src/undo.c

   1 /*
   2  * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2001 Hiroyuki Yamamoto
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 /* code ported from gedit */
  21 /* This is for my patient girlfirend Regina */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include "config.h"
  25 #endif
  26
  27 #include <glib.h>
  28
  29 #include <string.h> /* for strlen */
  30 #include <stdlib.h> /* for mbstowcs */
  31
  32 #include "undo.h"
  33 #include "utils.h"
  34 #include "prefs_common.h"
  35 #include "gtkstext.h"
  36
  37 typedef struct _UndoInfo UndoInfo;
  38
  39 struct _UndoInfo
  40 {
  41         UndoAction action;
  42         gchar *text;
  43         gint start_pos;
  44         gint end_pos;
  45         gfloat window_position;
  46         gint mergeable;
  47 };
  48
  49 static void undo_free_list      (GList         **list_pointer);
  50 static void undo_check_size     (UndoMain       *undostruct);
  51 static gint undo_merge          (GList          *list,
  52                                  guint           start_pos,
  53                                  guint           end_pos,
  54                                  gint            action,
  55                                  const guchar   *text);
  56 static void undo_add            (const gchar    *text,
  57                                  gint            start_pos,
  58                                  gint            end_pos,
  59                                  UndoAction      action,
  60                                  UndoMain       *undostruct);
  61 static gint undo_get_selection  (GtkEditable    *text,
  62                                  guint          *start,
  63                                  guint          *end);
  64 static void undo_insert_text_cb (GtkEditable    *editable,
  65                                  gchar          *new_text,
  66                                  gint            new_text_length,
  67                                  gint           *position,
  68                                  UndoMain       *undostruct);
  69 static void undo_delete_text_cb (GtkEditable    *editable,
  70                                  gint            start_pos,
  71                                  gint            end_pos,
  72                                  UndoMain       *undostruct);
  73
  74 static void undo_paste_clipboard_cb     (GtkEditable    *editable,
  75                                          UndoMain       *undostruct);
  76
  77 void undo_undo                  (UndoMain       *undostruct);
  78 void undo_redo                  (UndoMain       *undostruct);
  79
  80
  81 UndoMain *undo_init(GtkWidget *text)
  82 {
  83         UndoMain *undostruct;
  84
  85         g_return_val_if_fail(text != NULL, NULL);
  86
  87         undostruct = g_new(UndoMain, 1);
  88         undostruct->text = text;
  89         undostruct->undo = NULL;
  90         undostruct->redo = NULL;
  91         undostruct->paste = 0;
  92         undostruct->undo_state = FALSE;
  93         undostruct->redo_state = FALSE;
  94
  95         gtk_signal_connect(GTK_OBJECT(text), "insert-text",
  96                            GTK_SIGNAL_FUNC(undo_insert_text_cb), undostruct);
  97         gtk_signal_connect(GTK_OBJECT(text), "delete-text",
  98                            GTK_SIGNAL_FUNC(undo_delete_text_cb), undostruct);
  99         gtk_signal_connect(GTK_OBJECT(text), "paste-clipboard",
 100                            GTK_SIGNAL_FUNC(undo_paste_clipboard_cb), undostruct);
 101
 102         return undostruct;
 103 }
 104
 105 void undo_destroy (UndoMain *undostruct)
 106 {
 107         undo_free_list(&undostruct->undo);
 108         undo_free_list(&undostruct->redo);
 109         g_free(undostruct);
 110 }
 111
 112 static UndoInfo *undo_object_new(gchar *text, gint start_pos, gint end_pos,
 113                                  UndoAction action, gfloat window_position)
 114 {
 115         UndoInfo *undoinfo;
 116         undoinfo = g_new (UndoInfo, 1);
 117         undoinfo->text      = text;
 118         undoinfo->start_pos = start_pos;
 119         undoinfo->end_pos   = end_pos;
 120         undoinfo->action    = action;
 121         undoinfo->window_position = window_position;
 122         return undoinfo;
 123 }
 124
 125 static void undo_object_free(UndoInfo *undo)
 126 {
 127         g_free (undo->text);
 128         g_free (undo);
 129 }
 130
 131 /**
 132  * undo_free_list:
 133  * @list_pointer: list to be freed
 134  *
 135  * frees and undo structure list
 136  **/
 137 static void undo_free_list(GList **list_pointer)
 138 {
 139         UndoInfo *undo;
 140         GList *cur, *list = *list_pointer;
 141
 142         if (list == NULL) return;
 143
 144         for (cur = list; cur != NULL; cur = cur->next) {
 145                 undo = (UndoInfo *)cur->data;
 146                 undo_object_free(undo);
 147         }
 148
 149         g_list_free(list);
 150         *list_pointer = NULL;
 151 }
 152
 153 void undo_set_change_state_func(UndoMain *undostruct, UndoChangeStateFunc func,
 154                                 gpointer data)
 155 {
 156         g_return_if_fail(undostruct != NULL);
 157
 158         undostruct->change_state_func = func;
 159         undostruct->change_state_data = data;
 160 }
 161
 162 /**
 163  * undo_check_size:
 164  * @compose: document to check
 165  *
 166  * Checks that the size of compose->undo does not excede settings->undo_levels and
 167  * frees any undo level above sett->undo_level.
 168  *
 169  **/
 170 static void undo_check_size(UndoMain *undostruct)
 171 {
 172         UndoInfo *last_undo;
 173         guint length;
 174
 175         if (prefs_common.undolevels < 1) return;
 176
 177         /* No need to check for the redo list size since the undo
 178            list gets freed on any call to compose_undo_add */
 179         length = g_list_length(undostruct->undo);
 180         if (length >= prefs_common.undolevels && prefs_common.undolevels > 0) {
 181                 last_undo = (UndoInfo *)g_list_last(undostruct->undo)->data;
 182                 undostruct->undo = g_list_remove(undostruct->undo, last_undo);
 183                 undo_object_free(last_undo);
 184         }
 185 }
 186
 187 /**
 188  * undo_merge:
 189  * @last_undo:
 190  * @start_pos:
 191  * @end_pos:
 192  * @action:
 193  *
 194  * This function tries to merge the undo object at the top of
 195  * the stack with a new set of data. So when we undo for example
 196  * typing, we can undo the whole word and not each letter by itself
 197  *
 198  * Return Value: TRUE is merge was sucessful, FALSE otherwise
 199  **/
 200 static gint undo_merge(GList *list, guint start_pos, guint end_pos,
 201                        gint action, const guchar *text)
 202 {
 203         guchar *temp_string;
 204         UndoInfo *last_undo;
 205
 206         /* This are the cases in which we will NOT merge :
 207            1. if (last_undo->mergeable == FALSE)
 208            [mergeable = FALSE when the size of the undo data was not 1.
 209            or if the data was size = 1 but = '\n' or if the undo object
 210            has been "undone" already ]
 211            2. The size of text is not 1
 212            3. If the new merging data is a '\n'
 213            4. If the last char of the undo_last data is a space/tab
 214            and the new char is not a space/tab ( so that we undo
 215            words and not chars )
 216            5. If the type (action) of undo is different from the last one
 217            Chema */
 218
 219         if (list == NULL) return FALSE;
 220
 221         last_undo = list->data;
 222
 223         if (!last_undo->mergeable) return FALSE;
 224
 225         if (end_pos - start_pos != 1 ||
 226             text[0] == '\n' ||
 227             action != last_undo->action ||
 228             action == UNDO_ACTION_REPLACE_INSERT ||
 229             action == UNDO_ACTION_REPLACE_DELETE) {
 230                 last_undo->mergeable = FALSE;
 231                 return FALSE;
 232         }
 233
 234         if (action == UNDO_ACTION_DELETE) {
 235                 gboolean checkit = TRUE;
 236
 237                 if (last_undo->start_pos != end_pos &&
 238                     last_undo->start_pos != start_pos) {
 239                         last_undo->mergeable = FALSE;
 240                         return FALSE;
 241                 } else if (last_undo->start_pos == start_pos) {
 242                         /* Deleted with the delete key */
 243                         if (text[0] != ' ' && text[0] != '\t' &&
 244                             (last_undo->text[last_undo->end_pos - last_undo->start_pos - 1] == ' ' ||
 245                              last_undo->text[last_undo->end_pos - last_undo->start_pos - 1] == '\t'))
 246                                 checkit = FALSE;
 247
 248                         temp_string = g_strdup_printf("%s%s", last_undo->text, text);
 249                         last_undo->end_pos++;
 250                         g_free(last_undo->text);
 251                         last_undo->text = temp_string;
 252                 } else {
 253                         /* Deleted with the backspace key */
 254                         if (text[0] != ' ' && text[0] != '\t' &&
 255                             (last_undo->text[0] == ' ' ||
 256                              last_undo->text[0] == '\t'))
 257                                 checkit = FALSE;
 258
 259                         temp_string = g_strdup_printf("%s%s", text, last_undo->text);
 260                         last_undo->start_pos = start_pos;
 261                         g_free(last_undo->text);
 262                         last_undo->text = temp_string;
 263                 }
 264
 265                 if (!checkit) {
 266                         last_undo->mergeable = FALSE;
 267                         return FALSE;
 268                 }
 269         } else if (action == UNDO_ACTION_INSERT) {
 270                 if (last_undo->end_pos != start_pos) {
 271                         last_undo->mergeable = FALSE;
 272                         return FALSE;
 273                 } else {
 274                         temp_string = g_strdup_printf("%s%s", last_undo->text, text);
 275                         g_free(last_undo->text);
 276                         last_undo->end_pos = end_pos;
 277                         last_undo->text = temp_string;
 278                 }
 279         } else
 280                 debug_print("Unknown action [%i] inside undo merge encountered", action);
 281
 282         return TRUE;
 283 }
 284
 285 /**
 286  * compose_undo_add:
 287  * @text:
 288  * @start_pos:
 289  * @end_pos:
 290  * @action: either UNDO_ACTION_INSERT or UNDO_ACTION_DELETE
 291  * @compose:
 292  * @view: The view so that we save the scroll bar position.
 293  *
 294  * Adds text to the undo stack. It also performs test to limit the number
 295  * of undo levels and deltes the redo list
 296  **/
 297
 298 static void undo_add(const gchar *text,
 299                      gint start_pos, gint end_pos,
 300                      UndoAction action, UndoMain *undostruct)
 301 {
 302         UndoInfo *undoinfo;
 303
 304         g_return_if_fail(text != NULL);
 305         g_return_if_fail(end_pos >= start_pos);
 306
 307         undo_free_list(&undostruct->redo);
 308
 309         /* Set the redo sensitivity */
 310         undostruct->change_state_func(undostruct,
 311                                       UNDO_STATE_UNCHANGED, UNDO_STATE_FALSE,
 312                                       undostruct->change_state_data);
 313
 314         if (undostruct->paste != 0) {
 315                 if (action == UNDO_ACTION_INSERT)
 316                         action = UNDO_ACTION_REPLACE_INSERT;
 317                 else
 318                         action = UNDO_ACTION_REPLACE_DELETE;
 319                 undostruct->paste = undostruct->paste + 1;
 320                 if (undostruct->paste == 3)
 321                         undostruct->paste = 0;
 322         }
 323
 324         if (undo_merge(undostruct->undo, start_pos, end_pos, action, text))
 325                 return;
 326
 327         undo_check_size(undostruct);
 328
 329         undoinfo = undo_object_new(g_strdup(text), start_pos, end_pos, action,
 330                                    GTK_ADJUSTMENT(GTK_STEXT(undostruct->text)->vadj)->value);
 331
 332         if (end_pos - start_pos != 1 || text[0] == '\n')
 333                 undoinfo->mergeable = FALSE;
 334         else
 335                 undoinfo->mergeable = TRUE;
 336
 337         undostruct->undo = g_list_prepend(undostruct->undo, undoinfo);
 338
 339         undostruct->change_state_func(undostruct,
 340                                       UNDO_STATE_TRUE, UNDO_STATE_UNCHANGED,
 341                                       undostruct->change_state_data);
 342 }
 343
 344 /**
 345  * undo_undo:
 346  * @w: not used
 347  * @data: not used
 348  *
 349  * Executes an undo request on the current document
 350  **/
 351 void undo_undo(UndoMain *undostruct)
 352 {
 353         UndoInfo *undoinfo;
 354         guint start_pos, end_pos;
 355
 356         g_return_if_fail(undostruct != NULL);
 357
 358         if (undostruct->undo == NULL) return;
 359
 360         /* The undo data we need is always at the top op the
 361            stack. So, therefore, the first one */
 362         undoinfo = (UndoInfo *)undostruct->undo->data;
 363         g_return_if_fail(undoinfo != NULL);
 364         undoinfo->mergeable = FALSE;
 365         undostruct->redo = g_list_prepend(undostruct->redo, undoinfo);
 366         undostruct->undo = g_list_remove(undostruct->undo, undoinfo);
 367
 368         /* Check if there is a selection active */
 369         start_pos = GTK_EDITABLE(undostruct->text)->selection_start_pos;
 370         end_pos   = GTK_EDITABLE(undostruct->text)->selection_end_pos;
 371         if ((start_pos > 0 || end_pos > 0) && (start_pos != end_pos))
 372                 gtk_editable_select_region(GTK_EDITABLE(undostruct->text),
 373                                            0, 0);
 374
 375         /* Move the view (scrollbars) to the correct position */
 376         gtk_adjustment_set_value
 377                 (GTK_ADJUSTMENT(GTK_STEXT(undostruct->text)->vadj),
 378                  undoinfo->window_position);
 379
 380         switch (undoinfo->action) {
 381         case UNDO_ACTION_DELETE:
 382                 gtk_stext_set_point(GTK_STEXT(undostruct->text), undoinfo->start_pos);
 383                 gtk_stext_insert(GTK_STEXT(undostruct->text), NULL, NULL, NULL, undoinfo->text, -1);
 384                 break;
 385         case UNDO_ACTION_INSERT:
 386                 gtk_stext_set_point(GTK_STEXT(undostruct->text), undoinfo->end_pos);
 387                 gtk_stext_backward_delete(GTK_STEXT(undostruct->text), undoinfo->end_pos-undoinfo->start_pos);
 388                 break;
 389         case UNDO_ACTION_REPLACE_INSERT:
 390                 gtk_stext_set_point(GTK_STEXT(undostruct->text), undoinfo->end_pos);
 391                 gtk_stext_backward_delete(GTK_STEXT(undostruct->text), undoinfo->end_pos-undoinfo->start_pos);
 392                 /* "pull" another data structure from the list */
 393                 undoinfo = (UndoInfo *)undostruct->undo->data;
 394                 g_return_if_fail(undoinfo != NULL);
 395                 undostruct->redo = g_list_prepend(undostruct->redo, undoinfo);
 396                 undostruct->undo = g_list_remove(undostruct->undo, undoinfo);
 397                 g_return_if_fail(undoinfo->action == UNDO_ACTION_REPLACE_DELETE);
 398                 gtk_stext_set_point(GTK_STEXT(undostruct->text), undoinfo->start_pos);
 399                 gtk_stext_insert(GTK_STEXT(undostruct->text), NULL, NULL, NULL, undoinfo->text, -1);
 400                 break;
 401         case UNDO_ACTION_REPLACE_DELETE:
 402                 g_warning("This should not happen. UNDO_REPLACE_DELETE");
 403                 break;
 404         default:
 405                 g_assert_not_reached();
 406                 break;
 407         }
 408
 409         undostruct->change_state_func(undostruct,
 410                                       UNDO_STATE_UNCHANGED, UNDO_STATE_TRUE,
 411                                       undostruct->change_state_data);
 412
 413         if (undostruct->undo == NULL)
 414                 undostruct->change_state_func(undostruct,
 415                                               UNDO_STATE_FALSE,
 416                                               UNDO_STATE_UNCHANGED,
 417                                               undostruct->change_state_data);
 418 }
 419
 420 /**
 421  * undo_redo:
 422  * @w: not used
 423  * @data: not used
 424  *
 425  * executes a redo request on the current document
 426  **/
 427 void undo_redo(UndoMain *undostruct)
 428 {
 429         UndoInfo *redoinfo;
 430         guint start_pos, end_pos;
 431
 432         g_return_if_fail(undostruct != NULL);
 433
 434         if (undostruct->redo == NULL) return;
 435
 436         redoinfo = (UndoInfo *)undostruct->redo->data;
 437         g_return_if_fail (redoinfo != NULL);
 438         undostruct->undo = g_list_prepend(undostruct->undo, redoinfo);
 439         undostruct->redo = g_list_remove(undostruct->redo, redoinfo);
 440
 441         /* Check if there is a selection active */
 442         start_pos = GTK_EDITABLE(undostruct->text)->selection_start_pos;
 443         end_pos   = GTK_EDITABLE(undostruct->text)->selection_end_pos;
 444         if ((start_pos > 0 || end_pos > 0) && (start_pos != end_pos))
 445                 gtk_editable_select_region(GTK_EDITABLE(undostruct->text), 0, 0);
 446
 447         /* Move the view to the right position. */
 448         gtk_adjustment_set_value(GTK_ADJUSTMENT(GTK_STEXT(undostruct->text)->vadj),
 449                                  redoinfo->window_position);
 450
 451         switch (redoinfo->action) {
 452         case UNDO_ACTION_INSERT:
 453                 gtk_stext_set_point(GTK_STEXT(undostruct->text),
 454                                    redoinfo->start_pos);
 455                 gtk_stext_insert(GTK_STEXT(undostruct->text), NULL, NULL,
 456                                 NULL, redoinfo->text, -1);
 457                 break;
 458         case UNDO_ACTION_DELETE:
 459                 gtk_stext_set_point(GTK_STEXT(undostruct->text),
 460                                    redoinfo->end_pos);
 461                 gtk_stext_backward_delete
 462                         (GTK_STEXT(undostruct->text),
 463                          redoinfo->end_pos - redoinfo->start_pos);
 464                 break;
 465         case UNDO_ACTION_REPLACE_DELETE:
 466                 gtk_stext_set_point(GTK_STEXT(undostruct->text),
 467                                    redoinfo->end_pos);
 468                 gtk_stext_backward_delete
 469                         (GTK_STEXT(undostruct->text),
 470                          redoinfo->end_pos - redoinfo->start_pos);
 471                 /* "pull" another data structure from the list */
 472                 redoinfo = (UndoInfo *)undostruct->redo->data;
 473                 g_return_if_fail(redoinfo != NULL);
 474                 undostruct->undo = g_list_prepend(undostruct->undo, redoinfo);
 475                 undostruct->redo = g_list_remove(undostruct->redo, redoinfo);
 476                 g_return_if_fail(redoinfo->action == UNDO_ACTION_REPLACE_INSERT);
 477                 gtk_stext_set_point(GTK_STEXT(undostruct->text),
 478                                    redoinfo->start_pos);
 479                 gtk_stext_insert(GTK_STEXT(undostruct->text), NULL, NULL,
 480                                 NULL, redoinfo->text, -1);
 481                 break;
 482         case UNDO_ACTION_REPLACE_INSERT:
 483                 g_warning("This should not happen. Redo: UNDO_REPLACE_INSERT");
 484                 break;
 485         default:
 486                 g_assert_not_reached();
 487                 break;
 488         }
 489
 490         undostruct->change_state_func(undostruct,
 491                                       UNDO_STATE_TRUE, UNDO_STATE_UNCHANGED,
 492                                       undostruct->change_state_data);
 493
 494         if (undostruct->redo == NULL)
 495                 undostruct->change_state_func(undostruct,
 496                                               UNDO_STATE_UNCHANGED,
 497                                               UNDO_STATE_FALSE,
 498                                               undostruct->change_state_data);
 499 }
 500
 501 void undo_insert_text_cb(GtkEditable *editable, gchar *new_text,
 502                          gint new_text_length, gint *position,
 503                          UndoMain *undostruct)
 504 {
 505         gchar *text_to_insert;
 506         size_t wlen;
 507
 508         if (prefs_common.undolevels <= 0) return;
 509
 510         Xstrndup_a(text_to_insert, new_text, new_text_length, return);
 511         if (MB_CUR_MAX > 1) {
 512                 wchar_t *wstr;
 513
 514                 wstr = g_new(wchar_t, new_text_length + 1);
 515                 wlen = mbstowcs(wstr, text_to_insert, new_text_length + 1);
 516                 g_free(wstr);
 517                 if (wlen < 0) return;
 518         } else
 519                 wlen = new_text_length;
 520
 521         undo_add(text_to_insert, *position, *position + wlen,
 522                  UNDO_ACTION_INSERT, undostruct);
 523 }
 524
 525 void undo_delete_text_cb(GtkEditable *editable, gint start_pos,
 526                          gint end_pos, UndoMain *undostruct)
 527 {
 528         gchar *text_to_delete;
 529
 530         if (prefs_common.undolevels <= 0) return;
 531         if (start_pos == end_pos) return;
 532
 533         text_to_delete = gtk_editable_get_chars(GTK_EDITABLE(editable),
 534                                                 start_pos, end_pos);
 535         undo_add(text_to_delete, start_pos, end_pos, UNDO_ACTION_DELETE,
 536                  undostruct);
 537         g_free(text_to_delete);
 538 }
 539
 540 void undo_paste_clipboard_cb(GtkEditable *editable, UndoMain *undostruct)
 541 {
 542         if (editable->clipboard_text == NULL) return;
 543
 544         if (prefs_common.undolevels > 0)
 545                 if (undo_get_selection(editable, NULL, NULL))
 546                         undostruct->paste = TRUE;
 547 }
 548
 549 /**
 550  * undo_get_selection:
 551  * @text: Text to get the selection from
 552  * @start: return here the start position of the selection
 553  * @end: return here the end position of the selection
 554  *
 555  * Gets the current selection for View
 556  *
 557  * Return Value: TRUE if there is a selection active, FALSE if not
 558  **/
 559 static gint undo_get_selection(GtkEditable *text, guint *start, guint *end)
 560 {
 561         guint start_pos, end_pos;
 562
 563         start_pos = text->selection_start_pos;
 564         end_pos   = text->selection_end_pos;
 565
 566         /* The user can select from end to start too. If so, swap it*/
 567         if (end_pos < start_pos) {
 568                 guint swap_pos;
 569                 swap_pos  = end_pos;
 570                 end_pos   = start_pos;
 571                 start_pos = swap_pos;
 572         }
 573
 574         if (start != NULL)
 575                 *start = start_pos;
 576
 577         if (end != NULL)
 578                 *end = end_pos;
 579
 580         if ((start_pos > 0 || end_pos > 0) && (start_pos != end_pos))
 581                 return TRUE;
 582         else
 583                 return FALSE;
 584 }