/*
    SPDX-FileCopyrightText: 2006 Hamish Rodda <rodda@kde.org>
    SPDX-FileCopyrightText: 2007-2008 David Nolden <david.nolden.kdevelop@art-master.de>

    SPDX-License-Identifier: LGPL-2.0-only
*/

#ifndef KDEVPLATFORM_DUCHAINBASE_H
#define KDEVPLATFORM_DUCHAINBASE_H

#include <language/languageexport.h>
#include "appendedlist.h"
#include "duchainpointer.h"
#include <language/editor/persistentmovingrange.h>
#include <language/editor/rangeinrevision.h>

namespace KTextEditor {
class Cursor;
class Range;
}

namespace KDevelop {
class DUContext;
class TopDUContext;
class DUChainBase;
class IndexedString;

///Use this to declare the data functions in your DUChainBase based class. @warning Behind this macro, the access will be "public".
#define DUCHAIN_DECLARE_DATA(Class) \
    inline class Class ## Data * d_func_dynamic() { makeDynamic(); return reinterpret_cast<Class ## Data*>(d_ptr); } \
    inline const class Class ## Data* d_func() const { return reinterpret_cast<const Class ## Data*>(d_ptr); } \
public: using Data = Class ## Data; \
private:

#define DUCHAIN_D(Class) const Class ## Data * const d = d_func()
#define DUCHAIN_D_DYNAMIC(Class) Class ## Data * const d = d_func_dynamic()

///@note When a data-item is stored on disk, no destructors of contained items will be called while destruction.
///DUChainBase assumes that each item that has constant data, is stored on disk.
///However the destructor is called even on constant items, when they have been replaced with a dynamic item.
///This tries to keep constructor/destructor count consistency persistently, which allows doing static reference-counting
///using contained classes in their constructor/destructors(For example the class Utils::StorableSet).
///This means that the data of all items that are stored to disk _MUST_ be made constant before their destruction.
///This also means that every item that is "semantically" deleted, _MUST_ have dynamic data before its destruction.
///This also means that DUChainBaseData based items should never be cloned using memcpy, but rather always using the copy-constructor,
///even if both sides are constant.
class KDEVPLATFORMLANGUAGE_EXPORT DUChainBaseData
{
public:
    DUChainBaseData()
    {
        initializeAppendedLists();
    }

    DUChainBaseData(const DUChainBaseData& rhs) : m_range(rhs.m_range)
        , classId(rhs.classId)
    {
        initializeAppendedLists();
    }

    ~DUChainBaseData()
    {
        freeAppendedLists();
    }

    DUChainBaseData& operator=(const DUChainBaseData& rhs) = delete;

    RangeInRevision m_range;

    APPENDED_LISTS_STUB(DUChainBaseData)

    quint16 classId = 0;

    bool isDynamic() const
    {
        return m_dynamic;
    }

    /**
     * Internal setup for the data structure.
     *
     * This must be called from actual class that belongs to this data(not parent classes), and the class must have the
     * "Identity" enumerator with a unique identity. Do NOT call this in copy-constructors!
     */
    template <class T>
    void setClassId(T*)
    {
        static_assert(T::Identity < std::numeric_limits<decltype(classId)>::max(), "Class ID out of bounds");
        classId = T::Identity;
    }

    uint classSize() const;

    ///This is called whenever the data-object is being deleted memory-wise, but not semantically(Which means it stays on disk)
    ///Implementations of parent-classes must always be called
    void freeDynamicData()
    {
    }

    ///Used to decide whether a constructed item should create constant data.
    ///The default is "false", so dynamic data is created by default.
    ///This is stored thread-locally.
    static bool& shouldCreateConstantData();

    ///Returns whether initialized objects should be created as dynamic objects
    static bool appendedListDynamicDefault()
    {
        return !shouldCreateConstantData();
    }
};

/**
 * Base class for definition-use chain objects.
 *
 * This class provides a thread safe pointer type to reference duchain objects
 * while the DUChain mutex is not held (\see DUChainPointer)
 */

class KDEVPLATFORMLANGUAGE_EXPORT DUChainBase
{
public:
    /**
     * Constructor.
     *
     * \param range range of the alias declaration's identifier
     */
    explicit DUChainBase(const RangeInRevision& range);
    /// Destructor
    virtual ~DUChainBase();

    /**
     * Determine the top context to which this object belongs.
     */
    virtual TopDUContext* topContext() const;

    /**
     * Returns a special pointer that can be used to track the existence of a du-chain object across locking-cycles.
     * @see DUChainPointerData
     * */
    const QExplicitlySharedDataPointer<DUChainPointerData>& weakPointer() const;

    virtual IndexedString url() const;

    enum {
        Identity = 1
    };

    ///After this was called, the data-pointer is dynamic. It is cloned if needed.
    void makeDynamic();

    explicit DUChainBase(DUChainBaseData& dd);

    DUChainBase& operator=(const DUChainBase& rhs) = delete;

    ///This must only be used to change the storage-location or storage-kind(dynamic/constant) of the data, but
    ///the data must always be equal!
    virtual void setData(DUChainBaseData*, bool constructorCalled = true);

    ///Returns the range assigned to this object, in the document revision when this document was last parsed.
    RangeInRevision range() const;

    ///Changes the range assigned to this object, in the document revision when this document is parsed.
    void setRange(const RangeInRevision& range);

    ///Returns the range assigned to this object, transformed into the current revision of the document.
    ///@warning This must only be called from the foreground thread, or with the foreground lock acquired.
    KTextEditor::Range rangeInCurrentRevision() const;

    ///Returns the range assigned to this object, transformed into the current revision of the document.
    ///The returned object is unique at each call, so you can use it and change it in whatever way you want.
    ///@warning This must only be called from the foreground thread, or with the foreground lock acquired.
    PersistentMovingRange::Ptr createRangeMoving() const;

    ///Transforms the given cursor in the current document revision to its according position
    ///in the parsed document containing this duchain object. The resulting cursor will be directly comparable to the non-translated
    ///range() members in the duchain, but only for one duchain locking cycle.
    ///@warning This must only be called from the foreground thread, or with the foreground lock acquired.
    CursorInRevision transformToLocalRevision(const KTextEditor::Cursor& cursor) const;

    ///Transforms the given range in the current document revision to its according position
    ///in the parsed document containing this duchain object. The resulting cursor will be directly comparable to the non-translated
    ///range() members in the duchain, but only for one duchain locking cycle.
    ///@warning This must only be called from the foreground thread, or with the foreground lock acquired.
    RangeInRevision transformToLocalRevision(const KTextEditor::Range& range) const;

    KTextEditor::Cursor transformFromLocalRevision(const CursorInRevision& cursor) const;

    KTextEditor::Range transformFromLocalRevision(const RangeInRevision& range) const;

protected:
    /**
     * Creates a duchain object that uses the data of the given one, and will not delete it on destruction.
     * The data will be shared, and this object must be deleted before the given one is.
     */
    DUChainBase(DUChainBase& rhs);

    /**
     * Constructor for copy constructors in subclasses.
     *
     * \param dd data to use.
     * \param range text range which this object covers.
     */
    DUChainBase(DUChainBaseData& dd, const RangeInRevision& range);

    ///Called after loading to rebuild the dynamic data. If this is a context, this should recursively work on all sub-contexts.
    virtual void rebuildDynamicData(DUContext* parent, uint ownIndex);

    /// Data pointer that is shared across all the inheritance hierarchy
    DUChainBaseData* d_ptr;

private:

    mutable QExplicitlySharedDataPointer<DUChainPointerData> m_ptr;

public:
    DUCHAIN_DECLARE_DATA(DUChainBase)
};
}

#endif // KDEVPLATFORM_DUCHAINBASE_H