian.com>
 *   Chris Toshok <toshok@ximian.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License, version 2, as published by the Free Software Foundation.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <config.h>

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

#include <gnome-xml/parser.h>
#include <gnome-xml/xmlmemory.h>

#include <gtk/gtksignal.h>
#include "gal/util/e-util.h"
#include "gal/util/e-xml-utils.h"
#include "e-tree-model.h"

#define ETM_CLASS(e) ((ETreeModelClass *)((GtkObject *)e)->klass)

#define PARENT_TYPE (gtk_object_get_type())

static GtkObjectClass *parent_class;

enum {
    PRE_CHANGE,
    NO_CHANGE,
    NODE_CHANGED,
    NODE_DATA_CHANGED,
    NODE_COL_CHANGED,
    NODE_INSERTED,
    NODE_REMOVED,
    NODE_DELETED,
    NODE_REQUEST_COLLAPSE,
    LAST_SIGNAL
};

static guint e_tree_model_signals [LAST_SIGNAL] = {0, };


static void
e_tree_model_class_init (GtkObjectClass *klass)
{
    ETreeModelClass *tree_class = (ETreeModelClass *) klass;

    parent_class = gtk_type_class (PARENT_TYPE);

    e_tree_model_signals [PRE_CHANGE] =
        gtk_signal_new ("pre_change",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, pre_change),
                gtk_marshal_NONE__NONE,
                GTK_TYPE_NONE, 0);

    e_tree_model_signals [NO_CHANGE] =
        gtk_signal_new ("no_change",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, no_change),
                gtk_marshal_NONE__NONE,
                GTK_TYPE_NONE, 0);

    e_tree_model_signals [NODE_CHANGED] =
        gtk_signal_new ("node_changed",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_changed),
                gtk_marshal_NONE__POINTER,
                GTK_TYPE_NONE, 1, GTK_TYPE_POINTER);

    e_tree_model_signals [NODE_DATA_CHANGED] =
        gtk_signal_new ("node_data_changed",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_data_changed),
                gtk_marshal_NONE__POINTER,
                GTK_TYPE_NONE, 1, GTK_TYPE_POINTER);

    e_tree_model_signals [NODE_COL_CHANGED] =
        gtk_signal_new ("node_col_changed",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_col_changed),
                gtk_marshal_NONE__POINTER_INT,
                GTK_TYPE_NONE, 2, GTK_TYPE_POINTER, GTK_TYPE_INT);

    e_tree_model_signals [NODE_INSERTED] =
        gtk_signal_new ("node_inserted",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_inserted),
                gtk_marshal_NONE__POINTER_POINTER,
                GTK_TYPE_NONE, 2, GTK_TYPE_POINTER, GTK_TYPE_POINTER);

    e_tree_model_signals [NODE_REMOVED] =
        gtk_signal_new ("node_removed",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_removed),
                e_marshal_NONE__POINTER_POINTER_INT,
                GTK_TYPE_NONE, 3, GTK_TYPE_POINTER, GTK_TYPE_POINTER, GTK_TYPE_INT);

    e_tree_model_signals [NODE_DELETED] =
        gtk_signal_new ("node_deleted",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_deleted),
                gtk_marshal_NONE__POINTER,
                GTK_TYPE_NONE, 1, GTK_TYPE_POINTER);

    e_tree_model_signals [NODE_REQUEST_COLLAPSE] =
        gtk_signal_new ("node_request_collapse",
                GTK_RUN_LAST,
                E_OBJECT_CLASS_TYPE (klass),
                GTK_SIGNAL_OFFSET (ETreeModelClass, node_request_collapse),
                gtk_marshal_NONE__POINTER,
                GTK_TYPE_NONE, 1, GTK_TYPE_POINTER);

    E_OBJECT_CLASS_ADD_SIGNALS (klass, e_tree_model_signals, LAST_SIGNAL);

    tree_class->get_root              = NULL;

    tree_class->get_parent            = NULL;
    tree_class->get_first_child       = NULL;
    tree_class->get_last_child        = NULL;
    tree_class->get_next              = NULL;
    tree_class->get_prev              = NULL;

    tree_class->is_root               = NULL;
    tree_class->is_expandable         = NULL;
    tree_class->get_children          = NULL;
    tree_class->depth                 = NULL;

    tree_class->icon_at               = NULL;

    tree_class->get_expanded_default  = NULL;
    tree_class->column_count          = NULL;

    tree_class->has_save_id           = NULL;
    tree_class->get_save_id           = NULL;
    tree_class->has_get_node_by_id    = NULL;
    tree_class->get_node_by_id        = NULL;

    tree_class->has_change_pending    = NULL;

    tree_class->value_at              = NULL;
    tree_class->set_value_at          = NULL;
    tree_class->is_editable           = NULL;

    tree_class->duplicate_value       = NULL;
    tree_class->free_value            = NULL;
    tree_class->initialize_value      = NULL;
    tree_class->value_is_empty        = NULL;
    tree_class->value_to_string       = NULL;

    tree_class->pre_change            = NULL;
    tree_class->no_change             = NULL;
    tree_class->node_changed          = NULL;
    tree_class->node_data_changed     = NULL;
    tree_class->node_col_changed      = NULL;
    tree_class->node_inserted         = NULL;
    tree_class->node_removed          = NULL;
    tree_class->node_deleted          = NULL;
    tree_class->node_request_collapse = NULL;
}

static void
e_tree_init (GtkObject *object)
{
}

E_MAKE_TYPE(e_tree_model, "ETreeModel", ETreeModel, e_tree_model_class_init, e_tree_init, PARENT_TYPE)


/* signals */

/**
 * e_tree_model_node_changed:
 * @tree_model: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
void
e_tree_model_pre_change  (ETreeModel *tree_model)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [PRE_CHANGE]);
}

/**
 * e_tree_model_node_changed:
 * @tree_model: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
void
e_tree_model_no_change  (ETreeModel *tree_model)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NO_CHANGE]);
}

/**
 * e_tree_model_node_changed:
 * @tree_model: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
void
e_tree_model_node_changed  (ETreeModel *tree_model, ETreePath node)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_CHANGED], node);
}

/**
 * e_tree_model_node_data_changed:
 * @tree_model: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
void
e_tree_model_node_data_changed  (ETreeModel *tree_model, ETreePath node)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_DATA_CHANGED], node);
}

/**
 * e_tree_model_node_col_changed:
 * @tree_model: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
void
e_tree_model_node_col_changed  (ETreeModel *tree_model, ETreePath node, int col)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_COL_CHANGED], node, col);
}

/**
 * e_tree_model_node_inserted:
 * @tree_model: 
 * @parent_node: 
 * @inserted_node: 
 * 
 * 
 **/
void
e_tree_model_node_inserted (ETreeModel *tree_model,
                ETreePath parent_node,
                ETreePath inserted_node)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));

    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_INSERTED],
             parent_node, inserted_node);
}

/**
 * e_tree_model_node_removed:
 * @tree_model: 
 * @parent_node: 
 * @removed_node: 
 * 
 * 
 **/
void
e_tree_model_node_removed  (ETreeModel *tree_model, ETreePath parent_node, ETreePath removed_node, int old_position)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_REMOVED],
             parent_node, removed_node, old_position);
}

/**
 * e_tree_model_node_deleted:
 * @tree_model: 
 * @deleted_node: 
 * 
 * 
 **/
void
e_tree_model_node_deleted  (ETreeModel *tree_model, ETreePath deleted_node)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_DELETED],
             deleted_node);
}

/**
 * e_tree_model_node_request_collapse:
 * @tree_model: 
 * @collapsed_node: 
 * 
 * 
 **/
void
e_tree_model_node_request_collapse  (ETreeModel *tree_model, ETreePath collapsed_node)
{
    g_return_if_fail (tree_model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (tree_model));
    
    gtk_signal_emit (GTK_OBJECT (tree_model),
             e_tree_model_signals [NODE_REQUEST_COLLAPSE],
             collapsed_node);
}



/**
 * e_tree_model_new
 *
 * XXX docs here.
 *
 * return values: a newly constructed ETreeModel.
 */
ETreeModel *
e_tree_model_new ()
{
    ETreeModel *et;

    et = gtk_type_new (e_tree_model_get_type ());

    return et;
}

/**
 * e_tree_model_get_root
 * @etree: the ETreeModel of which we want the root node.
 *
 * Accessor for the root node of @etree.
 *
 * return values: the ETreePath corresponding to the root node.
 */
ETreePath 
e_tree_model_get_root (ETreeModel *etree)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_root)
        return ETM_CLASS(etree)->get_root(etree);
    else
        return NULL;
}

/**
 * e_tree_model_node_get_parent:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
ETreePath 
e_tree_model_node_get_parent (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail(etree != NULL, NULL);
    if (ETM_CLASS(etree)->get_parent)
        return ETM_CLASS(etree)->get_parent(etree, node);
    else
        return NULL;
}

/**
 * e_tree_model_node_get_first_child:
 * @etree: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
ETreePath 
e_tree_model_node_get_first_child (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_first_child)
        return ETM_CLASS(etree)->get_first_child(etree, node);
    else
        return NULL;
}

/**
 * e_tree_model_node_get_last_child:
 * @etree: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
ETreePath 
e_tree_model_node_get_last_child (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_last_child)
        return ETM_CLASS(etree)->get_last_child(etree, node);
    else
        return NULL;
}


/**
 * e_tree_model_node_get_next:
 * @etree: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
ETreePath 
e_tree_model_node_get_next (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_next)
        return ETM_CLASS(etree)->get_next(etree, node);
    else
        return NULL;
}

/**
 * e_tree_model_node_get_prev:
 * @etree: 
 * @node: 
 * 
 * 
 * 
 * Return value: 
 **/
ETreePath 
e_tree_model_node_get_prev (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_prev)
        return ETM_CLASS(etree)->get_prev(etree, node);
    else
        return NULL;
}

/**
 * e_tree_model_node_is_root:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
gboolean
e_tree_model_node_is_root (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail(etree != NULL, FALSE);

    if (ETM_CLASS(etree)->is_root)
        return ETM_CLASS(etree)->is_root(etree, node);
    else
        return FALSE;
}

/**
 * e_tree_model_node_is_expandable:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
gboolean
e_tree_model_node_is_expandable (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail(etree != NULL, FALSE);

    if (ETM_CLASS(etree)->is_expandable)
        return ETM_CLASS(etree)->is_expandable(etree, node);
    else
        return FALSE;
}

guint
e_tree_model_node_get_children (ETreeModel *etree, ETreePath node, ETreePath **nodes)
{
    g_return_val_if_fail(etree != NULL, 0);
    if (ETM_CLASS(etree)->get_children)
        return ETM_CLASS(etree)->get_children (etree, node, nodes);
    else
        return 0;
}

/**
 * e_tree_model_node_depth:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
guint
e_tree_model_node_depth (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, 0);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), 0);

    if (ETM_CLASS(etree)->depth)
        return ETM_CLASS(etree)->depth(etree, node);
    else
        return 0;
}

/**
 * e_tree_model_icon_at
 * @etree: The ETreeModel.
 * @path: The ETreePath to the node we're getting the icon of.
 *
 * XXX docs here.
 *
 * return values: the GdkPixbuf associated with this node.
 */
GdkPixbuf *
e_tree_model_icon_at (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->icon_at)
        return ETM_CLASS(etree)->icon_at (etree, node);
    else
        return NULL;
}

/**
 * e_tree_model_get_expanded_default
 * @etree: The ETreeModel.
 *
 * XXX docs here.
 *
 * return values: Whether nodes should be expanded by default.
 */
gboolean
e_tree_model_get_expanded_default (ETreeModel *etree)
{
    g_return_val_if_fail (etree != NULL, FALSE);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), FALSE);

    if (ETM_CLASS(etree)->get_expanded_default)
        return ETM_CLASS(etree)->get_expanded_default (etree);
    else
        return FALSE;
}

/**
 * e_tree_model_column_count
 * @etree: The ETreeModel.
 *
 * XXX docs here.
 *
 * return values: The number of columns
 */
gint
e_tree_model_column_count (ETreeModel *etree)
{
    g_return_val_if_fail (etree != NULL, 0);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), 0);

    if (ETM_CLASS(etree)->column_count)
        return ETM_CLASS(etree)->column_count (etree);
    else
        return 0;
}

/**
 * e_tree_model_has_save_id
 * @etree: The ETreeModel.
 *
 * XXX docs here.
 *
 * return values: Whether this tree has valid save id data.
 */
gboolean
e_tree_model_has_save_id (ETreeModel *etree)
{
    g_return_val_if_fail (etree != NULL, FALSE);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), FALSE);

    if (ETM_CLASS(etree)->has_save_id)
        return ETM_CLASS(etree)->has_save_id (etree);
    else
        return FALSE;
}

/**
 * e_tree_model_get_save_id
 * @etree: The ETreeModel.
 * @node: The ETreePath.
 *
 * XXX docs here.
 *
 * return values: The save id for this path.
 */
gchar *
e_tree_model_get_save_id (ETreeModel *etree, ETreePath node)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_save_id)
        return ETM_CLASS(etree)->get_save_id (etree, node);
    else
        return NULL;
}

/**
 * e_tree_model_has_get_node_by_id
 * @etree: The ETreeModel.
 *
 * XXX docs here.
 *
 * return values: Whether this tree can quickly get a node from its save id.
 */
gboolean
e_tree_model_has_get_node_by_id (ETreeModel *etree)
{
    g_return_val_if_fail (etree != NULL, FALSE);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), FALSE);

    if (ETM_CLASS(etree)->has_get_node_by_id)
        return ETM_CLASS(etree)->has_get_node_by_id (etree);
    else
        return FALSE;
}

/**
 * e_tree_model_get_node_by_id
 * @etree: The ETreeModel.
 * @node: The ETreePath.
 *
 * get_node_by_id(get_save_id(node)) should be the original node.
 * Likewise if get_node_by_id is not NULL, then
 * get_save_id(get_node_by_id(string)) should be a copy of the
 * original string.
 *
 * return values: The path for this save id.
 */
ETreePath
e_tree_model_get_node_by_id (ETreeModel *etree, const char *save_id)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->get_node_by_id)
        return ETM_CLASS(etree)->get_node_by_id (etree, save_id);
    else
        return NULL;
}

/**
 * e_tree_model_has_change_pending
 * @etree: The ETreeModel.
 *
 * XXX docs here.
 *
 * return values: Whether this tree has valid save id data.
 */
gboolean
e_tree_model_has_change_pending (ETreeModel *etree)
{
    g_return_val_if_fail (etree != NULL, FALSE);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), FALSE);

    if (ETM_CLASS(etree)->has_change_pending)
        return ETM_CLASS(etree)->has_change_pending (etree);
    else
        return FALSE;
}

/**
 * e_tree_model_icon_of_node
 * @etree: The ETreeModel.
 * @path: The ETreePath to the node we're getting the icon of.
 *
 * XXX docs here.
 *
 * return values: the GdkPixbuf associated with this node.
 */
void *
e_tree_model_value_at (ETreeModel *etree, ETreePath node, int col)
{
    g_return_val_if_fail (etree != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (etree), NULL);

    if (ETM_CLASS(etree)->value_at)
        return ETM_CLASS(etree)->value_at (etree, node, col);
    else
        return NULL;
}

/**
 * e_tree_model_icon_of_node
 * @etree: The ETreeModel.
 * @path: The ETreePath to the node we're getting the icon of.
 *
 * XXX docs here.
 *
 * return values: the GdkPixbuf associated with this node.
 */
void
e_tree_model_set_value_at (ETreeModel *etree, ETreePath node, int col, const void *val)
{
    g_return_if_fail (etree != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (etree));

    if (ETM_CLASS(etree)->set_value_at)
        ETM_CLASS(etree)->set_value_at (etree, node, col, val);
}

/**
 * e_tree_model_node_is_editable:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
gboolean
e_tree_model_node_is_editable (ETreeModel *etree, ETreePath node, int col)
{
    g_return_val_if_fail(etree != NULL, FALSE);

    if (ETM_CLASS(etree)->is_editable)
        return ETM_CLASS(etree)->is_editable(etree, node, col);
    else
        return FALSE;
}

/**
 * e_tree_model_duplicate_value:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
void *
e_tree_model_duplicate_value (ETreeModel *etree, int col, const void *value)
{
    g_return_val_if_fail(etree != NULL, NULL);

    if (ETM_CLASS(etree)->duplicate_value)
        return ETM_CLASS(etree)->duplicate_value(etree, col, value);
    else
        return NULL;
}

/**
 * e_tree_model_free_value:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
void
e_tree_model_free_value (ETreeModel *etree, int col, void *value)
{
    g_return_if_fail(etree != NULL);

    if (ETM_CLASS(etree)->free_value)
        ETM_CLASS(etree)->free_value(etree, col, value);
}

/**
 * e_tree_model_initialize_value:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
void *
e_tree_model_initialize_value (ETreeModel *etree, int col)
{
    g_return_val_if_fail(etree != NULL, NULL);

    if (ETM_CLASS(etree)->initialize_value)
        return ETM_CLASS(etree)->initialize_value(etree, col);
    else
        return NULL;
}

/**
 * e_tree_model_value_is_empty:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
gboolean
e_tree_model_value_is_empty (ETreeModel *etree, int col, const void *value)
{
    g_return_val_if_fail(etree != NULL, TRUE);

    if (ETM_CLASS(etree)->value_is_empty)
        return ETM_CLASS(etree)->value_is_empty(etree, col, value);
    else
        return TRUE;
}

/**
 * e_tree_model_value_to_string:
 * @etree: 
 * @path: 
 * 
 * 
 * 
 * Return value: 
 **/
char *
e_tree_model_value_to_string (ETreeModel *etree, int col, const void *value)
{
    g_return_val_if_fail(etree != NULL, g_strdup(""));

    if (ETM_CLASS(etree)->value_to_string)
        return ETM_CLASS(etree)->value_to_string(etree, col, value);
    else
        return g_strdup("");
}

/**
 * e_tree_model_node_traverse:
 * @model: 
 * @path: 
 * @func: 
 * @data: 
 * 
 * 
 **/
void
e_tree_model_node_traverse (ETreeModel *model, ETreePath path, ETreePathFunc func, gpointer data)
{
    ETreePath child;

    g_return_if_fail (model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (model));
    g_return_if_fail (path != NULL);

    child = e_tree_model_node_get_first_child (model, path);

    while (child) {
        ETreePath next_child;

        next_child = e_tree_model_node_get_next (model, child);
        e_tree_model_node_traverse (model, child, func, data);
        if (func (model, child, data) == TRUE)
            return;

        child = next_child;
    }
}

/**
 * e_tree_model_node_traverse_preorder:
 * @model: 
 * @path: 
 * @func: 
 * @data: 
 * 
 * 
 **/
void
e_tree_model_node_traverse_preorder (ETreeModel *model, ETreePath path, ETreePathFunc func, gpointer data)
{
    ETreePath child;

    g_return_if_fail (model != NULL);
    g_return_if_fail (E_IS_TREE_MODEL (model));
    g_return_if_fail (path != NULL);

    child = e_tree_model_node_get_first_child (model, path);

    while (child) {
        ETreePath next_child;

        if (func (model, child, data) == TRUE)
            return;

        next_child = e_tree_model_node_get_next (model, child);
        e_tree_model_node_traverse_preorder (model, child, func, data);

        child = next_child;
    }
}

/**
 * e_tree_model_node_traverse_preorder:
 * @model: 
 * @path: 
 * @func: 
 * @data: 
 * 
 * 
 **/
static ETreePath
e_tree_model_node_real_traverse (ETreeModel *model, ETreePath path, ETreePath end_path, gboolean forward_direction, ETreePathFunc func, gpointer data)
{
    ETreePath child;

    g_return_val_if_fail (model != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (model), NULL);
    g_return_val_if_fail (path != NULL, NULL);

    if (forward_direction)
        child = e_tree_model_node_get_first_child (model, path);
    else
        child = e_tree_model_node_get_last_child (model, path);

    while (child) {
        ETreePath result;

        if (forward_direction && (child == end_path || func (model, child, data)))
            return child;

        if ((result = e_tree_model_node_real_traverse (model, child, end_path, forward_direction, func, data)))
            return result;

        if (!forward_direction && (child == end_path || func (model, child, data)))
            return child;

        if (forward_direction)
            child = e_tree_model_node_get_next (model, child);
        else
            child = e_tree_model_node_get_prev (model, child);
    }
    return NULL;
}

/**
 * e_tree_model_node_traverse_preorder:
 * @model: 
 * @path: 
 * @func: 
 * @data: 
 * 
 * 
 **/
ETreePath
e_tree_model_node_find (ETreeModel *model, ETreePath path, ETreePath end_path, gboolean forward_direction, ETreePathFunc func, gpointer data)
{
    ETreePath result;
    ETreePath next;

    g_return_val_if_fail (model != NULL, NULL);
    g_return_val_if_fail (E_IS_TREE_MODEL (model), NULL);

    /* Just search the whole tree in this case. */
    if (path == NULL) {
        ETreePath root;
        root = e_tree_model_get_root (model);

        if (forward_direction && (end_path == root || func (model, root, data)))
            return root;

        if ((result = e_tree_model_node_real_traverse (model, root, end_path, forward_direction, func, data)))
            return result;

        if (!forward_direction && (end_path == root || func (model, root, data)))
            return root;

        return NULL;
    }

    while (1) {

        if (forward_direction) {
            if ((result = e_tree_model_node_real_traverse (model, path, end_path, forward_direction, func, data)))
                return result;
            next = e_tree_model_node_get_next (model, path);
        } else {
            next = e_tree_model_node_get_prev (model, path);
            if (next && (result = e_tree_model_node_real_traverse (model, next, end_path, forward_direction, func, data)))
                return result;
        }

        while (next == NULL) {
            path = e_tree_model_node_get_parent (model, path);

            if (path == NULL)
                return NULL;

            if (forward_direction)
                next = e_tree_model_node_get_next (model, path);
            else
                next = path;
        }

        if (end_path == next || func (model, next, data))
            return next;

        path = next;
    }
}