app/undo.c

   1 /* Dia -- an diagram creation/manipulation program
   2  * Copyright (C) 1999 Alexander Larsson
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  */
  18
  19 #include <config.h>
  20
  21 #include "undo.h"
  22 #include "object_ops.h"
  23 #include "properties.h"
  24 #include "connectionpoint_ops.h"
  25 #include "focus.h"
  26 #include "group.h"
  27 #include "preferences.h"
  28 #include "diagram_tree_window.h"
  29
  30 #if 0
  31 #define DEBUG_PRINTF(args) printf args
  32 #else
  33 #define DEBUG_PRINTF(args)
  34 #endif
  35
  36 static void
  37 transaction_point_pointer(Change *change, Diagram *dia)
  38 {
  39   /* Empty function used to track transactionpoints. */
  40 }
  41
  42 static int
  43 is_transactionpoint(Change *change)
  44 {
  45   return change->apply == transaction_point_pointer;
  46 }
  47
  48 static Change *
  49 new_transactionpoint(void)
  50 {
  51   Change *transaction = g_new(Change, 1);
  52
  53   if (transaction) {
  54     transaction->apply = transaction_point_pointer;
  55     transaction->revert = transaction_point_pointer;
  56     transaction->free = NULL;
  57   }
  58
  59   return transaction;
  60 }
  61
  62 UndoStack *
  63 new_undo_stack(Diagram *dia)
  64 {
  65   UndoStack *stack;
  66   Change *transaction;
  67
  68   stack = g_new(UndoStack, 1);
  69   if (stack!=NULL){
  70     stack->dia = dia;
  71     transaction = new_transactionpoint();
  72     transaction->next = transaction->prev = NULL;
  73     stack->last_change = transaction;
  74     stack->current_change = transaction;
  75     stack->last_save = transaction;
  76     stack->depth = 0;
  77   }
  78   return stack;
  79 }
  80
  81 void
  82 undo_destroy(UndoStack *stack)
  83 {
  84   undo_clear(stack);
  85   g_free(stack->current_change); /* Free first transaction point. */
  86   g_free(stack);
  87 }
  88
  89
  90
  91 static void
  92 undo_remove_redo_info(UndoStack *stack)
  93 {
  94   Change *change;
  95   Change *next_change;
  96
  97   DEBUG_PRINTF(("UNDO: Removing redo info\n"));
  98
  99   change = stack->current_change->next;
 100   stack->current_change->next = NULL;
 101   stack->last_change = stack->current_change;
 102
 103   while (change != NULL) {
 104     next_change = change->next;
 105     if (change->free)
 106       (change->free)(change);
 107     g_free(change);
 108     change = next_change;
 109   }
 110 }
 111
 112 static int
 113 depth(UndoStack *stack)
 114 {
 115   int i;
 116   Change *change;
 117   change = stack->current_change;
 118
 119   i = 0;
 120   while (change->prev != NULL) {
 121     change = change->prev;
 122     i++;
 123   }
 124   return i;
 125 }
 126
 127 void
 128 undo_push_change(UndoStack *stack, Change *change)
 129 {
 130   if (stack->current_change != stack->last_change)
 131     undo_remove_redo_info(stack);
 132
 133   DEBUG_PRINTF(("UNDO: Push new change at %d\n", depth(stack)));
 134
 135   change->prev = stack->last_change;
 136   change->next = NULL;
 137   stack->last_change->next = change;
 138   stack->last_change = change;
 139   stack->current_change = change;
 140 }
 141
 142 static void
 143 undo_delete_lowest_transaction(UndoStack *stack)
 144 {
 145   Change *change;
 146   Change *next_change;
 147
 148   /* Find the lowest change: */
 149   change = stack->current_change;
 150   while (change->prev != NULL) {
 151     change = change->prev;
 152   }
 153
 154   /* Remove changes from the bottom until (and including)
 155    * the first transactionpoint.
 156    * Stop if we reach current_change or NULL.
 157    */
 158   do {
 159     if ( (change == NULL) || (change == stack->current_change))
 160       break;
 161
 162     next_change = change->next;
 163     DEBUG_PRINTF(("freeing one change from the bottom.\n"));
 164     if (change->free)
 165       (change->free)(change);
 166     g_free(change);
 167     change = next_change;
 168   } while (!is_transactionpoint(change));
 169
 170   if (is_transactionpoint(change)) {
 171     stack->depth--;
 172     DEBUG_PRINTF(("Decreasing stack depth to: %d\n", stack->depth));
 173   }
 174   change->prev = NULL;
 175 }
 176
 177 void
 178 undo_set_transactionpoint(UndoStack *stack)
 179 {
 180   Change *transaction;
 181
 182   if (is_transactionpoint(stack->current_change))
 183     return;
 184
 185   DEBUG_PRINTF(("UNDO: Push new transactionpoint at %d\n", depth(stack)));
 186
 187   transaction = new_transactionpoint();
 188
 189   undo_push_change(stack, transaction);
 190   stack->depth++;
 191   DEBUG_PRINTF(("Increasing stack depth to: %d\n", stack->depth));
 192
 193   if (prefs.undo_depth > 0) {
 194     while (stack->depth > prefs.undo_depth){
 195       undo_delete_lowest_transaction(stack);
 196     }
 197   }
 198 }
 199
 200 void
 201 undo_revert_to_last_tp(UndoStack *stack)
 202 {
 203   Change *change;
 204   Change *prev_change;
 205
 206   if (stack->current_change->prev == NULL)
 207     return; /* Can't revert first transactionpoint */
 208
 209   change = stack->current_change;
 210   do {
 211     prev_change = change->prev;
 212     (change->revert)(change, stack->dia);
 213     change = prev_change;
 214   } while (!is_transactionpoint(change));
 215   stack->current_change  = change;
 216   stack->depth--;
 217   DEBUG_PRINTF(("Decreasing stack depth to: %d\n", stack->depth));
 218 }
 219
 220 void
 221 undo_apply_to_next_tp(UndoStack *stack)
 222 {
 223   Change *change;
 224   Change *next_change;
 225
 226   change = stack->current_change;
 227
 228   if (change->next == NULL)
 229     return /* Already at top. */;
 230
 231   do {
 232     next_change = change->next;
 233     (change->apply)(change, stack->dia);
 234     change = next_change;
 235   } while ( (change != NULL) &&
 236             (!is_transactionpoint(change)) );
 237   if (change == NULL)
 238     change = stack->last_change;
 239   stack->current_change = change;
 240   stack->depth++;
 241   DEBUG_PRINTF(("Increasing stack depth to: %d\n", stack->depth));
 242 }
 243
 244
 245 void
 246 undo_clear(UndoStack *stack)
 247 {
 248   Change *change;
 249
 250   DEBUG_PRINTF(("undo_clear()\n"));
 251
 252   change = stack->current_change;
 253
 254   while (change->prev != NULL) {
 255     change = change->prev;
 256   }
 257
 258   stack->current_change = change;
 259   stack->depth = 0;
 260   undo_remove_redo_info(stack);
 261 }
 262
 263 /** Marks the undo stack at the time of a save.
 264  */
 265 void
 266 undo_mark_save(UndoStack *stack)
 267 {
 268   stack->last_save = stack->current_change;
 269 }
 270
 271 /** Returns true if the diagram is undo-wise in the same state as at
 272  * last save, i.e. the current change is the same as it was at last save.
 273  */
 274 gboolean
 275 undo_is_saved(UndoStack *stack)
 276 {
 277   return stack->last_save == stack->current_change;
 278 }
 279
 280
 281
 282 /****************************************************************/
 283 /****************************************************************/
 284 /*****************                          *********************/
 285 /***************** Specific undo functions: *********************/
 286 /*****************                          *********************/
 287 /****************************************************************/
 288 /****************************************************************/
 289
 290 /******** Move object list: */
 291
 292 struct MoveObjectsChange {
 293   Change change;
 294
 295   Point *orig_pos;
 296   Point *dest_pos;
 297   GList *obj_list;
 298 };
 299
 300 static void
 301 move_objects_apply(struct MoveObjectsChange *change, Diagram *dia)
 302 {
 303   GList *list;
 304   int i;
 305   Object *obj;
 306
 307   object_add_updates_list(change->obj_list, dia);
 308
 309   list = change->obj_list;
 310   i=0;
 311   while (list != NULL) {
 312     obj = (Object *)  list->data;
 313
 314     obj->ops->move(obj, &change->dest_pos[i]);
 315
 316     list = g_list_next(list); i++;
 317   }
 318
 319   list = change->obj_list;
 320   while (list!=NULL) {
 321     obj = (Object *) list->data;
 322
 323     diagram_update_connections_object(dia, obj, TRUE);
 324
 325     list = g_list_next(list);
 326   }
 327
 328   object_add_updates_list(change->obj_list, dia);
 329 }
 330
 331 static void
 332 move_objects_revert(struct MoveObjectsChange *change, Diagram *dia)
 333 {
 334   GList *list;
 335   int i;
 336   Object *obj;
 337
 338   object_add_updates_list(change->obj_list, dia);
 339
 340   list = change->obj_list;
 341   i=0;
 342   while (list != NULL) {
 343     obj = (Object *)  list->data;
 344
 345     obj->ops->move(obj, &change->orig_pos[i]);
 346
 347     list = g_list_next(list); i++;
 348   }
 349
 350   list = change->obj_list;
 351   while (list!=NULL) {
 352     obj = (Object *) list->data;
 353
 354     diagram_update_connections_object(dia, obj, TRUE);
 355
 356     list = g_list_next(list);
 357   }
 358
 359   object_add_updates_list(change->obj_list, dia);
 360 }
 361
 362 static void
 363 move_objects_free(struct MoveObjectsChange *change)
 364 {
 365   g_free(change->orig_pos);
 366   g_free(change->dest_pos);
 367   g_list_free(change->obj_list);
 368 }
 369
 370 extern Change *
 371 undo_move_objects(Diagram *dia, Point *orig_pos, Point *dest_pos,
 372                   GList *obj_list)
 373 {
 374   struct MoveObjectsChange *change;
 375
 376   change = g_new(struct MoveObjectsChange, 1);
 377
 378   change->change.apply = (UndoApplyFunc) move_objects_apply;
 379   change->change.revert = (UndoRevertFunc) move_objects_revert;
 380   change->change.free = (UndoFreeFunc) move_objects_free;
 381
 382   change->orig_pos = orig_pos;
 383   change->dest_pos = dest_pos;
 384   change->obj_list = obj_list;
 385
 386   DEBUG_PRINTF(("UNDO: Push new move objects at %d\n", depth(dia->undo)));
 387   undo_push_change(dia->undo, (Change *) change);
 388   return (Change *)change;
 389 }
 390
 391 /********** Move handle: */
 392
 393 struct MoveHandleChange {
 394   Change change;
 395
 396   Point orig_pos;
 397   Point dest_pos;
 398   Handle *handle;
 399   Object *obj;
 400 };
 401
 402 static void
 403 move_handle_apply(struct MoveHandleChange *change, Diagram *dia)
 404 {
 405   object_add_updates(change->obj, dia);
 406   change->obj->ops->move_handle(change->obj, change->handle,
 407                                 &change->dest_pos, NULL,
 408                                 HANDLE_MOVE_USER_FINAL, 0);
 409   object_add_updates(change->obj, dia);
 410   diagram_update_connections_object(dia, change->obj, TRUE);
 411 }
 412
 413 static void
 414 move_handle_revert(struct MoveHandleChange *change, Diagram *dia)
 415 {
 416   object_add_updates(change->obj, dia);
 417   change->obj->ops->move_handle(change->obj, change->handle,
 418                                 &change->orig_pos, NULL,
 419                                 HANDLE_MOVE_USER_FINAL, 0);
 420   object_add_updates(change->obj, dia);
 421   diagram_update_connections_object(dia, change->obj, TRUE);
 422 }
 423
 424 static void
 425 move_handle_free(struct MoveHandleChange *change)
 426 {
 427 }
 428
 429
 430 Change *
 431 undo_move_handle(Diagram *dia,
 432                  Handle *handle, Object *obj,
 433                  Point orig_pos, Point dest_pos)
 434 {
 435   struct MoveHandleChange *change;
 436
 437   change = g_new(struct MoveHandleChange, 1);
 438
 439   change->change.apply = (UndoApplyFunc) move_handle_apply;
 440   change->change.revert = (UndoRevertFunc) move_handle_revert;
 441   change->change.free = (UndoFreeFunc) move_handle_free;
 442
 443   change->orig_pos = orig_pos;
 444   change->dest_pos = dest_pos;
 445   change->handle = handle;
 446   change->obj = obj;
 447
 448   DEBUG_PRINTF(("UNDO: Push new move handle at %d\n", depth(dia->undo)));
 449
 450   undo_push_change(dia->undo, (Change *) change);
 451   return (Change *)change;
 452 }
 453
 454 /***************** Connect object: */
 455
 456 struct ConnectChange {
 457   Change change;
 458
 459   Object *obj;
 460   Handle *handle;
 461   ConnectionPoint *connectionpoint;
 462   Point handle_pos;
 463 };
 464
 465 static void
 466 connect_apply(struct ConnectChange *change, Diagram *dia)
 467 {
 468   object_connect(change->obj, change->handle, change->connectionpoint);
 469
 470   object_add_updates(change->obj, dia);
 471   change->obj->ops->move_handle(change->obj, change->handle ,
 472                                 &change->connectionpoint->pos,
 473                                 change->connectionpoint,
 474                                 HANDLE_MOVE_CONNECTED, 0);
 475
 476   object_add_updates(change->obj, dia);
 477 }
 478
 479 static void
 480 connect_revert(struct ConnectChange *change, Diagram *dia)
 481 {
 482   object_unconnect(change->obj, change->handle);
 483
 484   object_add_updates(change->obj, dia);
 485   change->obj->ops->move_handle(change->obj, change->handle ,
 486                                 &change->handle_pos, NULL,
 487                                 HANDLE_MOVE_CONNECTED, 0);
 488
 489   object_add_updates(change->obj, dia);
 490 }
 491
 492 static void
 493 connect_free(struct ConnectChange *change)
 494 {
 495 }
 496
 497 extern Change *
 498 undo_connect(Diagram *dia, Object *obj, Handle *handle,
 499              ConnectionPoint *connectionpoint)
 500 {
 501   struct ConnectChange *change;
 502
 503   change = g_new(struct ConnectChange, 1);
 504
 505   change->change.apply = (UndoApplyFunc) connect_apply;
 506   change->change.revert = (UndoRevertFunc) connect_revert;
 507   change->change.free = (UndoFreeFunc) connect_free;
 508
 509   change->obj = obj;
 510   change->handle = handle;
 511   change->handle_pos = handle->pos;
 512   change->connectionpoint = connectionpoint;
 513
 514   DEBUG_PRINTF(("UNDO: Push new connect at %d\n", depth(dia->undo)));
 515   undo_push_change(dia->undo, (Change *) change);
 516   return (Change *)change;
 517 }
 518
 519 /*************** Unconnect object: */
 520
 521 struct UnconnectChange {
 522   Change change;
 523
 524   Object *obj;
 525   Handle *handle;
 526   ConnectionPoint *connectionpoint;
 527 };
 528
 529 static void
 530 unconnect_apply(struct UnconnectChange *change, Diagram *dia)
 531 {
 532   object_unconnect(change->obj, change->handle);
 533
 534   object_add_updates(change->obj, dia);
 535 }
 536
 537 static void
 538 unconnect_revert(struct UnconnectChange *change, Diagram *dia)
 539 {
 540   object_connect(change->obj, change->handle, change->connectionpoint);
 541
 542   object_add_updates(change->obj, dia);
 543 }
 544
 545 static void
 546 unconnect_free(struct UnconnectChange *change)
 547 {
 548 }
 549
 550 extern Change *
 551 undo_unconnect(Diagram *dia, Object *obj, Handle *handle)
 552 {
 553   struct UnconnectChange *change;
 554
 555   change = g_new(struct UnconnectChange, 1);
 556
 557   change->change.apply = (UndoApplyFunc) unconnect_apply;
 558   change->change.revert = (UndoRevertFunc) unconnect_revert;
 559   change->change.free = (UndoFreeFunc) unconnect_free;
 560
 561   change->obj = obj;
 562   change->handle = handle;
 563   change->connectionpoint = handle->connected_to;
 564
 565   DEBUG_PRINTF(("UNDO: Push new unconnect at %d\n", depth(dia->undo)));
 566   undo_push_change(dia->undo, (Change *) change);
 567   return (Change *)change;
 568 }
 569
 570
 571 /******** Delete object list: */
 572
 573 struct DeleteObjectsChange {
 574   Change change;
 575
 576   Layer *layer;
 577   GList *obj_list; /* Owning reference when applied */
 578   GList *original_objects;
 579   int applied;
 580 };
 581
 582 static void
 583 delete_objects_apply(struct DeleteObjectsChange *change, Diagram *dia)
 584 {
 585   GList *list;
 586
 587   DEBUG_PRINTF(("delete_objects_apply()\n"));
 588   change->applied = 1;
 589   diagram_unselect_objects(dia, change->obj_list);
 590   layer_remove_objects(change->layer, change->obj_list);
 591   object_add_updates_list(change->obj_list, dia);
 592
 593   list = change->obj_list;
 594   while (list != NULL) {
 595     Object *obj = (Object *)list->data;
 596
 597   /* Have to hide any open properties dialog
 598      if it contains some object in cut_list */
 599     properties_hide_if_shown(dia, obj);
 600
 601     /* Remove focus if active */
 602     if ((active_focus()!=NULL) && (active_focus()->obj == obj)) {
 603       remove_focus();
 604     }
 605
 606     if (obj->parent) /* Lose references to deleted object */
 607       obj->parent->children = g_list_remove(obj->parent->children, obj);
 608
 609     list = g_list_next(list);
 610   }
 611
 612   diagram_tree_remove_objects(diagram_tree(), change->obj_list);
 613 }
 614
 615 static void
 616 delete_objects_revert(struct DeleteObjectsChange *change, Diagram *dia)
 617 {
 618   GList *list;
 619   DEBUG_PRINTF(("delete_objects_revert()\n"));
 620   change->applied = 0;
 621   layer_set_object_list(change->layer,
 622                         g_list_copy(change->original_objects));
 623   object_add_updates_list(change->obj_list, dia);
 624
 625  list = change->obj_list;
 626  while (list)
 627  {
 628    Object *obj = (Object *) list->data;
 629    if (obj->parent) /* Restore child references */
 630         obj->parent->children = g_list_append(obj->parent->children, obj);
 631
 632   list = g_list_next(list);
 633  }
 634
 635   diagram_tree_add_objects(diagram_tree(), dia, change->obj_list);
 636 }
 637
 638 static void
 639 delete_objects_free(struct DeleteObjectsChange *change)
 640 {
 641   DEBUG_PRINTF(("delete_objects_free()\n"));
 642   if (change->applied)
 643     destroy_object_list(change->obj_list);
 644   else
 645     g_list_free(change->obj_list);
 646   g_list_free(change->original_objects);
 647 }
 648
 649 /*
 650   This function deletes specified objects along with any children
 651   they might have.
 652   undo_delete_objects() only deletes the objects that are specified.
 653 */
 654 Change *
 655 undo_delete_objects_children(Diagram *dia, GList *obj_list)
 656 {
 657   return undo_delete_objects(dia, parent_list_affected(obj_list));
 658 }
 659
 660 Change *
 661 undo_delete_objects(Diagram *dia, GList *obj_list)
 662 {
 663   struct DeleteObjectsChange *change;
 664
 665   change = g_new(struct DeleteObjectsChange, 1);
 666
 667   change->change.apply = (UndoApplyFunc) delete_objects_apply;
 668   change->change.revert = (UndoRevertFunc) delete_objects_revert;
 669   change->change.free = (UndoFreeFunc) delete_objects_free;
 670
 671   change->layer = dia->data->active_layer;
 672   change->obj_list = obj_list;
 673   change->original_objects = g_list_copy(dia->data->active_layer->objects);
 674   change->applied = 0;
 675
 676   DEBUG_PRINTF(("UNDO: Push new delete objects at %d\n", depth(dia->undo)));
 677   undo_push_change(dia->undo, (Change *) change);
 678   return (Change *)change;
 679 }
 680
 681 /******** Insert object list: */
 682
 683 struct InsertObjectsChange {
 684   Change change;
 685
 686   Layer *layer;
 687   GList *obj_list; /* Owning reference when not applied */
 688   int applied;
 689 };
 690
 691 static void
 692 insert_objects_apply(struct InsertObjectsChange *change, Diagram *dia)
 693 {
 694   DEBUG_PRINTF(("insert_objects_apply()\n"));
 695   change->applied = 1;
 696   layer_add_objects(change->layer, g_list_copy(change->obj_list));
 697   object_add_updates_list(change->obj_list, dia);
 698   diagram_tree_add_objects(diagram_tree(), dia, change->obj_list);
 699 }
 700
 701 static void
 702 insert_objects_revert(struct InsertObjectsChange *change, Diagram *dia)
 703 {
 704   GList *list;
 705
 706   DEBUG_PRINTF(("insert_objects_revert()\n"));
 707   change->applied = 0;
 708   diagram_unselect_objects(dia, change->obj_list);
 709   layer_remove_objects(change->layer, change->obj_list);
 710   object_add_updates_list(change->obj_list, dia);
 711
 712   list = change->obj_list;
 713   while (list != NULL) {
 714     Object *obj = (Object *)list->data;
 715
 716   /* Have to hide any open properties dialog
 717      if it contains some object in cut_list */
 718     properties_hide_if_shown(dia, obj);
 719
 720     /* Remove focus if active */
 721     if ((active_focus()!=NULL) && (active_focus()->obj == obj)) {
 722       remove_focus();
 723     }
 724
 725     list = g_list_next(list);
 726   }
 727
 728   diagram_tree_remove_objects(diagram_tree(), change->obj_list);
 729 }
 730
 731 static void
 732 insert_objects_free(struct InsertObjectsChange *change)
 733 {
 734   DEBUG_PRINTF(("insert_objects_free()\n"));
 735   if (!change->applied)
 736     destroy_object_list(change->obj_list);
 737   else
 738     g_list_free(change->obj_list);
 739 }
 740
 741 Change *
 742 undo_insert_objects(Diagram *dia, GList *obj_list, int applied)
 743 {
 744   struct InsertObjectsChange *change;
 745
 746   change = g_new(struct InsertObjectsChange, 1);
 747
 748   change->change.apply = (UndoApplyFunc) insert_objects_apply;
 749   change->change.revert = (UndoRevertFunc) insert_objects_revert;
 750   change->change.free = (UndoFreeFunc) insert_objects_free;
 751
 752   change->layer = dia->data->active_layer;
 753   change->obj_list = obj_list;
 754   change->applied = applied;
 755
 756   DEBUG_PRINTF(("UNDO: Push new insert objects at %d\n", depth(dia->undo)));
 757   undo_push_change(dia->undo, (Change *) change);
 758   return (Change *)change;
 759 }
 760
 761 /******** Reorder object list: */
 762
 763 struct ReorderObjectsChange {
 764   Change change;
 765
 766   Layer *layer;
 767   GList *changed_list; /* Owning reference when applied */
 768   GList *original_objects;
 769   GList *reordered_objects;
 770 };
 771
 772 static void
 773 reorder_objects_apply(struct ReorderObjectsChange *change, Diagram *dia)
 774 {
 775   DEBUG_PRINTF(("reorder_objects_apply()\n"));
 776   layer_set_object_list(change->layer,
 777                         g_list_copy(change->reordered_objects));
 778   object_add_updates_list(change->changed_list, dia);
 779 }
 780
 781 static void
 782 reorder_objects_revert(struct ReorderObjectsChange *change, Diagram *dia)
 783 {
 784   DEBUG_PRINTF(("reorder_objects_revert()\n"));
 785   layer_set_object_list(change->layer,
 786                         g_list_copy(change->original_objects));
 787   object_add_updates_list(change->changed_list, dia);
 788 }
 789
 790 static void
 791 reorder_objects_free(struct ReorderObjectsChange *change)
 792 {
 793   DEBUG_PRINTF(("reorder_objects_free()\n"));
 794   g_list_free(change->changed_list);
 795   g_list_free(change->original_objects);
 796   g_list_free(change->reordered_objects);
 797 }
 798
 799 Change *
 800 undo_reorder_objects(Diagram *dia, GList *changed_list, GList *orig_list)
 801 {
 802   struct ReorderObjectsChange *change;
 803
 804   change = g_new(struct ReorderObjectsChange, 1);
 805
 806   change->change.apply = (UndoApplyFunc) reorder_objects_apply;
 807   change->change.revert = (UndoRevertFunc) reorder_objects_revert;
 808   change->change.free = (UndoFreeFunc) reorder_objects_free;
 809
 810   change->layer = dia->data->active_layer;
 811   change->changed_list = changed_list;
 812   change->original_objects = orig_list;
 813   change->reordered_objects = g_list_copy(dia->data->active_layer->objects);
 814
 815   DEBUG_PRINTF(("UNDO: Push new reorder objects at %d\n", depth(dia->undo)));
 816   undo_push_change(dia->undo, (Change *) change);
 817   return (Change *)change;
 818 }
 819
 820 /******** ObjectChange: */
 821
 822 struct ObjectChangeChange {
 823   Change change;
 824
 825   Object *obj;
 826   ObjectChange *obj_change;
 827 };
 828
 829
 830 static void
 831 object_change_apply(struct ObjectChangeChange *change,
 832                     Diagram *dia)
 833 {
 834   object_add_updates(change->obj, dia);
 835   change->obj_change->apply(change->obj_change, change->obj);
 836   { /* Make sure object updates its data: */
 837     Point p = change->obj->position;
 838     (change->obj->ops->move)(change->obj,&p);
 839   }
 840   object_add_updates(change->obj, dia);
 841
 842   diagram_update_connections_object(dia, change->obj, TRUE);
 843
 844   properties_update_if_shown(dia, change->obj);
 845 }
 846
 847 static void
 848 object_change_revert(struct ObjectChangeChange *change,
 849                      Diagram *dia)
 850 {
 851   object_add_updates(change->obj, dia);
 852   change->obj_change->revert(change->obj_change, change->obj);
 853   { /* Make sure object updates its data: */
 854     Point p = change->obj->position;
 855     (change->obj->ops->move)(change->obj,&p);
 856   }
 857   object_add_updates(change->obj, dia);
 858
 859   diagram_update_connections_object(dia, change->obj, TRUE);
 860
 861   properties_update_if_shown(dia, change->obj);
 862 }
 863
 864 static void
 865 object_change_free(struct ObjectChangeChange *change)
 866 {
 867   DEBUG_PRINTF(("state_change_free()\n"));
 868   if (change->obj_change->free)
 869     (*change->obj_change->free)(change->obj_change);
 870   g_free(change->obj_change);
 871 }
 872
 873 Change *
 874 undo_object_change(Diagram *dia, Object *obj,
 875                    ObjectChange *obj_change)
 876 {
 877   struct ObjectChangeChange *change;
 878
 879   change = g_new(struct ObjectChangeChange, 1);
 880
 881   change->change.apply = (UndoApplyFunc) object_change_apply;
 882   change->change.revert = (UndoRevertFunc) object_change_revert;
 883   change->change.free = (UndoFreeFunc) object_change_free;
 884
 885   change->obj = obj;
 886   change->obj_change = obj_change;
 887
 888   DEBUG_PRINTF(("UNDO: Push new obj_change at %d\n", depth(dia->undo)));
 889   undo_push_change(dia->undo, (Change *) change);
 890   return (Change *)change;
 891 }
 892
 893 /******** Group object list: */
 894
 895 /** Grouping and ungrouping are two subtly different changes:  While
 896  * ungrouping preserves the front/back position, grouping cannot do that,
 897  * since the act of grouping destroys positions for the members of the
 898  * group, and those positions have to be restored in the undo.
 899  */
 900
 901 struct GroupObjectsChange {
 902   Change change;
 903
 904   Layer *layer;
 905   Object *group;   /* owning reference if not applied */
 906   GList *obj_list; /* The list of objects in this group.  Owned by the
 907                       group */
 908   GList *orig_list; /* A copy of the original list of all objects,
 909                        from before the group was created.  Owned by
 910                        the group */
 911   int applied;
 912 };
 913
 914 static void
 915 group_objects_apply(struct GroupObjectsChange *change, Diagram *dia)
 916 {
 917   GList *list;
 918
 919   DEBUG_PRINTF(("group_objects_apply()\n"));
 920
 921   change->applied = 1;
 922
 923   diagram_unselect_objects(dia, change->obj_list);
 924   layer_remove_objects(change->layer, change->obj_list);
 925   layer_add_object(change->layer, change->group);
 926   object_add_updates(change->group, dia);
 927
 928   list = change->obj_list;
 929   while (list != NULL) {
 930     Object *obj = (Object *)list->data;
 931
 932   /* Have to hide any open properties dialog
 933      if it contains some object in cut_list */
 934     properties_hide_if_shown(dia, obj);
 935
 936     /* Remove focus if active */
 937     if ((active_focus()!=NULL) && (active_focus()->obj == obj)) {
 938       remove_focus();
 939     }
 940
 941     object_add_updates(obj, dia);
 942
 943     list = g_list_next(list);
 944   }
 945
 946   diagram_tree_add_object(diagram_tree(), dia, change->group);
 947   diagram_tree_remove_objects(diagram_tree(), change->obj_list);
 948 }
 949
 950 static void
 951 group_objects_revert(struct GroupObjectsChange *change, Diagram *dia)
 952 {
 953   GList *old_list;
 954
 955   DEBUG_PRINTF(("group_objects_revert()\n"));
 956   change->applied = 0;
 957
 958   diagram_unselect_object(dia, change->group);
 959   object_add_updates(change->group, dia);
 960
 961   layer_set_object_list(change->layer, g_list_copy(change->orig_list));
 962
 963   object_add_updates_list(change->obj_list, dia);
 964
 965   properties_hide_if_shown(dia, change->group);
 966
 967   diagram_tree_add_objects(diagram_tree(), dia, change->obj_list);
 968   diagram_tree_remove_object(diagram_tree(), change->group);
 969 }
 970
 971 static void
 972 group_objects_free(struct GroupObjectsChange *change)
 973 {
 974   DEBUG_PRINTF(("group_objects_free()\n"));
 975   if (!change->applied) {
 976     group_destroy_shallow(change->group);
 977     change->group = NULL;
 978     change->obj_list = NULL;
 979     /** Leak here? */
 980   }
 981   g_list_free(change->orig_list);
 982 }
 983
 984 Change *
 985 undo_group_objects(Diagram *dia, GList *obj_list, Object *group,
 986                    GList *orig_list)
 987 {
 988   struct GroupObjectsChange *change;
 989
 990   change = g_new(struct GroupObjectsChange, 1);
 991
 992   change->change.apply = (UndoApplyFunc) group_objects_apply;
 993   change->change.revert = (UndoRevertFunc) group_objects_revert;
 994   change->change.free = (UndoFreeFunc) group_objects_free;
 995
 996   change->layer = dia->data->active_layer;
 997   change->group = group;
 998   change->obj_list = obj_list;
 999   change->orig_list = orig_list;
1000   change->applied = 1;
1001
1002   DEBUG_PRINTF(("UNDO: Push new group objects at %d\n", depth(dia->undo)));
1003   undo_push_change(dia->undo, (Change *) change);
1004   return (Change *)change;
1005 }
1006
1007 /******** Ungroup object list: */
1008
1009 struct UngroupObjectsChange {
1010   Change change;
1011
1012   Layer *layer;
1013   Object *group;   /* owning reference if applied */
1014   GList *obj_list; /* This list is owned by the ungroup. */
1015   int group_index;
1016   int applied;
1017 };
1018
1019 static void
1020 ungroup_objects_apply(struct UngroupObjectsChange *change, Diagram *dia)
1021 {
1022   DEBUG_PRINTF(("ungroup_objects_apply()\n"));
1023
1024   change->applied = 1;
1025
1026   diagram_unselect_object(dia, change->group);
1027   object_add_updates(change->group, dia);
1028   layer_replace_object_with_list(change->layer, change->group,
1029                                  g_list_copy(change->obj_list));
1030   object_add_updates_list(change->obj_list, dia);
1031
1032   properties_hide_if_shown(dia, change->group);
1033
1034   diagram_tree_add_objects(diagram_tree(), dia, change->obj_list);
1035   diagram_tree_remove_object(diagram_tree(), change->group);
1036 }
1037
1038 static void
1039 ungroup_objects_revert(struct UngroupObjectsChange *change, Diagram *dia)
1040 {
1041   GList *list;
1042
1043   DEBUG_PRINTF(("ungroup_objects_revert()\n"));
1044   change->applied = 0;
1045
1046
1047   diagram_unselect_objects(dia, change->obj_list);
1048   layer_remove_objects(change->layer, change->obj_list);
1049   layer_add_object_at(change->layer, change->group, change->group_index);
1050   object_add_updates(change->group, dia);
1051
1052   list = change->obj_list;
1053   while (list != NULL) {
1054     Object *obj = (Object *)list->data;
1055
1056   /* Have to hide any open properties dialog
1057      if it contains some object in cut_list */
1058     properties_hide_if_shown(dia, obj);
1059
1060     /* Remove focus if active */
1061     if ((active_focus()!=NULL) && (active_focus()->obj == obj)) {
1062       remove_focus();
1063     }
1064
1065     object_add_updates(obj, dia);
1066
1067     list = g_list_next(list);
1068   }
1069
1070   diagram_tree_add_object(diagram_tree(), dia, change->group);
1071   diagram_tree_remove_objects(diagram_tree(), change->obj_list);
1072 }
1073
1074 static void
1075 ungroup_objects_free(struct UngroupObjectsChange *change)
1076 {
1077   DEBUG_PRINTF(("ungroup_objects_free()\n"));
1078   if (change->applied) {
1079     group_destroy_shallow(change->group);
1080     change->group = NULL;
1081     change->obj_list = NULL;
1082   }
1083 }
1084
1085 Change *
1086 undo_ungroup_objects(Diagram *dia, GList *obj_list, Object *group,
1087                      int group_index)
1088 {
1089   struct UngroupObjectsChange *change;
1090
1091   change = g_new(struct UngroupObjectsChange, 1);
1092
1093   change->change.apply = (UndoApplyFunc) ungroup_objects_apply;
1094   change->change.revert = (UndoRevertFunc) ungroup_objects_revert;
1095   change->change.free = (UndoFreeFunc) ungroup_objects_free;
1096
1097   change->layer = dia->data->active_layer;
1098   change->group = group;
1099   change->obj_list = obj_list;
1100   change->group_index = group_index;
1101   change->applied = 1;
1102
1103   DEBUG_PRINTF(("UNDO: Push new ungroup objects at %d\n", depth(dia->undo)));
1104   undo_push_change(dia->undo, (Change *) change);
1105   return (Change *)change;
1106 }
1107
1108 /******* PARENTING */
1109
1110 struct ParentChange {
1111   Change change;
1112   Object *parentobj, *childobj;
1113   gboolean parent;
1114 };
1115
1116 /** Performs the actual parenting of a child to a parent.
1117  * Since no display changes arise from this, we need call no update. */
1118 static void
1119 parent_object(Diagram *dia, Object *parent, Object *child)
1120 {
1121   child->parent = parent;
1122   parent->children = g_list_prepend(parent->children, child);
1123 }
1124
1125 /** Performs the actual removal of a child from a parent.
1126  * Since no display changes arise from this, we need call no update. */
1127 static void
1128 unparent_object(Diagram *dia, Object *parent, Object *child)
1129 {
1130   child->parent = NULL;
1131   parent->children = g_list_remove(parent->children, child);
1132 }
1133
1134 /** Applies the given ParentChange */
1135 static void
1136 parent_change_apply(Change *change, Diagram *dia)
1137 {
1138   struct ParentChange *parentchange = (struct ParentChange*)change;
1139   if (parentchange->parent) {
1140     parent_object(dia, parentchange->parentobj, parentchange->childobj);
1141   } else {
1142     unparent_object(dia, parentchange->parentobj, parentchange->childobj);
1143   }
1144 }
1145
1146 /** Reverts the given ParentChange */
1147 static void
1148 parent_change_revert(Change *change, Diagram *dia)
1149 {
1150   struct ParentChange *parentchange = (struct ParentChange*)change;
1151   if (!parentchange->parent) {
1152     parent_object(dia, parentchange->parentobj, parentchange->childobj);
1153   } else {
1154     unparent_object(dia, parentchange->parentobj, parentchange->childobj);
1155   }
1156 }
1157
1158 /** Frees items in the change -- none really */
1159 static void
1160 parent_change_free(Change *change)
1161 {
1162 }
1163
1164 /** Create a new Change object for parenting/unparenting.
1165  * `parent' is TRUE if applying this change makes childobj a
1166  * child of parentobj.
1167  */
1168 Change *
1169 undo_parenting(Diagram *dia, Object* parentobj, Object* childobj,
1170                gboolean parent)
1171 {
1172   struct ParentChange *parentchange = g_new0(struct ParentChange, 1);
1173   Change *change = (Change*)parentchange;
1174   change->apply = parent_change_apply;
1175   change->revert = parent_change_revert;
1176   change->free = parent_change_free;
1177
1178   parentchange->parentobj = parentobj;
1179   parentchange->childobj = childobj;
1180   parentchange->parent = parent;
1181
1182   DEBUG_PRINTF(("UNDO: Push new obj_change at %d\n", depth(dia->undo)));
1183   undo_push_change(dia->undo, change);
1184   return change;
1185 }