Move undo framework out of Qt Widgets

- Moves QUndo* classes (except QUndoView) from src/widgets/utils to src/gui/utils
- Moves related auto tests from widgets to gui
- Replaces QUndoAction with lambdas that do text prefixing

[ChangeLog][Undo Framework] QUndo* classes (except QUndoView) were moved from Qt
Widgets to Qt GUI.

Done-with: volker.hilsheimer@qt.io
Fixes: QTBUG-40040
Change-Id: I3bd8d4d32c64f8dee548f62159a1df2126da89d8
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 515 insertions, 0 deletions

diff --git a/src/gui/util/qundogroup.cpp b/src/gui/util/qundogroup.cpp
new file mode 100644
index 0000000000..2f4c81b046
--- /dev/null
+++ b/src/gui/util/qundogroup.cpp
@@ -0,0 +1,515 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWidgets module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qundogroup.h"
+#include "qundostack.h"
+#include "qundostack_p.h"
+
+QT_BEGIN_NAMESPACE
+
+class QUndoGroupPrivate : public QObjectPrivate
+{
+    Q_DECLARE_PUBLIC(QUndoGroup)
+public:
+    QUndoGroupPrivate() : active(nullptr) {}
+
+    QUndoStack *active;
+    QList<QUndoStack*> stack_list;
+};
+
+/*!
+    \class QUndoGroup
+    \brief The QUndoGroup class is a group of QUndoStack objects.
+    \since 4.2
+    \inmodule QtWidgets
+
+    For an overview of the Qt's undo framework, see the
+    \l{qundo.html}{overview}.
+
+    An application often has multiple undo stacks, one for each opened document. At the
+    same time, an application usually has one undo action and one redo action, which
+    triggers undo or redo in the active document.
+
+    QUndoGroup is a group of QUndoStack objects, one of which may be active. It has
+    an undo() and redo() slot, which calls QUndoStack::undo() and QUndoStack::redo()
+    for the active stack. It also has the functions createUndoAction() and createRedoAction().
+    The actions returned by these functions behave in the same way as those returned by
+    QUndoStack::createUndoAction() and QUndoStack::createRedoAction() of the active
+    stack.
+
+    Stacks are added to a group with addStack() and removed with removeStack(). A stack
+    is implicitly added to a group when it is created with the group as its parent
+    QObject.
+
+    It is the programmer's responsibility to specify which stack is active by
+    calling QUndoStack::setActive(), usually when the associated document window receives focus.
+    The active stack may also be set with setActiveStack(), and is returned by activeStack().
+
+    When a stack is added to a group using addStack(), the group does not take ownership
+    of the stack. This means the stack has to be deleted separately from the group. When
+    a stack is deleted, it is automatically removed from a group. A stack may belong to
+    only one group. Adding it to another group will cause it to be removed from the previous
+    group.
+
+    A QUndoGroup is also useful in conjunction with QUndoView. If a QUndoView is
+    set to watch a group using QUndoView::setGroup(), it will update itself to display
+    the active stack.
+*/
+
+/*!
+    Creates an empty QUndoGroup object with parent \a parent.
+
+    \sa addStack()
+*/
+
+QUndoGroup::QUndoGroup(QObject *parent)
+    : QObject(*new QUndoGroupPrivate(), parent)
+{
+}
+
+/*!
+    Destroys the QUndoGroup.
+*/
+QUndoGroup::~QUndoGroup()
+{
+    // Ensure all QUndoStacks no longer refer to this group.
+    Q_D(QUndoGroup);
+    QList<QUndoStack *>::iterator it = d->stack_list.begin();
+    QList<QUndoStack *>::iterator end = d->stack_list.end();
+    while (it != end) {
+        (*it)->d_func()->group = nullptr;
+        ++it;
+    }
+}
+
+/*!
+    Adds \a stack to this group. The group does not take ownership of the stack. Another
+    way of adding a stack to a group is by specifying the group as the stack's parent
+    QObject in QUndoStack::QUndoStack(). In this case, the stack is deleted when the
+    group is deleted, in the usual manner of QObjects.
+
+    \sa removeStack(), stacks(), QUndoStack::QUndoStack()
+*/
+
+void QUndoGroup::addStack(QUndoStack *stack)
+{
+    Q_D(QUndoGroup);
+
+    if (d->stack_list.contains(stack))
+        return;
+    d->stack_list.append(stack);
+
+    if (QUndoGroup *other = stack->d_func()->group)
+        other->removeStack(stack);
+    stack->d_func()->group = this;
+}
+
+/*!
+    Removes \a stack from this group. If the stack was the active stack in the group,
+    the active stack becomes 0.
+
+    \sa addStack(), stacks(), QUndoStack::~QUndoStack()
+*/
+
+void QUndoGroup::removeStack(QUndoStack *stack)
+{
+    Q_D(QUndoGroup);
+
+    if (d->stack_list.removeAll(stack) == 0)
+        return;
+    if (stack == d->active)
+        setActiveStack(nullptr);
+    stack->d_func()->group = nullptr;
+}
+
+/*!
+    Returns a list of stacks in this group.
+
+    \sa addStack(), removeStack()
+*/
+
+QList<QUndoStack*> QUndoGroup::stacks() const
+{
+    Q_D(const QUndoGroup);
+    return d->stack_list;
+}
+
+/*!
+    Sets the active stack of this group to \a stack.
+
+    If the stack is not a member of this group, this function does nothing.
+
+    Synonymous with calling QUndoStack::setActive() on \a stack.
+
+    The actions returned by createUndoAction() and createRedoAction() will now behave
+    in the same way as those returned by \a stack's QUndoStack::createUndoAction()
+    and QUndoStack::createRedoAction().
+
+    \sa QUndoStack::setActive(), activeStack()
+*/
+
+void QUndoGroup::setActiveStack(QUndoStack *stack)
+{
+    Q_D(QUndoGroup);
+    if (d->active == stack)
+        return;
+
+    if (d->active != nullptr) {
+        disconnect(d->active, SIGNAL(canUndoChanged(bool)),
+                    this, SIGNAL(canUndoChanged(bool)));
+        disconnect(d->active, SIGNAL(undoTextChanged(QString)),
+                    this, SIGNAL(undoTextChanged(QString)));
+        disconnect(d->active, SIGNAL(canRedoChanged(bool)),
+                    this, SIGNAL(canRedoChanged(bool)));
+        disconnect(d->active, SIGNAL(redoTextChanged(QString)),
+                    this, SIGNAL(redoTextChanged(QString)));
+        disconnect(d->active, SIGNAL(indexChanged(int)),
+                    this, SIGNAL(indexChanged(int)));
+        disconnect(d->active, SIGNAL(cleanChanged(bool)),
+                    this, SIGNAL(cleanChanged(bool)));
+    }
+
+    d->active = stack;
+
+    if (d->active == nullptr) {
+        emit canUndoChanged(false);
+        emit undoTextChanged(QString());
+        emit canRedoChanged(false);
+        emit redoTextChanged(QString());
+        emit cleanChanged(true);
+        emit indexChanged(0);
+    } else {
+        connect(d->active, SIGNAL(canUndoChanged(bool)),
+                this, SIGNAL(canUndoChanged(bool)));
+        connect(d->active, SIGNAL(undoTextChanged(QString)),
+                this, SIGNAL(undoTextChanged(QString)));
+        connect(d->active, SIGNAL(canRedoChanged(bool)),
+                this, SIGNAL(canRedoChanged(bool)));
+        connect(d->active, SIGNAL(redoTextChanged(QString)),
+                this, SIGNAL(redoTextChanged(QString)));
+        connect(d->active, SIGNAL(indexChanged(int)),
+                this, SIGNAL(indexChanged(int)));
+        connect(d->active, SIGNAL(cleanChanged(bool)),
+                this, SIGNAL(cleanChanged(bool)));
+        emit canUndoChanged(d->active->canUndo());
+        emit undoTextChanged(d->active->undoText());
+        emit canRedoChanged(d->active->canRedo());
+        emit redoTextChanged(d->active->redoText());
+        emit cleanChanged(d->active->isClean());
+        emit indexChanged(d->active->index());
+    }
+
+    emit activeStackChanged(d->active);
+}
+
+/*!
+    Returns the active stack of this group.
+
+    If none of the stacks are active, or if the group is empty, this function
+    returns \nullptr.
+
+    \sa setActiveStack(), QUndoStack::setActive()
+*/
+
+QUndoStack *QUndoGroup::activeStack() const
+{
+    Q_D(const QUndoGroup);
+    return d->active;
+}
+
+#ifndef QT_NO_ACTION
+
+/*!
+    Creates an undo QAction object with parent \a parent.
+
+    Triggering this action will cause a call to QUndoStack::undo() on the active stack.
+    The text of this action will always be the text of the command which will be undone
+    in the next call to undo(), prefixed by \a prefix. If there is no command available
+    for undo, if the group is empty or if none of the stacks are active, this action will
+    be disabled.
+
+    If \a prefix is empty, the default template "Undo %1" is used instead of prefix.
+    Before Qt 4.8, the prefix "Undo" was used by default.
+
+    \sa createRedoAction(), canUndo(), QUndoCommand::text()
+*/
+
+QAction *QUndoGroup::createUndoAction(QObject *parent, const QString &prefix) const
+{
+    QAction *action = new QAction(parent);
+    action->setEnabled(canUndo());
+
+    QString effectivePrefix = prefix;
+    QString defaultText;
+    if (prefix.isEmpty()) {
+        effectivePrefix = tr("Undo %1");
+        defaultText = tr("Undo", "Default text for undo action");
+    }
+
+    QUndoStackPrivate::setPrefixedText(action, effectivePrefix, defaultText, undoText());
+
+    connect(this, &QUndoGroup::canUndoChanged, action, &QAction::setEnabled);
+    connect(this, &QUndoGroup::undoTextChanged, action, [=](const QString &text) {
+        QUndoStackPrivate::setPrefixedText(action, effectivePrefix, defaultText, text);
+    });
+    connect(action, &QAction::triggered, this, &QUndoGroup::undo);
+
+    return action;
+}
+
+/*!
+    Creates an redo QAction object with parent \a parent.
+
+    Triggering this action will cause a call to QUndoStack::redo() on the active stack.
+    The text of this action will always be the text of the command which will be redone
+    in the next call to redo(), prefixed by \a prefix. If there is no command available
+    for redo, if the group is empty or if none of the stacks are active, this action will
+    be disabled.
+
+    If \a prefix is empty, the default template "Redo %1" is used instead of prefix.
+    Before Qt 4.8, the prefix "Redo" was used by default.
+
+    \sa createUndoAction(), canRedo(), QUndoCommand::text()
+*/
+
+QAction *QUndoGroup::createRedoAction(QObject *parent, const QString &prefix) const
+{
+    QAction *action = new QAction(parent);
+    action->setEnabled(canRedo());
+
+    QString effectivePrefix = prefix;
+    QString defaultText;
+    if (prefix.isEmpty()) {
+        effectivePrefix = tr("Redo %1");
+        defaultText = tr("Redo", "Default text for redo action");
+    }
+
+    QUndoStackPrivate::setPrefixedText(action, effectivePrefix, defaultText, redoText());
+
+    connect(this, &QUndoGroup::canRedoChanged, action, &QAction::setEnabled);
+    connect(this, &QUndoGroup::redoTextChanged, action, [=](const QString &text) {
+        QUndoStackPrivate::setPrefixedText(action, effectivePrefix, defaultText, text);
+    });
+    connect(action, &QAction::triggered, this, &QUndoGroup::redo);
+    return action;
+}
+
+#endif // QT_NO_ACTION
+
+/*!
+    Calls QUndoStack::undo() on the active stack.
+
+    If none of the stacks are active, or if the group is empty, this function
+    does nothing.
+
+    \sa redo(), canUndo(), setActiveStack()
+*/
+
+void QUndoGroup::undo()
+{
+    Q_D(QUndoGroup);
+    if (d->active != nullptr)
+        d->active->undo();
+}
+
+/*!
+    Calls QUndoStack::redo() on the active stack.
+
+    If none of the stacks are active, or if the group is empty, this function
+    does nothing.
+
+    \sa undo(), canRedo(), setActiveStack()
+*/
+
+
+void QUndoGroup::redo()
+{
+    Q_D(QUndoGroup);
+    if (d->active != nullptr)
+        d->active->redo();
+}
+
+/*!
+    Returns the value of the active stack's QUndoStack::canUndo().
+
+    If none of the stacks are active, or if the group is empty, this function
+    returns \c false.
+
+    \sa canRedo(), setActiveStack()
+*/
+
+bool QUndoGroup::canUndo() const
+{
+    Q_D(const QUndoGroup);
+    return d->active != nullptr && d->active->canUndo();
+}
+
+/*!
+    Returns the value of the active stack's QUndoStack::canRedo().
+
+    If none of the stacks are active, or if the group is empty, this function
+    returns \c false.
+
+    \sa canUndo(), setActiveStack()
+*/
+
+bool QUndoGroup::canRedo() const
+{
+    Q_D(const QUndoGroup);
+    return d->active != nullptr && d->active->canRedo();
+}
+
+/*!
+    Returns the value of the active stack's QUndoStack::undoText().
+
+    If none of the stacks are active, or if the group is empty, this function
+    returns an empty string.
+
+    \sa redoText(), setActiveStack()
+*/
+
+QString QUndoGroup::undoText() const
+{
+    Q_D(const QUndoGroup);
+    return d->active == nullptr ? QString() : d->active->undoText();
+}
+
+/*!
+    Returns the value of the active stack's QUndoStack::redoText().
+
+    If none of the stacks are active, or if the group is empty, this function
+    returns an empty string.
+
+    \sa undoText(), setActiveStack()
+*/
+
+QString QUndoGroup::redoText() const
+{
+    Q_D(const QUndoGroup);
+    return d->active == nullptr ? QString() : d->active->redoText();
+}
+
+/*!
+    Returns the value of the active stack's QUndoStack::isClean().
+
+    If none of the stacks are active, or if the group is empty, this function
+    returns \c true.
+
+    \sa setActiveStack()
+*/
+
+bool QUndoGroup::isClean() const
+{
+    Q_D(const QUndoGroup);
+    return d->active == nullptr || d->active->isClean();
+}
+
+/*! \fn void QUndoGroup::activeStackChanged(QUndoStack *stack)
+
+    This signal is emitted whenever the active stack of the group changes. This can happen
+    when setActiveStack() or QUndoStack::setActive() is called, or when the active stack
+    is removed form the group. \a stack is the new active stack. If no stack is active,
+    \a stack is 0.
+
+    \sa setActiveStack(), QUndoStack::setActive()
+*/
+
+/*! \fn void QUndoGroup::indexChanged(int idx)
+
+    This signal is emitted whenever the active stack emits QUndoStack::indexChanged()
+    or the active stack changes.
+
+    \a idx is the new current index, or 0 if the active stack is 0.
+
+    \sa QUndoStack::indexChanged(), setActiveStack()
+*/
+
+/*! \fn void QUndoGroup::cleanChanged(bool clean)
+
+    This signal is emitted whenever the active stack emits QUndoStack::cleanChanged()
+    or the active stack changes.
+
+    \a clean is the new state, or true if the active stack is 0.
+
+    \sa QUndoStack::cleanChanged(), setActiveStack()
+*/
+
+/*! \fn void QUndoGroup::canUndoChanged(bool canUndo)
+
+    This signal is emitted whenever the active stack emits QUndoStack::canUndoChanged()
+    or the active stack changes.
+
+    \a canUndo is the new state, or false if the active stack is 0.
+
+    \sa QUndoStack::canUndoChanged(), setActiveStack()
+*/
+
+/*! \fn void QUndoGroup::canRedoChanged(bool canRedo)
+
+    This signal is emitted whenever the active stack emits QUndoStack::canRedoChanged()
+    or the active stack changes.
+
+    \a canRedo is the new state, or false if the active stack is 0.
+
+    \sa QUndoStack::canRedoChanged(), setActiveStack()
+*/
+
+/*! \fn void QUndoGroup::undoTextChanged(const QString &undoText)
+
+    This signal is emitted whenever the active stack emits QUndoStack::undoTextChanged()
+    or the active stack changes.
+
+    \a undoText is the new state, or an empty string if the active stack is 0.
+
+    \sa QUndoStack::undoTextChanged(), setActiveStack()
+*/
+
+/*! \fn void QUndoGroup::redoTextChanged(const QString &redoText)
+
+    This signal is emitted whenever the active stack emits QUndoStack::redoTextChanged()
+    or the active stack changes.
+
+    \a redoText is the new state, or an empty string if the active stack is 0.
+
+    \sa QUndoStack::redoTextChanged(), setActiveStack()
+*/
+
+QT_END_NAMESPACE
+
+#include "moc_qundogroup.cpp"