Support HTML5 <datalist> element

The datalist uses Chromium's autofill component to fetch and filter
predefined options in the list and autocomplete the field with the
selected option. Autofill component is added to build and bound to
WebEngine. All the unnecessary autofill features for datalist are
supposed to be disabled: payment/credit card support, password manager,
save profile data, store suggestions in database etc.

Custom popups for the dropdown are implemented for Widget and Quick.
Scrolling in dropdown is not implemented in this change.

Fixes: QTBUG-54433
Pick-to: 6.4
Change-Id: I155d02d6dbc9d88fbca4bc5f55b76c19d0ba7a9d
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

2 files changed, 331 insertions, 0 deletions

diff --git a/src/webenginewidgets/ui/autofillpopupwidget.cpp b/src/webenginewidgets/ui/autofillpopupwidget.cpp
new file mode 100644
index 000000000..579869d9e
--- /dev/null
+++ b/src/webenginewidgets/ui/autofillpopupwidget.cpp
@@ -0,0 +1,237 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine 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 "autofillpopupwidget_p.h"
+#include "qwebengineview.h"
+#include "qwebengineview_p.h"
+
+#include "autofill_popup_controller.h"
+
+#include <QApplication>
+#include <QBoxLayout>
+#include <QEvent>
+#include <QKeyEvent>
+#include <QListView>
+#include <QMouseEvent>
+
+namespace QtWebEngineWidgetUI {
+
+AutofillPopupWidget::AutofillPopupWidget(QtWebEngineCore::AutofillPopupController *controller,
+                                         QWebEngineView *parent)
+    : QFrame(parent, Qt::Popup), m_controller(controller), m_webEngineView(parent)
+{
+    setAttribute(Qt::WA_WindowPropagation);
+    setAttribute(Qt::WA_X11NetWmWindowTypeCombo);
+
+    // we need a vertical layout
+    QBoxLayout *layout = new QBoxLayout(QBoxLayout::TopToBottom, this);
+    layout->setSpacing(0);
+    layout->setContentsMargins(QMargins());
+
+    m_listView = new QListView(m_webEngineView);
+    m_listView->setModel(m_controller->model());
+    m_listView->setTextElideMode(Qt::ElideMiddle);
+
+    // Based on QComboBoxPrivateContainer::setItemView
+    m_listView->setParent(this);
+    m_listView->setAttribute(Qt::WA_MacShowFocusRect, false);
+    layout->insertWidget(0, m_listView);
+    m_listView->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
+
+    m_listView->installEventFilter(this);
+    // Necessary for filtering QEvent::MouseMove:
+    m_listView->viewport()->installEventFilter(this);
+
+    m_listView->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    // TODO: Implement vertical scrollbar. Chromium also has it.
+    m_listView->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    m_listView->setMouseTracking(true);
+
+    m_listView->setSelectionMode(QAbstractItemView::SingleSelection);
+    m_listView->setEditTriggers(QAbstractItemView::NoEditTriggers);
+
+    // Some styles (Mac) have a margin at the top and bottom of the popup.
+    layout->insertSpacing(0, 0);
+    layout->addSpacing(0);
+
+    connect(m_controller, &QtWebEngineCore::AutofillPopupController::currentIndexChanged,
+            m_listView, &QListView::setCurrentIndex);
+}
+
+AutofillPopupWidget::~AutofillPopupWidget() { }
+
+// Based on QComboBox::showPopup()
+void AutofillPopupWidget::showPopup(QPoint pos, int width, bool autoselectFirstSuggestion)
+{
+    QStyle *const style = m_webEngineView->style();
+    QStyleOptionComboBox opt;
+    opt.initFrom(m_webEngineView);
+
+    if (autoselectFirstSuggestion)
+        m_controller->selectFirstSuggestion();
+
+    QRect listRect(pos, QSize(width, 0));
+
+    // Calculate height
+    {
+        int listHeight = 0;
+        int rowCount = m_controller->model()->rowCount();
+        for (int i = 0; i < rowCount; ++i) {
+            QModelIndex idx = m_controller->model()->index(i, 0);
+            listHeight += m_listView->visualRect(idx).height();
+        }
+        if (rowCount > 1)
+            listHeight += (rowCount - 1) * m_listView->spacing() * 2;
+
+        listRect.setHeight(listRect.height() + listHeight);
+    }
+
+    // Calculate height margin
+    {
+        int heightMargin = m_listView->spacing() * 2;
+
+        // Add the frame of the popup
+        const QMargins pm = contentsMargins();
+        heightMargin += pm.top() + pm.bottom();
+
+        // Add the frame of the list view
+        const QMargins vm = m_listView->contentsMargins();
+        heightMargin += vm.top() + vm.bottom();
+        listRect.setHeight(listRect.height() + heightMargin);
+    }
+
+    // Add space for margin at top and bottom if the style wants it
+    int styleMargin = style->pixelMetric(QStyle::PM_MenuVMargin, &opt, this) * 2;
+    listRect.setHeight(listRect.height() + styleMargin);
+
+    // Takes account of the mimium/maximum size of the popup
+    layout()->activate();
+    listRect.setSize(listRect.size().expandedTo(minimumSize()).boundedTo(maximumSize()));
+
+    setGeometry(listRect);
+    QFrame::show();
+}
+
+bool AutofillPopupWidget::eventFilter(QObject *object, QEvent *event)
+{
+    switch (event->type()) {
+    case QEvent::MouseMove:
+        if (isVisible()) {
+            QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+            QModelIndex indexUnderMouse = m_listView->indexAt(mouseEvent->position().toPoint());
+            if (indexUnderMouse.isValid()
+                && indexUnderMouse.data(Qt::AccessibleDescriptionRole).toString()
+                        != QLatin1String("separator")) {
+                m_controller->selectSuggestion(indexUnderMouse.row());
+            }
+        }
+        return true;
+    case QEvent::MouseButtonRelease: {
+        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+        if (mouseEvent->button() == Qt::LeftButton) {
+            m_controller->acceptSuggestion();
+            return true;
+        }
+        break;
+    }
+    default:
+        break;
+    }
+
+    return QFrame::eventFilter(object, event);
+}
+
+void AutofillPopupWidget::keyPressEvent(QKeyEvent *event)
+{
+    // AutofillPopupControllerImpl::HandleKeyPressEvent()
+    // chrome/browser/ui/autofill/autofill_popup_controller_impl.cc
+    switch (event->key()) {
+    case Qt::Key_Up:
+        m_controller->selectPreviousSuggestion();
+        return;
+    case Qt::Key_Down:
+        m_controller->selectNextSuggestion();
+        return;
+    case Qt::Key_PageUp:
+        m_controller->selectFirstSuggestion();
+        return;
+    case Qt::Key_PageDown:
+        m_controller->selectLastSuggestion();
+        return;
+    case Qt::Key_Escape:
+        m_webEngineView->d_ptr->hideAutofillPopup();
+        return;
+    case Qt::Key_Enter:
+    case Qt::Key_Return:
+        m_controller->acceptSuggestion();
+        return;
+    case Qt::Key_Delete:
+        // Remove suggestion is not supported for datalist.
+        // Forward delete to view to be able to remove selected text.
+        break;
+    case Qt::Key_Tab:
+        m_controller->acceptSuggestion();
+        break;
+    default:
+        break;
+    }
+
+    QCoreApplication::sendEvent(m_webEngineView->focusWidget(), event);
+}
+
+void AutofillPopupWidget::keyReleaseEvent(QKeyEvent *event)
+{
+    // Do not forward release events of the overridden key presses.
+    switch (event->key()) {
+    case Qt::Key_Up:
+    case Qt::Key_Down:
+    case Qt::Key_PageUp:
+    case Qt::Key_PageDown:
+    case Qt::Key_Escape:
+    case Qt::Key_Enter:
+    case Qt::Key_Return:
+        return;
+    default:
+        break;
+    }
+
+    QCoreApplication::sendEvent(m_webEngineView->focusWidget(), event);
+}
+
+} // namespace QtWebEngineWidgetUI
diff --git a/src/webenginewidgets/ui/autofillpopupwidget_p.h b/src/webenginewidgets/ui/autofillpopupwidget_p.h
new file mode 100644
index 000000000..064c4f824
--- /dev/null
+++ b/src/webenginewidgets/ui/autofillpopupwidget_p.h
@@ -0,0 +1,94 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef AUTOFILLPOPUPWIDGET_P_H
+#define AUTOFILLPOPUPWIDGET_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QFrame>
+
+namespace QtWebEngineCore {
+class AutofillPopupController;
+}
+
+QT_BEGIN_NAMESPACE
+class QListView;
+class QWebEngineView;
+class QWebEngineViewPrivate;
+QT_END_NAMESPACE
+
+namespace QtWebEngineWidgetUI {
+
+// Based on QComboBoxPrivateContainer
+class AutofillPopupWidget : public QFrame
+{
+    Q_OBJECT
+public:
+    AutofillPopupWidget(QtWebEngineCore::AutofillPopupController *controller,
+                        QWebEngineView *parent);
+    ~AutofillPopupWidget();
+
+    void showPopup(QPoint pos, int width, bool autoselectFirstSuggestion);
+
+protected:
+    bool eventFilter(QObject *object, QEvent *event) override;
+    void keyPressEvent(QKeyEvent *event) override;
+    void keyReleaseEvent(QKeyEvent *event) override;
+
+private:
+    QtWebEngineCore::AutofillPopupController *m_controller;
+    QWebEngineView *m_webEngineView;
+    QListView *m_listView;
+
+    friend class QT_PREPEND_NAMESPACE(QWebEngineViewPrivate);
+};
+
+} // namespace QtWebEngineWidgetUI
+
+#endif // AUTOFILLPOPUPWIDGET_P_H