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74a4571f02
The undo stack was very difficult to understand as it grew by adding new undo commands to the front of the internal vector. This meant we had to keep updating indices as the stack grew and shrank. This patch makes the internal vector grow by appending instead.
107 lines
2.1 KiB
C++
107 lines
2.1 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibGUI/Command.h>
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#include <LibGUI/UndoStack.h>
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namespace GUI {
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UndoStack::UndoStack()
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{
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}
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UndoStack::~UndoStack()
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{
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}
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bool UndoStack::can_undo() const
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{
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return m_stack_index > 0;
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}
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bool UndoStack::can_redo() const
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{
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if (m_stack.is_empty())
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return false;
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return m_stack_index != m_stack.size() - 1;
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}
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void UndoStack::undo()
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{
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if (!can_undo())
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return;
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finalize_current_combo();
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auto& combo = m_stack[--m_stack_index];
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for (auto i = static_cast<ssize_t>(combo.commands.size()) - 1; i >= 0; i--)
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combo.commands[i].undo();
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}
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void UndoStack::redo()
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{
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if (!can_redo())
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return;
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auto& commands = m_stack[m_stack_index++].commands;
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for (auto& command : commands)
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command.redo();
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}
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void UndoStack::pop()
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{
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VERIFY(!m_stack.is_empty());
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m_stack.take_last();
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if (m_clean_index.has_value() && m_clean_index.value() > m_stack.size())
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m_clean_index = {};
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}
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void UndoStack::push(NonnullOwnPtr<Command>&& command)
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{
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if (m_stack.is_empty())
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m_stack.append(make<Combo>());
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// If the stack cursor is behind the top of the stack, nuke everything from here to the top.
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if (m_stack_index != m_stack.size() - 1) {
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while (m_stack.size() != m_stack_index) {
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pop();
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}
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finalize_current_combo();
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}
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m_stack.last().commands.append(move(command));
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}
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void UndoStack::finalize_current_combo()
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{
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if (m_stack.is_empty()) {
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m_stack.append(make<Combo>());
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return;
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}
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if (!m_stack.last().commands.is_empty()) {
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m_stack.append(make<Combo>());
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m_stack_index = m_stack.size() - 1;
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}
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}
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void UndoStack::set_current_unmodified()
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{
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m_clean_index = m_stack_index;
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}
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bool UndoStack::is_current_modified() const
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{
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return !(m_clean_index.has_value() && m_clean_index.value() == m_stack_index);
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}
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void UndoStack::clear()
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{
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m_stack.clear();
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m_stack_index = 0;
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m_clean_index.clear();
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}
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}
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