ClangCodeModel: Move completion code to its own set of files

Change-Id: Iad856881ace80896f4aceab3fbf129d7635de642
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangdcompletion.h

@@ -0,0 +1,62 @@
+
+#include <languageclient/languageclientcompletionassist.h>
+/****************************************************************************
+**
+** Copyright (C) 2022 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 <languageclient/languageclientcompletionassist.h>
+#include <languageserverprotocol/clientcapabilities.h>
+
+namespace TextEditor { class IAssistProcessor; }
+namespace ClangCodeModel::Internal {
+class ClangdClient;
+
+class ClangdCompletionAssistProvider : public LanguageClient::LanguageClientCompletionAssistProvider
+{
+public:
+    ClangdCompletionAssistProvider(ClangdClient *client);
+
+private:
+    TextEditor::IAssistProcessor *createProcessor(
+            const TextEditor::AssistInterface *interface) const override;
+
+    int activationCharSequenceLength() const override { return 3; }
+    bool isActivationCharSequence(const QString &sequence) const override;
+    bool isContinuationChar(const QChar &c) const override;
+
+    bool isInCommentOrString(const TextEditor::AssistInterface *interface) const;
+
+    ClangdClient * const m_client;
+};
+
+class ClangdCompletionCapabilities
+        : public LanguageServerProtocol::TextDocumentClientCapabilities::CompletionCapabilities
+{
+public:
+    explicit ClangdCompletionCapabilities(const JsonObject &object);
+};
+
+} // namespace ClangCodeModel::Internal