LanguageClient: add lsp based auto formatter

Change-Id: I2a7347961b4633868aa3b033c351a1e709c3597e
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/languageclient/languageclientformatter.h

@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 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 "client.h"
+
+#include <texteditor/formatter.h>
+
+namespace TextEditor { class TextDocument; }
+namespace LanguageClient {
+
+class LanguageClientFormatter : public TextEditor::Formatter
+{
+public:
+    LanguageClientFormatter(TextEditor::TextDocument *document, Client *client);
+    ~LanguageClientFormatter() override;
+
+    QFutureWatcher<Utils::Text::Replacements> *format(
+        const QTextCursor &cursor, const TextEditor::TabSettings &tabSettings) override;
+
+private:
+    void cancelCurrentRequest();
+    void handleResponse(
+        const LanguageServerProtocol::DocumentRangeFormattingRequest::Response &response);
+
+    Client *m_client = nullptr; // not owned
+    QMetaObject::Connection m_cancelConnection;
+    TextEditor::TextDocument *m_document; // not owned
+    bool m_ignoreCancel = false;
+    QFutureInterface<Utils::Text::Replacements> m_progress;
+    Utils::optional<LanguageServerProtocol::MessageId> m_currentRequest;
+};
+
+} // namespace LanguageClient