/* gtktreemodel.c

 * Copyright (C) 2000  Red Hat, Inc.,  Jonathan Blandford <jrb@redhat.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * 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 <stdlib.h>

#include <string.h>

#include <glib.h>

#include <glib/gprintf.h>

#include <gobject/gvaluecollector.h>

#include "gtktreemodel.h"

#include "gtktreeview.h"

#include "gtktreeprivate.h"

#include "gtkmarshalers.h"

#include "gtkintl.h"

#include "gtkalias.h"

#define INITIALIZE_TREE_ITER(Iter) \

    G_STMT_START{ \

      (Iter)->stamp = 0; \

      (Iter)->user_data  = NULL; \

      (Iter)->user_data2 = NULL; \

      (Iter)->user_data3 = NULL; \

    }G_STMT_END

#define ROW_REF_DATA_STRING "gtk-tree-row-refs"

enum {

  ROW_CHANGED,

  ROW_INSERTED,

  ROW_HAS_CHILD_TOGGLED,

  ROW_DELETED,

  ROWS_REORDERED,

  LAST_SIGNAL

};

static guint tree_model_signals[LAST_SIGNAL] = { 0 };

struct _GtkTreePath

{

  gint depth;

  gint *indices;

};

typedef struct

{

  GSList *list;

} RowRefList;

static void      gtk_tree_model_base_init   (gpointer           g_class);

/* custom closures */

static void      row_inserted_marshal       (GClosure          *closure,

                                             GValue /* out */  *return_value,

                                             guint              n_param_value,

                                             const GValue      *param_values,

                                             gpointer           invocation_hint,

                                             gpointer           marshal_data);

static void      row_deleted_marshal        (GClosure          *closure,

                                             GValue /* out */  *return_value,

                                             guint              n_param_value,

                                             const GValue      *param_values,

                                             gpointer           invocation_hint,

                                             gpointer           marshal_data);

static void      rows_reordered_marshal     (GClosure          *closure,

                                             GValue /* out */  *return_value,

                                             guint              n_param_value,

                                             const GValue      *param_values,

                                             gpointer           invocation_hint,

                                             gpointer           marshal_data);

static void      gtk_tree_row_ref_inserted  (RowRefList        *refs,

                                             GtkTreePath       *path,

                                             GtkTreeIter       *iter);

static void      gtk_tree_row_ref_deleted   (RowRefList        *refs,

                                             GtkTreePath       *path);

static void      gtk_tree_row_ref_reordered (RowRefList        *refs,

                                             GtkTreePath       *path,

                                             GtkTreeIter       *iter,

                                             gint              *new_order);

GType

gtk_tree_model_get_type (void)

{

  static GType tree_model_type = 0;

  if (! tree_model_type)

    {

      const GTypeInfo tree_model_info =

      {

        sizeof (GtkTreeModelIface), /* class_size */

	gtk_tree_model_base_init,   /* base_init */

	NULL,		/* base_finalize */

	NULL,

	NULL,		/* class_finalize */

	NULL,		/* class_data */

	0,

	0,              /* n_preallocs */

	NULL

      };

      tree_model_type =

	g_type_register_static (G_TYPE_INTERFACE, I_("GtkTreeModel"),

				&tree_model_info, 0);

      g_type_interface_add_prerequisite (tree_model_type, G_TYPE_OBJECT);

    }

  return tree_model_type;

}

static void

gtk_tree_model_base_init (gpointer g_class)

{

  static gboolean initialized = FALSE;

  GClosure *closure;

  if (! initialized)

    {

      GType row_inserted_params[2];

      GType row_deleted_params[1];

      GType rows_reordered_params[3];

      row_inserted_params[0] = GTK_TYPE_TREE_PATH | G_SIGNAL_TYPE_STATIC_SCOPE;

      row_inserted_params[1] = GTK_TYPE_TREE_ITER;

      row_deleted_params[0] = GTK_TYPE_TREE_PATH | G_SIGNAL_TYPE_STATIC_SCOPE;

      rows_reordered_params[0] = GTK_TYPE_TREE_PATH | G_SIGNAL_TYPE_STATIC_SCOPE;

      rows_reordered_params[1] = GTK_TYPE_TREE_ITER;

      rows_reordered_params[2] = G_TYPE_POINTER;

      /**

       * GtkTreeModel::row-changed:

       * @tree_model: the #GtkTreeModel on which the signal is emitted

       * @path: a #GtkTreePath identifying the changed row

       * @iter: a valid #GtkTreeIter pointing to the changed row

       *

       * This signal is emitted when a row in the model has changed.

       */

      tree_model_signals[ROW_CHANGED] =

        g_signal_new (I_("row-changed"),

                      GTK_TYPE_TREE_MODEL,

                      G_SIGNAL_RUN_LAST, 

                      G_STRUCT_OFFSET (GtkTreeModelIface, row_changed),

                      NULL, NULL,

                      _gtk_marshal_VOID__BOXED_BOXED,

                      G_TYPE_NONE, 2,

                      GTK_TYPE_TREE_PATH | G_SIGNAL_TYPE_STATIC_SCOPE,

                      GTK_TYPE_TREE_ITER);

      /* We need to get notification about structure changes

       * to update row references., so instead of using the

       * standard g_signal_new() with an offset into our interface

       * structure, we use a customs closures for the class

       * closures (default handlers) that first update row references

       * and then calls the function from the interface structure.

       *

       * The reason we don't simply update the row references from

       * the wrapper functions (gtk_tree_model_row_inserted(), etc.)

       * is to keep proper ordering with respect to signal handlers

       * connected normally and after.

       */

      /**

       * GtkTreeModel::row-inserted:

       * @tree_model: the #GtkTreeModel on which the signal is emitted

       * @path: a #GtkTreePath identifying the new row

       * @iter: a valid #GtkTreeIter pointing to the new row

       *

       * This signal is emitted when a new row has been inserted in the model.

       *

       * Note that the row may still be empty at this point, since

       * it is a common pattern to first insert an empty row, and 

       * then fill it with the desired values.

       */

      closure = g_closure_new_simple (sizeof (GClosure), NULL);

      g_closure_set_marshal (closure, row_inserted_marshal);

      tree_model_signals[ROW_INSERTED] =

        g_signal_newv (I_("row-inserted"),

                       GTK_TYPE_TREE_MODEL,

                       G_SIGNAL_RUN_FIRST,

                       closure,

                       NULL, NULL,

                       _gtk_marshal_VOID__BOXED_BOXED,

                       G_TYPE_NONE, 2,

                       row_inserted_params);

      /**

       * GtkTreeModel::row-has-child-toggled:

       * @tree_model: the #GtkTreeModel on which the signal is emitted

       * @path: a #GtkTreePath identifying the row

       * @iter: a valid #GtkTreeIter pointing to the row

       *

       * This signal is emitted when a row has gotten the first child row or lost

       * its last child row.

       */

      tree_model_signals[ROW_HAS_CHILD_TOGGLED] =

        g_signal_new (I_("row-has-child-toggled"),

                      GTK_TYPE_TREE_MODEL,

                      G_SIGNAL_RUN_LAST,

                      G_STRUCT_OFFSET (GtkTreeModelIface, row_has_child_toggled),

                      NULL, NULL,

                      _gtk_marshal_VOID__BOXED_BOXED,

                      G_TYPE_NONE, 2,

                      GTK_TYPE_TREE_PATH | G_SIGNAL_TYPE_STATIC_SCOPE,

                      GTK_TYPE_TREE_ITER);

      /**

       * GtkTreeModel::row-deleted:

       * @tree_model: the #GtkTreeModel on which the signal is emitted

       * @path: a #GtkTreePath identifying the row

       *

       * This signal is emitted when a row has been deleted.

       *

       * Note that no iterator is passed to the signal handler,

       * since the row is already deleted.

       *

       * This should be called by models after a row has been removed.

       * The location pointed to by @path should be the location that

       * the row previously was at. It may not be a valid location anymore.

       */

      closure = g_closure_new_simple (sizeof (GClosure), NULL);

      g_closure_set_marshal (closure, row_deleted_marshal);

      tree_model_signals[ROW_DELETED] =

        g_signal_newv (I_("row-deleted"),

                       GTK_TYPE_TREE_MODEL,

                       G_SIGNAL_RUN_FIRST,

                       closure,

                       NULL, NULL,

                       _gtk_marshal_VOID__BOXED,

                       G_TYPE_NONE, 1,

                       row_deleted_params);

      /**

       * GtkTreeModel::rows-reordered:

       * @tree_model: the #GtkTreeModel on which the signal is emitted

       * @path: a #GtkTreePath identifying the tree node whose children

       *        have been reordered

       * @iter: a valid #GtkTreeIter pointing to the node whose 

       * @new_order: an array of integers mapping the current position of

       *             each child to its old position before the re-ordering,

       *             i.e. @new_order<literal>[newpos] = oldpos</literal>.

       *

       * This signal is emitted when the children of a node in the #GtkTreeModel

       * have been reordered. 

       *

       * Note that this signal is <emphasis>not</emphasis> emitted

       * when rows are reordered by DND, since this is implemented

       * by removing and then reinserting the row.

       */

      closure = g_closure_new_simple (sizeof (GClosure), NULL);

      g_closure_set_marshal (closure, rows_reordered_marshal);

      tree_model_signals[ROWS_REORDERED] =

        g_signal_newv (I_("rows-reordered"),

                       GTK_TYPE_TREE_MODEL,

                       G_SIGNAL_RUN_FIRST,

                       closure,

                       NULL, NULL,

                       _gtk_marshal_VOID__BOXED_BOXED_POINTER,

                       G_TYPE_NONE, 3,

                       rows_reordered_params);

      initialized = TRUE;

    }

}

static void

row_inserted_marshal (GClosure          *closure,

                      GValue /* out */  *return_value,

                      guint              n_param_values,

                      const GValue      *param_values,

                      gpointer           invocation_hint,

                      gpointer           marshal_data)

{

  GtkTreeModelIface *iface;

  void (* row_inserted_callback) (GtkTreeModel *tree_model,

                                  GtkTreePath *path,

                                  GtkTreeIter *iter) = NULL;

  GObject *model = g_value_get_object (param_values + 0);

  GtkTreePath *path = (GtkTreePath *)g_value_get_boxed (param_values + 1);

  GtkTreeIter *iter = (GtkTreeIter *)g_value_get_boxed (param_values + 2);

  /* first, we need to update internal row references */

  gtk_tree_row_ref_inserted ((RowRefList *)g_object_get_data (model, ROW_REF_DATA_STRING),

                             path, iter);

  /* fetch the interface ->row_inserted implementation */

  iface = GTK_TREE_MODEL_GET_IFACE (model);

  row_inserted_callback = G_STRUCT_MEMBER (gpointer, iface,

                              G_STRUCT_OFFSET (GtkTreeModelIface,

                                               row_inserted));

  /* Call that default signal handler, it if has been set */                                                         

  if (row_inserted_callback)

    row_inserted_callback (GTK_TREE_MODEL (model), path, iter);

}

static void

row_deleted_marshal (GClosure          *closure,

                     GValue /* out */  *return_value,

                     guint              n_param_values,

                     const GValue      *param_values,

                     gpointer           invocation_hint,

                     gpointer           marshal_data)

{

  GtkTreeModelIface *iface;

  void (* row_deleted_callback) (GtkTreeModel *tree_model,

                                 GtkTreePath  *path) = NULL;                                 

  GObject *model = g_value_get_object (param_values + 0);

  GtkTreePath *path = (GtkTreePath *)g_value_get_boxed (param_values + 1);

  /* first, we need to update internal row references */

  gtk_tree_row_ref_deleted ((RowRefList *)g_object_get_data (model, ROW_REF_DATA_STRING),

                            path);

  /* fetch the interface ->row_deleted implementation */

  iface = GTK_TREE_MODEL_GET_IFACE (model);

  row_deleted_callback = G_STRUCT_MEMBER (gpointer, iface,

                              G_STRUCT_OFFSET (GtkTreeModelIface,

                                               row_deleted));

  /* Call that default signal handler, it if has been set */

  if (row_deleted_callback)

    row_deleted_callback (GTK_TREE_MODEL (model), path);

}

static void

rows_reordered_marshal (GClosure          *closure,

                        GValue /* out */  *return_value,

                        guint              n_param_values,

                        const GValue      *param_values,

                        gpointer           invocation_hint,

                        gpointer           marshal_data)

{

  GtkTreeModelIface *iface;

  void (* rows_reordered_callback) (GtkTreeModel *tree_model,

                                    GtkTreePath  *path,

                                    GtkTreeIter  *iter,

                                    gint         *new_order);

  GObject *model = g_value_get_object (param_values + 0);

  GtkTreePath *path = (GtkTreePath *)g_value_get_boxed (param_values + 1);

  GtkTreeIter *iter = (GtkTreeIter *)g_value_get_boxed (param_values + 2);

  gint *new_order = (gint *)g_value_get_pointer (param_values + 3);

  /* first, we need to update internal row references */

  gtk_tree_row_ref_reordered ((RowRefList *)g_object_get_data (model, ROW_REF_DATA_STRING),

                              path, iter, new_order);

  /* fetch the interface ->rows_reordered implementation */

  iface = GTK_TREE_MODEL_GET_IFACE (model);

  rows_reordered_callback = G_STRUCT_MEMBER (gpointer, iface,

                              G_STRUCT_OFFSET (GtkTreeModelIface,

                                               rows_reordered));

  /* Call that default signal handler, it if has been set */

  if (rows_reordered_callback)

    rows_reordered_callback (GTK_TREE_MODEL (model), path, iter, new_order);

}

/**

 * gtk_tree_path_new:

 *

 * Creates a new #GtkTreePath.  This structure refers to a row.

 *

 * Return value: A newly created #GtkTreePath.

 **/

/* GtkTreePath Operations */

GtkTreePath *

gtk_tree_path_new (void)

{

  GtkTreePath *retval;

  retval = g_slice_new (GtkTreePath);

  retval->depth = 0;

  retval->indices = NULL;

  return retval;

}

/**

 * gtk_tree_path_new_from_string:

 * @path: The string representation of a path.

 *

 * Creates a new #GtkTreePath initialized to @path.  @path is expected to be a

 * colon separated list of numbers.  For example, the string "10:4:0" would

 * create a path of depth 3 pointing to the 11th child of the root node, the 5th

 * child of that 11th child, and the 1st child of that 5th child.  If an invalid

 * path string is passed in, %NULL is returned.

 *

 * Return value: A newly-created #GtkTreePath, or %NULL

 **/

GtkTreePath *

gtk_tree_path_new_from_string (const gchar *path)

{

  GtkTreePath *retval;

  const gchar *orig_path = path;

  gchar *ptr;

  gint i;

  g_return_val_if_fail (path != NULL, NULL);

  g_return_val_if_fail (*path != '\000', NULL);

  retval = gtk_tree_path_new ();

  while (1)

    {

      i = strtol (path, &ptr, 10);

      if (i < 0)

	{

	  g_warning (G_STRLOC ": Negative numbers in path %s passed to gtk_tree_path_new_from_string", orig_path);

	  gtk_tree_path_free (retval);

	  return NULL;

	}

      gtk_tree_path_append_index (retval, i);

      if (*ptr == '\000')

	break;

      if (ptr == path || *ptr != ':')

	{

	  g_warning (G_STRLOC ": Invalid path %s passed to gtk_tree_path_new_from_string", orig_path);

	  gtk_tree_path_free (retval);

	  return NULL;

	}

      path = ptr + 1;

    }

  return retval;

}

/**

 * gtk_tree_path_new_from_indices:

 * @first_index: first integer

 * @varargs: list of integers terminated by -1

 *

 * Creates a new path with @first_index and @varargs as indices.

 *

 * Return value: A newly created #GtkTreePath.

 *

 * Since: 2.2

 **/

GtkTreePath *

gtk_tree_path_new_from_indices (gint first_index,

				...)

{

  int arg;

  va_list args;

  GtkTreePath *path;

  path = gtk_tree_path_new ();

  va_start (args, first_index);

  arg = first_index;

  while (arg != -1)

    {

      gtk_tree_path_append_index (path, arg);

      arg = va_arg (args, gint);

    }

  va_end (args);

  return path;

}

/**

 * gtk_tree_path_to_string:

 * @path: A #GtkTreePath

 *

 * Generates a string representation of the path.  This string is a ':'

 * separated list of numbers.  For example, "4:10:0:3" would be an acceptable return value for this string.

 *

 * Return value: A newly-allocated string.  Must be freed with g_free().

 **/

gchar *

gtk_tree_path_to_string (GtkTreePath *path)

{

  gchar *retval, *ptr, *end;

  gint i, n;

  g_return_val_if_fail (path != NULL, NULL);

  if (path->depth == 0)

    return NULL;

  n = path->depth * 12;

  ptr = retval = g_new0 (gchar, n);

  end = ptr + n;

  g_snprintf (retval, end - ptr, "%d", path->indices[0]);

  while (*ptr != '\000') 

    ptr++;

  for (i = 1; i < path->depth; i++)

    {

      g_snprintf (ptr, end - ptr, ":%d", path->indices[i]);

      while (*ptr != '\000')

	ptr++;

    }

  return retval;

}

/**

 * gtk_tree_path_new_first:

 *

 * Creates a new #GtkTreePath.  The string representation of this path is "0"

 *

 * Return value: A new #GtkTreePath.

 **/

GtkTreePath *

gtk_tree_path_new_first (void)

{

  GtkTreePath *retval;

  retval = gtk_tree_path_new ();

  gtk_tree_path_append_index (retval, 0);

  return retval;

}

/**

 * gtk_tree_path_append_index:

 * @path: A #GtkTreePath.

 * @index_: The index.

 *

 * Appends a new index to a path.  As a result, the depth of the path is

 * increased.

 **/

void

gtk_tree_path_append_index (GtkTreePath *path,

			    gint         index)

{

  g_return_if_fail (path != NULL);

  g_return_if_fail (index >= 0);

  path->depth += 1;

  path->indices = g_realloc (path->indices, path->depth * sizeof(gint));

  path->indices[path->depth - 1] = index;

}

/**

 * gtk_tree_path_prepend_index:

 * @path: A #GtkTreePath.

 * @index_: The index.

 *

 * Prepends a new index to a path.  As a result, the depth of the path is

 * increased.

 **/

void

gtk_tree_path_prepend_index (GtkTreePath *path,

			     gint       index)

{

  gint *new_indices;

  (path->depth)++;

  new_indices = g_new (gint, path->depth);

  if (path->indices == NULL)

    {

      path->indices = new_indices;

      path->indices[0] = index;

      return;

    }

  memcpy (new_indices + 1, path->indices, (path->depth - 1)*sizeof (gint));

  g_free (path->indices);

  path->indices = new_indices;

  path->indices[0] = index;

}

/**

 * gtk_tree_path_get_depth:

 * @path: A #GtkTreePath.

 *

 * Returns the current depth of @path.

 *

 * Return value: The depth of @path

 **/

gint

gtk_tree_path_get_depth (GtkTreePath *path)

{

  g_return_val_if_fail (path != NULL, 0);

  return path->depth;

}

/**

 * gtk_tree_path_get_indices:

 * @path: A #GtkTreePath.

 *

 * Returns the current indices of @path.  This is an array of integers, each

 * representing a node in a tree.  This value should not be freed.

 *

 * Return value: The current indices, or %NULL.

 **/

gint *

gtk_tree_path_get_indices (GtkTreePath *path)

{

  g_return_val_if_fail (path != NULL, NULL);

  return path->indices;

}

/**

 * gtk_tree_path_get_indices_with_depth:

 * @path: A #GtkTreePath.

 * @depth: Number of elements returned in the integer array

 *

 * Returns the current indices of @path.

 * This is an array of integers, each representing a node in a tree.

 * It also returns the number of elements in the array.

 * The array should not be freed.

 *

 * Return value: (array length=depth) (transfer none): The current indices, or %NULL.

 *

 * Since: 2.22

 **/

gint *

gtk_tree_path_get_indices_with_depth (GtkTreePath *path, gint *depth)

{

  g_return_val_if_fail (path != NULL, NULL);

  if (depth)

    *depth = path->depth;

  return path->indices;

}

/**

 * gtk_tree_path_free:

 * @path: A #GtkTreePath.

 *

 * Frees @path.

 **/

void

gtk_tree_path_free (GtkTreePath *path)

{

  if (!path)

    return;

  g_free (path->indices);

  g_slice_free (GtkTreePath, path);

}

/**

 * gtk_tree_path_copy:

 * @path: A #GtkTreePath.

 *

 * Creates a new #GtkTreePath as a copy of @path.

 *

 * Return value: A new #GtkTreePath.

 **/

GtkTreePath *

gtk_tree_path_copy (const GtkTreePath *path)

{

  GtkTreePath *retval;

  g_return_val_if_fail (path != NULL, NULL);

  retval = g_slice_new (GtkTreePath);

  retval->depth = path->depth;

  retval->indices = g_new (gint, path->depth);

  memcpy (retval->indices, path->indices, path->depth * sizeof (gint));

  return retval;

}

GType

gtk_tree_path_get_type (void)

{

  static GType our_type = 0;

  if (our_type == 0)

    our_type = g_boxed_type_register_static (I_("GtkTreePath"),

					     (GBoxedCopyFunc) gtk_tree_path_copy,

					     (GBoxedFreeFunc) gtk_tree_path_free);

  return our_type;

}

/**

 * gtk_tree_path_compare:

 * @a: A #GtkTreePath.

 * @b: A #GtkTreePath to compare with.

 *

 * Compares two paths.  If @a appears before @b in a tree, then -1 is returned.

 * If @b appears before @a, then 1 is returned.  If the two nodes are equal,

 * then 0 is returned.

 *

 * Return value: The relative positions of @a and @b

 **/

gint

gtk_tree_path_compare (const GtkTreePath *a,

		       const GtkTreePath *b)

{

  gint p = 0, q = 0;

  g_return_val_if_fail (a != NULL, 0);

  g_return_val_if_fail (b != NULL, 0);

  g_return_val_if_fail (a->depth > 0, 0);

  g_return_val_if_fail (b->depth > 0, 0);

  do

    {

      if (a->indices[p] == b->indices[q])

	continue;

      return (a->indices[p] < b->indices[q]?-1:1);

    }

  while (++p < a->depth && ++q < b->depth);

  if (a->depth == b->depth)

    return 0;

  return (a->depth < b->depth?-1:1);

}

/**

 * gtk_tree_path_is_ancestor:

 * @path: a #GtkTreePath

 * @descendant: another #GtkTreePath

 *

 * Returns %TRUE if @descendant is a descendant of @path.

 *

 * Return value: %TRUE if @descendant is contained inside @path

 **/

gboolean

gtk_tree_path_is_ancestor (GtkTreePath *path,

                           GtkTreePath *descendant)

{

  gint i;

  g_return_val_if_fail (path != NULL, FALSE);

  g_return_val_if_fail (descendant != NULL, FALSE);

  /* can't be an ancestor if we're deeper */

  if (path->depth >= descendant->depth)

    return FALSE;

  i = 0;

  while (i < path->depth)

    {

      if (path->indices[i] != descendant->indices[i])

        return FALSE;

      ++i;

    }

  return TRUE;

}

/**

 * gtk_tree_path_is_descendant:

 * @path: a #GtkTreePath

 * @ancestor: another #GtkTreePath

 *

 * Returns %TRUE if @path is a descendant of @ancestor.

 *

 * Return value: %TRUE if @ancestor contains @path somewhere below it

 **/

gboolean

gtk_tree_path_is_descendant (GtkTreePath *path,

                             GtkTreePath *ancestor)

{

  gint i;

  g_return_val_if_fail (path != NULL, FALSE);

  g_return_val_if_fail (ancestor != NULL, FALSE);

  /* can't be a descendant if we're shallower in the tree */

  if (path->depth <= ancestor->depth)

    return FALSE;

  i = 0;

  while (i < ancestor->depth)

    {

      if (path->indices[i] != ancestor->indices[i])

        return FALSE;

      ++i;

    }

  return TRUE;

}

/**

 * gtk_tree_path_next:

 * @path: A #GtkTreePath.

 *

 * Moves the @path to point to the next node at the current depth.

 **/

void

gtk_tree_path_next (GtkTreePath *path)

{

  g_return_if_fail (path != NULL);

  g_return_if_fail (path->depth > 0);

  path->indices[path->depth - 1] ++;

}

/**

 * gtk_tree_path_prev:

 * @path: A #GtkTreePath.

 *

 * Moves the @path to point to the previous node at the current depth, 

 * if it exists.

 *

 * Return value: %TRUE if @path has a previous node, and the move was made.

 **/

gboolean

gtk_tree_path_prev (GtkTreePath *path)

{

  g_return_val_if_fail (path != NULL, FALSE);

  if (path->depth == 0)

    return FALSE;

  if (path->indices[path->depth - 1] == 0)

    return FALSE;

  path->indices[path->depth - 1] -= 1;

  return TRUE;

}

/**

 * gtk_tree_path_up:

 * @path: A #GtkTreePath.

 *

 * Moves the @path to point to its parent node, if it has a parent.

 *

 * Return value: %TRUE if @path has a parent, and the move was made.

 **/

gboolean

gtk_tree_path_up (GtkTreePath *path)

{

  g_return_val_if_fail (path != NULL, FALSE);

  if (path->depth == 0)

    return FALSE;

  path->depth--;

  return TRUE;

}

/**

 * gtk_tree_path_down:

 * @path: A #GtkTreePath.

 *

 * Moves @path to point to the first child of the current path.

 **/

void

gtk_tree_path_down (GtkTreePath *path)

{

  g_return_if_fail (path != NULL);

  gtk_tree_path_append_index (path, 0);

}

/**

 * gtk_tree_iter_copy:

 * @iter: A #GtkTreeIter.

 *

 * Creates a dynamically allocated tree iterator as a copy of @iter.  

 * This function is not intended for use in applications, because you 

 * can just copy the structs by value