/* -*- 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())

            m_pElement->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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