qundostack.cpp

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#include <QtCore/qdebug.h>
#include "qundostack.h"
#include "qundogroup.h"
#include "qundostack_p.h"

#ifndef QT_NO_UNDOCOMMAND

QT_BEGIN_NAMESPACE

QUndoCommand::QUndoCommand(const QString &text, QUndoCommand *parent)
{
    d = new QUndoCommandPrivate;
    if (parent != 0)
        parent->d->child_list.append(this);
    setText(text);
}

QUndoCommand::QUndoCommand(QUndoCommand *parent)
{
    d = new QUndoCommandPrivate;
    if (parent != 0)
        parent->d->child_list.append(this);
}

QUndoCommand::~QUndoCommand()
{
    qDeleteAll(d->child_list);
    delete d;
}

int QUndoCommand::id() const
{
    return -1;
}

bool QUndoCommand::mergeWith(const QUndoCommand *command)
{
    Q_UNUSED(command);
    return false;
}

void QUndoCommand::redo()
{
    for (int i = 0; i < d->child_list.size(); ++i)
        d->child_list.at(i)->redo();
}

void QUndoCommand::undo()
{
    for (int i = d->child_list.size() - 1; i >= 0; --i)
        d->child_list.at(i)->undo();
}

QString QUndoCommand::text() const
{
    return d->text;
}

QString QUndoCommand::actionText() const
{
    return d->actionText;
}

void QUndoCommand::setText(const QString &text)
{
    int cdpos = text.indexOf(QLatin1Char('\n'));
    if (cdpos > 0) {
        d->text = text.left(cdpos);
        d->actionText = text.mid(cdpos + 1);
    } else {
        d->text = text;
        d->actionText = text;
    }
}

int QUndoCommand::childCount() const
{
    return d->child_list.count();
}

const QUndoCommand *QUndoCommand::child(int index) const
{
    if (index < 0 || index >= d->child_list.count())
        return 0;
    return d->child_list.at(index);
}

#endif // QT_NO_UNDOCOMMAND

#ifndef QT_NO_UNDOSTACK

#ifndef QT_NO_ACTION

QUndoAction::QUndoAction(const QString &prefix, QObject *parent)
    : QAction(parent)
{
    m_prefix = prefix;
}

void QUndoAction::setPrefixedText(const QString &text)
{
    if (m_defaultText.isEmpty()) {
        QString s = m_prefix;
        if (!m_prefix.isEmpty() && !text.isEmpty())
            s.append(QLatin1Char(' '));
        s.append(text);
        setText(s);
    } else {
        if (text.isEmpty())
            setText(m_defaultText);
        else
            setText(m_prefix.arg(text));
    }
}

void QUndoAction::setTextFormat(const QString &textFormat, const QString &defaultText)
{
    m_prefix = textFormat;
    m_defaultText = defaultText;
}

#endif // QT_NO_ACTION

void QUndoStackPrivate::setIndex(int idx, bool clean)
{
    Q_Q(QUndoStack);

    bool was_clean = index == clean_index;

    if (idx != index) {
        index = idx;
        emit q->indexChanged(index);
        emit q->canUndoChanged(q->canUndo());
        emit q->undoTextChanged(q->undoText());
        emit q->canRedoChanged(q->canRedo());
        emit q->redoTextChanged(q->redoText());
    }

    if (clean)
        clean_index = index;

    bool is_clean = index == clean_index;
    if (is_clean != was_clean)
        emit q->cleanChanged(is_clean);
}

bool QUndoStackPrivate::checkUndoLimit()
{
    if (undo_limit <= 0 || !macro_stack.isEmpty() || undo_limit >= command_list.count())
        return false;

    int del_count = command_list.count() - undo_limit;

    for (int i = 0; i < del_count; ++i)
        delete command_list.takeFirst();

    index -= del_count;
    if (clean_index != -1) {
        if (clean_index < del_count)
            clean_index = -1; // we've deleted the clean command
        else
            clean_index -= del_count;
    }

    return true;
}

QUndoStack::QUndoStack(QObject *parent)
    : QObject(*(new QUndoStackPrivate), parent)
{
#ifndef QT_NO_UNDOGROUP
    if (QUndoGroup *group = qobject_cast<QUndoGroup*>(parent))
        group->addStack(this);
#endif
}

QUndoStack::~QUndoStack()
{
#ifndef QT_NO_UNDOGROUP
    Q_D(QUndoStack);
    if (d->group != 0)
        d->group->removeStack(this);
#endif
    clear();
}

void QUndoStack::clear()
{
    Q_D(QUndoStack);

    if (d->command_list.isEmpty())
        return;

    bool was_clean = isClean();

    d->macro_stack.clear();
    qDeleteAll(d->command_list);
    d->command_list.clear();

    d->index = 0;
    d->clean_index = 0;

    emit indexChanged(0);
    emit canUndoChanged(false);
    emit undoTextChanged(QString());
    emit canRedoChanged(false);
    emit redoTextChanged(QString());

    if (!was_clean)
        emit cleanChanged(true);
}

void QUndoStack::push(QUndoCommand *cmd)
{
    Q_D(QUndoStack);
    cmd->redo();

    bool macro = !d->macro_stack.isEmpty();

    QUndoCommand *cur = 0;
    if (macro) {
        QUndoCommand *macro_cmd = d->macro_stack.last();
        if (!macro_cmd->d->child_list.isEmpty())
            cur = macro_cmd->d->child_list.last();
    } else {
        if (d->index > 0)
            cur = d->command_list.at(d->index - 1);
        while (d->index < d->command_list.size())
            delete d->command_list.takeLast();
        if (d->clean_index > d->index)
            d->clean_index = -1; // we've deleted the clean state
    }

    bool try_merge = cur != 0
                        && cur->id() != -1
                        && cur->id() == cmd->id()
                        && (macro || d->index != d->clean_index);

    if (try_merge && cur->mergeWith(cmd)) {
        delete cmd;
        if (!macro) {
            emit indexChanged(d->index);
            emit canUndoChanged(canUndo());
            emit undoTextChanged(undoText());
            emit canRedoChanged(canRedo());
            emit redoTextChanged(redoText());
        }
    } else {
        if (macro) {
            d->macro_stack.last()->d->child_list.append(cmd);
        } else {
            d->command_list.append(cmd);
            d->checkUndoLimit();
            d->setIndex(d->index + 1, false);
        }
    }
}

void QUndoStack::setClean()
{
    Q_D(QUndoStack);
    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::setClean(): cannot set clean in the middle of a macro");
        return;
    }

    d->setIndex(d->index, true);
}

bool QUndoStack::isClean() const
{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return false;
    return d->clean_index == d->index;
}

int QUndoStack::cleanIndex() const
{
    Q_D(const QUndoStack);
    return d->clean_index;
}

void QUndoStack::undo()
{
    Q_D(QUndoStack);
    if (d->index == 0)
        return;

    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::undo(): cannot undo in the middle of a macro");
        return;
    }

    int idx = d->index - 1;
    d->command_list.at(idx)->undo();
    d->setIndex(idx, false);
}

void QUndoStack::redo()
{
    Q_D(QUndoStack);
    if (d->index == d->command_list.size())
        return;

    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::redo(): cannot redo in the middle of a macro");
        return;
    }

    d->command_list.at(d->index)->redo();
    d->setIndex(d->index + 1, false);
}

int QUndoStack::count() const
{
    Q_D(const QUndoStack);
    return d->command_list.size();
}

int QUndoStack::index() const
{
    Q_D(const QUndoStack);
    return d->index;
}

void QUndoStack::setIndex(int idx)
{
    Q_D(QUndoStack);
    if (!d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::setIndex(): cannot set index in the middle of a macro");
        return;
    }

    if (idx < 0)
        idx = 0;
    else if (idx > d->command_list.size())
        idx = d->command_list.size();

    int i = d->index;
    while (i < idx)
        d->command_list.at(i++)->redo();
    while (i > idx)
        d->command_list.at(--i)->undo();

    d->setIndex(idx, false);
}

bool QUndoStack::canUndo() const
{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return false;
    return d->index > 0;
}

bool QUndoStack::canRedo() const
{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return false;
    return d->index < d->command_list.size();
}

QString QUndoStack::undoText() const
{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return QString();
    if (d->index > 0)
        return d->command_list.at(d->index - 1)->actionText();
    return QString();
}

QString QUndoStack::redoText() const
{
    Q_D(const QUndoStack);
    if (!d->macro_stack.isEmpty())
        return QString();
    if (d->index < d->command_list.size())
        return d->command_list.at(d->index)->actionText();
    return QString();
}

#ifndef QT_NO_ACTION

QAction *QUndoStack::createUndoAction(QObject *parent, const QString &prefix) const
{
    QUndoAction *result = new QUndoAction(prefix, parent);
    if (prefix.isEmpty())
        result->setTextFormat(tr("Undo %1"), tr("Undo", "Default text for undo action"));

    result->setEnabled(canUndo());
    result->setPrefixedText(undoText());
    connect(this, SIGNAL(canUndoChanged(bool)),
            result, SLOT(setEnabled(bool)));
    connect(this, SIGNAL(undoTextChanged(QString)),
            result, SLOT(setPrefixedText(QString)));
    connect(result, SIGNAL(triggered()), this, SLOT(undo()));
    return result;
}

QAction *QUndoStack::createRedoAction(QObject *parent, const QString &prefix) const
{
    QUndoAction *result = new QUndoAction(prefix, parent);
    if (prefix.isEmpty())
        result->setTextFormat(tr("Redo %1"), tr("Redo", "Default text for redo action"));

    result->setEnabled(canRedo());
    result->setPrefixedText(redoText());
    connect(this, SIGNAL(canRedoChanged(bool)),
            result, SLOT(setEnabled(bool)));
    connect(this, SIGNAL(redoTextChanged(QString)),
            result, SLOT(setPrefixedText(QString)));
    connect(result, SIGNAL(triggered()), this, SLOT(redo()));
    return result;
}

#endif // QT_NO_ACTION

void QUndoStack::beginMacro(const QString &text)
{
    Q_D(QUndoStack);
    QUndoCommand *cmd = new QUndoCommand();
    cmd->setText(text);

    if (d->macro_stack.isEmpty()) {
        while (d->index < d->command_list.size())
            delete d->command_list.takeLast();
        if (d->clean_index > d->index)
            d->clean_index = -1; // we've deleted the clean state
        d->command_list.append(cmd);
    } else {
        d->macro_stack.last()->d->child_list.append(cmd);
    }
    d->macro_stack.append(cmd);

    if (d->macro_stack.count() == 1) {
        emit canUndoChanged(false);
        emit undoTextChanged(QString());
        emit canRedoChanged(false);
        emit redoTextChanged(QString());
    }
}

void QUndoStack::endMacro()
{
    Q_D(QUndoStack);
    if (d->macro_stack.isEmpty()) {
        qWarning("QUndoStack::endMacro(): no matching beginMacro()");
        return;
    }

    d->macro_stack.removeLast();

    if (d->macro_stack.isEmpty()) {
        d->checkUndoLimit();
        d->setIndex(d->index + 1, false);
    }
}

const QUndoCommand *QUndoStack::command(int index) const
{
    Q_D(const QUndoStack);

    if (index < 0 || index >= d->command_list.count())
        return 0;
    return d->command_list.at(index);
}

QString QUndoStack::text(int idx) const
{
    Q_D(const QUndoStack);

    if (idx < 0 || idx >= d->command_list.size())
        return QString();
    return d->command_list.at(idx)->text();
}

void QUndoStack::setUndoLimit(int limit)
{
    Q_D(QUndoStack);

    if (!d->command_list.isEmpty()) {
        qWarning("QUndoStack::setUndoLimit(): an undo limit can only be set when the stack is empty");
        return;
    }

    if (limit == d->undo_limit)
        return;
    d->undo_limit = limit;
    d->checkUndoLimit();
}

int QUndoStack::undoLimit() const
{
    Q_D(const QUndoStack);

    return d->undo_limit;
}

void QUndoStack::setActive(bool active)
{
#ifdef QT_NO_UNDOGROUP
    Q_UNUSED(active);
#else
    Q_D(QUndoStack);

    if (d->group != 0) {
        if (active)
            d->group->setActiveStack(this);
        else if (d->group->activeStack() == this)
            d->group->setActiveStack(0);
    }
#endif
}

bool QUndoStack::isActive() const
{
#ifdef QT_NO_UNDOGROUP
    return true;
#else
    Q_D(const QUndoStack);
    return d->group == 0 || d->group->activeStack() == this;
#endif
}

QT_END_NAMESPACE

#endif // QT_NO_UNDOSTACK