Clang: Add clang query

Clang query is mechanism to use AST matcher to search for code. Think
about regular expression but in the context of AST. So you get a semantic
search tool for C++.

Change-Id: I72e882c5b53a0c52f352a3664847c4c3e4f6fc2e
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/tools/clangrefactoringbackend/source/clangtool.h

@@ -0,0 +1,86 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 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 "refactoringcompilationdatabase.h"
+
+#include <clangrefactoringbackend_global.h>
+
+#include <sourcelocationscontainer.h>
+
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#endif
+
+#include "clang/Tooling/Refactoring.h"
+
+#if defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
+
+#include <string>
+#include <vector>
+
+namespace ClangBackEnd {
+
+struct FileContent
+{
+    FileContent(const std::string &directory,
+                const std::string &fileName,
+                const std::string &content,
+                const std::vector<std::string> &commandLine)
+        : directory(directory),
+          fileName(fileName),
+          filePath(directory + nativeSeperator + fileName),
+          content(content),
+          commandLine(commandLine)
+    {}
+
+    std::string directory;
+    std::string fileName;
+    std::string filePath;
+    std::string content;
+    std::vector<std::string> commandLine;
+};
+
+class ClangTool
+{
+public:
+    void addFile(std::string &&directory,
+                 std::string &&fileName,
+                 std::string &&content,
+                 std::vector<std::string> &&commandLine);
+
+    clang::tooling::ClangTool createTool() const;
+
+private:
+    RefactoringCompilationDatabase compilationDatabase;
+    std::vector<FileContent> fileContents;
+    std::vector<std::string> sourceFilePaths;
+};
+
+} // namespace ClangBackEnd