/* -*- 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 .
 */

#include "elementlist.hxx"

#include <string.h>
#include <string_view>

#include <cppuhelper/implbase.hxx>
#include <o3tl/safeint.hxx>
#include <utility>
#include <comphelper/diagnose_ex.hxx>
#include <unotools/weakref.hxx>

#include "element.hxx"
#include "document.hxx"

using namespace css::uno;
using namespace css::xml::dom;
using namespace css::xml::dom::events;
namespace DOM { class CElementListImpl; }

namespace DOM
{
    class WeakEventListener : public ::cppu::WeakImplHelper<css::xml::dom::events::XEventListener>
    {
    private:
        unotools::WeakReference<DOM::CElementListImpl> mxOwner;

    public:
        explicit WeakEventListener(const rtl::Reference<DOM::CElementListImpl>& rOwner)
            : mxOwner(rOwner)
        {
        }

        virtual void SAL_CALL handleEvent(const css::uno::Reference<css::xml::dom::events::XEvent>& rEvent) override
        {
            rtl::Reference<DOM::CElementListImpl> xOwner(mxOwner);
            if (xOwner)
                xOwner->handleEvent(rEvent);
        }
    };
}

namespace DOM
{

    static xmlChar* lcl_initXmlString(std::u16string_view rString)
    {
        OString const os =
            OUStringToOString(rString, RTL_TEXTENCODING_UTF8);
        xmlChar *const pRet = new xmlChar[os.getLength() + 1];
        strcpy(reinterpret_cast<char*>(pRet), os.getStr());
        return pRet;
    }

    CElementList::CElementList(::rtl::Reference<CElement> const& pElement,
            ::osl::Mutex & rMutex,
            std::u16string_view rName, OUString const*const pURI)
        : m_xImpl(new CElementListImpl(pElement, rMutex, rName, pURI))
    {
        if (pElement.is()) {
            m_xImpl->registerListener(*pElement);
        }
    }

    CElementListImpl::CElementListImpl(::rtl::Reference<CElement> pElement,
            ::osl::Mutex & rMutex,
            std::u16string_view rName, OUString const*const pURI)
        : m_pElement(std::move(pElement))
        , m_rMutex(rMutex)
        , m_pName(lcl_initXmlString(rName))
        , m_pURI(pURI ? lcl_initXmlString(*pURI) : nullptr)
        , m_bRebuild(true)
    {
    }

    CElementListImpl::~CElementListImpl()
    {
        if (m_xEventListener.is() && m_pElement.is())
        {
            Reference< XEventTarget > xTarget = m_pElement;
            assert(xTarget.is());
            if (!xTarget.is())
                return;
            xTarget->removeEventListener(u"DOMSubtreeModified"_ustr, m_xEventListener, false/*capture*/);
        }
    }

    void CElementListImpl::registerListener(CElement & rElement)
    {
        try {
            Reference< XEventTarget > const xTarget(
                    static_cast<XElement*>(& rElement), UNO_QUERY_THROW);
            m_xEventListener = new WeakEventListener(this);
            xTarget->addEventListener(u"DOMSubtreeModified"_ustr, m_xEventListener, false/*capture*/);
        } catch (const Exception &){
            TOOLS_WARN_EXCEPTION( "unoxml", "Exception caught while registering NodeList as listener");
        }
    }

    void CElementListImpl::buildlist(xmlNodePtr pNode, bool start)
    {
        // bail out if no rebuild is needed
        if (start) {
            if (!m_bRebuild)
            {
                return;
            } else {
                m_nodevector.clear();
                m_bRebuild = false; // don't rebuild until tree is mutated
            }
        }

        while (pNode != nullptr )
        {
            if (pNode->type == XML_ELEMENT_NODE &&
                (strcmp(reinterpret_cast<char const *>(pNode->name), reinterpret_cast<char*>(m_pName.get())) == 0))
            {
                if (!m_pURI) {
                    m_nodevector.push_back(pNode);
                } else {
                    if (pNode->ns != nullptr && (0 ==
                         strcmp(reinterpret_cast<char const *>(pNode->ns->href), reinterpret_cast<char*>(m_pURI.get()))))
                    {
                        m_nodevector.push_back(pNode);
                    }
                }
            }
            if (pNode->children != nullptr) buildlist(pNode->children, false);

            if (!start) pNode = pNode->next;
            else break; // fold back
        }
    }

    /**
    The number of nodes in the list.
    */
    sal_Int32 SAL_CALL CElementListImpl::getLength()
    {
        ::osl::MutexGuard const g(m_rMutex);

        if (!m_pElement.is()) { return 0; }

        // this has to be 'live'
        buildlist(m_pElement->GetNodePtr());
        return m_nodevector.size();
    }
    /**
    Returns the indexth item in the collection.
    */
    Reference< XNode > SAL_CALL CElementListImpl::item(sal_Int32 index)
    {
        if (index < 0) throw RuntimeException();

        ::osl::MutexGuard const g(m_rMutex);

        if (!m_pElement.is()) { return nullptr; }

        buildlist(m_pElement->GetNodePtr());
        if (m_nodevector.size() <= o3tl::make_unsigned(index)) {
            throw RuntimeException();
        }
        return m_pElement->GetOwnerDocument().GetCNode(m_nodevector[index]);
    }

    // tree mutations can change the list
    void SAL_CALL CElementListImpl::handleEvent(Reference< XEvent > const&)
    {
        ::osl::MutexGuard const g(m_rMutex);

        m_bRebuild = true;
    }
}

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