Beautifier: Move formatting tools to TextEditor

Formatting is moved from Beautifier plugin to formattexteditor.h/.cpp.
Diff and Differ classes are extracted from DiffEditor to Utils
to prevent extra TextEditor dependencies.

This change will make possible to use formatCurrentFile
and similar functions not only from Beautifier code.

Change-Id: Ic5ca668afe88f4e9376d49e6bd3594807172b0dd
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/texteditor/formattexteditor.h

@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** 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 "texteditor_global.h"
+
+#include "command.h"
+
+#include <QPlainTextEdit>
+#include <QPointer>
+
+namespace TextEditor {
+
+class TextEditorWidget;
+
+class TEXTEDITOR_EXPORT FormatTask
+{
+public:
+    FormatTask(QPlainTextEdit *_editor, const QString &_filePath, const QString &_sourceData,
+               const Command &_command, int _startPos = -1, int _endPos = 0) :
+        editor(_editor),
+        filePath(_filePath),
+        sourceData(_sourceData),
+        command(_command),
+        startPos(_startPos),
+        endPos(_endPos) {}
+
+    QPointer<QPlainTextEdit> editor;
+    QString filePath;
+    QString sourceData;
+    TextEditor::Command command;
+    int startPos = -1;
+    int endPos = 0;
+    QString formattedData;
+    QString error;
+};
+
+TEXTEDITOR_EXPORT void formatCurrentFile(const TextEditor::Command &command, int startPos = -1, int endPos = 0);
+TEXTEDITOR_EXPORT void formatEditor(TextEditorWidget *editor, const TextEditor::Command &command,
+                  int startPos = -1, int endPos = 0);
+TEXTEDITOR_EXPORT void formatEditorAsync(TextEditorWidget *editor, const TextEditor::Command &command,
+                       int startPos = -1, int endPos = 0);
+
+} // namespace TextEditor