Sqlite: Add session support

Session are captured by hooking in the sqlite changes. They are saved in
blobs and containing inserts, update and deletes. Because the are
semantically coupled to translactions we add a

Change-Id: Ie095558ebc50601fcaae32958ebeeb98b72d73b9
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/sqlite/sqlitesessionchangeset.h

@@ -0,0 +1,80 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
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+** and conditions see https://www.qt.io/terms-conditions. For further
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+**
+** 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
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+****************************************************************************/
+
+#pragma once
+
+#include "sqliteglobal.h"
+
+#include <utils/span.h>
+
+#include <memory>
+#include <vector>
+
+#include <iosfwd>
+
+namespace Sqlite {
+
+class Sessions;
+
+class SessionChangeSet
+{
+public:
+    SessionChangeSet(Utils::span<const byte> blob);
+    SessionChangeSet(Sessions &session);
+    ~SessionChangeSet();
+    SessionChangeSet(const SessionChangeSet &) = delete;
+    void operator=(const SessionChangeSet &) = delete;
+    SessionChangeSet(SessionChangeSet &&other) noexcept
+    {
+        SessionChangeSet temp;
+        swap(temp, other);
+        swap(temp, *this);
+    }
+    void operator=(SessionChangeSet &);
+
+    Utils::span<const byte> asSpan() const;
+
+    friend void swap(SessionChangeSet &first, SessionChangeSet &second) noexcept
+    {
+        SessionChangeSet temp;
+        std::swap(temp.data, first.data);
+        std::swap(temp.size, first.size);
+        std::swap(first.data, second.data);
+        std::swap(first.size, second.size);
+        std::swap(temp.data, second.data);
+        std::swap(temp.size, second.size);
+    }
+
+private:
+    SessionChangeSet() = default;
+
+public:
+    void *data = nullptr;
+    int size = {};
+};
+
+using SessionChangeSets = std::vector<SessionChangeSet>;
+
+} // namespace Sqlite