Remove QGuiAction again and split QAction implementation up instead

Duplicating the number of classes is a high price to pay to be able to
have some QAction functionality behave differently, or be only available
in widgets applications.

Instead, declare the entire API in QtGui in QAction* classes, and
delegate the implementation of QtWidgets specific functionality to
the private. The creation of the private is then delegated to the
Q(Gui)ApplicationPrivate instance through a virtual factory function.

Change some public APIs that are primarily useful for specialized tools
such as Designer to operate on QObject* rather than QWidget*. APIs that
depend on QtWidgets types have been turned into inline template
functions, so that they are instantiated only at the caller side, where
we can expect the respective types to be fully defined. This way, we
only need to forward declare a few classes in the header, and don't
need to generate any additional code for e.g. language bindings.

Change-Id: Id0b27f9187652ec531a2e8b1b9837e82dc81625c
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 366 insertions, 0 deletions

diff --git a/src/gui/kernel/qactiongroup.cpp b/src/gui/kernel/qactiongroup.cpp
new file mode 100644
index 0000000000..6e2efdb74b
--- /dev/null
+++ b/src/gui/kernel/qactiongroup.cpp
@@ -0,0 +1,366 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui 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 "qactiongroup.h"
+
+#include "qaction.h"
+#include "qaction_p.h"
+#include "qactiongroup_p.h"
+#include "qevent.h"
+#include "qlist.h"
+
+QT_BEGIN_NAMESPACE
+
+QActionGroupPrivate::QActionGroupPrivate() :
+    enabled(1), visible(1)
+{
+}
+
+QActionGroupPrivate::~QActionGroupPrivate() = default;
+
+void QActionGroup::_q_actionChanged()
+{
+    Q_D(QActionGroup);
+    auto action = qobject_cast<QAction*>(sender());
+    Q_ASSERT_X(action != nullptr, "QActionGroup::_q_actionChanged", "internal error");
+    if (d->exclusionPolicy != QActionGroup::ExclusionPolicy::None) {
+        if (action->isChecked()) {
+            if (action != d->current) {
+                if (!d->current.isNull())
+                    d->current->setChecked(false);
+                d->current = action;
+            }
+        } else if (action == d->current) {
+            d->current = nullptr;
+        }
+    }
+}
+
+void QActionGroup::_q_actionTriggered()
+{
+    auto action = qobject_cast<QAction*>(sender());
+    Q_ASSERT_X(action != nullptr, "QActionGroup::_q_actionTriggered", "internal error");
+    emit triggered(action);
+}
+
+void QActionGroup::_q_actionHovered()
+{
+    auto action = qobject_cast<QAction*>(sender());
+    Q_ASSERT_X(action != nullptr, "QActionGroup::_q_actionHovered", "internal error");
+    emit hovered(action);
+}
+
+/*!
+    \class QActionGroup
+    \brief The QActionGroup class groups actions together.
+    \since 6.0
+
+    \inmodule QtGui
+
+    QActionGroup is a base class for classes grouping
+    classes inhheriting QAction objects together.
+
+    In some situations it is useful to group QAction objects together.
+    For example, if you have a \uicontrol{Left Align} action, a \uicontrol{Right
+    Align} action, a \uicontrol{Justify} action, and a \uicontrol{Center} action,
+    only one of these actions should be active at any one time. One
+    simple way of achieving this is to group the actions together in
+    an action group, inheriting QActionGroup.
+
+    \sa QAction
+*/
+
+/*!
+    \enum QActionGroup::ExclusionPolicy
+
+    This enum specifies the different policies that can be used to
+    control how the group performs exclusive checking on checkable actions.
+
+    \value None
+           The actions in the group can be checked independently of each other.
+
+    \value Exclusive
+           Exactly one action can be checked at any one time.
+           This is the default policy.
+
+    \value ExclusiveOptional
+           At most one action can be checked at any one time. The actions
+           can also be all unchecked.
+
+    \sa exclusionPolicy
+*/
+
+/*!
+    Constructs an action group for the \a parent object.
+
+    The action group is exclusive by default. Call setExclusive(false)
+    to make the action group non-exclusive. To make the group exclusive
+    but allow unchecking the active action call instead
+    setExclusionPolicy(QActionGroup::ExclusionPolicy::ExclusiveOptional)
+*/
+QActionGroup::QActionGroup(QObject* parent) :
+    QActionGroup(*new QActionGroupPrivate, parent)
+{
+}
+
+QActionGroup::QActionGroup(QActionGroupPrivate &dd, QObject *parent) :
+    QObject(dd, parent)
+{
+}
+
+/*!
+    Destroys the action group.
+*/
+QActionGroup::~QActionGroup() = default;
+
+/*!
+    \fn QAction *QActionGroup::addAction(QAction *action)
+
+    Adds the \a action to this group, and returns it.
+
+    Normally an action is added to a group by creating it with the
+    group as its parent, so this function is not usually used.
+
+    \sa QAction::setActionGroup()
+*/
+QAction *QActionGroup::addAction(QAction* a)
+{
+    Q_D(QActionGroup);
+    if (!d->actions.contains(a)) {
+        d->actions.append(a);
+        QObject::connect(a, &QAction::triggered, this, &QActionGroup::_q_actionTriggered);
+        QObject::connect(a, &QAction::changed, this, &QActionGroup::_q_actionChanged);
+        QObject::connect(a, &QAction::hovered, this, &QActionGroup::_q_actionHovered);
+    }
+    a->d_func()->setEnabled(d->enabled, true);
+    if (!a->d_func()->forceInvisible) {
+        a->setVisible(d->visible);
+        a->d_func()->forceInvisible = false;
+    }
+    if (a->isChecked())
+        d->current = a;
+    QActionGroup *oldGroup = a->d_func()->group;
+    if (oldGroup != this) {
+        if (oldGroup)
+            oldGroup->removeAction(a);
+        a->d_func()->group = this;
+        a->d_func()->sendDataChanged();
+    }
+    return a;
+}
+
+/*!
+    Creates and returns an action with \a text.  The newly created
+    action is a child of this action group.
+
+    Normally an action is added to a group by creating it with the
+    group as parent, so this function is not usually used.
+
+    \sa QAction::setActionGroup()
+*/
+QAction *QActionGroup::addAction(const QString &text)
+{
+    return new QAction(text, this);
+}
+
+/*!
+    Creates and returns an action with \a text and an \a icon. The
+    newly created action is a child of this action group.
+
+    Normally an action is added to a group by creating it with the
+    group as its parent, so this function is not usually used.
+
+    \sa QAction::setActionGroup()
+*/
+QAction *QActionGroup::addAction(const QIcon &icon, const QString &text)
+{
+    return new QAction(icon, text, this);
+}
+
+/*!
+  Removes the \a action from this group. The action will have no
+  parent as a result.
+
+  \sa QAction::setActionGroup()
+*/
+void QActionGroup::removeAction(QAction *action)
+{
+    Q_D(QActionGroup);
+    if (d->actions.removeAll(action)) {
+        if (action == d->current)
+            d->current = nullptr;
+        QObject::disconnect(action, &QAction::triggered, this, &QActionGroup::_q_actionTriggered);
+        QObject::disconnect(action, &QAction::changed, this, &QActionGroup::_q_actionChanged);
+        QObject::disconnect(action, &QAction::hovered, this, &QActionGroup::_q_actionHovered);
+        action->d_func()->group = nullptr;
+    }
+}
+
+/*!
+    Returns the list of this groups's actions. This may be empty.
+*/
+QList<QAction*> QActionGroup::actions() const
+{
+    Q_D(const QActionGroup);
+    return d->actions;
+}
+
+/*!
+    \brief Enable or disable the group exclusion checking
+
+    This is a convenience method that calls
+    setExclusionPolicy(ExclusionPolicy::Exclusive) when \a b is true,
+    else setExclusionPolicy(QActionGroup::ExclusionPolicy::None).
+
+    \sa QActionGroup::exclusionPolicy
+*/
+void QActionGroup::setExclusive(bool b)
+{
+    setExclusionPolicy(b ? QActionGroup::ExclusionPolicy::Exclusive
+                         : QActionGroup::ExclusionPolicy::None);
+}
+
+/*!
+    \brief Returns true if the group is exclusive
+
+    The group is exclusive if the ExclusionPolicy is either Exclusive
+    or ExclusionOptional.
+
+*/
+bool QActionGroup::isExclusive() const
+{
+    return exclusionPolicy() != QActionGroup::ExclusionPolicy::None;
+}
+
+/*!
+    \property QActionGroup::exclusionPolicy
+    \brief This property holds the group exclusive checking policy
+
+    If exclusionPolicy is set to Exclusive, only one checkable
+    action in the action group can ever be active at any time. If the user
+    chooses another checkable action in the group, the one they chose becomes
+    active and the one that was active becomes inactive. If exclusionPolicy is
+    set to ExclusionOptional the group is exclusive but the active checkable
+    action in the group can be unchecked leaving the group with no actions
+    checked.
+
+    \sa QAction::checkable
+*/
+void QActionGroup::setExclusionPolicy(QActionGroup::ExclusionPolicy policy)
+{
+    Q_D(QActionGroup);
+    d->exclusionPolicy = policy;
+}
+
+QActionGroup::ExclusionPolicy QActionGroup::exclusionPolicy() const
+{
+    Q_D(const QActionGroup);
+    return d->exclusionPolicy;
+}
+
+/*!
+    \fn void QActionGroup::setDisabled(bool b)
+
+    This is a convenience function for the \l enabled property, that
+    is useful for signals--slots connections. If \a b is true the
+    action group is disabled; otherwise it is enabled.
+*/
+
+/*!
+    \property QActionGroup::enabled
+    \brief whether the action group is enabled
+
+    Each action in the group will be enabled or disabled unless it
+    has been explicitly disabled.
+
+    \sa QAction::setEnabled()
+*/
+void QActionGroup::setEnabled(bool b)
+{
+    Q_D(QActionGroup);
+    d->enabled = b;
+    for (auto action : qAsConst(d->actions)) {
+        action->d_func()->setEnabled(b, true);
+    }
+}
+
+bool QActionGroup::isEnabled() const
+{
+    Q_D(const QActionGroup);
+    return d->enabled;
+}
+
+/*!
+  Returns the currently checked action in the group, or \nullptr if
+  none are checked.
+*/
+QAction *QActionGroup::checkedAction() const
+{
+    Q_D(const QActionGroup);
+    return d->current.data();
+}
+
+/*!
+    \property QActionGroup::visible
+    \brief whether the action group is visible
+
+    Each action in the action group will match the visible state of
+    this group unless it has been explicitly hidden.
+
+    \sa QAction::setEnabled()
+*/
+void QActionGroup::setVisible(bool b)
+{
+    Q_D(QActionGroup);
+    d->visible = b;
+    for (auto action : qAsConst(d->actions)) {
+        if (!action->d_func()->forceInvisible) {
+            action->setVisible(b);
+            action->d_func()->forceInvisible = false;
+        }
+    }
+}
+
+bool QActionGroup::isVisible() const
+{
+    Q_D(const QActionGroup);
+    return d->visible;
+}
+
+QT_END_NAMESPACE