mainundo.C

Go to the documentation of this file.

#include "asset.h"
#include "assets.h"
#include "edl.h"
#include "filexml.h"
#include "mainindexes.h"
#include "mainmenu.h"
#include "mainsession.h"
#include "mainundo.h"
#include "mwindow.h"
#include "mwindowgui.h"
#include "undostackitem.h"
#include <string.h>

// Minimum number of undoable operations on the undo stack
#define UNDOMINLEVELS 5
// Limits the bytes of memory used by the undo stack
#define UNDOMEMORY 50000000


class MainUndoStackItem : public UndoStackItem
{
public:
        MainUndoStackItem(MainUndo* undo, char* description,
                        uint32_t load_flags, void* creator);
        virtual ~MainUndoStackItem();

        void set_data_before(char *data);
        virtual void undo();
        virtual int get_size();

private:
// type of modification
        unsigned long load_flags;
        
// data before the modification for undos
        char *data_before;          

        MainUndo *main_undo;

        void load_from_undo(FileXML *file, uint32_t load_flags);        // loads undo from the stringfile to the project
};


MainUndo::MainUndo(MWindow *mwindow)
{ 
        this->mwindow = mwindow;
        new_entry = 0;
        data_after = 0;
        last_update = new Timer;

// get the initial project so we have something that the last undo reverts to
        capture_state();
}

MainUndo::~MainUndo()
{
        delete [] data_after;
        delete last_update;
}

void MainUndo::update_undo(char *description, uint32_t load_flags, 
                void *creator, int changes_made)
{
        if (ignore_push(description, load_flags, creator))
        {
                capture_state();
                return;
        }

        MainUndoStackItem* new_entry = new MainUndoStackItem(this, description, load_flags, creator);

// the old data_after is the state before the change
        new_entry->set_data_before(data_after);

        push_undo_item(new_entry);
}

void MainUndo::push_undo_item(UndoStackItem *item)
{
// clear redo_stack
        while (redo_stack.last)
                redo_stack.remove(redo_stack.last);

// move item onto undo_stack
        undo_stack.append(item);
        prune_undo();

        capture_state();

        mwindow->session->changes_made = 1;
   mwindow->gui->lock_window("MainUndo::update_undo_before");
   mwindow->gui->mainmenu->undo->update_caption(item->description);
   mwindow->gui->mainmenu->redo->update_caption("");
   mwindow->gui->unlock_window();
}

void MainUndo::capture_state()
{
        FileXML file;
        mwindow->edl->save_xml(mwindow->plugindb, 
                &file, 
                "",
                0,
                0);
        file.terminate_string();
        delete [] data_after;
        data_after = new char[strlen(file.string)+1];
        strcpy(data_after, file.string);
}

bool MainUndo::ignore_push(char *description, uint32_t load_flags, void* creator)
{
// ignore this push under certain conditions:
// - if nothing was undone
        bool ignore = redo_stack.last == 0 &&
// - if it is not the first push
                undo_stack.last &&
// - if it has the same description as the previous undo
                strcmp(undo_stack.last->description, description) == 0 &&
// - if it originates from the same creator
                undo_stack.last->creator == creator &&
// - if it follows closely after the previous undo
                last_update->get_difference() < 300 /*millisec*/;
        last_update->update();
        return ignore;
}

void MainUndo::push_state(char *description, uint32_t load_flags, void* creator)
{
        if (ignore_push(description, load_flags, creator))
        {
                capture_state();
        }
        else
        {
                MainUndoStackItem* new_entry = new MainUndoStackItem(this, description, load_flags, creator);
// the old data_after is the state before the change
                new_entry->set_data_before(data_after);
                push_undo_item(new_entry);
        }
        mwindow->session->changes_made = 1;
}






int MainUndo::undo()
{
        UndoStackItem* current_entry = undo_stack.last;

        if(current_entry)
        {
// move item to redo_stack
                undo_stack.remove_pointer(current_entry);
                current_entry->undo();
                redo_stack.append(current_entry);
                capture_state();

                if(mwindow->gui)
                {
                        mwindow->gui->mainmenu->redo->update_caption(current_entry->description);

                        if(undo_stack.last)
                                mwindow->gui->mainmenu->undo->update_caption(undo_stack.last->description);
                        else
                                mwindow->gui->mainmenu->undo->update_caption("");
                }
        }

        reset_creators();
        return 0;
}

int MainUndo::redo()
{
        UndoStackItem* current_entry = redo_stack.last;
        
        if(current_entry)
        {
// move item to undo_stack
                redo_stack.remove_pointer(current_entry);
                current_entry->undo();
                undo_stack.append(current_entry);
                capture_state();

                if(mwindow->gui)
                {
                        mwindow->gui->mainmenu->undo->update_caption(current_entry->description);
                        
                        if(redo_stack.last)
                                mwindow->gui->mainmenu->redo->update_caption(redo_stack.last->description);
                        else
                                mwindow->gui->mainmenu->redo->update_caption("");
                }
        }
        reset_creators();
        return 0;
}

// enforces that the undo stack does not exceed a size of UNDOMEMORY
// except that it always has at least UNDOMINLEVELS entries
void MainUndo::prune_undo()
{
        int size = 0;
        int levels = 0;

        UndoStackItem* i = undo_stack.last;
        while (i != 0 && (levels < UNDOMINLEVELS || size <= UNDOMEMORY))
        {
                size += i->get_size();
                ++levels;
                i = i->previous;
        }

        if (i != 0)
        {
// truncate everything before and including i
                while (undo_stack.first != i)
                        undo_stack.remove(undo_stack.first);
                undo_stack.remove(undo_stack.first);
        }
}





MainUndoStackItem::MainUndoStackItem(MainUndo* main_undo, char* description,
                        uint32_t load_flags, void* creator)
{
        data_before = 0;
        this->load_flags = load_flags;
        this->main_undo = main_undo;
        set_description(description);
        set_creator(creator);
}

MainUndoStackItem::~MainUndoStackItem()
{
        delete [] data_before;
}

void MainUndoStackItem::set_data_before(char *data)
{
        data_before = new char[strlen(data) + 1];
        strcpy(data_before, data);
}

void MainUndoStackItem::undo()
{
// move the old data_after here
        char* before = data_before;
        data_before = 0;
        set_data_before(main_undo->data_after);

// undo the state
        FileXML file;

        file.read_from_string(before);
        load_from_undo(&file, load_flags);
}

int MainUndoStackItem::get_size()
{
        return data_before ? strlen(data_before) : 0;
}

// Here the master EDL loads 
void MainUndoStackItem::load_from_undo(FileXML *file, uint32_t load_flags)
{
        MWindow* mwindow = main_undo->mwindow;
        mwindow->edl->load_xml(mwindow->plugindb, file, load_flags);
        for(Asset *asset = mwindow->edl->assets->first;
                asset;
                asset = asset->next)
        {
                mwindow->mainindexes->add_next_asset(0, asset);
        }
        mwindow->mainindexes->start_build();
}


void MainUndo::reset_creators()
{
        for(UndoStackItem *current = undo_stack.first;
                current;
                current = NEXT)
        {
                current->set_creator(0);
        }
}

---