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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_VCL_PTR_HXX
+#define INCLUDED_VCL_PTR_HXX
+
+#include <sal/config.h>
+
+#include <rtl/ref.hxx>
+
+#include <utility>
+#include <type_traits>
+
+#ifdef DBG_UTIL
+#ifndef _WIN32
+#include <vcl/vclmain.hxx>
+#endif
+#endif
+
+class VclReferenceBase;
+
+namespace vcl::detail {
+
+template<typename>
+constexpr bool isIncompleteOrDerivedFromVclReferenceBase(...) { return true; }
+
+template<typename T> constexpr bool isIncompleteOrDerivedFromVclReferenceBase(
+    int (*)[sizeof(T)])
+{ return std::is_base_of<VclReferenceBase, T>::value; }
+
+} // namespace vcl::detail
+
+/**
+ * A thin wrapper around rtl::Reference to implement the acquire and dispose semantics we want for references to vcl::Window subclasses.
+ *
+ * For more details on the design please see vcl/README.lifecycle
+ *
+ * @param reference_type must be a subclass of vcl::Window
+ */
+template <class reference_type>
+class VclPtr
+{
+    static_assert(
+        vcl::detail::isIncompleteOrDerivedFromVclReferenceBase<reference_type>(
+            nullptr),
+        "template argument type must be derived from VclReferenceBase");
+
+    ::rtl::Reference<reference_type> m_rInnerRef;
+
+public:
+    /** Constructor...
+     */
+    VclPtr()
+        : m_rInnerRef()
+    {}
+
+    /** Constructor...
+     */
+    VclPtr (reference_type * pBody)
+        : m_rInnerRef(pBody)
+    {}
+
+    /** Constructor... that doesn't take a ref.
+     */
+    VclPtr (reference_type * pBody, __sal_NoAcquire)
+        : m_rInnerRef(pBody, SAL_NO_ACQUIRE)
+    {}
+
+    /** Up-casting conversion constructor: Copies interface reference.
+
+        Does not work for up-casts to ambiguous bases.  For the special case of
+        up-casting to Reference< XInterface >, see the corresponding conversion
+        operator.
+
+        @param rRef another reference
+    */
+    template< class derived_type >
+    VclPtr(
+        const VclPtr< derived_type > & rRef,
+        typename std::enable_if<
+            std::is_base_of<reference_type, derived_type>::value, int>::type
+            = 0 )
+        : m_rInnerRef( static_cast<reference_type*>(rRef) )
+    {
+    }
+
+#if defined(DBG_UTIL) && !defined(_WIN32)
+    ~VclPtr()
+    {
+        assert(m_rInnerRef.get() == nullptr || vclmain::isAlive());
+        // We can be one of the intermediate counts, but if we are the last
+        // VclPtr keeping this object alive, then something forgot to call dispose().
+        assert((!m_rInnerRef.get() || m_rInnerRef->isDisposed() || m_rInnerRef->getRefCount() > 1)
+                && "someone forgot to call dispose()");
+    }
+    VclPtr(VclPtr const &) = default;
+    VclPtr(VclPtr &&) = default;
+    VclPtr & operator =(VclPtr const &) = default;
+    VclPtr & operator =(VclPtr &&) = default;
+#endif
+
+    /**
+     * A construction helper for VclPtr. Since VclPtr types are created
+     * with a reference-count of one - to help fit into the existing
+     * code-flow; this helps us to construct them easily.
+     *
+     * For more details on the design please see vcl/README.lifecycle
+     *
+     * @tparam reference_type must be a subclass of vcl::Window
+     */
+    template<typename... Arg> [[nodiscard]] static VclPtr< reference_type > Create(Arg &&... arg)
+    {
+        return VclPtr< reference_type >( new reference_type(std::forward<Arg>(arg)...), SAL_NO_ACQUIRE );
+    }
+
+    /** Probably most common used: handle->someBodyOp().
+     */
+    reference_type * operator->() const
+    {
+        return m_rInnerRef.get();
+    }
+
+    /** Get the body. Can be used instead of operator->().
+         I.e. handle->someBodyOp() and handle.get()->someBodyOp()
+         are the same.
+      */
+    reference_type * get() const
+    {
+        return m_rInnerRef.get();
+    }
+
+    void set(reference_type *pBody)
+    {
+        m_rInnerRef.set(pBody);
+    }
+
+    void reset(reference_type *pBody)
+    {
+        m_rInnerRef.set(pBody);
+    }
+
+    /** Up-casting copy assignment operator.
+
+        Does not work for up-casts to ambiguous bases.
+
+        @param rRef another reference
+    */
+    template<typename derived_type>
+    typename std::enable_if<
+        std::is_base_of<reference_type, derived_type>::value,
+        VclPtr &>::type
+    operator =(VclPtr<derived_type> const & rRef)
+    {
+        m_rInnerRef.set(rRef.get());
+        return *this;
+    }
+
+    VclPtr & operator =(reference_type * pBody)
+    {
+        m_rInnerRef.set(pBody);
+        return *this;
+    }
+
+    operator reference_type * () const
+    {
+        return m_rInnerRef.get();
+    }
+
+    explicit operator bool () const
+    {
+        return m_rInnerRef.get() != nullptr;
+    }
+
+    void clear()
+    {
+        m_rInnerRef.clear();
+    }
+
+    void reset()
+    {
+        m_rInnerRef.clear();
+    }
+
+    void disposeAndClear()
+    {
+        // hold it alive for the lifetime of this method
+        ::rtl::Reference<reference_type> aTmp(std::move(m_rInnerRef));
+        // coverity[use_after_move : SUPPRESS] - the move ctor above must take care of it
+        assert(!m_rInnerRef);
+        if (aTmp.get()) {
+            aTmp->disposeOnce();
+        }
+    }
+
+    /** Needed to place VclPtr's into STL collection.
+     */
+    bool operator< (const VclPtr<reference_type> & handle) const
+    {
+        return (m_rInnerRef < handle.m_rInnerRef);
+    }
+}; // class VclPtr
+
+template<typename T1, typename T2>
+inline bool operator ==(VclPtr<T1> const & p1, VclPtr<T2> const & p2) {
+    return p1.get() == p2.get();
+}
+
+template<typename T> inline bool operator ==(VclPtr<T> const & p1, T const * p2)
+{
+    return p1.get() == p2;
+}
+
+template<typename T> inline bool operator ==(VclPtr<T> const & p1, T * p2) {
+    return p1.get() == p2;
+}
+
+template<typename T> inline bool operator ==(T const * p1, VclPtr<T> const & p2)
+{
+    return p1 == p2.get();
+}
+
+template<typename T> inline bool operator ==(T * p1, VclPtr<T> const & p2) {
+    return p1 == p2.get();
+}
+
+template<typename T1, typename T2>
+inline bool operator !=(VclPtr<T1> const & p1, VclPtr<T2> const & p2) {
+    return !(p1 == p2);
+}
+
+template<typename T> inline bool operator !=(VclPtr<T> const & p1, T const * p2)
+{
+    return !(p1 == p2);
+}
+
+template<typename T> inline bool operator !=(VclPtr<T> const & p1, T * p2) {
+    return !(p1 == p2);
+}
+
+template<typename T> inline bool operator !=(T const * p1, VclPtr<T> const & p2)
+{
+    return !(p1 == p2);
+}
+
+template<typename T> inline bool operator !=(T * p1, VclPtr<T> const & p2) {
+    return !(p1 == p2);
+}
+
+/**
+ * A construction helper for a temporary VclPtr. Since VclPtr types
+ * are created with a reference-count of one - to help fit into
+ * the existing code-flow; this helps us to construct them easily.
+ * see also VclPtr::Create and ScopedVclPtr
+ *
+ * For more details on the design please see vcl/README.lifecycle
+ *
+ * @param reference_type must be a subclass of vcl::Window
+ */
+template <class reference_type>
+class SAL_WARN_UNUSED VclPtrInstance final : public VclPtr<reference_type>
+{
+public:
+    template<typename... Arg> VclPtrInstance(Arg &&... arg)
+        : VclPtr<reference_type>( new reference_type(std::forward<Arg>(arg)...), SAL_NO_ACQUIRE )
+    {
+    }
+
+    /**
+     * Override and disallow this, to prevent people accidentally calling it and actually
+     * getting VclPtr::Create and getting a naked VclPtr<> instance
+     */
+    template<typename... Arg> static VclPtrInstance< reference_type > Create(Arg &&... ) = delete;
+};
+
+template <class reference_type>
+class ScopedVclPtr : public VclPtr<reference_type>
+{
+public:
+    /** Constructor...
+     */
+    ScopedVclPtr()
+        : VclPtr<reference_type>()
+    {}
+
+    /** Constructor
+     */
+    ScopedVclPtr (reference_type * pBody)
+        : VclPtr<reference_type>(pBody)
+    {}
+
+    /** Copy constructor...
+     */
+    ScopedVclPtr (const VclPtr<reference_type> & handle)
+        : VclPtr<reference_type>(handle)
+    {}
+
+    /**
+       Assignment that releases the last reference.
+     */
+    void disposeAndReset(reference_type *pBody)
+    {
+        if (pBody != this->get()) {
+            VclPtr<reference_type>::disposeAndClear();
+            VclPtr<reference_type>::set(pBody);
+        }
+    }
+
+    /**
+       Assignment that releases the last reference.
+     */
+    ScopedVclPtr<reference_type>& operator = (reference_type * pBody)
+    {
+        disposeAndReset(pBody);
+        return *this;
+    }
+
+    /** Up-casting conversion constructor: Copies interface reference.
+
+        Does not work for up-casts to ambiguous bases.  For the special case of
+        up-casting to Reference< XInterface >, see the corresponding conversion
+        operator.
+
+        @param rRef another reference
+    */
+    template< class derived_type >
+    ScopedVclPtr(
+        const VclPtr< derived_type > & rRef,
+        typename std::enable_if<
+            std::is_base_of<reference_type, derived_type>::value, int>::type
+            = 0 )
+        : VclPtr<reference_type>( rRef )
+    {
+    }
+
+    /** Up-casting assignment operator.
+
+        Does not work for up-casts to ambiguous bases.
+
+        @param rRef another VclPtr
+    */
+    template<typename derived_type>
+    typename std::enable_if<
+        std::is_base_of<reference_type, derived_type>::value,
+        ScopedVclPtr &>::type
+    operator =(VclPtr<derived_type> const & rRef)
+    {
+        disposeAndReset(rRef.get());
+        return *this;
+    }
+
+    /**
+     * Override and disallow this, to prevent people accidentally calling it and actually
+     * getting VclPtr::Create and getting a naked VclPtr<> instance
+     */
+    template<typename... Arg> static ScopedVclPtr< reference_type > Create(Arg &&... ) = delete;
+
+    ~ScopedVclPtr()
+    {
+        VclPtr<reference_type>::disposeAndClear();
+        assert(VclPtr<reference_type>::get() == nullptr); // make sure there are no lingering references
+    }
+
+private:
+    // Most likely we don't want this default copy-constructor.
+    ScopedVclPtr (const ScopedVclPtr<reference_type> &) = delete;
+    // And certainly we don't want a default assignment operator.
+    ScopedVclPtr<reference_type>& operator = (const ScopedVclPtr<reference_type> &) = delete;
+    // And disallow reset as that doesn't call disposeAndClear on the original reference
+    void reset() = delete;
+    void reset(reference_type *pBody) = delete;
+
+protected:
+    ScopedVclPtr (reference_type * pBody, __sal_NoAcquire)
+        : VclPtr<reference_type>(pBody, SAL_NO_ACQUIRE)
+    {}
+};
+
+/**
+ * A construction helper for ScopedVclPtr. Since VclPtr types are created
+ * with a reference-count of one - to help fit into the existing
+ * code-flow; this helps us to construct them easily.
+ *
+ * For more details on the design please see vcl/README.lifecycle
+ *
+ * @param reference_type must be a subclass of vcl::Window
+ */
+#if defined _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4521) // " multiple copy constructors specified"
+#endif
+template <class reference_type>
+class SAL_WARN_UNUSED ScopedVclPtrInstance final : public ScopedVclPtr<reference_type>
+{
+public:
+    template<typename... Arg> ScopedVclPtrInstance(Arg &&... arg)
+        : ScopedVclPtr<reference_type>( new reference_type(std::forward<Arg>(arg)...), SAL_NO_ACQUIRE )
+    {
+    }
+
+    /**
+     * Override and disallow this, to prevent people accidentally calling it and actually
+     * getting VclPtr::Create and getting a naked VclPtr<> instance
+     */
+    template<typename... Arg> static ScopedVclPtrInstance< reference_type > Create(Arg &&...) = delete;
+
+private:
+    // Prevent the above perfect forwarding ctor from hijacking (accidental)
+    // attempts at ScopedVclPtrInstance copy construction (where the hijacking
+    // would typically lead to somewhat obscure error messages); both non-const
+    // and const variants are needed here, as the ScopedVclPtr base class has a
+    // const--variant copy ctor, so the implicitly declared copy ctor for
+    // ScopedVclPtrInstance would also be the const variant, so non-const copy
+    // construction attempts would be hijacked by the perfect forwarding ctor;
+    // but if we only declared a non-const variant here, the const variant would
+    // no longer be implicitly declared (as there would already be an explicitly
+    // declared copy ctor), so const copy construction attempts would then be
+    // hijacked by the perfect forwarding ctor:
+    ScopedVclPtrInstance(ScopedVclPtrInstance &) = delete;
+    ScopedVclPtrInstance(ScopedVclPtrInstance const &) = delete;
+};
+#if defined _MSC_VER
+#pragma warning(pop)
+#endif
+
+#endif // INCLUDED_VCL_PTR_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */