Use undoview from deps/third_party/

third_party/undoview/undo_manager.c

Index: third_party/undoview/undo_manager.c
===================================================================
--- third_party/undoview/undo_manager.c	(revision 119883)
+++ third_party/undoview/undo_manager.c	(working copy)
@@ -1,1110 +0,0 @@
-/*
- * Copyright (C) 1998, 1999 Alex Roberts, Evan Lawrence
- * Copyright (C) 2000, 2001 Chema Celorio, Paolo Maggi
- * Copyright (C) 2002-2005 Paolo Maggi
- *
- * This library 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 2.1 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
- * Lesser General Public License for more details.
-
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#include <glib.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "undo_manager.h"
-
-#define DEFAULT_MAX_UNDO_LEVELS 25
-
-typedef struct _GtkSourceUndoAction GtkSourceUndoAction;
-typedef struct _GtkSourceUndoInsertAction GtkSourceUndoInsertAction;
-typedef struct _GtkSourceUndoDeleteAction GtkSourceUndoDeleteAction;
-
-typedef enum {
-  GTK_SOURCE_UNDO_ACTION_INSERT,
-  GTK_SOURCE_UNDO_ACTION_DELETE,
-} GtkSourceUndoActionType;
-
-/*
- * We use offsets instead of GtkTextIters because the last ones
- * require to much memory in this context without giving us any advantage.
- */
-
-struct _GtkSourceUndoInsertAction {
-  gint pos;
-  gchar *text;
-  gint length;
-  gint chars;
-};
-
-struct _GtkSourceUndoDeleteAction {
-  gint start;
-  gint end;
-  gchar *text;
-  gboolean forward;
-};
-
-struct _GtkSourceUndoAction {
-  GtkSourceUndoActionType action_type;
-
-  union {
-    GtkSourceUndoInsertAction insert;
-    GtkSourceUndoDeleteAction delete;
-  } action;
-
-  gint order_in_group;
-
-  /* It is TRUE whether the action can be merged with the following action. */
-  guint mergeable : 1;
-
-  /* It is TRUE whether the action is marked as "modified".
-   * An action is marked as "modified" if it changed the
-   * state of the buffer from "not modified" to "modified". Only the first
-   * action of a group can be marked as modified.
-   * There can be a single action marked as "modified" in the actions list.
-   */
-  guint modified : 1;
-};
-
-/* INVALID is a pointer to an invalid action */
-#define INVALID ((void *) "IA")
-
-struct _GtkSourceUndoManagerPrivate {
-  GtkTextBuffer *document;
-
-  GList* actions;
-  gint next_redo;
-
-  gint actions_in_current_group;
-
-  gint running_not_undoable_actions;
-
-  gint num_of_groups;
-
-  gint max_undo_levels;
-
-  guint can_undo : 1;
-  guint can_redo : 1;
-
-  /* It is TRUE whether, while undoing an action of the current group (with order_in_group > 1),
-   * the state of the buffer changed from "not modified" to "modified".
-   */
-  guint modified_undoing_group : 1;
-
-  /* Pointer to the action (in the action list) marked as "modified".
-   * It is NULL when no action is marked as "modified".
-   * It is INVALID when the action marked as "modified" has been removed
-   * from the action list (freeing the list or resizing it) */
-  GtkSourceUndoAction *modified_action;
-};
-
-enum {
-  CAN_UNDO,
-  CAN_REDO,
-  LAST_SIGNAL
-};
-
-#if !defined(NDEBUG)
-static void
-print_state(GtkSourceUndoManager* um)
-{
-  fprintf(stderr, "\n***\n");
-  GList* actions = um->priv->actions;
-
-  for (; actions; actions = g_list_next(actions)) {
-    GtkSourceUndoAction* act = actions->data;
-    fprintf(stderr, "* type = %s\n", act->action_type == GTK_SOURCE_UNDO_ACTION_DELETE ?
-        "delete" : "insert");
-
-    fprintf(stderr, "\ttext = %s\n", act->action_type == GTK_SOURCE_UNDO_ACTION_DELETE
-        ? act->action.delete.text : act->action.insert.text);
-    fprintf(stderr, "\torder = %d\n", act->order_in_group);
-  }
-
-  fprintf(stderr, "* next redo: %d\n", um->priv->next_redo);
-  fprintf(stderr, "* num of groups: %d\n", um->priv->num_of_groups);
-  fprintf(stderr, "* actions in group: %d\n", um->priv->actions_in_current_group);
-}
-#endif
-
-static void gtk_source_undo_manager_class_init(GtkSourceUndoManagerClass *klass);
-static void gtk_source_undo_manager_init(GtkSourceUndoManager *um);
-static void gtk_source_undo_manager_finalize(GObject *object);
-
-static void gtk_source_undo_manager_insert_text_handler(GtkTextBuffer *buffer,
-                  GtkTextIter *pos,
-                                         const gchar *text,
-                  gint length,
-                  GtkSourceUndoManager *um);
-static void gtk_source_undo_manager_delete_range_handler(GtkTextBuffer *buffer,
-                  GtkTextIter *start,
-                                          GtkTextIter *end,
-                  GtkSourceUndoManager *um);
-static void gtk_source_undo_manager_begin_user_action_handler(GtkTextBuffer *buffer,
-                 GtkSourceUndoManager *um);
-static void gtk_source_undo_manager_modified_changed_handler(GtkTextBuffer *buffer,
-                 GtkSourceUndoManager *um);
-
-static void gtk_source_undo_manager_free_action_list(GtkSourceUndoManager *um);
-
-static void gtk_source_undo_manager_add_action(GtkSourceUndoManager *um,
-                                                const GtkSourceUndoAction *undo_action);
-static void gtk_source_undo_manager_free_first_n_actions(GtkSourceUndoManager *um,
-                 gint n);
-static void gtk_source_undo_manager_check_list_size(GtkSourceUndoManager *um);
-
-static gboolean gtk_source_undo_manager_merge_action(GtkSourceUndoManager *um,
-                                               const GtkSourceUndoAction *undo_action);
-
-static GObjectClass *parent_class = NULL;
-static guint undo_manager_signals [LAST_SIGNAL] = { 0 };
-
-GType
-gtk_source_undo_manager_get_type(void) {
-  static GType undo_manager_type = 0;
-
-    if(undo_manager_type == 0)
-      {
-          static const GTypeInfo our_info =
-          {
-            sizeof(GtkSourceUndoManagerClass),
-            NULL, /* base_init */
-            NULL, /* base_finalize */
-            (GClassInitFunc) gtk_source_undo_manager_class_init,
-            NULL, /* class_finalize */
-            NULL, /* class_data */
-            sizeof(GtkSourceUndoManager),
-            0, /* n_preallocs */
-            (GInstanceInitFunc) gtk_source_undo_manager_init,
-            NULL /* value_table */
-          };
-
-          undo_manager_type = g_type_register_static(G_TYPE_OBJECT,
-              "GtkSourceUndoManager",
-              &our_info,
-              0);
-      }
-
-  return undo_manager_type;
-}
-
-static void
-gtk_source_undo_manager_class_init(GtkSourceUndoManagerClass *klass) {
-  GObjectClass *object_class = G_OBJECT_CLASS(klass);
-
-  parent_class = g_type_class_peek_parent(klass);
-
-  object_class->finalize = gtk_source_undo_manager_finalize;
-
-  klass->can_undo = NULL;
-  klass->can_redo = NULL;
-
-  undo_manager_signals[CAN_UNDO] =
-       g_signal_new("can_undo",
-            G_OBJECT_CLASS_TYPE(object_class),
-            G_SIGNAL_RUN_LAST,
-            G_STRUCT_OFFSET(GtkSourceUndoManagerClass, can_undo),
-            NULL, NULL,
-            g_cclosure_marshal_VOID__BOOLEAN,
-            G_TYPE_NONE,
-            1,
-            G_TYPE_BOOLEAN);
-
-  undo_manager_signals[CAN_REDO] =
-       g_signal_new("can_redo",
-            G_OBJECT_CLASS_TYPE(object_class),
-            G_SIGNAL_RUN_LAST,
-            G_STRUCT_OFFSET(GtkSourceUndoManagerClass, can_redo),
-            NULL, NULL,
-            g_cclosure_marshal_VOID__BOOLEAN,
-            G_TYPE_NONE,
-            1,
-            G_TYPE_BOOLEAN);
-}
-
-static void
-gtk_source_undo_manager_init(GtkSourceUndoManager *um) {
-  um->priv = g_new0(GtkSourceUndoManagerPrivate, 1);
-
-  um->priv->actions = NULL;
-  um->priv->next_redo = 0;
-
-  um->priv->can_undo = FALSE;
-  um->priv->can_redo = FALSE;
-
-  um->priv->running_not_undoable_actions = 0;
-
-  um->priv->num_of_groups = 0;
-
-  um->priv->max_undo_levels = DEFAULT_MAX_UNDO_LEVELS;
-
-  um->priv->modified_action = NULL;
-
-  um->priv->modified_undoing_group = FALSE;
-}
-
-static void
-gtk_source_undo_manager_finalize(GObject *object) {
-  GtkSourceUndoManager *um;
-
-  g_return_if_fail(object != NULL);
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(object));
-
-  um = GTK_SOURCE_UNDO_MANAGER(object);
-
-  g_return_if_fail(um->priv != NULL);
-
-  if(um->priv->actions != NULL)
-    gtk_source_undo_manager_free_action_list(um);
-
-  g_signal_handlers_disconnect_by_func(G_OBJECT(um->priv->document),
-        G_CALLBACK(gtk_source_undo_manager_delete_range_handler),
-        um);
-
-  g_signal_handlers_disconnect_by_func(G_OBJECT(um->priv->document),
-        G_CALLBACK(gtk_source_undo_manager_insert_text_handler),
-        um);
-
-  g_signal_handlers_disconnect_by_func(G_OBJECT(um->priv->document),
-        G_CALLBACK(gtk_source_undo_manager_begin_user_action_handler),
-        um);
-
-  g_signal_handlers_disconnect_by_func(G_OBJECT(um->priv->document),
-        G_CALLBACK(gtk_source_undo_manager_modified_changed_handler),
-        um);
-
-  g_free(um->priv);
-
-  G_OBJECT_CLASS(parent_class)->finalize(object);
-}
-
-GtkSourceUndoManager*
-gtk_source_undo_manager_new(GtkTextBuffer* buffer) {
-  GtkSourceUndoManager *um;
-
-  um = GTK_SOURCE_UNDO_MANAGER(g_object_new(GTK_SOURCE_TYPE_UNDO_MANAGER, NULL));
-
-  g_return_val_if_fail(um->priv != NULL, NULL);
-  um->priv->document = buffer;
-
-  g_signal_connect(G_OBJECT(buffer), "insert_text",
-        G_CALLBACK(gtk_source_undo_manager_insert_text_handler),
-        um);
-
-  g_signal_connect(G_OBJECT(buffer), "delete_range",
-        G_CALLBACK(gtk_source_undo_manager_delete_range_handler),
-        um);
-
-  g_signal_connect(G_OBJECT(buffer), "begin_user_action",
-        G_CALLBACK(gtk_source_undo_manager_begin_user_action_handler),
-        um);
-
-  g_signal_connect(G_OBJECT(buffer), "modified_changed",
-        G_CALLBACK(gtk_source_undo_manager_modified_changed_handler),
-        um);
-  return um;
-}
-
-void
-gtk_source_undo_manager_begin_not_undoable_action(GtkSourceUndoManager *um) {
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-
-  ++um->priv->running_not_undoable_actions;
-}
-
-static void
-gtk_source_undo_manager_end_not_undoable_action_internal(GtkSourceUndoManager *um) {
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-
-  g_return_if_fail(um->priv->running_not_undoable_actions > 0);
-
-  --um->priv->running_not_undoable_actions;
-}
-
-void
-gtk_source_undo_manager_end_not_undoable_action(GtkSourceUndoManager *um) {
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-
-  gtk_source_undo_manager_end_not_undoable_action_internal(um);
-
-  if(um->priv->running_not_undoable_actions == 0)
-  {
-    gtk_source_undo_manager_free_action_list(um);
-
-    um->priv->next_redo = -1;
-
-    if(um->priv->can_undo)
-    {
-      um->priv->can_undo = FALSE;
-      g_signal_emit(G_OBJECT(um),
-               undo_manager_signals [CAN_UNDO],
-               0,
-               FALSE);
-    }
-
-    if(um->priv->can_redo)
-    {
-      um->priv->can_redo = FALSE;
-      g_signal_emit(G_OBJECT(um),
-               undo_manager_signals [CAN_REDO],
-               0,
-               FALSE);
-    }
-  }
-}
-
-gboolean
-gtk_source_undo_manager_can_undo(const GtkSourceUndoManager *um) {
-  g_return_val_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um), FALSE);
-  g_return_val_if_fail(um->priv != NULL, FALSE);
-
-  return um->priv->can_undo;
-}
-
-gboolean
-gtk_source_undo_manager_can_redo(const GtkSourceUndoManager *um) {
-  g_return_val_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um), FALSE);
-  g_return_val_if_fail(um->priv != NULL, FALSE);
-
-  return um->priv->can_redo;
-}
-
-static void
-set_cursor(GtkTextBuffer *buffer, gint cursor) {
-  GtkTextIter iter;
-
-  /* Place the cursor at the requested position */
-  gtk_text_buffer_get_iter_at_offset(buffer, &iter, cursor);
-  gtk_text_buffer_place_cursor(buffer, &iter);
-}
-
-static void
-insert_text(GtkTextBuffer *buffer, gint pos, const gchar *text, gint len) {
-  GtkTextIter iter;
-
-  gtk_text_buffer_get_iter_at_offset(buffer, &iter, pos);
-  gtk_text_buffer_insert(buffer, &iter, text, len);
-}
-
-static void
-delete_text(GtkTextBuffer *buffer, gint start, gint end) {
-  GtkTextIter start_iter;
-  GtkTextIter end_iter;
-
-  gtk_text_buffer_get_iter_at_offset(buffer, &start_iter, start);
-
-  if(end < 0)
-    gtk_text_buffer_get_end_iter(buffer, &end_iter);
-  else
-    gtk_text_buffer_get_iter_at_offset(buffer, &end_iter, end);
-
-  gtk_text_buffer_delete(buffer, &start_iter, &end_iter);
-}
-
-static gchar*
-get_chars(GtkTextBuffer *buffer, gint start, gint end) {
-  GtkTextIter start_iter;
-  GtkTextIter end_iter;
-
-  gtk_text_buffer_get_iter_at_offset(buffer, &start_iter, start);
-
-  if(end < 0)
-    gtk_text_buffer_get_end_iter(buffer, &end_iter);
-  else
-    gtk_text_buffer_get_iter_at_offset(buffer, &end_iter, end);
-
-  return gtk_text_buffer_get_slice(buffer, &start_iter, &end_iter, TRUE);
-}
-
-void
-gtk_source_undo_manager_undo(GtkSourceUndoManager *um) {
-  GtkSourceUndoAction *undo_action;
-  gboolean modified = FALSE;
-
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-  g_return_if_fail(um->priv->can_undo);
-
-  um->priv->modified_undoing_group = FALSE;
-
-  gtk_source_undo_manager_begin_not_undoable_action(um);
-
-  do
-  {
-    undo_action = g_list_nth_data(um->priv->actions, um->priv->next_redo + 1);
-    g_return_if_fail(undo_action != NULL);
-
-    /* undo_action->modified can be TRUE only if undo_action->order_in_group <= 1 */
-    g_return_if_fail((undo_action->order_in_group <= 1) ||
-        ((undo_action->order_in_group > 1) && !undo_action->modified));
-
-    if(undo_action->order_in_group <= 1)
-    {
-      /* Set modified to TRUE only if the buffer did not change its state from
-       * "not modified" to "modified" undoing an action(with order_in_group > 1)
-       * in current group. */
-      modified =(undo_action->modified && !um->priv->modified_undoing_group);
-    }
-
-    switch(undo_action->action_type)
-    {
-      case GTK_SOURCE_UNDO_ACTION_DELETE:
-        insert_text(
-          um->priv->document,
-          undo_action->action.delete.start,
-          undo_action->action.delete.text,
-          strlen(undo_action->action.delete.text));
-
-        if(undo_action->action.delete.forward)
-          set_cursor(
-            um->priv->document,
-            undo_action->action.delete.start);
-        else
-          set_cursor(
-            um->priv->document,
-            undo_action->action.delete.end);
-
-        break;
-
-      case GTK_SOURCE_UNDO_ACTION_INSERT:
-        delete_text(
-          um->priv->document,
-          undo_action->action.insert.pos,
-          undo_action->action.insert.pos +
-            undo_action->action.insert.chars);
-
-        set_cursor(
-          um->priv->document,
-          undo_action->action.insert.pos);
-        break;
-
-      default:
-        /* Unknown action type. */
-        g_return_if_reached();
-    }
-
-    ++um->priv->next_redo;
-
-  } while(undo_action->order_in_group > 1);
-
-  if(modified)
-  {
-    --um->priv->next_redo;
-    gtk_text_buffer_set_modified(um->priv->document, FALSE);
-    ++um->priv->next_redo;
-  }
-
-  gtk_source_undo_manager_end_not_undoable_action_internal(um);
-
-  um->priv->modified_undoing_group = FALSE;
-
-  if(!um->priv->can_redo)
-  {
-    um->priv->can_redo = TRUE;
-    g_signal_emit(G_OBJECT(um),
-             undo_manager_signals [CAN_REDO],
-             0,
-             TRUE);
-  }
-
-  if(um->priv->next_redo >=(gint)(g_list_length(um->priv->actions) - 1))
-  {
-    um->priv->can_undo = FALSE;
-    g_signal_emit(G_OBJECT(um),
-             undo_manager_signals [CAN_UNDO],
-             0,
-             FALSE);
-  }
-}
-
-void
-gtk_source_undo_manager_redo(GtkSourceUndoManager *um) {
-  GtkSourceUndoAction *undo_action;
-  gboolean modified = FALSE;
-
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-  g_return_if_fail(um->priv->can_redo);
-
-  undo_action = g_list_nth_data(um->priv->actions, um->priv->next_redo);
-  g_return_if_fail(undo_action != NULL);
-
-  gtk_source_undo_manager_begin_not_undoable_action(um);
-
-  do
-  {
-    if(undo_action->modified)
-    {
-      g_return_if_fail(undo_action->order_in_group <= 1);
-      modified = TRUE;
-    }
-
-    --um->priv->next_redo;
-
-    switch(undo_action->action_type)
-    {
-      case GTK_SOURCE_UNDO_ACTION_DELETE:
-        delete_text(
-          um->priv->document,
-          undo_action->action.delete.start,
-          undo_action->action.delete.end);
-
-        set_cursor(
-          um->priv->document,
-          undo_action->action.delete.start);
-
-        break;
-
-      case GTK_SOURCE_UNDO_ACTION_INSERT:
-        set_cursor(
-          um->priv->document,
-          undo_action->action.insert.pos);
-
-        insert_text(
-          um->priv->document,
-          undo_action->action.insert.pos,
-          undo_action->action.insert.text,
-          undo_action->action.insert.length);
-
-        break;
-
-      default:
-        /* Unknown action type */
-        ++um->priv->next_redo;
-        g_return_if_reached();
-    }
-
-    if(um->priv->next_redo < 0)
-      undo_action = NULL;
-    else
-      undo_action = g_list_nth_data(um->priv->actions, um->priv->next_redo);
-
-  } while((undo_action != NULL) &&(undo_action->order_in_group > 1));
-
-  if(modified)
-  {
-    ++um->priv->next_redo;
-    gtk_text_buffer_set_modified(um->priv->document, FALSE);
-    --um->priv->next_redo;
-  }
-
-  gtk_source_undo_manager_end_not_undoable_action_internal(um);
-
-  if(um->priv->next_redo < 0)
-  {
-    um->priv->can_redo = FALSE;
-    g_signal_emit(G_OBJECT(um), undo_manager_signals [CAN_REDO], 0, FALSE);
-  }
-
-  if(!um->priv->can_undo)
-  {
-    um->priv->can_undo = TRUE;
-    g_signal_emit(G_OBJECT(um), undo_manager_signals [CAN_UNDO], 0, TRUE);
-  }
-}
-
-static void
-gtk_source_undo_action_free(GtkSourceUndoAction *action) {
-  if(action == NULL)
-    return;
-
-  if(action->action_type == GTK_SOURCE_UNDO_ACTION_INSERT)
-    g_free(action->action.insert.text);
-  else if(action->action_type == GTK_SOURCE_UNDO_ACTION_DELETE)
-    g_free(action->action.delete.text);
-  else
-    g_return_if_reached();
-
-  g_free(action);
-}
-
-static void
-gtk_source_undo_manager_free_action_list(GtkSourceUndoManager *um) {
-  GList *l;
-
-  l = um->priv->actions;
-
-  while(l != NULL)
-  {
-    GtkSourceUndoAction *action = l->data;
-
-    if(action->order_in_group == 1)
-      --um->priv->num_of_groups;
-    um->priv->actions_in_current_group = action->order_in_group - 1;
-
-    if(action->modified)
-      um->priv->modified_action = INVALID;
-
-    gtk_source_undo_action_free(action);
-
-    l = g_list_next(l);
-  }
-
-  g_list_free(um->priv->actions);
-  um->priv->actions = NULL;
-}
-
-static void
-gtk_source_undo_manager_insert_text_handler(GtkTextBuffer *buffer,
-    GtkTextIter *pos,
-    const gchar *text,
-    gint length,
-    GtkSourceUndoManager *um) {
-  GtkSourceUndoAction undo_action;
-
-  if(um->priv->running_not_undoable_actions > 0)
-    return;
-
-  undo_action.action_type = GTK_SOURCE_UNDO_ACTION_INSERT;
-
-  undo_action.action.insert.pos = gtk_text_iter_get_offset(pos);
-  undo_action.action.insert.text =(gchar*) text;
-  undo_action.action.insert.length = length;
-  undo_action.action.insert.chars = g_utf8_strlen(text, length);
-
-  if((undo_action.action.insert.chars > 1) ||(g_utf8_get_char(text) == '\n'))
-
-           undo_action.mergeable = FALSE;
-  else
-    undo_action.mergeable = TRUE;
-
-  undo_action.modified = FALSE;
-
-  gtk_source_undo_manager_add_action(um, &undo_action);
-}
-
-static void
-gtk_source_undo_manager_delete_range_handler(GtkTextBuffer *buffer,
-    GtkTextIter *start,
-    GtkTextIter *end,
-    GtkSourceUndoManager *um) {
-  GtkSourceUndoAction undo_action;
-  GtkTextIter insert_iter;
-
-  if(um->priv->running_not_undoable_actions > 0)
-    return;
-
-  undo_action.action_type = GTK_SOURCE_UNDO_ACTION_DELETE;
-
-  gtk_text_iter_order(start, end);
-
-  undo_action.action.delete.start = gtk_text_iter_get_offset(start);
-  undo_action.action.delete.end = gtk_text_iter_get_offset(end);
-
-  undo_action.action.delete.text = get_chars(
-            buffer,
-            undo_action.action.delete.start,
-            undo_action.action.delete.end);
-
-  /* figure out if the user used the Delete or the Backspace key */
-  gtk_text_buffer_get_iter_at_mark(buffer, &insert_iter,
-            gtk_text_buffer_get_insert(buffer));
-  if(gtk_text_iter_get_offset(&insert_iter) <= undo_action.action.delete.start)
-    undo_action.action.delete.forward = TRUE;
-  else
-    undo_action.action.delete.forward = FALSE;
-
-  if(((undo_action.action.delete.end - undo_action.action.delete.start) > 1) ||
-      (g_utf8_get_char(undo_action.action.delete.text ) == '\n'))
-           undo_action.mergeable = FALSE;
-  else
-    undo_action.mergeable = TRUE;
-
-  undo_action.modified = FALSE;
-
-  gtk_source_undo_manager_add_action(um, &undo_action);
-
-  g_free(undo_action.action.delete.text);
-
-}
-
-static void
-gtk_source_undo_manager_begin_user_action_handler(GtkTextBuffer *buffer, GtkSourceUndoManager *um) {
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-
-  if(um->priv->running_not_undoable_actions > 0)
-    return;
-
-  um->priv->actions_in_current_group = 0;
-}
-
-static void
-gtk_source_undo_manager_add_action(GtkSourceUndoManager *um,
-            const GtkSourceUndoAction *undo_action) {
-  GtkSourceUndoAction* action;
-
-  if(um->priv->next_redo >= 0)
-  {
-    gtk_source_undo_manager_free_first_n_actions(um, um->priv->next_redo + 1);
-  }
-
-  um->priv->next_redo = -1;
-
-  if(!gtk_source_undo_manager_merge_action(um, undo_action))
-  {
-    action = g_new(GtkSourceUndoAction, 1);
-    *action = *undo_action;
-
-    if(action->action_type == GTK_SOURCE_UNDO_ACTION_INSERT)
-      action->action.insert.text = g_strndup(undo_action->action.insert.text, undo_action->action.insert.length);
-    else if(action->action_type == GTK_SOURCE_UNDO_ACTION_DELETE)
-      action->action.delete.text = g_strdup(undo_action->action.delete.text);
-    else
-    {
-      g_free(action);
-      g_return_if_reached();
-    }
-
-    ++um->priv->actions_in_current_group;
-    action->order_in_group = um->priv->actions_in_current_group;
-
-    if(action->order_in_group == 1)
-      ++um->priv->num_of_groups;
-
-    um->priv->actions = g_list_prepend(um->priv->actions, action);
-  }
-
-  gtk_source_undo_manager_check_list_size(um);
-
-  if(!um->priv->can_undo)
-  {
-    um->priv->can_undo = TRUE;
-    g_signal_emit(G_OBJECT(um), undo_manager_signals [CAN_UNDO], 0, TRUE);
-  }
-
-  if(um->priv->can_redo)
-  {
-    um->priv->can_redo = FALSE;
-    g_signal_emit(G_OBJECT(um), undo_manager_signals [CAN_REDO], 0, FALSE);
-  }
-}
-
-static void
-gtk_source_undo_manager_free_first_n_actions(GtkSourceUndoManager *um,
-                gint n) {
-  gint i;
-
-  if(um->priv->actions == NULL)
-    return;
-
-  for(i = 0; i < n; i++)
-  {
-    GtkSourceUndoAction *action = g_list_first(um->priv->actions)->data;
-
-    if(action->order_in_group == 1)
-      --um->priv->num_of_groups;
-    um->priv->actions_in_current_group = action->order_in_group - 1;
-
-    if(action->modified)
-      um->priv->modified_action = INVALID;
-
-    gtk_source_undo_action_free(action);
-
-    um->priv->actions = g_list_delete_link(um->priv->actions,
-              um->priv->actions);
-
-    if(um->priv->actions == NULL)
-      return;
-  }
-}
-
-static void
-gtk_source_undo_manager_check_list_size(GtkSourceUndoManager *um) {
-  gint undo_levels;
-
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-
-  undo_levels = gtk_source_undo_manager_get_max_undo_levels(um);
-
-  if(undo_levels < 1)
-    return;
-
-  if(um->priv->num_of_groups > undo_levels)
-  {
-    GtkSourceUndoAction *undo_action;
-    GList *last;
-
-    last = g_list_last(um->priv->actions);
-    undo_action =(GtkSourceUndoAction*) last->data;
-
-    do
-    {
-      GList *tmp;
-
-      if(undo_action->order_in_group == 1)
-        --um->priv->num_of_groups;
-      um->priv->actions_in_current_group = undo_action->order_in_group - 1;
-
-      if(undo_action->modified)
-        um->priv->modified_action = INVALID;
-
-      gtk_source_undo_action_free(undo_action);
-
-      tmp = g_list_previous(last);
-      um->priv->actions = g_list_delete_link(um->priv->actions, last);
-      last = tmp;
-      g_return_if_fail(last != NULL);
-
-      undo_action =(GtkSourceUndoAction*) last->data;
-
-    } while((undo_action->order_in_group > 1) ||
-      (um->priv->num_of_groups > undo_levels));
-  }
-}
-
-/**
- * gtk_source_undo_manager_merge_action:
- * @um: a #GtkSourceUndoManager.
- * @undo_action: a #GtkSourceUndoAction.
- *
- * This function tries to merge the undo action at the top of
- * the stack with a new undo action. So when we undo for example
- * typing, we can undo the whole word and not each letter by itself.
- *
- * Return Value: %TRUE is merge was successful, %FALSE otherwise.
- **/
-static gboolean
-gtk_source_undo_manager_merge_action(GtkSourceUndoManager *um,
-              const GtkSourceUndoAction *undo_action) {
-  GtkSourceUndoAction *last_action;
-
-  g_return_val_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um), FALSE);
-  g_return_val_if_fail(um->priv != NULL, FALSE);
-
-  if(um->priv->actions == NULL)
-    return FALSE;
-
-  last_action =(GtkSourceUndoAction*) g_list_nth_data(um->priv->actions, 0);
-
-  if(!last_action->mergeable)
-    return FALSE;
-
-  if((!undo_action->mergeable) ||
-     (undo_action->action_type != last_action->action_type))
-  {
-    last_action->mergeable = FALSE;
-    return FALSE;
-  }
-
-  if(undo_action->action_type == GTK_SOURCE_UNDO_ACTION_DELETE)
-  {
-    if((last_action->action.delete.forward != undo_action->action.delete.forward) ||
-       ((last_action->action.delete.start != undo_action->action.delete.start) &&
-        (last_action->action.delete.start != undo_action->action.delete.end)))
-    {
-      last_action->mergeable = FALSE;
-      return FALSE;
-    }
-
-    if(last_action->action.delete.start == undo_action->action.delete.start)
-    {
-      gchar *str;
-
-#define L (last_action->action.delete.end - last_action->action.delete.start - 1)
-#define g_utf8_get_char_at(p,i) g_utf8_get_char(g_utf8_offset_to_pointer((p),(i)))
-
-      /* Deleted with the delete key */
-      if((g_utf8_get_char(undo_action->action.delete.text) != ' ') &&
-         (g_utf8_get_char(undo_action->action.delete.text) != '\t') &&
-                           ((g_utf8_get_char_at(last_action->action.delete.text, L) == ' ') ||
-          (g_utf8_get_char_at(last_action->action.delete.text, L) == '\t')))
-      {
-        last_action->mergeable = FALSE;
-        return FALSE;
-      }
-
-      str = g_strdup_printf("%s%s", last_action->action.delete.text,
-        undo_action->action.delete.text);
-
-      g_free(last_action->action.delete.text);
-      last_action->action.delete.end +=(undo_action->action.delete.end -
-                 undo_action->action.delete.start);
-      last_action->action.delete.text = str;
-    }
-    else
-    {
-      gchar *str;
-
-      /* Deleted with the backspace key */
-      if((g_utf8_get_char(undo_action->action.delete.text) != ' ') &&
-         (g_utf8_get_char(undo_action->action.delete.text) != '\t') &&
-                           ((g_utf8_get_char(last_action->action.delete.text) == ' ') ||
-          (g_utf8_get_char(last_action->action.delete.text) == '\t')))
-      {
-        last_action->mergeable = FALSE;
-        return FALSE;
-      }
-
-      str = g_strdup_printf("%s%s", undo_action->action.delete.text,
-        last_action->action.delete.text);
-
-      g_free(last_action->action.delete.text);
-      last_action->action.delete.start = undo_action->action.delete.start;
-      last_action->action.delete.text = str;
-    }
-  }
-  else if(undo_action->action_type == GTK_SOURCE_UNDO_ACTION_INSERT)
-  {
-    gchar* str;
-
-#define I (last_action->action.insert.chars - 1)
-
-    if((undo_action->action.insert.pos !=
-          (last_action->action.insert.pos + last_action->action.insert.chars)) ||
-       ((g_utf8_get_char(undo_action->action.insert.text) != ' ') &&
-         (g_utf8_get_char(undo_action->action.insert.text) != '\t') &&
-        ((g_utf8_get_char_at(last_action->action.insert.text, I) == ' ') ||
-         (g_utf8_get_char_at(last_action->action.insert.text, I) == '\t')))
-       )
-    {
-      last_action->mergeable = FALSE;
-      return FALSE;
-    }
-
-    str = g_strdup_printf("%s%s", last_action->action.insert.text,
-        undo_action->action.insert.text);
-
-    g_free(last_action->action.insert.text);
-    last_action->action.insert.length += undo_action->action.insert.length;
-    last_action->action.insert.text = str;
-    last_action->action.insert.chars += undo_action->action.insert.chars;
-
-  }
-  else
-    /* Unknown action inside undo merge encountered */
-    g_return_val_if_reached(TRUE);
-
-  return TRUE;
-}
-
-gint
-gtk_source_undo_manager_get_max_undo_levels(GtkSourceUndoManager *um) {
-  g_return_val_if_fail(um != NULL, 0);
-  g_return_val_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um), 0);
-
-  return um->priv->max_undo_levels;
-}
-
-void
-gtk_source_undo_manager_set_max_undo_levels(GtkSourceUndoManager *um,
-                 gint max_undo_levels) {
-  gint old_levels;
-
-  g_return_if_fail(um != NULL);
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-
-  old_levels = um->priv->max_undo_levels;
-  um->priv->max_undo_levels = max_undo_levels;
-
-  if(max_undo_levels < 1)
-    return;
-
-  if(old_levels > max_undo_levels)
-  {
-    /* strip redo actions first */
-    while(um->priv->next_redo >= 0 &&(um->priv->num_of_groups > max_undo_levels))
-    {
-      gtk_source_undo_manager_free_first_n_actions(um, 1);
-      um->priv->next_redo--;
-    }
-
-    /* now remove undo actions if necessary */
-    gtk_source_undo_manager_check_list_size(um);
-
-    /* emit "can_undo" and/or "can_redo" if appropiate */
-    if(um->priv->next_redo < 0 && um->priv->can_redo)
-    {
-      um->priv->can_redo = FALSE;
-      g_signal_emit(G_OBJECT(um), undo_manager_signals [CAN_REDO], 0, FALSE);
-    }
-
-    if(um->priv->can_undo &&
-        um->priv->next_redo >=(gint)(g_list_length(um->priv->actions) - 1))
-    {
-      um->priv->can_undo = FALSE;
-      g_signal_emit(G_OBJECT(um), undo_manager_signals [CAN_UNDO], 0, FALSE);
-    }
-  }
-}
-
-static void
-gtk_source_undo_manager_modified_changed_handler(GtkTextBuffer *buffer,
-                                                GtkSourceUndoManager *um) {
-  GtkSourceUndoAction *action;
-  GList *list;
-
-  g_return_if_fail(GTK_SOURCE_IS_UNDO_MANAGER(um));
-  g_return_if_fail(um->priv != NULL);
-
-  if(um->priv->actions == NULL)
-    return;
-
-  list = g_list_nth(um->priv->actions, um->priv->next_redo + 1);
-
-  if(list != NULL)
-    action =(GtkSourceUndoAction*) list->data;
-  else
-    action = NULL;
-
-  if(gtk_text_buffer_get_modified(buffer) == FALSE)
-  {
-    if(action != NULL)
-      action->mergeable = FALSE;
-
-    if(um->priv->modified_action != NULL)
-    {
-      if(um->priv->modified_action != INVALID)
-        um->priv->modified_action->modified = FALSE;
-
-      um->priv->modified_action = NULL;
-    }
-
-    return;
-  }
-
-  if(action == NULL)
-  {
-    g_return_if_fail(um->priv->running_not_undoable_actions > 0);
-
-    return;
-  }
-
-  /* gtk_text_buffer_get_modified(buffer) == TRUE */
-
-  g_return_if_fail(um->priv->modified_action == NULL);
-
-  if(action->order_in_group > 1)
-    um->priv->modified_undoing_group = TRUE;
-
-  while(action->order_in_group > 1)
-  {
-    list = g_list_next(list);
-    g_return_if_fail(list != NULL);
-
-    action =(GtkSourceUndoAction*) list->data;
-    g_return_if_fail(action != NULL);
-  }
-
-  action->modified = TRUE;
-  um->priv->modified_action = action;
-}
-