paint_undo.c

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/*
 *
 * Undo system for painting and sculpting.
 * 
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <stdlib.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "BLI_listbase.h"
#include "BLI_utildefines.h"
#include "BLI_string.h"

#include "DNA_userdef_types.h"


#include "BKE_context.h"
#include "BKE_global.h"

#include "ED_sculpt.h"

#include "paint_intern.h"

#define MAXUNDONAME 64

typedef struct UndoElem {
    struct UndoElem *next, *prev;
    char name[MAXUNDONAME];
    uintptr_t undosize;

    ListBase elems;

    UndoRestoreCb restore;
    UndoFreeCb free;
} UndoElem;

typedef struct UndoStack {
    int type;
    ListBase elems;
    UndoElem *current;
} UndoStack;

static UndoStack ImageUndoStack = {UNDO_PAINT_IMAGE, {NULL, NULL}, NULL};
static UndoStack MeshUndoStack = {UNDO_PAINT_MESH, {NULL, NULL}, NULL};

/* Generic */

static void undo_restore(bContext *C, UndoStack *UNUSED(stack), UndoElem *uel)
{
    if(uel && uel->restore)
        uel->restore(C, &uel->elems);
}

static void undo_elem_free(UndoStack *UNUSED(stack), UndoElem *uel)
{
    if(uel && uel->free) {
        uel->free(&uel->elems);
        BLI_freelistN(&uel->elems);
    }
}

static void undo_stack_push_begin(UndoStack *stack, const char *name, UndoRestoreCb restore, UndoFreeCb free)
{
    UndoElem *uel;
    int nr;
    
    /* Undo push is split up in begin and end, the reason is that as painting
     * happens more tiles/nodes are added to the list, and at the very end we
     * know how much memory the undo used to remove old undo elements */

    /* remove all undos after (also when stack->current==NULL) */
    while(stack->elems.last != stack->current) {
        uel= stack->elems.last;
        undo_elem_free(stack, uel);
        BLI_freelinkN(&stack->elems, uel);
    }
    
    /* make new */
    stack->current= uel= MEM_callocN(sizeof(UndoElem), "undo file");
    uel->restore= restore;
    uel->free= free;
    BLI_addtail(&stack->elems, uel);

    /* name can be a dynamic string */
    BLI_strncpy(uel->name, name, sizeof(uel->name));
    
    /* limit amount to the maximum amount*/
    nr= 0;
    uel= stack->elems.last;
    while(uel) {
        nr++;
        if(nr==U.undosteps) break;
        uel= uel->prev;
    }
    if(uel) {
        while(stack->elems.first!=uel) {
            UndoElem *first= stack->elems.first;
            undo_elem_free(stack, first);
            BLI_freelinkN(&stack->elems, first);
        }
    }
}

static void undo_stack_push_end(UndoStack *stack)
{
    UndoElem *uel;
    uintptr_t totmem, maxmem;

    if(U.undomemory != 0) {
        /* limit to maximum memory (afterwards, we can't know in advance) */
        totmem= 0;
        maxmem= ((uintptr_t)U.undomemory)*1024*1024;

        uel= stack->elems.last;
        while(uel) {
            totmem+= uel->undosize;
            if(totmem>maxmem) break;
            uel= uel->prev;
        }

        if(uel) {
            while(stack->elems.first!=uel) {
                UndoElem *first= stack->elems.first;
                undo_elem_free(stack, first);
                BLI_freelinkN(&stack->elems, first);
            }
        }
    }
}

static int undo_stack_step(bContext *C, UndoStack *stack, int step, const char *name)
{
    UndoElem *undo;

    if(step==1) {
        if(stack->current==NULL);
        else {
            if(!name || strcmp(stack->current->name, name) == 0) {
                if(G.f & G_DEBUG) printf("undo %s\n", stack->current->name);
                undo_restore(C, stack, stack->current);
                stack->current= stack->current->prev;
                return 1;
            }
        }
    }
    else if(step==-1) {
        if((stack->current!=NULL && stack->current->next==NULL) || stack->elems.first==NULL);
        else {
            if(!name || strcmp(stack->current->name, name) == 0) {
                undo= (stack->current && stack->current->next)? stack->current->next: stack->elems.first;
                undo_restore(C, stack, undo);
                stack->current= undo;
                if(G.f & G_DEBUG) printf("redo %s\n", undo->name);
                return 1;
            }
        }
    }

    return 0;
}

static void undo_stack_free(UndoStack *stack)
{
    UndoElem *uel;
    
    for(uel=stack->elems.first; uel; uel=uel->next)
        undo_elem_free(stack, uel);

    BLI_freelistN(&stack->elems);
    stack->current= NULL;
}

/* Exported Functions */

void undo_paint_push_begin(int type, const char *name, UndoRestoreCb restore, UndoFreeCb free)
{
    if(type == UNDO_PAINT_IMAGE)
        undo_stack_push_begin(&ImageUndoStack, name, restore, free);
    else if(type == UNDO_PAINT_MESH)
        undo_stack_push_begin(&MeshUndoStack, name, restore, free);
}

ListBase *undo_paint_push_get_list(int type)
{
    if(type == UNDO_PAINT_IMAGE) {
        if(ImageUndoStack.current)
            return &ImageUndoStack.current->elems;
    }
    else if(type == UNDO_PAINT_MESH) {
        if(MeshUndoStack.current)
            return &MeshUndoStack.current->elems;
    }
    
    return NULL;
}

void undo_paint_push_count_alloc(int type, int size)
{
    if(type == UNDO_PAINT_IMAGE)
        ImageUndoStack.current->undosize += size;
    else if(type == UNDO_PAINT_MESH)
        MeshUndoStack.current->undosize += size;
}

void undo_paint_push_end(int type)
{
    if(type == UNDO_PAINT_IMAGE)
        undo_stack_push_end(&ImageUndoStack);
    else if(type == UNDO_PAINT_MESH)
        undo_stack_push_end(&MeshUndoStack);
}

int ED_undo_paint_step(bContext *C, int type, int step, const char *name)
{
    if(type == UNDO_PAINT_IMAGE)
        return undo_stack_step(C, &ImageUndoStack, step, name);
    else if(type == UNDO_PAINT_MESH)
        return undo_stack_step(C, &MeshUndoStack, step, name);
    
    return 0;
}

int ED_undo_paint_valid(int type, const char *name)
{
    UndoStack *stack;
    
    if(type == UNDO_PAINT_IMAGE)
        stack= &ImageUndoStack;
    else if(type == UNDO_PAINT_MESH)
        stack= &MeshUndoStack;
    else 
        return 0;
    
    if(stack->current==NULL);
    else {
        if(name && strcmp(stack->current->name, name) == 0)
            return 1;
        else
            return stack->elems.first != stack->elems.last;
    }
    return 0;
}

void ED_undo_paint_free(void)
{
    undo_stack_free(&ImageUndoStack);
    undo_stack_free(&MeshUndoStack);
}