/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 */

/*

 * 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

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.xerces.internal.util;

import com.sun.org.apache.xerces.internal.xni.XNIException;

import com.sun.org.apache.xerces.internal.xni.XMLResourceIdentifier;

import com.sun.org.apache.xerces.internal.xni.grammars.XMLGrammarDescription;

import com.sun.org.apache.xerces.internal.xni.parser.XMLEntityResolver;

import com.sun.org.apache.xerces.internal.xni.parser.XMLInputSource;

import org.w3c.dom.ls.LSResourceResolver;

import org.w3c.dom.ls.LSInput;

import java.io.InputStream;

import java.io.IOException;

import java.io.Reader;

import java.io.StringReader;

/**

 * This class wraps DOM entity resolver to XNI entity resolver.

 *

 * @see LSResourceResolver

 *

 * @author Gopal Sharma, SUN MicroSystems Inc.

 * @author Elena Litani, IBM

 * @author Ramesh Mandava, Sun Microsystems

 * @LastModified: Nov 2017

 */

public class DOMEntityResolverWrapper

    implements XMLEntityResolver {

    //

    // Data

    //

    /** XML 1.0 type constant according to DOM L3 LS CR spec "http://www.w3.org/TR/2003/CR-DOM-Level-3-LS-20031107" */

    private static final String XML_TYPE = "http://www.w3.org/TR/REC-xml";

    /** XML Schema constant according to DOM L3 LS CR spec "http://www.w3.org/TR/2003/CR-DOM-Level-3-LS-20031107" */

    private static final String XSD_TYPE = "http://www.w3.org/2001/XMLSchema";

    /** The DOM entity resolver. */

    protected LSResourceResolver fEntityResolver;

    //

    // Constructors

    //

    /** Default constructor. */

    public DOMEntityResolverWrapper() {}

    /** Wraps the specified DOM entity resolver. */

    public DOMEntityResolverWrapper(LSResourceResolver entityResolver) {

        setEntityResolver(entityResolver);

    } // LSResourceResolver

    //

    // Public methods

    //

    /** Sets the DOM entity resolver. */

    public void setEntityResolver(LSResourceResolver entityResolver) {

        fEntityResolver = entityResolver;

    } // setEntityResolver(LSResourceResolver)

    /** Returns the DOM entity resolver. */

    public LSResourceResolver getEntityResolver() {

        return fEntityResolver;

    } // getEntityResolver():LSResourceResolver

    //

    // XMLEntityResolver methods

    //

    /**

     * Resolves an external parsed entity. If the entity cannot be

     * resolved, this method should return null.

     *

     * @param resourceIdentifier        description of the resource to be revsoved

     * @throws XNIException Thrown on general error.

     * @throws IOException  Thrown if resolved entity stream cannot be

     *                      opened or some other i/o error occurs.

     */

    public XMLInputSource resolveEntity(XMLResourceIdentifier resourceIdentifier)

        throws XNIException, IOException {

        // resolve entity using DOM entity resolver

        if (fEntityResolver != null) {

            // For entity resolution the type of the resource would be  XML TYPE

            // DOM L3 LS spec mention only the XML 1.0 recommendation right now

            LSInput inputSource =

                resourceIdentifier == null

                    ? fEntityResolver.resolveResource(

                        null,

                        null,

                        null,

                        null,

                        null)

                    : fEntityResolver.resolveResource(

                        getType(resourceIdentifier),

                        resourceIdentifier.getNamespace(),

                        resourceIdentifier.getPublicId(),

                        resourceIdentifier.getLiteralSystemId(),

                        resourceIdentifier.getBaseSystemId());

            if (inputSource != null) {

                String publicId = inputSource.getPublicId();

                String systemId = inputSource.getSystemId();

                String baseSystemId = inputSource.getBaseURI();

                InputStream byteStream = inputSource.getByteStream();

                Reader charStream = inputSource.getCharacterStream();

                String encoding = inputSource.getEncoding();

                String data = inputSource.getStringData();

                /**

                 * An LSParser looks at inputs specified in LSInput in

                 * the following order: characterStream, byteStream,

                 * stringData, systemId, publicId.

                 */

                XMLInputSource xmlInputSource =

                    new XMLInputSource(publicId, systemId, baseSystemId, true);

                if (charStream != null) {

                    xmlInputSource.setCharacterStream(charStream);

                }

                else if (byteStream != null) {

                    xmlInputSource.setByteStream(byteStream);

                }

                else if (data != null && data.length() != 0) {

                    xmlInputSource.setCharacterStream(new StringReader(data));

                }

                xmlInputSource.setEncoding(encoding);

                return xmlInputSource;

            }

        }

        // unable to resolve entity

        return null;

    } // resolveEntity(String,String,String):XMLInputSource

    /** Determines the type of resource being resolved **/

    private String getType(XMLResourceIdentifier resourceIdentifier) {

        if (resourceIdentifier instanceof XMLGrammarDescription) {

            XMLGrammarDescription desc = (XMLGrammarDescription) resourceIdentifier;

            if (XMLGrammarDescription.XML_SCHEMA.equals(desc.getGrammarType())) {

                return XSD_TYPE;

            }

        }

        return XML_TYPE;

    } // getType(XMLResourceIdentifier):String

} // DOMEntityResolverWrapper