Introduce codemodelbackend process and library

This is a partial result of wip/clang-oop. More will follow.

This allows us to invoke the completion out of the Qt Creator process
and thus safes us as against libclang crashes.

At this point only the completion use case is supported.

Some notes on the individual components:

 src/libs/codemodelbackendipc
  * library encapsulating the inter process communication handling
  * used by the backend application and in a follow-up change by the
    creator integration

 src/libs/3rdparty/sqlite
  * version 3.8.10.2
  * dependency of codemodelbackendipc, will be used to storage indexing
    data, among others

 src/tools/codemodelbackend
  * the backend application

 tests/unit:
  * unit tests

Change-Id: I91a48e27467581a22fb760a18d8eb926008fea60
Reviewed-by: Alessandro Portale <alessandro.portale@theqtcompany.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>
Reviewed-by: Marco Bubke <marco.bubke@theqtcompany.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

src/libs/sqlite/utf8string.h

@@ -0,0 +1,142 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 Digia.  For licensing terms and
+** conditions see http://www.qt.io/licensing.  For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef UTF8STRING_H
+#define UTF8STRING_H
+
+#include <QByteArray>
+#include <QMetaType>
+
+#include "sqliteglobal.h"
+
+class Utf8StringVector;
+class Utf8String;
+
+class SQLITE_EXPORT Utf8String
+{
+    friend class Utf8StringVector;
+
+    friend SQLITE_EXPORT const Utf8String operator +(const Utf8String &first, const Utf8String &second);
+
+    friend SQLITE_EXPORT bool operator !=(const Utf8String &first, const Utf8String &second);
+    friend SQLITE_EXPORT bool operator ==(const Utf8String &first, const Utf8String &second);
+    friend SQLITE_EXPORT bool operator ==(const Utf8String &first, const char *second);
+    friend SQLITE_EXPORT bool operator <(const Utf8String &first, const Utf8String &second);
+
+    friend SQLITE_EXPORT QDataStream &operator<<(QDataStream &datastream, const Utf8String &text);
+    friend SQLITE_EXPORT QDataStream &operator>>(QDataStream &datastream, Utf8String &text);
+
+public:
+    Utf8String() = default;
+    explicit Utf8String(const char *utf8Text, int size);
+    Utf8String(const QString &text);
+
+    const char *constData() const;
+
+    int byteSize() const;
+
+    static Utf8String fromUtf8(const char *utf8Text);
+    static Utf8String fromByteArray(const QByteArray &utf8ByteArray);
+    const QByteArray &toByteArray() const;
+
+    static Utf8String fromString(const QString &text);
+    QString toString() const;
+
+    Utf8String mid(int position, int length = -1) const;
+    void replace(const Utf8String &before, const Utf8String &after);
+    Utf8StringVector split(char separator) const;
+
+    void clear();
+
+    void append(const Utf8String &textToAppend);
+    bool contains(const Utf8String &text) const;
+    bool contains(const char *text) const;
+    bool contains(char character) const;
+    bool startsWith(const Utf8String &text) const;
+    bool startsWith(const char *text) const;
+    bool startsWith(char character) const;
+    bool isEmpty() const;
+    bool hasContent() const;
+
+    void reserve(int reserveSize);
+
+    static Utf8String number(int number, int base=10);
+
+    const Utf8String &operator+=(const Utf8String &text);
+
+    static void registerType();
+
+    operator QString () const;
+    operator const QByteArray & () const;
+
+protected:
+    explicit Utf8String(const QByteArray &utf8ByteArray);
+
+private:
+    QByteArray byteArray;
+};
+
+SQLITE_EXPORT const Utf8String operator +(const Utf8String &first, const Utf8String &second);
+
+SQLITE_EXPORT bool operator !=(const Utf8String &first, const Utf8String &second);
+SQLITE_EXPORT bool operator ==(const Utf8String &first, const Utf8String &second);
+SQLITE_EXPORT bool operator ==(const Utf8String &first, const char *second);
+SQLITE_EXPORT bool operator <(const Utf8String &first, const Utf8String &second);
+
+SQLITE_EXPORT QDataStream &operator<<(QDataStream &datastream, const Utf8String &text);
+SQLITE_EXPORT QDataStream &operator>>(QDataStream &datastream, Utf8String &text);
+SQLITE_EXPORT QDebug operator<<(QDebug debug, const Utf8String &text);
+SQLITE_EXPORT void PrintTo(const Utf8String &text, ::std::ostream* os);
+
+#if defined(Q_COMPILER_LAMBDA)
+
+#  define Utf8StringLiteral(str) \
+    ([]() -> Utf8String { \
+        enum { Size = sizeof(str) - 1 }; \
+        static const QStaticByteArrayData<Size> qbytearray_literal = { \
+            Q_STATIC_BYTE_ARRAY_DATA_HEADER_INITIALIZER(Size), \
+            str }; \
+        QByteArrayDataPtr holder = { qbytearray_literal.data_ptr() }; \
+        const QByteArray byteArray(holder); \
+        return Utf8String::fromByteArray(byteArray); \
+    }()) \
+    /**/
+
+#endif
+
+#ifndef Utf8StringLiteral
+// no lambdas, not GCC, just return a temporary QByteArray
+
+# define Utf8StringLiteral(str) Utf8String(str, sizeof(str) - 1)
+#endif
+
+Q_DECLARE_METATYPE(Utf8String)
+
+#endif // UTF8STRING_H