src/edithistory.h

/*
 *  LDForge: LDraw parts authoring CAD
 *  Copyright (C) 2013 - 2020 Teemu Piippo
 *
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 */

#pragma once
#include "main.h"
#include "model.h"

class AbstractHistoryEntry
{
public:
	virtual void undo(Model::EditContext& editContext) = 0;
	virtual void redo(Model::EditContext& editContext) = 0;
};

class InsertHistoryEntry : public AbstractHistoryEntry
{
public:
	InsertHistoryEntry(int position, const QByteArray& state) :
		position{position},
		state{state} {}
	void undo(Model::EditContext& editContext) override;
	void redo(Model::EditContext& editContext) override;
protected:
	int position;
	QByteArray state;
};

class DeleteHistoryEntry : public InsertHistoryEntry
{
public:
	void undo(Model::EditContext& editContext) override;
	void redo(Model::EditContext& editContext) override;
};

class EditHistoryEntry : public AbstractHistoryEntry
{
public:
	EditHistoryEntry(int position, const QByteArray& stateBefore, const QByteArray& stateAfter) :
		position{position},
		stateBefore{stateBefore},
		stateAfter{stateAfter} {}
	void undo(Model::EditContext& editContext) override;
	void redo(Model::EditContext& editContext) override;
private:
	int position;
	QByteArray stateBefore;
	QByteArray stateAfter;
};

class EditHistory
{
public:
	using Changeset = std::vector<std::unique_ptr<AbstractHistoryEntry>>;
	EditHistory();
	/**
	 * @brief Adds a new entry into the edit history. Creates a new changeset if there is not one already open.
	 * If behind in history, deletes all history entries in front.
	 */
	template<typename T, typename... Rs>
	void add(Rs&&... args)
	{
		if (not this->changesetOpen)
		{
			while (this->position < this->changesets.size())
			{
				this->changesets.erase(this->changesets.end() - 1);
			}
			if (this->changesets.empty())
			{
				this->changesets.emplace_back();
			}
			this->changesetOpen = true;
		}
		this->changesets.back().emplace_back(args...);
	}
	void commit()
	{
		this->changesetOpen = false;
		this->position += 1;
	}
private:
	std::vector<Changeset> changesets;
	std::size_t position = 0;
	bool changesetOpen = false;
};