1 files changed, 142 insertions, 0 deletions
diff --git a/src/corelib/tools/qshareddata_impl.h b/src/corelib/tools/qshareddata_impl.h
new file mode 100644
index 0000000000..e0b4695e36
--- /dev/null
+++ b/src/corelib/tools/qshareddata_impl.h
@@ -0,0 +1,142 @@
+// Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#if 0
+#pragma qt_sync_skip_header_check
+#pragma qt_sync_stop_processing
+#endif
+
+#ifndef QSHAREDDATA_IMPL_H
+#define QSHAREDDATA_IMPL_H
+
+#include <QtCore/qglobal.h>
+#include <QtCore/qshareddata.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtPrivate {
+
+template <typename T>
+class QExplicitlySharedDataPointerV2
+{
+    T *d;
+
+public:
+    constexpr QExplicitlySharedDataPointerV2() noexcept : d(nullptr) {}
+
+    explicit QExplicitlySharedDataPointerV2(T *t) noexcept
+        : d(t)
+    {
+        if (d)
+            d->ref.ref();
+    }
+
+    QExplicitlySharedDataPointerV2(T *t, QAdoptSharedDataTag) noexcept
+        : d(t)
+    {
+    }
+
+    QExplicitlySharedDataPointerV2(const QExplicitlySharedDataPointerV2 &other) noexcept
+        : d(other.d)
+    {
+        if (d)
+            d->ref.ref();
+    }
+
+    QExplicitlySharedDataPointerV2 &operator=(const QExplicitlySharedDataPointerV2 &other) noexcept
+    {
+        QExplicitlySharedDataPointerV2 copy(other);
+        swap(copy);
+        return *this;
+    }
+
+    QExplicitlySharedDataPointerV2(QExplicitlySharedDataPointerV2 &&other) noexcept
+        : d(std::exchange(other.d, nullptr))
+    {
+    }
+
+    QExplicitlySharedDataPointerV2 &operator=(QExplicitlySharedDataPointerV2 &&other) noexcept
+    {
+        QExplicitlySharedDataPointerV2 moved(std::move(other));
+        swap(moved);
+        return *this;
+    }
+
+    ~QExplicitlySharedDataPointerV2()
+    {
+        if (d && !d->ref.deref())
+            delete d;
+    }
+
+    void detach()
+    {
+        if (!d) {
+            // should this codepath be here on in all user's detach()?
+            d = new T;
+            d->ref.ref();
+        } else if (d->ref.loadRelaxed() != 1) {
+            // TODO: qAtomicDetach here...?
+            QExplicitlySharedDataPointerV2 copy(new T(*d));
+            swap(copy);
+        }
+    }
+
+    void reset(T *t = nullptr) noexcept
+    {
+        if (d && !d->ref.deref())
+            delete d;
+        d = t;
+        if (d)
+            d->ref.ref();
+    }
+
+    constexpr T *take() noexcept
+    {
+        return std::exchange(d, nullptr);
+    }
+
+    bool isShared() const noexcept
+    {
+        return d && d->ref.loadRelaxed() != 1;
+    }
+
+    constexpr void swap(QExplicitlySharedDataPointerV2 &other) noexcept
+    {
+        qt_ptr_swap(d, other.d);
+    }
+
+    // important change from QExplicitlySharedDataPointer: deep const
+    constexpr T &operator*() { return *d; }
+    constexpr T *operator->() { return d; }
+    constexpr const T &operator*() const { return *d; }
+    constexpr const T *operator->() const { return d; }
+
+    constexpr T *data() noexcept { return d; }
+    constexpr const T *data() const noexcept { return d; }
+
+    constexpr explicit operator bool() const noexcept { return d; }
+
+    constexpr friend bool operator==(const QExplicitlySharedDataPointerV2 &lhs,
+                                     const QExplicitlySharedDataPointerV2 &rhs) noexcept
+    {
+        return lhs.d == rhs.d;
+    }
+
+    constexpr friend bool operator!=(const QExplicitlySharedDataPointerV2 &lhs,
+                                     const QExplicitlySharedDataPointerV2 &rhs) noexcept
+    {
+        return lhs.d != rhs.d;
+    }
+};
+
+template <typename T>
+constexpr void swap(QExplicitlySharedDataPointerV2<T> &lhs, QExplicitlySharedDataPointerV2<T> &rhs) noexcept
+{
+    lhs.swap(rhs);
+}
+
+} // namespace QtPrivate
+
+QT_END_NAMESPACE
+
+#endif // QSHAREDDATA_IMPL_H