ladybird/Libraries/LibGUI/UndoStack.h

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <AK/NonnullOwnPtrVector.h>
#include <LibGUI/Forward.h>

namespace GUI {

class UndoStack {
public:
    UndoStack();
    ~UndoStack();

    void push(NonnullOwnPtr<Command>&&);

    bool can_undo() const { return m_stack_index < m_stack.size() && !m_stack.is_empty(); }
    bool can_redo() const { return m_stack_index > 0 && m_stack[m_stack_index - 1].m_undo_vector.size() > 0 && !m_stack.is_empty(); }

    void undo();
    void redo();

    void finalize_current_combo();

private:
    struct UndoCommandsContainer {
        NonnullOwnPtrVector<Command> m_undo_vector;
    };

    NonnullOwnPtrVector<UndoCommandsContainer> m_stack;
    size_t m_stack_index { 0 };
    size_t m_last_updated_undo_vector_size { 0 };
};

}