From 98b6aea234c952a17134015b5636751b21f8f3c9 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 25 Sep 2022 12:08:42 +0200
Subject: [PATCH] Ladybird: Add a ModelTranslator to translate a GUI::Model to
 a Qt model

This will be used to expose the DOMTreeModel from LibWebView :^)
---
 Ladybird/ModelTranslator.cpp | 84 ++++++++++++++++++++++++++++++++++++
 Ladybird/ModelTranslator.h   | 33 ++++++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 Ladybird/ModelTranslator.cpp
 create mode 100644 Ladybird/ModelTranslator.h

diff --git a/Ladybird/ModelTranslator.cpp b/Ladybird/ModelTranslator.cpp
new file mode 100644
index 0000000000..e342c788ee
--- /dev/null
+++ b/Ladybird/ModelTranslator.cpp
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#define AK_DONT_REPLACE_STD
+
+#include "ModelTranslator.h"
+#include "Utilities.h"
+#include <QIcon>
+
+namespace Ladybird {
+
+ModelTranslator::ModelTranslator(NonnullRefPtr<GUI::Model> model)
+    : m_model(move(model))
+{
+}
+
+ModelTranslator::~ModelTranslator() = default;
+
+int ModelTranslator::columnCount(QModelIndex const& parent) const
+{
+    return m_model->column_count(to_gui(parent));
+}
+
+int ModelTranslator::rowCount(QModelIndex const& parent) const
+{
+    return m_model->row_count(to_gui(parent));
+}
+
+static QVariant convert_variant(GUI::Variant const& value)
+{
+    if (value.is_string())
+        return qstring_from_akstring(value.as_string());
+    if (value.is_icon()) {
+        auto const& gui_icon = value.as_icon();
+        auto bitmap = gui_icon.bitmap_for_size(16);
+        VERIFY(bitmap);
+        auto qt_image = QImage(bitmap->scanline_u8(0), 16, 16, QImage::Format_ARGB32);
+        QIcon qt_icon;
+        qt_icon.addPixmap(QPixmap::fromImage(qt_image.convertToFormat(QImage::Format::Format_ARGB32_Premultiplied)));
+        return qt_icon;
+    }
+    return {};
+}
+
+QVariant ModelTranslator::data(QModelIndex const& index, int role) const
+{
+    switch (role) {
+    case Qt::DisplayRole:
+        return convert_variant(m_model->data(to_gui(index), GUI::ModelRole::Display));
+    case Qt::DecorationRole:
+        return convert_variant(m_model->data(to_gui(index), GUI::ModelRole::Icon));
+    default:
+        return {};
+    }
+}
+
+QModelIndex ModelTranslator::index(int row, int column, QModelIndex const& parent) const
+{
+    return to_qt(m_model->index(row, column, to_gui(parent)));
+}
+
+QModelIndex ModelTranslator::parent(QModelIndex const& index) const
+{
+    return to_qt(m_model->parent_index(to_gui(index)));
+}
+
+QModelIndex ModelTranslator::to_qt(GUI::ModelIndex const& index) const
+{
+    if (!index.is_valid())
+        return {};
+    return createIndex(index.row(), index.column(), index.internal_data());
+}
+
+GUI::ModelIndex ModelTranslator::to_gui(QModelIndex const& index) const
+{
+    if (!index.isValid())
+        return {};
+    return m_model->create_index_unsafe(index.row(), index.column(), index.internalPointer());
+}
+
+}
diff --git a/Ladybird/ModelTranslator.h b/Ladybird/ModelTranslator.h
new file mode 100644
index 0000000000..6890b1e2d0
--- /dev/null
+++ b/Ladybird/ModelTranslator.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibGUI/Model.h>
+#include <QAbstractItemModel>
+
+namespace Ladybird {
+
+class ModelTranslator final : public QAbstractItemModel {
+    Q_OBJECT
+public:
+    explicit ModelTranslator(NonnullRefPtr<GUI::Model>);
+    virtual ~ModelTranslator() override;
+
+    virtual int columnCount(QModelIndex const& parent) const override;
+    virtual int rowCount(QModelIndex const& parent) const override;
+    virtual QVariant data(QModelIndex const&, int role) const override;
+    virtual QModelIndex index(int row, int column, QModelIndex const& parent) const override;
+    virtual QModelIndex parent(QModelIndex const& index) const override;
+
+    QModelIndex to_qt(GUI::ModelIndex const&) const;
+    GUI::ModelIndex to_gui(QModelIndex const&) const;
+
+private:
+    RefPtr<GUI::Model> m_model;
+};
+
+}