CPlusPlus: CppEditor: refactor overview model

Introduce abstract model to be able to use clang
based version of it in follow up patches.
Fix warnings and modernize source code a little.
Move OverviewModel to CppTools.

Change-Id: Idcc9bf03cad047026a456bd01063597a1eb95147
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cpptools/abstractoverviewmodel.h

@@ -0,0 +1,100 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "cpptools_global.h"
+
+#include <utils/dropsupport.h>
+
+#include <QAbstractItemModel>
+#include <QSharedPointer>
+
+namespace CPlusPlus {
+class Document;
+class Symbol;
+}
+
+namespace CppTools {
+
+class CPPTOOLS_EXPORT AbstractOverviewModel : public QAbstractItemModel
+{
+    Q_OBJECT
+
+public:
+    enum Role {
+        FileNameRole = Qt::UserRole + 1,
+        LineNumberRole
+    };
+
+    AbstractOverviewModel(QObject *parent = nullptr) : QAbstractItemModel(parent) {}
+
+    virtual QSharedPointer<CPlusPlus::Document> document() const
+    {
+        return {};
+    }
+
+    virtual CPlusPlus::Symbol *symbolFromIndex(const QModelIndex &) const
+    {
+        return {};
+    }
+
+    virtual void rebuild(QSharedPointer<CPlusPlus::Document>) {}
+
+    Qt::ItemFlags flags(const QModelIndex &index) const override
+    {
+        if (!index.isValid())
+            return Qt::NoItemFlags;
+
+        return Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDragEnabled;
+    }
+
+    Qt::DropActions supportedDragActions() const override
+    {
+        return Qt::MoveAction;
+    }
+
+    QStringList mimeTypes() const override
+    {
+        return Utils::DropSupport::mimeTypesForFilePaths();
+    }
+
+    QMimeData *mimeData(const QModelIndexList &indexes) const override
+    {
+        auto mimeData = new Utils::DropMimeData;
+        foreach (const QModelIndex &index, indexes) {
+            const QVariant fileName = data(index, FileNameRole);
+            if (!fileName.canConvert<QString>())
+                continue;
+            const QVariant lineNumber = data(index, LineNumberRole);
+            if (!lineNumber.canConvert<unsigned>())
+                continue;
+            mimeData->addFile(fileName.toString(), static_cast<int>(lineNumber.value<unsigned>()));
+        }
+        return mimeData;
+    }
+};
+
+} // namespace CppTools