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